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llvm-mirror/lib/Target/Mips/MipsTargetMachine.cpp
John Baldwin 11b5968641 [MIPS] Implement support for -mstack-alignment.
Summary:
This is modeled on the implementation for x86 which stores the command line
option in a 'StackAlignOverride' field in MipsSubtarget and then uses this
to compute a 'stackAlignment' value in
MipsSubtarget::initializeSubtargetDependencies.

The stackAlignment() method in MipsSubTarget is renamed to getStackAlignment()
and returns the computed 'stackAlignment'.

Reviewers: sdardis

Reviewed By: sdardis

Subscribers: llvm-commits, arichardson

Differential Revision: https://reviews.llvm.org/D35874

llvm-svn: 310891
2017-08-14 21:49:38 +00:00

290 lines
11 KiB
C++

//===-- MipsTargetMachine.cpp - Define TargetMachine for Mips -------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Implements the info about Mips target spec.
//
//===----------------------------------------------------------------------===//
#include "MipsTargetMachine.h"
#include "MCTargetDesc/MipsABIInfo.h"
#include "MCTargetDesc/MipsMCTargetDesc.h"
#include "Mips.h"
#include "Mips16ISelDAGToDAG.h"
#include "MipsSEISelDAGToDAG.h"
#include "MipsSubtarget.h"
#include "MipsTargetObjectFile.h"
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Analysis/TargetTransformInfo.h"
#include "llvm/CodeGen/BasicTTIImpl.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/CodeGen/TargetPassConfig.h"
#include "llvm/IR/Attributes.h"
#include "llvm/IR/Function.h"
#include "llvm/Support/CodeGen.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetOptions.h"
#include <string>
using namespace llvm;
#define DEBUG_TYPE "mips"
extern "C" void LLVMInitializeMipsTarget() {
// Register the target.
RegisterTargetMachine<MipsebTargetMachine> X(getTheMipsTarget());
RegisterTargetMachine<MipselTargetMachine> Y(getTheMipselTarget());
RegisterTargetMachine<MipsebTargetMachine> A(getTheMips64Target());
RegisterTargetMachine<MipselTargetMachine> B(getTheMips64elTarget());
}
static std::string computeDataLayout(const Triple &TT, StringRef CPU,
const TargetOptions &Options,
bool isLittle) {
std::string Ret;
MipsABIInfo ABI = MipsABIInfo::computeTargetABI(TT, CPU, Options.MCOptions);
// There are both little and big endian mips.
if (isLittle)
Ret += "e";
else
Ret += "E";
if (ABI.IsO32())
Ret += "-m:m";
else
Ret += "-m:e";
// Pointers are 32 bit on some ABIs.
if (!ABI.IsN64())
Ret += "-p:32:32";
// 8 and 16 bit integers only need to have natural alignment, but try to
// align them to 32 bits. 64 bit integers have natural alignment.
Ret += "-i8:8:32-i16:16:32-i64:64";
// 32 bit registers are always available and the stack is at least 64 bit
// aligned. On N64 64 bit registers are also available and the stack is
// 128 bit aligned.
if (ABI.IsN64() || ABI.IsN32())
Ret += "-n32:64-S128";
else
Ret += "-n32-S64";
return Ret;
}
static Reloc::Model getEffectiveRelocModel(bool JIT,
Optional<Reloc::Model> RM) {
if (!RM.hasValue() || JIT)
return Reloc::Static;
return *RM;
}
static CodeModel::Model getEffectiveCodeModel(Optional<CodeModel::Model> CM) {
if (CM)
return *CM;
return CodeModel::Small;
}
// On function prologue, the stack is created by decrementing
// its pointer. Once decremented, all references are done with positive
// offset from the stack/frame pointer, using StackGrowsUp enables
// an easier handling.
// Using CodeModel::Large enables different CALL behavior.
MipsTargetMachine::MipsTargetMachine(const Target &T, const Triple &TT,
StringRef CPU, StringRef FS,
const TargetOptions &Options,
Optional<Reloc::Model> RM,
Optional<CodeModel::Model> CM,
CodeGenOpt::Level OL, bool JIT,
bool isLittle)
: LLVMTargetMachine(T, computeDataLayout(TT, CPU, Options, isLittle), TT,
CPU, FS, Options, getEffectiveRelocModel(JIT, RM),
getEffectiveCodeModel(CM), OL),
isLittle(isLittle), TLOF(llvm::make_unique<MipsTargetObjectFile>()),
ABI(MipsABIInfo::computeTargetABI(TT, CPU, Options.MCOptions)),
Subtarget(nullptr), DefaultSubtarget(TT, CPU, FS, isLittle, *this,
Options.StackAlignmentOverride),
NoMips16Subtarget(TT, CPU, FS.empty() ? "-mips16" : FS.str() + ",-mips16",
isLittle, *this, Options.StackAlignmentOverride),
Mips16Subtarget(TT, CPU, FS.empty() ? "+mips16" : FS.str() + ",+mips16",
isLittle, *this, Options.StackAlignmentOverride) {
Subtarget = &DefaultSubtarget;
initAsmInfo();
}
MipsTargetMachine::~MipsTargetMachine() = default;
void MipsebTargetMachine::anchor() {}
MipsebTargetMachine::MipsebTargetMachine(const Target &T, const Triple &TT,
StringRef CPU, StringRef FS,
const TargetOptions &Options,
Optional<Reloc::Model> RM,
Optional<CodeModel::Model> CM,
CodeGenOpt::Level OL, bool JIT)
: MipsTargetMachine(T, TT, CPU, FS, Options, RM, CM, OL, JIT, false) {}
void MipselTargetMachine::anchor() {}
MipselTargetMachine::MipselTargetMachine(const Target &T, const Triple &TT,
StringRef CPU, StringRef FS,
const TargetOptions &Options,
Optional<Reloc::Model> RM,
Optional<CodeModel::Model> CM,
CodeGenOpt::Level OL, bool JIT)
: MipsTargetMachine(T, TT, CPU, FS, Options, RM, CM, OL, JIT, true) {}
const MipsSubtarget *
MipsTargetMachine::getSubtargetImpl(const Function &F) const {
Attribute CPUAttr = F.getFnAttribute("target-cpu");
Attribute FSAttr = F.getFnAttribute("target-features");
std::string CPU = !CPUAttr.hasAttribute(Attribute::None)
? CPUAttr.getValueAsString().str()
: TargetCPU;
std::string FS = !FSAttr.hasAttribute(Attribute::None)
? FSAttr.getValueAsString().str()
: TargetFS;
bool hasMips16Attr =
!F.getFnAttribute("mips16").hasAttribute(Attribute::None);
bool hasNoMips16Attr =
!F.getFnAttribute("nomips16").hasAttribute(Attribute::None);
bool HasMicroMipsAttr =
!F.getFnAttribute("micromips").hasAttribute(Attribute::None);
bool HasNoMicroMipsAttr =
!F.getFnAttribute("nomicromips").hasAttribute(Attribute::None);
// FIXME: This is related to the code below to reset the target options,
// we need to know whether or not the soft float flag is set on the
// function, so we can enable it as a subtarget feature.
bool softFloat =
F.hasFnAttribute("use-soft-float") &&
F.getFnAttribute("use-soft-float").getValueAsString() == "true";
if (hasMips16Attr)
FS += FS.empty() ? "+mips16" : ",+mips16";
else if (hasNoMips16Attr)
FS += FS.empty() ? "-mips16" : ",-mips16";
if (HasMicroMipsAttr)
FS += FS.empty() ? "+micromips" : ",+micromips";
else if (HasNoMicroMipsAttr)
FS += FS.empty() ? "-micromips" : ",-micromips";
if (softFloat)
FS += FS.empty() ? "+soft-float" : ",+soft-float";
auto &I = SubtargetMap[CPU + FS];
if (!I) {
// This needs to be done before we create a new subtarget since any
// creation will depend on the TM and the code generation flags on the
// function that reside in TargetOptions.
resetTargetOptions(F);
I = llvm::make_unique<MipsSubtarget>(TargetTriple, CPU, FS, isLittle,
*this, Options.StackAlignmentOverride);
}
return I.get();
}
void MipsTargetMachine::resetSubtarget(MachineFunction *MF) {
DEBUG(dbgs() << "resetSubtarget\n");
Subtarget = const_cast<MipsSubtarget *>(getSubtargetImpl(*MF->getFunction()));
MF->setSubtarget(Subtarget);
}
namespace {
/// Mips Code Generator Pass Configuration Options.
class MipsPassConfig : public TargetPassConfig {
public:
MipsPassConfig(MipsTargetMachine &TM, PassManagerBase &PM)
: TargetPassConfig(TM, PM) {
// The current implementation of long branch pass requires a scratch
// register ($at) to be available before branch instructions. Tail merging
// can break this requirement, so disable it when long branch pass is
// enabled.
EnableTailMerge = !getMipsSubtarget().enableLongBranchPass();
}
MipsTargetMachine &getMipsTargetMachine() const {
return getTM<MipsTargetMachine>();
}
const MipsSubtarget &getMipsSubtarget() const {
return *getMipsTargetMachine().getSubtargetImpl();
}
void addIRPasses() override;
bool addInstSelector() override;
void addPreEmitPass() override;
void addPreRegAlloc() override;
};
} // end anonymous namespace
TargetPassConfig *MipsTargetMachine::createPassConfig(PassManagerBase &PM) {
return new MipsPassConfig(*this, PM);
}
void MipsPassConfig::addIRPasses() {
TargetPassConfig::addIRPasses();
addPass(createAtomicExpandPass());
if (getMipsSubtarget().os16())
addPass(createMipsOs16Pass());
if (getMipsSubtarget().inMips16HardFloat())
addPass(createMips16HardFloatPass());
}
// Install an instruction selector pass using
// the ISelDag to gen Mips code.
bool MipsPassConfig::addInstSelector() {
addPass(createMipsModuleISelDagPass());
addPass(createMips16ISelDag(getMipsTargetMachine(), getOptLevel()));
addPass(createMipsSEISelDag(getMipsTargetMachine(), getOptLevel()));
return false;
}
void MipsPassConfig::addPreRegAlloc() {
addPass(createMipsOptimizePICCallPass());
}
TargetIRAnalysis MipsTargetMachine::getTargetIRAnalysis() {
return TargetIRAnalysis([this](const Function &F) {
if (Subtarget->allowMixed16_32()) {
DEBUG(errs() << "No Target Transform Info Pass Added\n");
// FIXME: This is no longer necessary as the TTI returned is per-function.
return TargetTransformInfo(F.getParent()->getDataLayout());
}
DEBUG(errs() << "Target Transform Info Pass Added\n");
return TargetTransformInfo(BasicTTIImpl(this, F));
});
}
// Implemented by targets that want to run passes immediately before
// machine code is emitted. return true if -print-machineinstrs should
// print out the code after the passes.
void MipsPassConfig::addPreEmitPass() {
addPass(createMicroMipsSizeReductionPass());
// The delay slot filler pass can potientially create forbidden slot (FS)
// hazards for MIPSR6 which the hazard schedule pass (HSP) will fix. Any
// (new) pass that creates compact branches after the HSP must handle FS
// hazards itself or be pipelined before the HSP.
addPass(createMipsDelaySlotFillerPass());
addPass(createMipsHazardSchedule());
addPass(createMipsLongBranchPass());
addPass(createMipsConstantIslandPass());
}