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04bcc11905
derived classes. Since global data alignment, layout, and mangling is often based on the DataLayout, move it to the TargetMachine. This ensures that global data is going to be layed out and mangled consistently if the subtarget changes on a per function basis. Prior to this all targets(*) have had subtarget dependent code moved out and onto the TargetMachine. *One target hasn't been migrated as part of this change: R600. The R600 port has, as a subtarget feature, the size of pointers and this affects global data layout. I've currently hacked in a FIXME to enable progress, but the port needs to be updated to either pass the 64-bitness to the TargetMachine, or fix the DataLayout to avoid subtarget dependent features. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227113 91177308-0d34-0410-b5e6-96231b3b80d8
102 lines
3.8 KiB
C++
102 lines
3.8 KiB
C++
//===-- HexagonTargetObjectFile.cpp - Hexagon asm properties --------------===//
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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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//
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// This file contains the declarations of the HexagonTargetAsmInfo properties.
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//
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//===----------------------------------------------------------------------===//
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#include "HexagonTargetObjectFile.h"
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#include "HexagonSubtarget.h"
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#include "HexagonTargetMachine.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/Function.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/Support/CommandLine.h"
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#include "llvm/Support/ELF.h"
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using namespace llvm;
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static cl::opt<int> SmallDataThreshold("hexagon-small-data-threshold",
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cl::init(8), cl::Hidden,
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cl::desc("The maximum size of an object in the sdata section"));
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void HexagonTargetObjectFile::Initialize(MCContext &Ctx,
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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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}
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// sdata/sbss support taken largely from the MIPS Backend.
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static bool IsInSmallSection(uint64_t Size) {
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return Size > 0 && Size <= (uint64_t)SmallDataThreshold;
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}
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bool HexagonTargetObjectFile::IsSmallDataEnabled () const {
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return SmallDataThreshold > 0;
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}
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/// IsGlobalInSmallSection - Return true if this global value should be
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/// placed into small data/bss section.
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bool HexagonTargetObjectFile::IsGlobalInSmallSection(const GlobalValue *GV,
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const TargetMachine &TM) const {
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// If the primary definition of this global value is outside the current
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// translation unit or the global value is available for inspection but not
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// emission, then do nothing.
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if (GV->isDeclaration() || GV->hasAvailableExternallyLinkage())
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return false;
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// Otherwise, Check if GV should be in sdata/sbss, when normally it would end
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// up in getKindForGlobal(GV, TM).
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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 value should be
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/// placed into small data/bss section.
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bool HexagonTargetObjectFile::
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IsGlobalInSmallSection(const GlobalValue *GV, const TargetMachine &TM,
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SectionKind Kind) const {
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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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if (Kind.isBSS() || Kind.isDataNoRel() || Kind.isCommon()) {
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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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return false;
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}
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const MCSection *
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HexagonTargetObjectFile::SelectSectionForGlobal(const GlobalValue *GV,
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SectionKind Kind, Mangler &Mang,
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const TargetMachine &TM) const {
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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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