[llvm-objcopy] Add --strip-unneeded option

Differential Revision: https://reviews.llvm.org/D46896

llvm-svn: 333267

1 files changed, 16 insertions, 0 deletions

diff --git a/llvm/tools/llvm-objcopy/Object.cpp b/llvm/tools/llvm-objcopy/Object.cpp
index efb3207aa8d..c00477a1980 100644
--- a/llvm/tools/llvm-objcopy/Object.cpp
+++ b/llvm/tools/llvm-objcopy/Object.cpp
@@ -50,6 +50,7 @@ void SectionBase::removeSectionReferences(const SectionBase *Sec) {}
 void SectionBase::removeSymbols(function_ref<bool(const Symbol &)> ToRemove) {}
 void SectionBase::initialize(SectionTableRef SecTable) {}
 void SectionBase::finalize() {}
+void SectionBase::markSymbols() {}
 
 template <class ELFT> void ELFWriter<ELFT>::writeShdr(const SectionBase &Sec) {
   uint8_t *Buf = BufPtr->getBufferStart();
@@ -255,6 +256,11 @@ const Symbol *SymbolTableSection::getSymbolByIndex(uint32_t Index) const {
   return Symbols[Index].get();
 }
 
+Symbol *SymbolTableSection::getSymbolByIndex(uint32_t Index) {
+  return const_cast<Symbol *>(
+      static_cast<const SymbolTableSection *>(this)->getSymbolByIndex(Index));
+}
+
 template <class ELFT>
 void ELFSectionWriter<ELFT>::visit(const SymbolTableSection &Sec) {
   uint8_t *Buf = Out.getBufferStart();
@@ -352,6 +358,11 @@ void RelocationSection::removeSymbols(
             "' because it is named in a relocation");
 }
 
+void RelocationSection::markSymbols() {
+  for (const Relocation &Reloc : Relocations)
+    Reloc.RelocSymbol->Referenced = true;
+}
+
 void SectionWriter::visit(const DynamicRelocationSection &Sec) {
   std::copy(std::begin(Sec.Contents), std::end(Sec.Contents),
             Out.getBufferStart() + Sec.Offset);
@@ -384,6 +395,11 @@ void GroupSection::removeSymbols(function_ref<bool(const Symbol &)> ToRemove) {
   }
 }
 
+void GroupSection::markSymbols() {
+  if (Sym)
+    Sym->Referenced = true;
+}
+
 void Section::initialize(SectionTableRef SecTable) {
   if (Link != ELF::SHN_UNDEF)
     LinkSection =