From ff23d3e741ee9d7f7f1bd4a5cb0ff43b8b76389b Mon Sep 17 00:00:00 2001
From: Eugene Leviant <eleviant@accesssoftek.com>
Date: Fri, 18 Nov 2016 14:35:03 +0000
Subject: [PATCH] [ELF] Convert PltSection to input section

Differential revision: https://reviews.llvm.org/D26842

llvm-svn: 287346
---
 lld/ELF/OutputSections.cpp    | 37 -------------------------------------
 lld/ELF/OutputSections.h      | 21 ---------------------
 lld/ELF/Relocations.cpp       |  2 +-
 lld/ELF/Symbols.cpp           |  2 +-
 lld/ELF/SyntheticSections.cpp | 36 ++++++++++++++++++++++++++++++++++++
 lld/ELF/SyntheticSections.h   | 14 ++++++++++++++
 lld/ELF/Target.cpp            | 12 ++++++------
 lld/ELF/Writer.cpp            |  8 ++++----
 8 files changed, 62 insertions(+), 70 deletions(-)

diff --git a/lld/ELF/OutputSections.cpp b/lld/ELF/OutputSections.cpp
index 2119882..cdbe628 100644
--- a/lld/ELF/OutputSections.cpp
+++ b/lld/ELF/OutputSections.cpp
@@ -108,38 +108,6 @@ template <class ELFT> void GdbIndexSection<ELFT>::writeTo(uint8_t *Buf) {
   }
 }
 
-template <class ELFT>
-PltSection<ELFT>::PltSection()
-    : OutputSectionBase(".plt", SHT_PROGBITS, SHF_ALLOC | SHF_EXECINSTR) {
-  this->Addralign = 16;
-}
-
-template <class ELFT> void PltSection<ELFT>::writeTo(uint8_t *Buf) {
-  // At beginning of PLT, we have code to call the dynamic linker
-  // to resolve dynsyms at runtime. Write such code.
-  Target->writePltHeader(Buf);
-  size_t Off = Target->PltHeaderSize;
-
-  for (auto &I : Entries) {
-    const SymbolBody *B = I.first;
-    unsigned RelOff = I.second;
-    uint64_t Got = B->getGotPltVA<ELFT>();
-    uint64_t Plt = this->Addr + Off;
-    Target->writePlt(Buf + Off, Got, Plt, B->PltIndex, RelOff);
-    Off += Target->PltEntrySize;
-  }
-}
-
-template <class ELFT> void PltSection<ELFT>::addEntry(SymbolBody &Sym) {
-  Sym.PltIndex = Entries.size();
-  unsigned RelOff = In<ELFT>::RelaPlt->getRelocOffset();
-  Entries.push_back(std::make_pair(&Sym, RelOff));
-}
-
-template <class ELFT> void PltSection<ELFT>::finalize() {
-  this->Size = Target->PltHeaderSize + Entries.size() * Target->PltEntrySize;
-}
-
 // 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.
@@ -894,11 +862,6 @@ template class EhFrameHeader<ELF32BE>;
 template class EhFrameHeader<ELF64LE>;
 template class EhFrameHeader<ELF64BE>;
 
-template class PltSection<ELF32LE>;
-template class PltSection<ELF32BE>;
-template class PltSection<ELF64LE>;
-template class PltSection<ELF64BE>;
-
 template class OutputSection<ELF32LE>;
 template class OutputSection<ELF32BE>;
 template class OutputSection<ELF64LE>;
diff --git a/lld/ELF/OutputSections.h b/lld/ELF/OutputSections.h
index df4707a..0c1c027 100644
--- a/lld/ELF/OutputSections.h
+++ b/lld/ELF/OutputSections.h
@@ -45,7 +45,6 @@ public:
     EHFrame,
     EHFrameHdr,
     Merge,
-    Plt,
     Regular,
     VersDef,
     VersNeed,
@@ -130,24 +129,6 @@ private:
   uint32_t CuTypesOffset;
 };
 
-template <class ELFT> class PltSection final : public OutputSectionBase {
-  typedef typename ELFT::uint uintX_t;
-
-public:
-  PltSection();
-  void finalize() override;
-  void writeTo(uint8_t *Buf) override;
-  void addEntry(SymbolBody &Sym);
-  bool empty() const { return Entries.empty(); }
-  Kind getKind() const override { return Plt; }
-  static bool classof(const OutputSectionBase *B) {
-    return B->getKind() == Plt;
-  }
-
-private:
-  std::vector<std::pair<const SymbolBody *, unsigned>> Entries;
-};
-
 // For more information about .gnu.version and .gnu.version_r see:
 // https://www.akkadia.org/drepper/symbol-versioning
 
@@ -362,7 +343,6 @@ template <class ELFT> struct Out {
   static OutputSection<ELFT> *MipsRldMap;
   static OutputSectionBase *Opd;
   static uint8_t *OpdBuf;
-  static PltSection<ELFT> *Plt;
   static VersionDefinitionSection<ELFT> *VerDef;
   static VersionTableSection<ELFT> *VerSym;
   static VersionNeedSection<ELFT> *VerNeed;
@@ -416,7 +396,6 @@ template <class ELFT> OutputSection<ELFT> *Out<ELFT>::Bss;
 template <class ELFT> OutputSection<ELFT> *Out<ELFT>::MipsRldMap;
 template <class ELFT> OutputSectionBase *Out<ELFT>::Opd;
 template <class ELFT> uint8_t *Out<ELFT>::OpdBuf;
-template <class ELFT> PltSection<ELFT> *Out<ELFT>::Plt;
 template <class ELFT> VersionDefinitionSection<ELFT> *Out<ELFT>::VerDef;
 template <class ELFT> VersionTableSection<ELFT> *Out<ELFT>::VerSym;
 template <class ELFT> VersionNeedSection<ELFT> *Out<ELFT>::VerNeed;
diff --git a/lld/ELF/Relocations.cpp b/lld/ELF/Relocations.cpp
index c402bce..8bcf4d2 100644
--- a/lld/ELF/Relocations.cpp
+++ b/lld/ELF/Relocations.cpp
@@ -743,7 +743,7 @@ static void scanRelocs(InputSectionBase<ELFT> &C, ArrayRef<RelTy> Rels) {
     if (needsPlt(Expr)) {
       if (Body.isInPlt())
         continue;
-      Out<ELFT>::Plt->addEntry(Body);
+      In<ELFT>::Plt->addEntry(Body);
 
       uint32_t Rel;
       if (Body.isGnuIFunc() && !Preemptible)
diff --git a/lld/ELF/Symbols.cpp b/lld/ELF/Symbols.cpp
index 89053d1..255bd32 100644
--- a/lld/ELF/Symbols.cpp
+++ b/lld/ELF/Symbols.cpp
@@ -167,7 +167,7 @@ template <class ELFT> typename ELFT::uint SymbolBody::getGotPltOffset() const {
 }
 
 template <class ELFT> typename ELFT::uint SymbolBody::getPltVA() const {
-  return Out<ELFT>::Plt->Addr + Target->PltHeaderSize +
+  return In<ELFT>::Plt->getVA() + Target->PltHeaderSize +
          PltIndex * Target->PltEntrySize;
 }
 
diff --git a/lld/ELF/SyntheticSections.cpp b/lld/ELF/SyntheticSections.cpp
index c6c4b75..8f66ade0 100644
--- a/lld/ELF/SyntheticSections.cpp
+++ b/lld/ELF/SyntheticSections.cpp
@@ -1329,6 +1329,37 @@ template <class ELFT> void HashTableSection<ELFT>::writeTo(uint8_t *Buf) {
   }
 }
 
+template <class ELFT>
+PltSection<ELFT>::PltSection()
+    : SyntheticSection<ELFT>(SHF_ALLOC | SHF_EXECINSTR, SHT_PROGBITS, 16,
+                             ".plt") {}
+
+template <class ELFT> void PltSection<ELFT>::writeTo(uint8_t *Buf) {
+  // At beginning of PLT, we have code to call the dynamic linker
+  // to resolve dynsyms at runtime. Write such code.
+  Target->writePltHeader(Buf);
+  size_t Off = Target->PltHeaderSize;
+
+  for (auto &I : Entries) {
+    const SymbolBody *B = I.first;
+    unsigned RelOff = I.second;
+    uint64_t Got = B->getGotPltVA<ELFT>();
+    uint64_t Plt = this->getVA() + Off;
+    Target->writePlt(Buf + Off, Got, Plt, B->PltIndex, RelOff);
+    Off += Target->PltEntrySize;
+  }
+}
+
+template <class ELFT> void PltSection<ELFT>::addEntry(SymbolBody &Sym) {
+  Sym.PltIndex = Entries.size();
+  unsigned RelOff = In<ELFT>::RelaPlt->getRelocOffset();
+  Entries.push_back(std::make_pair(&Sym, RelOff));
+}
+
+template <class ELFT> size_t PltSection<ELFT>::getSize() const {
+  return Target->PltHeaderSize + Entries.size() * Target->PltEntrySize;
+}
+
 template InputSection<ELF32LE> *elf::createCommonSection();
 template InputSection<ELF32BE> *elf::createCommonSection();
 template InputSection<ELF64LE> *elf::createCommonSection();
@@ -1433,3 +1464,8 @@ template class elf::HashTableSection<ELF32LE>;
 template class elf::HashTableSection<ELF32BE>;
 template class elf::HashTableSection<ELF64LE>;
 template class elf::HashTableSection<ELF64BE>;
+
+template class elf::PltSection<ELF32LE>;
+template class elf::PltSection<ELF32BE>;
+template class elf::PltSection<ELF64LE>;
+template class elf::PltSection<ELF64BE>;
diff --git a/lld/ELF/SyntheticSections.h b/lld/ELF/SyntheticSections.h
index e3e927a9..e441f99 100644
--- a/lld/ELF/SyntheticSections.h
+++ b/lld/ELF/SyntheticSections.h
@@ -490,6 +490,18 @@ private:
   size_t Size = 0;
 };
 
+template <class ELFT> class PltSection final : public SyntheticSection<ELFT> {
+public:
+  PltSection();
+  void writeTo(uint8_t *Buf) override;
+  size_t getSize() const override;
+  void addEntry(SymbolBody &Sym);
+  bool empty() const { return Entries.empty(); }
+
+private:
+  std::vector<std::pair<const SymbolBody *, unsigned>> Entries;
+};
+
 template <class ELFT> InputSection<ELFT> *createCommonSection();
 template <class ELFT> InputSection<ELFT> *createInterpSection();
 template <class ELFT> MergeInputSection<ELFT> *createCommentSection();
@@ -510,6 +522,7 @@ template <class ELFT> struct In {
   static MipsAbiFlagsSection<ELFT> *MipsAbiFlags;
   static MipsOptionsSection<ELFT> *MipsOptions;
   static MipsReginfoSection<ELFT> *MipsReginfo;
+  static PltSection<ELFT> *Plt;
   static RelocationSection<ELFT> *RelaDyn;
   static RelocationSection<ELFT> *RelaPlt;
   static StringTableSection<ELFT> *ShStrTab;
@@ -531,6 +544,7 @@ template <class ELFT> InputSection<ELFT> *In<ELFT>::Interp;
 template <class ELFT> MipsAbiFlagsSection<ELFT> *In<ELFT>::MipsAbiFlags;
 template <class ELFT> MipsOptionsSection<ELFT> *In<ELFT>::MipsOptions;
 template <class ELFT> MipsReginfoSection<ELFT> *In<ELFT>::MipsReginfo;
+template <class ELFT> PltSection<ELFT> *In<ELFT>::Plt;
 template <class ELFT> RelocationSection<ELFT> *In<ELFT>::RelaDyn;
 template <class ELFT> RelocationSection<ELFT> *In<ELFT>::RelaPlt;
 template <class ELFT> StringTableSection<ELFT> *In<ELFT>::ShStrTab;
diff --git a/lld/ELF/Target.cpp b/lld/ELF/Target.cpp
index 3ad2316..bcada08 100644
--- a/lld/ELF/Target.cpp
+++ b/lld/ELF/Target.cpp
@@ -615,7 +615,7 @@ void X86_64TargetInfo<ELFT>::writePltHeader(uint8_t *Buf) const {
   };
   memcpy(Buf, PltData, sizeof(PltData));
   uint64_t Got = In<ELFT>::GotPlt->getVA();
-  uint64_t Plt = Out<ELFT>::Plt->Addr;
+  uint64_t Plt = In<ELFT>::Plt->getVA();
   write32le(Buf + 2, Got - Plt + 2); // GOT+8
   write32le(Buf + 8, Got - Plt + 4); // GOT+16
 }
@@ -1255,7 +1255,7 @@ uint32_t AArch64TargetInfo::getDynRel(uint32_t Type) const {
 }
 
 void AArch64TargetInfo::writeGotPlt(uint8_t *Buf, const SymbolBody &) const {
-  write64le(Buf, Out<ELF64LE>::Plt->Addr);
+  write64le(Buf, In<ELF64LE>::Plt->getVA());
 }
 
 static uint64_t getAArch64Page(uint64_t Expr) {
@@ -1276,7 +1276,7 @@ void AArch64TargetInfo::writePltHeader(uint8_t *Buf) const {
   memcpy(Buf, PltData, sizeof(PltData));
 
   uint64_t Got = In<ELF64LE>::GotPlt->getVA();
-  uint64_t Plt = Out<ELF64LE>::Plt->Addr;
+  uint64_t Plt = In<ELF64LE>::Plt->getVA();
   relocateOne(Buf + 4, R_AARCH64_ADR_PREL_PG_HI21,
               getAArch64Page(Got + 16) - getAArch64Page(Plt + 4));
   relocateOne(Buf + 8, R_AARCH64_LDST64_ABS_LO12_NC, Got + 16);
@@ -1617,7 +1617,7 @@ uint32_t ARMTargetInfo::getDynRel(uint32_t Type) const {
 }
 
 void ARMTargetInfo::writeGotPlt(uint8_t *Buf, const SymbolBody &) const {
-  write32le(Buf, Out<ELF32LE>::Plt->Addr);
+  write32le(Buf, In<ELF32LE>::Plt->getVA());
 }
 
 void ARMTargetInfo::writePltHeader(uint8_t *Buf) const {
@@ -1630,7 +1630,7 @@ void ARMTargetInfo::writePltHeader(uint8_t *Buf) const {
   };
   memcpy(Buf, PltData, sizeof(PltData));
   uint64_t GotPlt = In<ELF32LE>::GotPlt->getVA();
-  uint64_t L1 = Out<ELF32LE>::Plt->Addr + 8;
+  uint64_t L1 = In<ELF32LE>::Plt->getVA() + 8;
   write32le(Buf + 16, GotPlt - L1 - 8);
 }
 
@@ -1997,7 +1997,7 @@ bool MipsTargetInfo<ELFT>::isTlsGlobalDynamicRel(uint32_t Type) const {
 
 template <class ELFT>
 void MipsTargetInfo<ELFT>::writeGotPlt(uint8_t *Buf, const SymbolBody &) const {
-  write32<ELFT::TargetEndianness>(Buf, Out<ELFT>::Plt->Addr);
+  write32<ELFT::TargetEndianness>(Buf, In<ELFT>::Plt->getVA());
 }
 
 template <endianness E, uint8_t BSIZE, uint8_t SHIFT>
diff --git a/lld/ELF/Writer.cpp b/lld/ELF/Writer.cpp
index e740183..35a792a 100644
--- a/lld/ELF/Writer.cpp
+++ b/lld/ELF/Writer.cpp
@@ -212,7 +212,7 @@ template <class ELFT> void Writer<ELFT>::createSyntheticSections() {
   In<ELFT>::DynStrTab = make<StringTableSection<ELFT>>(".dynstr", true);
   In<ELFT>::Dynamic = make<DynamicSection<ELFT>>();
   Out<ELFT>::EhFrame = make<EhOutputSection<ELFT>>();
-  Out<ELFT>::Plt = make<PltSection<ELFT>>();
+  In<ELFT>::Plt = make<PltSection<ELFT>>();
   In<ELFT>::RelaDyn = make<RelocationSection<ELFT>>(
       Config->Rela ? ".rela.dyn" : ".rel.dyn", Config->ZCombreloc);
   In<ELFT>::ShStrTab = make<StringTableSection<ELFT>>(".shstrtab", false);
@@ -955,7 +955,7 @@ template <class ELFT> void Writer<ELFT>::finalizeSections() {
       {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>::Dynamic});
+       In<ELFT>::RelaDyn, In<ELFT>::RelaPlt, In<ELFT>::Plt, In<ELFT>::Dynamic});
 }
 
 template <class ELFT> bool Writer<ELFT>::needsGot() {
@@ -1022,8 +1022,8 @@ template <class ELFT> void Writer<ELFT>::addPredefinedSections() {
   if (!In<ELFT>::GotPlt->empty())
     addInputSec(In<ELFT>::GotPlt);
 
-  if (!Out<ELFT>::Plt->empty())
-    Add(Out<ELFT>::Plt);
+  if (!In<ELFT>::Plt->empty())
+    addInputSec(In<ELFT>::Plt);
   if (!Out<ELFT>::EhFrame->empty())
     Add(Out<ELFT>::EhFrameHdr);
   if (Out<ELFT>::Bss->Size > 0)
-- 
2.7.4