#include "MipsTargetObjectFile.h"
#include "MipsSubtarget.h"
+#include "MipsTargetMachine.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/GlobalVariable.h"
cl::desc("Small data and bss section threshold size (default=8)"),
cl::init(8));
+static cl::opt<bool>
+LocalSData("mlocal-sdata", cl::Hidden,
+ cl::desc("MIPS: Use gp_rel for object-local data."),
+ cl::init(true));
+
+static cl::opt<bool>
+ExternSData("mextern-sdata", cl::Hidden,
+ cl::desc("MIPS: Use gp_rel for data that is not defined by the "
+ "current object."),
+ cl::init(true));
+
void MipsTargetObjectFile::Initialize(MCContext &Ctx, const TargetMachine &TM){
TargetLoweringObjectFileELF::Initialize(Ctx, TM);
InitializeELF(TM.Options.UseInitArray);
- SmallDataSection =
- getContext().getELFSection(".sdata", ELF::SHT_PROGBITS,
- ELF::SHF_WRITE |ELF::SHF_ALLOC,
- SectionKind::getDataRel());
+ SmallDataSection = getContext().getELFSection(
+ ".sdata", ELF::SHT_PROGBITS, ELF::SHF_WRITE | ELF::SHF_ALLOC);
- SmallBSSSection =
- getContext().getELFSection(".sbss", ELF::SHT_NOBITS,
- ELF::SHF_WRITE |ELF::SHF_ALLOC,
- SectionKind::getBSS());
+ SmallBSSSection = getContext().getELFSection(".sbss", ELF::SHT_NOBITS,
+ ELF::SHF_WRITE | ELF::SHF_ALLOC);
+ this->TM = &static_cast<const MipsTargetMachine &>(TM);
}
// A address must be loaded from a small section if its size is less than the
// small section size threshold. Data in this section must be addressed using
// gp_rel operator.
static bool IsInSmallSection(uint64_t Size) {
+ // gcc has traditionally not treated zero-sized objects as small data, so this
+ // is effectively part of the ABI.
return Size > 0 && Size <= SSThreshold;
}
-bool MipsTargetObjectFile::IsGlobalInSmallSection(const GlobalValue *GV,
- const TargetMachine &TM) const {
+/// Return true if this global address should be placed into small data/bss
+/// section.
+bool MipsTargetObjectFile::
+IsGlobalInSmallSection(const GlobalValue *GV, const TargetMachine &TM) const {
+ // We first check the case where global is a declaration, because finding
+ // section kind using getKindForGlobal() is only allowed for global
+ // definitions.
if (GV->isDeclaration() || GV->hasAvailableExternallyLinkage())
- return false;
+ return IsGlobalInSmallSectionImpl(GV, TM);
return IsGlobalInSmallSection(GV, TM, getKindForGlobal(GV, TM));
}
-/// IsGlobalInSmallSection - Return true if this global address should be
-/// placed into small data/bss section.
+/// Return true if this global address should be placed into small data/bss
+/// section.
bool MipsTargetObjectFile::
IsGlobalInSmallSection(const GlobalValue *GV, const TargetMachine &TM,
SectionKind Kind) const {
+ return (IsGlobalInSmallSectionImpl(GV, TM) &&
+ (Kind.isDataRel() || Kind.isBSS() || Kind.isCommon()));
+}
- const MipsSubtarget &Subtarget = TM.getSubtarget<MipsSubtarget>();
+/// Return true if this global address should be placed into small data/bss
+/// section. This method does all the work, except for checking the section
+/// kind.
+bool MipsTargetObjectFile::
+IsGlobalInSmallSectionImpl(const GlobalValue *GV,
+ const TargetMachine &TM) const {
+ const MipsSubtarget &Subtarget =
+ *static_cast<const MipsTargetMachine &>(TM).getSubtargetImpl();
// Return if small section is not available.
if (!Subtarget.useSmallSection())
if (!GVA)
return false;
- // We can only do this for datarel or BSS objects for now.
- if (!Kind.isBSS() && !Kind.isDataRel())
+ // Enforce -mlocal-sdata.
+ if (!LocalSData && GV->hasLocalLinkage())
return false;
- // If this is a internal constant string, there is a special
- // section for it, but not in small data/bss.
- if (Kind.isMergeable1ByteCString())
+ // Enforce -mextern-sdata.
+ if (!ExternSData && ((GV->hasExternalLinkage() && GV->isDeclaration()) ||
+ GV->hasCommonLinkage()))
return false;
Type *Ty = GV->getType()->getElementType();
return IsInSmallSection(
- TM.getSubtargetImpl()->getDataLayout()->getTypeAllocSize(Ty));
+ GV->getParent()->getDataLayout().getTypeAllocSize(Ty));
}
-
-
-const MCSection *MipsTargetObjectFile::
-SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
- Mangler &Mang, const TargetMachine &TM) const {
+MCSection *
+MipsTargetObjectFile::SelectSectionForGlobal(const GlobalValue *GV,
+ SectionKind Kind, Mangler &Mang,
+ const TargetMachine &TM) const {
// TODO: Could also support "weak" symbols as well with ".gnu.linkonce.s.*"
// sections?
// Handle Small Section classification here.
if (Kind.isBSS() && IsGlobalInSmallSection(GV, TM, Kind))
return SmallBSSSection;
- if (Kind.isDataNoRel() && IsGlobalInSmallSection(GV, TM, Kind))
+ if (Kind.isDataRel() && IsGlobalInSmallSection(GV, TM, Kind))
return SmallDataSection;
// Otherwise, we work the same as ELF.
return TargetLoweringObjectFileELF::SelectSectionForGlobal(GV, Kind, Mang,TM);
}
+
+/// Return true if this constant should be placed into small data section.
+bool MipsTargetObjectFile::IsConstantInSmallSection(
+ const DataLayout &DL, const Constant *CN, const TargetMachine &TM) const {
+ return (static_cast<const MipsTargetMachine &>(TM)
+ .getSubtargetImpl()
+ ->useSmallSection() &&
+ LocalSData && IsInSmallSection(DL.getTypeAllocSize(CN->getType())));
+}
+
+/// Return true if this constant should be placed into small data section.
+MCSection *MipsTargetObjectFile::getSectionForConstant(
+ const DataLayout &DL, SectionKind Kind, const Constant *C) const {
+ if (IsConstantInSmallSection(DL, C, *TM))
+ return SmallDataSection;
+
+ // Otherwise, we work the same as ELF.
+ return TargetLoweringObjectFileELF::getSectionForConstant(DL, Kind, C);
+}
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