Move alignment from MCSectionData to MCSection.

This starts merging MCSection and MCSectionData.

There are a few issues with the current split between MCSection and
MCSectionData.

* It optimizes the the not as important case. We want the production
of .o files to be really fast, but the split puts the information used
for .o emission in a separate data structure.

* The ELF/COFF/MachO hierarchy is not represented in MCSectionData,
leading to some ad-hoc ways to represent the various flags.

* It makes it harder to remember where each item is.

The attached patch starts merging the two by moving the alignment from
MCSectionData to MCSection.

Most of the patch is actually just dropping 'const', since
MCSectionData is mutable, but MCSection was not.

llvm-svn: 237936

1 files changed, 31 insertions, 38 deletions

diff --git a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
index 69142d7..a32bdf8 100644
--- a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
+++ b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
@@ -69,10 +69,8 @@ void TargetLoweringObjectFileELF::emitPersonalityValue(MCStreamer &Streamer,
   StringRef Prefix = ".data.";
   NameData.insert(NameData.begin(), Prefix.begin(), Prefix.end());
   unsigned Flags = ELF::SHF_ALLOC | ELF::SHF_WRITE | ELF::SHF_GROUP;
-  const MCSection *Sec = getContext().getELFSection(NameData,
-                                                    ELF::SHT_PROGBITS,
-                                                    Flags,
-                                                    0, Label->getName());
+  MCSection *Sec = getContext().getELFSection(NameData, ELF::SHT_PROGBITS,
+                                              Flags, 0, Label->getName());
   unsigned Size = TM.getDataLayout()->getPointerSize();
   Streamer.SwitchSection(Sec);
   Streamer.EmitValueToAlignment(TM.getDataLayout()->getPointerABIAlignment());
@@ -201,7 +199,7 @@ static const Comdat *getELFComdat(const GlobalValue *GV) {
   return C;
 }
 
-const MCSection *TargetLoweringObjectFileELF::getExplicitSectionGlobal(
+MCSection *TargetLoweringObjectFileELF::getExplicitSectionGlobal(
     const GlobalValue *GV, SectionKind Kind, Mangler &Mang,
     const TargetMachine &TM) const {
   StringRef SectionName = GV->getSection();
@@ -245,7 +243,7 @@ static StringRef getSectionPrefixForGlobal(SectionKind Kind) {
   return ".data.rel.ro";
 }
 
-static const MCSectionELF *
+static MCSectionELF *
 selectELFSectionForGlobal(MCContext &Ctx, const GlobalValue *GV,
                           SectionKind Kind, Mangler &Mang,
                           const TargetMachine &TM, bool EmitUniqueSection,
@@ -308,7 +306,7 @@ selectELFSectionForGlobal(MCContext &Ctx, const GlobalValue *GV,
                            EntrySize, Group, UniqueID);
 }
 
-const MCSection *TargetLoweringObjectFileELF::SelectSectionForGlobal(
+MCSection *TargetLoweringObjectFileELF::SelectSectionForGlobal(
     const GlobalValue *GV, SectionKind Kind, Mangler &Mang,
     const TargetMachine &TM) const {
   unsigned Flags = getELFSectionFlags(Kind);
@@ -328,7 +326,7 @@ const MCSection *TargetLoweringObjectFileELF::SelectSectionForGlobal(
                                    EmitUniqueSection, Flags, &NextUniqueID);
 }
 
-const MCSection *TargetLoweringObjectFileELF::getSectionForJumpTable(
+MCSection *TargetLoweringObjectFileELF::getSectionForJumpTable(
     const Function &F, Mangler &Mang, const TargetMachine &TM) const {
   // If the function can be removed, produce a unique section so that
   // the table doesn't prevent the removal.
@@ -349,10 +347,9 @@ bool TargetLoweringObjectFileELF::shouldPutJumpTableInFunctionSection(
   return false;
 }
 
-/// getSectionForConstant - Given a mergeable constant with the
-/// specified size and relocation information, return a section that it
-/// should be placed in.
-const MCSection *
+/// Given a mergeable constant with the specified size and relocation
+/// information, return a section that it should be placed in.
+MCSection *
 TargetLoweringObjectFileELF::getSectionForConstant(SectionKind Kind,
                                                    const Constant *C) const {
   if (Kind.isMergeableConst4() && MergeableConst4Section)
@@ -369,11 +366,9 @@ TargetLoweringObjectFileELF::getSectionForConstant(SectionKind Kind,
   return DataRelROSection;
 }
 
-static const MCSectionELF *getStaticStructorSection(MCContext &Ctx,
-                                                    bool UseInitArray,
-                                                    bool IsCtor,
-                                                    unsigned Priority,
-                                                    const MCSymbol *KeySym) {
+static MCSectionELF *getStaticStructorSection(MCContext &Ctx, bool UseInitArray,
+                                              bool IsCtor, unsigned Priority,
+                                              const MCSymbol *KeySym) {
   std::string Name;
   unsigned Type;
   unsigned Flags = ELF::SHF_ALLOC | ELF::SHF_WRITE;
@@ -411,13 +406,13 @@ static const MCSectionELF *getStaticStructorSection(MCContext &Ctx,
   return Ctx.getELFSection(Name, Type, Flags, 0, COMDAT);
 }
 
-const MCSection *TargetLoweringObjectFileELF::getStaticCtorSection(
+MCSection *TargetLoweringObjectFileELF::getStaticCtorSection(
     unsigned Priority, const MCSymbol *KeySym) const {
   return getStaticStructorSection(getContext(), UseInitArray, true, Priority,
                                   KeySym);
 }
 
-const MCSection *TargetLoweringObjectFileELF::getStaticDtorSection(
+MCSection *TargetLoweringObjectFileELF::getStaticDtorSection(
     unsigned Priority, const MCSymbol *KeySym) const {
   return getStaticStructorSection(getContext(), UseInitArray, false, Priority,
                                   KeySym);
@@ -520,9 +515,8 @@ emitModuleFlags(MCStreamer &Streamer,
                        ErrorCode + ".");
 
   // Get the section.
-  const MCSectionMachO *S =
-    getContext().getMachOSection(Segment, Section, TAA, StubSize,
-                                 SectionKind::getDataNoRel());
+  MCSectionMachO *S = getContext().getMachOSection(
+      Segment, Section, TAA, StubSize, SectionKind::getDataNoRel());
   Streamer.SwitchSection(S);
   Streamer.EmitLabel(getContext().
                      getOrCreateSymbol(StringRef("L_OBJC_IMAGE_INFO")));
@@ -540,7 +534,7 @@ static void checkMachOComdat(const GlobalValue *GV) {
                      "' cannot be lowered.");
 }
 
-const MCSection *TargetLoweringObjectFileMachO::getExplicitSectionGlobal(
+MCSection *TargetLoweringObjectFileMachO::getExplicitSectionGlobal(
     const GlobalValue *GV, SectionKind Kind, Mangler &Mang,
     const TargetMachine &TM) const {
   // Parse the section specifier and create it if valid.
@@ -561,8 +555,8 @@ const MCSection *TargetLoweringObjectFileMachO::getExplicitSectionGlobal(
   }
 
   // Get the section.
-  const MCSectionMachO *S =
-    getContext().getMachOSection(Segment, Section, TAA, StubSize, Kind);
+  MCSectionMachO *S =
+      getContext().getMachOSection(Segment, Section, TAA, StubSize, Kind);
 
   // If TAA wasn't set by ParseSectionSpecifier() above,
   // use the value returned by getMachOSection() as a default.
@@ -582,9 +576,9 @@ const MCSection *TargetLoweringObjectFileMachO::getExplicitSectionGlobal(
   return S;
 }
 
-const MCSection *TargetLoweringObjectFileMachO::
-SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
-                       Mangler &Mang, const TargetMachine &TM) const {
+MCSection *TargetLoweringObjectFileMachO::SelectSectionForGlobal(
+    const GlobalValue *GV, SectionKind Kind, Mangler &Mang,
+    const TargetMachine &TM) const {
   checkMachOComdat(GV);
 
   // Handle thread local data.
@@ -649,7 +643,7 @@ SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
   return DataSection;
 }
 
-const MCSection *
+MCSection *
 TargetLoweringObjectFileMachO::getSectionForConstant(SectionKind Kind,
                                                      const Constant *C) const {
   // If this constant requires a relocation, we have to put it in the data
@@ -861,7 +855,7 @@ static int getSelectionForCOFF(const GlobalValue *GV) {
   return 0;
 }
 
-const MCSection *TargetLoweringObjectFileCOFF::getExplicitSectionGlobal(
+MCSection *TargetLoweringObjectFileCOFF::getExplicitSectionGlobal(
     const GlobalValue *GV, SectionKind Kind, Mangler &Mang,
     const TargetMachine &TM) const {
   int Selection = 0;
@@ -903,10 +897,9 @@ static const char *getCOFFSectionNameForUniqueGlobal(SectionKind Kind) {
   return ".data";
 }
 
-
-const MCSection *TargetLoweringObjectFileCOFF::
-SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
-                       Mangler &Mang, const TargetMachine &TM) const {
+MCSection *TargetLoweringObjectFileCOFF::SelectSectionForGlobal(
+    const GlobalValue *GV, SectionKind Kind, Mangler &Mang,
+    const TargetMachine &TM) const {
   // If we have -ffunction-sections then we should emit the global value to a
   // uniqued section specifically for it.
   bool EmitUniquedSection;
@@ -971,7 +964,7 @@ void TargetLoweringObjectFileCOFF::getNameWithPrefix(
   Mang.getNameWithPrefix(OutName, GV, CannotUsePrivateLabel);
 }
 
-const MCSection *TargetLoweringObjectFileCOFF::getSectionForJumpTable(
+MCSection *TargetLoweringObjectFileCOFF::getSectionForJumpTable(
     const Function &F, Mangler &Mang, const TargetMachine &TM) const {
   // If the function can be removed, produce a unique section so that
   // the table doesn't prevent the removal.
@@ -1026,7 +1019,7 @@ emitModuleFlags(MCStreamer &Streamer,
 
   // Emit the linker options to the linker .drectve section.  According to the
   // spec, this section is a space-separated string containing flags for linker.
-  const MCSection *Sec = getDrectveSection();
+  MCSection *Sec = getDrectveSection();
   Streamer.SwitchSection(Sec);
   for (unsigned i = 0, e = LinkerOptions->getNumOperands(); i != e; ++i) {
     MDNode *MDOptions = cast<MDNode>(LinkerOptions->getOperand(i));
@@ -1040,13 +1033,13 @@ emitModuleFlags(MCStreamer &Streamer,
   }
 }
 
-const MCSection *TargetLoweringObjectFileCOFF::getStaticCtorSection(
+MCSection *TargetLoweringObjectFileCOFF::getStaticCtorSection(
     unsigned Priority, const MCSymbol *KeySym) const {
   return getContext().getAssociativeCOFFSection(
       cast<MCSectionCOFF>(StaticCtorSection), KeySym);
 }
 
-const MCSection *TargetLoweringObjectFileCOFF::getStaticDtorSection(
+MCSection *TargetLoweringObjectFileCOFF::getStaticDtorSection(
     unsigned Priority, const MCSymbol *KeySym) const {
   return getContext().getAssociativeCOFFSection(
       cast<MCSectionCOFF>(StaticDtorSection), KeySym);