llvm-project/lld/test/ELF/comdat-discarded-ppc64.s

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[ELF][PPC64] Don't report "relocation refers to a discarded section" for .toc Summary: clang (as of 2019-06-12) / gcc (as of 8.2.1) PPC64 may emit a .rela.toc which references an embedded switch table in a discarded .rodata/.text section. The .toc and the .rela.toc are incorrectly not placed in the comdat. Technically a relocation from outside the group is not allowed by the ELF spec: > A symbol table entry with STB_LOCAL binding that is defined relative > to one of a group's sections, and that is contained in a symbol table > section that is not part of the group, must be discarded if the group > members are discarded. References to this symbol table entry from > outside the group are not allowed. Don't report errors to work around the bug. This should fix the ppc64le-lld-multistage-test bot while linking llvm-tblgen: ld.lld: error: relocation refers to a discarded section: .rodata._ZNK4llvm3MVT13getSizeInBitsEv >>> defined in utils/TableGen/CMakeFiles/llvm-tblgen.dir/CodeGenRegisters.cpp.o >>> referenced by CodeGenRegisters.cpp >>> utils/TableGen/CMakeFiles/llvm-tblgen.dir/CodeGenRegisters.cpp.o:(.toc+0x0) Some other PPC specific sections may have similar problems. We can blacklist more section names when problems occur. // A simple program that reproduces the bug. // Note .rela.toc (outside the group) references a section symbol (STB_LOCAL) in a group. void puts(const char *); struct A { void foo(int a) { switch (a) { case 0: puts("0"); break; case 1: puts("1"); puts("1"); break; case 2: puts("2"); break; case 3: puts("3"); puts("4"); break; case 4: puts("4"); break; case 5: puts("5"); puts("5"); break; case 6: puts("6"); break; } } int a; }; void foo(A x) { x.foo(x.a); } Reviewers: ruiu, sfertile, espindola Reviewed By: ruiu Subscribers: emaste, nemanjai, arichardson, kbarton, jsji, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D63182 llvm-svn: 363126
2019-06-12 15:35:42 +08:00
# REQUIRES: ppc
# RUN: llvm-mc -filetype=obj -triple=powerpc64le %s -o %t.o
# RUN: ld.lld %t.o %t.o -o /dev/null
# RUN: ld.lld -r --fatal-warnings %t.o %t.o -o /dev/null
## clang/gcc PPC64 may emit a .rela.toc which references a switch table in a
## discarded .rodata/.text section. The .toc and the .rela.toc are incorrectly
## not placed in the comdat.
## Don't error "relocation refers to a discarded section".
.section .text.foo,"axG",@progbits,foo,comdat
.globl foo
foo:
.L0:
.section .toc,"aw"
.quad .L0