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2023-06-05gdb: building inferior strings from within GDBAndrew Burgess1-12/+11
History Of This Patch ===================== This commit aims to address PR gdb/21699. There have now been a couple of attempts to fix this issue. Simon originally posted two patches back in 2021: https://sourceware.org/pipermail/gdb-patches/2021-July/180894.html https://sourceware.org/pipermail/gdb-patches/2021-July/180896.html Before Pedro then posted a version of his own: https://sourceware.org/pipermail/gdb-patches/2021-July/180970.html After this the conversation halted. Then in 2023 I (Andrew) also took a look at this bug and posted two versions: https://sourceware.org/pipermail/gdb-patches/2023-April/198570.html https://sourceware.org/pipermail/gdb-patches/2023-April/198680.html The approach taken in my first patch was pretty similar to what Simon originally posted back in 2021. My second attempt was only a slight variation on the first. Pedro then pointed out his older patch, and so we arrive at this patch. The GDB changes here are mostly Pedro's work, but updated by me (Andrew), any mistakes are mine. The tests here are a combinations of everyone's work, and the commit message is new, but copies bits from everyone's earlier work. Problem Description =================== Bug PR gdb/21699 makes the observation that using $_as_string with GDB's printf can cause GDB to print unexpected data from the inferior. The reproducer is pretty simple: #include <stddef.h> static char arena[100]; /* Override malloc() so value_coerce_to_target() gets a known pointer, and we know we"ll see an error if $_as_string() gives a string that isn't null terminated. */ void *malloc (size_t size) { memset (arena, 'x', sizeof (arena)); if (size > sizeof (arena)) return NULL; return arena; } int main () { return 0; } And then in a GDB session: $ gdb -q test Reading symbols from /tmp/test... (gdb) start Temporary breakpoint 1 at 0x4004c8: file test.c, line 17. Starting program: /tmp/test Temporary breakpoint 1, main () at test.c:17 17 return 0; (gdb) printf "%s\n", $_as_string("hello") "hello"xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx (gdb) quit The problem above is caused by how value_cstring is used within py-value.c, but once we understand the issue then it turns out that value_cstring is used in an unexpected way in many places within GDB. Within py-value.c we have a null-terminated C-style string. We then pass a pointer to this string, along with the length of this string (so not including the null-character) to value_cstring. In value_cstring GDB allocates an array value of the given character type, and copies in requested number of characters. However value_cstring does not add a null-character of its own. This means that the value created by calling value_cstring is only null-terminated if the null-character is included in the passed in length. In py-value.c this is not the case, and indeed, in most uses of value_cstring, this is not the case. When GDB tries to print one of these strings the value contents are pushed to the inferior, and then read back as a C-style string, that is, GDB reads inferior memory until it finds a null-terminator. For the py-value.c case, no null-terminator is pushed into the inferior, so GDB will continue reading inferior memory until a null-terminator is found, with unpredictable results. Patch Description ================= The first thing this patch does is better define what the arguments for the two function value_cstring and value_string should represent. The comments in the header file are updated to describe whether the length argument should, or should not, include a null-character. Also, the data argument is changed to type gdb_byte. The functions as they currently exist will handle wide-characters, in which case more than one 'char' would be needed for each character. As such using gdb_byte seems to make more sense. To avoid adding casts throughout GDB, I've also added an overload that still takes a 'char *', but asserts that the character type being used is of size '1'. The value_cstring function is now responsible for adding a null character at the end of the string value it creates. However, once we start looking at how value_cstring is used, we realise there's another, related, problem. Not every language's strings are null terminated. Fortran and Ada strings, for example, are just an array of characters, GDB already has the function value_string which can be used to create such values. Consider this example using current GDB: (gdb) set language ada (gdb) p $_gdb_setting("arch") $1 = (97, 117, 116, 111) (gdb) ptype $ type = array (1 .. 4) of char (gdb) p $_gdb_maint_setting("test-settings string") $2 = (0) (gdb) ptype $ type = array (1 .. 1) of char This shows two problems, first, the $_gdb_setting and $_gdb_maint_setting functions are calling value_cstring using the builtin_char character, rather than a language appropriate type. In the first call, the 'arch' case, the value_cstring call doesn't include the null character, so the returned array only contains the expected characters. But, in the $_gdb_maint_setting example we do end up including the null-character, even though this is not expected for Ada strings. This commit adds a new language method language_defn::value_string, this function takes a pointer and length and creates a language appropriate value that represents the string. For C, C++, etc this will be a null-terminated string (by calling value_cstring), and for Fortran and Ada this can be a bounded array of characters with no null terminator. Additionally, this new language_defn::value_string function is responsible for selecting a language appropriate character type. After this commit the only calls to value_cstring are from the C expression evaluator and from the default language_defn::value_string. And the only calls to value_string are from Fortan, Ada, and ObjectC related code. Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=21699 Co-Authored-By: Simon Marchi <simon.marchi@efficios.com> Co-Authored-By: Andrew Burgess <aburgess@redhat.com> Co-Authored-By: Pedro Alves <pedro@palves.net> Approved-By: Simon Marchi <simon.marchi@efficios.com>
2023-06-03[gdb] Fix typosTom de Vries1-1/+1
Fix a few typos: - implemention -> implementation - convertion(s) -> conversion(s) - backlashes -> backslashes - signoring -> ignoring - (un)ambigious -> (un)ambiguous - occured -> occurred - hidding -> hiding - temporarilly -> temporarily - immediatelly -> immediately - sillyness -> silliness - similiar -> similar - porkuser -> pokeuser - thats -> that - alway -> always - supercede -> supersede - accomodate -> accommodate - aquire -> acquire - priveleged -> privileged - priviliged -> privileged - priviledges -> privileges - privilige -> privilege - recieve -> receive - (p)refered -> (p)referred - succesfully -> successfully - successfuly -> successfully - responsability -> responsibility - wether -> whether - wich -> which - disasbleable -> disableable - descriminant -> discriminant - construcstor -> constructor - underlaying -> underlying - underyling -> underlying - structureal -> structural - appearences -> appearances - terciarily -> tertiarily - resgisters -> registers - reacheable -> reachable - likelyhood -> likelihood - intepreter -> interpreter - disassemly -> disassembly - covnersion -> conversion - conviently -> conveniently - atttribute -> attribute - struction -> struct - resonable -> reasonable - popupated -> populated - namespaxe -> namespace - intialize -> initialize - identifer(s) -> identifier(s) - expection -> exception - exectuted -> executed - dungerous -> dangerous - dissapear -> disappear - completly -> completely - (inter)changable -> (inter)changeable - beakpoint -> breakpoint - automativ -> automatic - alocating -> allocating - agressive -> aggressive - writting -> writing - reguires -> requires - registed -> registered - recuding -> reducing - opeartor -> operator - ommitted -> omitted - modifing -> modifying - intances -> instances - imbedded -> embedded - gdbaarch -> gdbarch - exection -> execution - direcive -> directive - demanged -> demangled - decidely -> decidedly - argments -> arguments - agrument -> argument - amespace -> namespace - targtet -> target - supress(ed) -> suppress(ed) - startum -> stratum - squence -> sequence - prompty -> prompt - overlow -> overflow - memember -> member - languge -> language - geneate -> generate - funcion -> function - exising -> existing - dinking -> syncing - destroh -> destroy - clenaed -> cleaned - changep -> changedp (name of variable) - arround -> around - aproach -> approach - whould -> would - symobl -> symbol - recuse -> recurse - outter -> outer - freeds -> frees - contex -> context Tested on x86_64-linux. Reviewed-By: Tom Tromey <tom@tromey.com>
2023-05-01Replace field_is_static with a methodTom Tromey1-3/+3
This changes field_is_static to be a method on struct field, and updates all the callers. Most of this patch was written by script. Regression tested on x86-64 Fedora 36.
2023-03-29Pass a frame to value_at_lazy and value_from_contents_and_addressTom Tromey1-5/+6
This patch adds a 'frame' parameter to value_at_lazy and ensures that it is passed down to the call to resolve_dynamic_type. This required also adding a frame parameter to value_from_contents_and_address. Nothing passes this parameter to value_at_lazy yet, so this patch should have no visible effect.
2023-03-27Use gdb_gmp for scalar arithmeticTom Tromey1-6/+8
This changes gdb to use scalar arithmetic for expression evaluation. I suspect this patch is not truly complete, as there may be code paths that still don't correctly handle 128-bit integers. However, many things do work now. Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30190
2023-03-18Use type allocator for array typesTom Tromey1-2/+2
This changes the array type creation functions to accept a type allocator, and updates all the callers. Note that symbol readers should generally allocate on the relevant objfile, regardless of the placement of the index type of the array, which is what this patch implements. Reviewed-By: Simon Marchi <simon.marchi@efficios.com>
2023-03-18Use type allocator for range typesTom Tromey1-2/+4
This changes the range type creation functions to accept a type allocator, and updates all the callers. Note that symbol readers should generally allocate on the relevant objfile, regardless of the underlying type of the range, which is what this patch implements. Reviewed-By: Simon Marchi <simon.marchi@efficios.com>
2023-03-14Add operators and methods to gdb_mpqTom Tromey1-9/+4
This adds some operators and methods to gdb_mpq, in preparation for making its implementation private. This only adds the operators currently needed by gdb. More could be added as necessary.
2023-03-14Add methods and operators to gdb_mpzTom Tromey1-1/+1
This adds various methods and operators to gdb_mpz, as a step toward hiding the implementation. This only adds the operators that were needed. Many more could be added as required.
2023-02-15Change value::m_stack to boolTom Tromey1-1/+1
This changes value::m_stack to be a bool and updates the various uses. Reviewed-By: Bruno Larsen <blarsen@redhat.com>
2023-02-15Change value::m_lazy to boolTom Tromey1-1/+1
This changes value::m_lazy to be a bool and updates the various uses. Reviewed-By: Bruno Larsen <blarsen@redhat.com>
2023-02-13Remove deprecated_lval_hackTom Tromey1-17/+17
This removes deprecated_lval_hack and the VALUE_LVAL macro, replacing all uses with a call to value::lval. Approved-By: Simon Marchi <simon.marchi@efficios.com>
2023-02-13Introduce set_lval method on valueTom Tromey1-2/+2
This introduces the set_lval method on value, one step toward removing deprecated_lval_hack. Ultimately I think the goal should be for some of these set_* methods to be replaced with constructors; but I haven't done this, as the series is already too long. Other 'deprecated' methods can probably be handled the same way. Approved-By: Simon Marchi <simon.marchi@efficios.com>
2023-02-13Turn various value copying-related functions into methodsTom Tromey1-8/+7
This patch turns a grab bag of value functions to methods of value. These are done together because their implementations are interrelated. Approved-By: Simon Marchi <simon.marchi@efficios.com>
2023-02-13Turn some xmethod functions into methodsTom Tromey1-1/+1
This turns value_from_xmethod, result_type_of_xmethod, and call_xmethod to be methods of value. value_from_xmethod is a static "constructor" now. Approved-By: Simon Marchi <simon.marchi@efficios.com>
2023-02-13Turn set_value_component_location into methodTom Tromey1-1/+1
This turns set_value_component_location into a method of value. Approved-By: Simon Marchi <simon.marchi@efficios.com>
2023-02-13Turn many optimized-out value functions into methodsTom Tromey1-3/+3
This turns many functions that are related to optimized-out or availability-checking to be methods of value. The static function value_entirely_covered_by_range_vector is also converted to be a private method. Approved-By: Simon Marchi <simon.marchi@efficios.com>
2023-02-13Turn value_copy into a methodTom Tromey1-7/+7
This turns value_copy into a method of value. Much of this was written by script. Approved-By: Simon Marchi <simon.marchi@efficios.com>
2023-02-13Turn remaining value_contents functions into methodsTom Tromey1-23/+23
This turns the remaining value_contents functions -- value_contents, value_contents_all, value_contents_for_printing, and value_contents_for_printing_const -- into methods of value. It also converts the static functions require_not_optimized_out and require_available to be private methods. Approved-By: Simon Marchi <simon.marchi@efficios.com>
2023-02-13Turn value_bits_synthetic_pointer into a methodTom Tromey1-2/+2
This changes value_bits_synthetic_pointer to be a method of value. Approved-By: Simon Marchi <simon.marchi@efficios.com>
2023-02-13Turn value_fetch_lazy into a methodTom Tromey1-1/+1
This changes value_fetch_lazy to be a method of value. A few helper functions are converted as well, to avoid problems in later patches when the data members are all made private. Approved-By: Simon Marchi <simon.marchi@efficios.com>
2023-02-13Turn some value_contents functions into methodsTom Tromey1-16/+16
This turns value_contents_raw, value_contents_writeable, and value_contents_all_raw into methods on value. The remaining functions will be changed later in the series; they were a bit trickier and so I didn't include them in this patch. Approved-By: Simon Marchi <simon.marchi@efficios.com>
2023-02-13Turn value_zero into static "constructor"Tom Tromey1-5/+5
This turns value_zero into a static "constructor" of value. Approved-By: Simon Marchi <simon.marchi@efficios.com>
2023-02-13Turn allocate_value into a static "constructor"Tom Tromey1-18/+18
This changes allocate_value to be a static "constructor" of value. Approved-By: Simon Marchi <simon.marchi@efficios.com>
2023-02-13Turn allocate_value_lazy into a static "constructor"Tom Tromey1-1/+1
This changes allocate_value_lazy to be a static "constructor" of struct value. I considered trying to change value to use ordinary new/delete, but it seems to me that due to reference counting, we may someday want to change these static constructors to return value_ref_ptr instead. Approved-By: Simon Marchi <simon.marchi@efficios.com>
2023-02-13Turn value_address and set_value_address functions into methodsTom Tromey1-22/+22
This changes the value_address and set_value_address functions to be methods of value. Approved-By: Simon Marchi <simon.marchi@efficios.com>
2023-02-13Turn value_computed_closure and value_computed_funcs functions into methodsTom Tromey1-2/+2
This changes the value_computed_funcs and value_computed_closure functions to be methods of value. Approved-By: Simon Marchi <simon.marchi@efficios.com>
2023-02-13Turn value_stack and set_value_stack functions into methodsTom Tromey1-1/+1
This changes the value_stack and set_value_stack functions to be methods of value. Approved-By: Simon Marchi <simon.marchi@efficios.com>
2023-02-13Turn value_lazy and set_value_lazy functions into methodsTom Tromey1-3/+3
This changes the value_lazy and set_value_lazy functions to be methods of value. Much of this patch was written by script. Approved-By: Simon Marchi <simon.marchi@efficios.com>
2023-02-13Turn some value offset functions into methodTom Tromey1-20/+20
This changes various offset-related functions to be methods of value. Much of this patch was written by script. Approved-By: Simon Marchi <simon.marchi@efficios.com>
2023-02-13Turn value_enclosing_type into methodTom Tromey1-17/+16
This changes value_enclosing_type to be a method of value. Much of this patch was written by script. Approved-By: Simon Marchi <simon.marchi@efficios.com>
2023-02-13Turn deprecated_value_modifiable into methodTom Tromey1-1/+1
This changes deprecated_value_modifiable to be a method of value. Approved-By: Simon Marchi <simon.marchi@efficios.com>
2023-02-13Turn value_offset into methodTom Tromey1-9/+9
This changes value_offset to be a method of value. Much of this patch was written by script. Approved-By: Simon Marchi <simon.marchi@efficios.com>
2023-02-13Turn value_parent into methodTom Tromey1-5/+5
This changes value_parent to be a method of value. Much of this patch was written by script. Approved-By: Simon Marchi <simon.marchi@efficios.com>
2023-02-13Turn value_bitpos into methodTom Tromey1-5/+5
This changes value_bitpos to be a method of value. Much of this patch was written by script. Approved-By: Simon Marchi <simon.marchi@efficios.com>
2023-02-13Turn value_bitsize into methodTom Tromey1-12/+12
This changes value_bitsize to be a method of value. Much of this patch was written by script. Approved-By: Simon Marchi <simon.marchi@efficios.com>
2023-02-13Turn value_arch into methodTom Tromey1-1/+1
This changes value_arch to be a method of value. Much of this patch was written by script. Approved-By: Simon Marchi <simon.marchi@efficios.com>
2023-02-13Turn deprecated_set_value_type into a methodTom Tromey1-10/+9
This changes deprecated_set_value_type to be a method of value. Much of this patch was written by script. Approved-By: Simon Marchi <simon.marchi@efficios.com>
2023-02-13Turn value_type into methodTom Tromey1-63/+63
This changes value_type to be a method of value. Much of this patch was written by script. Approved-By: Simon Marchi <simon.marchi@efficios.com>
2023-01-03Introduce value_at_non_lvalTom Tromey1-0/+10
In some cases, while a value might be read from memory, gdb should not record the value as being equivalent to that memory. In Ada, the inferior call code will call ada_convert_actual -- and here, if the argument is already in memory, that address will simply be reused. However, for a call like "f(g())", the result of "g" might be on the stack and thus overwritten by the call to "f". This patch introduces a new function that is like value_at but that ensures that the result is non-lvalue.
2023-01-01Update copyright year range in header of all files managed by GDBJoel Brobecker1-1/+1
This commit is the result of running the gdb/copyright.py script, which automated the update of the copyright year range for all source files managed by the GDB project to be updated to include year 2023.
2022-11-10gdb: Fix regressions caused by 041de3d73aa121f2ff0c077213598963bfb34b79Bruno Larsen1-2/+2
Commit 041de3d73aa changed the output format of all error messages when GDB couldn't determine a compatible overload for a given function, but it was only supposed to change if the failure happened due to incomplete types. This commit removes the stray . that was added
2022-11-10gdb/c++: Improve error messages in overload resolutionBruno Larsen1-4/+49
When resolving overloaded functions, GDB relies on knowing relationships between types, i.e. if a type inherits from another. However, some compilers may not add complete information for given types as a way to reduce unnecessary debug information. In these cases, GDB would just say that it couldn't resolve the method or function, with no extra information. The problem is that sometimes the user may not know that the type information is incomplete, and may just assume that there is a bug in GDB. To improve the user experience, we attempt to detect if the overload match failed because of an incomplete type, and warn the user of this. This commit also adds a testcase confirming that the message is only triggered in the correct scenario. This test was not developed as an expansion of gdb.cp/overload.cc because it needed the dwarf assembler, and porting all of overload.cc seemed unnecessary. Approved-By: Tom Tromey <tom@tromey.com>
2022-10-19internal_error: remove need to pass __FILE__/__LINE__Pedro Alves1-3/+2
Currently, every internal_error call must be passed __FILE__/__LINE__ explicitly, like: internal_error (__FILE__, __LINE__, "foo %d", var); The need to pass in explicit __FILE__/__LINE__ is there probably because the function predates widespread and portable variadic macros availability. We can use variadic macros nowadays, and in fact, we already use them in several places, including the related gdb_assert_not_reached. So this patch renames the internal_error function to something else, and then reimplements internal_error as a variadic macro that expands __FILE__/__LINE__ itself. The result is that we now should call internal_error like so: internal_error ("foo %d", var); Likewise for internal_warning. The patch adjusts all calls sites. 99% of the adjustments were done with a perl/sed script. The non-mechanical changes are in gdbsupport/errors.h, gdbsupport/gdb_assert.h, and gdb/gdbarch.py. Approved-By: Simon Marchi <simon.marchi@efficios.com> Change-Id: Ia6f372c11550ca876829e8fd85048f4502bdcf06
2022-10-10Change GDB to use frame_info_ptrTom Tromey1-5/+5
This changes GDB to use frame_info_ptr instead of frame_info * The substitution was done with multiple sequential `sed` commands: sed 's/^struct frame_info;/class frame_info_ptr;/' sed 's/struct frame_info \*/frame_info_ptr /g' - which left some issues in a few files, that were manually fixed. sed 's/\<frame_info \*/frame_info_ptr /g' sed 's/frame_info_ptr $/frame_info_ptr/g' - used to remove whitespace problems. The changed files were then manually checked and some 'sed' changes undone, some constructors and some gets were added, according to what made sense, and what Tromey originally did Co-Authored-By: Bruno Larsen <blarsen@redhat.com> Approved-by: Tom Tomey <tom@tromey.com>
2022-10-03Improve GDB's baseclass detection with typedefsBruno Larsen1-3/+1
When a class inherits from a typedef'd baseclass, GDB may be unable to find the baseclass if the user is not using the typedef'd name, as is tested on gdb.cp/virtbase2.exp; the reason that test case is working under gcc is that the dwarf generated by gcc links the class to the original definition of the baseclass, not to the typedef. If the inheritance is linked to the typedef, such as how clang does it, gdb.cp/virtbase2.exp starts failing. This can also be seen in gdb.cp/impl-this.exp, when attempting to print D::Bint::i, and GDB not being able to find the baseclass Bint. This happens because searching for baseclasses only uses the macro TYPE_BASECLASS_NAME, which returns the typedef'd name. However, we can't switch that macro to checking for typedefs, otherwise we wouldn't be able to find the typedef'd name anymore. This is fixed by searching for members or baseclasses by name, we check both the saved name and the name after checking for typedefs. This also fixes said long-standing bug in gdb.cp/impl-this.exp when the compiler adds information about typedefs in the debuginfo.
2022-10-02gdb: update now gdbarch_register_name doesn't return nullptrAndrew Burgess1-1/+1
After the previous few commit, gdbarch_register_name no longer returns nullptr. This commit audits all the calls to gdbarch_register_name and removes any code that checks the result against nullptr. There should be no visible change after this commit.
2022-09-21gdb: remove TYPE_LENGTHSimon Marchi1-26/+26
Remove the macro, replace all uses with calls to type::length. Change-Id: Ib9bdc954576860b21190886534c99103d6a47afb
2022-09-21gdb: remove TYPE_TARGET_TYPESimon Marchi1-33/+33
Remove the macro, replace all uses by calls to type::target_type. Change-Id: Ie51d3e1e22f94130176d6abd723255282bb6d1ed
2022-04-20Replace symbol_objfile with symbol::objfileTom Tromey1-1/+1
This turns symbol_objfile into a method on symbol.
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