GDB is able to cache memory accesses requested in target_read_code,
so target_read_code is more efficient than general target_read_memory.
This patch uses target_read_code and its variants to read target
memory in the functions related to i386_skip_prologue. It improves
the performance when doing 'b foo' (foo is a function) in remote
debugging.
Nowadays, when we set a breakpoint on function f1, GDB will fetch the
code in f1 to determine the start of the function body (say skip the
prologue), it requests read from target many times. With this patch
applied, the number of RSP 'm' packets are reduced.
gdb:
2013-12-10 Yao Qi <yao@codesourcery.com>
* corefile.c (read_code): New function.
(read_code_integer): New function.
(read_code_unsigned_integer): New function.
* gdbcore.h (read_code): Declare.
(read_code_integer): Declare.
(read_code_unsigned_integer): Declare.
* i386-tdep.c (i386_follow_jump): Call target_read_code instead
of target_read_memory. Call read_code_unsigned_integer instead
of read_memory_unsigned_integer.
(i386_analyze_struct_return): Likewise.
(i386_skip_probe): Likewise.
(i386_analyze_stack_align): Likewise.
(i386_match_pattern): Likewise.
(i386_skip_noop): Likewise.
(i386_analyze_frame_setup): Likewise.
(i386_analyze_register_saves): Likewise.
(i386_skip_prologue): Likewise.
(i386_skip_main_prologue): Likewise.
(i386_frame_cache_1): Likewise.
This helps with the following issue: Given an Ada program defining
a global variable:
package Pck is
Watch : Integer := 1974;
end Pck;
When printing the address of this variable, GDB also tries to print
the associated symbol name:
(gdb) p watch'address
$1 = (access integer) 0x6139d8 <pck__watch>
^^
||
The problem is that GDB prints the variable's linkage name, instead
of its natural name. This is because the language of the associated
minimal symbol never really gets set.
This patch adds handling for Ada symbols in symbol_find_demangled_name.
After this patch, we now get:
(gdb) p watch'address
$1 = (access integer) 0x6139d8 <pck.watch>
^
|
gdb/ChangeLog:
* symtab.c (symbol_find_demangled_name): Add handling of
Ada symbols.
gdb/testsuite/ChangeLog:
* gdb.ada/int_deref.exp: Add test verifying that we print
the decoded symbol name when printing the address of Ada
symbols.
This adds "exec-run-start-option" in the output of the -list-features
commands, allowing front-ends to easily determine whether -exec-run
supports the --start option.
gdb/ChangeLog:
* mi/mi-main.c (mi_cmd_list_features): add "exec-run-start-option".
* NEWS: Expand the entry documenting the new -exec-run --start
option to mention the corresponding new entry in the output of
"-list-features".
gdb/doc/ChangeLog:
* gdb.texinfo (GDB/MI Miscellaneous Commands): Document the new
"exec-run-start-option" entry in the output of the "-list-features"
command.
gdb/testsuite/ChangeLog:
* gdb.mi/mi-start.exp: Add test verifying that -list-features
contains "exec-run-start-option".
We observed on Windows 2012 that we were unable to unwind past
exception handlers. For instance, with any Ada program raising
an exception that does not get handled:
% gnatmake -g a -bargs -shared
% gdb a
(gdb) start
(gdb) catch exception unhandled
Catchpoint 2: unhandled Ada exceptions
(gdb) c
Catchpoint 2, unhandled CONSTRAINT_ERROR at <__gnat_unhandled_exception> (
e=0x645ff820 <constraint_error>) at s-excdeb.adb:53
53 s-excdeb.adb: No such file or directory.
At this point, we can already see that something went wrong, since
the frame selected by the debugger corresponds to a runtime function
rather than the function in the user code that caused the exception
to be raised (in our case procedure A).
This is further confirmed by the fact that we are unable to unwind
all the way to procedure A:
(gdb) bt
#0 <__gnat_unhandled_exception> (e=0x645ff820 <constraint_error>)
at s-excdeb.adb:53
#1 0x000000006444e9a3 in <__gnat_notify_unhandled_exception> (excep=0x284d2
+0)
at a-exextr.adb:144
#2 0x00000000645f106a in __gnat_personality_imp ()
from C:\[...]\libgnat-7.3.dll
#3 0x000000006144d1b7 in _GCC_specific_handler (ms_exc=0x242fab0,
this_frame=0x242fe60, ms_orig_context=0x242f5c0, ms_disp=0x242ef70,
gcc_per=0x645f0960 <__gnat_personality_imp>)
at ../../../src/libgcc/unwind-seh.c:289
#4 0x00000000645f1211 in __gnat_personality_seh0 ()
from C:\[...]\libgnat-7.3.dll
#5 0x000007fad3879f4d in ?? ()
Backtrace stopped: previous frame inner to this frame (corrupt stack?)
It turns out that the unwinder has been doing its job flawlessly
up until frame #5. The address in frame #5 is correct, but GDB
is not able to associate it with any symbol or unwind record.
And this is because this address is inside ntdll.dll, and when
we received the LOAD_DLL_DEBUG_EVENT for that DLL, the system
was not able to tell us the name of the library, thus causing us
to silently ignoring the event. Because GDB does not know about
ntdll.dll, it is unable to access the unwind information from it.
And because the function at that address does not use a frame
pointer, the unwinding becomes impossible.
This patch helps recovering ntdll.dll at the end of the "run/attach"
phase, simply by trying to locate that specific DLL again.
In terms of our medium to long term planning, it seems to me that
we should be able to simplify the code by ignoring LOAD_DLL_DEBUG_EVENT
during the startup phase, and modify windows_ensure_ntdll_loaded
to then detect and report all shared libraries after we've finished
inferior creation. But for a change just before 7.7 branch creation,
I thought it was safest to just handle ntdll.dll specifically. This
is less intrusive, and ntdll is the only DLL affected by the problem
I know so far.
gdb/ChangeLog:
* windows-nat.c (handle_load_dll): Add comments.
(windows_ensure_ntdll_loaded): New function.
(do_initial_windows_stuff): Use windows_ensure_ntdll_loaded.
Add FIXME comment.
We added a new proc gdb_produce_source recently, and it can be used
more widely in lib/gdb.exp to generate source file.
gdb/testsuite:
2013-12-08 Yao Qi <yao@codesourcery.com>
* lib/gdb.exp (support_complex_tests): Use gdb_produce_source.
(is_elf_target, is_ilp32_target, is_ilp64_target): Likewise.
(is_64_target, is_amd64_regs_target): Likewise.
(skip_altivec_tests, skip_vsx_tests, skip_btrace_tests): Likewise.
libx.so refers to some_sym, liby.so provides some_sym@some_version
wasn't seen as satisfying the reference.
* elf64-ppc.c (_bfd_elf_add_default_symbol): Set dynamic_def
and ref_dynamic_nonweak when chaining together indirect
symbols.
Hi,
I see such warning below on one compiler I am using.
cc1: warnings being treated as errors
../../workspace/gdb/stack.c: In function 'frame_info':
../../workspace/gdb/stack.c:1519:20: error: 'caller_pc' may be used uninitialized in this function
Go through the gdb-patches archives and find the "canonical" way to
fix this warning is to initialize the variable.
gdb:
2013-12-08 Yao Qi <yao@codesourcery.com>
* stack.c (frame_info): Initialize variable caller_pc.
I meant for this script to be +x, but missed when doing the initial CVS
commit. It wasn't possible to fix w/CVS, but it is w/git, so do it.
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2012-12-03 Mike Frysinger <vapier@gentoo.org>
* run-tests.sh: Add +x file mode.
These files are source files and have no business being +x. We couldn't
easily fix it in CVS (you need login+write access to the raw rcs files),
but we can fix this w/git.
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
These scripts use /bin/ksh, but they're dirt simple and can be used with
/bin/sh, so just change the shebang.
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Doing "info frame" in the outermost frame, when that was indicated by
the next frame saying the unwound PC is undefined/not saved, results
in error and incomplete output:
(gdb) bt
#0 thread_function0 (arg=0x0) at threads.c:63
#1 0x00000034cf407d14 in start_thread (arg=0x7ffff7fcb700) at pthread_create.c:309
#2 0x000000323d4f168d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:115
(gdb) frame 2
#2 0x000000323d4f168d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:115
115 call *%rax
(gdb) info frame
Stack level 2, frame at 0x0:
rip = 0x323d4f168d in clone (../sysdeps/unix/sysv/linux/x86_64/clone.S:115); saved rip Register 16 was not saved
(gdb)
Not saved register values are treated as optimized out values
internally throughout. stack.c:frame_info is handing unvailable
values, but not optimized out ones. The patch deletes the
frame_unwind_caller_pc_if_available wrapper function and instead lets
errors propagate to frame_info (it's only user).
As frame_unwind_pc now needs to be able to handle and cache two
different error scenarios, the prev_pc.p variable is replaced with an
enumeration.
(FWIW, I looked into making gdbarch_unwind_pc or a variant return
struct value's instead, but it results in lots of boxing and unboxing
for no real gain -- e.g., the mips and arm implementations need to do
computation on the unboxed PC value. Might as well throw an error on
first attempt to get at invalid contents.)
After the patch, we get:
(gdb) info frame
Stack level 2, frame at 0x0:
rip = 0x323d4f168d in clone (../sysdeps/unix/sysv/linux/x86_64/clone.S:115); saved rip = <not saved>
Outermost frame: outermost
caller of frame at 0x7ffff7fcafc0
source language asm.
Arglist at 0x7ffff7fcafb8, args:
Locals at 0x7ffff7fcafb8, Previous frame's sp is 0x7ffff7fcafc8
(gdb)
A new test is added. It's based off dw2-reg-undefined.exp, and tweaked to
mark the return address (rip) of "stop_frame" as undefined.
Tested on x86_64 Fedora 17.
gdb/
2013-12-06 Pedro Alves <palves@redhat.com>
* frame.c (enum cached_copy_status): New enum.
(struct frame_info) <prev_pc.p>: Change type to enum
cached_copy_status.
(fprint_frame): Handle not saved and unavailable prev_pc values.
(frame_unwind_pc_if_available): Delete and merge contents into ...
(frame_unwind_pc): ... here. Handle OPTIMIZED_OUT_ERROR. Adjust
to use enum cached_copy_status.
(frame_unwind_caller_pc_if_available): Delete.
(create_new_frame): Adjust.
* frame.h (frame_unwind_caller_pc_if_available): Delete
declaration.
* stack.c (frame_info): Use frame_unwind_caller_pc instead of
frame_unwind_caller_pc_if_available, and handle
NOT_AVAILABLE_ERROR and OPTIMIZED_OUT_ERROR errors.
* valprint.c (val_print_optimized_out): Use val_print_not_saved.
(val_print_not_saved): New function.
* valprint.h (val_print_not_saved): Declare.
gdb/testsuite/
2013-12-06 Pedro Alves <palves@redhat.com>
* gdb.dwarf2/dw2-undefined-ret-addr.S: New file.
* gdb.dwarf2/dw2-undefined-ret-addr.c: New file.
* gdb.dwarf2/dw2-undefined-ret-addr.exp: New file.
In order to catch <optimized out> errors like we catch <unavailable>
errors, this adds a new OPTIMIZED_OUT_ERROR error code, and throws it
in various places.
gdb/ChangeLog
2013-12-06 Andrew Burgess <aburgess@broadcom.com>
Pedro Alves <palves@redhat.com>
* exceptions.h (errors): Add OPTIMIZED_OUT_ERROR.
* dwarf2loc.c (write_pieced_value): Throw OPTIMIZED_OUT_ERROR.
* frame.c (frame_unwind_register): Throw OPTIMIZED_OUT_ERROR.
* spu-tdep.c (spu_software_single_step): Throw
OPTIMIZED_OUT_ERROR.
* valops.c (value_assign): Throw OPTIMIZED_OUT_ERROR.
The introductory comment to free_objfile is obsolete.
This patch fixes it by removing all the obsolete bits.
2013-12-06 Tom Tromey <tromey@redhat.com>
* objfiles.c (free_objfile): Update comment.
I happened to notice that nothing uses objfile_to_front.
This patch removes it.
2013-12-06 Tom Tromey <tromey@redhat.com>
* objfiles.h (objfile_to_front): Remove.
* objfiles.c (objfile_to_front): Remove.
This removes an unnecessary declaration from minsyms.c.
2013-12-06 Tom Tromey <tromey@redhat.com>
* minsyms.c (get_symbol_leading_char): Remove unnecessary
declaration.
This improves the packing of struct partial_symtab. I noticed with
pahole that were were a couple of holes. This consolidates the holes
without, I think, affecting readability -- it just moves the "user"
field a bit earlier in the struct. This change saves a small amount
of memory.
2013-12-06 Tom Tromey <tromey@redhat.com>
* psympriv.h (struct partial_symtab) <user>: Move earlier.
This fixes a couple of old "32x64" FIXME comments by using paddress
with current_gdbarch rather than hex_string and a cast to long.
2013-12-06 Tom Tromey <tromey@redhat.com>
* cli/cli-cmds.c (edit_command): Use paddress, not hex_string.
(list_command): Likewise.
This puts the psymtab filename in the filename bcache.
This saves a small amount of memory.
2013-12-06 Tom Tromey <tromey@redhat.com>
* psymtab.c (allocate_psymtab): Put the filename in the filename
bcache.
This makes symtab::dirname const and updates one spot to avoid an
intermediate constless result.
2013-12-06 Tom Tromey <tromey@redhat.com>
* buildsym.c (end_symtab_from_static_block): Use obstack_copy0.
* symtab.h (struct symtab) <dirname>: Now const.
This makes symtab::filename const and removes a newly unnecessary
cast.
2013-12-06 Tom Tromey <tromey@redhat.com>
* symfile.c (allocate_symtab): Remove cast.
* symtab.h (struct symtab) <filename>: Now const.
While looking into the probe API, it seemed to me that there were a
number of methods in sym_probe_fns that were not needed. This patch
removes them.
Specifically, it seems to me that sym_probe_fns ought to be concerned
with the API for constructing the probes. Any method relating to some
aspect of an individual probe can be handled via the probe's own
vtable. That is, the double indirection here doesn't seem useful --
it certainly isn't in fact used, but also I couldn't think of a
potential use.
2013-12-06 Tom Tromey <tromey@redhat.com>
* break-catch-throw.c (fetch_probe_arguments): Use
get_probe_argument_count and evaluate_probe_argument.
* elfread.c (elf_get_probe_argument_count)
(elf_can_evaluate_probe_arguments, elf_evaluate_probe_argument)
(elf_compile_to_ax): Remove.
(elf_probe_fns): Update.
* probe.c (get_probe_argument_count, can_evaluate_probe_arguments)
(evaluate_probe_argument): Call method on probe, not via sym
functions.
* stap-probe.c (compute_probe_arg): Use get_probe_argument_count,
evaluate_probe_argument.
(compile_probe_arg): Use get_probe_argument_count. Call method on
probe, not via sym functions.
* symfile-debug.c (debug_sym_get_probe_argument_count)
(debug_can_evaluate_probe_arguments)
(debug_sym_evaluate_probe_argument, debug_sym_compile_to_ax):
Remove.
(debug_sym_probe_fns): Remove.
* symfile.h (struct sym_probe_fns) <sym_get_probe_argument_count,
can_evaluate_probe_arguments, sym_evaluate_probe_argument,
sym_compile_to_ax>: Remove fields.
In some languages, e.g. fortran, arrays start with index 1
instead 0. This patch changes the MI library to support testing
varobj children of fortran arrays.
2013-11-21 Keven Boell <keven.boell@intel.com>
testsuite/
* lib/mi-support.exp (mi_list_varobj_children_range): Add
call to mi_list_array_varobj_children_with_index.
(mi_list_array_varobj_children_with_index): New function.
Add parameter to specify array start.
* p-exp.y (exp : field_exp name): Do not call mark_struct_expression.
(exp : field_exp name COMPLETE): New rule.
(exp : SIZEOF): Set correct current_type.
(last_was_structop): Remove static variable.
(yylex): Remove saw_structop local variable.
Adapt code to removal of variables above.
With a simple Ada program where I have 3 functions, one just calling
the next, the backtrace is currently broken when GDB is compiled
at -O2:
#0 hello.first () at hello.adb:5
#1 0x0000000100001475 in hello.second () at hello.adb:10
Backtrace stopped: previous frame inner to this frame (corrupt stack?)
It turns out that a recent patch deleted the assignment of variable
this_id, making it an unitialized variable:
* frame-unwind.c (default_frame_unwind_stop_reason): Return
UNWIND_OUTERMOST if the frame's ID is outer_frame_id.
* frame.c (get_prev_frame_1): Remove outer_frame_id check.
The hunk in question starts with:
- /* Check that this frame is not the outermost. If it is, don't try
- to unwind to the prev frame. */
- this_id = get_frame_id (this_frame);
- if (frame_id_eq (this_id, outer_frame_id))
(the code was removed as redundant - but removing the assignment
was in fact not intentional).
There is no other code in this function that sets the variable.
Instead of re-adding the statement in the lone section where it is
actually used, I inlined it, and then got rid of the variable
altogether. This way, and until we start needing this frame ID
in another location within that function, we dont' have to worry
about the variable's validity/lifetime.
gdb/ChangeLog:
* frame.c (get_prev_frame_1): Delete variable "this_id".
Replace its use by a call to get_frame_id.
We've observed in Windows 2012 that ntdll.dll contains some unwind
records with the version field set to 2. This patch adjusts the
decoder to accept records flagged with this version as well.
Version 2 appears to still be largely undocumented at this stage.
However, apart from a mysterious opcode 6, everything else still
seems to remain the same. So this patch also changes the decoder
to ignore those opcodes; before this change, the debugger would
silently stop the decoding, and let the frame unwinder make do
with what it the decoder managed to decode up to that point.
It's unclear at this point what we're losing by not being able to
decode that opcode. But the information does not appear to be critical,
at least as far as call unwinding is concerned.
gdb/ChangeLog:
(from Tristan Gingold <gingold@adacore.com>)
(from Joel Brobecker <brobecker@adacore.com>)
* amd64-windows-tdep.c (amd64_windows_frame_decode_insns):
Accept version 2. Ignore operations using opcode 6.
I wanted to find the docs for "catch load" the other day, and I found
out that this isn't in the index. It seems to me that each command
ought to be in the index for quick reference like this, so this patch
adds an @kindex (chosen because it seems to be what the rest of the
manual does) for each "catch" subcommand.
2013-12-03 Tom Tromey <tromey@redhat.com>
* gdb.texinfo (Set Catchpoints): Add @kindex for each command
documented here.
