This applies the second part of GDB's End of Year Procedure, which
updates the copyright year range in all of GDB's files.
gdb/ChangeLog:
Update copyright year range in all GDB files.
break-asm-file.exp has some manually written dwarf to create some line
number entries like this,
[0x0000013d] Extended opcode 2: set Address to 0x40053f
[0x00000144] Advance Line by 4 to 7
[0x00000146] Copy
[0x00000147] Extended opcode 2: set Address to 0x400541
[0x0000014e] Advance Line by 1 to 8
[0x00000150] Copy
[0x00000151] Extended opcode 2: set Address to 0x400547
[0x00000158] Extended opcode 1: End of Sequence
0x40053f is the start address of function func, and is mapped to line
7. 0x400541 is within function func, and is mapped to line 8.
(gdb) disassemble /r 0x40053f,+8
Dump of assembler code from 0x40053f to 0x400547:
0x000000000040053f <func+0>: 00 00 add %al,(%rax)
0x0000000000400541 <func+2>: 00 00 add %al,(%rax)
0x0000000000400543 <func+4>: 00 00 add %al,(%rax)
0x0000000000400545 <func+6>: 00 00 add %al,(%rax)
in the following test,
(gdb) break a/break-asm-file0.s:func
Breakpoint 1 at 0x40053f: file a/break-asm-file0.s, line 7.
As we can see, breakpoint is set at the start address of function func
on x86, which means no prologue is skipped. On other targets, such as
arm and aarch64, breakpoint is set at the address *after* the start
address, which is mapped to line 8. Then test fails.
In fact, it is lucky this test doesn't fail on x86 and x86_64, whose
gdbarch method skip_prologue doesn't reply on skip_prologue_using_sal
if producer isn't clang.
if (find_pc_partial_function (start_pc, NULL, &func_addr, NULL))
{
CORE_ADDR post_prologue_pc
= skip_prologue_using_sal (gdbarch, func_addr);
struct compunit_symtab *cust = find_pc_compunit_symtab (func_addr);
/* Clang always emits a line note before the prologue and another
one after. We trust clang to emit usable line notes. */
if (post_prologue_pc
&& (cust != NULL
&& COMPUNIT_PRODUCER (cust) != NULL
&& startswith (COMPUNIT_PRODUCER (cust), "clang ")))
return max (start_pc, post_prologue_pc);
}
so it doesn't return and go further to prologue analyser. Since ".int 0"
isn't an instruction of prologue, nothing is skipped, starting address
is used, and test passes.
however, on targets which don't have such producer checking, the first
line number entry is skipped, and skip_prologue_using_sal returns sal
represents the second line number entry.
The idea of this patch is to force GDB stop at somewhere which is stilled
mapped to line 7 after skipping prologue. I choose to add a new line
number entry for the following instruction but mapped to the same line (7),
because I see the comments in dwarf2read.c,
... fact that two consecutive
line number entries for the same line is a heuristic used by gcc
to denote the end of the prologue.
then the line table becomes:
[0x000000d4] Extended opcode 2: set Address to 0x400529
[0x000000db] Advance Line by 4 to 7
[0x000000dd] Copy
[0x000000de] Extended opcode 2: set Address to 0x40052a
[0x000000e5] Advance Line by 0 to 7
[0x000000e7] Copy
[0x000000e8] Extended opcode 2: set Address to 0x40052b
[0x000000ef] Advance Line by 1 to 8
[0x000000f1] Copy
[0x000000f2] Extended opcode 2: set Address to 0x40052c
[0x000000f9] Extended opcode 1: End of Sequence
gdb/testsuite:
2015-03-26 Yao Qi <yao.qi@linaro.org>
PR testsuite/18139
* gdb.linespec/break-asm-file0.s (func): New label .Lfunc_2.
Add a line number entry for the same line.
* gdb.linespec/break-asm-file1.s (func): New label .Lfunc_2.
Add a line number entry for the same line.
There are some hard-coded stuff in .s files, such as .int 0 and
address offset, which isn't portable. This patch is to replace
".int 0" with nop and address offset with labels.
gdb/testsuite:
2015-03-26 Yao Qi <yao.qi@linaro.org>
* gdb.linespec/break-asm-file0.s (func2): Use nop instead of
.int 0.
(func): Likewise. Add .Lfunc_1 label.
Use .Lfunc_1 label.
* gdb.linespec/break-asm-file1.s (func3): Use nop instead of
.int 0.
(func): Likewise.
Use .Lfunc_1 label.
This patch fixes a problem when trying to insert a breakpoint on
a specific symbol defined in a specific file, eg:
break foo.c:func
This currently works for files in C/C++/Ada, etc, but doesn't always
work for Asm files. Analysis of the problem showed that this related
to a limitation in gas, which does not generate debug info for functions/
symbols. Thus, we have a symtab for the file ("info sources" shows
the file), but it contains no symbols.
When find_linespec_symbols is called in linespec_parse_basic, it calls
find_function_symbols, which uses add_matching_symbols_to_info to
collect all matching symbols.
That function does [pardon any mangled formatting]:
for (ix = 0; VEC_iterate (symtab_ptr, info->file_symtabs, ix, elt); ++ix)
{
if (elt == NULL)
{
iterate_over_all_matching_symtabs (info->state, name, VAR_DOMAIN,
collect_symbols, info,
pspace, 1);
search_minsyms_for_name (info, name, pspace);
}
else if (pspace == NULL || pspace == SYMTAB_PSPACE (elt))
{
/* Program spaces that are executing startup should have
been filtered out earlier. */
gdb_assert (!SYMTAB_PSPACE (elt)->executing_startup);
set_current_program_space (SYMTAB_PSPACE (elt));
iterate_over_file_blocks (elt, name, VAR_DOMAIN,
collect_symbols, info);
}
}
This iterates over the symtabs. In the failing use case, ELT is
non-NULL (points to the symtab for the .s file), so it calls
iterate_over_file_blocks. Herein is where the problem exists: it is
assumed that if NAME exists, it must exist in the given symtab -- a
reasonable assumption for "normal" (non-asm) cases. It never searches
minimal symbols (or in the global default symtab).
This patch fixes the problem by doing so. It is important to note that
iterating over minsyms is fairly expensive, so this patch only adds
that extra search if the language is language_asm and
iterate_over_file_blocks returns no symbols.
gdb/ChangeLog:
2014-12-20 Keith Seitz <keiths@redhat.com>
Mihail-Marian Nistor <mihail.nistor@freescale.com>
PR gdb/17394
* linespec.c (struct collect_minsyms): Add new member `symtab'.
(add_minsym): Handle cases where info.symtab is non-NULL.
(search_minsyms_for_name): Add new parameter `symtab'.
Handle limiting searches to a specific symtab.
(add_matching_symtabs_to_info): Search through minimal symbols
for language_asm files for which no new symbols are found.
gdb/testsuite/ChangeLog:
2014-12-20 Mihail-Marian Nistor <mihail.nistor@freescale.com>
PR gdb/17394
* gdb.linespec/break-asm-file.c: New file.
* gdb.linespec/break-asm-file.exp: New file.
* gdb.linespec/break-asm-file0.s: New file.
* gdb.linespec/break-asm-file1.s: New file.
