Vendor import of lld trunk r305575:vendor/lld/lld-trunk-r305575

https://llvm.org/svn/llvm-project/lld/trunk@305575

1 files changed, 28 insertions, 9 deletions

diff --git a/ELF/InputFiles.cpp b/ELF/InputFiles.cpp
index 524246ed1d17..3d11239bf88f 100644
--- a/ELF/InputFiles.cpp
+++ b/ELF/InputFiles.cpp
@@ -205,13 +205,27 @@ template <class ELFT>
 StringRef
 elf::ObjectFile<ELFT>::getShtGroupSignature(ArrayRef<Elf_Shdr> Sections,
                                             const Elf_Shdr &Sec) {
+  // Group signatures are stored as symbol names in object files.
+  // sh_info contains a symbol index, so we fetch a symbol and read its name.
   if (this->Symbols.empty())
     this->initSymtab(
         Sections,
         check(object::getSection<ELFT>(Sections, Sec.sh_link), toString(this)));
+
   const Elf_Sym *Sym = check(
       object::getSymbol<ELFT>(this->Symbols, Sec.sh_info), toString(this));
-  return check(Sym->getName(this->StringTable), toString(this));
+  StringRef Signature = check(Sym->getName(this->StringTable), toString(this));
+
+  // As a special case, if a symbol is a section symbol and has no name,
+  // we use a section name as a signature.
+  //
+  // Such SHT_GROUP sections are invalid from the perspective of the ELF
+  // standard, but GNU gold 1.14 (the neweset version as of July 2017) or
+  // older produce such sections as outputs for the -r option, so we need
+  // a bug-compatibility.
+  if (Signature.empty() && Sym->getType() == STT_SECTION)
+    return getSectionName(Sec);
+  return Signature;
 }
 
 template <class ELFT>
@@ -287,8 +301,7 @@ void elf::ObjectFile<ELFT>::initializeSections(
       check(this->getObj().sections(), toString(this));
   uint64_t Size = ObjSections.size();
   this->Sections.resize(Size);
-
-  StringRef SectionStringTable =
+  this->SectionStringTable =
       check(Obj.getSectionStringTable(ObjSections), toString(this));
 
   for (size_t I = 0, E = ObjSections.size(); I < E; I++) {
@@ -318,7 +331,7 @@ void elf::ObjectFile<ELFT>::initializeSections(
       // object files, we want to pass through basically everything.
       if (IsNew) {
         if (Config->Relocatable)
-          this->Sections[I] = createInputSection(Sec, SectionStringTable);
+          this->Sections[I] = createInputSection(Sec);
         continue;
       }
 
@@ -342,7 +355,7 @@ void elf::ObjectFile<ELFT>::initializeSections(
     case SHT_NULL:
       break;
     default:
-      this->Sections[I] = createInputSection(Sec, SectionStringTable);
+      this->Sections[I] = createInputSection(Sec);
     }
 
     // .ARM.exidx sections have a reverse dependency on the InputSection they
@@ -386,10 +399,8 @@ InputSectionBase *toRegularSection(MergeInputSection *Sec) {
 
 template <class ELFT>
 InputSectionBase *
-elf::ObjectFile<ELFT>::createInputSection(const Elf_Shdr &Sec,
-                                          StringRef SectionStringTable) {
-  StringRef Name = check(
-      this->getObj().getSectionName(&Sec, SectionStringTable), toString(this));
+elf::ObjectFile<ELFT>::createInputSection(const Elf_Shdr &Sec) {
+  StringRef Name = getSectionName(Sec);
 
   switch (Sec.sh_type) {
   case SHT_ARM_ATTRIBUTES:
@@ -521,6 +532,12 @@ elf::ObjectFile<ELFT>::createInputSection(const Elf_Shdr &Sec,
   return make<InputSection>(this, &Sec, Name);
 }
 
+template <class ELFT>
+StringRef elf::ObjectFile<ELFT>::getSectionName(const Elf_Shdr &Sec) {
+  return check(this->getObj().getSectionName(&Sec, SectionStringTable),
+               toString(this));
+}
+
 template <class ELFT> void elf::ObjectFile<ELFT>::initializeSymbols() {
   SymbolBodies.reserve(this->Symbols.size());
   for (const Elf_Sym &Sym : this->Symbols)
@@ -804,6 +821,8 @@ static uint8_t getBitcodeMachineKind(StringRef Path, const Triple &T) {
   case Triple::arm:
   case Triple::thumb:
     return EM_ARM;
+  case Triple::avr:
+    return EM_AVR;
   case Triple::mips:
   case Triple::mipsel:
   case Triple::mips64: