On
#define A(n) int foo1##n(void) { return 1##n; }
#define B(n) A(n##0) A(n##1) A(n##2) A(n##3) A(n##4) A(n##5) A(n##6) A(n##7) A(n##8) A(n##9)
#define C(n) B(n##0) B(n##1) B(n##2) B(n##3) B(n##4) B(n##5) B(n##6) B(n##7) B(n##8) B(n##9)
#define D(n) C(n##0) C(n##1) C(n##2) C(n##3) C(n##4) C(n##5) C(n##6) C(n##7) C(n##8) C(n##9)
#define E(n) D(n##0) D(n##1) D(n##2) D(n##3) D(n##4) D(n##5) D(n##6) D(n##7) D(n##8) D(n##9)
E(0) E(1) E(2) D(30) D(31) C(320) C(321) C(322) C(323) C(324) C(325)
B(3260) B(3261) B(3262) B(3263) A(32640) A(32641) A(32642)
testcase with
./xgcc -B ./ -c -g -fpic -ffat-lto-objects -flto -O0 -o foo1.o foo1.c -ffunction-sections
./xgcc -B ./ -shared -g -fpic -flto -O0 -o foo1.so foo1.o
/tmp/ccTW8mBm.debug.temp.o: file not recognized: file format not recognized
(testcase too slow to be included into testsuite).
The problem is clearly reported by readelf:
readelf: foo1.o.debug.temp.o: Warning: Section 2 has an out of range sh_link value of 65321
readelf: foo1.o.debug.temp.o: Warning: Section 5 has an out of range sh_link value of 65321
readelf: foo1.o.debug.temp.o: Warning: Section 10 has an out of range sh_link value of 65323
readelf: foo1.o.debug.temp.o: Warning: [ 2]: Link field (65321) should index a symtab section.
readelf: foo1.o.debug.temp.o: Warning: [ 5]: Link field (65321) should index a symtab section.
readelf: foo1.o.debug.temp.o: Warning: [10]: Link field (65323) should index a string section.
because simple_object_elf_copy_lto_debug_sections doesn't adjust sh_info and
sh_link fields in ElfNN_Shdr if they are in between SHN_{LO,HI}RESERVE
inclusive. Not adjusting those is incorrect though, SHN_{LO,HI}RESERVE
range is only relevant to the 16-bit fields, mainly st_shndx in ElfNN_Sym
where if one needs >= SHN_LORESERVE section number, SHN_XINDEX should be
used instead and .symtab_shndx section should contain the real section
index, and in ElfNN_Ehdr e_shnum and e_shstrndx fields, where if >=
SHN_LORESERVE value is needed it should put those into
Shdr[0].sh_{size,link}. But, sh_{link,info} are 32-bit fields which can
contain any section index.
Note, as simple-object-elf.c mentions, binutils from 2.12 to 2.18 (so before
2011) used to mishandle the > 63.75K sections case and assumed there is a
hole in between the sections, but what
simple_object_elf_copy_lto_debug_sections does wouldn't help in that case
for the debug temp object creation, we'd need to detect the case also in
that routine and take it into account in the remapping etc. I think
it is not worth it given that it is over 10 years, if somebody needs
63.75K or more sections, better use more recent binutils.
2022-02-22 Jakub Jelinek <jakub@redhat.com>
PR lto/104617
* simple-object-elf.c (simple_object_elf_match): Fix up URL
in comment.
(simple_object_elf_copy_lto_debug_sections): Remap sh_info and
sh_link even if they are in the SHN_LORESERVE .. SHN_HIRESERVE
range (inclusive).
readelf -S prints:
There are 81999 section headers, starting at offset 0x1f488060:
Section Headers:
[Nr] Name Type Address Off Size ES Flg Lk Inf Al
[ 0] NULL 0000000000000000 000000 01404f 00 81998 0 0
[ 1] .group GROUP 0000000000000000 000040 000008 04 81995 105027 4
...
[81995] .symtab SYMTAB 0000000000000000 d5d9298 2db310 18 81997 105026 8
[81996] .symtab_shndx SYMTAB SECTION INDICES 0000000000000000 d8b45a8 079dd8 04 81995 0 4
[81997] .strtab STRTAB 0000000000000000 d92e380 80460c 00 0 0 1
...
Looking at the documentation:
Table 7–15 ELF sh_link and sh_info Interpretation
sh_type - sh_link
SHT_SYMTAB - The section header index of the associated string table.
SHT_SYMTAB_SHNDX - The section header index of the associated symbol table.
As seen, sh_link of a SHT_SYMTAB always points to a .strtab and readelf
confirms that.
So we need to use reverse mapping taken from
[81996] .symtab_shndx SYMTAB SECTION INDICES 0000000000000000 d8b45a8 079dd8 04 81995 0 4
where sh_link points to 81995.
libiberty/ChangeLog:
PR lto/97290
* simple-object-elf.c (simple_object_elf_copy_lto_debug_sections):
Use sh_link of a .symtab_shndx section.
Unused global UNDEFs can have side-effects in some circumstances so
the following patch avoids them by treating them the same as other
to be discarded DEFs - make them local.
2020-08-03 Richard Biener <rguenther@suse.de>
PR lto/96385
libiberty/
* simple-object-elf.c
(simple_object_elf_copy_lto_debug_sections): Localize global
UNDEFs and reuse the prevailing name.
2019-08-27 Martin Liska <mliska@suse.cz>
PR lto/91478
* simple-object-elf.c (simple_object_elf_copy_lto_debug_sections):
First find a WEAK HIDDEN symbol in symbol table that will be
preserved. Later, use the symbol name for all removed symbols.
From-SVN: r274955
2019-07-22 Martin Liska <mliska@suse.cz>
* config/avr/avr.c (avr_asm_output_aligned_decl_common): Update
comment.
* toplev.c (compile_file): Do not emit __gnu_lto_v1 symbol.
2019-07-22 Martin Liska <mliska@suse.cz>
* config/pa/stublib.c: Remove stub symbol __gnu_lto_v1.
* config/pa/t-stublib: Likewise.
2019-07-22 Martin Liska <mliska@suse.cz>
* simple-object-elf.c (simple_object_elf_copy_lto_debug_sections):
Do not search for gnu_lto_v1, but search for first '\0'.
From-SVN: r273662
2018-01-11 Richard Biener <rguenther@suse.de>
Rainer Orth <ro@CeBiTec.Uni-Bielefeld.DE>
PR lto/81968
libiberty/
* simple-object-common.h (struct simple_object_functions):
Change copy_lto_debug_sections callback signature.
* simple-object-elf.c (SHN_HIRESERVE, SHT_SYMTAB_SHNDX,
SHF_INFO_LINK): Add defines.
(simple_object_elf_copy_lto_debug_sections): Instead of
leaving not to be copied sections empty unnamed SHT_NULL
remove them from the target section headers and adjust section
reference everywhere. Handle SHN_XINDEX in the symbol table
processing properly.
* simple-object.c (handle_lto_debug_sections): Change
interface to return a modified string and handle renaming
of relocation sections.
Co-Authored-By: Rainer Orth <ro@CeBiTec.Uni-Bielefeld.DE>
From-SVN: r256528
2017-01-02 Richard Biener <rguenther@suse.de>
PR lto/83452
* simple-object-elf.c (simple_object_elf_copy_lto_debug_section):
Do not use UNDEF locals for removed symbols but instead just
define them in the first prevailing section and with no name.
Use the same gnu_lto_v1 name for all removed globals we promote to
WEAK UNDEFs so hpux can use a stub to provide this symbol. Clear
sh_info and sh_link in removed sections.
From-SVN: r256069
2017-10-30 Richard Biener <rguenther@suse.de>
PR lto/82757
* simple-object-elf.c (simple_object_elf_copy_lto_debug_sections):
Strip two leading _s from the __gnu_lto_* symbols.
From-SVN: r254219
The problem with making discarded symbols hidden is that the
non-default visibility is sticky. When symbols other than the
__gnu_lto ones are discarded that turns out to be a bad idea.
PR lto/82687
PR lto/82575
* simple-object-elf.c (simple_object_elf_copy_lto_debug_sections):
Only make __gnu_lto symbols hidden. Delete outdated comment.
Silence ISO C warning.
From-SVN: r254042
If __gnu_lto_slim is global, undefined, default visibility in the
early debug object, then it finds its way into .dynsym when creating
shared libraries. __gnu_lto_slim in a symbol table (.dynsym or
.symtab) signals nm and other binutils that the object is an LTO
object needing a plugin, but that isn't the case for the ld liblti-17
tests. So, make __gnu_lto_slim hidden to prevent it becoming
dynamic. Further, make it weak because some linkers may warn on
finding an undefined global non-default visibility symbol.
PR lto/82575
* simple-object-elf.c (simple_object_elf_copy_lto_debug_sections):
Make discarded non-local symbols weak and hidden.
From-SVN: r253914
PR lto/82598
* simple-object.c (handle_lto_debug_sections): Copy over also
.note.GNU-stack section with unchanged name.
* simple-object-elf.c (SHF_EXECINSTR): Define.
(simple_object_elf_copy_lto_debug_section): Drop SHF_EXECINSTR bit
on .note.GNU-stack section.
From-SVN: r253851
2017-08-28 Richard Biener <rguenther@suse.de>
PR lto/81968
* simple-object-elf.c (simple_object_elf_copy_lto_debug_section):
Adjust field with for sh_type write, set SHF_EXCLUDE only for
removed sections.
From-SVN: r251384
2017-08-22 Richard Biener <rguenther@suse.de>
PR lto/81925
* simple-object-elf.c (simple_object_elf_write_shdr): Adjust
type of sh_addralign and sh_entsize and properly write
sh_entsize as Elf_Addr.
(simple_object_elf_write_to_file): Read sh_entsize as Elf_Addr.
From-SVN: r251276
2017-08-21 Richard Biener <rguenther@suse.de>
include/
* simple-object.h (simple_object_copy_lto_debug_sections): New
function.
libiberty/
* simple-object-common.h (struct simple_object_functions): Add
copy_lto_debug_sections hook.
* simple-object.c: Include fcntl.h.
(handle_lto_debug_sections): New helper function.
(simple_object_copy_lto_debug_sections): New function copying
early LTO debug sections to regular debug sections in a new file.
(simple_object_start_write): Handle NULL segment_name.
* simple-object-coff.c (simple_object_coff_functions): Adjust
for not implemented copy_lto_debug_sections hook.
* simple-object-mach-o.c (simple_object_mach_o_functions): Likewise.
* simple-object-xcoff.c (simple_object_xcoff_functions): Likewise.
* simple-object-elf.c (SHT_NULL, SHT_SYMTAB, SHT_RELA, SHT_REL,
SHT_GROUP): Add various sectopn header types.
(SHF_EXCLUDE): Add flag.
(Elf32_External_Sym, Elf64_External_Sym): Add symbol struct.
(ELF_ST_BIND, ELF_ST_TYPE, ELF_ST_INFO): Add accessors.
(STT_OBJECT, STT_FUNC, STT_TLS, STT_GNU_IFUNC): Add Symbol types.
(STV_DEFAULT): Add symbol visibility.
(SHN_COMMON): Add special section index name.
(struct simple_object_elf_write): New.
(simple_object_elf_start_write): Adjust for new private data.
(simple_object_elf_write_shdr): Pass in values for all fields
we write.
(simple_object_elf_write_to_file): Adjust. Copy from recorded
section headers if requested.
(simple_object_elf_release_write): Release private data.
(simple_object_elf_copy_lto_debug_sections): Copy and rename sections
as denoted by PFN and all their dependences, symbols and relocations
to the empty destination file.
(simple_object_elf_functions): Adjust for copy_lto_debug_sections hook.
gcc/
* debug.h (struct gcc_debug_hooks): Add die_ref_for_decl and
register_external_die hooks.
(debug_false_tree_charstarstar_uhwistar): Declare.
(debug_nothing_tree_charstar_uhwi): Likewise.
* debug.c (do_nothing_debug_hooks): Adjust.
(debug_false_tree_charstarstar_uhwistar): New do nothing.
(debug_nothing_tree_charstar_uhwi): Likewise.
* dbxout.c (dbx_debug_hooks): Adjust.
(xcoff_debug_hooks): Likewise.
* sdbout.c (sdb_debug_hooks): Likewise.
* vmsdbgout.c (vmsdbg_debug_hooks): Likewise.
* dwarf2out.c (macinfo_label_base): New global.
(dwarf2out_register_external_die): New function for the
register_external_die hook.
(dwarf2out_die_ref_for_decl): Likewise for die_ref_for_decl.
(dwarf2_debug_hooks): Use them.
(dwarf2_lineno_debug_hooks): Adjust.
(struct die_struct): Add with_offset flag.
(DEBUG_LTO_DWO_INFO_SECTION, DEBUG_LTO_INFO_SECTION,
DEBUG_LTO_DWO_ABBREV_SECTION, DEBUG_LTO_ABBREV_SECTION,
DEBUG_LTO_DWO_MACINFO_SECTION, DEBUG_LTO_MACINFO_SECTION,
DEBUG_LTO_DWO_MACRO_SECTION, DEBUG_LTO_MACRO_SECTION,
DEBUG_LTO_LINE_SECTION, DEBUG_LTO_DWO_STR_OFFSETS_SECTION,
DEBUG_LTO_STR_DWO_SECTION, DEBUG_STR_LTO_SECTION): New macros
defining section names for the early LTO debug variants.
(reset_indirect_string): New helper.
(add_AT_external_die_ref): Helper for dwarf2out_register_external_die.
(print_dw_val): Add support for offsetted symbol references.
(get_ultimate_context): Split out from is_cxx.
(is_cxx): Use get_ultimate_context.
(is_fortran): Add decl overload.
(compute_comp_unit_symbol): Split out worker from
compute_section_prefix.
(compute_section_prefix): Call compute_comp_unit_symbol and
set comdat_type_p here.
(output_die): Skip DIE symbol output for the LTO added one.
Handle DIE symbol references with offset.
(output_comp_unit): Guard section name mangling properly.
For LTO debug sections emit a symbol at the section beginning
which we use to refer to its DIEs.
(add_abstract_origin_attribute): For DIEs registered via
dwarf2out_register_external_die directly refer to the early
DIE rather than indirectly through the shadow one we created.
Remove obsolete call to dwarf2out_abstract_function for
non-function/block origins.
(gen_array_type_die): When generating early LTO debug do
not emit DW_AT_string_length.
(gen_formal_parameter_die): Do not re-create DIEs for PARM_DECLs
late when in LTO. As suggested place a gcc_unreachable for
the DECL_ABSTRACT_P case.
(gen_subprogram_die): Avoid another specification DIE
for early built declarations/definitions for the late LTO case.
(gen_variable_die): Add type references for late duplicated VLA dies
when in late LTO.
(gen_inlined_subroutine_die): Do not call dwarf2out_abstract_function,
we have the abstract instance already.
(process_scope_var): Adjust decl DIE contexts in LTO which
first puts them in limbo.
(gen_decl_die): Do not generate type DIEs late apart from
types for VLAs or for decls we do not yet have a DIE. Do not
call dwarf2out_abstract_function late.
(dwarf2out_early_global_decl): Make sure to create DIEs
for abstract instances of a decl first.
(dwarf2out_late_global_decl): Adjust comment.
(output_macinfo_op): With multiple macro sections use
macinfo_label_base to distinguish labels.
(output_macinfo): Likewise. Update macinfo_label_base.
Pass in the line info label.
(note_variable_value_in_expr): When generating LTO resolve
all variable values here by generating DIEs as needed.
(init_sections_and_labels): Add early LTO debug flag parameter
and generate different sections and names if set. Add generation
counter for the labels so we can have multiple of them.
(reset_dies): Helper to allow DIEs to be output multiple times.
(dwarf2out_finish): When outputting DIEs to the fat part of an
LTO object first reset DIEs.
(dwarf2out_early_finish): Output early DIEs when generating LTO.
(modified_type_die): Check for decl_ultimate_origin being self
before recursing.
(gen_type_die_with_usage): Likewise.
(gen_typedef_die): Allow decl_ultimate_origin being self.
(set_decl_abstract_flags): Remove.
(set_block_abstract_flags): Likewise.
(dwarf2out_abstract_function): Treat the early generated DIEs
as the abstract copy and only add DW_AT_inline and
DW_AT_artificial here and call set_decl_origin_self.
If the DIE has an abstract origin don't do anything.
* tree.c (free_lang_data): Build a dummy TRANSLATION_UNIT_DECL
if we have none yet (Go fails to build one, PR78628).
(variably_modified_type_p): Prevent endless recursion for Ada
cyclic pointer types.
* lto-streamer-in.c: Include debug.h.
(dref_queue): New global.
(lto_read_tree_1): Stream in DIE references.
(lto_input_tree): Register DIE references.
(input_function): Stream DECL_DEBUG_ARGS.
* lto-streamer-out.c: Include debug.h.
(lto_write_tree_1): Output DIE references.
(DFS::DFS_write_tree_body): Follow DECL_ABSTRACT_ORIGIN.
Force a TRANSLATION_UNIT_DECL DECL_CONTEXT for file-scope decls.
(output_function): Stream DECL_DEBUG_ARGS.
* tree-streamer-in.c (lto_input_ts_decl_common_tree_pointers):
Stream DECL_ABSTRACT_ORIGIN.
* tree-streamer-out.c (write_ts_decl_common_tree_pointers): Likewise.
(write_ts_decl_minimal_tree_pointers): Force a TRANSLATION_UNIT_DECL
DECL_CONTEXT for file-scope decls.
* lto-streamer.h (struct dref_entry): Declare.
(dref_queue): Likewise.
* cfgexpand.c (pass_expand::execute): Do not call the
outlining_inline_function hook here.
* lto-wrapper.c (debug_obj): New global.
(tool_cleanup): Unlink it if required.
(debug_objcopy): New function.
(run_gcc): Handle early debug sections in the IL files by
extracting them to separate files, partially linkin them and
feeding the result back as result to the linker.
* config/darwin.h (DEBUG_LTO_INFO_SECTION, DEBUG_LTO_ABBREV_SECTION,
DEBUG_LTO_MACINFO_SECTION, DEBUG_LTO_LINE_SECTION,
DEBUG_STR_LTO_SECTION, DEBUG_LTO_MACRO_SECTION): Put early debug
sections into a separate segment.
* config/darwin.c (darwin_asm_named_section): Handle __GNU_DWARF_LTO
segments.
(darwin_asm_dwarf_section): Likewise.
(darwin_asm_output_dwarf_offset): Likewise.
* config/i386/i386.c (make_resolver_func): Set DECL_IGNORED_P.
lto/
* lto.c (unify_scc): Truncate DIE reference queue for dropped SCCs.
(lto_read_decls): Process TRANSLATION_UNIT_DECLs. Remove
TYPE_DECL debug processing, register DIE references from
prevailing SCCs with the debug machinery.
(lto_section_with_id): Handle LTO debug sections.
libstdc++/
* testsuite/libstdc++-prettyprinters/prettyprinters.exp: Run all
tests with -flto as well if supported.
testsuite/
* c-c++-common/asan/global-overflow-1.c: Adjust diagnostic location
regex to handle the LTO case.
* c-c++-common/asan/heap-overflow-1.c: Likewise.
* c-c++-common/asan/misalign-1.c: Likewise.
* c-c++-common/asan/misalign-2.c: Likewise.
* c-c++-common/asan/null-deref-1.c: Likewise.
* c-c++-common/asan/stack-overflow-1.c: Likewise.
* c-c++-common/asan/strncpy-overflow-1.c: Likewise.
* c-c++-common/asan/use-after-free-1.c: Likewise.
* c-c++-common/asan/alloca_big_alignment.c: Likewise.
* c-c++-common/asan/alloca_detect_custom_size.c: Likewise.
* c-c++-common/asan/alloca_overflow_partial.c: Likewise.
* c-c++-common/asan/alloca_overflow_right.c: Likewise.
* c-c++-common/asan/alloca_underflow_left.c: Likewise.
* g++.dg/asan/large-func-test-1.C: Likewise.
* gfortran.dg/save_6.f90: Add -flto -g variant of save_5.f90.
From-SVN: r251220
* simple-object-elf.c (simple_object_elf_write_ehdr): Correctly
handle objects with more than SHN_LORESERVE sections.
(simple_object_elf_write_shdr): Add sh_link parameter.
(simple_object_elf_write_to_file): Correctly handle objects with
more than SHN_LORESERVE sections.
From-SVN: r215394
