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//===-- llvm/Target/TargetMachine.h - Target Information --------*- C++ -*-===//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
// This file defines the TargetMachine and LLVMTargetMachine classes.
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/Triple.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/Pass.h"
#include "llvm/Support/CodeGen.h"
#include "llvm/Target/TargetOptions.h"
#include <string>
namespace llvm {
class Function;
class GlobalValue;
class MachineModuleInfoWrapperPass;
class Mangler;
class MCAsmInfo;
class MCContext;
class MCInstrInfo;
class MCRegisterInfo;
class MCSubtargetInfo;
class MCSymbol;
class raw_pwrite_stream;
class PassManagerBuilder;
struct PerFunctionMIParsingState;
class SMDiagnostic;
class SMRange;
class Target;
class TargetIntrinsicInfo;
class TargetIRAnalysis;
class TargetTransformInfo;
class TargetLoweringObjectFile;
class TargetPassConfig;
class TargetSubtargetInfo;
// The old pass manager infrastructure is hidden in a legacy namespace now.
namespace legacy {
class PassManagerBase;
using legacy::PassManagerBase;
namespace yaml {
struct MachineFunctionInfo;
/// Primary interface to the complete machine description for the target
/// machine. All target-specific information should be accessible through this
/// interface.
class TargetMachine {
protected: // Can only create subclasses.
TargetMachine(const Target &T, StringRef DataLayoutString,
const Triple &TargetTriple, StringRef CPU, StringRef FS,
const TargetOptions &Options);
/// The Target that this machine was created for.
const Target &TheTarget;
/// DataLayout for the target: keep ABI type size and alignment.
/// The DataLayout is created based on the string representation provided
/// during construction. It is kept here only to avoid reparsing the string
/// but should not really be used during compilation, because it has an
/// internal cache that is context specific.
const DataLayout DL;
/// Triple string, CPU name, and target feature strings the TargetMachine
/// instance is created with.
Triple TargetTriple;
std::string TargetCPU;
std::string TargetFS;
Reloc::Model RM = Reloc::Static;
CodeModel::Model CMModel = CodeModel::Small;
CodeGenOpt::Level OptLevel = CodeGenOpt::Default;
/// Contains target specific asm information.
std::unique_ptr<const MCAsmInfo> AsmInfo;
std::unique_ptr<const MCRegisterInfo> MRI;
std::unique_ptr<const MCInstrInfo> MII;
std::unique_ptr<const MCSubtargetInfo> STI;
unsigned RequireStructuredCFG : 1;
unsigned O0WantsFastISel : 1;
const TargetOptions DefaultOptions;
mutable TargetOptions Options;
TargetMachine(const TargetMachine &) = delete;
void operator=(const TargetMachine &) = delete;
virtual ~TargetMachine();
const Target &getTarget() const { return TheTarget; }
const Triple &getTargetTriple() const { return TargetTriple; }
StringRef getTargetCPU() const { return TargetCPU; }
StringRef getTargetFeatureString() const { return TargetFS; }
/// Virtual method implemented by subclasses that returns a reference to that
/// target's TargetSubtargetInfo-derived member variable.
virtual const TargetSubtargetInfo *getSubtargetImpl(const Function &) const {
return nullptr;
virtual TargetLoweringObjectFile *getObjFileLowering() const {
return nullptr;
/// Allocate and return a default initialized instance of the YAML
/// representation for the MachineFunctionInfo.
virtual yaml::MachineFunctionInfo *createDefaultFuncInfoYAML() const {
return nullptr;
/// Allocate and initialize an instance of the YAML representation of the
/// MachineFunctionInfo.
virtual yaml::MachineFunctionInfo *
convertFuncInfoToYAML(const MachineFunction &MF) const {
return nullptr;
/// Parse out the target's MachineFunctionInfo from the YAML reprsentation.
virtual bool parseMachineFunctionInfo(const yaml::MachineFunctionInfo &,
PerFunctionMIParsingState &PFS,
SMDiagnostic &Error,
SMRange &SourceRange) const {
return false;
/// This method returns a pointer to the specified type of
/// TargetSubtargetInfo. In debug builds, it verifies that the object being
/// returned is of the correct type.
template <typename STC> const STC &getSubtarget(const Function &F) const {
return *static_cast<const STC*>(getSubtargetImpl(F));
/// Create a DataLayout.
const DataLayout createDataLayout() const { return DL; }
/// Test if a DataLayout if compatible with the CodeGen for this target.
/// The LLVM Module owns a DataLayout that is used for the target independent
/// optimizations and code generation. This hook provides a target specific
/// check on the validity of this DataLayout.
bool isCompatibleDataLayout(const DataLayout &Candidate) const {
return DL == Candidate;
/// Get the pointer size for this target.
/// This is the only time the DataLayout in the TargetMachine is used.
unsigned getPointerSize(unsigned AS) const {
return DL.getPointerSize(AS);
unsigned getPointerSizeInBits(unsigned AS) const {
return DL.getPointerSizeInBits(AS);
unsigned getProgramPointerSize() const {
return DL.getPointerSize(DL.getProgramAddressSpace());
unsigned getAllocaPointerSize() const {
return DL.getPointerSize(DL.getAllocaAddrSpace());
/// Reset the target options based on the function's attributes.
// FIXME: Remove TargetOptions that affect per-function code generation
// from TargetMachine.
void resetTargetOptions(const Function &F) const;
/// Return target specific asm information.
const MCAsmInfo *getMCAsmInfo() const { return AsmInfo.get(); }
const MCRegisterInfo *getMCRegisterInfo() const { return MRI.get(); }
const MCInstrInfo *getMCInstrInfo() const { return MII.get(); }
const MCSubtargetInfo *getMCSubtargetInfo() const { return STI.get(); }
/// If intrinsic information is available, return it. If not, return null.
virtual const TargetIntrinsicInfo *getIntrinsicInfo() const {
return nullptr;
bool requiresStructuredCFG() const { return RequireStructuredCFG; }
void setRequiresStructuredCFG(bool Value) { RequireStructuredCFG = Value; }
/// Returns the code generation relocation model. The choices are static, PIC,
/// and dynamic-no-pic, and target default.
Reloc::Model getRelocationModel() const;
/// Returns the code model. The choices are small, kernel, medium, large, and
/// target default.
CodeModel::Model getCodeModel() const;
bool isPositionIndependent() const;
bool shouldAssumeDSOLocal(const Module &M, const GlobalValue *GV) const;
/// Returns true if this target uses emulated TLS.
bool useEmulatedTLS() const;
/// Returns the TLS model which should be used for the given global variable.
TLSModel::Model getTLSModel(const GlobalValue *GV) const;
/// Returns the optimization level: None, Less, Default, or Aggressive.
CodeGenOpt::Level getOptLevel() const;
/// Overrides the optimization level.
void setOptLevel(CodeGenOpt::Level Level);
void setFastISel(bool Enable) { Options.EnableFastISel = Enable; }
bool getO0WantsFastISel() { return O0WantsFastISel; }
void setO0WantsFastISel(bool Enable) { O0WantsFastISel = Enable; }
void setGlobalISel(bool Enable) { Options.EnableGlobalISel = Enable; }
void setGlobalISelAbort(GlobalISelAbortMode Mode) {
Options.GlobalISelAbort = Mode;
void setMachineOutliner(bool Enable) {
Options.EnableMachineOutliner = Enable;
void setSupportsDefaultOutlining(bool Enable) {
Options.SupportsDefaultOutlining = Enable;
bool shouldPrintMachineCode() const { return Options.PrintMachineCode; }
bool getUniqueSectionNames() const { return Options.UniqueSectionNames; }
/// Return true if data objects should be emitted into their own section,
/// corresponds to -fdata-sections.
bool getDataSections() const {
return Options.DataSections;
/// Return true if functions should be emitted into their own section,
/// corresponding to -ffunction-sections.
bool getFunctionSections() const {
return Options.FunctionSections;
/// Get a \c TargetIRAnalysis appropriate for the target.
/// This is used to construct the new pass manager's target IR analysis pass,
/// set up appropriately for this target machine. Even the old pass manager
/// uses this to answer queries about the IR.
TargetIRAnalysis getTargetIRAnalysis();
/// Return a TargetTransformInfo for a given function.
/// The returned TargetTransformInfo is specialized to the subtarget
/// corresponding to \p F.
virtual TargetTransformInfo getTargetTransformInfo(const Function &F);
/// Allow the target to modify the pass manager, e.g. by calling
/// PassManagerBuilder::addExtension.
virtual void adjustPassManager(PassManagerBuilder &) {}
/// These enums are meant to be passed into addPassesToEmitFile to indicate
/// what type of file to emit, and returned by it to indicate what type of
/// file could actually be made.
enum CodeGenFileType {
CGFT_Null // Do not emit any output.
/// Add passes to the specified pass manager to get the specified file
/// emitted. Typically this will involve several steps of code generation.
/// This method should return true if emission of this file type is not
/// supported, or false on success.
/// \p MMIWP is an optional parameter that, if set to non-nullptr,
/// will be used to set the MachineModuloInfo for this PM.
virtual bool
addPassesToEmitFile(PassManagerBase &, raw_pwrite_stream &,
raw_pwrite_stream *, CodeGenFileType,
bool /*DisableVerify*/ = true,
MachineModuleInfoWrapperPass *MMIWP = nullptr) {
return true;
/// Add passes to the specified pass manager to get machine code emitted with
/// the MCJIT. This method returns true if machine code is not supported. It
/// fills the MCContext Ctx pointer which can be used to build custom
/// MCStreamer.
virtual bool addPassesToEmitMC(PassManagerBase &, MCContext *&,
raw_pwrite_stream &,
bool /*DisableVerify*/ = true) {
return true;
/// True if subtarget inserts the final scheduling pass on its own.
/// Branch relaxation, which must happen after block placement, can
/// on some targets (e.g. SystemZ) expose additional post-RA
/// scheduling opportunities.
virtual bool targetSchedulesPostRAScheduling() const { return false; };
void getNameWithPrefix(SmallVectorImpl<char> &Name, const GlobalValue *GV,
Mangler &Mang, bool MayAlwaysUsePrivate = false) const;
MCSymbol *getSymbol(const GlobalValue *GV) const;
/// This class describes a target machine that is implemented with the LLVM
/// target-independent code generator.
class LLVMTargetMachine : public TargetMachine {
protected: // Can only create subclasses.
LLVMTargetMachine(const Target &T, StringRef DataLayoutString,
const Triple &TT, StringRef CPU, StringRef FS,
const TargetOptions &Options, Reloc::Model RM,
CodeModel::Model CM, CodeGenOpt::Level OL);
void initAsmInfo();
/// Get a TargetTransformInfo implementation for the target.
/// The TTI returned uses the common code generator to answer queries about
/// the IR.
TargetTransformInfo getTargetTransformInfo(const Function &F) override;
/// Create a pass configuration object to be used by addPassToEmitX methods
/// for generating a pipeline of CodeGen passes.
virtual TargetPassConfig *createPassConfig(PassManagerBase &PM);
/// Add passes to the specified pass manager to get the specified file
/// emitted. Typically this will involve several steps of code generation.
/// \p MMIWP is an optional parameter that, if set to non-nullptr,
/// will be used to set the MachineModuloInfo for this PM.
addPassesToEmitFile(PassManagerBase &PM, raw_pwrite_stream &Out,
raw_pwrite_stream *DwoOut, CodeGenFileType FileType,
bool DisableVerify = true,
MachineModuleInfoWrapperPass *MMIWP = nullptr) override;
/// Add passes to the specified pass manager to get machine code emitted with
/// the MCJIT. This method returns true if machine code is not supported. It
/// fills the MCContext Ctx pointer which can be used to build custom
/// MCStreamer.
bool addPassesToEmitMC(PassManagerBase &PM, MCContext *&Ctx,
raw_pwrite_stream &Out,
bool DisableVerify = true) override;
/// Returns true if the target is expected to pass all machine verifier
/// checks. This is a stopgap measure to fix targets one by one. We will
/// remove this at some point and always enable the verifier when
/// EXPENSIVE_CHECKS is enabled.
virtual bool isMachineVerifierClean() const { return true; }
/// Adds an AsmPrinter pass to the pipeline that prints assembly or
/// machine code from the MI representation.
bool addAsmPrinter(PassManagerBase &PM, raw_pwrite_stream &Out,
raw_pwrite_stream *DwoOut, CodeGenFileType FileType,
MCContext &Context);
/// True if the target uses physical regs at Prolog/Epilog insertion
/// time. If true (most machines), all vregs must be allocated before
/// PEI. If false (virtual-register machines), then callee-save register
/// spilling and scavenging are not needed or used.
virtual bool usesPhysRegsForPEI() const { return true; }
/// True if the target wants to use interprocedural register allocation by
/// default. The -enable-ipra flag can be used to override this.
virtual bool useIPRA() const {
return false;
/// Helper method for getting the code model, returning Default if
/// CM does not have a value. The tiny and kernel models will produce
/// an error, so targets that support them or require more complex codemodel
/// selection logic should implement and call their own getEffectiveCodeModel.
inline CodeModel::Model getEffectiveCodeModel(Optional<CodeModel::Model> CM,
CodeModel::Model Default) {
if (CM) {
// By default, targets do not support the tiny and kernel models.
if (*CM == CodeModel::Tiny)
report_fatal_error("Target does not support the tiny CodeModel", false);
if (*CM == CodeModel::Kernel)
report_fatal_error("Target does not support the kernel CodeModel", false);
return *CM;
return Default;
} // end namespace llvm