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| -rw-r--r-- | gdb/doc/ChangeLog | 6 | ||||
| -rw-r--r-- | gdb/doc/stabs.texinfo | 140 |
2 files changed, 89 insertions, 57 deletions
diff --git a/gdb/doc/ChangeLog b/gdb/doc/ChangeLog index 413cbf3..3411981 100644 --- a/gdb/doc/ChangeLog +++ b/gdb/doc/ChangeLog @@ -1,3 +1,9 @@ +Sun Apr 18 09:47:45 1993 Jim Kingdon (kingdon@cygnus.com) + + * stabs.texinfo (Symbol descriptors): Re-do using @table and @xref. + (Parameters): Rewrite. + (xcoff-differences, Sun-differences): Minor changes. + Thu Apr 15 02:35:24 1993 John Gilmore (gnu@cacophony.cygnus.com) * stabs.texinfo: Minor cleanup. diff --git a/gdb/doc/stabs.texinfo b/gdb/doc/stabs.texinfo index 6fc7a0c..fc19d5e 100644 --- a/gdb/doc/stabs.texinfo +++ b/gdb/doc/stabs.texinfo @@ -983,56 +983,58 @@ The stab for @code{s_flap} is located just before the @code{N_LBRAC} for @node Parameters @section Parameters -@table @strong -@item Directive: -@code{.stabs} -@item Type: -@code{N_PSYM} -@item Symbol Descriptor: -@code{p} -@end table +The symbol descriptor @samp{p} is used to refer to parameters which are +in the arglist. They follow the symbol that represents the procedure +itself. The value of the symbol is the offset relative to the argument +list. -Procedure parameters are represented by the N_PSYM stab type. The -following source lines show the parameters of the main routine. +If the parameter is passed in a register, or is allocated as a local +variable rather than an argument (the latter distinction is important +for machines in which the argument list offset is relative to something +different from a local variable offset), then the traditional way to do +this is to provide two symbols for each argument: @example -17 main (argc, argv) -18 int argc; -19 char* argv[]; -20 @{ +.stabs "arg:p1" . . . +.stabs "arg:r1" . . . @end example -The N_PSYM stabs describing parameters to a function directly follow -the N_FUN stab that represents the procedure itself. The N_FUN stab -immediately follows the code of the procedure it describes. Following -the N_PSYM parameter stabs are any N_LSYM stabs representing local -variables. +Debuggers are expected to use the second one to find the value, and the +first one to know that it is an argument. -@example -@exdent <36> N_FUN - describing the procedure main +Because this is kind of ugly, some compilers use symbol descriptor @samp{P} +or @samp{R} to indicate an argument which is in a register. The symbol +value is the register number. @samp{P} and @samp{R} mean the same +thing, the difference is that @samp{P} is a GNU invention and @samp{R} +is an IBM (xcoff) invention. As of version 4.9, GDB should handle +either one. -94 .stabs "main:F1",36,0,0,_main +There is no symbol descriptor analogous to @samp{P} for local variables. +Some compilers are said to use the pair of symbols approach described +above, but I don't know which ones. On the intel 960, the type of the +variable indicates whether a @samp{p} symbol's value is an the argument +list offset or a local variable offset. -@exdent <160> N_PSYM - parameters -@exdent .stabs "name:sym_desc(value_param)type_ref(int)", N_PSYM, -@exdent NIL, NIL, frame_ptr_offset +As a simple example, the code -95 .stabs "argc:p1",160,0,0,68 - -@exdent <160> N_PSYM - parameter -@exdent .stabs "name:sym_desc(value_param)type_def(20)=ptr_to type_def(21)= -@exdent ptr_to type_ref(char) +@example +17 main (argc, argv) +18 int argc; +19 char **argv; +20 @{ +@end example + +produces the stabs +@example +94 .stabs "main:F1",36,0,0,_main ; 36 is N_FUN +95 .stabs "argc:p1",160,0,0,68 ; 160 is N_PSYM 96 .stabs "argv:p20=*21=*2",160,0,0,72 @end example -The type definition of argv is interesting because it defines two new -types in terms of an existing one. The ``array'' argv is really a -pointer, according to C language rules, since it is declared as a -parameter. Its element type is character pointers. Thus the type of -argv is ptr to ptr to char. The stab for argv contains nested -type_definitions. Type 21 is ptr to type 2 (char) and argv (type 20) -is ptr to type 21. +The type definition of argv is interesting because it contains several +type definitions. Type 21 is ptr to type 2 (char) and argv (type 20) is +ptr to type 21. @node Aggregate Types @chapter Aggregate Types @@ -2417,20 +2419,43 @@ n_type n_type name used to describe @node Symbol descriptors @section Table C: Symbol descriptors -@example -descriptor meaning -------------------------------------------------- -(empty) local variable - f local function - F global function - G global variable - p value parameter - r register variable - S static global variable - t type name - T enumeration, struct or type tag - V static local variable -@end example +@table @code +@item (empty) +Local variable, @xref{Automatic variables}. + +@item f +Local function, @xref{Procedures}. + +@item F +Global function, @xref{Procedures}. + +@item t +Type name, @xref{Typedefs}. + +@item T +enumeration, struct or union tag, @xref{Unions}. + +@item G +Global variable, @xref{Global Variables}. + +@item r +Register variable, @xref{Register variables}. + +@item S +Static file scope variable @xref{Initialized statics}, +@xref{Un-initialized static variables}. + +@item V +Static procedure scope variable @xref{Initialized statics}, +@xref{Un-initialized static variables}. + +@item p +Argument list parameter @xref{Parameters}. + +@item P +@item R +Register parameter @xref{Parameters}. +@end table @node Type Descriptors @section Table D: Type Descriptors @@ -3019,7 +3044,10 @@ dbx? @node xcoff-differences @appendix Differences between GNU stabs in a.out and GNU stabs in xcoff -(The AIX/RS6000 native object file format is xcoff with stabs) +@c FIXME: Merge *all* these into the main body of the document. +(The AIX/RS6000 native object file format is xcoff with stabs). This +appendix only covers those differences which are not covered in the main +body of this document. @itemize @bullet @item @@ -3081,10 +3109,6 @@ the end marked with .ei "filename" @item If the xcoff stab is a N_FUN (C_FUN) then follow the string field with ,. instead of just , - -@item -The symbol descriptor for register parameters is P for a.out and R for -xcoff. @end itemize @@ -3136,6 +3160,8 @@ N_LENG unknown @node Sun-differences @appendix Differences between GNU stabs and Sun native stabs. +@c FIXME: Merge all this stuff into the main body of the document. + @itemize @bullet @item GNU C stabs define *all* types, file or procedure scope, as @@ -3144,7 +3170,7 @@ N_LSYM. Sun doc talks about using N_GSYM too. @item Stabs describing block scopes, N_LBRAC and N_RBRAC are supposed to contain the nesting level of the block in the desc field, re Sun doc. -GNU stabs always have 0 in that field. +GNU stabs always have 0 in that field. dbx seems not to care. @item Sun C stabs use type number pairs in the format (a,b) where a is a |