Many profile tests FAIL due to SHF_GNU_RETAIN

[rorth]

Bugzilla Link	49437
Resolution	FIXED
Resolved on	Oct 11, 2021 20:29
Version	trunk
OS	Solaris
Blocks	#51489
CC	@MaskRay,@tstellar
Fixed by commit(s)	7bbbf29 aac4fe3

Extended Description

Recently dozens of Profile tests began to FAIL on Solaris (both sparc and x86,
32 and 64-bit):

Profile-i386 :: Posix/instrprof-value-prof-shared.test
Profile-i386 :: Posix/instrprof-visibility.cpp
Profile-i386 :: coverage-inline.cpp
Profile-i386 :: coverage_comments.cpp
Profile-i386 :: coverage_emptylines.cpp
Profile-i386 :: infinite_loop.c
Profile-i386 :: instrprof-basic.c
Profile-i386 :: instrprof-dump.c
Profile-i386 :: instrprof-hostname.c
Profile-i386 :: instrprof-icall-promo.test
Profile-i386 :: instrprof-merge.c
Profile-i386 :: instrprof-merging.cpp
Profile-i386 :: instrprof-override-filename-then-reset-default.c
Profile-i386 :: instrprof-override-filename-with-env.c
Profile-i386 :: instrprof-override-filename.c
Profile-i386 :: instrprof-reset-counters.c
Profile-i386 :: instrprof-set-file-object-merging.c
Profile-i386 :: instrprof-set-file-object.c
Profile-i386 :: instrprof-set-filename-then-reset-default.c
Profile-i386 :: instrprof-set-filename.c
Profile-i386 :: instrprof-value-prof-2.c
Profile-i386 :: instrprof-value-prof-evict.test
Profile-i386 :: instrprof-value-prof-reset.c
Profile-i386 :: instrprof-value-prof.c
Profile-i386 :: instrprof-value-prof.test
Profile-i386 :: instrprof-without-libc.c
Profile-i386 :: instrprof-write-file-atexit-explicitly.c
Profile-i386 :: instrprof-write-file-only.c
Profile-i386 :: instrprof-write-file.c
Profile-i386 :: runtime_infinite.c

The failure mode is always the same:

$ /var/llvm/dist-amd64-release-stage2-A/tools/clang/stage2-bins/./bin/clang --driver-mode=g++ -m32 -fprofile-instr-generate -fcoverage-mapping -o /var/llvm/dist-amd64-release-stage2-A/tools/clang/stage2-bins/projects/compiler-rt/test/profile/Profile-i386/Output/coverage_emptylines.cpp.tmp /var/llvm/dist-amd64-release-stage2-A/tools/clang/stage2-bins/projects/compiler-rt/test/profile/Profile-i386/Output/coverage_emptylines.cpp.tmp.stripped.cpp -save-temps
ld: fatal: symbol '__covrec_DB956436E78DD5FAu' in file coverage_emptylines.cpp.tmp.stripped.o associated with invalid section[8]
clang-13: error: linker command failed with exit code 1 (use -v to see invocation)

That section is

Section Header[8]: sh_name: __llvm_covfun
sh_addr: 0 sh_flags: [ SHF_GROUP SHF_SUNW_ABSENT ]
sh_size: 0xb0 sh_type: [ SHT_PROGBITS ]
sh_offset: 0x108 sh_entsize: 0
sh_link: 0 sh_info: 0
sh_addralign: 0x8

where <sys/elf.h> has

#define SHF_SUNW_ABSENT 0x00200000 /* section data not present */

However, looking at the assembler output, this has nothing to do with
SHF_SUNW_ABSENT, but the flag is rather SHF_GNU_RETAIN which has the same
value. However, the object files isn't marked as ELFOSABI_GNU as it should
when using a GNU extension, but has

$ elfdump -e coverage_emptylines.cpp.tmp.stripped.o

ELF Header
ei_magic: { 0x7f, E, L, F }
ei_class: ELFCLASS32 ei_data: ELFDATA2LSB
ei_osabi: ELFOSABI_NONE ei_abiversion: 0
e_machine: EM_386 e_version: EV_CURRENT
e_type: ET_REL
e_flags: 0
e_entry: 0 e_ehsize: 52 e_shstrndx: 1
e_shoff: 0x560 e_shentsize: 40 e_shnum: 21
e_phoff: 0 e_phentsize: 0 e_phnum: 0

Solaris ld is very unlikely to ever support SHF_GNU_RETAIN and the integrated
assembler shouldn't emit it. Unfortunately, even with -fbinutils-version=none
this remains unchanged.

[rorth]

Fixed for main by https://reviews.llvm.org/D107747. Required on release/13.x
branch, too.

[tstellar]

Merged: aac4fe3

[tstellar]

mentioned in issue #51489