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c91cbb9b0c
but I cannot reproduce the problem and have scrubed my sources and even tested with llvm-lit -v --vg. Support for Mips register information sections. Mips ELF object files have a section that is dedicated to register use info. Some of this information such as the assumed Global Pointer value is used by the linker in relocation resolution. The register info file is .reginfo in o32 and .MIPS.options in 64 and n32 abi files. This patch contains the changes needed to create the sections, but leaves the actual register accounting for a future patch. Contributer: Jack Carter git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@172847 91177308-0d34-0410-b5e6-96231b3b80d8
119 lines
4.2 KiB
C++
119 lines
4.2 KiB
C++
//===-- MipsTargetObjectFile.cpp - Mips Object Files ----------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#include "MipsTargetObjectFile.h"
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#include "MipsSubtarget.h"
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#include "llvm/IR/DataLayout.h"
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#include "llvm/IR/DerivedTypes.h"
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#include "llvm/IR/GlobalVariable.h"
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#include "llvm/MC/MCContext.h"
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#include "llvm/MC/MCSectionELF.h"
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#include "llvm/Support/CommandLine.h"
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#include "llvm/Support/ELF.h"
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#include "llvm/Target/TargetMachine.h"
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using namespace llvm;
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static cl::opt<unsigned>
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SSThreshold("mips-ssection-threshold", cl::Hidden,
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cl::desc("Small data and bss section threshold size (default=8)"),
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cl::init(8));
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void MipsTargetObjectFile::Initialize(MCContext &Ctx, const TargetMachine &TM){
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TargetLoweringObjectFileELF::Initialize(Ctx, TM);
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InitializeELF(TM.Options.UseInitArray);
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SmallDataSection =
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getContext().getELFSection(".sdata", ELF::SHT_PROGBITS,
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ELF::SHF_WRITE |ELF::SHF_ALLOC,
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SectionKind::getDataRel());
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SmallBSSSection =
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getContext().getELFSection(".sbss", ELF::SHT_NOBITS,
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ELF::SHF_WRITE |ELF::SHF_ALLOC,
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SectionKind::getBSS());
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// Register info information
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const MipsSubtarget &Subtarget = TM.getSubtarget<MipsSubtarget>();
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if (Subtarget.isABI_N64() || Subtarget.isABI_N32())
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ReginfoSection =
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getContext().getELFSection(".MIPS.options",
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ELF::SHT_MIPS_OPTIONS,
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ELF::SHF_ALLOC |ELF::SHF_MIPS_NOSTRIP,
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SectionKind::getMetadata());
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else
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ReginfoSection =
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getContext().getELFSection(".reginfo",
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ELF::SHT_MIPS_REGINFO,
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ELF::SHF_ALLOC,
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SectionKind::getMetadata());
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}
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// A address must be loaded from a small section if its size is less than the
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// small section size threshold. Data in this section must be addressed using
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// gp_rel operator.
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static bool IsInSmallSection(uint64_t Size) {
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return Size > 0 && Size <= SSThreshold;
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}
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bool MipsTargetObjectFile::IsGlobalInSmallSection(const GlobalValue *GV,
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const TargetMachine &TM) const {
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if (GV->isDeclaration() || GV->hasAvailableExternallyLinkage())
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return false;
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return IsGlobalInSmallSection(GV, TM, getKindForGlobal(GV, TM));
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}
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/// IsGlobalInSmallSection - Return true if this global address should be
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/// placed into small data/bss section.
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bool MipsTargetObjectFile::
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IsGlobalInSmallSection(const GlobalValue *GV, const TargetMachine &TM,
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SectionKind Kind) const {
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const MipsSubtarget &Subtarget = TM.getSubtarget<MipsSubtarget>();
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// Return if small section is not available.
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if (!Subtarget.useSmallSection())
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return false;
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// Only global variables, not functions.
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const GlobalVariable *GVA = dyn_cast<GlobalVariable>(GV);
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if (!GVA)
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return false;
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// We can only do this for datarel or BSS objects for now.
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if (!Kind.isBSS() && !Kind.isDataRel())
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return false;
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// If this is a internal constant string, there is a special
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// section for it, but not in small data/bss.
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if (Kind.isMergeable1ByteCString())
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return false;
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Type *Ty = GV->getType()->getElementType();
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return IsInSmallSection(TM.getDataLayout()->getTypeAllocSize(Ty));
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}
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const MCSection *MipsTargetObjectFile::
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SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
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Mangler *Mang, const TargetMachine &TM) const {
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// TODO: Could also support "weak" symbols as well with ".gnu.linkonce.s.*"
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// sections?
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// Handle Small Section classification here.
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if (Kind.isBSS() && IsGlobalInSmallSection(GV, TM, Kind))
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return SmallBSSSection;
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if (Kind.isDataNoRel() && IsGlobalInSmallSection(GV, TM, Kind))
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return SmallDataSection;
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// Otherwise, we work the same as ELF.
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return TargetLoweringObjectFileELF::SelectSectionForGlobal(GV, Kind, Mang,TM);
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}
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