Subzero. Refactors Switch Lowering.

src/IceELFObjectWriter.cpp

 //===- subzero/src/IceELFObjectWriter.cpp - ELF object file writer --------===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 564 matching lines @@
 }
 
 void ELFObjectWriter::writeJumpTable(const JumpTableData &JT,
                                      FixupKind RelocationKind, bool IsPIC) {
   TimerMarker Timer(TimerStack::TT_writeELF, &Ctx);
   ELFDataSection *Section;
   ELFRelocationSection *RelSection;
   const Elf64_Xword PointerSize = typeWidthInBytes(getPointerType());
   const Elf64_Xword ShAddralign = PointerSize;
   const Elf64_Xword ShEntsize = PointerSize;
-  const GlobalString JTName = JT.getFunctionName();
   const std::string SectionName = MangleSectionName(
-      IsPIC ? ".data.rel.ro" : ".rodata",
-      (JTName.hasStdString() ? JTName.toString()
-                             : std::to_string(JTName.getID())) +
-          "$jumptable");
+      IsPIC ? ".data.rel.ro" : ".rodata", JT.getSectionName());

[Jim Stichnoth, 2016/04/04 13:42:30]

It bothers me a tiny bit that we are instantiating the getSectionName() string.

I wonder if maybe we should only call MangleSectionName if -fdata-sections is
specified?

The same would apply to the x86 target emit routines.

[John, 2016/04/05 12:22:43]

This would change sz's output, so I'll leave as is.

This seems to be part of a larger "problem": we don't have a centralized
"section name factory," which would be nice to have so that we would have
control over how/when these strings are created.

   Section = createSection<ELFDataSection>(SectionName, SHT_PROGBITS, SHF_ALLOC,
                                           ShAddralign, ShEntsize);
   Section->setFileOffset(alignFileOffset(ShAddralign));
   RODataSections.push_back(Section);
   RelSection = createRelocationSection(Section);
   RelRODataSections.push_back(RelSection);
 
   constexpr uint8_t SymbolType = STT_OBJECT;
   Section->padToAlignment(Str, PointerSize);
   const bool IsExternal = Ctx.getFlags().getDisableInternal();
   const uint8_t SymbolBinding = IsExternal ? STB_GLOBAL : STB_LOCAL;
-  GlobalString JumpTableName = Ctx.getGlobalString(
-      InstJumpTable::makeName(JT.getFunctionName(), JT.getId()));
+  const auto JumpTableName = JT.getName();
   SymTab->createDefinedSym(JumpTableName, SymbolType, SymbolBinding, Section,
                            Section->getCurrentSize(), PointerSize);
   StrTab->add(JumpTableName);
 
   for (intptr_t TargetOffset : JT.getTargetOffsets()) {
     AssemblerFixup NewFixup;
     NewFixup.set_position(Section->getCurrentSize());
     NewFixup.set_kind(RelocationKind);
     NewFixup.set_value(Ctx.getConstantSym(TargetOffset, JT.getFunctionName()));
     RelSection->addRelocation(NewFixup);
@@ skipping 79 matching lines @@
   if (ELF64) {
     writeELFHeaderInternal<true>(ShOffset, ShStrTab->getNumber(),
                                  AllSections.size());
   } else {
     writeELFHeaderInternal<false>(ShOffset, ShStrTab->getNumber(),
                                   AllSections.size());
   }
 }
 
 } // end of namespace Ice