diff options
Diffstat (limited to 'gdb/doc/gdbint.texinfo')
| -rw-r--r-- | gdb/doc/gdbint.texinfo | 1593 |
1 files changed, 976 insertions, 617 deletions
diff --git a/gdb/doc/gdbint.texinfo b/gdb/doc/gdbint.texinfo index 952199e..4780abe 100644 --- a/gdb/doc/gdbint.texinfo +++ b/gdb/doc/gdbint.texinfo @@ -35,6 +35,9 @@ regarded as a program in the language TeX). @setchapternewpage off @settitle @value{GDBN} Internals +@syncodeindex fn cp +@syncodeindex vr cp + @titlepage @title @value{GDBN} Internals @subtitle{A guide to the internals of the GNU debugger} @@ -93,49 +96,54 @@ as the mechanisms that adapt @value{GDBN} to specific hosts and targets. * Porting GDB:: * Testsuite:: * Hints:: +* Index:: @end menu @node Requirements @chapter Requirements +@cindex requirements for @value{GDBN} Before diving into the internals, you should understand the formal -requirements and other expectations for @value{GDBN}. Although some of these may -seem obvious, there have been proposals for @value{GDBN} that have run counter to -these requirements. +requirements and other expectations for @value{GDBN}. Although some +of these may seem obvious, there have been proposals for @value{GDBN} +that have run counter to these requirements. -First of all, @value{GDBN} is a debugger. It's not designed to be a front panel -for embedded systems. It's not a text editor. It's not a shell. It's -not a programming environment. +First of all, @value{GDBN} is a debugger. It's not designed to be a +front panel for embedded systems. It's not a text editor. It's not a +shell. It's not a programming environment. -@value{GDBN} is an interactive tool. Although a batch mode is available, @value{GDBN}'s -primary role is to interact with a human programmer. +@value{GDBN} is an interactive tool. Although a batch mode is +available, @value{GDBN}'s primary role is to interact with a human +programmer. -@value{GDBN} should be responsive to the user. A programmer hot on the trail of -a nasty bug, and operating under a looming deadline, is going to be very -impatient of everything, including the response time to debugger -commands. +@value{GDBN} should be responsive to the user. A programmer hot on +the trail of a nasty bug, and operating under a looming deadline, is +going to be very impatient of everything, including the response time +to debugger commands. -@value{GDBN} should be relatively permissive, such as for expressions. While the -compiler should be picky (or have the option to be made picky), since -source code lives for a long time usually, the programmer doing -debugging shouldn't be spending time figuring out to mollify the -debugger. +@value{GDBN} should be relatively permissive, such as for expressions. +While the compiler should be picky (or have the option to be made +picky), since source code lives for a long time usuazlly, the +programmer doing debugging shouldn't be spending time figuring out to +mollify the debugger. -@value{GDBN} will be called upon to deal with really large programs. Executable -sizes of 50 to 100 megabytes occur regularly, and we've heard reports of -programs approaching 1 gigabyte in size. +@value{GDBN} will be called upon to deal with really large programs. +Executable sizes of 50 to 100 megabytes occur regularly, and we've +heard reports of programs approaching 1 gigabyte in size. -@value{GDBN} should be able to run everywhere. No other debugger is available -for even half as many configurations as @value{GDBN} supports. +@value{GDBN} should be able to run everywhere. No other debugger is +available for even half as many configurations as @value{GDBN} +supports. @node Overall Structure @chapter Overall Structure -@value{GDBN} consists of three major subsystems: user interface, symbol handling -(the ``symbol side''), and target system handling (the ``target side''). +@value{GDBN} consists of three major subsystems: user interface, +symbol handling (the @dfn{symbol side}), and target system handling (the +@dfn{target side}). The user interface consists of several actual interfaces, plus supporting code. @@ -156,16 +164,17 @@ should fit together. @section The Symbol Side -The symbolic side of @value{GDBN} can be thought of as ``everything you can do in -@value{GDBN} without having a live program running''. For instance, you can look -at the types of variables, and evaluate many kinds of expressions. +The symbolic side of @value{GDBN} can be thought of as ``everything +you can do in @value{GDBN} without having a live program running''. +For instance, you can look at the types of variables, and evaluate +many kinds of expressions. @section The Target Side -The target side of @value{GDBN} is the ``bits and bytes manipulator''. Although -it may make reference to symbolic info here and there, most of the -target side will run with only a stripped executable available -- or -even no executable at all, in remote debugging cases. +The target side of @value{GDBN} is the ``bits and bytes manipulator''. +Although it may make reference to symbolic info here and there, most +of the target side will run with only a stripped executable +available---or even no executable at all, in remote debugging cases. Operations such as disassembly, stack frame crawls, and register display, are able to work with no symbolic info at all. In some cases, @@ -175,6 +184,8 @@ way. @section Configurations +@cindex host +@cindex target @dfn{Host} refers to attributes of the system where @value{GDBN} runs. @dfn{Target} refers to the system where the program being debugged executes. In most cases they are the same machine, in which case a @@ -208,25 +219,32 @@ have to include all three kinds of information. @node Algorithms @chapter Algorithms +@cindex algorithms -@value{GDBN} uses a number of debugging-specific algorithms. They are often not -very complicated, but get lost in the thicket of special cases and -real-world issues. This chapter describes the basic algorithms and -mentions some of the specific target definitions that they use. +@value{GDBN} uses a number of debugging-specific algorithms. They are +often not very complicated, but get lost in the thicket of special +cases and real-world issues. This chapter describes the basic +algorithms and mentions some of the specific target definitions that +they use. @section Frames -A frame is a construct that @value{GDBN} uses to keep track of calling and called -functions. +@cindex frame +@cindex call stack frame +A frame is a construct that @value{GDBN} uses to keep track of calling +and called functions. +@findex create_new_frame +@vindex FRAME_FP @code{FRAME_FP} in the machine description has no meaning to the -machine-independent part of @value{GDBN}, except that it is used when setting up -a new frame from scratch, as follows: +machine-independent part of @value{GDBN}, except that it is used when +setting up a new frame from scratch, as follows: @example create_new_frame (read_register (FP_REGNUM), read_pc ())); @end example +@cindex frame pointer register Other than that, all the meaning imparted to @code{FP_REGNUM} is imparted by the machine-dependent code. So, @code{FP_REGNUM} can have any value that is convenient for the code that creates new frames. @@ -234,13 +252,15 @@ any value that is convenient for the code that creates new frames. defined; that is where you should use the @code{FP_REGNUM} value, if your frames are nonstandard.) -Given a @value{GDBN} frame, define @code{FRAME_CHAIN} to determine the address of -the calling function's frame. This will be used to create a new @value{GDBN} -frame struct, and then @code{INIT_EXTRA_FRAME_INFO} and -@code{INIT_FRAME_PC} will be called for the new frame. +@cindex frame chain +Given a @value{GDBN} frame, define @code{FRAME_CHAIN} to determine the +address of the calling function's frame. This will be used to create +a new @value{GDBN} frame struct, and then @code{INIT_EXTRA_FRAME_INFO} +and @code{INIT_FRAME_PC} will be called for the new frame. @section Breakpoint Handling +@cindex breakpoints In general, a breakpoint is a user-designated location in the program where the user wants to regain control if program execution ever reaches that location. @@ -248,35 +268,44 @@ that location. There are two main ways to implement breakpoints; either as ``hardware'' breakpoints or as ``software'' breakpoints. +@cindex hardware breakpoints +@cindex program counter Hardware breakpoints are sometimes available as a builtin debugging features with some chips. Typically these work by having dedicated register into which the breakpoint address may be stored. If the PC +(shorthand for @dfn{program counter}) ever matches a value in a breakpoint registers, the CPU raises an -exception and reports it to @value{GDBN}. Another possibility is when an -emulator is in use; many emulators include circuitry that watches the -address lines coming out from the processor, and force it to stop if the -address matches a breakpoint's address. A third possibility is that the -target already has the ability to do breakpoints somehow; for instance, -a ROM monitor may do its own software breakpoints. So although these -are not literally ``hardware breakpoints'', from @value{GDBN}'s point of view -they work the same; @value{GDBN} need not do nothing more than set the breakpoint -and wait for something to happen. +exception and reports it to @value{GDBN}. + +Another possibility is when an emulator is in use; many emulators +include circuitry that watches the address lines coming out from the +processor, and force it to stop if the address matches a breakpoint's +address. + +A third possibility is that the target already has the ability to do +breakpoints somehow; for instance, a ROM monitor may do its own +software breakpoints. So although these are not literally ``hardware +breakpoints'', from @value{GDBN}'s point of view they work the same; +@value{GDBN} need not do nothing more than set the breakpoint and wait +for something to happen. Since they depend on hardware resources, hardware breakpoints may be -limited in number; when the user asks for more, @value{GDBN} will start trying to -set software breakpoints. - -Software breakpoints require @value{GDBN} to do somewhat more work. The basic -theory is that @value{GDBN} will replace a program instruction with a trap, -illegal divide, or some other instruction that will cause an exception, -and then when it's encountered, @value{GDBN} will take the exception and stop the -program. When the user says to continue, @value{GDBN} will restore the original +limited in number; when the user asks for more, @value{GDBN} will +start trying to set software breakpoints. + +@cindex software breakpoints +Software breakpoints require @value{GDBN} to do somewhat more work. +The basic theory is that @value{GDBN} will replace a program +instruction with a trap, illegal divide, or some other instruction +that will cause an exception, and then when it's encountered, +@value{GDBN} will take the exception and stop the program. When the +user says to continue, @value{GDBN} will restore the original instruction, single-step, re-insert the trap, and continue on. Since it literally overwrites the program being tested, the program area must be writeable, so this technique won't work on programs in ROM. It can also distort the behavior of programs that examine themselves, -although the situation would be highly unusual. +although such a situation would be highly unusual. Also, the software breakpoint instruction should be the smallest size of instruction, so it doesn't overwrite an instruction that might be a jump @@ -289,6 +318,7 @@ set not to have any instructions usable for a software breakpoint, although in practice only the ARC has failed to define such an instruction. +@findex BREAKPOINT The basic definition of the software breakpoint is the macro @code{BREAKPOINT}. @@ -305,16 +335,19 @@ much of the interesting breakpoint action is in @file{infrun.c}. @section Longjmp Support +@cindex @code{longjmp} debugging @value{GDBN} has support for figuring out that the target is doing a @code{longjmp} and for stopping at the target of the jump, if we are stepping. This is done with a few specialized internal breakpoints, -which are visible in the @code{maint info breakpoint} command. +which are visible in the output of the @samp{maint info breakpoint} +command. +@findex GET_LONGJMP_TARGET To make this work, you need to define a macro called @code{GET_LONGJMP_TARGET}, which will examine the @code{jmp_buf} structure and extract the longjmp target address. Since @code{jmp_buf} is target specific, you will need to define it in the appropriate -@file{tm-@var{xyz}.h} file. Look in @file{tm-sun4os4.h} and +@file{tm-@var{target}.h} file. Look in @file{tm-sun4os4.h} and @file{sparc-tdep.c} for examples of how to do this. @node User Interface @@ -326,20 +359,25 @@ is the most common and most familiar, there are others. @section Command Interpreter +@cindex command interpreter The command interpreter in @value{GDBN} is fairly simple. It is designed to allow for the set of commands to be augmented dynamically, and also has a recursive subcommand capability, where the first argument to a command may itself direct a lookup on a different command list. -For instance, the @code{set} command just starts a lookup on the -@code{setlist} command list, while @code{set thread} recurses +For instance, the @samp{set} command just starts a lookup on the +@code{setlist} command list, while @samp{set thread} recurses to the @code{set_thread_cmd_list}. +@findex add_cmd +@findex add_com To add commands in general, use @code{add_cmd}. @code{add_com} adds to the main command list, and should be used for those commands. The usual place to add commands is in the @code{_initialize_@var{xyz}} routines at the ends of most source files. +@cindex deprecating commands +@findex deprecate_cmd Before removing commands from the command set it is a good idea to deprecate them for some time. Use @code{deprecate_cmd} on commands or aliases to set the deprecated flag. @code{deprecate_cmd} takes a @@ -358,6 +396,7 @@ entire string the user should type at the command line. @section libgdb +@cindex @code{libgdb} @code{libgdb} was an abortive project of years ago. The theory was to provide an API to @value{GDBN}'s functionality. @@ -370,23 +409,31 @@ functions, and types. @section Symbol Reading -@value{GDBN} reads symbols from ``symbol files''. The usual symbol file is the -file containing the program which @value{GDBN} is debugging. @value{GDBN} can be directed -to use a different file for symbols (with the @code{symbol-file} -command), and it can also read more symbols via the ``add-file'' and -``load'' commands, or while reading symbols from shared libraries. - -Symbol files are initially opened by code in @file{symfile.c} using the -BFD library. BFD identifies the type of the file by examining its -header. @code{find_sym_fns} then uses this identification to locate a -set of symbol-reading functions. - -Symbol reading modules identify themselves to @value{GDBN} by calling +@cindex symbol reading +@cindex reading of symbols +@cindex symbol files +@value{GDBN} reads symbols from @dfn{symbol files}. The usual symbol +file is the file containing the program which @value{GDBN} is +debugging. @value{GDBN} can be directed to use a different file for +symbols (with the @samp{symbol-file} command), and it can also read +more symbols via the @samp{add-file} and @samp{load} commands, or while +reading symbols from shared libraries. + +@findex find_sym_fns +Symbol files are initially opened by code in @file{symfile.c} using +the BFD library (@pxref{Support Libraries}). BFD identifies the type +of the file by examining its header. @code{find_sym_fns} then uses +this identification to locate a set of symbol-reading functions. + +@findex add_symtab_fns +@cindex @code{sym_fns} structure +@cindex adding a symbol-reading module +Symbol-reading modules identify themselves to @value{GDBN} by calling @code{add_symtab_fns} during their module initialization. The argument to @code{add_symtab_fns} is a @code{struct sym_fns} which contains the name (or name prefix) of the symbol format, the length of the prefix, and pointers to four functions. These functions are called at various -times to process symbol-files whose identification matches the specified +times to process symbol files whose identification matches the specified prefix. The functions supplied by each module are: @@ -394,11 +441,12 @@ The functions supplied by each module are: @table @code @item @var{xyz}_symfile_init(struct sym_fns *sf) +@cindex secondary symbol file Called from @code{symbol_file_add} when we are about to read a new symbol file. This function should clean up any internal state (possibly resulting from half-read previous files, for example) and prepare to -read a new symbol file. Note that the symbol file which we are reading -might be a new "main" symbol file, or might be a secondary symbol file +read a new symbol file. Note that the symbol file which we are reading +might be a new ``main'' symbol file, or might be a secondary symbol file whose symbols are being added to the existing symbol table. The argument to @code{@var{xyz}_symfile_init} is a newly allocated @@ -414,19 +462,19 @@ There is no result from @code{@var{xyz}_symfile_init}, but it can call @item @var{xyz}_new_init() Called from @code{symbol_file_add} when discarding existing symbols. -This function need only handle the symbol-reading module's internal -state; the symbol table data structures visible to the rest of @value{GDBN} will -be discarded by @code{symbol_file_add}. It has no arguments and no -result. It may be called after @code{@var{xyz}_symfile_init}, if a new -symbol table is being read, or may be called alone if all symbols are -simply being discarded. +This function needs only handle the symbol-reading module's internal +state; the symbol table data structures visible to the rest of +@value{GDBN} will be discarded by @code{symbol_file_add}. It has no +arguments and no result. It may be called after +@code{@var{xyz}_symfile_init}, if a new symbol table is being read, or +may be called alone if all symbols are simply being discarded. @item @var{xyz}_symfile_read(struct sym_fns *sf, CORE_ADDR addr, int mainline) Called from @code{symbol_file_add} to actually read the symbols from a symbol-file into a set of psymtabs or symtabs. -@code{sf} points to the struct sym_fns originally passed to +@code{sf} points to the @code{struct sym_fns} originally passed to @code{@var{xyz}_sym_init} for possible initialization. @code{addr} is the offset between the file's specified start address and its true address in memory. @code{mainline} is 1 if this is the main symbol @@ -442,37 +490,44 @@ from any point in the @value{GDBN} symbol-handling code. @table @code @item @var{xyz}_psymtab_to_symtab (struct partial_symtab *pst) -Called from @code{psymtab_to_symtab} (or the PSYMTAB_TO_SYMTAB macro) if +Called from @code{psymtab_to_symtab} (or the @code{PSYMTAB_TO_SYMTAB} macro) if the psymtab has not already been read in and had its @code{pst->symtab} pointer set. The argument is the psymtab to be fleshed-out into a -symtab. Upon return, pst->readin should have been set to 1, and -pst->symtab should contain a pointer to the new corresponding symtab, or +symtab. Upon return, @code{pst->readin} should have been set to 1, and +@code{pst->symtab} should contain a pointer to the new corresponding symtab, or zero if there were no symbols in that part of the symbol file. @end table @section Partial Symbol Tables -@value{GDBN} has three types of symbol tables. +@value{GDBN} has three types of symbol tables: @itemize @bullet +@cindex full symbol table +@cindex symtabs +@item +Full symbol tables (@dfn{symtabs}). These contain the main +information about symbols and addresses. -@item full symbol tables (symtabs). These contain the main information -about symbols and addresses. - -@item partial symbol tables (psymtabs). These contain enough +@cindex psymtabs +@item +Partial symbol tables (@dfn{psymtabs}). These contain enough information to know when to read the corresponding part of the full symbol table. -@item minimal symbol tables (msymtabs). These contain information +@cindex minimal symbol table +@cindex minsymtabs +@item +Minimal symbol tables (@dfn{msymtabs}). These contain information gleaned from non-debugging symbols. - @end itemize +@cindex partial symbol table This section describes partial symbol tables. A psymtab is constructed by doing a very quick pass over an executable file's debugging information. Small amounts of information are -extracted -- enough to identify which parts of the symbol table will +extracted---enough to identify which parts of the symbol table will need to be re-read and fully digested later, when the user needs the information. The speed of this pass causes @value{GDBN} to start up very quickly. Later, as the detailed rereading occurs, it occurs in small @@ -483,33 +538,37 @@ the user. The symbols that show up in a file's psymtab should be, roughly, those visible to the debugger's user when the program is not running code from that file. These include external symbols and types, static symbols and -types, and enum values declared at file scope. +types, and @code{enum} values declared at file scope. The psymtab also contains the range of instruction addresses that the full symbol table would represent. +@cindex finding a symbol +@cindex symbol lookup The idea is that there are only two ways for the user (or much of the code in the debugger) to reference a symbol: @itemize @bullet +@findex find_pc_function +@findex find_pc_line +@item +By its address (e.g. execution stops at some address which is inside a +function in this file). The address will be noticed to be in the +range of this psymtab, and the full symtab will be read in. +@code{find_pc_function}, @code{find_pc_line}, and other +@code{find_pc_@dots{}} functions handle this. -@item by its address -(e.g. execution stops at some address which is inside a function in this -file). The address will be noticed to be in the range of this psymtab, -and the full symtab will be read in. @code{find_pc_function}, -@code{find_pc_line}, and other @code{find_pc_@dots{}} functions handle -this. - -@item by its name +@cindex lookup_symbol +@item +By its name (e.g. the user asks to print a variable, or set a breakpoint on a function). Global names and file-scope names will be found in the psymtab, which will cause the symtab to be pulled in. Local names will have to be qualified by a global name, or a file-scope name, in which case we will have already read in the symtab as we evaluated the -qualifier. Or, a local symbol can be referenced when we are "in" a +qualifier. Or, a local symbol can be referenced when we are ``in'' a local scope, in which case the first case applies. @code{lookup_symbol} does most of the work here. - @end itemize The only reason that psymtabs exist is to cause a symtab to be read in @@ -520,12 +579,13 @@ them anyway. Psymtabs don't have the idea of the type of a symbol, either, so types need not appear, unless they will be referenced by name. -It is a bug for @value{GDBN} to behave one way when only a psymtab has been read, -and another way if the corresponding symtab has been read in. Such bugs -are typically caused by a psymtab that does not contain all the visible -symbols, or which has the wrong instruction address ranges. +It is a bug for @value{GDBN} to behave one way when only a psymtab has +been read, and another way if the corresponding symtab has been read +in. Such bugs are typically caused by a psymtab that does not contain +all the visible symbols, or which has the wrong instruction address +ranges. -The psymtab for a particular section of a symbol-file (objfile) could be +The psymtab for a particular section of a symbol file (objfile) could be thrown away after the symtab has been read in. The symtab should always be searched before the psymtab, so the psymtab will never be used (in a bug-free environment). Currently, psymtabs are allocated on an obstack, @@ -535,52 +595,62 @@ unless you want to do a lot more work. @section Types -Fundamental Types (e.g., FT_VOID, FT_BOOLEAN). +@unnumberedsubsec Fundamental Types (e.g., @code{FT_VOID}, @code{FT_BOOLEAN}). +@cindex fundamental types These are the fundamental types that @value{GDBN} uses internally. Fundamental types from the various debugging formats (stabs, ELF, etc) are mapped into one of these. They are basically a union of all fundamental types -that gdb knows about for all the languages that @value{GDBN} knows about. +that @value{GDBN} knows about for all the languages that @value{GDBN} +knows about. -Type Codes (e.g., TYPE_CODE_PTR, TYPE_CODE_ARRAY). +@unnumberedsubsec Type Codes (e.g., @code{TYPE_CODE_PTR}, @code{TYPE_CODE_ARRAY}). -Each time @value{GDBN} builds an internal type, it marks it with one of these -types. The type may be a fundamental type, such as TYPE_CODE_INT, or a -derived type, such as TYPE_CODE_PTR which is a pointer to another type. -Typically, several FT_* types map to one TYPE_CODE_* type, and are -distinguished by other members of the type struct, such as whether the -type is signed or unsigned, and how many bits it uses. +@cindex type codes +Each time @value{GDBN} builds an internal type, it marks it with one +of these types. The type may be a fundamental type, such as +@code{TYPE_CODE_INT}, or a derived type, such as @code{TYPE_CODE_PTR} +which is a pointer to another type. Typically, several @code{FT_*} +types map to one @code{TYPE_CODE_*} type, and are distinguished by +other members of the type struct, such as whether the type is signed +or unsigned, and how many bits it uses. -Builtin Types (e.g., builtin_type_void, builtin_type_char). +@unnumberedsubsec Builtin Types (e.g., @code{builtin_type_void}, @code{builtin_type_char}). These are instances of type structs that roughly correspond to -fundamental types and are created as global types for @value{GDBN} to use for -various ugly historical reasons. We eventually want to eliminate these. -Note for example that builtin_type_int initialized in gdbtypes.c is -basically the same as a TYPE_CODE_INT type that is initialized in -c-lang.c for an FT_INTEGER fundamental type. The difference is that the -builtin_type is not associated with any particular objfile, and only one -instance exists, while c-lang.c builds as many TYPE_CODE_INT types as -needed, with each one associated with some particular objfile. +fundamental types and are created as global types for @value{GDBN} to +use for various ugly historical reasons. We eventually want to +eliminate these. Note for example that @code{builtin_type_int} +initialized in @file{gdbtypes.c} is basically the same as a +@code{TYPE_CODE_INT} type that is initialized in @file{c-lang.c} for +an @code{FT_INTEGER} fundamental type. The difference is that the +@code{builtin_type} is not associated with any particular objfile, and +only one instance exists, while @file{c-lang.c} builds as many +@code{TYPE_CODE_INT} types as needed, with each one associated with +some particular objfile. @section Object File Formats +@cindex object file formats @subsection a.out -The @file{a.out} format is the original file format for Unix. It -consists of three sections: text, data, and bss, which are for program -code, initialized data, and uninitialized data, respectively. +@cindex @code{a.out} format +The @code{a.out} format is the original file format for Unix. It +consists of three sections: @code{text}, @code{data}, and @code{bss}, +which are for program code, initialized data, and uninitialized data, +respectively. -The @file{a.out} format is so simple that it doesn't have any reserved +The @code{a.out} format is so simple that it doesn't have any reserved place for debugging information. (Hey, the original Unix hackers used -@file{adb}, which is a machine-language debugger.) The only debugging -format for @file{a.out} is stabs, which is encoded as a set of normal +@samp{adb}, which is a machine-language debugger!) The only debugging +format for @code{a.out} is stabs, which is encoded as a set of normal symbols with distinctive attributes. -The basic @file{a.out} reader is in @file{dbxread.c}. +The basic @code{a.out} reader is in @file{dbxread.c}. @subsection COFF +@cindex COFF format The COFF format was introduced with System V Release 3 (SVR3) Unix. COFF files may have multiple sections, each prefixed by a header. The number of sections is limited. @@ -594,6 +664,7 @@ The COFF reader is in @file{coffread.c}. @subsection ECOFF +@cindex ECOFF format ECOFF is an extended COFF originally introduced for Mips and Alpha workstations. @@ -601,11 +672,12 @@ The basic ECOFF reader is in @file{mipsread.c}. @subsection XCOFF +@cindex XCOFF format The IBM RS/6000 running AIX uses an object file format called XCOFF. The COFF sections, symbols, and line numbers are used, but debugging -symbols are dbx-style stabs whose strings are located in the -@samp{.debug} section (rather than the string table). For more -information, see @xref{Top,,,stabs,The Stabs Debugging Format}. +symbols are @code{dbx}-style stabs whose strings are located in the +@code{.debug} section (rather than the string table). For more +information, see @ref{Top,,,stabs,The Stabs Debugging Format}. The shared library scheme has a clean interface for figuring out what shared libraries are in use, but the catch is that everything which @@ -616,7 +688,8 @@ been run (or the core file has been read). @subsection PE -Windows 95 and NT use the PE (Portable Executable) format for their +@cindex PE-COFF format +Windows 95 and NT use the PE (@dfn{Portable Executable}) format for their executables. PE is basically COFF with additional headers. While BFD includes special PE support, @value{GDBN} needs only the basic @@ -624,6 +697,7 @@ COFF reader. @subsection ELF +@cindex ELF format The ELF format came with System V Release 4 (SVR4) Unix. ELF is similar to COFF in being organized into a number of sections, but it removes many of COFF's limitations. @@ -632,6 +706,7 @@ The basic ELF reader is in @file{elfread.c}. @subsection SOM +@cindex SOM format SOM is HP's object file and debug format (not to be confused with IBM's SOM, which is a cross-language ABI). @@ -639,6 +714,7 @@ The SOM reader is in @file{hpread.c}. @subsection Other File Formats +@cindex Netware Loadable Module format Other file formats that have been supported by @value{GDBN} include Netware Loadable Modules (@file{nlmread.c}. @@ -649,6 +725,7 @@ are independent of the object file format. @subsection stabs +@cindex stabs debugging info @code{stabs} started out as special symbols within the @code{a.out} format. Since then, it has been encapsulated into other file formats, such as COFF and ELF. @@ -659,17 +736,20 @@ the real work. @subsection COFF +@cindex COFF debugging info The basic COFF definition includes debugging information. The level of support is minimal and non-extensible, and is not often used. @subsection Mips debug (Third Eye) +@cindex ECOFF debugging info ECOFF includes a definition of a special debug format. The file @file{mdebugread.c} implements reading for this format. @subsection DWARF 1 +@cindex DWARF 1 debugging info DWARF 1 is a debugging format that was originally designed to be used with ELF in SVR4 systems. @@ -684,17 +764,20 @@ The DWARF 1 reader is in @file{dwarfread.c}. @subsection DWARF 2 +@cindex DWARF 2 debugging info DWARF 2 is an improved but incompatible version of DWARF 1. The DWARF 2 reader is in @file{dwarf2read.c}. @subsection SOM +@cindex SOM debugging info Like COFF, the SOM definition includes debugging information. @section Adding a New Symbol Reader to @value{GDBN} -If you are using an existing object file format (a.out, COFF, ELF, etc), +@cindex adding debugging info reader +If you are using an existing object file format (@code{a.out}, COFF, ELF, etc), there is probably little to be done. If you need to add a new object file format, you must first add it to @@ -711,55 +794,60 @@ to call swapping routines, since the external data structures on various platforms have different sizes and layouts. Specialized routines that will only ever be implemented by one object file format may be called directly. This interface should be described in a file -@file{bfd/libxyz.h}, which is included by @value{GDBN}. +@file{bfd/lib@var{xyz}.h}, which is included by @value{GDBN}. @node Language Support @chapter Language Support -@value{GDBN}'s language support is mainly driven by the symbol reader, although -it is possible for the user to set the source language manually. +@cindex language support +@value{GDBN}'s language support is mainly driven by the symbol reader, +although it is possible for the user to set the source language +manually. -@value{GDBN} chooses the source language by looking at the extension of the file -recorded in the debug info; @code{.c} means C, @code{.f} means Fortran, -etc. It may also use a special-purpose language identifier if the debug -format supports it, such as DWARF. +@value{GDBN} chooses the source language by looking at the extension +of the file recorded in the debug info; @file{.c} means C, @file{.f} +means Fortran, etc. It may also use a special-purpose language +identifier if the debug format supports it, like with DWARF. @section Adding a Source Language to @value{GDBN} -To add other languages to @value{GDBN}'s expression parser, follow the following -steps: +@cindex adding source language +To add other languages to @value{GDBN}'s expression parser, follow the +following steps: @table @emph @item Create the expression parser. +@cindex expression parser This should reside in a file @file{@var{lang}-exp.y}. Routines for -building parsed expressions into a @samp{union exp_element} list are in +building parsed expressions into a @code{union exp_element} list are in @file{parse.c}. +@cindex language parser Since we can't depend upon everyone having Bison, and YACC produces parsers that define a bunch of global names, the following lines -@emph{must} be included at the top of the YACC parser, to prevent the +@strong{must} be included at the top of the YACC parser, to prevent the various parsers from defining the same global names: @example -#define yyparse @var{lang}_parse -#define yylex @var{lang}_lex -#define yyerror @var{lang}_error -#define yylval @var{lang}_lval -#define yychar @var{lang}_char -#define yydebug @var{lang}_debug -#define yypact @var{lang}_pact -#define yyr1 @var{lang}_r1 -#define yyr2 @var{lang}_r2 -#define yydef @var{lang}_def -#define yychk @var{lang}_chk -#define yypgo @var{lang}_pgo -#define yyact @var{lang}_act -#define yyexca @var{lang}_exca -#define yyerrflag @var{lang}_errflag -#define yynerrs @var{lang}_nerrs +#define yyparse @var{lang}_parse +#define yylex @var{lang}_lex +#define yyerror @var{lang}_error +#define yylval @var{lang}_lval +#define yychar @var{lang}_char +#define yydebug @var{lang}_debug +#define yypact @var{lang}_pact +#define yyr1 @var{lang}_r1 +#define yyr2 @var{lang}_r2 +#define yydef @var{lang}_def +#define yychk @var{lang}_chk +#define yypgo @var{lang}_pgo +#define yyact @var{lang}_act +#define yyexca @var{lang}_exca +#define yyerrflag @var{lang}_errflag +#define yynerrs @var{lang}_nerrs @end example At the bottom of your parser, define a @code{struct language_defn} and @@ -774,11 +862,16 @@ for more information. @item Add any evaluation routines, if necessary +@cindex expression evaluation routines +@findex evaluate_subexp +@findex prefixify_subexp +@findex length_of_subexp If you need new opcodes (that represent the operations of the language), add them to the enumerated type in @file{expression.h}. Add support -code for these operations in @code{eval.c:evaluate_subexp()}. Add cases +code for these operations in the @code{evaluate_subexp} function +defined in the file @file{eval.c}. Add cases for new opcodes in two functions from @file{parse.c}: -@code{prefixify_subexp()} and @code{length_of_subexp()}. These compute +@code{prefixify_subexp} and @code{length_of_subexp}. These compute the number of @code{exp_element}s that a given operation takes up. @item Update some existing code @@ -791,15 +884,18 @@ These routines include type predicates and such, which (in some cases) are language dependent. If your language does not appear in the switch statement, an error is reported. +@vindex current_language Also included in @file{language.c} is the code that updates the variable @code{current_language}, and the routines that translate the @code{language_@var{lang}} enumerated identifier into a printable string. +@findex _initialize_language Update the function @code{_initialize_language} to include your language. This function picks the default language upon startup, so is dependent upon which languages that @value{GDBN} is built for. +@findex allocate_symtab Update @code{allocate_symtab} in @file{symfile.c} and/or symbol-reading code so that the language of each symtab (source file) is set properly. This is used to determine the language to use at each stack frame level. @@ -808,17 +904,21 @@ file. If the language can be better inferred from the symbol information, please set the language of the symtab in the symbol-reading code. -Add helper code to @code{expprint.c:print_subexp()} to handle any new +@findex print_subexp +@findex op_print_tab +Add helper code to @code{print_subexp} (in @file{expprint.c}) to handle any new expression opcodes you have added to @file{expression.h}. Also, add the printed representations of your operators to @code{op_print_tab}. @item Add a place of call +@findex parse_exp_1 Add a call to @code{@var{lang}_parse()} and @code{@var{lang}_error} in -@code{parse.c:parse_exp_1()}. +@code{parse_exp_1} (defined in @file{parse.c}). @item Use macros to trim code +@cindex trimming language-dependent code The user has the option of building @value{GDBN} for some or all of the languages. If the user decides to build @value{GDBN} for the language @var{lang}, then every file dependent on @file{language.h} will have the @@ -830,8 +930,8 @@ Note that you do not need to do this in your YACC parser, since if @value{GDBN} is not build for @var{lang}, then @file{@var{lang}-exp.tab.o} (the compiled form of your parser) is not linked into @value{GDBN} at all. -See the file @file{configure.in} for how @value{GDBN} is configured for different -languages. +See the file @file{configure.in} for how @value{GDBN} is configured +for different languages. @item Edit @file{Makefile.in} @@ -839,7 +939,6 @@ Add dependencies in @file{Makefile.in}. Make sure you update the macro variables such as @code{HFILES} and @code{OBJS}, otherwise your code may not get linked in, or, worse yet, it may not get @code{tar}red into the distribution! - @end table @@ -847,20 +946,23 @@ distribution! @chapter Host Definition -With the advent of autoconf, it's rarely necessary to have host +With the advent of Autoconf, it's rarely necessary to have host definition machinery anymore. @section Adding a New Host -Most of @value{GDBN}'s host configuration support happens via autoconf. It -should be rare to need new host-specific definitions. @value{GDBN} still uses -the host-specific definitions and files listed below, but these mostly -exist for historical reasons, and should eventually disappear. +@cindex adding a new host +@cindex host, adding +Most of @value{GDBN}'s host configuration support happens via +Autoconf. New host-specific definitions should be rarely needed. +@value{GDBN} still uses the host-specific definitions and files listed +below, but these mostly exist for historical reasons, and should +eventually disappear. Several files control @value{GDBN}'s configuration for host systems: @table @file - +@vindex XDEPFILES @item gdb/config/@var{arch}/@var{xyz}.mh Specifies Makefile fragments needed when hosting on machine @var{xyz}. In particular, this lists the required machine-dependent object files, @@ -871,7 +973,7 @@ xm-@var{xyz}.h}. You can also define @code{CC}, @code{SYSV_DEFINE}, etc.; see @file{Makefile.in}. @item gdb/config/@var{arch}/xm-@var{xyz}.h -(@file{xm.h} is a link to this file, created by configure). Contains C +(@file{xm.h} is a link to this file, created by @code{configure}). Contains C macro definitions describing the host system environment, such as byte order, host C compiler and library. @@ -880,11 +982,11 @@ Contains any miscellaneous C code required for this machine as a host. On most machines it doesn't exist at all. If it does exist, put @file{@var{xyz}-xdep.o} into the @code{XDEPFILES} line in @file{gdb/config/@var{arch}/@var{xyz}.mh}. - @end table @subheading Generic Host Support Files +@cindex generic host support There are some ``generic'' versions of routines that can be used by various systems. These can be customized in various ways by macros defined in your @file{xm-@var{xyz}.h} file. If these routines work for @@ -897,7 +999,8 @@ Put them into @code{@var{xyz}-xdep.c}, and put @code{@var{xyz}-xdep.o} into @code{XDEPFILES}. @table @file - +@cindex remote debugging support +@cindex serial line support @item ser-unix.c This contains serial line support for Unix systems. This is always included, via the makefile variable @code{SER_HARDWIRE}; override this @@ -905,25 +1008,25 @@ variable in the @file{.mh} file to avoid it. @item ser-go32.c This contains serial line support for 32-bit programs running under DOS, -using the GO32 execution environment. +using the DJGPP (a.k.a.@: GO32) execution environment. +@cindex TCP remote support @item ser-tcp.c This contains generic TCP support using sockets. - @end table @section Host Conditionals -When @value{GDBN} is configured and compiled, various macros are defined or left -undefined, to control compilation based on the attributes of the host -system. These macros and their meanings (or if the meaning is not -documented here, then one of the source files where they are used is -indicated) are: - -@table @code +When @value{GDBN} is configured and compiled, various macros are +defined or left undefined, to control compilation based on the +attributes of the host system. These macros and their meanings (or if +the meaning is not documented here, then one of the source files where +they are used is indicated) are: +@ftable @code @item @value{GDBN}INIT_FILENAME -The default name of @value{GDBN}'s initialization file (normally @file{.gdbinit}). +The default name of @value{GDBN}'s initialization file (normally +@file{.gdbinit}). @item MEM_FNS_DECLARED Your host config file defines this if it includes declarations of @@ -945,22 +1048,26 @@ Define this to expand into code that will define the function named by the expansion of @code{SIGWINCH_HANDLER}. @item ALIGN_STACK_ON_STARTUP +@cindex stack alignment Define this if your system is of a sort that will crash in @code{tgetent} if the stack happens not to be longword-aligned when @code{main} is called. This is a rare situation, but is known to occur on several different types of systems. @item CRLF_SOURCE_FILES +@cindex DOS text files Define this if host files use @code{\r\n} rather than @code{\n} as a line terminator. This will cause source file listings to omit @code{\r} -characters when printing and it will allow \r\n line endings of files -which are "sourced" by gdb. It must be possible to open files in binary +characters when printing and it will allow @code{\r\n} line endings of files +which are ``sourced'' by gdb. It must be possible to open files in binary mode using @code{O_BINARY} or, for fopen, @code{"rb"}. @item DEFAULT_PROMPT +@cindex prompt The default value of the prompt string (normally @code{"(gdb) "}). @item DEV_TTY +@cindex terminal device The name of the generic TTY device, defaults to @code{"/dev/tty"}. @item FCLOSE_PROVIDED @@ -973,21 +1080,24 @@ Define this if binary files are opened the same way as text files. @item GETENV_PROVIDED Define this if the system declares @code{getenv} in its headers included -in @code{defs.h}. This isn't needed unless your compiler is unusually +in @code{defs.h}. This isn't needed unless your compiler is unusually anal. @item HAVE_MMAP +@findex mmap In some cases, use the system call @code{mmap} for reading symbol tables. For some machines this allows for sharing and quick updates. @item HAVE_SIGSETMASK +@findex sigsetmask Define this if the host system has job control, but does not define -@code{sigsetmask()}. Currently, this is only true of the RS/6000. +@code{sigsetmask}. Currently, this is only true of the RS/6000. @item HAVE_TERMIO Define this if the host system has @code{termio.h}. @item HOST_BYTE_ORDER +@cindex byte order The ordering of bytes in the host. This must be defined to be either @code{BIG_ENDIAN} or @code{LITTLE_ENDIAN}. @@ -1007,26 +1117,28 @@ it will default to @code{long long} or @code{long}, depending on @code{CC_HAS_LONG_LONG}. @item CC_HAS_LONG_LONG -Define this if the host C compiler supports ``long long''. This is set -by the configure script. +@cindex @code{long long} data type +Define this if the host C compiler supports @code{long long}. This is set +by the @code{configure} script. @item PRINTF_HAS_LONG_LONG Define this if the host can handle printing of long long integers via -the printf format directive ``ll''. This is set by the configure script. +the printf format conversion specifier @code{ll}. This is set by the +@code{configure} script. @item HAVE_LONG_DOUBLE -Define this if the host C compiler supports ``long double''. This is -set by the configure script. +Define this if the host C compiler supports @code{long double}. This is +set by the @code{configure} script. @item PRINTF_HAS_LONG_DOUBLE Define this if the host can handle printing of long double float-point -numbers via the printf format directive ``Lg''. This is set by the -configure script. +numbers via the printf format conversion specifier @code{Lg}. This is +set by the @code{configure} script. @item SCANF_HAS_LONG_DOUBLE Define this if the host can handle the parsing of long double -float-point numbers via the scanf format directive directive -``Lg''. This is set by the configure script. +float-point numbers via the scanf format conversion specifier +@code{Lg}. This is set by the @code{configure} script. @item LSEEK_NOT_LINEAR Define this if @code{lseek (n)} does not necessarily move to byte number @@ -1034,13 +1146,13 @@ Define this if @code{lseek (n)} does not necessarily move to byte number is normally faster to define @code{CRLF_SOURCE_FILES} when possible. @item L_SET -This macro is used as the argument to lseek (or, most commonly, -bfd_seek). FIXME, should be replaced by SEEK_SET instead, which is the -POSIX equivalent. +This macro is used as the argument to @code{lseek} (or, most commonly, +@code{bfd_seek}). FIXME, should be replaced by SEEK_SET instead, +which is the POSIX equivalent. @item MALLOC_INCOMPATIBLE Define this if the system's prototype for @code{malloc} differs from the -@sc{ANSI} definition. +@sc{ansi} definition. @item MMAP_BASE_ADDRESS When using HAVE_MMAP, the first mapping should go at this address. @@ -1049,6 +1161,7 @@ When using HAVE_MMAP, the first mapping should go at this address. when using HAVE_MMAP, this is the increment between mappings. @item NEED_POSIX_SETPGID +@findex setpgid Define this to use the POSIX version of @code{setpgid} to determine whether job control is available. @@ -1066,27 +1179,30 @@ set correctly if compiling with GCC. This will almost never need to be defined. @item USE_GENERIC_DUMMY_FRAMES +@cindex generic dummy frames Define this to 1 if the target is using the generic inferior function call code. See @code{blockframe.c} for more information. @item USE_MMALLOC -@value{GDBN} will use the @code{mmalloc} library for memory allocation for symbol -reading if this symbol is defined. Be careful defining it since there -are systems on which @code{mmalloc} does not work for some reason. One -example is the DECstation, where its RPC library can't cope with our -redefinition of @code{malloc} to call @code{mmalloc}. When defining -@code{USE_MMALLOC}, you will also have to set @code{MMALLOC} in the -Makefile, to point to the mmalloc library. This define is set when you -configure with --with-mmalloc. +@findex mmalloc +@value{GDBN} will use the @code{mmalloc} library for memory allocation +for symbol reading if this symbol is defined. Be careful defining it +since there are systems on which @code{mmalloc} does not work for some +reason. One example is the DECstation, where its RPC library can't +cope with our redefinition of @code{malloc} to call @code{mmalloc}. +When defining @code{USE_MMALLOC}, you will also have to set +@code{MMALLOC} in the Makefile, to point to the @code{mmalloc} library. This +define is set when you configure with @samp{--with-mmalloc}. @item NO_MMCHECK +@findex mmcheck Define this if you are using @code{mmalloc}, but don't want the overhead of checking the heap with @code{mmcheck}. Note that on some systems, -the C runtime makes calls to malloc prior to calling @code{main}, and if +the C runtime makes calls to @code{malloc} prior to calling @code{main}, and if @code{free} is ever called with these pointers after calling @code{mmcheck} to enable checking, a memory corruption abort is certain -to occur. These systems can still use mmalloc, but must define -NO_MMCHECK. +to occur. These systems can still use @code{mmalloc}, but must define +@code{NO_MMCHECK}. @item MMCHECK_FORCE Define this to 1 if the C runtime allocates memory prior to @@ -1094,27 +1210,28 @@ Define this to 1 if the C runtime allocates memory prior to have to worry about it triggering a memory corruption abort. The default is 0, which means that @code{mmcheck} will only install the heap checking functions if there has not yet been any memory allocation -calls, and if it fails to install the functions, gdb will issue a +calls, and if it fails to install the functions, @value{GDBN} will issue a warning. This is currently defined if you configure using ---with-mmalloc. +@samp{--with-mmalloc}. @item NO_SIGINTERRUPT -Define this to indicate that siginterrupt() is not available. +@findex siginterrupt +Define this to indicate that @code{siginterrupt} is not available. @item R_OK -Define if this is not in a system .h file. +Define if this is not in a system header file (typically, @file{unistd.h}). @item SEEK_CUR @item SEEK_SET -Define these to appropriate value for the system lseek(), if not already +Define these to appropriate value for the system @code{lseek}, if not already defined. @item STOP_SIGNAL -This is the signal for stopping @value{GDBN}. Defaults to SIGTSTP. (Only -redefined for the Convex.) +This is the signal for stopping @value{GDBN}. Defaults to +@code{SIGTSTP}. (Only redefined for the Convex.) @item USE_O_NOCTTY -Define this if the interior's tty should be opened with the O_NOCTTY +Define this if the interior's tty should be opened with the @code{O_NOCTTY} flag. (FIXME: This should be a native-only flag, but @file{inflow.c} is always linked in.) @@ -1125,36 +1242,37 @@ This symbol is abused in @file{infrun.c}, @file{regex.c}, moment.) @item lint -Define this to help placate lint in some situations. +Define this to help placate @code{lint} in some situations. @item volatile Define this to override the defaults of @code{__volatile__} or @code{/**/}. - -@end table +@end ftable @node Target Architecture Definition @chapter Target Architecture Definition -@value{GDBN}'s target architecture defines what sort of machine-language programs -@value{GDBN} can work with, and how it works with them. +@cindex target architecture definition +@value{GDBN}'s target architecture defines what sort of +machine-language programs @value{GDBN} can work with, and how it works +with them. At present, the target architecture definition consists of a number of C macros. @section Registers and Memory -@value{GDBN}'s model of the target machine is rather simple. @value{GDBN} assumes the -machine includes a bank of registers and a block of memory. Each -register may have a different size. +@value{GDBN}'s model of the target machine is rather simple. +@value{GDBN} assumes the machine includes a bank of registers and a +block of memory. Each register may have a different size. -@value{GDBN} does not have a magical way to match up with the compiler's idea of -which registers are which; however, it is critical that they do match up -accurately. The only way to make this work is to get accurate -information about the order that the compiler uses, and to reflect that -in the @code{REGISTER_NAME} and related macros. +@value{GDBN} does not have a magical way to match up with the +compiler's idea of which registers are which; however, it is critical +that they do match up accurately. The only way to make this work is +to get accurate information about the order that the compiler uses, +and to reflect that in the @code{REGISTER_NAME} and related macros. @value{GDBN} can handle big-endian, little-endian, and bi-endian architectures. @@ -1172,7 +1290,7 @@ in the @code{REGISTER_NAME} and related macros. On almost all 32-bit architectures, the representation of a pointer is indistinguishable from the representation of some fixed-length number whose value is the byte address of the object pointed to. On such -machines, the words `pointer' and `address' can be used interchangeably. +machines, the words ``pointer'' and ``address'' can be used interchangeably. However, architectures with smaller word sizes are often cramped for address space, so they may choose a pointer representation that breaks this identity, and allows a larger code address space. @@ -1185,9 +1303,9 @@ full 32 bit instructions, which is what matters in this explanation.}. If the D10V used ordinary byte addresses to refer to code locations, then the processor would only be able to address 64kb of instructions. However, since instructions must be aligned on four-byte boundaries, the -low two bits of any valid instruction's byte address are always zero --- -byte addresses waste two bits. So instead of byte addresses, the D10V -uses word addresses --- byte addresses shifted right two bits --- to +low two bits of any valid instruction's byte address are always +zero---byte addresses waste two bits. So instead of byte addresses, +the D10V uses word addresses---byte addresses shifted right two bits---to refer to code. Thus, the D10V can use 16-bit words to address 256kb of code space. @@ -1200,8 +1318,8 @@ forms on the D10V. The 16-bit word @code{0xC020} refers to byte address affects the correspondence between pointers and addresses, but we're going to ignore that here; this example is already too long.) -To cope with architectures like this --- the D10V is not the only one! ---- @value{GDBN} tries to distinguish between @dfn{addresses}, which are +To cope with architectures like this---the D10V is not the only +one!---@value{GDBN} tries to distinguish between @dfn{addresses}, which are byte numbers, and @dfn{pointers}, which are the target's representation of an address of a particular type of data. In the example above, @code{0xC020} is the pointer, which refers to one of the addresses @@ -1307,7 +1425,7 @@ appropriate format for the current architecture. Return the byte address the pointer refers to. This function may safely assume that @var{type} is either a pointer or a -C++ reference type. +C@t{++} reference type. @end deftypefn @deftypefn {Target Macro} void ADDRESS_TO_POINTER (struct type *@var{type}, char *@var{buf}, CORE_ADDR @var{addr}) @@ -1315,7 +1433,7 @@ Store in @var{buf} a pointer of type @var{type} representing the address @var{addr}, in the appropriate format for the current architecture. This function may safely assume that @var{type} is either a pointer or a -C++ reference type. +C@t{++} reference type. @end deftypefn @@ -1337,9 +1455,8 @@ raw representations are identical, and no special handling is needed. However, they do occasionally differ. For example: @itemize @bullet - @item -The x86 architecture supports an 80-bit long double type. However, when +The x86 architecture supports an 80-bit @code{long double} type. However, when we store those values in memory, they occupy twelve bytes: the floating-point number occupies the first ten, and the final two bytes are unused. This keeps the values aligned on four-byte boundaries, @@ -1353,17 +1470,16 @@ registers, with garbage in their upper bits. @value{GDBN} ignores the top 32 bits. Thus, the 64-bit form, with garbage in the upper 32 bits, is the raw representation, and the trimmed 32-bit representation is the virtual representation. - @end itemize In general, the raw representation is determined by the architecture, or @value{GDBN}'s interface to the architecture, while the virtual representation can be chosen for @value{GDBN}'s convenience. @value{GDBN}'s register file, -@code{registers}, holds the register contents in raw format, and the @value{GDBN} -remote protocol transmits register values in raw format. +@code{registers}, holds the register contents in raw format, and the +@value{GDBN} remote protocol transmits register values in raw format. -Your architecture may define the following macros to request raw / -virtual conversions: +Your architecture may define the following macros to request +conversions between the raw and virtual format: @deftypefn {Target Macro} int REGISTER_CONVERTIBLE (int @var{reg}) Return non-zero if register number @var{reg}'s value needs different raw @@ -1432,17 +1548,22 @@ machine. @table @code @item ADDITIONAL_OPTIONS -@item ADDITIONAL_OPTION_CASES -@item ADDITIONAL_OPTION_HANDLER -@item ADDITIONAL_OPTION_HELP +@itemx ADDITIONAL_OPTION_CASES +@itemx ADDITIONAL_OPTION_HANDLER +@itemx ADDITIONAL_OPTION_HELP +@findex ADDITIONAL_OPTION_HELP +@findex ADDITIONAL_OPTION_HANDLER +@findex ADDITIONAL_OPTION_CASES +@findex ADDITIONAL_OPTIONS These are a set of macros that allow the addition of additional command line options to @value{GDBN}. They are currently used only for the unsupported i960 Nindy target, and should not be used in any other configuration. @item ADDR_BITS_REMOVE (addr) +@findex ADDR_BITS_REMOVE If a raw machine instruction address includes any bits that are not really part of the address, then define this macro to expand into an -expression that zeros those bits in @var{addr}. This is only used for +expression that zeroes those bits in @var{addr}. This is only used for addresses of instructions, and even then not in all contexts. For example, the two low-order bits of the PC on the Hewlett-Packard PA @@ -1453,68 +1574,79 @@ address of the instruction. ADDR_BITS_REMOVE should filter out these bits with an expression such as @code{((addr) & ~3)}. @item ADDRESS_TO_POINTER (@var{type}, @var{buf}, @var{addr}) +@findex ADDRESS_TO_POINTER Store in @var{buf} a pointer of type @var{type} representing the address @var{addr}, in the appropriate format for the current architecture. This macro may safely assume that @var{type} is either a pointer or a -C++ reference type. +C@t{++} reference type. @xref{Target Architecture Definition, , Pointers Are Not Always Addresses}. @item BEFORE_MAIN_LOOP_HOOK +@findex BEFORE_MAIN_LOOP_HOOK Define this to expand into any code that you want to execute before the main loop starts. Although this is not, strictly speaking, a target conditional, that is how it is currently being used. Note that if a configuration were to define it one way for a host and a different way -for the target, @value{GDBN} will probably not compile, let alone run correctly. -This is currently used only for the unsupported i960 Nindy target, and -should not be used in any other configuration. +for the target, @value{GDBN} will probably not compile, let alone run +correctly. This macro is currently used only for the unsupported i960 Nindy +target, and should not be used in any other configuration. @item BELIEVE_PCC_PROMOTION -Define if the compiler promotes a short or char parameter to an int, but -still reports the parameter as its original type, rather than the -promoted type. +@findex BELIEVE_PCC_PROMOTION +Define if the compiler promotes a @code{short} or @code{char} +parameter to an @code{int}, but still reports the parameter as its +original type, rather than the promoted type. @item BELIEVE_PCC_PROMOTION_TYPE -Define this if @value{GDBN} should believe the type of a short argument when -compiled by pcc, but look within a full int space to get its value. -Only defined for Sun-3 at present. +@findex BELIEVE_PCC_PROMOTION_TYPE +Define this if @value{GDBN} should believe the type of a @code{short} +argument when compiled by @code{pcc}, but look within a full int space to get +its value. Only defined for Sun-3 at present. @item BITS_BIG_ENDIAN -Define this if the numbering of bits in the targets does *not* match the +@findex BITS_BIG_ENDIAN +Define this if the numbering of bits in the targets does @strong{not} match the endianness of the target byte order. A value of 1 means that the bits -are numbered in a big-endian order, 0 means little-endian. +are numbered in a big-endian bit order, 0 means little-endian. @item BREAKPOINT +@findex BREAKPOINT This is the character array initializer for the bit pattern to put into memory where a breakpoint is set. Although it's common to use a trap instruction for a breakpoint, it's not required; for instance, the bit pattern could be an invalid instruction. The breakpoint must be no longer than the shortest instruction of the architecture. -@var{BREAKPOINT} has been deprecated in favour of -@var{BREAKPOINT_FROM_PC}. +@code{BREAKPOINT} has been deprecated in favor of +@code{BREAKPOINT_FROM_PC}. @item BIG_BREAKPOINT -@item LITTLE_BREAKPOINT +@itemx LITTLE_BREAKPOINT +@findex LITTLE_BREAKPOINT +@findex BIG_BREAKPOINT Similar to BREAKPOINT, but used for bi-endian targets. -@var{BIG_BREAKPOINT} and @var{LITTLE_BREAKPOINT} have been deprecated in -favour of @var{BREAKPOINT_FROM_PC}. +@code{BIG_BREAKPOINT} and @code{LITTLE_BREAKPOINT} have been deprecated in +favor of @code{BREAKPOINT_FROM_PC}. @item REMOTE_BREAKPOINT -@item LITTLE_REMOTE_BREAKPOINT -@item BIG_REMOTE_BREAKPOINT +@itemx LITTLE_REMOTE_BREAKPOINT +@itemx BIG_REMOTE_BREAKPOINT +@findex BIG_REMOTE_BREAKPOINT +@findex LITTLE_REMOTE_BREAKPOINT +@findex REMOTE_BREAKPOINT Similar to BREAKPOINT, but used for remote targets. -@var{BIG_REMOTE_BREAKPOINT} and @var{LITTLE_REMOTE_BREAKPOINT} have been -deprecated in favour of @var{BREAKPOINT_FROM_PC}. - -@item BREAKPOINT_FROM_PC (pcptr, lenptr) +@code{BIG_REMOTE_BREAKPOINT} and @code{LITTLE_REMOTE_BREAKPOINT} have been +deprecated in favor of @code{BREAKPOINT_FROM_PC}. +@item BREAKPOINT_FROM_PC (@var{pcptr}, @var{lenptr}) +@findex BREAKPOINT_FROM_PC Use the program counter to determine the contents and size of a -breakpoint instruction. It returns a pointer to a string of bytes that -encode a breakpoint instruction, stores the length of the string to -*lenptr, and adjusts pc (if necessary) to point to the actual memory -location where the breakpoint should be inserted. +breakpoint instruction. It returns a pointer to a string of bytes +that encode a breakpoint instruction, stores the length of the string +to *@var{lenptr}, and adjusts pc (if necessary) to point to the actual +memory location where the breakpoint should be inserted. Although it is common to use a trap instruction for a breakpoint, it's not required; for instance, the bit pattern could be an invalid @@ -1523,79 +1655,94 @@ instruction of the architecture. Replaces all the other @var{BREAKPOINT} macros. -@item MEMORY_INSERT_BREAKPOINT (addr, contents_cache) -@item MEMORY_REMOVE_BREAKPOINT (addr, contents_cache) - +@item MEMORY_INSERT_BREAKPOINT (@var{addr}, @var{contents_cache}) +@itemx MEMORY_REMOVE_BREAKPOINT (@var{addr}, @var{contents_cache}) +@findex MEMORY_REMOVE_BREAKPOINT +@findex MEMORY_INSERT_BREAKPOINT Insert or remove memory based breakpoints. Reasonable defaults (@code{default_memory_insert_breakpoint} and @code{default_memory_remove_breakpoint} respectively) have been provided so that it is not necessary to define these for most architectures. Architectures which may want to define -@var{MEMORY_INSERT_BREAKPOINT} and @var{MEMORY_REMOVE_BREAKPOINT} will +@code{MEMORY_INSERT_BREAKPOINT} and @code{MEMORY_REMOVE_BREAKPOINT} will likely have instructions that are oddly sized or are not stored in a conventional manner. It may also be desirable (from an efficiency standpoint) to define custom breakpoint insertion and removal routines if -@var{BREAKPOINT_FROM_PC} needs to read the target's memory for some +@code{BREAKPOINT_FROM_PC} needs to read the target's memory for some reason. @item CALL_DUMMY_P +@findex CALL_DUMMY_P A C expresson that is non-zero when the target suports inferior function calls. @item CALL_DUMMY_WORDS -Pointer to an array of @var{LONGEST} words of data containing -host-byte-ordered @var{REGISTER_BYTES} sized values that partially +@findex CALL_DUMMY_WORDS +Pointer to an array of @code{LONGEST} words of data containing +host-byte-ordered @code{REGISTER_BYTES} sized values that partially specify the sequence of instructions needed for an inferior function call. -Should be deprecated in favour of a macro that uses target-byte-ordered +Should be deprecated in favor of a macro that uses target-byte-ordered data. @item SIZEOF_CALL_DUMMY_WORDS -The size of @var{CALL_DUMMY_WORDS}. When @var{CALL_DUMMY_P} this must -return a positive value. See also @var{CALL_DUMMY_LENGTH}. +@findex SIZEOF_CALL_DUMMY_WORDS +The size of @code{CALL_DUMMY_WORDS}. When @code{CALL_DUMMY_P} this must +return a positive value. See also @code{CALL_DUMMY_LENGTH}. @item CALL_DUMMY -A static initializer for @var{CALL_DUMMY_WORDS}. Deprecated. +@findex CALL_DUMMY +A static initializer for @code{CALL_DUMMY_WORDS}. Deprecated. @item CALL_DUMMY_LOCATION -inferior.h +@findex CALL_DUMMY_LOCATION +See the file @file{inferior.h}. @item CALL_DUMMY_STACK_ADJUST +@findex CALL_DUMMY_STACK_ADJUST Stack adjustment needed when performing an inferior function call. -Should be deprecated in favor of something like @var{STACK_ALIGN}. +Should be deprecated in favor of something like @code{STACK_ALIGN}. @item CALL_DUMMY_STACK_ADJUST_P -Predicate for use of @var{CALL_DUMMY_STACK_ADJUST}. +@findex CALL_DUMMY_STACK_ADJUST_P +Predicate for use of @code{CALL_DUMMY_STACK_ADJUST}. -Should be deprecated in favor of something like @var{STACK_ALIGN}. +Should be deprecated in favor of something like @code{STACK_ALIGN}. -@item CANNOT_FETCH_REGISTER (regno) +@item CANNOT_FETCH_REGISTER (@var{regno}) +@findex CANNOT_FETCH_REGISTER A C expression that should be nonzero if @var{regno} cannot be fetched from an inferior process. This is only relevant if @code{FETCH_INFERIOR_REGISTERS} is not defined. -@item CANNOT_STORE_REGISTER (regno) +@item CANNOT_STORE_REGISTER (@var{regno}) +@findex CANNOT_STORE_REGISTER A C expression that should be nonzero if @var{regno} should not be written to the target. This is often the case for program counters, -status words, and other special registers. If this is not defined, @value{GDBN} -will assume that all registers may be written. +status words, and other special registers. If this is not defined, +@value{GDBN} will assume that all registers may be written. @item DO_DEFERRED_STORES -@item CLEAR_DEFERRED_STORES +@itemx CLEAR_DEFERRED_STORES@item +@findex CLEAR_DEFERRED_STORES +@findex DO_DEFERRED_STORES Define this to execute any deferred stores of registers into the inferior, and to cancel any deferred stores. Currently only implemented correctly for native Sparc configurations? @item COERCE_FLOAT_TO_DOUBLE (@var{formal}, @var{actual}) +@findex COERCE_FLOAT_TO_DOUBLE +@cindex promotion to @code{double} If we are calling a function by hand, and the function was declared (according to the debug info) without a prototype, should we -automatically promote floats to doubles? This macro must evaluate to -non-zero if we should, or zero if we should leave the value alone. +automatically promote @code{float}s to @code{double}s? This macro +must evaluate to non-zero if we should, or zero if we should leave the +value alone. The argument @var{actual} is the type of the value we want to pass to the function. The argument @var{formal} is the type of this argument, @@ -1605,138 +1752,172 @@ we're passing more arguments than are officially declared (for example, varargs). This macro is never invoked if the function definitely has a prototype. +@findex set_gdbarch_coerce_float_to_double +@findex standard_coerce_float_to_double The default behavior is to promote only when we have no type information for the formal parameter. This is different from the obvious behavior, which would be to promote whenever we have no prototype, just as the compiler does. It's annoying, but some older targets rely on this. If -you want @value{GDBN} to follow the typical compiler behavior --- to always -promote when there is no prototype in scope --- your gdbarch init +you want @value{GDBN} to follow the typical compiler behavior---to always +promote when there is no prototype in scope---your gdbarch @code{init} function can call @code{set_gdbarch_coerce_float_to_double} and select the @code{standard_coerce_float_to_double} function. @item CPLUS_MARKER -Define this to expand into the character that G++ uses to distinguish +@findex CPLUS_MARKERz +Define this to expand into the character that G@t{++} uses to distinguish compiler-generated identifiers from programmer-specified identifiers. By default, this expands into @code{'$'}. Most System V targets should define this to @code{'.'}. @item DBX_PARM_SYMBOL_CLASS +@findex DBX_PARM_SYMBOL_CLASS Hook for the @code{SYMBOL_CLASS} of a parameter when decoding DBX symbol information. In the i960, parameters can be stored as locals or as args, depending on the type of the debug record. @item DECR_PC_AFTER_BREAK +@findex DECR_PC_AFTER_BREAK Define this to be the amount by which to decrement the PC after the program encounters a breakpoint. This is often the number of bytes in -BREAKPOINT, though not always. For most targets this value will be 0. +@code{BREAKPOINT}, though not always. For most targets this value will be 0. @item DECR_PC_AFTER_HW_BREAK +@findex DECR_PC_AFTER_HW_BREAK Similarly, for hardware breakpoints. -@item DISABLE_UNSETTABLE_BREAK addr +@item DISABLE_UNSETTABLE_BREAK (@var{addr}) +@findex DISABLE_UNSETTABLE_BREAK If defined, this should evaluate to 1 if @var{addr} is in a shared library in which breakpoints cannot be set and so should be disabled. @item DO_REGISTERS_INFO +@findex DO_REGISTERS_INFO If defined, use this to print the value of a register or all registers. @item DWARF_REG_TO_REGNUM +@findex DWARF_REG_TO_REGNUM Convert DWARF register number into @value{GDBN} regnum. If not defined, no conversion will be performed. @item DWARF2_REG_TO_REGNUM +@findex DWARF2_REG_TO_REGNUM Convert DWARF2 register number into @value{GDBN} regnum. If not defined, no conversion will be performed. @item ECOFF_REG_TO_REGNUM +@findex ECOFF_REG_TO_REGNUM Convert ECOFF register number into @value{GDBN} regnum. If not defined, no conversion will be performed. @item END_OF_TEXT_DEFAULT -This is an expression that should designate the end of the text section -(? FIXME ?) +@findex END_OF_TEXT_DEFAULT +This is an expression that should designate the end of the text section. +@c (? FIXME ?) -@item EXTRACT_RETURN_VALUE(type,regbuf,valbuf) +@item EXTRACT_RETURN_VALUE(@var{type}, @var{regbuf}, @var{valbuf}) +@findex EXTRACT_RETURN_VALUE Define this to extract a function's return value of type @var{type} from the raw register state @var{regbuf} and copy that, in virtual format, into @var{valbuf}. -@item EXTRACT_STRUCT_VALUE_ADDRESS(regbuf) -When @var{EXTRACT_STRUCT_VALUE_ADDRESS_P} this is used to to extract +@item EXTRACT_STRUCT_VALUE_ADDRESS(@var{regbuf}) +@findex EXTRACT_STRUCT_VALUE_ADDRESS +When @code{EXTRACT_STRUCT_VALUE_ADDRESS_P} is non-zero, this is used to extract from an array @var{regbuf} (containing the raw register state) the address in which a function should return its structure value, as a -CORE_ADDR (or an expression that can be used as one). +@code{CORE_ADDR} (or an expression that can be used as one). @item EXTRACT_STRUCT_VALUE_ADDRESS_P -Predicate for @var{EXTRACT_STRUCT_VALUE_ADDRESS}. +@findex EXTRACT_STRUCT_VALUE_ADDRESS_P +Predicate for @code{EXTRACT_STRUCT_VALUE_ADDRESS}. @item FLOAT_INFO -If defined, then the `info float' command will print information about +@findex FLOAT_INFO +If defined, then the @samp{info float} command will print information about the processor's floating point unit. @item FP_REGNUM +@findex FP_REGNUM If the virtual frame pointer is kept in a register, then define this macro to be the number (greater than or equal to zero) of that register. This should only need to be defined if @code{TARGET_READ_FP} and @code{TARGET_WRITE_FP} are not defined. -@item FRAMELESS_FUNCTION_INVOCATION(fi) +@item FRAMELESS_FUNCTION_INVOCATION(@var{fi}) +@findex FRAMELESS_FUNCTION_INVOCATION Define this to an expression that returns 1 if the function invocation represented by @var{fi} does not have a stack frame associated with it. Otherwise return 0. -@item FRAME_ARGS_ADDRESS_CORRECT -stack.c +@item FRAME_ARGS_ADDRESS_CORRECT@item +@findex FRAME_ARGS_ADDRESS_CORRECT +See @file{stack.c}. -@item FRAME_CHAIN(frame) +@item FRAME_CHAIN(@var{frame}) +@findex FRAME_CHAIN Given @var{frame}, return a pointer to the calling frame. -@item FRAME_CHAIN_COMBINE(chain,frame) +@item FRAME_CHAIN_COMBINE(@var{chain}, @var{frame}) +@findex FRAME_CHAIN_COMBINE Define this to take the frame chain pointer and the frame's nominal address and produce the nominal address of the caller's frame. Presently only defined for HP PA. -@item FRAME_CHAIN_VALID(chain,thisframe) - +@item FRAME_CHAIN_VALID(@var{chain}, @var{thisframe}) +@findex FRAME_CHAIN_VALID Define this to be an expression that returns zero if the given frame is an outermost frame, with no caller, and nonzero otherwise. Several -common definitions are available. +common definitions are available: +@itemize @bullet +@item @code{file_frame_chain_valid} is nonzero if the chain pointer is nonzero and given frame's PC is not inside the startup file (such as -@file{crt0.o}). @code{func_frame_chain_valid} is nonzero if the chain -pointer is nonzero and the given frame's PC is not in @code{main()} or a -known entry point function (such as @code{_start()}). +@file{crt0.o}). + +@item +@code{func_frame_chain_valid} is nonzero if the chain +pointer is nonzero and the given frame's PC is not in @code{main} or a +known entry point function (such as @code{_start}). + +@item @code{generic_file_frame_chain_valid} and @code{generic_func_frame_chain_valid} are equivalent implementations for targets using generic dummy frames. +@end itemize -@item FRAME_INIT_SAVED_REGS(frame) +@item FRAME_INIT_SAVED_REGS(@var{frame}) +@findex FRAME_INIT_SAVED_REGS See @file{frame.h}. Determines the address of all registers in the current stack frame storing each in @code{frame->saved_regs}. Space for @code{frame->saved_regs} shall be allocated by @code{FRAME_INIT_SAVED_REGS} using either @code{frame_saved_regs_zalloc} or @code{frame_obstack_alloc}. -@var{FRAME_FIND_SAVED_REGS} and @var{EXTRA_FRAME_INFO} are deprecated. +@code{FRAME_FIND_SAVED_REGS} and @code{EXTRA_FRAME_INFO} are deprecated. -@item FRAME_NUM_ARGS (fi) +@item FRAME_NUM_ARGS (@var{fi}) +@findex FRAME_NUM_ARGS For the frame described by @var{fi} return the number of arguments that are being passed. If the number of arguments is not known, return @code{-1}. -@item FRAME_SAVED_PC(frame) -Given @var{frame}, return the pc saved there. That is, the return +@item FRAME_SAVED_PC(@var{frame}) +@findex FRAME_SAVED_PC +Given @var{frame}, return the pc saved there. This is the return address. @item FUNCTION_EPILOGUE_SIZE +@findex FUNCTION_EPILOGUE_SIZE For some COFF targets, the @code{x_sym.x_misc.x_fsize} field of the function end symbol is 0. For such targets, you must define @code{FUNCTION_EPILOGUE_SIZE} to expand into the standard size of a function's epilogue. @item FUNCTION_START_OFFSET +@findex FUNCTION_START_OFFSET An integer, giving the offset in bytes from a function's address (as used in the values of symbols, function pointers, etc.), and the function's first genuine instruction. @@ -1751,54 +1932,66 @@ its first instruction is two bytes, @code{FUNCTION_START_OFFSET} would be 2 on the VAX. @item GCC_COMPILED_FLAG_SYMBOL -@item GCC2_COMPILED_FLAG_SYMBOL -If defined, these are the names of the symbols that @value{GDBN} will look for to -detect that GCC compiled the file. The default symbols are -@code{gcc_compiled.} and @code{gcc2_compiled.}, respectively. (Currently -only defined for the Delta 68.) +@itemx GCC2_COMPILED_FLAG_SYMBOL +@findex GCC2_COMPILED_FLAG_SYMBOL +@findex GCC_COMPILED_FLAG_SYMBOL +If defined, these are the names of the symbols that @value{GDBN} will +look for to detect that GCC compiled the file. The default symbols +are @code{gcc_compiled.} and @code{gcc2_compiled.}, +respectively. (Currently only defined for the Delta 68.) @item @value{GDBN}_MULTI_ARCH +@findex @value{GDBN}_MULTI_ARCH If defined and non-zero, enables suport for multiple architectures within @value{GDBN}. -The support can be enabled at two levels. At level one, only +This support can be enabled at two levels. At level one, only definitions for previously undefined macros are provided; at level two, a multi-arch definition of all architecture dependant macros will be defined. @item @value{GDBN}_TARGET_IS_HPPA -This determines whether horrible kludge code in dbxread.c and -partial-stab.h is used to mangle multiple-symbol-table files from -HPPA's. This should all be ripped out, and a scheme like elfread.c -used. +@findex @value{GDBN}_TARGET_IS_HPPA +This determines whether horrible kludge code in @file{dbxread.c} and +@file{partial-stab.h} is used to mangle multiple-symbol-table files from +HPPA's. This should all be ripped out, and a scheme like @file{elfread.c} +used instead. @item GET_LONGJMP_TARGET +@findex GET_LONGJMP_TARGET For most machines, this is a target-dependent parameter. On the DECstation and the Iris, this is a native-dependent parameter, since -<setjmp.h> is needed to define it. +trhe header file @file{setjmp.h} is needed to define it. -This macro determines the target PC address that longjmp() will jump to, -assuming that we have just stopped at a longjmp breakpoint. It takes a -CORE_ADDR * as argument, and stores the target PC value through this +This macro determines the target PC address that @code{longjmp} will jump to, +assuming that we have just stopped at a @code{longjmp} breakpoint. It takes a +@code{CORE_ADDR *} as argument, and stores the target PC value through this pointer. It examines the current state of the machine as needed. @item GET_SAVED_REGISTER +@findex GET_SAVED_REGISTER +@findex get_saved_register Define this if you need to supply your own definition for the function @code{get_saved_register}. @item HAVE_REGISTER_WINDOWS +@findex HAVE_REGISTER_WINDOWS Define this if the target has register windows. -@item REGISTER_IN_WINDOW_P (regnum) + +@item REGISTER_IN_WINDOW_P (@var{regnum}) +@findex REGISTER_IN_WINDOW_P Define this to be an expression that is 1 if the given register is in the window. @item IBM6000_TARGET +@findex IBM6000_TARGET Shows that we are configured for an IBM RS/6000 target. This conditional should be eliminated (FIXME) and replaced by -feature-specific macros. It was introduced in haste and we are +feature-specific macros. It was introduced in a haste and we are repenting at leisure. @item SYMBOLS_CAN_START_WITH_DOLLAR +@findex SYMBOLS_CAN_START_WITH_DOLLAR Some systems have routines whose names start with @samp{$}. Giving this macro a non-zero value tells @value{GDBN}'s expression parser to check for such routines when parsing tokens that begin with @samp{$}. @@ -1808,94 +2001,115 @@ On HP-UX, certain system routines (millicode) have names beginning with routine that handles inter-space procedure calls on PA-RISC. @item IEEE_FLOAT +@findex IEEE_FLOAT Define this if the target system uses IEEE-format floating point numbers. -@item INIT_EXTRA_FRAME_INFO (fromleaf, frame) +@item INIT_EXTRA_FRAME_INFO (@var{fromleaf}, @var{frame}) +@findex INIT_EXTRA_FRAME_INFO If additional information about the frame is required this should be stored in @code{frame->extra_info}. Space for @code{frame->extra_info} is allocated using @code{frame_obstack_alloc}. -@item INIT_FRAME_PC (fromleaf, prev) +@item INIT_FRAME_PC (@var{fromleaf}, @var{prev}) +@findex INIT_FRAME_PC This is a C statement that sets the pc of the frame pointed to by @var{prev}. [By default...] -@item INNER_THAN (lhs,rhs) +@item INNER_THAN (@var{lhs}, @var{rhs}) +@findex INNER_THAN Returns non-zero if stack address @var{lhs} is inner than (nearer to the stack top) stack address @var{rhs}. Define this as @code{lhs < rhs} if the target's stack grows downward in memory, or @code{lhs > rsh} if the stack grows upward. -@item IN_SIGTRAMP (pc, name) -Define this to return true if the given @var{pc} and/or @var{name} -indicates that the current function is a sigtramp. +@item IN_SIGTRAMP (@var{pc}, @var{name}) +@findex IN_SIGTRAMP +Define this to return non-zero if the given @var{pc} and/or @var{name} +indicates that the current function is a @code{sigtramp}. -@item SIGTRAMP_START (pc) -@item SIGTRAMP_END (pc) -Define these to be the start and end address of the sigtramp for the +@item SIGTRAMP_START (@var{pc}) +@findex SIGTRAMP_START +@itemx SIGTRAMP_END (@var{pc}) +@findex SIGTRAMP_END +Define these to be the start and end address of the @code{sigtramp} for the given @var{pc}. On machines where the address is just a compile time constant, the macro expansion will typically just ignore the supplied @var{pc}. -@item IN_SOLIB_CALL_TRAMPOLINE pc name +@item IN_SOLIB_CALL_TRAMPOLINE (@var{pc}, @var{name}) +@findex IN_SOLIB_CALL_TRAMPOLINE Define this to evaluate to nonzero if the program is stopped in the trampoline that connects to a shared library. -@item IN_SOLIB_RETURN_TRAMPOLINE pc name +@item IN_SOLIB_RETURN_TRAMPOLINE (@var{pc}, @var{name}) +@findex IN_SOLIB_RETURN_TRAMPOLINE Define this to evaluate to nonzero if the program is stopped in the trampoline that returns from a shared library. -@item IN_SOLIB_DYNSYM_RESOLVE_CODE pc +@item IN_SOLIB_DYNSYM_RESOLVE_CODE (@var{pc}) +@findex IN_SOLIB_DYNSYM_RESOLVE_CODE Define this to evaluate to nonzero if the program is stopped in the dynamic linker. -@item SKIP_SOLIB_RESOLVER pc +@item SKIP_SOLIB_RESOLVER (@var{pc}) +@findex SKIP_SOLIB_RESOLVER Define this to evaluate to the (nonzero) address at which execution should continue to get past the dynamic linker's symbol resolution function. A zero value indicates that it is not important or necessary to set a breakpoint to get through the dynamic linker and that single stepping will suffice. -@item IS_TRAPPED_INTERNALVAR (name) +@item IS_TRAPPED_INTERNALVAR (@var{name}) +@findex IS_TRAPPED_INTERNALVAR This is an ugly hook to allow the specification of special actions that should occur as a side-effect of setting the value of a variable internal to @value{GDBN}. Currently only used by the h8500. Note that this could be either a host or target conditional. @item NEED_TEXT_START_END +@findex NEED_TEXT_START_END Define this if @value{GDBN} should determine the start and end addresses of the text section. (Seems dubious.) @item NO_HIF_SUPPORT +@findex NO_HIF_SUPPORT (Specific to the a29k.) @item POINTER_TO_ADDRESS (@var{type}, @var{buf}) +@findex POINTER_TO_ADDRESS Assume that @var{buf} holds a pointer of type @var{type}, in the appropriate format for the current architecture. Return the byte address the pointer refers to. @xref{Target Architecture Definition, , Pointers Are Not Always Addresses}. @item REGISTER_CONVERTIBLE (@var{reg}) +@findex REGISTER_CONVERTIBLE Return non-zero if @var{reg} uses different raw and virtual formats. @xref{Target Architecture Definition, , Using Different Register and Memory Data Representations}. @item REGISTER_RAW_SIZE (@var{reg}) +@findex REGISTER_RAW_SIZE Return the raw size of @var{reg}. @xref{Target Architecture Definition, , Using Different Register and Memory Data Representations}. @item REGISTER_VIRTUAL_SIZE (@var{reg}) +@findex REGISTER_VIRTUAL_SIZE Return the virtual size of @var{reg}. @xref{Target Architecture Definition, , Using Different Register and Memory Data Representations}. @item REGISTER_VIRTUAL_TYPE (@var{reg}) +@findex REGISTER_VIRTUAL_TYPE Return the virtual type of @var{reg}. @xref{Target Architecture Definition, , Using Different Register and Memory Data Representations}. @item REGISTER_CONVERT_TO_VIRTUAL(@var{reg}, @var{type}, @var{from}, @var{to}) +@findex REGISTER_CONVERT_TO_VIRTUAL Convert the value of register @var{reg} from its raw form to its virtual form. @xref{Target Architecture Definition, , Using Different Register and Memory Data Representations}. @item REGISTER_CONVERT_TO_RAW(@var{type}, @var{reg}, @var{from}, @var{to}) +@findex REGISTER_CONVERT_TO_RAW Convert the value of register @var{reg} from its virtual form to its raw form. @xref{Target Architecture Definition, , Using Different Register and Memory Data Representations}. @@ -1913,8 +2127,8 @@ and whether an inferior function call reserves space on the stack for the return value. The full logic @value{GDBN} uses here is kind of odd. -@itemize @bullet +@itemize @bullet @item If the type being returned by value is not a structure, union, or array, and @code{RETURN_VALUE_ON_STACK} returns zero, then @value{GDBN} @@ -1924,7 +2138,6 @@ concludes the value is not returned using the struct convention. Otherwise, @value{GDBN} calls @code{USE_STRUCT_CONVENTION} (see below). If that returns non-zero, @value{GDBN} assumes the struct convention is in use. - @end itemize In other words, to indicate that a given type is returned by value using @@ -1932,23 +2145,25 @@ the struct convention, that type must be either a struct, union, array, or something @code{RETURN_VALUE_ON_STACK} likes, @emph{and} something that @code{USE_STRUCT_CONVENTION} likes. -Note that, in C and C++, arrays are never returned by value. In those +Note that, in C and C@t{++}, arrays are never returned by value. In those languages, these predicates will always see a pointer type, never an array type. All the references above to arrays being returned by value apply only to other languages. @item SOFTWARE_SINGLE_STEP_P +@findex SOFTWARE_SINGLE_STEP_P Define this as 1 if the target does not have a hardware single-step -mechanism. The macro @code{SOFTWARE_SINGLE_STEP} must also be defined. +mechanism. The macro @code{SOFTWARE_SINGLE_STEP} must also be defined. -@item SOFTWARE_SINGLE_STEP(signal,insert_breapoints_p) -A function that inserts or removes (dependant on +@item SOFTWARE_SINGLE_STEP(@var{signal}, @var{insert_breapoints_p}) +@findex SOFTWARE_SINGLE_STEP +A function that inserts or removes (depending on @var{insert_breapoints_p}) breakpoints at each possible destinations of -the next instruction. See @code{sparc-tdep.c} and @code{rs6000-tdep.c} +the next instruction. See @file{sparc-tdep.c} and @file{rs6000-tdep.c} for examples. @item SOFUN_ADDRESS_MAYBE_MISSING - +@findex SOFUN_ADDRESS_MAYBE_MISSING Somebody clever observed that, the more actual addresses you have in the debug information, the more time the linker has to spend relocating them. So whenever there's some other way the debugger could find the @@ -1962,14 +2177,14 @@ the beginning and ending addresses of compilation units in the text segment. @code{N_FUN} stabs mark the starts and ends of functions. @code{SOFUN_ADDRESS_MAYBE_MISSING} means two things: -@itemize @bullet +@itemize @bullet @item @code{N_FUN} stabs have an address of zero. Instead, you should find the addresses where the function starts by taking the function name from -the stab, and then looking that up in the minsyms (the linker/ -assembler symbol table). In other words, the stab has the name, and -the linker / assembler symbol table is the only place that carries +the stab, and then looking that up in the minsyms (the +linker/assembler symbol table). In other words, the stab has the +name, and the linker/assembler symbol table is the only place that carries the address. @item @@ -1977,20 +2192,23 @@ the address. @code{N_FUN} stabs that appear before and after the @code{N_SO} stab, and guess the starting and ending addresses of the compilation unit from them. - @end itemize @item PCC_SOL_BROKEN +@findex PCC_SOL_BROKEN (Used only in the Convex target.) @item PC_IN_CALL_DUMMY -inferior.h +@findex PC_IN_CALL_DUMMY +See @file{inferior.h}. @item PC_LOAD_SEGMENT +@findex PC_LOAD_SEGMENT If defined, print information about the load segment for the program counter. (Defined only for the RS/6000.) @item PC_REGNUM +@findex PC_REGNUM If the program counter is kept in a register, then define this macro to be the number (greater than or equal to zero) of that register. @@ -1998,98 +2216,123 @@ This should only need to be defined if @code{TARGET_READ_PC} and @code{TARGET_WRITE_PC} are not defined. @item NPC_REGNUM +@findex NPC_REGNUM The number of the ``next program counter'' register, if defined. @item NNPC_REGNUM +@findex NNPC_REGNUM The number of the ``next next program counter'' register, if defined. Currently, this is only defined for the Motorola 88K. @item PARM_BOUNDARY +@findex PARM_BOUNDARY If non-zero, round arguments to a boundary of this many bits before pushing them on the stack. -@item PRINT_REGISTER_HOOK (regno) +@item PRINT_REGISTER_HOOK (@var{regno}) +@findex PRINT_REGISTER_HOOK If defined, this must be a function that prints the contents of the given register to standard output. @item PRINT_TYPELESS_INTEGER +@findex PRINT_TYPELESS_INTEGER This is an obscure substitute for @code{print_longest} that seems to have been defined for the Convex target. @item PROCESS_LINENUMBER_HOOK +@findex PROCESS_LINENUMBER_HOOK A hook defined for XCOFF reading. @item PROLOGUE_FIRSTLINE_OVERLAP +@findex PROLOGUE_FIRSTLINE_OVERLAP (Only used in unsupported Convex configuration.) @item PS_REGNUM +@findex PS_REGNUM If defined, this is the number of the processor status register. (This definition is only used in generic code when parsing "$ps".) @item POP_FRAME +@findex POP_FRAME +@findex call_function_by_hand +@findex return_command Used in @samp{call_function_by_hand} to remove an artificial stack frame and in @samp{return_command} to remove a real stack frame. -@item PUSH_ARGUMENTS (nargs, args, sp, struct_return, struct_addr) +@item PUSH_ARGUMENTS (@var{nargs}, @var{args}, @var{sp}, @var{struct_return}, @var{struct_addr}) +@findex PUSH_ARGUMENTS Define this to push arguments onto the stack for inferior function -call. Return the updated stack pointer value. +call. Returns the updated stack pointer value. @item PUSH_DUMMY_FRAME +@findex PUSH_DUMMY_FRAME Used in @samp{call_function_by_hand} to create an artificial stack frame. @item REGISTER_BYTES +@findex REGISTER_BYTES The total amount of space needed to store @value{GDBN}'s copy of the machine's register state. -@item REGISTER_NAME(i) -Return the name of register @var{i} as a string. May return @var{NULL} -or @var{NUL} to indicate that register @var{i} is not valid. +@item REGISTER_NAME(@var{i}) +@findex REGISTER_NAME +Return the name of register @var{i} as a string. May return @code{NULL} +or @code{NUL} to indicate that register @var{i} is not valid. @item REGISTER_NAMES -Deprecated in favor of @var{REGISTER_NAME}. +@findex REGISTER_NAMES +Deprecated in favor of @code{REGISTER_NAME}. -@item REG_STRUCT_HAS_ADDR (gcc_p, type) +@item REG_STRUCT_HAS_ADDR (@var{gcc_p}, @var{type}) +@findex REG_STRUCT_HAS_ADDR Define this to return 1 if the given type will be passed by pointer rather than directly. -@item SAVE_DUMMY_FRAME_TOS (sp) +@item SAVE_DUMMY_FRAME_TOS (@var{sp}) +@findex SAVE_DUMMY_FRAME_TOS Used in @samp{call_function_by_hand} to notify the target dependent code of the top-of-stack value that will be passed to the the inferior code. -This is the value of the @var{SP} after both the dummy frame and space +This is the value of the @code{SP} after both the dummy frame and space for parameters/results have been allocated on the stack. @item SDB_REG_TO_REGNUM +@findex SDB_REG_TO_REGNUM Define this to convert sdb register numbers into @value{GDBN} regnums. If not defined, no conversion will be done. @item SHIFT_INST_REGS +@findex SHIFT_INST_REGS (Only used for m88k targets.) @item SKIP_PERMANENT_BREAKPOINT +@findex SKIP_PERMANENT_BREAKPOINT Advance the inferior's PC past a permanent breakpoint. @value{GDBN} normally steps over a breakpoint by removing it, stepping one instruction, and re-inserting the breakpoint. However, permanent breakpoints are hardwired into the inferior, and can't be removed, so this strategy -doesn't work. Calling SKIP_PERMANENT_BREAKPOINT adjusts the processor's +doesn't work. Calling @code{SKIP_PERMANENT_BREAKPOINT} adjusts the processor's state so that execution will resume just after the breakpoint. This macro does the right thing even when the breakpoint is in the delay slot of a branch or jump. -@item SKIP_PROLOGUE (pc) +@item SKIP_PROLOGUE (@var{pc}) +@findex SKIP_PROLOGUE A C expression that returns the address of the ``real'' code beyond the function entry prologue found at @var{pc}. @item SKIP_PROLOGUE_FRAMELESS_P +@findex SKIP_PROLOGUE_FRAMELESS_P A C expression that should behave similarly, but that can stop as soon as the function is known to have a frame. If not defined, @code{SKIP_PROLOGUE} will be used instead. -@item SKIP_TRAMPOLINE_CODE (pc) +@item SKIP_TRAMPOLINE_CODE (@var{pc}) +@findex SKIP_TRAMPOLINE_CODE If the target machine has trampoline code that sits between callers and the functions being called, then define this macro to return a new PC that is at the start of the real function. @item SP_REGNUM +@findex SP_REGNUM If the stack-pointer is kept in a register, then define this macro to be the number (greater than or equal to zero) of that register. @@ -2097,85 +2340,116 @@ This should only need to be defined if @code{TARGET_WRITE_SP} and @code{TARGET_WRITE_SP} are not defined. @item STAB_REG_TO_REGNUM +@findex STAB_REG_TO_REGNUM Define this to convert stab register numbers (as gotten from `r' declarations) into @value{GDBN} regnums. If not defined, no conversion will be done. -@item STACK_ALIGN (addr) +@item STACK_ALIGN (@var{addr}) +@findex STACK_ALIGN Define this to adjust the address to the alignment required for the processor's stack. -@item STEP_SKIPS_DELAY (addr) +@item STEP_SKIPS_DELAY (@var{addr}) +@findex STEP_SKIPS_DELAY Define this to return true if the address is of an instruction with a delay slot. If a breakpoint has been placed in the instruction's delay slot, @value{GDBN} will single-step over that instruction before resuming normally. Currently only defined for the Mips. -@item STORE_RETURN_VALUE (type, valbuf) +@item STORE_RETURN_VALUE (@var{type}, @var{valbuf}) +@findex STORE_RETURN_VALUE A C expression that stores a function return value of type @var{type}, where @var{valbuf} is the address of the value to be stored. @item SUN_FIXED_LBRAC_BUG +@findex SUN_FIXED_LBRAC_BUG (Used only for Sun-3 and Sun-4 targets.) @item SYMBOL_RELOADING_DEFAULT -The default value of the `symbol-reloading' variable. (Never defined in +@findex SYMBOL_RELOADING_DEFAULT +The default value of the ``symbol-reloading'' variable. (Never defined in current sources.) @item TARGET_BYTE_ORDER_DEFAULT +@findex TARGET_BYTE_ORDER_DEFAULT The ordering of bytes in the target. This must be either @code{BIG_ENDIAN} or @code{LITTLE_ENDIAN}. This macro replaces -@var{TARGET_BYTE_ORDER} which is deprecated. +@code{TARGET_BYTE_ORDER} which is deprecated. @item TARGET_BYTE_ORDER_SELECTABLE_P +@findex TARGET_BYTE_ORDER_SELECTABLE_P Non-zero if the target has both @code{BIG_ENDIAN} and @code{LITTLE_ENDIAN} variants. This macro replaces -@var{TARGET_BYTE_ORDER_SELECTABLE} which is deprecated. +@code{TARGET_BYTE_ORDER_SELECTABLE} which is deprecated. @item TARGET_CHAR_BIT +@findex TARGET_CHAR_BIT Number of bits in a char; defaults to 8. @item TARGET_COMPLEX_BIT +@findex TARGET_COMPLEX_BIT Number of bits in a complex number; defaults to @code{2 * TARGET_FLOAT_BIT}. At present this macro is not used. @item TARGET_DOUBLE_BIT +@findex TARGET_DOUBLE_BIT Number of bits in a double float; defaults to @code{8 * TARGET_CHAR_BIT}. @item TARGET_DOUBLE_COMPLEX_BIT +@findex TARGET_DOUBLE_COMPLEX_BIT Number of bits in a double complex; defaults to @code{2 * TARGET_DOUBLE_BIT}. At present this macro is not used. @item TARGET_FLOAT_BIT +@findex TARGET_FLOAT_BIT Number of bits in a float; defaults to @code{4 * TARGET_CHAR_BIT}. @item TARGET_INT_BIT +@findex TARGET_INT_BIT Number of bits in an integer; defaults to @code{4 * TARGET_CHAR_BIT}. @item TARGET_LONG_BIT +@findex TARGET_LONG_BIT Number of bits in a long integer; defaults to @code{4 * TARGET_CHAR_BIT}. @item TARGET_LONG_DOUBLE_BIT +@findex TARGET_LONG_DOUBLE_BIT Number of bits in a long double float; defaults to @code{2 * TARGET_DOUBLE_BIT}. @item TARGET_LONG_LONG_BIT +@findex TARGET_LONG_LONG_BIT Number of bits in a long long integer; defaults to @code{2 * TARGET_LONG_BIT}. @item TARGET_PTR_BIT +@findex TARGET_PTR_BIT Number of bits in a pointer; defaults to @code{TARGET_INT_BIT}. @item TARGET_SHORT_BIT +@findex TARGET_SHORT_BIT Number of bits in a short integer; defaults to @code{2 * TARGET_CHAR_BIT}. @item TARGET_READ_PC -@item TARGET_WRITE_PC (val, pid) -@item TARGET_READ_SP -@item TARGET_WRITE_SP -@item TARGET_READ_FP -@item TARGET_WRITE_FP +@findex TARGET_READ_PC +@itemx TARGET_WRITE_PC (@var{val}, @var{pid}) +@findex TARGET_WRITE_PC +@itemx TARGET_READ_SP +@findex TARGET_READ_SP +@itemx TARGET_WRITE_SP +@findex TARGET_WRITE_SP +@itemx TARGET_READ_FP +@findex TARGET_READ_FP +@itemx TARGET_WRITE_FP +@findex TARGET_WRITE_FP +@findex read_pc +@findex write_pc +@findex read_sp +@findex write_sp +@findex read_fp +@findex write_fp These change the behavior of @code{read_pc}, @code{write_pc}, @code{read_sp}, @code{write_sp}, @code{read_fp} and @code{write_fp}. For most targets, these may be left undefined. @value{GDBN} will call the read @@ -2185,13 +2459,15 @@ These macros are useful when a target keeps one of these registers in a hard to get at place; for example, part in a segment register and part in an ordinary register. -@item TARGET_VIRTUAL_FRAME_POINTER(pc,regp,offsetp) +@item TARGET_VIRTUAL_FRAME_POINTER(@var{pc}, @var{regp}, @var{offsetp}) +@findex TARGET_VIRTUAL_FRAME_POINTER Returns a @code{(register, offset)} pair representing the virtual -frame pointer in use at the code address @code{"pc"}. If virtual +frame pointer in use at the code address @var{pc}. If virtual frame pointers are not used, a default definition simply returns @code{FP_REGNUM}, with an offset of zero. -@item USE_STRUCT_CONVENTION (gcc_p, type) +@item USE_STRUCT_CONVENTION (@var{gcc_p}, @var{type}) +@findex USE_STRUCT_CONVENTION If defined, this must be an expression that is nonzero if a value of the given @var{type} being returned from a function must have space allocated for it on the stack. @var{gcc_p} is true if the function @@ -2199,7 +2475,8 @@ being considered is known to have been compiled by GCC; this is helpful for systems where GCC is known to use different calling convention than other compilers. -@item VARIABLES_INSIDE_BLOCK (desc, gcc_p) +@item VARIABLES_INSIDE_BLOCK (@var{desc}, @var{gcc_p}) +@findex VARIABLES_INSIDE_BLOCK For dbx-style debugging information, if the compiler puts variable declarations inside LBRAC/RBRAC blocks, this should be defined to be nonzero. @var{desc} is the value of @code{n_desc} from the @@ -2207,30 +2484,29 @@ nonzero. @var{desc} is the value of @code{n_desc} from the presence of either the @code{GCC_COMPILED_SYMBOL} or the @code{GCC2_COMPILED_SYMBOL}. By default, this is 0. -@item OS9K_VARIABLES_INSIDE_BLOCK (desc, gcc_p) +@item OS9K_VARIABLES_INSIDE_BLOCK (@var{desc}, @var{gcc_p}) +@findex OS9K_VARIABLES_INSIDE_BLOCK Similarly, for OS/9000. Defaults to 1. - @end table Motorola M68K target conditionals. -@table @code - +@ftable @code @item BPT_VECTOR Define this to be the 4-bit location of the breakpoint trap vector. If not defined, it will default to @code{0xf}. @item REMOTE_BPT_VECTOR Defaults to @code{1}. - -@end table +@end ftable @section Adding a New Target +@cindex adding a target The following files define a target to @value{GDBN}: @table @file - +@vindex TDEPFILES @item gdb/config/@var{arch}/@var{ttt}.mt Contains a Makefile fragment specific to this target. Specifies what object files are needed for target @var{ttt}, by defining @@ -2243,7 +2519,7 @@ but these are now deprecated, replaced by autoconf, and may go away in future versions of @value{GDBN}. @item gdb/config/@var{arch}/tm-@var{ttt}.h -(@file{tm.h} is a link to this file, created by configure). Contains +(@file{tm.h} is a link to this file, created by @code{configure}). Contains macro definitions about the target machine's registers, stack frame format and instructions. @@ -2257,20 +2533,19 @@ and debug. @item gdb/config/@var{arch}/tm-@var{arch}.h This often exists to describe the basic layout of the target machine's -processor chip (registers, stack, etc). If used, it is included by +processor chip (registers, stack, etc.). If used, it is included by @file{tm-@var{ttt}.h}. It can be shared among many targets that use the same processor. @item gdb/@var{arch}-tdep.c Similarly, there are often common subroutines that are shared by all target machines that use this particular architecture. - @end table If you are adding a new operating system for an existing CPU chip, add a @file{config/tm-@var{os}.h} file that describes the operating system facilities that are unusual (extra symbol table info; the breakpoint -instruction needed; etc). Then write a @file{@var{arch}/tm-@var{os}.h} +instruction needed; etc.). Then write a @file{@var{arch}/tm-@var{os}.h} that just @code{#include}s @file{tm-@var{arch}.h} and @file{config/tm-@var{os}.h}. @@ -2278,12 +2553,13 @@ that just @code{#include}s @file{tm-@var{arch}.h} and @node Target Vector Definition @chapter Target Vector Definition +@cindex target vector -The target vector defines the interface between @value{GDBN}'s abstract handling -of target systems, and the nitty-gritty code that actually exercises -control over a process or a serial port. @value{GDBN} includes some 30-40 -different target vectors; however, each configuration of @value{GDBN} includes -only a few of them. +The target vector defines the interface between @value{GDBN}'s +abstract handling of target systems, and the nitty-gritty code that +actually exercises control over a process or a serial port. +@value{GDBN} includes some 30-40 different target vectors; however, +each configuration of @value{GDBN} includes only a few of them. @section File Targets @@ -2291,39 +2567,40 @@ Both executables and core files have target vectors. @section Standard Protocol and Remote Stubs -@value{GDBN}'s file @file{remote.c} talks a serial protocol to code that runs in -the target system. @value{GDBN} provides several sample ``stubs'' that can be -integrated into target programs or operating systems for this purpose; -they are named @file{*-stub.c}. +@value{GDBN}'s file @file{remote.c} talks a serial protocol to code +that runs in the target system. @value{GDBN} provides several sample +@dfn{stubs} that can be integrated into target programs or operating +systems for this purpose; they are named @file{*-stub.c}. -The @value{GDBN} user's manual describes how to put such a stub into your target -code. What follows is a discussion of integrating the SPARC stub into a -complicated operating system (rather than a simple program), by Stu -Grossman, the author of this stub. +The @value{GDBN} user's manual describes how to put such a stub into +your target code. What follows is a discussion of integrating the +SPARC stub into a complicated operating system (rather than a simple +program), by Stu Grossman, the author of this stub. The trap handling code in the stub assumes the following upon entry to -trap_low: +@code{trap_low}: @enumerate +@item +%l1 and %l2 contain pc and npc respectively at the time of the trap; -@item %l1 and %l2 contain pc and npc respectively at the time of the trap - -@item traps are disabled - -@item you are in the correct trap window +@item +traps are disabled; +@item +you are in the correct trap window. @end enumerate As long as your trap handler can guarantee those conditions, then there -is no reason why you shouldn't be able to `share' traps with the stub. +is no reason why you shouldn't be able to ``share'' traps with the stub. The stub has no requirement that it be jumped to directly from the hardware trap vector. That is why it calls @code{exceptionHandler()}, which is provided by the external environment. For instance, this could -setup the hardware traps to actually execute code which calls the stub +set up the hardware traps to actually execute code which calls the stub first, and then transfers to its own trap handler. For the most point, there probably won't be much of an issue with -`sharing' traps, as the traps we use are usually not used by the kernel, +``sharing'' traps, as the traps we use are usually not used by the kernel, and often indicate unrecoverable error conditions. Anyway, this is all controlled by a table, and is trivial to modify. The most important trap for us is for @code{ta 1}. Without that, we can't single step or @@ -2345,11 +2622,12 @@ They are simply done by deposit/examine operations from @value{GDBN}. @node Native Debugging @chapter Native Debugging +@cindex native debugging Several files control @value{GDBN}'s configuration for native support: @table @file - +@vindex NATDEPFILES @item gdb/config/@var{arch}/@var{xyz}.mh Specifies Makefile fragments needed when hosting @emph{or native} on machine @var{xyz}. In particular, this lists the required @@ -2360,14 +2638,13 @@ define @samp{NAT_CFLAGS}, @samp{NAT_ADD_FILES}, @samp{NAT_CLIBS}, @samp{NAT_CDEPS}, etc.; see @file{Makefile.in}. @item gdb/config/@var{arch}/nm-@var{xyz}.h -(@file{nm.h} is a link to this file, created by configure). Contains C +(@file{nm.h} is a link to this file, created by @code{configure}). Contains C macro definitions describing the native system environment, such as child process control and core file support. @item gdb/@var{xyz}-nat.c Contains any miscellaneous C code required for this native support of this machine. On some machines it doesn't exist at all. - @end table There are some ``generic'' versions of routines that can be used by @@ -2378,11 +2655,10 @@ the @var{xyz} host, you can just include the generic file's name (with Otherwise, if your machine needs custom support routines, you will need to write routines that perform the same functions as the generic file. -Put them into @code{@var{xyz}-nat.c}, and put @code{@var{xyz}-nat.o} +Put them into @file{@var{xyz}-nat.c}, and put @file{@var{xyz}-nat.o} into @code{NATDEPFILES}. @table @file - @item inftarg.c This contains the @emph{target_ops vector} that supports Unix child processes on systems which use ptrace and wait to control the child. @@ -2392,19 +2668,19 @@ This contains the @emph{target_ops vector} that supports Unix child processes on systems which use /proc to control the child. @item fork-child.c -This does the low-level grunge that uses Unix system calls to do a "fork -and exec" to start up a child process. +This does the low-level grunge that uses Unix system calls to do a ``fork +and exec'' to start up a child process. @item infptrace.c This is the low level interface to inferior processes for systems using the Unix @code{ptrace} call in a vanilla way. - @end table @section Native core file Support +@cindex native core files @table @file - +@findex fetch_core_registers @item core-aout.c::fetch_core_registers() Support for reading registers out of a core file. This routine calls @code{register_addr()}, see below. Now that BFD is used to read core @@ -2427,7 +2703,6 @@ the @code{NATDEPFILES} list. If you have your own @code{fetch_core_registers()}, you may not need a separate @code{register_addr()}. Many custom @code{fetch_core_registers()} implementations simply locate the registers themselves.@refill - @end table When making @value{GDBN} run native on a new operating system, to make it @@ -2437,8 +2712,8 @@ code for parsing your OS's core files, or customize machine uses to define the struct of registers that is accessible (possibly in the u-area) in a core file (rather than @file{machine/reg.h}), and an include file that defines whatever header -exists on a core file (e.g. the u-area or a @samp{struct core}). Then -modify @code{trad_unix_core_file_p()} to use these values to set up the +exists on a core file (e.g. the u-area or a @code{struct core}). Then +modify @code{trad_unix_core_file_p} to use these values to set up the section information for the data segment, stack segment, any other segments in the core file (perhaps shared library contents or control information), ``registers'' segment, and if there are two discontiguous @@ -2448,7 +2723,7 @@ standard way, which the section-reading routines in BFD know how to seek around in. Then back in @value{GDBN}, you need a matching routine called -@code{fetch_core_registers()}. If you can use the generic one, it's in +@code{fetch_core_registers}. If you can use the generic one, it's in @file{core-aout.c}; if not, it's in your @file{@var{xyz}-nat.c} file. It will be passed a char pointer to the entire ``registers'' segment, its length, and a zero; or a char pointer to the entire ``regs2'' @@ -2468,19 +2743,21 @@ reading the registers out of processes and out of core files. @section shared libraries @section Native Conditionals +@cindex native conditionals -When @value{GDBN} is configured and compiled, various macros are defined or left -undefined, to control compilation when the host and target systems are -the same. These macros should be defined (or left undefined) in -@file{nm-@var{system}.h}. +When @value{GDBN} is configured and compiled, various macros are +defined or left undefined, to control compilation when the host and +target systems are the same. These macros should be defined (or left +undefined) in @file{nm-@var{system}.h}. @table @code - @item ATTACH_DETACH +@findex ATTACH_DETACH If defined, then @value{GDBN} will include support for the @code{attach} and @code{detach} commands. @item CHILD_PREPARE_TO_STORE +@findex CHILD_PREPARE_TO_STORE If the machine stores all registers at once in the child process, then define this to ensure that all values are correct. This usually entails a read from the child. @@ -2489,32 +2766,37 @@ a read from the child. currently.] @item FETCH_INFERIOR_REGISTERS +@findex FETCH_INFERIOR_REGISTERS Define this if the native-dependent code will provide its own routines @code{fetch_inferior_registers} and @code{store_inferior_registers} in -@file{@var{HOST}-nat.c}. If this symbol is @emph{not} defined, and +@file{@var{host}-nat.c}. If this symbol is @emph{not} defined, and @file{infptrace.c} is included in this configuration, the default routines in @file{infptrace.c} are used for these functions. @item FILES_INFO_HOOK +@findex FILES_INFO_HOOK (Only defined for Convex.) @item FP0_REGNUM +@findex FP0_REGNUM This macro is normally defined to be the number of the first floating point register, if the machine has such registers. As such, it would -appear only in target-specific code. However, /proc support uses this +appear only in target-specific code. However, @file{/proc} support uses this to decide whether floats are in use on this target. @item GET_LONGJMP_TARGET +@findex GET_LONGJMP_TARGET For most machines, this is a target-dependent parameter. On the DECstation and the Iris, this is a native-dependent parameter, since -<setjmp.h> is needed to define it. +@file{setjmp.h} is needed to define it. -This macro determines the target PC address that longjmp() will jump to, +This macro determines the target PC address that @code{longjmp} will jump to, assuming that we have just stopped at a longjmp breakpoint. It takes a -CORE_ADDR * as argument, and stores the target PC value through this +@code{CORE_ADDR *} as argument, and stores the target PC value through this pointer. It examines the current state of the machine as needed. @item KERNEL_U_ADDR +@findex KERNEL_U_ADDR Define this to the address of the @code{u} structure (the ``user struct'', also known as the ``u-page'') in kernel virtual memory. @value{GDBN} needs to know this so that it can subtract this address from absolute @@ -2522,20 +2804,24 @@ addresses in the upage, that are obtained via ptrace or from core files. On systems that don't need this value, set it to zero. @item KERNEL_U_ADDR_BSD +@findex KERNEL_U_ADDR_BSD Define this to cause @value{GDBN} to determine the address of @code{u} at runtime, by using Berkeley-style @code{nlist} on the kernel's image in the root directory. @item KERNEL_U_ADDR_HPUX +@findex KERNEL_U_ADDR_HPUX Define this to cause @value{GDBN} to determine the address of @code{u} at runtime, by using HP-style @code{nlist} on the kernel's image in the root directory. @item ONE_PROCESS_WRITETEXT +@findex ONE_PROCESS_WRITETEXT Define this to be able to, when a breakpoint insertion fails, warn the user that another process may be running with the same executable. -@item PREPARE_TO_PROCEED @var{select_it} +@item PREPARE_TO_PROCEED (@var{select_it}) +@findex PREPARE_TO_PROCEED This (ugly) macro allows a native configuration to customize the way the @code{proceed} function in @file{infrun.c} deals with switching between threads. @@ -2552,51 +2838,64 @@ is required, it returns TRUE. If @var{select_it} is non-zero, it should reselect the old thread. @item PROC_NAME_FMT +@findex PROC_NAME_FMT Defines the format for the name of a @file{/proc} device. Should be defined in @file{nm.h} @emph{only} in order to override the default definition in @file{procfs.c}. @item PTRACE_FP_BUG -mach386-xdep.c +@findex PTRACE_FP_BUG +See @file{mach386-xdep.c}. @item PTRACE_ARG3_TYPE +@findex PTRACE_ARG3_TYPE The type of the third argument to the @code{ptrace} system call, if it exists and is different from @code{int}. @item REGISTER_U_ADDR +@findex REGISTER_U_ADDR Defines the offset of the registers in the ``u area''. @item SHELL_COMMAND_CONCAT +@findex SHELL_COMMAND_CONCAT If defined, is a string to prefix on the shell command used to start the inferior. @item SHELL_FILE +@findex SHELL_FILE If defined, this is the name of the shell to use to run the inferior. Defaults to @code{"/bin/sh"}. -@item SOLIB_ADD (filename, from_tty, targ) +@item SOLIB_ADD (@var{filename}, @var{from_tty}, @var{targ}) +@findex SOLIB_ADD Define this to expand into an expression that will cause the symbols in @var{filename} to be added to @value{GDBN}'s symbol table. @item SOLIB_CREATE_INFERIOR_HOOK +@findex SOLIB_CREATE_INFERIOR_HOOK Define this to expand into any shared-library-relocation code that you want to be run just after the child process has been forked. @item START_INFERIOR_TRAPS_EXPECTED -When starting an inferior, @value{GDBN} normally expects to trap twice; once when +@findex START_INFERIOR_TRAPS_EXPECTED +When starting an inferior, @value{GDBN} normally expects to trap +twice; once when the shell execs, and once when the program itself execs. If the actual number of traps is something other than 2, then define this macro to expand into the number expected. @item SVR4_SHARED_LIBS +@findex SVR4_SHARED_LIBS Define this to indicate that SVR4-style shared libraries are in use. @item USE_PROC_FS +@findex USE_PROC_FS This determines whether small routines in @file{*-tdep.c}, which -translate register values between @value{GDBN}'s internal representation and the -/proc representation, are compiled. +translate register values between @value{GDBN}'s internal +representation and the @file{/proc} representation, are compiled. @item U_REGS_OFFSET +@findex U_REGS_OFFSET This is the offset of the registers in the upage. It need only be defined if the generic ptrace register access routines in @file{infptrace.c} are being used (that is, @file{infptrace.c} is @@ -2606,14 +2905,15 @@ undefined. The default value means that u.u_ar0 @emph{points to} the location of the registers. I'm guessing that @code{#define U_REGS_OFFSET 0} means -that u.u_ar0 @emph{is} the location of the registers. +that @code{u.u_ar0} @emph{is} the location of the registers. @item CLEAR_SOLIB -objfiles.c +@findex CLEAR_SOLIB +See @file{objfiles.c}. @item DEBUG_PTRACE -Define this to debug ptrace calls. - +@findex DEBUG_PTRACE +Define this to debug @code{ptrace} calls. @end table @@ -2622,11 +2922,11 @@ Define this to debug ptrace calls. @chapter Support Libraries @section BFD +@cindex BFD library BFD provides support for @value{GDBN} in several ways: @table @emph - @item identifying executable and core files BFD will identify a variety of file types, including a.out, coff, and several variants thereof, as well as several kinds of core files. @@ -2634,13 +2934,14 @@ several variants thereof, as well as several kinds of core files. @item access to sections of files BFD parses the file headers to determine the names, virtual addresses, sizes, and file locations of all the various named sections in files -(such as the text section or the data section). @value{GDBN} simply calls BFD to -read or write section X at byte offset Y for length Z. +(such as the text section or the data section). @value{GDBN} simply +calls BFD to read or write section @var{x} at byte offset @var{y} for +length @var{z}. @item specialized core file support BFD provides routines to determine the failing command name stored in a core file, the signal with which the program failed, and whether a core -file matches (i.e. could be a core dump of) a particular executable +file matches (i.e.@: could be a core dump of) a particular executable file. @item locating the symbol information @@ -2649,10 +2950,10 @@ symbol information in an executable file or symbol-file. @value{GDBN} itself handles the reading of symbols, since BFD does not ``understand'' debug symbols, but @value{GDBN} uses BFD's cached information to find the symbols, string table, etc. - @end table @section opcodes +@cindex opcodes library The opcodes library provides @value{GDBN}'s disassembler. (It's a separate library because it's also used in binutils, for @file{objdump}). @@ -2664,11 +2965,11 @@ library because it's also used in binutils, for @file{objdump}). @section libiberty @section gnu-regex +@cindex regular expressions library Regex conditionals. @table @code - @item C_ALLOCA @item NFAILURES @@ -2684,7 +2985,6 @@ Regex conditionals. @item Sword @item sparc - @end table @section include @@ -2697,10 +2997,11 @@ This chapter covers topics that are lower-level than the major algorithms of @value{GDBN}. @section Cleanups +@cindex cleanups Cleanups are a structured way to deal with things that need to be done later. When your code does something (like @code{malloc} some memory, -or open a file) that needs to be undone later (e.g. free the memory or +or open a file) that needs to be undone later (e.g., free the memory or close the file), it can make a cleanup. The cleanup will be done at some future point: when the command is finished, when an error occurs, or when your code decides it's time to do cleanups. @@ -2711,10 +3012,10 @@ what they say. This is only done if you ask that it be done. Syntax: @table @code - @item struct cleanup *@var{old_chain}; Declare a variable which will hold a cleanup chain handle. +@findex make_cleanup @item @var{old_chain} = make_cleanup (@var{function}, @var{arg}); Make a cleanup which will cause @var{function} to be called with @var{arg} (a @code{char *}) later. The result, @var{old_chain}, is a @@ -2723,23 +3024,26 @@ handle that can be passed to @code{do_cleanups} or @code{do_cleanups} or @code{discard_cleanups} yourself, you can ignore the result from @code{make_cleanup}. +@findex do_cleanups @item do_cleanups (@var{old_chain}); Perform all cleanups done since @code{make_cleanup} returned @var{old_chain}. E.g.: + @example make_cleanup (a, 0); old = make_cleanup (b, 0); do_cleanups (old); @end example + @noindent will call @code{b()} but will not call @code{a()}. The cleanup that calls @code{a()} will remain in the cleanup chain, and will be done later unless otherwise discarded.@refill +@findex discard_cleanups @item discard_cleanups (@var{old_chain}); Same as @code{do_cleanups} except that it just removes the cleanups from the chain and does not call the specified functions. - @end table Some functions, e.g. @code{fputs_filtered()} or @code{error()}, specify @@ -2750,7 +3054,9 @@ functions, since they might never return to your code (they @samp{longjmp} instead). @section Wrapping Output Lines +@cindex line wrap in output +@findex wrap_here Output that goes through @code{printf_filtered} or @code{fputs_filtered} or @code{fputs_demangled} needs only to have calls to @code{wrap_here} added in places that would be good breaking points. The utility @@ -2764,17 +3070,18 @@ away and used later. It must remain valid until the next call to @code{*_filtered} functions. Don't pass in a local variable and then return! -It is usually best to call @code{wrap_here()} after printing a comma or +It is usually best to call @code{wrap_here} after printing a comma or space. If you call it before printing a space, make sure that your indentation properly accounts for the leading space that will print if the line wraps there. Any function or set of functions that produce filtered output must finish by printing a newline, to flush the wrap buffer, before switching -to unfiltered (``@code{printf}'') output. Symbol reading routines that +to unfiltered (@code{printf}) output. Symbol reading routines that print warnings are a good example. @section @value{GDBN} Coding Standards +@cindex coding standards @value{GDBN} follows the GNU coding standards, as described in @file{etc/standards.texi}. This file is also available for anonymous @@ -2782,9 +3089,10 @@ FTP from GNU archive sites. @value{GDBN} takes a strict interpretation of the standard; in general, when the GNU standard recommends a practice but does not require it, @value{GDBN} requires it. -@value{GDBN} follows an additional set of coding standards specific to @value{GDBN}, -as described in the following sections. +@value{GDBN} follows an additional set of coding standards specific to +@value{GDBN}, as described in the following sections. +@cindex compiler warnings You can configure with @samp{--enable-build-warnings} or @samp{--enable-gdb-build-warnings} to get GCC to check on a number of these rules. @value{GDBN} sources ought not to engender any complaints, @@ -2794,6 +3102,7 @@ warnings is currently @samp{-Wimplicit -Wreturn-type -Wcomment @subsection Formatting +@cindex source code formatting The standard GNU recommendations for formatting must be followed strictly. @@ -2809,17 +3118,18 @@ paren/bracket or before a close paren/bracket. While additional whitespace is generally helpful for reading, do not use more than one blank line to separate blocks, and avoid adding whitespace after the end of a program line (as of 1/99, some 600 lines had whitespace -after the semicolon). Excess whitespace causes difficulties for diff and -patch. +after the semicolon). Excess whitespace causes difficulties for +@code{diff} and @code{patch} utilities. @subsection Comments +@cindex comment formatting The standard GNU requirements on comments must be followed strictly. -Block comments must appear in the following form, with no `/*'- or -'*/'-only lines, and no leading `*': +Block comments must appear in the following form, with no @samp{/*}- or +@samp{*/}-only lines, and no leading @samp{*}: -@example @code +@example /* Wait for control to return from inferior to debugger. If inferior gets a signal, we may decide to start it up again instead of returning. That is why there is a loop in this function. When @@ -2828,7 +3138,7 @@ Block comments must appear in the following form, with no `/*'- or @end example (Note that this format is encouraged by Emacs; tabbing for a multi-line -comment works correctly, and M-Q fills the block consistently.) +comment works correctly, and @kbd{M-q} fills the block consistently.) Put a blank line between the block comments preceding function or variable definitions, and the definition itself. @@ -2840,24 +3150,27 @@ than will fit, and then somebody will have to move it anyhow. @subsection C Usage +@cindex C data types Code must not depend on the sizes of C data types, the format of the host's floating point numbers, the alignment of anything, or the order of evaluation of expressions. +@cindex function usage Use functions freely. There are only a handful of compute-bound areas -in @value{GDBN} that might be affected by the overhead of a function call, mainly -in symbol reading. Most of @value{GDBN}'s performance is limited by the target -interface (whether serial line or system call). +in @value{GDBN} that might be affected by the overhead of a function +call, mainly in symbol reading. Most of @value{GDBN}'s performance is +limited by the target interface (whether serial line or system call). However, use functions with moderation. A thousand one-line functions are just as hard to understand as a single thousand-line function. @subsection Function Prototypes -Prototypes must be used to @emph{declare} functions, and may be used to -@emph{define} them. Prototypes for @value{GDBN} functions must include both the -argument type and name, with the name matching that used in the actual -function definition. +@cindex function prototypes +Prototypes must be used to @emph{declare} functions, and may be used +to @emph{define} them. Prototypes for @value{GDBN} functions must +include both the argument type and name, with the name matching that +used in the actual function definition. All external functions should have a declaration in a header file that callers include, except for @code{_initialize_*} functions, which must @@ -2869,15 +3182,18 @@ source file. @subsection Clean Design +@cindex design In addition to getting the syntax right, there's the little question of semantics. Some things are done in certain ways in @value{GDBN} because long experience has shown that the more obvious ways caused various kinds of trouble. +@cindex assumptions about targets You can't assume the byte order of anything that comes from a target (including @var{value}s, object files, and instructions). Such things -must be byte-swapped using @code{SWAP_TARGET_AND_HOST} in @value{GDBN}, or one of -the swap routines defined in @file{bfd.h}, such as @code{bfd_get_32}. +must be byte-swapped using @code{SWAP_TARGET_AND_HOST} in +@value{GDBN}, or one of the swap routines defined in @file{bfd.h}, +such as @code{bfd_get_32}. You can't assume that you know what interface is being used to talk to the target system. All references to the target must go through the @@ -2890,10 +3206,12 @@ host machine. Target code must bring along its own header files -- written from scratch or explicitly donated by their owner, to avoid copyright problems. +@cindex portability Insertion of new @code{#ifdef}'s will be frowned upon. It's much better to write the code portably than to conditionalize it for various systems. +@cindex system dependencies New @code{#ifdef}'s which test for specific compilers or manufacturers or operating systems are unacceptable. All @code{#ifdef}'s should test for features. The information about which configurations contain which @@ -2920,7 +3238,7 @@ define @code{WRANGLE_SIGNALS} to do the machine-dependent thing. Take a bit of care in defining the hook, so that it can be used by other ports in the future, if they need a hook in the same place. -If the hook is not defined, the code should do whatever "most" machines +If the hook is not defined, the code should do whatever ``most'' machines want. Using @code{#ifdef}, as above, is the preferred way to do this, but sometimes that gets convoluted, in which case use @@ -2930,11 +3248,12 @@ but sometimes that gets convoluted, in which case use #endif @end example +@noindent where the macro is used or in an appropriate header file. Whether to include a @dfn{small} hook, a hook around the exact pieces of code which are system-dependent, or whether to replace a whole function -with a hook depends on the case. A good example of this dilemma can be +with a hook, depends on the case. A good example of this dilemma can be found in @code{get_saved_register}. All machines that @value{GDBN} 2.8 ran on just needed the @code{FRAME_FIND_SAVED_REGS} hook to find the saved registers. Then the SPARC and Pyramid came along, and @@ -2949,41 +3268,44 @@ there is much cleaner than introducing a large number of small hooks. Another way to generalize @value{GDBN} along a particular interface is with an attribute struct. For example, @value{GDBN} has been generalized to handle -multiple kinds of remote interfaces -- not by #ifdef's everywhere, but -by defining the "target_ops" structure and having a current target (as +multiple kinds of remote interfaces---not by @code{#ifdef}s everywhere, but +by defining the @code{target_ops} structure and having a current target (as well as a stack of targets below it, for memory references). Whenever something needs to be done that depends on which remote interface we are -using, a flag in the current target_ops structure is tested (e.g. -`target_has_stack'), or a function is called through a pointer in the +using, a flag in the current target_ops structure is tested (e.g., +@code{target_has_stack}), or a function is called through a pointer in the current target_ops structure. In this way, when a new remote interface -is added, only one module needs to be touched -- the one that actually +is added, only one module needs to be touched---the one that actually implements the new remote interface. Other examples of attribute-structs are BFD access to multiple kinds of object file formats, or @value{GDBN}'s access to multiple source languages. -Please avoid duplicating code. For example, in @value{GDBN} 3.x all the code -interfacing between @code{ptrace} and the rest of @value{GDBN} was duplicated in -@file{*-dep.c}, and so changing something was very painful. In @value{GDBN} 4.x, -these have all been consolidated into @file{infptrace.c}. -@file{infptrace.c} can deal with variations between systems the same way -any system-independent file would (hooks, #if defined, etc.), and -machines which are radically different don't need to use infptrace.c at -all. +Please avoid duplicating code. For example, in @value{GDBN} 3.x all +the code interfacing between @code{ptrace} and the rest of +@value{GDBN} was duplicated in @file{*-dep.c}, and so changing +something was very painful. In @value{GDBN} 4.x, these have all been +consolidated into @file{infptrace.c}. @file{infptrace.c} can deal +with variations between systems the same way any system-independent +file would (hooks, @code{#if defined}, etc.), and machines which are +radically different don't need to use @file{infptrace.c} at all. -Don't put debugging printfs in the code. +Don't put debugging @code{printf}s in the code. @node Porting GDB @chapter Porting @value{GDBN} +@cindex porting to new machines -Most of the work in making @value{GDBN} compile on a new machine is in specifying -the configuration of the machine. This is done in a dizzying variety of -header files and configuration scripts, which we hope to make more -sensible soon. Let's say your new host is called an @var{xyz} (e.g. -@samp{sun4}), and its full three-part configuration name is -@code{@var{arch}-@var{xvend}-@var{xos}} (e.g. @samp{sparc-sun-sunos4}). -In particular: +Most of the work in making @value{GDBN} compile on a new machine is in +specifying the configuration of the machine. This is done in a +dizzying variety of header files and configuration scripts, which we +hope to make more sensible soon. Let's say your new host is called an +@var{xyz} (e.g., @samp{sun4}), and its full three-part configuration +name is @code{@var{arch}-@var{xvend}-@var{xos}} (e.g., +@samp{sparc-sun-sunos4}). In particular: +@itemize @bullet +@item In the top level directory, edit @file{config.sub} and add @var{arch}, @var{xvend}, and @var{xos} to the lists of supported architectures, vendors, and operating systems near the bottom of the file. Also, add @@ -2994,49 +3316,72 @@ running @example ./config.sub @var{xyz} @end example + @noindent and + @example ./config.sub @code{@var{arch}-@var{xvend}-@var{xos}} @end example + @noindent which should both respond with @code{@var{arch}-@var{xvend}-@var{xos}} and no error messages. +@noindent You need to port BFD, if that hasn't been done already. Porting BFD is beyond the scope of this manual. +@item To configure @value{GDBN} itself, edit @file{gdb/configure.host} to recognize your system and set @code{gdb_host} to @var{xyz}, and (unless your desired target is already available) also edit @file{gdb/configure.tgt}, setting @code{gdb_target} to something appropriate (for instance, @var{xyz}). +@item Finally, you'll need to specify and define @value{GDBN}'s host-, native-, and target-dependent @file{.h} and @file{.c} files used for your configuration. +@end itemize @section Configuring @value{GDBN} for Release +@cindex preparing a release +@cindex making a distribution tarball From the top level directory (containing @file{gdb}, @file{bfd}, @file{libiberty}, and so on): + @example make -f Makefile.in gdb.tar.gz @end example +@noindent This will properly configure, clean, rebuild any files that are distributed pre-built (e.g. @file{c-exp.tab.c} or @file{refcard.ps}), and will then make a tarfile. (If the top level directory has already been configured, you can just do @code{make gdb.tar.gz} instead.) This procedure requires: + @itemize @bullet -@item symbolic links -@item @code{makeinfo} (texinfo2 level) -@item @TeX{} -@item @code{dvips} -@item @code{yacc} or @code{bison} + +@item +symbolic links; + +@item +@code{makeinfo} (texinfo2 level); + +@item +@TeX{}; + +@item +@code{dvips}; + +@item +@code{yacc} or @code{bison}. @end itemize + @noindent @dots{} and the usual slew of utilities (@code{sed}, @code{tar}, etc.). @@ -3058,26 +3403,29 @@ or so included files. @node Testsuite @chapter Testsuite +@cindex test suite -The testsuite is an important component of the @value{GDBN} package. While it is -always worthwhile to encourage user testing, in practice this is rarely -sufficient; users typically use only a small subset of the available -commands, and it has proven all too common for a change to cause a -significant regression that went unnoticed for some time. +The testsuite is an important component of the @value{GDBN} package. +While it is always worthwhile to encourage user testing, in practice +this is rarely sufficient; users typically use only a small subset of +the available commands, and it has proven all too common for a change +to cause a significant regression that went unnoticed for some time. -The @value{GDBN} testsuite uses the DejaGNU testing framework. DejaGNU is built -using tcl and expect. The tests themselves are calls to various tcl -procs; the framework runs all the procs and summarizes the passes and -fails. +The @value{GDBN} testsuite uses the DejaGNU testing framework. +DejaGNU is built using @code{Tcl} and @code{expect}. The tests +themselves are calls to various @code{Tcl} procs; the framework runs all the +procs and summarizes the passes and fails. @section Using the Testsuite +@cindex running the test suite To run the testsuite, simply go to the @value{GDBN} object directory (or to the testsuite's objdir) and type @code{make check}. This just sets up some environment variables and invokes DejaGNU's @code{runtest} script. While the testsuite is running, you'll get mentions of which test file is in use, and a mention of any unexpected passes or fails. When the testsuite is finished, you'll get a summary that looks like this: + @example === gdb Summary === @@ -3088,38 +3436,42 @@ finished, you'll get a summary that looks like this: # of unresolved testcases 3 # of untested testcases 5 @end example + The ideal test run consists of expected passes only; however, reality conspires to keep us from this ideal. Unexpected failures indicate -real problems, whether in @value{GDBN} or in the testsuite. Expected failures -are still failures, but ones which have been decided are too hard to -deal with at the time; for instance, a test case might work everywhere -except on AIX, and there is no prospect of the AIX case being fixed in -the near future. Expected failures should not be added lightly, since -you may be masking serious bugs in @value{GDBN}. Unexpected successes are expected -fails that are passing for some reason, while unresolved and untested -cases often indicate some minor catastrophe, such as the compiler being -unable to deal with a test program. - -When making any significant change to @value{GDBN}, you should run the testsuite -before and after the change, to confirm that there are no regressions. -Note that truly complete testing would require that you run the -testsuite with all supported configurations and a variety of compilers; -however this is more than really necessary. In many cases testing with -a single configuration is sufficient. Other useful options are to test -one big-endian (Sparc) and one little-endian (x86) host, a cross config -with a builtin simulator (powerpc-eabi, mips-elf), or a 64-bit host -(Alpha). - -If you add new functionality to @value{GDBN}, please consider adding tests for it -as well; this way future @value{GDBN} hackers can detect and fix their changes -that break the functionality you added. Similarly, if you fix a bug -that was not previously reported as a test failure, please add a test -case for it. Some cases are extremely difficult to test, such as code -that handles host OS failures or bugs in particular versions of -compilers, and it's OK not to try to write tests for all of those. +real problems, whether in @value{GDBN} or in the testsuite. Expected +failures are still failures, but ones which have been decided are too +hard to deal with at the time; for instance, a test case might work +everywhere except on AIX, and there is no prospect of the AIX case +being fixed in the near future. Expected failures should not be added +lightly, since you may be masking serious bugs in @value{GDBN}. +Unexpected successes are expected fails that are passing for some +reason, while unresolved and untested cases often indicate some minor +catastrophe, such as the compiler being unable to deal with a test +program. + +When making any significant change to @value{GDBN}, you should run the +testsuite before and after the change, to confirm that there are no +regressions. Note that truly complete testing would require that you +run the testsuite with all supported configurations and a variety of +compilers; however this is more than really necessary. In many cases +testing with a single configuration is sufficient. Other useful +options are to test one big-endian (Sparc) and one little-endian (x86) +host, a cross config with a builtin simulator (powerpc-eabi, +mips-elf), or a 64-bit host (Alpha). + +If you add new functionality to @value{GDBN}, please consider adding +tests for it as well; this way future @value{GDBN} hackers can detect +and fix their changes that break the functionality you added. +Similarly, if you fix a bug that was not previously reported as a test +failure, please add a test case for it. Some cases are extremely +difficult to test, such as code that handles host OS failures or bugs +in particular versions of compilers, and it's OK not to try to write +tests for all of those. @section Testsuite Organization +@cindex test suite organization The testsuite is entirely contained in @file{gdb/testsuite}. While the testsuite includes some makefiles and configury, these are very minimal, and used for little besides cleaning up, since the tests themselves @@ -3141,43 +3493,38 @@ located, and since each test file sets up its own compilation and execution environment, this organization is simply for convenience and intelligibility. -@table @code - +@table @file @item gdb.base - This is the base testsuite. The tests in it should apply to all configurations of @value{GDBN} (but generic native-only tests may live here). The test programs should be in the subset of C that is valid K&R, -ANSI/ISO, and C++ (ifdefs are allowed if necessary, for instance +ANSI/ISO, and C++ (@code{#ifdef}s are allowed if necessary, for instance for prototypes). @item gdb.@var{lang} - -Language-specific tests for all languages besides C. Examples are +Language-specific tests for any language @var{lang} besides C. Examples are @file{gdb.c++} and @file{gdb.java}. @item gdb.@var{platform} - Non-portable tests. The tests are specific to a specific configuration (host or target), such as HP-UX or eCos. Example is @file{gdb.hp}, for HP-UX. @item gdb.@var{compiler} - Tests specific to a particular compiler. As of this writing (June 1999), there aren't currently any groups of tests in this category that couldn't just as sensibly be made platform-specific, but one could -imagine a gdb.gcc, for tests of @value{GDBN}'s handling of GCC extensions. +imagine a @file{gdb.gcc}, for tests of @value{GDBN}'s handling of GCC +extensions. @item gdb.@var{subsystem} - Tests that exercise a specific @value{GDBN} subsystem in more depth. For instance, @file{gdb.disasm} exercises various disassemblers, while @file{gdb.stabs} tests pathways through the stabs symbol reader. - @end table @section Writing Tests +@cindex writing tests In many areas, the @value{GDBN} tests are already quite comprehensive; you should be able to copy existing tests to handle new cases. @@ -3239,10 +3586,10 @@ also documents all the available macros. @c Conditionals}, @pxref{Native Conditionals}, and @pxref{Obsolete @c Conditionals}) -Start with the header files. Once you have some idea of how @value{GDBN}'s internal -symbol tables are stored (see @file{symtab.h}, @file{gdbtypes.h}), you -will find it much easier to understand the code which uses and creates -those symbol tables. +Start with the header files. Once you have some idea of how +@value{GDBN}'s internal symbol tables are stored (see @file{symtab.h}, +@file{gdbtypes.h}), you will find it much easier to understand the +code which uses and creates those symbol tables. You may wish to process the information you are getting somehow, to enhance your understanding of it. Summarize it, translate it to another @@ -3271,19 +3618,22 @@ principle applies---when the code you are looking at calls something else, just try to understand generally what the code being called does, rather than worrying about all its details. -A good place to start when tracking down some particular area is with a -command which invokes that feature. Suppose you want to know how -single-stepping works. As a @value{GDBN} user, you know that the @code{step} -command invokes single-stepping. The command is invoked via command -tables (see @file{command.h}); by convention the function which actually -performs the command is formed by taking the name of the command and -adding @samp{_command}, or in the case of an @code{info} subcommand, -@samp{_info}. For example, the @code{step} command invokes the -@code{step_command} function and the @code{info display} command invokes -@code{display_info}. When this convention is not followed, you might -have to use @code{grep} or @kbd{M-x tags-search} in emacs, or run @value{GDBN} on -itself and set a breakpoint in @code{execute_command}. - +@cindex command implementation +A good place to start when tracking down some particular area is with +a command which invokes that feature. Suppose you want to know how +single-stepping works. As a @value{GDBN} user, you know that the +@code{step} command invokes single-stepping. The command is invoked +via command tables (see @file{command.h}); by convention the function +which actually performs the command is formed by taking the name of +the command and adding @samp{_command}, or in the case of an +@code{info} subcommand, @samp{_info}. For example, the @code{step} +command invokes the @code{step_command} function and the @code{info +display} command invokes @code{display_info}. When this convention is +not followed, you might have to use @code{grep} or @kbd{M-x +tags-search} in emacs, or run @value{GDBN} on itself and set a +breakpoint in @code{execute_command}. + +@cindex @code{bug-gdb} mailing list If all of the above fail, it may be appropriate to ask for information on @code{bug-gdb}. But @emph{never} post a generic question like ``I was wondering if anyone could give me some tips about understanding @@ -3293,13 +3643,14 @@ Suggestions for improving the manual are always welcome, of course. @node Debugging GDB,,,Hints @section Debugging @value{GDBN} with itself +@cindex debugging @value{GDBN} If @value{GDBN} is limping on your machine, this is the preferred way to get it fully functional. Be warned that in some ancient Unix systems, like Ultrix 4.2, a program can't be running in one process while it is being -debugged in another. Rather than typing the command @code{@w{./gdb +debugged in another. Rather than typing the command @kbd{@w{./gdb ./gdb}}, which works on Suns and such, you can copy @file{gdb} to -@file{gdb2} and then type @code{@w{./gdb ./gdb2}}. +@file{gdb2} and then type @kbd{@w{./gdb ./gdb2}}. When you run @value{GDBN} in the @value{GDBN} source directory, it will read a @file{.gdbinit} file that sets up some simple things to make debugging @@ -3317,6 +3668,7 @@ have run @code{fixincludes} if you are compiling with gcc. @section Submitting Patches +@cindex submitting patches Thanks for thinking of offering your changes back to the community of @value{GDBN} users. In general we like to get well designed enhancements. Thanks also for checking in advance about the best way to transfer the @@ -3329,31 +3681,33 @@ If the maintainers don't have time to put the patch in when it arrives, or if there is any question about a patch, it goes into a large queue with everyone else's patches and bug reports. +@cindex legal papers for code contributions The legal issue is that to incorporate substantial changes requires a copyright assignment from you and/or your employer, granting ownership of the changes to the Free Software Foundation. You can get the standard documents for doing this by sending mail to @code{gnu@@gnu.org} and asking for it. We recommend that people write in "All programs owned by the Free Software Foundation" as "NAME OF PROGRAM", so that -changes in many programs (not just @value{GDBN}, but GAS, Emacs, GCC, etc) can be +changes in many programs (not just @value{GDBN}, but GAS, Emacs, GCC, +etc) can be contributed with only one piece of legalese pushed through the bureacracy and filed with the FSF. We can't start merging changes until this paperwork is received by the FSF (their rules, which we follow since we maintain it for them). Technically, the easiest way to receive changes is to receive each -feature as a small context diff or unidiff, suitable for "patch". Each -message sent to me should include the changes to C code and header files -for a single feature, plus ChangeLog entries for each directory where -files were modified, and diffs for any changes needed to the manuals -(gdb/doc/gdb.texinfo or gdb/doc/gdbint.texinfo). If there are a lot of -changes for a single feature, they can be split down into multiple -messages. +feature as a small context diff or unidiff, suitable for @code{patch}. +Each message sent to me should include the changes to C code and +header files for a single feature, plus @file{ChangeLog} entries for +each directory where files were modified, and diffs for any changes +needed to the manuals (@file{gdb/doc/gdb.texinfo} or +@file{gdb/doc/gdbint.texinfo}). If there are a lot of changes for a +single feature, they can be split down into multiple messages. In this way, if we read and like the feature, we can add it to the sources with a single patch command, do some testing, and check it in. -If you leave out the ChangeLog, we have to write one. If you leave -out the doc, we have to puzzle out what needs documenting. Etc. +If you leave out the @file{ChangeLog}, we have to write one. If you leave +out the doc, we have to puzzle out what needs documenting. Etc., etc. The reason to send each change in a separate message is that we will not install some of the changes. They'll be returned to you with questions @@ -3375,17 +3729,17 @@ they arrive. The others go into a queue and get installed as time permits, which, since the maintainers have many demands to meet, may not be for quite some time. -Please send patches directly to the @value{GDBN} maintainers at -@code{gdb-patches@@sourceware.cygnus.com}. +Please send patches directly to +@email{gdb-patches@@sourceware.cygnus.com, the @value{GDBN} maintainers}. @section Obsolete Conditionals +@cindex obsolete code Fragments of old code in @value{GDBN} sometimes reference or set the following configuration macros. They should not be used by new code, and old uses should be removed as those parts of the debugger are otherwise touched. @table @code - @item STACK_END_ADDR This macro used to define where the end of the stack appeared, for use in interpreting core file formats that don't record this address in the @@ -3409,6 +3763,11 @@ exec.c @end table +@node Index +@unnumbered Index + +@printindex cp + @c TeX can handle the contents at the start but makeinfo 3.12 can not @ifinfo @contents |