Fuzzers stress the assembler in ways no sane programmer would ever do.
One x86 oss-fuzz testcase (cleaned up a litte) was:
.sect .debug_frame
call x
.long x,0
.space 1
.long 0,0
The call insn leaves the frag data corresponding to a CIE
uninitialised until later in assembly, leading to reports of
uninitialised data access in ehopt.c:check_eh_frame.
Hack around this problem by noticing an insn has been assembled in
dwarf2_emit_insn. The existing frag has_code can't be used as that
leads to alignment complaints, so add a new segment_info flag.
* subsegs.h (struct segment_info_struct): Move bss and hadone
later. Rename hadone to stab_seen. Add insn_seen bitfield.
* dwarf2dbg.c (dwarf2_emit_insn): Set insn_seen.
* ehopt.c (check_eh_frame): Disable optimisation if insn_seen.
* stabs.c (s_stab_generic): Adjust for hadone rename.
I was puzzling over how it was correct to cast what is clearly a
struct line_entry** pointer to a struct line_entry* pointer for a
few moments, and was going to write a comment but then decided we
really don't require the "next" pointer to be where it is. Replace
the assert with an inline function that does any necessary pointer
adjustments.
* dwarf2dbg.c (line_entry.next): Delete static assertion.
(line_entry_at_tail): New inline function.
(dwarf2_gen_line_info_1, dwarf2_finish): Replace casts in
set_or_check_view arguments with line_entry_at_tail.
Specifying --gdwarf-5 with a source lacking a ".file 0" directive
results in this segfault.
* dwarf2dbg.c (out_debug_str): Use files[1] if files[0] is
empty regardless of dwarf level.
Support added in commit 3417bfca67 for dwarf5 directory table 0
assumed that .file 0 was always the first debug .file directive.
That's not necessarily true.
* dwarf2dbg.c (get_directory_table_entry): Don't assume entry
1 is available after putting DW_AT_comp_dir in entry 0. Pass
pwd as file0_dirname to recursive call to avoid another
getpwd in the case file0_dirname is NULL.
Currently we allow insane file numbers that cause gas to allocate up
to 4G of memory for a file array. Trim that a little to 1G (which
still allows insane file numbers up to 33554431), and tidy function
parameter types so that we only need one file number sanity check.
* dwarf2dbg.c (assign_file_to_slot): Take a valueT file number.
Reduce max files array size.
(allocate_filename_to_slot): Take a valueT file number.
(dwarf2_directive_filename): Don't duplicate file number
sanity check here.
Adds two new external authors to etc/update-copyright.py to cover
bfd/ax_tls.m4, and adds gprofng to dirs handled automatically, then
updates copyright messages as follows:
1) Update cgen/utils.scm emitted copyrights.
2) Run "etc/update-copyright.py --this-year" with an extra external
author I haven't committed, 'Kalray SA.', to cover gas testsuite
files (which should have their copyright message removed).
3) Build with --enable-maintainer-mode --enable-cgen-maint=yes.
4) Check out */po/*.pot which we don't update frequently.
Currently, when using -gdwarf-2, gas emits a v3 .debug_line contribution.
Fix this by emitting a v2 .debug_line contribution instead.
gas/ChangeLog:
2023-01-31 Tom de Vries <tdevries@suse.de>
PR 23941
* dwarf2dbg.c (DWARF2_LINE_VERSION): Set to 2 for -gdwarf-2.
(DWARF2_LINE_OPCODE_BASE): Handle DWARF2_LINE_VERSION == 2.
(dwarf2_directive_loc): Bump dwarf_level when encountering
v3 .loc options.
(out_debug_line): Don't output v3 standard opcodes for v2.
* testsuite/gas/i386/debug1.d: Update.
* testsuite/gas/i386/dwarf2-line-1.d: Update.
* testsuite/gas/i386/dwarf2-line-4.d: Update.
There's a comment a few lines earlier saying that demand_copy_C_string
has already reported an error if it returns NULL. Given the proximity
I decided not to duplicate the comment.
* dwarf2dbg.c (dwarf2_directive_filename): Check return of
demand_copy_C_string for file.
The newer update-copyright.py fixes file encoding too, removing cr/lf
on binutils/bfdtest2.c and ld/testsuite/ld-cygwin/exe-export.exp, and
embedded cr in binutils/testsuite/binutils-all/ar.exp string match.
PR 29559
* dwarf2dbg.c (out_debug_info): Place DW_TAG_unspecified_type at
the end of the list of children, not at the start of the CU
information.
* testsuite/gas/elf/dwarf-3-func.d: Update expected output.
* testsuite/gas/elf/dwarf-5-func-global.d: Likewise.
* testsuite/gas/elf/dwarf-5-func-local.d: Likewise.
* testsuite/gas/elf/dwarf-5-func.d: Likewise.
out_inc_line_addr and relax_inc_line_addr are passed INT_MAX as
line_delta to flag end of section. This filters its way down to
size_inc_line_addr and emit_inc_line_addr. Pass line_delta on to
scale_addr_delta where it can be used to omit an unaligned opcode
error.
PR 29494
* dwarf2dbg.c (scale_addr_delta): Delete unnecessary forward decl.
Add line_delta param. Don't print error at end of section, just
round the address down.
(size_inc_line_addr, emit_inc_line_addr): Adjust calls.
PR 29517
* dwarf2dbg.c (GAS_ABBREV_COMP_UNIT): New defined constant.
(GAS_ABBREV_SUBPROG): New defined constant.
(GAS_ABBREV_NO_TYPE): New defined constant.
(out_debug_abbrev): Use the new defined constants when emitting
abbreviation numbers. Generate an abbreviation for an unspecified
type.
(out_debug_info): Use the new defined constants when referring to
abbreviations. Generate a use of the no_type abbreviation.
Reference the use when generating DIEs for functions.
* testsuite/gas/elf/dwarf-3-func.d: Update to allow for newly
extended output from the assembler.
* testsuite/gas/elf/dwarf-5-func-global.d: Likewise.
* testsuite/gas/elf/dwarf-5-func-local.d: Likewise.
* testsuite/gas/elf/dwarf-5-func.d: Likewise.
PR gas/29451
While out_debug_abbrev() properly skips such functions, out_debug_info()
mistakenly didn't. It needs to calculate the high_pc expression ahead of
time, in order to skip emitting any data for the function if the value
is zero.
The one case which would still leave a zero-size entry is when
symbol_get_obj(symp)->size ends up evaluating to zero. I hope we can
expect that to not be the case, otherwise we'd need to have a way to
post-process .debug_info contents between resolving expressions and
actually writing the data out to the file. Even then it wouldn't be
entirely obvious in which way to alter the data.
Make it a little more obvious that remap_debug_filename returns an
allocated string (that should be freed) by returning a char * rather
than const char *. Free a few missed cases in dwarf2dbg.c, and free
other memory allocated in dwarf2dbg.c. Also remove static
initialisation of variables and initialise in dwarf2_init instead,
in order to ensure gas state is saner for oss-fuzz.
* remap.c (remap_debug_filename): Remove const from return.
* as.h (remap_debug_filename): Update prototype.
* config/obj-elf.c (obj_elf_ident): Simplify free of
remap_debug_filename output.
* stabs.c (stabs_generate_asm_file): Likewise.
* dwarf2dbg.c (dirs, dirs_in_use, dirs_allocated, current): Don't
initialise statically..
(dwarf2_init): ..do so here, along with most other static vars.
(assign_file_to_slot): Don't set files_allocated until we
succeed in allocating memory.
(purge_generated_debug): Add bool param, free more stuff if true.
(dwarf2_directive_filename): Adjust purge_generated_debug call.
(process_entries): Don't free line_entry here..
(dwarf2_cleanup): ..do so here instead, new function.
(dwarf2_finish): Call dwarf2_cleanup. When chaining together
subseg line entries, unhook entries from old subseg list.
(dwarf2_directive_loc): Free remap_debug_filename string.
(out_dir_and_file_list): Likewise.
(out_debug_str): Likewise.
These were used originally to represent "# <line> <file>" constructs
inserted by (typically) compilers when pre-processing. Quite some time
ago they were replaced by .linefile though. Since the original
directives were never documented, we ought to be able to remove support
for them. As a result in a number of case function parameter aren't used
anymore and can hence be dropped.
To help tools like addr2line looking up function names, in particular
when dealing with e.g. PE/COFF binaries (linked from ELF objects), where
there's no ELF symbol table to fall back to, emit minimalistic
information for functions marked as such and having their size
specified.
Notes regarding the restriction to (pure) ELF:
- I realize this is a layering violation; I don't see how to deal with
that in a better way.
- S_GET_SIZE(), when OBJ_MAYBE_ELF is defined, looks wrong: Unlike
S_SET_SIZE() it does not check whether the hook is NULL.
- symbol_get_obj(), when OBJ_MAYBE_ELF is defined, looks unusable, as
its return type can only ever be one object format's type (and this
may then not be ELF's).
The new testcases are limited to x86 because I wanted to include the
case where function size can't be determined yet at the time Dwarf2 info
is generated. As .nops gains support by further targets, they could also
be added here then (with, as necessary, expecations suitably relaxed to
cover for insn size differences).
First of all when a table entry has a NULL filename, the two inner if()s
are better done the other way around: The 2nd doesn't depend on what the
first does. This then renders redundant half of the conditions of the
other if() and clarifies that subsequently only entry 0 is dealt with
(indicating that part of the comment was wrong). Finally for there to be
a usable name in slot 1, files_in_use needs to be larger than 1 and slot
1's (rather than slot 0's) name needs to be non-NULL.
Commit 3417bfca67 ("GAS: DWARF-5: Ensure that the 0'th entry in the
directory table contains the current... ") added a "dwarf_level < 5"
check to out_dir_and_file_list(). This rendered dead that branch of the
construct, due to the enclosing if()'s "DWARF2_LINE_VERSION >= 5".
Delete that code as well as the corresponding part of the comment.
While there also drop a redundant "dirs != NULL": "dirs" will always be
non-NULL when dirs_in_use is not zero.
The idea here is to replace expressions like v + 1 + 1 + 1 with v + 3.
* dwarf2dbg.c (set_or_check_view): Remove useless assertion.
Resolve multiple view increments.
* testsuite/gas/elf/dwarf2-18.d: Don't xfail mep.
The result of running etc/update-copyright.py --this-year, fixing all
the files whose mode is changed by the script, plus a build with
--enable-maintainer-mode --enable-cgen-maint=yes, then checking
out */po/*.pot which we don't update frequently.
The copy of cgen was with commit d1dd5fcc38ead reverted as that commit
breaks building of bfp opcodes files.
Update
commit 4780e5e493
Author: Tom de Vries <tdevries@suse.de>
Date: Fri Nov 26 09:59:45 2021 +0100
[gas] Fix file 0 dir with -gdwarf-5
1. Replace i with j in
for (j = 0; i < NUM_MD5_BYTES; ++j)
2. Pass -W to readelf to force CU: in output due to:
if (do_wide || strlen (directory) < 76)
printf (_("CU: %s/%s:\n"), directory, file_table[0].name);
else
printf ("%s:\n", file_table[0].name);
PR gas/28629
* dwarf2dbg.c (out_dir_and_file_list): Fix a typo in commit
4780e5e493.
* testsuite/gas/elf/dwarf-5-nop-for-line-table.d: Pass -W to
readelf.
In out_dir_and_file_list, if file 0 is copied from file 1, only the filename
is copied, and the dir and md5 fields are left to their default values.
Fix this by adding the copy of the dir and md5 fields.
gas/ChangeLog:
2021-11-26 Tom de Vries <tdevries@suse.de>
PR 28629
* dwarf2dbg.c (out_dir_and_file_list): When copying file 1 to file 0,
also copy dir and md5 fields.
* testsuite/gas/i386/dwarf5-line-4.d: Adjust expected output.
Gas uses the directory part, if present, of the .file 0 directive to set
entry 0 of the directory table in DWARF 5, which represents the "current
directory".
Now Gas also uses the file part of the same directive to set entry 0 of the
file table, which represents the "current compilation file". But the latter
need not be located in the former so GCC will use a full path in the file
part when it is passed a full path:
gcc -c /full/path/test.c -save-temps
yields:
.file 0 "/current/directory" "/full/path/test.c"
in the assembly file and:
The Directory Table (offset 0x22, lines 2, columns 1):
Entry Name
0 (indirect line string, offset: 0x25): /current/directory
1 (indirect line string, offset: 0x38): /full/path
The File Name Table (offset 0x30, lines 2, columns 2):
Entry Dir Name
0 0 (indirect line string, offset: 0x43): /full/path/test.c
in the object file. Note the full path and the questionable Dir value in
the 0 entry of the file table.
Fixes segfaults when building aarch64-linux kernel, due to only doing
part of the work necessary when allocating file numbers late. I'd
missed looping over subsegments, which resulted in some u.filename
entries left around and later interpreted as u.view.
PR 28149
* dwarf2dbg.c (purge_generated_debug): Iterate over subsegs too.
(dwarf2_finish): Call do_allocate_filenum for all subsegs too,
in a separate loop before subsegs are chained.
Mixing compiler generated line info with gas generated line info is
generally just confusing. Also .loc directives with non-zero view
fields might reference a previous .loc. It becomes a little more
tricky to locate that previous .loc if there might be gas generated
line info present too. Mind you, we turn off gas generation of line
info on seeing compiler generated line info, so any reference back
won't hit gas generated line info. At least, if the view info is
sane. Unfortunately, gas needs to handle mangled source.
PR 28149
* dwarf2dbg.c (purge_generated_debug): New function.
(dwarf2_directive_filename): Call the above.
(out_debug_line): Don't segfault after purging.
* testsuite/gas/i386/dwarf2-line-4.d: Update expected output.
* testsuite/gas/i386/dwarf4-line-1.d: Likewise.
* testsuite/gas/i386/dwarf5-line-1.d: Likewise.
* testsuite/gas/i386/dwarf5-line-2.d: Likewise.
gcc-11 and gcc-12 pass -gdwarf-5 to gas, in order to prime gas for
DWARF 5 level debug info. Unfortunately it seems there are cases
where the compiler does not emit a .file or .loc dwarf debug directive
before any machine instructions. (Note that the .file directive
typically emitted as the first line of assembly output doesn't count as
a dwarf debug directive. The dwarf .file has a file number before the
file name string.)
This patch delays allocation of file numbers for gas generated line
debug info until the end of assembly, thus avoiding any clashes with
compiler generated file numbers. Two fixes for test case source are
necessary; A .loc can't use a file number that hasn't already been
specified with .file.
A followup patch will remove all the gas generated line info on
seeing a .file directive.
PR 28149
* dwarf2dbg.c (num_of_auto_assigned): Delete.
(current): Update initialisation.
(set_or_check_view): Replace all accesses to view with u.view.
(dwarf2_consume_line_info): Likewise.
(dwarf2_directive_loc): Likewise. Assert that we aren't generating
line info.
(dwarf2_gen_line_info_1): Don't call set_or_check_view on
gas generated line entries.
(dwarf2_gen_line_info): Set and track filenames for gas generated
line entries. Simplify generation of labels.
(get_directory_table_entry): Use filename_cmp when comparing dirs.
(do_allocate_filenum): New function.
(dwarf2_where): Set u.filename and filenum to -1 for gas generated
line entries.
(dwarf2_directive_filename): Remove num_of_auto_assigned handling.
(process_entries): Update view field access. Call
do_allocate_filenum.
* dwarf2dbg.h (struct dwarf2_line_info): Add filename field in
union aliasing view.
* testsuite/gas/i386/dwarf2-line-3.s: Add .file directive.
* testsuite/gas/i386/dwarf2-line-4.s: Likewise.
* testsuite/gas/i386/dwarf2-line-4.d: Update expected output.
* testsuite/gas/i386/dwarf4-line-1.d: Likewise.
* testsuite/gas/i386/dwarf5-line-1.d: Likewise.
* testsuite/gas/i386/dwarf5-line-2.d: Likewise.
DWARF5 allows .file 0 to take an optional directory name. Set the entry
0 of the directory table to the directory name in .file 0.
PR gas/28266
* dwarf2dbg.c (get_directory_table_entry): Add an argument for
the directory name in .file 0 and use it, instead of PWD.
(allocate_filenum): Pass NULL to get_directory_table_entry.
(allocate_filename_to_slot): Pass the incoming dirname to
get_directory_table_entry.
* testsuite/gas/elf/dwarf-5-file0-2.d: New file.
* testsuite/gas/elf/dwarf-5-file0-2.s: Likewise.
* testsuite/gas/elf/elf.exp: Run dwarf-5-file0-2.
* dwarf2dbg.c (get_directory_table_entry): Ensure that dir[0]
contains current working directory.
(out_dir_and_file_list): Likewise.
* testsuite/gas/elf/dwarf-5-dir0.s: New test source file.
* testsuite/gas/elf/dwarf-5-dir0.d: New test driver.
* testsuite/gas/elf/elf.exp: Run the new test.
* testsuite/gas/elf/dwarf-5-file0.d: Adjust expected output.
* testsuite/gas/i386/dwarf5-line-1.d: Likewise.
* testsuite/gas/i386/dwarf5-line-2.d: Likewise.
PR 27221
* dwarf2dbg.c (dwarf2_gen_line_info_1): Don't warn about ignored
line number info when gas is generating it.
* testsuite/gas/elf/dwarf2-20.d: Adjust to not expect warnings.
* testsuite/gas/m68hc11/indexed12.d: Likewise.
* testsuite/gas/elf/elf.exp: Don't run warn-2.
* gas/testsuite/gas/elf/warn-2.s: Delete.
Currently
$ as -o x.o x.s
fails when x.s contains DWARF5 ".file 0" or ".loc 0" directives. Update
assembler to automatically enable DWARF5 support so that
$ gcc -S -g -c x.c
$ gcc -c x.s
works.
PR gas/27195
* dwarf2dbg.c (dwarf2_gen_line_info): Set dwarf_level to 5 if
needed.
(dwarf2_directive_filename): Likewise.
(dwarf2_directive_loc): Likewise.
* testsuite/gas/elf/dwarf-5-file0.d: Pass --gdwarf-3.
* testsuite/gas/lns/lns-diag-1.l: Remove the
"Error: file number less than one" errors.
