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llvm-project/llvm/lib/Target/PowerPC/PPCTargetMachine.cpp

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//===-- PPCTargetMachine.cpp - Define TargetMachine for PowerPC -----------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// Top-level implementation for the PowerPC target.
//
//===----------------------------------------------------------------------===//
#include "PPCTargetMachine.h"
#include "MCTargetDesc/PPCMCTargetDesc.h"
#include "PPC.h"
#include "PPCMachineScheduler.h"
#include "PPCSubtarget.h"
#include "PPCTargetObjectFile.h"
#include "PPCTargetTransformInfo.h"
#include "TargetInfo/PowerPCTargetInfo.h"
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/Triple.h"
#include "llvm/Analysis/TargetTransformInfo.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/CodeGen/TargetPassConfig.h"
#include "llvm/CodeGen/MachineScheduler.h"
#include "llvm/IR/Attributes.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/Function.h"
#include "llvm/Pass.h"
#include "llvm/Support/CodeGen.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Target/TargetLoweringObjectFile.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/Transforms/Scalar.h"
#include <cassert>
#include <memory>
#include <string>
using namespace llvm;
static cl::opt<bool>
EnableBranchCoalescing("enable-ppc-branch-coalesce", cl::Hidden,
cl::desc("enable coalescing of duplicate branches for PPC"));
static cl::
opt<bool> DisableCTRLoops("disable-ppc-ctrloops", cl::Hidden,
cl::desc("Disable CTR loops for PPC"));
static cl::
opt<bool> DisablePreIncPrep("disable-ppc-preinc-prep", cl::Hidden,
cl::desc("Disable PPC loop preinc prep"));
static cl::opt<bool>
VSXFMAMutateEarly("schedule-ppc-vsx-fma-mutation-early",
cl::Hidden, cl::desc("Schedule VSX FMA instruction mutation early"));
static cl::
opt<bool> DisableVSXSwapRemoval("disable-ppc-vsx-swap-removal", cl::Hidden,
cl::desc("Disable VSX Swap Removal for PPC"));
static cl::
opt<bool> DisableQPXLoadSplat("disable-ppc-qpx-load-splat", cl::Hidden,
cl::desc("Disable QPX load splat simplification"));
static cl::
opt<bool> DisableMIPeephole("disable-ppc-peephole", cl::Hidden,
cl::desc("Disable machine peepholes for PPC"));
static cl::opt<bool>
EnableGEPOpt("ppc-gep-opt", cl::Hidden,
cl::desc("Enable optimizations on complex GEPs"),
cl::init(true));
static cl::opt<bool>
EnablePrefetch("enable-ppc-prefetching",
cl::desc("disable software prefetching on PPC"),
cl::init(false), cl::Hidden);
static cl::opt<bool>
EnableExtraTOCRegDeps("enable-ppc-extra-toc-reg-deps",
cl::desc("Add extra TOC register dependencies"),
cl::init(true), cl::Hidden);
static cl::opt<bool>
EnableMachineCombinerPass("ppc-machine-combiner",
cl::desc("Enable the machine combiner pass"),
cl::init(true), cl::Hidden);
static cl::opt<bool>
ReduceCRLogical("ppc-reduce-cr-logicals",
cl::desc("Expand eligible cr-logical binary ops to branches"),
cl::init(false), cl::Hidden);
extern "C" void LLVMInitializePowerPCTarget() {
// Register the targets
RegisterTargetMachine<PPCTargetMachine> A(getThePPC32Target());
RegisterTargetMachine<PPCTargetMachine> B(getThePPC64Target());
RegisterTargetMachine<PPCTargetMachine> C(getThePPC64LETarget());
PassRegistry &PR = *PassRegistry::getPassRegistry();
initializePPCCTRLoopsPass(PR);
#ifndef NDEBUG
initializePPCCTRLoopsVerifyPass(PR);
#endif
initializePPCLoopPreIncPrepPass(PR);
initializePPCTOCRegDepsPass(PR);
initializePPCEarlyReturnPass(PR);
initializePPCVSXCopyPass(PR);
initializePPCVSXFMAMutatePass(PR);
initializePPCVSXSwapRemovalPass(PR);
initializePPCReduceCRLogicalsPass(PR);
initializePPCBSelPass(PR);
initializePPCBranchCoalescingPass(PR);
initializePPCQPXLoadSplatPass(PR);
initializePPCBoolRetToIntPass(PR);
initializePPCExpandISELPass(PR);
initializePPCPreEmitPeepholePass(PR);
initializePPCTLSDynamicCallPass(PR);
initializePPCMIPeepholePass(PR);
}
/// Return the datalayout string of a subtarget.
static std::string getDataLayoutString(const Triple &T) {
bool is64Bit = T.getArch() == Triple::ppc64 || T.getArch() == Triple::ppc64le;
std::string Ret;
// Most PPC* platforms are big endian, PPC64LE is little endian.
if (T.getArch() == Triple::ppc64le)
Ret = "e";
else
Ret = "E";
Ret += DataLayout::getManglingComponent(T);
// PPC32 has 32 bit pointers. The PS3 (OS Lv2) is a PPC64 machine with 32 bit
// pointers.
if (!is64Bit || T.getOS() == Triple::Lv2)
Ret += "-p:32:32";
// Note, the alignment values for f64 and i64 on ppc64 in Darwin
// documentation are wrong; these are correct (i.e. "what gcc does").
if (is64Bit || !T.isOSDarwin())
Ret += "-i64:64";
else
Ret += "-f64:32:64";
// PPC64 has 32 and 64 bit registers, PPC32 has only 32 bit ones.
if (is64Bit)
Ret += "-n32:64";
else
Ret += "-n32";
return Ret;
}
static std::string computeFSAdditions(StringRef FS, CodeGenOpt::Level OL,
const Triple &TT) {
std::string FullFS = FS;
// Make sure 64-bit features are available when CPUname is generic
if (TT.getArch() == Triple::ppc64 || TT.getArch() == Triple::ppc64le) {
if (!FullFS.empty())
FullFS = "+64bit," + FullFS;
else
FullFS = "+64bit";
}
if (OL >= CodeGenOpt::Default) {
if (!FullFS.empty())
FullFS = "+crbits," + FullFS;
else
FullFS = "+crbits";
}
if (OL != CodeGenOpt::None) {
if (!FullFS.empty())
FullFS = "+invariant-function-descriptors," + FullFS;
else
FullFS = "+invariant-function-descriptors";
}
return FullFS;
}
static std::unique_ptr<TargetLoweringObjectFile> createTLOF(const Triple &TT) {
// If it isn't a Mach-O file then it's going to be a linux ELF
// object file.
if (TT.isOSDarwin())
return llvm::make_unique<TargetLoweringObjectFileMachO>();
return llvm::make_unique<PPC64LinuxTargetObjectFile>();
}
static PPCTargetMachine::PPCABI computeTargetABI(const Triple &TT,
const TargetOptions &Options) {
if (TT.isOSDarwin())
report_fatal_error("Darwin is no longer supported for PowerPC");
if (Options.MCOptions.getABIName().startswith("elfv1"))
return PPCTargetMachine::PPC_ABI_ELFv1;
else if (Options.MCOptions.getABIName().startswith("elfv2"))
return PPCTargetMachine::PPC_ABI_ELFv2;
assert(Options.MCOptions.getABIName().empty() &&
"Unknown target-abi option!");
if (TT.isMacOSX())
return PPCTargetMachine::PPC_ABI_UNKNOWN;
switch (TT.getArch()) {
case Triple::ppc64le:
return PPCTargetMachine::PPC_ABI_ELFv2;
case Triple::ppc64:
return PPCTargetMachine::PPC_ABI_ELFv1;
default:
return PPCTargetMachine::PPC_ABI_UNKNOWN;
}
}
static Reloc::Model getEffectiveRelocModel(const Triple &TT,
Optional<Reloc::Model> RM) {
if (RM.hasValue())
return *RM;
// Darwin defaults to dynamic-no-pic.
if (TT.isOSDarwin())
return Reloc::DynamicNoPIC;
// Big Endian PPC is PIC by default.
if (TT.getArch() == Triple::ppc64)
return Reloc::PIC_;
// Rest are static by default.
return Reloc::Static;
}
static CodeModel::Model getEffectivePPCCodeModel(const Triple &TT,
Optional<CodeModel::Model> CM,
bool JIT) {
if (CM) {
if (*CM == CodeModel::Tiny)
report_fatal_error("Target does not support the tiny CodeModel");
if (*CM == CodeModel::Kernel)
report_fatal_error("Target does not support the kernel CodeModel");
return *CM;
}
if (!TT.isOSDarwin() && !JIT &&
(TT.getArch() == Triple::ppc64 || TT.getArch() == Triple::ppc64le))
return CodeModel::Medium;
return CodeModel::Small;
}
static ScheduleDAGInstrs *createPPCMachineScheduler(MachineSchedContext *C) {
ScheduleDAGMILive *DAG =
new ScheduleDAGMILive(C, llvm::make_unique<PPCPreRASchedStrategy>(C));
// add DAG Mutations here.
DAG->addMutation(createCopyConstrainDAGMutation(DAG->TII, DAG->TRI));
return DAG;
}
static ScheduleDAGInstrs *createPPCPostMachineScheduler(
MachineSchedContext *C) {
ScheduleDAGMI *DAG =
new ScheduleDAGMI(C, llvm::make_unique<PPCPostRASchedStrategy>(C), true);
// add DAG Mutations here.
return DAG;
}
// The FeatureString here is a little subtle. We are modifying the feature
// string with what are (currently) non-function specific overrides as it goes
// into the LLVMTargetMachine constructor and then using the stored value in the
// Subtarget constructor below it.
PPCTargetMachine::PPCTargetMachine(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)
: LLVMTargetMachine(T, getDataLayoutString(TT), TT, CPU,
computeFSAdditions(FS, OL, TT), Options,
getEffectiveRelocModel(TT, RM),
getEffectivePPCCodeModel(TT, CM, JIT), OL),
TLOF(createTLOF(getTargetTriple())),
TargetABI(computeTargetABI(TT, Options)) {
initAsmInfo();
}
PPCTargetMachine::~PPCTargetMachine() = default;
const PPCSubtarget *
PPCTargetMachine::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;
// 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 before we can generate a subtarget. We also need to use
// it as a key for the subtarget since that can be the only difference
// between two functions.
bool SoftFloat =
F.getFnAttribute("use-soft-float").getValueAsString() == "true";
// If the soft float attribute is set on the function turn on the soft float
// subtarget feature.
if (SoftFloat)
FS += FS.empty() ? "-hard-float" : ",-hard-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<PPCSubtarget>(
TargetTriple, CPU,
// FIXME: It would be good to have the subtarget additions here
// not necessary. Anything that turns them on/off (overrides) ends
// up being put at the end of the feature string, but the defaults
// shouldn't require adding them. Fixing this means pulling Feature64Bit
// out of most of the target cpus in the .td file and making it set only
// as part of initialization via the TargetTriple.
computeFSAdditions(FS, getOptLevel(), getTargetTriple()), *this);
}
return I.get();
}
//===----------------------------------------------------------------------===//
// Pass Pipeline Configuration
//===----------------------------------------------------------------------===//
namespace {
/// PPC Code Generator Pass Configuration Options.
class PPCPassConfig : public TargetPassConfig {
public:
PPCPassConfig(PPCTargetMachine &TM, PassManagerBase &PM)
: TargetPassConfig(TM, PM) {
// At any optimization level above -O0 we use the Machine Scheduler and not
// the default Post RA List Scheduler.
if (TM.getOptLevel() != CodeGenOpt::None)
substitutePass(&PostRASchedulerID, &PostMachineSchedulerID);
}
PPCTargetMachine &getPPCTargetMachine() const {
return getTM<PPCTargetMachine>();
}
void addIRPasses() override;
bool addPreISel() override;
bool addILPOpts() override;
bool addInstSelector() override;
void addMachineSSAOptimization() override;
void addPreRegAlloc() override;
void addPreSched2() override;
void addPreEmitPass() override;
ScheduleDAGInstrs *
createMachineScheduler(MachineSchedContext *C) const override {
const PPCSubtarget &ST = C->MF->getSubtarget<PPCSubtarget>();
if (ST.usePPCPreRASchedStrategy())
return createPPCMachineScheduler(C);
return nullptr;
}
ScheduleDAGInstrs *
createPostMachineScheduler(MachineSchedContext *C) const override {
const PPCSubtarget &ST = C->MF->getSubtarget<PPCSubtarget>();
if (ST.usePPCPostRASchedStrategy())
return createPPCPostMachineScheduler(C);
return nullptr;
}
};
} // end anonymous namespace
TargetPassConfig *PPCTargetMachine::createPassConfig(PassManagerBase &PM) {
return new PPCPassConfig(*this, PM);
}
void PPCPassConfig::addIRPasses() {
if (TM->getOptLevel() != CodeGenOpt::None)
addPass(createPPCBoolRetToIntPass());
addPass(createAtomicExpandPass());
// For the BG/Q (or if explicitly requested), add explicit data prefetch
// intrinsics.
bool UsePrefetching = TM->getTargetTriple().getVendor() == Triple::BGQ &&
getOptLevel() != CodeGenOpt::None;
if (EnablePrefetch.getNumOccurrences() > 0)
UsePrefetching = EnablePrefetch;
if (UsePrefetching)
addPass(createLoopDataPrefetchPass());
if (TM->getOptLevel() >= CodeGenOpt::Default && EnableGEPOpt) {
// Call SeparateConstOffsetFromGEP pass to extract constants within indices
// and lower a GEP with multiple indices to either arithmetic operations or
// multiple GEPs with single index.
addPass(createSeparateConstOffsetFromGEPPass(true));
// Call EarlyCSE pass to find and remove subexpressions in the lowered
// result.
addPass(createEarlyCSEPass());
// Do loop invariant code motion in case part of the lowered result is
// invariant.
addPass(createLICMPass());
}
TargetPassConfig::addIRPasses();
}
bool PPCPassConfig::addPreISel() {
if (!DisablePreIncPrep && getOptLevel() != CodeGenOpt::None)
addPass(createPPCLoopPreIncPrepPass(getPPCTargetMachine()));
if (!DisableCTRLoops && getOptLevel() != CodeGenOpt::None)
addPass(createPPCCTRLoops());
return false;
}
bool PPCPassConfig::addILPOpts() {
addPass(&EarlyIfConverterID);
if (EnableMachineCombinerPass)
addPass(&MachineCombinerID);
return true;
}
bool PPCPassConfig::addInstSelector() {
// Install an instruction selector.
addPass(createPPCISelDag(getPPCTargetMachine(), getOptLevel()));
#ifndef NDEBUG
if (!DisableCTRLoops && getOptLevel() != CodeGenOpt::None)
addPass(createPPCCTRLoopsVerify());
#endif
addPass(createPPCVSXCopyPass());
return false;
}
void PPCPassConfig::addMachineSSAOptimization() {
// PPCBranchCoalescingPass need to be done before machine sinking
// since it merges empty blocks.
if (EnableBranchCoalescing && getOptLevel() != CodeGenOpt::None)
addPass(createPPCBranchCoalescingPass());
TargetPassConfig::addMachineSSAOptimization();
// For little endian, remove where possible the vector swap instructions
// introduced at code generation to normalize vector element order.
if (TM->getTargetTriple().getArch() == Triple::ppc64le &&
!DisableVSXSwapRemoval)
addPass(createPPCVSXSwapRemovalPass());
// Reduce the number of cr-logical ops.
if (ReduceCRLogical && getOptLevel() != CodeGenOpt::None)
addPass(createPPCReduceCRLogicalsPass());
// Target-specific peephole cleanups performed after instruction
// selection.
if (!DisableMIPeephole) {
addPass(createPPCMIPeepholePass());
addPass(&DeadMachineInstructionElimID);
}
}
void PPCPassConfig::addPreRegAlloc() {
if (getOptLevel() != CodeGenOpt::None) {
initializePPCVSXFMAMutatePass(*PassRegistry::getPassRegistry());
insertPass(VSXFMAMutateEarly ? &RegisterCoalescerID : &MachineSchedulerID,
&PPCVSXFMAMutateID);
}
// FIXME: We probably don't need to run these for -fPIE.
if (getPPCTargetMachine().isPositionIndependent()) {
// FIXME: LiveVariables should not be necessary here!
// PPCTLSDynamicCallPass uses LiveIntervals which previously dependent on
// LiveVariables. This (unnecessary) dependency has been removed now,
// however a stage-2 clang build fails without LiveVariables computed here.
addPass(&LiveVariablesID, false);
addPass(createPPCTLSDynamicCallPass());
}
if (EnableExtraTOCRegDeps)
addPass(createPPCTOCRegDepsPass());
}
void PPCPassConfig::addPreSched2() {
if (getOptLevel() != CodeGenOpt::None) {
addPass(&IfConverterID);
// This optimization must happen after anything that might do store-to-load
// forwarding. Here we're after RA (and, thus, when spills are inserted)
// but before post-RA scheduling.
if (!DisableQPXLoadSplat)
addPass(createPPCQPXLoadSplatPass());
}
}
void PPCPassConfig::addPreEmitPass() {
addPass(createPPCPreEmitPeepholePass());
addPass(createPPCExpandISELPass());
if (getOptLevel() != CodeGenOpt::None)
addPass(createPPCEarlyReturnPass(), false);
// Must run branch selection immediately preceding the asm printer.
addPass(createPPCBranchSelectionPass(), false);
}
TargetTransformInfo
PPCTargetMachine::getTargetTransformInfo(const Function &F) {
return TargetTransformInfo(PPCTTIImpl(this, F));
}
static MachineSchedRegistry
PPCPreRASchedRegistry("ppc-prera",
"Run PowerPC PreRA specific scheduler",
createPPCMachineScheduler);
static MachineSchedRegistry
PPCPostRASchedRegistry("ppc-postra",
"Run PowerPC PostRA specific scheduler",
createPPCPostMachineScheduler);
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