Index: llvm/trunk/test/tools/llvm-objcopy/ELF/Inputs/compress-debug-sections.yaml
===================================================================
--- llvm/trunk/test/tools/llvm-objcopy/ELF/Inputs/compress-debug-sections.yaml
+++ llvm/trunk/test/tools/llvm-objcopy/ELF/Inputs/compress-debug-sections.yaml
@@ -18,4 +18,15 @@
       - Offset:          0x1
         Symbol:          .debug_foo
         Type:            R_X86_64_32
+      - Offset:          0x2
+        Symbol:          .notdebug_foo
+        Type:            R_X86_64_32
+Symbols:
+  Global:
+    - Name:    .debug_foo
+      Type:    STT_SECTION
+      Section: .debug_foo
+    - Name:    .notdebug_foo
+      Type:    STT_SECTION
+      Section: .notdebug_foo
 ...
Index: llvm/trunk/test/tools/llvm-objcopy/ELF/compress-debug-sections-zlib-gnu.test
===================================================================
--- llvm/trunk/test/tools/llvm-objcopy/ELF/compress-debug-sections-zlib-gnu.test
+++ llvm/trunk/test/tools/llvm-objcopy/ELF/compress-debug-sections-zlib-gnu.test
@@ -57,7 +57,8 @@
 
 # CHECK-FLAGS: Relocations [
 # CHECK-FLAGS-NEXT:   .rela.debug_foo {
-# CHECK-FLAGS-NEXT:     0x1 R_X86_64_32 - 0x0
+# CHECK-FLAGS-NEXT:     0x1 R_X86_64_32 .zdebug_foo 0x0
+# CHECK-FLAGS-NEXT:     0x2 R_X86_64_32 .notdebug_foo 0x0
 # CHECK-FLAGS-NEXT:   }
 # CHECK-FLAGS-NEXT: ]
 
Index: llvm/trunk/test/tools/llvm-objcopy/ELF/compress-debug-sections-zlib.test
===================================================================
--- llvm/trunk/test/tools/llvm-objcopy/ELF/compress-debug-sections-zlib.test
+++ llvm/trunk/test/tools/llvm-objcopy/ELF/compress-debug-sections-zlib.test
@@ -57,7 +57,7 @@
 
 # CHECK-FLAGS: Relocations [
 # CHECK-FLAGS-NEXT:   .rela.debug_foo {
-# CHECK-FLAGS-NEXT:     0x1 R_X86_64_32 - 0x0
+# CHECK-FLAGS-NEXT:     0x1 R_X86_64_32 .debug_foo 0x0
+# CHECK-FLAGS-NEXT:     0x2 R_X86_64_32 .notdebug_foo 0x0
 # CHECK-FLAGS-NEXT:   }
 # CHECK-FLAGS-NEXT: ]
-
Index: llvm/trunk/tools/llvm-objcopy/ELF/ELFObjcopy.cpp
===================================================================
--- llvm/trunk/tools/llvm-objcopy/ELF/ELFObjcopy.cpp
+++ llvm/trunk/tools/llvm-objcopy/ELF/ELFObjcopy.cpp
@@ -232,27 +232,24 @@
     const CopyConfig &Config, Object &Obj, SectionPred &RemovePred,
     function_ref<bool(const SectionBase &)> shouldReplace,
     function_ref<SectionBase *(const SectionBase *)> addSection) {
+  // Build a list of the debug sections we are going to replace.
+  // We can't call `addSection` while iterating over sections,
+  // because it would mutate the sections array.
   SmallVector<SectionBase *, 13> ToReplace;
-  SmallVector<RelocationSection *, 13> RelocationSections;
-  for (auto &Sec : Obj.sections()) {
-    if (RelocationSection *R = dyn_cast<RelocationSection>(&Sec)) {
-      if (shouldReplace(*R->getSection()))
-        RelocationSections.push_back(R);
-      continue;
-    }
-
+  for (auto &Sec : Obj.sections())
     if (shouldReplace(Sec))
       ToReplace.push_back(&Sec);
-  }
-
-  for (SectionBase *S : ToReplace) {
-    SectionBase *NewSection = addSection(S);
 
-    for (RelocationSection *RS : RelocationSections) {
-      if (RS->getSection() == S)
-        RS->setSection(NewSection);
-    }
-  }
+  // Build a mapping from original section to a new one.
+  DenseMap<SectionBase *, SectionBase *> FromTo;
+  for (SectionBase *S : ToReplace)
+    FromTo[S] = addSection(S);
+
+  // Now we want to update the target sections of relocation
+  // sections. Also we will update the relocations themselves
+  // to update the symbol references.
+  for (auto &Sec : Obj.sections())
+    Sec.replaceSectionReferences(FromTo);
 
   RemovePred = [shouldReplace, RemovePred](const SectionBase &Sec) {
     return shouldReplace(Sec) || RemovePred(Sec);
Index: llvm/trunk/tools/llvm-objcopy/ELF/Object.h
===================================================================
--- llvm/trunk/tools/llvm-objcopy/ELF/Object.h
+++ llvm/trunk/tools/llvm-objcopy/ELF/Object.h
@@ -280,6 +280,8 @@
   virtual void accept(SectionVisitor &Visitor) const = 0;
   virtual void accept(MutableSectionVisitor &Visitor) = 0;
   virtual void markSymbols();
+  virtual void
+  replaceSectionReferences(const DenseMap<SectionBase *, SectionBase *> &);
 };
 
 class Segment {
@@ -596,6 +598,8 @@
       function_ref<bool(const SectionBase *)> ToRemove) override;
   Error removeSymbols(function_ref<bool(const Symbol &)> ToRemove) override;
   void markSymbols() override;
+  void replaceSectionReferences(
+      const DenseMap<SectionBase *, SectionBase *> &FromTo) override;
 
   static bool classof(const SectionBase *S) {
     if (S->Flags & ELF::SHF_ALLOC)
Index: llvm/trunk/tools/llvm-objcopy/ELF/Object.cpp
===================================================================
--- llvm/trunk/tools/llvm-objcopy/ELF/Object.cpp
+++ llvm/trunk/tools/llvm-objcopy/ELF/Object.cpp
@@ -62,6 +62,8 @@
 void SectionBase::initialize(SectionTableRef SecTable) {}
 void SectionBase::finalize() {}
 void SectionBase::markSymbols() {}
+void SectionBase::replaceSectionReferences(
+    const DenseMap<SectionBase *, SectionBase *> &) {}
 
 template <class ELFT> void ELFWriter<ELFT>::writeShdr(const SectionBase &Sec) {
   uint8_t *B = Buf.getBufferStart();
@@ -634,6 +636,19 @@
     Reloc.RelocSymbol->Referenced = true;
 }
 
+void RelocationSection::replaceSectionReferences(
+    const DenseMap<SectionBase *, SectionBase *> &FromTo) {
+  // Update the target section if it was replaced.
+  if (SectionBase *To = FromTo.lookup(SecToApplyRel))
+    SecToApplyRel = To;
+
+  // Change the sections where symbols are defined in if their
+  // original sections were replaced.
+  for (const Relocation &R : Relocations)
+    if (SectionBase *To = FromTo.lookup(R.RelocSymbol->DefinedIn))
+      R.RelocSymbol->DefinedIn = To;
+}
+
 void SectionWriter::visit(const DynamicRelocationSection &Sec) {
   llvm::copy(Sec.Contents,
             Out.getBufferStart() + Sec.Offset);