Index: lld/trunk/ELF/OutputSections.h
===================================================================
--- lld/trunk/ELF/OutputSections.h
+++ lld/trunk/ELF/OutputSections.h
@@ -11,7 +11,6 @@
 #define LLD_ELF_OUTPUT_SECTIONS_H
 
 #include "Config.h"
-#include "GdbIndex.h"
 #include "Relocations.h"
 
 #include "lld/Core/LLVM.h"
@@ -105,30 +104,6 @@
   uint32_t Link = 0;
 };
 
-template <class ELFT> class GdbIndexSection final : public OutputSectionBase {
-  typedef typename ELFT::uint uintX_t;
-
-  const unsigned OffsetTypeSize = 4;
-  const unsigned CuListOffset = 6 * OffsetTypeSize;
-  const unsigned CompilationUnitSize = 16;
-  const unsigned AddressEntrySize = 16 + OffsetTypeSize;
-  const unsigned SymTabEntrySize = 2 * OffsetTypeSize;
-
-public:
-  GdbIndexSection();
-  void finalize() override;
-  void writeTo(uint8_t *Buf) override;
-
-  // Pairs of [CU Offset, CU length].
-  std::vector<std::pair<uintX_t, uintX_t>> CompilationUnits;
-
-private:
-  void parseDebugSections();
-  void readDwarf(InputSection<ELFT> *I);
-
-  uint32_t CuTypesOffset;
-};
-
 // For more information about .gnu.version and .gnu.version_r see:
 // https://www.akkadia.org/drepper/symbol-versioning
 
@@ -338,7 +313,6 @@
   static uint8_t First;
   static EhFrameHeader<ELFT> *EhFrameHdr;
   static EhOutputSection<ELFT> *EhFrame;
-  static GdbIndexSection<ELFT> *GdbIndex;
   static OutputSection<ELFT> *Bss;
   static OutputSection<ELFT> *MipsRldMap;
   static OutputSectionBase *Opd;
@@ -391,7 +365,6 @@
 template <class ELFT> uint8_t Out<ELFT>::First;
 template <class ELFT> EhFrameHeader<ELFT> *Out<ELFT>::EhFrameHdr;
 template <class ELFT> EhOutputSection<ELFT> *Out<ELFT>::EhFrame;
-template <class ELFT> GdbIndexSection<ELFT> *Out<ELFT>::GdbIndex;
 template <class ELFT> OutputSection<ELFT> *Out<ELFT>::Bss;
 template <class ELFT> OutputSection<ELFT> *Out<ELFT>::MipsRldMap;
 template <class ELFT> OutputSectionBase *Out<ELFT>::Opd;
Index: lld/trunk/ELF/OutputSections.cpp
===================================================================
--- lld/trunk/ELF/OutputSections.cpp
+++ lld/trunk/ELF/OutputSections.cpp
@@ -10,7 +10,6 @@
 #include "OutputSections.h"
 #include "Config.h"
 #include "EhFrame.h"
-#include "GdbIndex.h"
 #include "LinkerScript.h"
 #include "Memory.h"
 #include "Strings.h"
@@ -63,50 +62,6 @@
   Shdr->sh_name = ShName;
 }
 
-template <class ELFT>
-GdbIndexSection<ELFT>::GdbIndexSection()
-    : OutputSectionBase(".gdb_index", SHT_PROGBITS, 0) {}
-
-template <class ELFT> void GdbIndexSection<ELFT>::parseDebugSections() {
-  std::vector<InputSection<ELFT> *> &IS =
-      static_cast<OutputSection<ELFT> *>(Out<ELFT>::DebugInfo)->Sections;
-
-  for (InputSection<ELFT> *I : IS)
-    readDwarf(I);
-}
-
-template <class ELFT>
-void GdbIndexSection<ELFT>::readDwarf(InputSection<ELFT> *I) {
-  std::vector<std::pair<uintX_t, uintX_t>> CuList = readCuList(I);
-  CompilationUnits.insert(CompilationUnits.end(), CuList.begin(), CuList.end());
-}
-
-template <class ELFT> void GdbIndexSection<ELFT>::finalize() {
-  parseDebugSections();
-
-  // GdbIndex header consist from version fields
-  // and 5 more fields with different kinds of offsets.
-  CuTypesOffset = CuListOffset + CompilationUnits.size() * CompilationUnitSize;
-  this->Size = CuTypesOffset;
-}
-
-template <class ELFT> void GdbIndexSection<ELFT>::writeTo(uint8_t *Buf) {
-  write32le(Buf, 7);                  // Write Version
-  write32le(Buf + 4, CuListOffset);   // CU list offset
-  write32le(Buf + 8, CuTypesOffset);  // Types CU list offset
-  write32le(Buf + 12, CuTypesOffset); // Address area offset
-  write32le(Buf + 16, CuTypesOffset); // Symbol table offset
-  write32le(Buf + 20, CuTypesOffset); // Constant pool offset
-  Buf += 24;
-
-  // Write the CU list.
-  for (std::pair<uintX_t, uintX_t> CU : CompilationUnits) {
-    write64le(Buf, CU.first);
-    write64le(Buf + 8, CU.second);
-    Buf += 16;
-  }
-}
-
 // Returns the number of version definition entries. Because the first entry
 // is for the version definition itself, it is the number of versioned symbols
 // plus one. Note that we don't support multiple versions yet.
@@ -908,11 +863,6 @@
 template class VersionDefinitionSection<ELF64LE>;
 template class VersionDefinitionSection<ELF64BE>;
 
-template class GdbIndexSection<ELF32LE>;
-template class GdbIndexSection<ELF32BE>;
-template class GdbIndexSection<ELF64LE>;
-template class GdbIndexSection<ELF64BE>;
-
 template class OutputSectionFactory<ELF32LE>;
 template class OutputSectionFactory<ELF32BE>;
 template class OutputSectionFactory<ELF64LE>;
Index: lld/trunk/ELF/SyntheticSections.h
===================================================================
--- lld/trunk/ELF/SyntheticSections.h
+++ lld/trunk/ELF/SyntheticSections.h
@@ -10,6 +10,7 @@
 #ifndef LLD_ELF_SYNTHETIC_SECTION_H
 #define LLD_ELF_SYNTHETIC_SECTION_H
 
+#include "GdbIndex.h"
 #include "InputSection.h"
 #include "llvm/ADT/SmallPtrSet.h"
 
@@ -502,6 +503,32 @@
   std::vector<std::pair<const SymbolBody *, unsigned>> Entries;
 };
 
+template <class ELFT>
+class GdbIndexSection final : public SyntheticSection<ELFT> {
+  typedef typename ELFT::uint uintX_t;
+
+  const unsigned OffsetTypeSize = 4;
+  const unsigned CuListOffset = 6 * OffsetTypeSize;
+  const unsigned CompilationUnitSize = 16;
+  const unsigned AddressEntrySize = 16 + OffsetTypeSize;
+  const unsigned SymTabEntrySize = 2 * OffsetTypeSize;
+
+public:
+  GdbIndexSection();
+  void finalize() override;
+  void writeTo(uint8_t *Buf) override;
+  size_t getSize() const override { return CuTypesOffset; }
+
+  // Pairs of [CU Offset, CU length].
+  std::vector<std::pair<uintX_t, uintX_t>> CompilationUnits;
+
+private:
+  void parseDebugSections();
+  void readDwarf(InputSection<ELFT> *I);
+
+  uint32_t CuTypesOffset;
+};
+
 template <class ELFT> InputSection<ELFT> *createCommonSection();
 template <class ELFT> InputSection<ELFT> *createInterpSection();
 template <class ELFT> MergeInputSection<ELFT> *createCommentSection();
@@ -514,6 +541,7 @@
   static StringTableSection<ELFT> *DynStrTab;
   static SymbolTableSection<ELFT> *DynSymTab;
   static GnuHashTableSection<ELFT> *GnuHashTab;
+  static GdbIndexSection<ELFT> *GdbIndex;
   static GotSection<ELFT> *Got;
   static MipsGotSection<ELFT> *MipsGot;
   static GotPltSection<ELFT> *GotPlt;
@@ -535,6 +563,7 @@
 template <class ELFT> DynamicSection<ELFT> *In<ELFT>::Dynamic;
 template <class ELFT> StringTableSection<ELFT> *In<ELFT>::DynStrTab;
 template <class ELFT> SymbolTableSection<ELFT> *In<ELFT>::DynSymTab;
+template <class ELFT> GdbIndexSection<ELFT> *In<ELFT>::GdbIndex;
 template <class ELFT> GnuHashTableSection<ELFT> *In<ELFT>::GnuHashTab;
 template <class ELFT> GotSection<ELFT> *In<ELFT>::Got;
 template <class ELFT> MipsGotSection<ELFT> *In<ELFT>::MipsGot;
Index: lld/trunk/ELF/SyntheticSections.cpp
===================================================================
--- lld/trunk/ELF/SyntheticSections.cpp
+++ lld/trunk/ELF/SyntheticSections.cpp
@@ -1360,6 +1360,49 @@
   return Target->PltHeaderSize + Entries.size() * Target->PltEntrySize;
 }
 
+template <class ELFT>
+GdbIndexSection<ELFT>::GdbIndexSection()
+    : SyntheticSection<ELFT>(0, SHT_PROGBITS, 1, ".gdb_index") {}
+
+template <class ELFT> void GdbIndexSection<ELFT>::parseDebugSections() {
+  std::vector<InputSection<ELFT> *> &IS =
+      static_cast<OutputSection<ELFT> *>(Out<ELFT>::DebugInfo)->Sections;
+
+  for (InputSection<ELFT> *I : IS)
+    readDwarf(I);
+}
+
+template <class ELFT>
+void GdbIndexSection<ELFT>::readDwarf(InputSection<ELFT> *I) {
+  std::vector<std::pair<uintX_t, uintX_t>> CuList = readCuList(I);
+  CompilationUnits.insert(CompilationUnits.end(), CuList.begin(), CuList.end());
+}
+
+template <class ELFT> void GdbIndexSection<ELFT>::finalize() {
+  parseDebugSections();
+
+  // GdbIndex header consist from version fields
+  // and 5 more fields with different kinds of offsets.
+  CuTypesOffset = CuListOffset + CompilationUnits.size() * CompilationUnitSize;
+}
+
+template <class ELFT> void GdbIndexSection<ELFT>::writeTo(uint8_t *Buf) {
+  write32le(Buf, 7);                  // Write Version
+  write32le(Buf + 4, CuListOffset);   // CU list offset
+  write32le(Buf + 8, CuTypesOffset);  // Types CU list offset
+  write32le(Buf + 12, CuTypesOffset); // Address area offset
+  write32le(Buf + 16, CuTypesOffset); // Symbol table offset
+  write32le(Buf + 20, CuTypesOffset); // Constant pool offset
+  Buf += 24;
+
+  // Write the CU list.
+  for (std::pair<uintX_t, uintX_t> CU : CompilationUnits) {
+    write64le(Buf, CU.first);
+    write64le(Buf + 8, CU.second);
+    Buf += 16;
+  }
+}
+
 template InputSection<ELF32LE> *elf::createCommonSection();
 template InputSection<ELF32BE> *elf::createCommonSection();
 template InputSection<ELF64LE> *elf::createCommonSection();
@@ -1469,3 +1512,8 @@
 template class elf::PltSection<ELF32BE>;
 template class elf::PltSection<ELF64LE>;
 template class elf::PltSection<ELF64BE>;
+
+template class elf::GdbIndexSection<ELF32LE>;
+template class elf::GdbIndexSection<ELF32BE>;
+template class elf::GdbIndexSection<ELF64LE>;
+template class elf::GdbIndexSection<ELF64BE>;
Index: lld/trunk/ELF/Writer.cpp
===================================================================
--- lld/trunk/ELF/Writer.cpp
+++ lld/trunk/ELF/Writer.cpp
@@ -268,7 +268,7 @@
   if (Config->SysvHash)
     In<ELFT>::HashTab = make<HashTableSection<ELFT>>();
   if (Config->GdbIndex)
-    Out<ELFT>::GdbIndex = make<GdbIndexSection<ELFT>>();
+    In<ELFT>::GdbIndex = make<GdbIndexSection<ELFT>>();
 
   In<ELFT>::RelaPlt = make<RelocationSection<ELFT>>(
       Config->Rela ? ".rela.plt" : ".rel.plt", false /*Sort*/);
@@ -979,8 +979,9 @@
   finalizeSynthetic<ELFT>(
       {In<ELFT>::DynSymTab, In<ELFT>::GnuHashTab, In<ELFT>::HashTab,
        In<ELFT>::SymTab, In<ELFT>::ShStrTab, In<ELFT>::StrTab,
-       In<ELFT>::DynStrTab, In<ELFT>::Got, In<ELFT>::MipsGot, In<ELFT>::GotPlt,
-       In<ELFT>::RelaDyn, In<ELFT>::RelaPlt, In<ELFT>::Plt, In<ELFT>::Dynamic});
+       In<ELFT>::DynStrTab, In<ELFT>::GdbIndex, In<ELFT>::Got,
+       In<ELFT>::MipsGot, In<ELFT>::GotPlt, In<ELFT>::RelaDyn,
+       In<ELFT>::RelaPlt, In<ELFT>::Plt, In<ELFT>::Dynamic});
 }
 
 template <class ELFT> bool Writer<ELFT>::needsGot() {
@@ -1006,8 +1007,8 @@
 
   // This order is not the same as the final output order
   // because we sort the sections using their attributes below.
-  if (Out<ELFT>::GdbIndex && Out<ELFT>::DebugInfo)
-    Add(Out<ELFT>::GdbIndex);
+  if (In<ELFT>::GdbIndex && Out<ELFT>::DebugInfo)
+    addInputSec(In<ELFT>::GdbIndex);
   addInputSec(In<ELFT>::SymTab);
   addInputSec(In<ELFT>::ShStrTab);
   addInputSec(In<ELFT>::StrTab);