diff --git a/lld/ELF/InputFiles.cpp b/lld/ELF/InputFiles.cpp index bad9cc169cd1..64e64ff63b50 100644 --- a/lld/ELF/InputFiles.cpp +++ b/lld/ELF/InputFiles.cpp @@ -643,12 +643,52 @@ void ObjFile::initializeSections(bool ignoreComdats) { continue; const Elf_Shdr &sec = objSections[i]; - if (sec.sh_type == SHT_REL || sec.sh_type == SHT_RELA) - this->sections[i] = createInputSection(i, sec, shstrtab); + if (sec.sh_type == SHT_REL || sec.sh_type == SHT_RELA) { + // Find a relocation target section and associate this section with that. + // Target may have been discarded if it is in a different section group + // and the group is discarded, even though it's a violation of the spec. + // We handle that situation gracefully by discarding dangling relocation + // sections. + const uint32_t info = sec.sh_info; + InputSectionBase *s = getRelocTarget(i, sec, info); + if (!s) + continue; + + // ELF spec allows mergeable sections with relocations, but they are rare, + // and it is in practice hard to merge such sections by contents, because + // applying relocations at end of linking changes section contents. So, we + // simply handle such sections as non-mergeable ones. Degrading like this + // is acceptable because section merging is optional. + if (auto *ms = dyn_cast(s)) { + s = make(ms->file, ms->flags, ms->type, ms->alignment, + ms->data(), ms->name); + sections[info] = s; + } + + if (s->relSecIdx != 0) + error( + toString(s) + + ": multiple relocation sections to one section are not supported"); + s->relSecIdx = i; + + // Relocation sections are usually removed from the output, so return + // `nullptr` for the normal case. However, if -r or --emit-relocs is + // specified, we need to copy them to the output. (Some post link analysis + // tools specify --emit-relocs to obtain the information.) + if (config->copyRelocs) { + auto *isec = make( + *this, sec, check(obj.getSectionName(sec, shstrtab))); + // If the relocated section is discarded (due to /DISCARD/ or + // --gc-sections), the relocation section should be discarded as well. + s->dependentSections.push_back(isec); + sections[i] = isec; + } + continue; + } // A SHF_LINK_ORDER section with sh_link=0 is handled as if it did not have // the flag. - if (!(sec.sh_flags & SHF_LINK_ORDER) || !sec.sh_link) + if (!sec.sh_link || !(sec.sh_flags & SHF_LINK_ORDER)) continue; InputSectionBase *linkSec = nullptr; @@ -828,9 +868,9 @@ template static uint32_t readAndFeatures(const InputSection &sec) { } template -InputSectionBase *ObjFile::getRelocTarget(uint32_t idx, StringRef name, - const Elf_Shdr &sec) { - uint32_t info = sec.sh_info; +InputSectionBase *ObjFile::getRelocTarget(uint32_t idx, + const Elf_Shdr &sec, + uint32_t info) { if (info < this->sections.size()) { InputSectionBase *target = this->sections[info]; @@ -844,18 +884,11 @@ InputSectionBase *ObjFile::getRelocTarget(uint32_t idx, StringRef name, return target; } - error(toString(this) + Twine(": relocation section ") + name + " (index " + - Twine(idx) + ") has invalid sh_info (" + Twine(info) + ")"); + error(toString(this) + Twine(": relocation section (index ") + Twine(idx) + + ") has invalid sh_info (" + Twine(info) + ")"); return nullptr; } -// Create a regular InputSection class that has the same contents -// as a given section. -static InputSection *toRegularSection(MergeInputSection *sec) { - return make(sec->file, sec->flags, sec->type, sec->alignment, - sec->data(), sec->name); -} - template InputSectionBase *ObjFile::createInputSection(uint32_t idx, const Elf_Shdr &sec, @@ -908,10 +941,7 @@ InputSectionBase *ObjFile::createInputSection(uint32_t idx, } } - switch (sec.sh_type) { - case SHT_LLVM_DEPENDENT_LIBRARIES: { - if (config->relocatable) - break; + if (sec.sh_type == SHT_LLVM_DEPENDENT_LIBRARIES && !config->relocatable) { ArrayRef data = CHECK(this->getObj().template getSectionContentsAsArray(sec), this); if (!data.empty() && data.back() != '\0') { @@ -927,45 +957,6 @@ InputSectionBase *ObjFile::createInputSection(uint32_t idx, } return &InputSection::discarded; } - case SHT_RELA: - case SHT_REL: { - // Find a relocation target section and associate this section with that. - // Target may have been discarded if it is in a different section group - // and the group is discarded, even though it's a violation of the - // spec. We handle that situation gracefully by discarding dangling - // relocation sections. - InputSectionBase *target = getRelocTarget(idx, name, sec); - if (!target) - return nullptr; - - // ELF spec allows mergeable sections with relocations, but they are - // rare, and it is in practice hard to merge such sections by contents, - // because applying relocations at end of linking changes section - // contents. So, we simply handle such sections as non-mergeable ones. - // Degrading like this is acceptable because section merging is optional. - if (auto *ms = dyn_cast(target)) { - target = toRegularSection(ms); - this->sections[sec.sh_info] = target; - } - - if (target->relSecIdx != 0) - fatal(toString(this) + - ": multiple relocation sections to one section are not supported"); - target->relSecIdx = idx; - - // Relocation sections are usually removed from the output, so return - // `nullptr` for the normal case. However, if -r or --emit-relocs is - // specified, we need to copy them to the output. (Some post link analysis - // tools specify --emit-relocs to obtain the information.) - if (!config->copyRelocs) - return nullptr; - InputSection *relocSec = make(*this, sec, name); - // If the relocated section is discarded (due to /DISCARD/ or - // --gc-sections), the relocation section should be discarded as well. - target->dependentSections.push_back(relocSec); - return relocSec; - } - } if (name.startswith(".n")) { // The GNU linker uses .note.GNU-stack section as a marker indicating diff --git a/lld/ELF/InputFiles.h b/lld/ELF/InputFiles.h index 1084cf94313b..6febea3f437d 100644 --- a/lld/ELF/InputFiles.h +++ b/lld/ELF/InputFiles.h @@ -286,8 +286,8 @@ private: void initializeSymbols(); void initializeJustSymbols(); - InputSectionBase *getRelocTarget(uint32_t idx, StringRef name, - const Elf_Shdr &sec); + InputSectionBase *getRelocTarget(uint32_t idx, const Elf_Shdr &sec, + uint32_t info); InputSectionBase *createInputSection(uint32_t idx, const Elf_Shdr &sec, StringRef shstrtab); diff --git a/lld/test/ELF/invalid/bad-reloc-target.test b/lld/test/ELF/invalid/bad-reloc-target.test index 6177910d881e..88b4cdf96779 100644 --- a/lld/test/ELF/invalid/bad-reloc-target.test +++ b/lld/test/ELF/invalid/bad-reloc-target.test @@ -1,6 +1,6 @@ # RUN: yaml2obj --docnum=1 %s -o %t1.o # RUN: not ld.lld %t1.o -o /dev/null 2>&1 | FileCheck %s -# CHECK: error: {{.*}}.o: relocation section .rela.text (index 2) has invalid sh_info (0) +# CHECK: error: {{.*}}.o: relocation section (index 2) has invalid sh_info (0) --- !ELF FileHeader: @@ -25,7 +25,7 @@ Symbols: # RUN: yaml2obj --docnum=2 %s -o %t2.o # RUN: not ld.lld %t2.o -o /dev/null 2>&1 | FileCheck %s --check-prefix=ERR2 -# ERR2: error: {{.*}}.o: relocation section .rela.text (index 2) has invalid sh_info (99) +# ERR2: error: {{.*}}.o: relocation section (index 2) has invalid sh_info (99) --- !ELF FileHeader: diff --git a/lld/test/ELF/invalid/multiple-relocations-sections.test b/lld/test/ELF/invalid/multiple-relocations-sections.test index 3f8f66307375..673113f02691 100644 --- a/lld/test/ELF/invalid/multiple-relocations-sections.test +++ b/lld/test/ELF/invalid/multiple-relocations-sections.test @@ -1,6 +1,6 @@ # RUN: yaml2obj %s -o %t1.o # RUN: not ld.lld %t1.o -o /dev/null 2>&1 | FileCheck %s -# CHECK: error: {{.*}}1.o: multiple relocation sections to one section are not supported +# CHECK: error: {{.*}}1.o:(.text): multiple relocation sections to one section are not supported ## The file has two relocation sections referring to a single target section. ## Multiple relocation sections to one section are not supported, check we report this case.