[llvm] r228886 - Create the Seciton -> Rel Section map when it is first needed. NFC.

[Rafael Espindola]

Author: rafael
Date: Wed Feb 11 17:17:48 2015
New Revision: 228886

URL: http://llvm.org/viewvc/llvm-project?rev=228886&view=rev
Log:
Create the Seciton -> Rel Section map when it is first needed. NFC.

Saves a walk over every section.

Modified:
    llvm/trunk/lib/MC/ELFObjectWriter.cpp

Modified: llvm/trunk/lib/MC/ELFObjectWriter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/ELFObjectWriter.cpp?rev=228886&r1=228885&r2=228886&view=diff
==============================================================================
--- llvm/trunk/lib/MC/ELFObjectWriter.cpp (original)
+++ llvm/trunk/lib/MC/ELFObjectWriter.cpp Wed Feb 11 17:17:48 2015
@@ -247,11 +247,12 @@ class ELFObjectWriter : public MCObjectW
                             const RevGroupMapTy &RevGroupMap,
                             unsigned NumRegularSections);
 
-    void ComputeIndexMap(MCAssembler &Asm,
+    void computeIndexMap(MCAssembler &Asm,
                          SectionIndexMapTy &SectionIndexMap,
-                         const RelMapTy &RelMap);
+                         RelMapTy &RelMap);
 
-    void CreateRelocationSections(MCAssembler &Asm, RelMapTy &RelMap);
+    MCSectionData *createRelocationSection(MCAssembler &Asm,
+                                           const MCSectionData &SD);
 
     void CompressDebugSections(MCAssembler &Asm, MCAsmLayout &Layout);
 
@@ -263,11 +264,11 @@ class ELFObjectWriter : public MCObjectW
 
     // Create the sections that show up in the symbol table. Currently
     // those are the .note.GNU-stack section and the group sections.
-    void CreateIndexedSections(MCAssembler &Asm, MCAsmLayout &Layout,
+    void createIndexedSections(MCAssembler &Asm, MCAsmLayout &Layout,
                                GroupMapTy &GroupMap,
                                RevGroupMapTy &RevGroupMap,
                                SectionIndexMapTy &SectionIndexMap,
-                               const RelMapTy &RelMap);
+                               RelMapTy &RelMap);
 
     void ExecutePostLayoutBinding(MCAssembler &Asm,
                                   const MCAsmLayout &Layout) override;
@@ -941,9 +942,9 @@ bool ELFObjectWriter::isLocal(const MCSy
   return true;
 }
 
-void ELFObjectWriter::ComputeIndexMap(MCAssembler &Asm,
+void ELFObjectWriter::computeIndexMap(MCAssembler &Asm,
                                       SectionIndexMapTy &SectionIndexMap,
-                                      const RelMapTy &RelMap) {
+                                      RelMapTy &RelMap) {
   unsigned Index = 1;
   for (MCAssembler::iterator it = Asm.begin(),
          ie = Asm.end(); it != ie; ++it) {
@@ -956,16 +957,20 @@ void ELFObjectWriter::ComputeIndexMap(MC
 
   for (MCAssembler::iterator it = Asm.begin(),
          ie = Asm.end(); it != ie; ++it) {
+    const MCSectionData &SD = *it;
     const MCSectionELF &Section =
-      static_cast<const MCSectionELF &>(it->getSection());
+      static_cast<const MCSectionELF &>(SD.getSection());
     if (Section.getType() == ELF::SHT_GROUP ||
         Section.getType() == ELF::SHT_REL ||
         Section.getType() == ELF::SHT_RELA)
       continue;
     SectionIndexMap[&Section] = Index++;
-    const MCSectionELF *RelSection = RelMap.lookup(&Section);
-    if (RelSection)
+    if (MCSectionData *RelSD = createRelocationSection(Asm, SD)) {
+      const MCSectionELF *RelSection =
+          static_cast<const MCSectionELF *>(&RelSD->getSection());
+      RelMap[&Section] = RelSection;
       SectionIndexMap[RelSection] = Index++;
+    }
   }
 }
 
@@ -1115,42 +1120,37 @@ ELFObjectWriter::computeSymbolTable(MCAs
     UndefinedSymbolData[i].SymbolData->setIndex(Index++);
 }
 
-void ELFObjectWriter::CreateRelocationSections(MCAssembler &Asm,
-                                               RelMapTy &RelMap) {
-  for (MCAssembler::const_iterator it = Asm.begin(),
-         ie = Asm.end(); it != ie; ++it) {
-    const MCSectionData &SD = *it;
-    if (Relocations[&SD].empty())
-      continue;
-
-    MCContext &Ctx = Asm.getContext();
-    const MCSectionELF &Section =
-      static_cast<const MCSectionELF&>(SD.getSection());
+MCSectionData *
+ELFObjectWriter::createRelocationSection(MCAssembler &Asm,
+                                         const MCSectionData &SD) {
+  if (Relocations[&SD].empty())
+    return nullptr;
 
-    const StringRef SectionName = Section.getSectionName();
-    std::string RelaSectionName = hasRelocationAddend() ? ".rela" : ".rel";
-    RelaSectionName += SectionName;
-
-    unsigned EntrySize;
-    if (hasRelocationAddend())
-      EntrySize = is64Bit() ? sizeof(ELF::Elf64_Rela) : sizeof(ELF::Elf32_Rela);
-    else
-      EntrySize = is64Bit() ? sizeof(ELF::Elf64_Rel) : sizeof(ELF::Elf32_Rel);
+  MCContext &Ctx = Asm.getContext();
+  const MCSectionELF &Section =
+      static_cast<const MCSectionELF &>(SD.getSection());
 
-    unsigned Flags = 0;
-    StringRef Group = "";
-    if (Section.getFlags() & ELF::SHF_GROUP) {
-      Flags = ELF::SHF_GROUP;
-      Group = Section.getGroup()->getName();
-    }
+  const StringRef SectionName = Section.getSectionName();
+  std::string RelaSectionName = hasRelocationAddend() ? ".rela" : ".rel";
+  RelaSectionName += SectionName;
+
+  unsigned EntrySize;
+  if (hasRelocationAddend())
+    EntrySize = is64Bit() ? sizeof(ELF::Elf64_Rela) : sizeof(ELF::Elf32_Rela);
+  else
+    EntrySize = is64Bit() ? sizeof(ELF::Elf64_Rel) : sizeof(ELF::Elf32_Rel);
 
-    const MCSectionELF *RelaSection =
-      Ctx.getELFSection(RelaSectionName, hasRelocationAddend() ?
-                        ELF::SHT_RELA : ELF::SHT_REL, Flags,
-                        EntrySize, Group);
-    RelMap[&Section] = RelaSection;
-    Asm.getOrCreateSectionData(*RelaSection);
+  unsigned Flags = 0;
+  StringRef Group = "";
+  if (Section.getFlags() & ELF::SHF_GROUP) {
+    Flags = ELF::SHF_GROUP;
+    Group = Section.getGroup()->getName();
   }
+
+  const MCSectionELF *RelaSection = Ctx.getELFSection(
+      RelaSectionName, hasRelocationAddend() ? ELF::SHT_RELA : ELF::SHT_REL,
+      Flags, EntrySize, Group);
+  return &Asm.getOrCreateSectionData(*RelaSection);
 }
 
 static SmallVector<char, 128>
@@ -1445,12 +1445,12 @@ void ELFObjectWriter::CreateMetadataSect
                           ShStrTabBuilder.data().end());
 }
 
-void ELFObjectWriter::CreateIndexedSections(MCAssembler &Asm,
+void ELFObjectWriter::createIndexedSections(MCAssembler &Asm,
                                             MCAsmLayout &Layout,
                                             GroupMapTy &GroupMap,
                                             RevGroupMapTy &RevGroupMap,
                                             SectionIndexMapTy &SectionIndexMap,
-                                            const RelMapTy &RelMap) {
+                                            RelMapTy &RelMap) {
   MCContext &Ctx = Asm.getContext();
 
   // Build the groups
@@ -1474,7 +1474,7 @@ void ELFObjectWriter::CreateIndexedSecti
     GroupMap[Group] = SignatureSymbol;
   }
 
-  ComputeIndexMap(Asm, SectionIndexMap, RelMap);
+  computeIndexMap(Asm, SectionIndexMap, RelMap);
 
   // Add sections to the groups
   for (MCAssembler::const_iterator it = Asm.begin(), ie = Asm.end();
@@ -1716,10 +1716,8 @@ void ELFObjectWriter::WriteObject(MCAsse
   CompressDebugSections(Asm, const_cast<MCAsmLayout &>(Layout));
 
   DenseMap<const MCSectionELF*, const MCSectionELF*> RelMap;
-  CreateRelocationSections(Asm, RelMap);
-
   const unsigned NumUserAndRelocSections = Asm.size();
-  CreateIndexedSections(Asm, const_cast<MCAsmLayout&>(Layout), GroupMap,
+  createIndexedSections(Asm, const_cast<MCAsmLayout&>(Layout), GroupMap,
                         RevGroupMap, SectionIndexMap, RelMap);
   const unsigned AllSections = Asm.size();
   const unsigned NumIndexedSections = AllSections - NumUserAndRelocSections;