[llvm] r233539 - Special case the creation of relocation sections.

[Rafael Espindola]

Author: rafael
Date: Mon Mar 30 08:39:16 2015
New Revision: 233539

URL: http://llvm.org/viewvc/llvm-project?rev=233539&view=rev
Log:
Special case the creation of relocation sections.

These sections are never looked up and we know when have to create them. Use
that to save adding them to the regular map and avoid a symbol->string->symbol
conversion for the group symbol.

This also makes the implementation independent of the details of how unique
sections are implemented.

Modified:
    llvm/trunk/include/llvm/MC/MCContext.h
    llvm/trunk/lib/MC/ELFObjectWriter.cpp
    llvm/trunk/lib/MC/MCContext.cpp

Modified: llvm/trunk/include/llvm/MC/MCContext.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/MC/MCContext.h?rev=233539&r1=233538&r2=233539&view=diff
==============================================================================
--- llvm/trunk/include/llvm/MC/MCContext.h (original)
+++ llvm/trunk/include/llvm/MC/MCContext.h Mon Mar 30 08:39:16 2015
@@ -194,6 +194,7 @@ namespace llvm {
     StringMap<const MCSectionMachO*> MachOUniquingMap;
     std::map<ELFSectionKey, const MCSectionELF *> ELFUniquingMap;
     std::map<COFFSectionKey, const MCSectionCOFF *> COFFUniquingMap;
+    StringMap<bool> ELFRelSecNames;
 
     /// Do automatic reset in destructor
     bool AutoReset;
@@ -304,6 +305,10 @@ namespace llvm {
                                       StringRef Group, bool Unique,
                                       const char *BeginSymName = nullptr);
 
+    const MCSectionELF *createELFRelSection(StringRef Name, unsigned Type,
+                                            unsigned Flags, unsigned EntrySize,
+                                            const MCSymbol *Group);
+
     void renameELFSection(const MCSectionELF *Section, StringRef Name);
 
     const MCSectionELF *CreateELFGroupSection();

Modified: llvm/trunk/lib/MC/ELFObjectWriter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/ELFObjectWriter.cpp?rev=233539&r1=233538&r2=233539&view=diff
==============================================================================
--- llvm/trunk/lib/MC/ELFObjectWriter.cpp (original)
+++ llvm/trunk/lib/MC/ELFObjectWriter.cpp Mon Mar 30 08:39:16 2015
@@ -1167,15 +1167,12 @@ ELFObjectWriter::createRelocationSection
     EntrySize = is64Bit() ? sizeof(ELF::Elf64_Rel) : sizeof(ELF::Elf32_Rel);
 
   unsigned Flags = 0;
-  StringRef Group = "";
-  if (Section.getFlags() & ELF::SHF_GROUP) {
+  if (Section.getFlags() & ELF::SHF_GROUP)
     Flags = ELF::SHF_GROUP;
-    Group = Section.getGroup()->getName();
-  }
 
-  const MCSectionELF *RelaSection = Ctx.getELFSection(
+  const MCSectionELF *RelaSection = Ctx.createELFRelSection(
       RelaSectionName, hasRelocationAddend() ? ELF::SHT_RELA : ELF::SHT_REL,
-      Flags, EntrySize, Group, true);
+      Flags, EntrySize, Section.getGroup());
   return &Asm.getOrCreateSectionData(*RelaSection);
 }
 

Modified: llvm/trunk/lib/MC/MCContext.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCContext.cpp?rev=233539&r1=233538&r2=233539&view=diff
==============================================================================
--- llvm/trunk/lib/MC/MCContext.cpp (original)
+++ llvm/trunk/lib/MC/MCContext.cpp Mon Mar 30 08:39:16 2015
@@ -275,6 +275,18 @@ void MCContext::renameELFSection(const M
   const_cast<MCSectionELF*>(Section)->setSectionName(CachedName);
 }
 
+const MCSectionELF *
+MCContext::createELFRelSection(StringRef Name, unsigned Type, unsigned Flags,
+                               unsigned EntrySize, const MCSymbol *Group) {
+  StringMap<bool>::iterator I;
+  bool Inserted;
+  std::tie(I, Inserted) = ELFRelSecNames.insert(std::make_pair(Name, true));
+
+  return new (*this)
+      MCSectionELF(I->getKey(), Type, Flags, SectionKind::getReadOnly(),
+                   EntrySize, Group, true, nullptr);
+}
+
 const MCSectionELF *MCContext::getELFSection(StringRef Section, unsigned Type,
                                              unsigned Flags, unsigned EntrySize,
                                              StringRef Group, bool Unique,