diff --git a/lld/ELF/Writer.cpp b/lld/ELF/Writer.cpp --- a/lld/ELF/Writer.cpp +++ b/lld/ELF/Writer.cpp @@ -711,23 +711,29 @@ if (!osd) continue; OutputSection &osec = osd->osec; - auto i = llvm::find_if(osec.commands, [](SectionCommand *cmd) { - if (auto *isd = dyn_cast(cmd)) - return !isd->sections.empty(); - return false; - }); - if (i == osec.commands.end()) - continue; - InputSectionBase *isec = cast(*i)->sections[0]; + InputSectionBase *isec = nullptr; + // Iterate over all input sections and add a STT_SECTION symbol if any input + // section may be a relocation target. + for (SectionCommand *cmd : osec.commands) { + auto *isd = dyn_cast(cmd); + if (!isd) + continue; + for (InputSectionBase *s : isd->sections) { + // Relocations are not using REL[A] section symbols. + if (s->type == SHT_REL || s->type == SHT_RELA) + continue; - // Relocations are not using REL[A] section symbols. - if (isec->type == SHT_REL || isec->type == SHT_RELA) - continue; + // Unlike other synthetic sections, mergeable output sections contain + // data copied from input sections, and there may be a relocation + // pointing to its contents if -r or --emit-reloc is given. + if (isa(s) && !(s->flags & SHF_MERGE)) + continue; - // Unlike other synthetic sections, mergeable output sections contain data - // copied from input sections, and there may be a relocation pointing to its - // contents if -r or --emit-reloc is given. - if (isa(isec) && !(isec->flags & SHF_MERGE)) + isec = s; + break; + } + } + if (!isec) continue; // Set the symbol to be relative to the output section so that its st_value diff --git a/lld/test/ELF/emit-relocs-synthetic.s b/lld/test/ELF/emit-relocs-synthetic.s new file mode 100644 --- /dev/null +++ b/lld/test/ELF/emit-relocs-synthetic.s @@ -0,0 +1,54 @@ +# REQUIRES: x86 +## Regression test: add STT_SECTION even if synthetic sections are mixed with +## regular input sections. + +# RUN: rm -rf %t && split-file %s %t +# RUN: llvm-mc -filetype=obj -triple=x86_64 %t/a.s -o %t/a.o +# RUN: ld.lld --emit-relocs --no-relax -T %t/1.t %t/a.o -o %t/a1 +# RUN: llvm-objdump -dr %t/a1 | FileCheck %s --check-prefixes=CHECK,CHECK1 +# RUN: ld.lld --emit-relocs --no-relax -T %t/2.t %t/a.o -o %t/a2 +# RUN: llvm-objdump -dr %t/a2 | FileCheck %s --check-prefixes=CHECK,CHECK2 + +# CHECK: <_start>: +## %t/a1: bss is at offset 17. bss-4 = .bss + 0xd +## %t/a2: bss is at offset 16. bss-4 = .bss + 0xc +# CHECK-NEXT: movl [[#]](%rip), %eax +# CHECK1-NEXT: R_X86_64_PC32 .bss+0xd +# CHECK2-NEXT: R_X86_64_PC32 .bss+0xc +# CHECK-NEXT: movl [[#]](%rip), %eax +# CHECK-NEXT: R_X86_64_PC32 common-0x4 +# CHECK-NEXT: movl [[#]](%rip), %eax +## %t/a1: input .data is at offset 8. 8-4 = 0x4 +## %t/a2: input .data is at offset 0. 0-4 = -0x4 +# CHECK1-NEXT: R_X86_64_GOTPCRELX .data+0x4 +# CHECK2-NEXT: R_X86_64_GOTPCRELX .data-0x4 + +#--- a.s +.globl _start +_start: + movl bss(%rip), %eax + movl common(%rip), %eax +## Compilers don't produce this. We just check the behavior. + movl .data@gotpcrel(%rip), %eax + +.section .data,"aw",@progbits +.quad 0 + +.section .bss,"aw",@nobits +.space 16 +bss: +.byte 0 + +.comm common,1,1 + +#--- 1.t +SECTIONS { + .data : { *(.got) *(.data) } + .bss : { *(COMMON) *(.bss) } +} + +#--- 2.t +SECTIONS { + .data : { *(.data) *(.got) } + .bss : { *(.bss) *(COMMON) } +}