The nm utility supports -l for using debug information to obtain file and line information for each symbol, if available.
We have a tool that consumes this information and displays it.
This identified a problem with the 'nm' utility.
When a source is compiled with -O2, functions can be inlined. The compiler also produces an uninlined copy of the function, normally for linking to other object files.
In the case of DWARF2 debug information, the compiler generates debug information to describe a function. If that function is inlined, the compiler then references that debug information from the inlined and uninlined copies of the routine through the use of the DW_AT_abstract_origin reference.
When nm is used on such a file, it is not able to find file and line information because that information is present in the common debug information and not at each actual implementation of the function.
The 'nm' utility only retrieves the name of the function from the abstract origin debug information and no more.
What I am proposing is to modify the find_abstract_instance_name() function (which I renamed to find_abstract_instance() ) to return the name of the function as well as any file and line information. The routine is already parsing all of the debug information in the abstract instance, so it is easy to pick up the file and line information at that time. If, for some reason, the file and line information is not present, the routine behaves as before.
For example, if I have a simple test case:
int foo(int j)
{
if (j < 15)
j += j << 2;
else
j += j << 6;
return j;
}
int main (int argc,char **argv)
{
int i = argc;
i += foo(i);
return i;
}
If that test case is compiled with -O2 and then 'nm -l' reads that executable, it currently produces this symbol output (ignoring a lot of library symbols):
8048400 T foo
080482e0 T main /scratch/pcarroll/its254/test/mytest.c:12
If I modify 'nm' to return file and line information for abstract instances, it produces the following output:
08048400 T foo /scratch/pcarroll/its254/test/mytest.c:1
080482e0 T main /scratch/pcarroll/its254/test/mytest.c:12
--------------------------------------------------------------------------
bfd * bfd/dwarf2.c (find_abstract_name): Modified to return file and
line information in addition to name, if they can be found.
Like the PR22230 fix, we can allocate a buffer with an extra byte
rather than letting bfd_simple_get_relocated_section_contents malloc
and return a buffer. Much better than allocating another buffer
afterwards.
PR 22047
* dwarf2.c (read_section): Allocate buffer with extra byte for
bfd_simple_get_relocated_section_contents rather than copying
afterwards.
Using read_attribute_value accomplishes two things: It checks for
unexpected formats, and ensures the buffer pointer always increments.
PR 22210
* dwarf2.c (read_formatted_entries): Use read_attribute_value to
read data.
This patch adds bounds checking for DW_FORM_ref_addr die refs, and
calculates them relative to the first .debug_info section. See the
big comment for why calculating relative to the current .debug_info
section was wrong for relocatable object files.
PR 22209
* dwarf2.c (struct comp_unit): Delete sec_info_ptr field.
(find_abstract_instance_name): Calculate DW_FORM_ref_addr relative
to stash->info_ptr_memory, and check die_ref is within that memory.
Set info_ptr_end correctly when another CU is refd. Check die_ref
for DW_FORM_ref4 etc. is within CU.
The PR22200 fuzzer testcase found one way to put NULLs into .debug_line
file tables. PR22205 finds another. This patch gives up on trying to
prevent NULL files in the file table and instead just copes with them.
Arguably, this is better than giving up and showing no info from
.debug_line. I've also fixed a case where the fairly recent DWARF5
support in handling broken DWARG could result in uninitialized memory
reads, and made a small tidy.
PR 22205
* dwarf2.c (concat_filename): Return "<unknown>" on NULL filename.
(read_formatted_entries): Init "fe".
(decode_line_info <DW_LNE_define_file>): Use line_info_add_file_name.
DW_AT_name ought to always have a string value.
PR 22201
* dwarf2.c (scan_unit_for_symbols): Ignore DW_AT_name unless it
has string form.
(parse_comp_unit): Likewise.
table->sequences is a linked list before it is replaced by a bfd_alloc
array in sort_line_sequences.
PR 22191
* dwarf2.c (decode_line_info): Properly free line sequences on error.
This patch prevents the simple case of infinite recursion in
find_abstract_instance_name by ensuring that the attributes being
processed are not the same as the previous call.
The patch also does a little cleanup, and leaves in place some changes
to the nested_funcs array that I made when I wrongly thought looping
might occur in scan_unit_for_symbols.
PR 22187
* dwarf2.c (find_abstract_instance_name): Add orig_info_ptr and
pname param. Return status. Make name const. Don't abort,
return an error. Formatting. Exit if current info_ptr matches
orig_info_ptr. Update callers.
(scan_unit_for_symbols): Start at nesting_level of zero. Make
nested_funcs an array of structs for extensibility. Formatting.
The .debug_line header length field doesn't include the length field
itself, ie. it's the size of the rest of .debug_line.
PR 22169
* dwarf2.c (decode_line_info): Correct .debug_line unit_length check.
Fix GCC 4.2 warnings like:
cc1: warnings being treated as errors
binutils-gdb/bfd/dwarf2.c:1844: warning: declaration of ‘time’ shadows a global declaration
/usr/include/time.h:187: warning: shadowed declaration is here
binutils-gdb/bfd/dwarf2.c: In function ‘line_info_add_file_name’:
binutils-gdb/bfd/dwarf2.c:1854: warning: declaration of ‘time’ shadows a global declaration
/usr/include/time.h:187: warning: shadowed declaration is here
bfd/
* dwarf2.c (line_info_add_include_dir_stub): Replace time with
xtime.
(line_info_add_file_name): Likewise.
(decode_line_info): Likewise.
binutils/
* dwarf.c (display_debug_names): Replace index with xindex.
PR binutils/18025
* coff-bfd.h (struct coff_section_data): Add new fields:
saved_bias and bias.
* coffgen.c (coff_find_nearest_line_with_names): Cache the bias
computed for PE binaries.
* dwarf2.c (scan_unit_for_symbols): Only warn once about each
missing abbrev.
Give these bfd-internal symbols with external linkage a _bfd_ prefix
to avoid collisions in the global symbol namespace.
bfd/ChangeLog:
2017-02-17 Pedro Alves <palves@redhat.com>
* bfdio.c (real_ftell): Rename to ...
(_bfd_real_ftell): ... this.
(real_fseek): Rename to ...
(_bfd_real_fseek): ... this.
(real_fopen): Rename to ...
(_bfd_real_fopen): ... this.
* libbfd-in.h (real_ftell): Rename to ...
(_bfd_real_ftell): ... this.
(real_fseek): Rename to ...
(_bfd_real_fseek): ... this.
(real_fopen): Rename to ...
(_bfd_real_fopen): ... this.
* cache.c, dwarf2.c, opncls.c: Adjust all callers.
* libbfd.h: Regenerate.
Give these bfd-internal symbols with external linkage a _bfd_ prefix
to avoid collisions in the global symbol namespace.
bfd/ChangeLog:
2017-02-17 Pedro Alves <palves@redhat.com>
* dwarf2.c, elf-attrs.c, elf32-nds32.c: Adjust all callers.
* libbfd.c (read_unsigned_leb128): Rename to ...
(_bfd_read_unsigned_leb128): ... this.
(read_signed_leb128): Rename to ...
(_bfd_read_signed_leb128): ... this.
(safe_read_leb128): Rename to ...
(_bfd_safe_read_leb128): ... this.
* libbfd-in.h (read_unsigned_leb128): Rename to ...
(_bfd_read_unsigned_leb128): ... this.
(read_signed_leb128): Rename to ...
(_bfd_read_signed_leb128): ... this.
(safe_read_leb128): Rename to ...
(_bfd_safe_read_leb128): ... this.
* libbfd.h: Renegerate.
When looking up file and line information (used from the linker to
report error messages) if no symbol is passed in, then use the symbol
list to look for a matching symbol.
If a matching symbol is found then use this to look up the file / line
information.
This should improve errors when looking up file / line information for
data sections. Hopefully we should find a matching data symbol, which
should, in turn (we hope) match a DW_TAG_variable in the DWARF, this
should allow us to give accurate file / line errors for data symbols.
As the hope is to find a matching DW_TAG_variable in the DWARF then we
ignore section symbols, and prefer global symbols to locals.
bfd/ChangeLog:
* dwarf2.c (_bfd_dwarf2_find_nearest_line): Perform symbol lookup
before trying to fine matching file and line information.
ld/ChangeLog:
* testsuite/ld-elf/shared.exp: Update expected results.
* testsuite/ld-elf/dwarf2.err: Likewise
When parsing DWARF data in order to report file/line type error messages
we perform section placement to make section addresses unique within
relocatable object files.
Currently, if we reuse previously loaded (and cached) dwarf data then we
neglect to perform section placement, the result is that the section
addresses will not be unique, and we might, incorrectly associate an
address with the wrong debug information, and so report an incorrect
file and line number.
Further we neglect to check that that bfd for which we are looking up
debug information is actually the bfd for which the previous debug
information was loaded, it is possible that we will reuse previously
loaded debug information for a different bfd.
And finally, due to following of gnu_debuglink links in one bfd to
another, the process of checking that the cached debug information is
valid requires us to track the original bfd in the cached debug
information. The original debug information here is either the bfd that
we're interested in, not the bfd we finally load the debug information
from.
bfd/ChangeLog:
* dwarf2.c (struct dwarf2_debug): Add orig_bfd member.
(_bfd_dwarf2_slurp_debug_info): If stashed debug information does
not match current bfd, then reload debug information. Record bfd
we're loading debug info for in the stash. If we have debug
informatin in the cache then perform section placement before
returning.
ld/ChangeLog:
* testsuite/ld-elf/dwarf.exp (build_tests): Add new tests.
* testsuite/ld-elf/dwarf2.err: New file.
* testsuite/ld-elf/dwarf2a.c: New file.
* testsuite/ld-elf/dwarf2b.c: New file.
* testsuite/ld-elf/dwarf3.c: New file.
* testsuite/ld-elf/dwarf3.err: New file.
PR binutils/20876
bfd * opncls.c (find_separate_debug_file): Add include_dirs
parameter. Only include the directory part of the bfd's filename
in search paths if include_dirs is true. Add a couple of extra
locations for looking for debug files.
( bfd_follow_gnu_debuglink): Update invocation of
find_separate_debug_file.
(bfd_follow_gnu_debugaltlink): Likewise.
(get_build_id): New function: Finds the build-id of the given bfd.
(get_build_id_name): New function: Computes the name of the
separate debug info file for a bfd, based upon its build-id.
(check_build_id_file): New function: Checks to see if a separate
debug info file exists at the given location, and that its
build-id matches that of the original bfd.
(bfd_follow_build_id_debuglink): New function: Finds a separate
debug info file for a given bfd by using the build-id method.
* dwarf2.c (_bfd_dwarf2_slurp_debug_info): Try using the build-id
method of locating a separate debug info file before using the
debuglink method.
* bfd-in2.h: Regenerate.
binutils * NEWS: Mention the new feature.
* testsuite/binutils-all/objdump.exp (test_build_id_debuglink):
New proc to test the location of separate debug info files using
the build-id method.
bfd * dwarf2.c (lookup_address_in_function_table): Return early if
there are no functions in the given comp unit, or if the high
address of the last function in the comp unit is less than the
desired address.
binutils * objdump.c (display_file): Add new parameter 'last_file'. If
last_file is true, do not call bfd_close at the end of the
function.
(main): Set the value of the last_file parameter when calling
display_file.
Fix a commit 089e3718bd ("Greatly improve the speed if looking up
DWARF line number information.") build regression:
cc1: warnings being treated as errors
.../bfd/dwarf2.c: In function 'build_line_info_table':
.../bfd/dwarf2.c:1614: warning: declaration of 'index' shadows a global declaration
/usr/include/string.h:304: warning: shadowed declaration is here
.../bfd/dwarf2.c: In function 'build_lookup_funcinfo_table':
.../bfd/dwarf2.c:2262: warning: declaration of 'index' shadows a global declaration
/usr/include/string.h:304: warning: shadowed declaration is here
make[4]: *** [dwarf2.lo] Error 1
in a way following commit 91d6fa6a03 ("Add -Wshadow to the gcc command
line options used when compiling the binutils.").
bfd/
* dwarf2.c (build_line_info_table): Rename `index' local
variable to `line_index'.
(build_lookup_funcinfo_table): Rename `index' local variable to
`func_index'.
Fix build breakage introduced by commit 089e3718bd ("Greatly improve
the speed if looking up DWARF line number information."):
- bfd_boolean is_linkage;
- const char *name;
- struct arange arange;
+ int line;
+ int tag;
+ bfd boolean is_linkage;
bfd/ChangeLog:
2016-11-08 Pedro Alves <palves@redhat.com>
* dwarf2.c (struct funcinfo) <is_linkage>: Type is bfd_boolean,
not "bfd boolean".
* dwarf2.c (comp_unit): Add new fields 'lookup_funcinfo_table' and
'number_of_functions' to keep lookup table and number of entries in
the table.
(line_sequence): Add new fields 'line_info_lookup' and 'num_lines'
to keep lookup table and number of entries in the table.
(lookup_funcinfo): New structure for lookup table for function
references.
(build_line_info_table): New function to create and build the lookup
table for line information.
(lookup_address_in_line_info_table): Use the lookup table instead of
traverse a linked list.
(compare_lookup_funcinfos): New compare fuction used in sorting of
lookup table for function references.
(build_lookup_funcinfo_table): New function to create, build and
sort the lookup table for functions references.
(lookup_address_in_function_table): Use the table instead of
traverse a linked list.
(_bfd_dwarf2_cleanup_debug_info): Free memory from function references
lookup table.
PR 19872
bfd * dwarf2.c (parse_comp_unit): Skip warning about unrecognised
version number if the version is zero.
bin * dwarf.c (display_debug_aranges): Skip warning about unrecognised
version number if the version is zero.
We should set BFD_DECOMPRESS to decompress debug sections when reading in
DWARF debug sections.
bfd/
PR binutils/19523
* dwarf2.c (_bfd_dwarf2_slurp_debug_info): Set BFD_DECOMPRESS to
decompress debug sections.
binutils/
PR binutils/19523
* Makefile.am (check-DEJAGNU): Pass CC and CC_FOR_BUILD to
runtest.
* Makefile.in: Regenerated.
* testsuite/binutils-all/compress.exp (test_gnu_debuglink): New
proc.
Run test_gnu_debuglink for native ELF build.
In this case the inlined function doesn't have DW_AT_linkage_name in
.debug_info, but the language is C++ so find_nearest_line goes looking
in the symbol table. Since the function is inlined the enclosing
non-inline function symbol is returned from _bfd_elf_find_function,
which is wrong. This patch only uses a symbol if its address matches.
PR binutils/19315
* dwarf2.c (_bfd_elf_find_function): Return symbol matched.
(_bfd_dwarf2_find_nearest_line): Check symbol returned above
against dwarf range.
* elf-bfd.h (_bfd_elf_find_function): Update prototype.
This patch fixes all occurences of left-shifting negative constants in C code
which is undefined by the C standard.
bfd/ChangeLog:
* elf64-ppc.c (ppc64_elf_size_stubs, ppc64_elf_build_stubs): Fix left
shift of negative value.
* libbfd.c (safe_read_leb128): Likewise.
* dwarf2.c (place_sections): Likewise.
* bfd-in.h (align_power): Likewise.
* bfd-in2.h (align_power): Likewise.
PR binutils/18025
* coffgen.c (coff_find_nearest_line_with_names): If the dwarf2
lookup fails, check for an address bias in the dwarf info, and if
one exists, retry the lookup with the biased value.
* dwarf2.c (_bfd_dwarf2_find_symbol_bias): New function.
Determines if a bias exists bewteen the addresses of functions
based on DWARF information vs symbol table information.
* libbfd-in.h (_bfd_dwarf2_find_symbol_bias): Prototype.
* libbfd.h: Regenerate.
PR binutils/17512
* dwarf.c (read_1_byte, read_1_signed_byte, read_2_bytes)
(read_4_bytes, read_8_bytes, read_n_bytes, read_string)
(read_indirect_string, read_alt_indirect_string)
(read_alt_indirect_ref, read_address, read_abbrevs)
(read_attribute_value, read_attribute, decode_line_info)
(find_abstract_instance_name, read_rangelist)
(scan_unit_for_symbols, parse_comp_unit)
(_bfd_dwarf2_find_nearest_line): Harden DWARF reading code. Pass
end pointers to reading functions and check for offsets taking
pointers out of range. Replace calls to read_*_leb128 with calls
to safe_read_leb128.
(* elf64-ppc.c (opd_entry_value): Add a check for an overlarge
offset.
* syms.c (_bfd_stab_section_find_nearest_line): Add checks for
computed file_name address being before the start of the string
table.
PR binutils/17512
* addr2line.c (slurp_symtab): If the symcount is zero, free the
symbol table pointer.
* dwarf2.c (concat_filename): Check for an empty directory table.
(scan_unit_for_symbols): Check for reading off the end of the
unit.
(parse_comp_unit): Check for a DW_AT_comp_dir attribute with a
non-string form.
* elf64-ppc.c (opd_entry_value): Fail if there are no relocs
available.
