From 7b3dd1789c52a24b16804e1b1981adde6e5aa43e Mon Sep 17 00:00:00 2001
From: Simon Atanasyan <simon@atanasyan.com>
Date: Wed, 28 May 2014 04:10:01 +0000
Subject: [PATCH] [Mips] Do not mix _gp and _gp_disp symbols in relocation
 handling.

No functional changes.

llvm-svn: 209709
---
 .../ELF/Mips/MipsRelocationHandler.cpp             |  9 ++++----
 lld/lib/ReaderWriter/ELF/Mips/MipsTargetHandler.h  | 27 ++++++++++++++--------
 2 files changed, 22 insertions(+), 14 deletions(-)

diff --git a/lld/lib/ReaderWriter/ELF/Mips/MipsRelocationHandler.cpp b/lld/lib/ReaderWriter/ELF/Mips/MipsRelocationHandler.cpp
index 73d47c7..ce92041 100644
--- a/lld/lib/ReaderWriter/ELF/Mips/MipsRelocationHandler.cpp
+++ b/lld/lib/ReaderWriter/ELF/Mips/MipsRelocationHandler.cpp
@@ -129,6 +129,9 @@ error_code MipsTargetRelocationHandler::applyRelocation(
   AtomLayout *gpAtom = _mipsTargetLayout.getGP();
   uint64_t gpAddr = gpAtom ? gpAtom->_virtualAddr : 0;
 
+  AtomLayout *gpDispAtom = _mipsTargetLayout.getGPDisp();
+  bool isGpDisp = gpDispAtom && ref.target() == gpDispAtom->_atom;
+
   uint8_t *atomContent = buf.getBufferStart() + atom._fileOffset;
   uint8_t *location = atomContent + ref.offsetInAtom();
   uint64_t targetVAddress = writer.addressOfAtom(ref.target());
@@ -144,12 +147,10 @@ error_code MipsTargetRelocationHandler::applyRelocation(
     reloc26loc(location, relocVAddress, targetVAddress, ref.addend());
     break;
   case R_MIPS_HI16:
-    relocHi16(location, relocVAddress, targetVAddress, ref.addend(),
-              ref.target() == gpAtom->_atom);
+    relocHi16(location, relocVAddress, targetVAddress, ref.addend(), isGpDisp);
     break;
   case R_MIPS_LO16:
-    relocLo16(location, relocVAddress, targetVAddress, ref.addend(),
-              ref.target() == gpAtom->_atom);
+    relocLo16(location, relocVAddress, targetVAddress, ref.addend(), isGpDisp);
     break;
   case R_MIPS_GOT16:
     relocGOT(location, relocVAddress, targetVAddress, ref.addend(), gpAddr);
diff --git a/lld/lib/ReaderWriter/ELF/Mips/MipsTargetHandler.h b/lld/lib/ReaderWriter/ELF/Mips/MipsTargetHandler.h
index 1e8253a..b2eb496 100644
--- a/lld/lib/ReaderWriter/ELF/Mips/MipsTargetHandler.h
+++ b/lld/lib/ReaderWriter/ELF/Mips/MipsTargetHandler.h
@@ -26,8 +26,7 @@ public:
   MipsTargetLayout(const MipsLinkingContext &ctx)
       : TargetLayout<ELFType>(ctx),
         _gotSection(new (_alloc) MipsGOTSection<ELFType>(ctx)),
-        _pltSection(new (_alloc) MipsPLTSection<ELFType>(ctx)),
-        _cachedGP(false) {}
+        _pltSection(new (_alloc) MipsPLTSection<ELFType>(ctx)) {}
 
   const MipsGOTSection<ELFType> &getGOTSection() const { return *_gotSection; }
   const MipsPLTSection<ELFType> &getPLTSection() const { return *_pltSection; }
@@ -47,22 +46,30 @@ public:
   /// \brief GP offset relative to .got section.
   uint64_t getGPOffset() const { return 0x7FF0; }
 
-  /// \brief Get the cached value of the GP atom.
+  /// \brief Get '_gp' symbol atom layout.
   AtomLayout *getGP() {
-    if (!_cachedGP) {
-      auto gpAtomIter = this->findAbsoluteAtom("_gp_disp");
-      _gp = *(gpAtomIter);
-      _cachedGP = true;
+    if (!_gpAtom.hasValue()) {
+      auto atom = this->findAbsoluteAtom("_gp");
+      _gpAtom = atom != this->absoluteAtoms().end() ? *atom : nullptr;
     }
-    return _gp;
+    return *_gpAtom;
+  }
+
+  /// \brief Get '_gp_disp' symbol atom layout.
+  AtomLayout *getGPDisp() {
+    if (!_gpDispAtom.hasValue()) {
+      auto atom = this->findAbsoluteAtom("_gp_disp");
+      _gpDispAtom = atom != this->absoluteAtoms().end() ? *atom : nullptr;
+    }
+    return *_gpDispAtom;
   }
 
 private:
   llvm::BumpPtrAllocator _alloc;
   MipsGOTSection<ELFType> *_gotSection;
   MipsPLTSection<ELFType> *_pltSection;
-  AtomLayout *_gp;
-  bool _cachedGP;
+  llvm::Optional<AtomLayout *> _gpAtom;
+  llvm::Optional<AtomLayout *> _gpDispAtom;
 };
 
 /// \brief Mips Runtime file.
-- 
2.7.4