LLVM 18.0.0git
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1//===-- TargetMachine.cpp - General Target Information ---------------------==//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
9// This file describes the general parts of a Target machine.
15#include "llvm/IR/Function.h"
16#include "llvm/IR/GlobalValue.h"
18#include "llvm/IR/Mangler.h"
19#include "llvm/MC/MCAsmInfo.h"
20#include "llvm/MC/MCContext.h"
21#include "llvm/MC/MCInstrInfo.h"
26using namespace llvm;
29// TargetMachine Class
33 const Triple &TT, StringRef CPU, StringRef FS,
35 : TheTarget(T), DL(DataLayoutString), TargetTriple(TT),
36 TargetCPU(std::string(CPU)), TargetFS(std::string(FS)), AsmInfo(nullptr),
37 MRI(nullptr), MII(nullptr), STI(nullptr), RequireStructuredCFG(false),
38 O0WantsFastISel(false), Options(Options) {}
43 if (getTargetTriple().getArch() != Triple::x86_64)
44 return false;
45 // Large data under the large code model still needs to be thought about, so
46 // restrict this to medium.
48 return false;
49 const DataLayout &DL = GV->getParent()->getDataLayout();
51 return Size == 0 || Size > LargeDataThreshold;
58/// Reset the target options based on the function's attributes.
59/// setFunctionAttributes should have made the raw attribute value consistent
60/// with the command line flag if used.
62// FIXME: This function needs to go away for a number of reasons:
63// a) global state on the TargetMachine is terrible in general,
64// b) these target options should be passed only on the function
65// and not on the TargetMachine (via TargetOptions) at all.
67#define RESET_OPTION(X, Y) \
68 do { \
69 Options.X = F.getFnAttribute(Y).getValueAsBool(); \
70 } while (0)
72 RESET_OPTION(UnsafeFPMath, "unsafe-fp-math");
73 RESET_OPTION(NoInfsFPMath, "no-infs-fp-math");
74 RESET_OPTION(NoNaNsFPMath, "no-nans-fp-math");
75 RESET_OPTION(NoSignedZerosFPMath, "no-signed-zeros-fp-math");
76 RESET_OPTION(ApproxFuncFPMath, "approx-func-fp-math");
79/// Returns the code generation relocation model. The choices are static, PIC,
80/// and dynamic-no-pic.
84 switch (getCodeModel()) {
85 case CodeModel::Tiny:
86 return llvm::maxUIntN(10);
90 return llvm::maxUIntN(31);
92 return llvm::maxUIntN(64);
93 }
94 llvm_unreachable("Unhandled CodeModel enum");
97/// Get the IR-specified TLS model for Var.
99 switch (GV->getThreadLocalMode()) {
101 llvm_unreachable("getSelectedTLSModel for non-TLS variable");
102 break;
110 return TLSModel::LocalExec;
111 }
112 llvm_unreachable("invalid TLS model");
116 const GlobalValue *GV) const {
117 const Triple &TT = getTargetTriple();
120 // According to the llvm language reference, we should be able to
121 // just return false in here if we have a GV, as we know it is
122 // dso_preemptable. At this point in time, the various IR producers
123 // have not been transitioned to always produce a dso_local when it
124 // is possible to do so.
125 //
126 // As a result we still have some logic in here to improve the quality of the
127 // generated code.
128 if (!GV)
129 return false;
131 // If the IR producer requested that this GV be treated as dso local, obey.
132 if (GV->isDSOLocal())
133 return true;
135 if (TT.isOSBinFormatCOFF()) {
136 // DLLImport explicitly marks the GV as external.
137 if (GV->hasDLLImportStorageClass())
138 return false;
140 // On MinGW, variables that haven't been declared with DLLImport may still
141 // end up automatically imported by the linker. To make this feasible,
142 // don't assume the variables to be DSO local unless we actually know
143 // that for sure. This only has to be done for variables; for functions
144 // the linker can insert thunks for calling functions from another DLL.
145 if (TT.isWindowsGNUEnvironment() && GV->isDeclarationForLinker() &&
146 isa<GlobalVariable>(GV))
147 return false;
149 // Don't mark 'extern_weak' symbols as DSO local. If these symbols remain
150 // unresolved in the link, they can be resolved to zero, which is outside
151 // the current DSO.
152 if (GV->hasExternalWeakLinkage())
153 return false;
155 // Every other GV is local on COFF.
156 return true;
157 }
159 if (TT.isOSBinFormatGOFF())
160 return true;
162 if (TT.isOSBinFormatMachO()) {
163 if (RM == Reloc::Static)
164 return true;
165 return GV->isStrongDefinitionForLinker();
166 }
168 assert(TT.isOSBinFormatELF() || TT.isOSBinFormatWasm() ||
169 TT.isOSBinFormatXCOFF());
170 return false;
176 bool IsPIE = GV->getParent()->getPIELevel() != PIELevel::Default;
178 bool IsSharedLibrary = RM == Reloc::PIC_ && !IsPIE;
179 bool IsLocal = shouldAssumeDSOLocal(*GV->getParent(), GV);
181 TLSModel::Model Model;
182 if (IsSharedLibrary) {
183 if (IsLocal)
185 else
187 } else {
188 if (IsLocal)
189 Model = TLSModel::LocalExec;
190 else
191 Model = TLSModel::InitialExec;
192 }
194 // If the user specified a more specific model, use that.
195 TLSModel::Model SelectedModel = getSelectedTLSModel(GV);
196 if (SelectedModel > Model)
197 return SelectedModel;
199 return Model;
202/// Returns the optimization level: None, Less, Default, or Aggressive.
209 return TargetTransformInfo(F.getParent()->getDataLayout());
213 const GlobalValue *GV, Mangler &Mang,
214 bool MayAlwaysUsePrivate) const {
215 if (MayAlwaysUsePrivate || !GV->hasPrivateLinkage()) {
216 // Simple case: If GV is not private, it is not important to find out if
217 // private labels are legal in this case or not.
218 Mang.getNameWithPrefix(Name, GV, false);
219 return;
220 }
222 TLOF->getNameWithPrefix(Name, GV, *this);
227 // XCOFF symbols could have special naming convention.
228 if (MCSymbol *TargetSymbol = TLOF->getTargetSymbol(GV, *this))
229 return TargetSymbol;
231 SmallString<128> NameStr;
232 getNameWithPrefix(NameStr, GV, TLOF->getMangler());
233 return TLOF->getContext().getOrCreateSymbol(NameStr);
237 // Since Analysis can't depend on Target, use a std::function to invert the
238 // dependency.
239 return TargetIRAnalysis(
240 [this](const Function &F) { return this->getTargetTransformInfo(F); });
243std::pair<int, int> TargetMachine::parseBinutilsVersion(StringRef Version) {
244 if (Version == "none")
245 return {INT_MAX, INT_MAX}; // Make binutilsIsAtLeast() return true.
246 std::pair<int, int> Ret;
247 if (!Version.consumeInteger(10, Ret.first) && Version.consume_front("."))
248 Version.consumeInteger(10, Ret.second);
249 return Ret;
unsigned const MachineRegisterInfo * MRI
MachineBasicBlock MachineBasicBlock::iterator DebugLoc DL
std::string Name
uint64_t Size
static LVOptions Options
Definition: LVOptions.cpp:25
#define F(x, y, z)
Definition: MD5.cpp:55
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
static TLSModel::Model getSelectedTLSModel(const GlobalValue *GV)
Get the IR-specified TLS model for Var.
#define RESET_OPTION(X, Y)
This pass exposes codegen information to IR-level passes.
A parsed version of the target data layout string in and methods for querying it.
Definition: DataLayout.h:110
TypeSize getTypeSizeInBits(Type *Ty) const
Size examples:
Definition: DataLayout.h:672
bool isDSOLocal() const
Definition: GlobalValue.h:301
bool hasPrivateLinkage() const
Definition: GlobalValue.h:522
bool hasExternalWeakLinkage() const
Definition: GlobalValue.h:524
ThreadLocalMode getThreadLocalMode() const
Definition: GlobalValue.h:267
bool hasDLLImportStorageClass() const
Definition: GlobalValue.h:274
bool isDeclarationForLinker() const
Definition: GlobalValue.h:614
Module * getParent()
Get the module that this global value is contained inside of...
Definition: GlobalValue.h:652
bool isStrongDefinitionForLinker() const
Returns true if this global's definition will be the one chosen by the linker.
Definition: GlobalValue.h:627
Type * getValueType() const
Definition: GlobalValue.h:292
MCSymbol * getOrCreateSymbol(const Twine &Name)
Lookup the symbol inside with the specified Name.
Definition: MCContext.cpp:201
MCContext & getContext() const
MCSymbol - Instances of this class represent a symbol name in the MC file, and MCSymbols are created ...
Definition: MCSymbol.h:41
void getNameWithPrefix(raw_ostream &OS, const GlobalValue *GV, bool CannotUsePrivateLabel) const
Print the appropriate prefix and the specified global variable's name.
Definition: Mangler.cpp:119
A Module instance is used to store all the information related to an LLVM module.
Definition: Module.h:65
const DataLayout & getDataLayout() const
Get the data layout for the module's target platform.
Definition: Module.h:254
PIELevel::Level getPIELevel() const
Returns the PIE level (small or large model)
Definition: Module.cpp:602
SmallString - A SmallString is just a SmallVector with methods and accessors that make it work better...
Definition: SmallString.h:26
This class consists of common code factored out of the SmallVector class to reduce code duplication b...
Definition: SmallVector.h:577
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:50
Analysis pass providing the TargetTransformInfo.
virtual void getNameWithPrefix(SmallVectorImpl< char > &OutName, const GlobalValue *GV, const TargetMachine &TM) const
virtual MCSymbol * getTargetSymbol(const GlobalValue *GV, const TargetMachine &TM) const
Targets that have a special convention for their symbols could use this hook to return a specialized ...
TLSModel::Model getTLSModel(const GlobalValue *GV) const
Returns the TLS model which should be used for the given global variable.
bool isPositionIndependent() const
uint64_t getMaxCodeSize() const
Returns the maximum code size possible under the code model.
const Triple & getTargetTriple() const
uint64_t LargeDataThreshold
bool useEmulatedTLS() const
Returns true if this target uses emulated TLS.
bool isLargeData(const GlobalVariable *GV) const
virtual TargetLoweringObjectFile * getObjFileLowering() const
Reloc::Model getRelocationModel() const
Returns the code generation relocation model.
virtual TargetTransformInfo getTargetTransformInfo(const Function &F) const
Return a TargetTransformInfo for a given function.
const DataLayout DL
DataLayout for the target: keep ABI type size and alignment.
Definition: TargetMachine.h:93
static std::pair< int, int > parseBinutilsVersion(StringRef Version)
TargetIRAnalysis getTargetIRAnalysis() const
Get a TargetIRAnalysis appropriate for the target.
TargetOptions Options
virtual ~TargetMachine()
MCSymbol * getSymbol(const GlobalValue *GV) const
bool shouldAssumeDSOLocal(const Module &M, const GlobalValue *GV) const
CodeModel::Model getCodeModel() const
Returns the code model.
void resetTargetOptions(const Function &F) const
Reset the target options based on the function's attributes.
TargetMachine(const Target &T, StringRef DataLayoutString, const Triple &TargetTriple, StringRef CPU, StringRef FS, const TargetOptions &Options)
void getNameWithPrefix(SmallVectorImpl< char > &Name, const GlobalValue *GV, Mangler &Mang, bool MayAlwaysUsePrivate=false) const
CodeGenOptLevel getOptLevel() const
Returns the optimization level: None, Less, Default, or Aggressive.
CodeGenOptLevel OptLevel
void setOptLevel(CodeGenOptLevel Level)
Overrides the optimization level.
unsigned EmulatedTLS
EmulatedTLS - This flag enables emulated TLS model, using emutls function in the runtime library.
This pass provides access to the codegen interfaces that are needed for IR-level transformations.
Target - Wrapper for Target specific information.
Triple - Helper class for working with autoconf configuration names.
Definition: Triple.h:44
#define llvm_unreachable(msg)
Marks that the current location is not supposed to be reachable.
@ GeneralDynamic
Definition: CodeGen.h:46
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:18
Code generation optimization level.
Definition: CodeGen.h:54
uint64_t maxUIntN(uint64_t N)
Gets the maximum value for a N-bit unsigned integer.
Definition: MathExtras.h:201
Implement std::hash so that hash_code can be used in STL containers.
Definition: BitVector.h:858