LLVM  13.0.0git
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 
34 TargetMachine::TargetMachine(const Target &T, StringRef DataLayoutString,
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  // In the case of ExternalSymbolSDNode, GV is null and we should just return
105  // false. However, COFF currently relies on this to be true
106  //
107  // As a result we still have some logic in here to improve the quality of the
108  // generated code.
109  // FIXME: Add a module level metadata for whether intrinsics should be assumed
110  // local.
111  if (!GV)
112  return TT.isOSBinFormatCOFF();
113 
114  // If the IR producer requested that this GV be treated as dso local, obey.
115  if (GV->isDSOLocal())
116  return true;
117 
118  // DLLImport explicitly marks the GV as external.
119  if (GV->hasDLLImportStorageClass())
120  return false;
121 
122  // On MinGW, variables that haven't been declared with DLLImport may still
123  // end up automatically imported by the linker. To make this feasible,
124  // don't assume the variables to be DSO local unless we actually know
125  // that for sure. This only has to be done for variables; for functions
126  // the linker can insert thunks for calling functions from another DLL.
127  if (TT.isWindowsGNUEnvironment() && TT.isOSBinFormatCOFF() &&
128  GV->isDeclarationForLinker() && isa<GlobalVariable>(GV))
129  return false;
130 
131  // On COFF, don't mark 'extern_weak' symbols as DSO local. If these symbols
132  // remain unresolved in the link, they can be resolved to zero, which is
133  // outside the current DSO.
134  if (TT.isOSBinFormatCOFF() && GV->hasExternalWeakLinkage())
135  return false;
136 
137  // Every other GV is local on COFF.
138  // Make an exception for windows OS in the triple: Some firmware builds use
139  // *-win32-macho triples. This (accidentally?) produced windows relocations
140  // without GOT tables in older clang versions; Keep this behaviour.
141  // Some JIT users use *-win32-elf triples; these shouldn't use GOT tables
142  // either.
143  if (TT.isOSBinFormatCOFF() || TT.isOSWindows())
144  return true;
145 
146  if (TT.isOSBinFormatMachO()) {
147  if (RM == Reloc::Static)
148  return true;
149  return GV->isStrongDefinitionForLinker();
150  }
151 
152  // Due to the AIX linkage model, any global with default visibility is
153  // considered non-local.
154  if (TT.isOSBinFormatXCOFF())
155  return false;
156 
157  assert(TT.isOSBinFormatELF() || TT.isOSBinFormatWasm());
159  return false;
160 }
161 
163  // Returns Options.EmulatedTLS if the -emulated-tls or -no-emulated-tls
164  // was specified explicitly; otherwise uses target triple to decide default.
166  return Options.EmulatedTLS;
168 }
169 
171  bool IsPIE = GV->getParent()->getPIELevel() != PIELevel::Default;
173  bool IsSharedLibrary = RM == Reloc::PIC_ && !IsPIE;
174  bool IsLocal = shouldAssumeDSOLocal(*GV->getParent(), GV);
175 
177  if (IsSharedLibrary) {
178  if (IsLocal)
180  else
182  } else {
183  if (IsLocal)
185  else
187  }
188 
189  // If the user specified a more specific model, use that.
190  TLSModel::Model SelectedModel = getSelectedTLSModel(GV);
191  if (SelectedModel > Model)
192  return SelectedModel;
193 
194  return Model;
195 }
196 
197 /// Returns the optimization level: None, Less, Default, or Aggressive.
199 
201 
203  return TargetTransformInfo(F.getParent()->getDataLayout());
204 }
205 
207  const GlobalValue *GV, Mangler &Mang,
208  bool MayAlwaysUsePrivate) const {
209  if (MayAlwaysUsePrivate || !GV->hasPrivateLinkage()) {
210  // Simple case: If GV is not private, it is not important to find out if
211  // private labels are legal in this case or not.
212  Mang.getNameWithPrefix(Name, GV, false);
213  return;
214  }
216  TLOF->getNameWithPrefix(Name, GV, *this);
217 }
218 
221  // XCOFF symbols could have special naming convention.
222  if (MCSymbol *TargetSymbol = TLOF->getTargetSymbol(GV, *this))
223  return TargetSymbol;
224 
225  SmallString<128> NameStr;
226  getNameWithPrefix(NameStr, GV, TLOF->getMangler());
227  return TLOF->getContext().getOrCreateSymbol(NameStr);
228 }
229 
231  // Since Analysis can't depend on Target, use a std::function to invert the
232  // dependency.
233  return TargetIRAnalysis(
234  [this](const Function &F) { return this->getTargetTransformInfo(F); });
235 }
236 
238  if (Version == "none")
239  return {INT_MAX, INT_MAX}; // Make binutilsIsAtLeast() return true.
240  std::pair<int, int> Ret;
241  if (!Version.consumeInteger(10, Ret.first) && Version.consume_front("."))
242  Version.consumeInteger(10, Ret.second);
243  return Ret;
244 }
llvm::TargetMachine::getOptLevel
CodeGenOpt::Level getOptLevel() const
Returns the optimization level: None, Less, Default, or Aggressive.
Definition: TargetMachine.cpp:198
llvm::TargetIRAnalysis
Analysis pass providing the TargetTransformInfo.
Definition: TargetTransformInfo.h:2319
llvm
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:162
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:119
llvm::GlobalValue::LocalDynamicTLSModel
@ LocalDynamicTLSModel
Definition: GlobalValue.h:181
llvm::Function
Definition: Function.h:61
llvm::Target
Target - Wrapper for Target specific information.
Definition: TargetRegistry.h:124
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:167
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:100
T
#define T
Definition: Mips16ISelLowering.cpp:341
llvm::Triple::hasDefaultEmulatedTLS
bool hasDefaultEmulatedTLS() const
Tests whether the target uses emulated TLS as default.
Definition: Triple.h:814
llvm::MipsISD::Ret
@ Ret
Definition: MipsISelLowering.h:116
llvm::Mangler
Definition: Mangler.h:27
llvm::X86AS::FS
@ FS
Definition: X86.h:183
llvm::MCObjectFileInfo::getContext
MCContext & getContext() const
Definition: MCObjectFileInfo.h:232
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:446
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:187
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:237
llvm::GlobalValue::hasPrivateLinkage
bool hasPrivateLinkage() const
Definition: GlobalValue.h:444
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:114
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:271
llvm::TargetMachine::getSymbol
MCSymbol * getSymbol(const GlobalValue *GV) const
Definition: TargetMachine.cpp:219
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:230
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:572
llvm::GlobalValue::GeneralDynamicTLSModel
@ GeneralDynamicTLSModel
Definition: GlobalValue.h:180
llvm::TargetMachine::OptLevel
CodeGenOpt::Level OptLevel
Definition: TargetMachine.h:102
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:170
llvm::TargetMachine::Options
TargetOptions Options
Definition: TargetMachine.h:115
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:133
llvm::Module
A Module instance is used to store all the information related to an LLVM module.
Definition: Module.h:67
llvm::Reloc::DynamicNoPIC
@ DynamicNoPIC
Definition: CodeGen.h:22
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:57
llvm_unreachable
#define llvm_unreachable(msg)
Marks that the current location is not supposed to be reachable.
Definition: ErrorHandling.h:136
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:547
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:202
llvm::TargetMachine::getNameWithPrefix
void getNameWithPrefix(SmallVectorImpl< char > &Name, const GlobalValue *GV, Mangler &Mang, bool MayAlwaysUsePrivate=false) const
Definition: TargetMachine.cpp:206
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:601
SectionKind.h
GlobalAlias.h
llvm::TLSModel::InitialExec
@ InitialExec
Definition: CodeGen.h:45
llvm::TargetMachine::CMModel
CodeModel::Model CMModel
Definition: TargetMachine.h:101
llvm::TargetMachine::~TargetMachine
virtual ~TargetMachine()
llvm::TargetMachine::getTargetTriple
const Triple & getTargetTriple() const
Definition: TargetMachine.h:123
TargetTransformInfo.h
llvm::GlobalValue::isDeclarationForLinker
bool isDeclarationForLinker() const
Definition: GlobalValue.h:534
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:200
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:274
SpecialSubKind::string
@ string
llvm::TLSModel::LocalExec
@ LocalExec
Definition: CodeGen.h:46