LLVM  14.0.0git
TargetMachine.cpp
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1 //===-- TargetMachine.cpp - General Target Information ---------------------==//
2 //
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
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file describes the general parts of a Target machine.
10 //
11 //===----------------------------------------------------------------------===//
12 
15 #include "llvm/IR/Function.h"
16 #include "llvm/IR/GlobalAlias.h"
17 #include "llvm/IR/GlobalValue.h"
18 #include "llvm/IR/GlobalVariable.h"
20 #include "llvm/IR/Mangler.h"
21 #include "llvm/MC/MCAsmInfo.h"
22 #include "llvm/MC/MCContext.h"
23 #include "llvm/MC/MCInstrInfo.h"
24 #include "llvm/MC/MCSectionMachO.h"
26 #include "llvm/MC/SectionKind.h"
28 using namespace llvm;
29 
30 //---------------------------------------------------------------------------
31 // TargetMachine Class
32 //
33 
35  const Triple &TT, StringRef CPU, StringRef FS,
36  const TargetOptions &Options)
37  : TheTarget(T), DL(DataLayoutString), TargetTriple(TT),
38  TargetCPU(std::string(CPU)), TargetFS(std::string(FS)), AsmInfo(nullptr),
39  MRI(nullptr), MII(nullptr), STI(nullptr), RequireStructuredCFG(false),
40  O0WantsFastISel(false), DefaultOptions(Options), Options(Options) {}
41 
43 
45  return getRelocationModel() == Reloc::PIC_;
46 }
47 
48 /// Reset the target options based on the function's attributes.
49 /// setFunctionAttributes should have made the raw attribute value consistent
50 /// with the command line flag if used.
51 //
52 // FIXME: This function needs to go away for a number of reasons:
53 // a) global state on the TargetMachine is terrible in general,
54 // b) these target options should be passed only on the function
55 // and not on the TargetMachine (via TargetOptions) at all.
57 #define RESET_OPTION(X, Y) \
58  do { \
59  Options.X = F.getFnAttribute(Y).getValueAsBool(); \
60  } while (0)
61 
62  RESET_OPTION(UnsafeFPMath, "unsafe-fp-math");
63  RESET_OPTION(NoInfsFPMath, "no-infs-fp-math");
64  RESET_OPTION(NoNaNsFPMath, "no-nans-fp-math");
65  RESET_OPTION(NoSignedZerosFPMath, "no-signed-zeros-fp-math");
66 }
67 
68 /// Returns the code generation relocation model. The choices are static, PIC,
69 /// and dynamic-no-pic.
71 
72 /// Returns the code model. The choices are small, kernel, medium, large, and
73 /// target default.
75 
76 /// Get the IR-specified TLS model for Var.
78  switch (GV->getThreadLocalMode()) {
80  llvm_unreachable("getSelectedTLSModel for non-TLS variable");
81  break;
87  return TLSModel::InitialExec;
89  return TLSModel::LocalExec;
90  }
91  llvm_unreachable("invalid TLS model");
92 }
93 
95  const GlobalValue *GV) const {
96  const Triple &TT = getTargetTriple();
98 
99  // According to the llvm language reference, we should be able to
100  // just return false in here if we have a GV, as we know it is
101  // dso_preemptable. At this point in time, the various IR producers
102  // have not been transitioned to always produce a dso_local when it
103  // is possible to do so.
104  //
105  // As a result we still have some logic in here to improve the quality of the
106  // generated code.
107  if (!GV)
108  return false;
109 
110  // If the IR producer requested that this GV be treated as dso local, obey.
111  if (GV->isDSOLocal())
112  return true;
113 
114  if (TT.isOSBinFormatCOFF()) {
115  // DLLImport explicitly marks the GV as external.
116  if (GV->hasDLLImportStorageClass())
117  return false;
118 
119  // On MinGW, variables that haven't been declared with DLLImport may still
120  // end up automatically imported by the linker. To make this feasible,
121  // don't assume the variables to be DSO local unless we actually know
122  // that for sure. This only has to be done for variables; for functions
123  // the linker can insert thunks for calling functions from another DLL.
124  if (TT.isWindowsGNUEnvironment() && GV->isDeclarationForLinker() &&
125  isa<GlobalVariable>(GV))
126  return false;
127 
128  // Don't mark 'extern_weak' symbols as DSO local. If these symbols remain
129  // unresolved in the link, they can be resolved to zero, which is outside
130  // the current DSO.
131  if (GV->hasExternalWeakLinkage())
132  return false;
133 
134  // Every other GV is local on COFF.
135  return true;
136  }
137 
138  if (TT.isOSBinFormatMachO()) {
139  if (RM == Reloc::Static)
140  return true;
141  return GV->isStrongDefinitionForLinker();
142  }
143 
144  assert(TT.isOSBinFormatELF() || TT.isOSBinFormatWasm() ||
145  TT.isOSBinFormatXCOFF());
146  return false;
147 }
148 
150  // Returns Options.EmulatedTLS if the -emulated-tls or -no-emulated-tls
151  // was specified explicitly; otherwise uses target triple to decide default.
153  return Options.EmulatedTLS;
155 }
156 
158  bool IsPIE = GV->getParent()->getPIELevel() != PIELevel::Default;
160  bool IsSharedLibrary = RM == Reloc::PIC_ && !IsPIE;
161  bool IsLocal = shouldAssumeDSOLocal(*GV->getParent(), GV);
162 
164  if (IsSharedLibrary) {
165  if (IsLocal)
167  else
169  } else {
170  if (IsLocal)
172  else
174  }
175 
176  // If the user specified a more specific model, use that.
177  TLSModel::Model SelectedModel = getSelectedTLSModel(GV);
178  if (SelectedModel > Model)
179  return SelectedModel;
180 
181  return Model;
182 }
183 
184 /// Returns the optimization level: None, Less, Default, or Aggressive.
186 
188 
190  return TargetTransformInfo(F.getParent()->getDataLayout());
191 }
192 
194  const GlobalValue *GV, Mangler &Mang,
195  bool MayAlwaysUsePrivate) const {
196  if (MayAlwaysUsePrivate || !GV->hasPrivateLinkage()) {
197  // Simple case: If GV is not private, it is not important to find out if
198  // private labels are legal in this case or not.
199  Mang.getNameWithPrefix(Name, GV, false);
200  return;
201  }
203  TLOF->getNameWithPrefix(Name, GV, *this);
204 }
205 
208  // XCOFF symbols could have special naming convention.
209  if (MCSymbol *TargetSymbol = TLOF->getTargetSymbol(GV, *this))
210  return TargetSymbol;
211 
212  SmallString<128> NameStr;
213  getNameWithPrefix(NameStr, GV, TLOF->getMangler());
214  return TLOF->getContext().getOrCreateSymbol(NameStr);
215 }
216 
218  // Since Analysis can't depend on Target, use a std::function to invert the
219  // dependency.
220  return TargetIRAnalysis(
221  [this](const Function &F) { return this->getTargetTransformInfo(F); });
222 }
223 
225  if (Version == "none")
226  return {INT_MAX, INT_MAX}; // Make binutilsIsAtLeast() return true.
227  std::pair<int, int> Ret;
228  if (!Version.consumeInteger(10, Ret.first) && Version.consume_front("."))
229  Version.consumeInteger(10, Ret.second);
230  return Ret;
231 }
llvm::TargetMachine::getOptLevel
CodeGenOpt::Level getOptLevel() const
Returns the optimization level: None, Less, Default, or Aggressive.
Definition: TargetMachine.cpp:185
llvm::TargetIRAnalysis
Analysis pass providing the TargetTransformInfo.
Definition: TargetTransformInfo.h:2331
llvm
This file implements support for optimizing divisions by a constant.
Definition: AllocatorList.h:23
llvm::MCSymbol
MCSymbol - Instances of this class represent a symbol name in the MC file, and MCSymbols are created ...
Definition: MCSymbol.h:41
llvm::TargetMachine::useEmulatedTLS
bool useEmulatedTLS() const
Returns true if this target uses emulated TLS.
Definition: TargetMachine.cpp:149
MCTargetOptions.h
llvm::TargetLoweringObjectFile::getNameWithPrefix
virtual void getNameWithPrefix(SmallVectorImpl< char > &OutName, const GlobalValue *GV, const TargetMachine &TM) const
Definition: TargetLoweringObjectFile.cpp:433
llvm::TargetOptions
Definition: TargetOptions.h:124
llvm::GlobalValue::LocalDynamicTLSModel
@ LocalDynamicTLSModel
Definition: GlobalValue.h:181
T
llvm::Function
Definition: Function.h:62
llvm::Target
Target - Wrapper for Target specific information.
Definition: TargetRegistry.h:137
llvm::TLSModel::GeneralDynamic
@ GeneralDynamic
Definition: CodeGen.h:43
llvm::GlobalValue::NotThreadLocal
@ NotThreadLocal
Definition: GlobalValue.h:179
llvm::TargetTransformInfo
This pass provides access to the codegen interfaces that are needed for IR-level transformations.
Definition: TargetTransformInfo.h:168
RESET_OPTION
#define RESET_OPTION(X, Y)
llvm::Triple
Triple - Helper class for working with autoconf configuration names.
Definition: Triple.h:45
getSelectedTLSModel
static TLSModel::Model getSelectedTLSModel(const GlobalValue *GV)
Get the IR-specified TLS model for Var.
Definition: TargetMachine.cpp:77
llvm::TargetMachine::getRelocationModel
Reloc::Model getRelocationModel() const
Returns the code generation relocation model.
Definition: TargetMachine.cpp:70
llvm::TargetMachine::RM
Reloc::Model RM
Definition: TargetMachine.h:102
llvm::Triple::hasDefaultEmulatedTLS
bool hasDefaultEmulatedTLS() const
Tests whether the target uses emulated TLS as default.
Definition: Triple.h:823
llvm::MipsISD::Ret
@ Ret
Definition: MipsISelLowering.h:116
llvm::Mangler
Definition: Mangler.h:27
llvm::MCObjectFileInfo::getContext
MCContext & getContext() const
Definition: MCObjectFileInfo.h:235
LegacyPassManager.h
llvm::TargetLoweringObjectFile::getTargetSymbol
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 ...
Definition: TargetLoweringObjectFile.h:264
llvm::GlobalValue::hasExternalWeakLinkage
bool hasExternalWeakLinkage() const
Definition: GlobalValue.h:452
F
#define F(x, y, z)
Definition: MD5.cpp:56
llvm::Reloc::Model
Model
Definition: CodeGen.h:22
llvm::TargetLoweringObjectFile
Definition: TargetLoweringObjectFile.h:43
llvm::MCContext::getOrCreateSymbol
MCSymbol * getOrCreateSymbol(const Twine &Name)
Lookup the symbol inside with the specified Name.
Definition: MCContext.cpp:191
GlobalValue.h
TargetMachine.h
llvm::GlobalValue::getThreadLocalMode
ThreadLocalMode getThreadLocalMode() const
Definition: GlobalValue.h:252
MCContext.h
MCSectionMachO.h
MCInstrInfo.h
llvm::TargetMachine::parseBinutilsVersion
static std::pair< int, int > parseBinutilsVersion(StringRef Version)
Definition: TargetMachine.cpp:224
llvm::GlobalValue::hasPrivateLinkage
bool hasPrivateLinkage() const
Definition: GlobalValue.h:450
false
Definition: StackSlotColoring.cpp:142
llvm::Mangler::getNameWithPrefix
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
llvm::X86AS::FS
@ FS
Definition: X86.h:188
Options
const char LLVMTargetMachineRef LLVMPassBuilderOptionsRef Options
Definition: PassBuilderBindings.cpp:48
llvm::IndexedInstrProf::Version
const uint64_t Version
Definition: InstrProf.h:991
llvm::TargetOptions::EmulatedTLS
unsigned EmulatedTLS
EmulatedTLS - This flag enables emulated TLS model, using emutls function in the runtime library.
Definition: TargetOptions.h:285
llvm::TargetMachine::getSymbol
MCSymbol * getSymbol(const GlobalValue *GV) const
Definition: TargetMachine.cpp:206
llvm::TargetMachine::resetTargetOptions
void resetTargetOptions(const Function &F) const
Reset the target options based on the function's attributes.
Definition: TargetMachine.cpp:56
llvm::SmallString< 128 >
llvm::TargetMachine::isPositionIndependent
bool isPositionIndependent() const
Definition: TargetMachine.cpp:44
llvm::CodeModel::Model
Model
Definition: CodeGen.h:28
llvm::GlobalValue
Definition: GlobalValue.h:44
llvm::TargetMachine::getTargetIRAnalysis
TargetIRAnalysis getTargetIRAnalysis()
Get a TargetIRAnalysis appropriate for the target.
Definition: TargetMachine.cpp:217
llvm::TLSModel::LocalDynamic
@ LocalDynamic
Definition: CodeGen.h:44
llvm::GlobalValue::getParent
Module * getParent()
Get the module that this global value is contained inside of...
Definition: GlobalValue.h:578
llvm::GlobalValue::GeneralDynamicTLSModel
@ GeneralDynamicTLSModel
Definition: GlobalValue.h:180
llvm::TargetMachine::OptLevel
CodeGenOpt::Level OptLevel
Definition: TargetMachine.h:104
llvm::TargetMachine::getTLSModel
TLSModel::Model getTLSModel(const GlobalValue *GV) const
Returns the TLS model which should be used for the given global variable.
Definition: TargetMachine.cpp:157
llvm::TargetMachine::Options
TargetOptions Options
Definition: TargetMachine.h:120
llvm::TargetMachine::TargetMachine
TargetMachine(const Target &T, StringRef DataLayoutString, const Triple &TargetTriple, StringRef CPU, StringRef FS, const TargetOptions &Options)
Definition: TargetMachine.cpp:34
assert
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
llvm::TargetMachine::getObjFileLowering
virtual TargetLoweringObjectFile * getObjFileLowering() const
Definition: TargetMachine.h:138
llvm::Module
A Module instance is used to store all the information related to an LLVM module.
Definition: Module.h:67
Mangler.h
llvm::TargetLoweringObjectFile::getMangler
Mangler & getMangler() const
Definition: TargetLoweringObjectFile.h:75
MCAsmInfo.h
llvm::Reloc::PIC_
@ PIC_
Definition: CodeGen.h:22
llvm::PIELevel::Default
@ Default
Definition: CodeGen.h:37
llvm::StringRef
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:58
llvm_unreachable
#define llvm_unreachable(msg)
Marks that the current location is not supposed to be reachable.
Definition: ErrorHandling.h:134
TargetLoweringObjectFile.h
llvm::Reloc::Static
@ Static
Definition: CodeGen.h:22
DL
MachineBasicBlock MachineBasicBlock::iterator DebugLoc DL
Definition: AArch64SLSHardening.cpp:76
llvm::PICLevel::Level
Level
Definition: CodeGen.h:33
llvm::TargetMachine::shouldAssumeDSOLocal
bool shouldAssumeDSOLocal(const Module &M, const GlobalValue *GV) const
Definition: TargetMachine.cpp:94
llvm::CodeGenOpt::Level
Level
Definition: CodeGen.h:52
llvm::GlobalValue::isStrongDefinitionForLinker
bool isStrongDefinitionForLinker() const
Returns true if this global's definition will be the one chosen by the linker.
Definition: GlobalValue.h:553
llvm::GlobalValue::LocalExecTLSModel
@ LocalExecTLSModel
Definition: GlobalValue.h:183
MRI
unsigned const MachineRegisterInfo * MRI
Definition: AArch64AdvSIMDScalarPass.cpp:105
llvm::GraphProgram::Name
Name
Definition: GraphWriter.h:52
std
Definition: BitVector.h:838
llvm::TargetMachine::getTargetTransformInfo
virtual TargetTransformInfo getTargetTransformInfo(const Function &F)
Return a TargetTransformInfo for a given function.
Definition: TargetMachine.cpp:189
llvm::TargetMachine::getNameWithPrefix
void getNameWithPrefix(SmallVectorImpl< char > &Name, const GlobalValue *GV, Mangler &Mang, bool MayAlwaysUsePrivate=false) const
Definition: TargetMachine.cpp:193
GlobalVariable.h
Function.h
llvm::TargetMachine::getCodeModel
CodeModel::Model getCodeModel() const
Returns the code model.
Definition: TargetMachine.cpp:74
llvm::TLSModel::Model
Model
Definition: CodeGen.h:42
llvm::Module::getPIELevel
PIELevel::Level getPIELevel() const
Returns the PIE level (small or large model)
Definition: Module.cpp:605
SectionKind.h
GlobalAlias.h
llvm::TLSModel::InitialExec
@ InitialExec
Definition: CodeGen.h:45
llvm::TargetMachine::CMModel
CodeModel::Model CMModel
Definition: TargetMachine.h:103
llvm::TargetMachine::~TargetMachine
virtual ~TargetMachine()
llvm::TargetMachine::getTargetTriple
const Triple & getTargetTriple() const
Definition: TargetMachine.h:128
TargetTransformInfo.h
llvm::GlobalValue::isDeclarationForLinker
bool isDeclarationForLinker() const
Definition: GlobalValue.h:540
llvm::GlobalValue::hasDLLImportStorageClass
bool hasDLLImportStorageClass() const
Definition: GlobalValue.h:259
llvm::SmallVectorImpl< char >
llvm::TargetMachine::setOptLevel
void setOptLevel(CodeGenOpt::Level Level)
Overrides the optimization level.
Definition: TargetMachine.cpp:187
llvm::GlobalValue::InitialExecTLSModel
@ InitialExecTLSModel
Definition: GlobalValue.h:182
llvm::GlobalValue::isDSOLocal
bool isDSOLocal() const
Definition: GlobalValue.h:282
llvm::TargetOptions::ExplicitEmulatedTLS
unsigned ExplicitEmulatedTLS
Whether -emulated-tls or -no-emulated-tls is set.
Definition: TargetOptions.h:288
SpecialSubKind::string
@ string
llvm::TLSModel::LocalExec
@ LocalExec
Definition: CodeGen.h:46