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//===-- PPCTargetMachine.cpp - Define TargetMachine for PowerPC -----------===//
// The LLVM Compiler Infrastructure
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
// Top-level implementation for the PowerPC target.
#include "PPCTargetMachine.h"
#include "PPC.h"
#include "PPCTargetObjectFile.h"
#include "PPCTargetTransformInfo.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/LegacyPassManager.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/FormattedStream.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/Transforms/Scalar.h"
using namespace llvm;
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>
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> 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"),
static cl::opt<bool>
cl::desc("disable software prefetching on PPC"),
cl::init(false), cl::Hidden);
static cl::opt<bool>
cl::desc("Add extra TOC register dependencies"),
cl::init(true), cl::Hidden);
static cl::opt<bool>
cl::desc("Enable the machine combiner pass"),
cl::init(true), cl::Hidden);
extern "C" void LLVMInitializePowerPCTarget() {
// Register the targets
RegisterTargetMachine<PPC32TargetMachine> A(ThePPC32Target);
RegisterTargetMachine<PPC64TargetMachine> B(ThePPC64Target);
RegisterTargetMachine<PPC64TargetMachine> C(ThePPC64LETarget);
PassRegistry &PR = *PassRegistry::getPassRegistry();
/// 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";
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";
Ret += "-f64:32:64";
// PPC64 has 32 and 64 bit registers, PPC32 has only 32 bit ones.
if (is64Bit)
Ret += "-n32:64";
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;
FullFS = "+64bit";
if (OL >= CodeGenOpt::Default) {
if (!FullFS.empty())
FullFS = "+crbits," + FullFS;
FullFS = "+crbits";
if (OL != CodeGenOpt::None) {
if (!FullFS.empty())
FullFS = "+invariant-function-descriptors," + FullFS;
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 make_unique<TargetLoweringObjectFileMachO>();
return make_unique<PPC64LinuxTargetObjectFile>();
static PPCTargetMachine::PPCABI computeTargetABI(const Triple &TT,
const TargetOptions &Options) {
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()) {
switch (TT.getArch()) {
case Triple::ppc64le:
return PPCTargetMachine::PPC_ABI_ELFv2;
case Triple::ppc64:
return PPCTargetMachine::PPC_ABI_ELFv1;
// Fallthrough.
return PPCTargetMachine::PPC_ABI_UNKNOWN;
// 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,
Reloc::Model RM, CodeModel::Model CM,
CodeGenOpt::Level OL)
: LLVMTargetMachine(T, getDataLayoutString(TT), TT, CPU,
computeFSAdditions(FS, OL, TT), Options, RM, CM, OL),
TargetABI(computeTargetABI(TT, Options)),
Subtarget(TargetTriple, CPU, computeFSAdditions(FS, OL, TT), *this) {
// For the estimates, convergence is quadratic, so we essentially double the
// number of digits correct after every iteration. For both FRE and FRSQRTE,
// the minimum architected relative accuracy is 2^-5. When hasRecipPrec(),
// this is 2^-14. IEEE float has 23 digits and double has 52 digits.
unsigned RefinementSteps = Subtarget.hasRecipPrec() ? 1 : 3,
RefinementSteps64 = RefinementSteps + 1;
this->Options.Reciprocals.setDefaults("sqrtf", true, RefinementSteps);
this->Options.Reciprocals.setDefaults("vec-sqrtf", true, RefinementSteps);
this->Options.Reciprocals.setDefaults("divf", true, RefinementSteps);
this->Options.Reciprocals.setDefaults("vec-divf", true, RefinementSteps);
this->Options.Reciprocals.setDefaults("sqrtd", true, RefinementSteps64);
this->Options.Reciprocals.setDefaults("vec-sqrtd", true, RefinementSteps64);
this->Options.Reciprocals.setDefaults("divd", true, RefinementSteps64);
this->Options.Reciprocals.setDefaults("vec-divd", true, RefinementSteps64);
PPCTargetMachine::~PPCTargetMachine() {}
void PPC32TargetMachine::anchor() { }
PPC32TargetMachine::PPC32TargetMachine(const Target &T, const Triple &TT,
StringRef CPU, StringRef FS,
const TargetOptions &Options,
Reloc::Model RM, CodeModel::Model CM,
CodeGenOpt::Level OL)
: PPCTargetMachine(T, TT, CPU, FS, Options, RM, CM, OL) {}
void PPC64TargetMachine::anchor() { }
PPC64TargetMachine::PPC64TargetMachine(const Target &T, const Triple &TT,
StringRef CPU, StringRef FS,
const TargetOptions &Options,
Reloc::Model RM, CodeModel::Model CM,
CodeGenOpt::Level OL)
: PPCTargetMachine(T, TT, CPU, FS, Options, RM, CM, OL) {}
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.hasFnAttribute("use-soft-float") &&
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() ? "+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.
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 {
PPCPassConfig(PPCTargetMachine *TM, PassManagerBase &PM)
: TargetPassConfig(TM, PM) {}
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;
} // namespace
TargetPassConfig *PPCTargetMachine::createPassConfig(PassManagerBase &PM) {
return new PPCPassConfig(this, PM);
void PPCPassConfig::addIRPasses() {
if (TM->getOptLevel() != CodeGenOpt::None)
// 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)
if (TM->getOptLevel() == CodeGenOpt::Aggressive && 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(TM, true));
// Call EarlyCSE pass to find and remove subexpressions in the lowered
// result.
// Do loop invariant code motion in case part of the lowered result is
// invariant.
bool PPCPassConfig::addPreISel() {
if (!DisablePreIncPrep && getOptLevel() != CodeGenOpt::None)
if (!DisableCTRLoops && getOptLevel() != CodeGenOpt::None)
return false;
bool PPCPassConfig::addILPOpts() {
if (EnableMachineCombinerPass)
return true;
bool PPCPassConfig::addInstSelector() {
// Install an instruction selector.
#ifndef NDEBUG
if (!DisableCTRLoops && getOptLevel() != CodeGenOpt::None)
return false;
void PPCPassConfig::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 &&
// Target-specific peephole cleanups performed after instruction
// selection.
if (!DisableMIPeephole) {
void PPCPassConfig::addPreRegAlloc() {
insertPass(VSXFMAMutateEarly ? &RegisterCoalescerID : &MachineSchedulerID,
if (getPPCTargetMachine().getRelocationModel() == Reloc::PIC_)
if (EnableExtraTOCRegDeps)
void PPCPassConfig::addPreSched2() {
if (getOptLevel() != CodeGenOpt::None)
void PPCPassConfig::addPreEmitPass() {
if (getOptLevel() != CodeGenOpt::None)
addPass(createPPCEarlyReturnPass(), false);
// Must run branch selection immediately preceding the asm printer.
addPass(createPPCBranchSelectionPass(), false);
TargetIRAnalysis PPCTargetMachine::getTargetIRAnalysis() {
return TargetIRAnalysis([this](const Function &F) {
return TargetTransformInfo(PPCTTIImpl(this, F));