1 //===-- TargetMachine.cpp - General Target Information ---------------------==//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file describes the general parts of a Target machine.
12 //===----------------------------------------------------------------------===//
14 #include "llvm/Target/TargetMachine.h"
15 #include "llvm/Analysis/TargetTransformInfo.h"
16 #include "llvm/CodeGen/MachineFunction.h"
17 #include "llvm/IR/Function.h"
18 #include "llvm/IR/GlobalAlias.h"
19 #include "llvm/IR/GlobalValue.h"
20 #include "llvm/IR/GlobalVariable.h"
21 #include "llvm/IR/Mangler.h"
22 #include "llvm/MC/MCAsmInfo.h"
23 #include "llvm/MC/MCCodeGenInfo.h"
24 #include "llvm/MC/MCContext.h"
25 #include "llvm/MC/MCInstrInfo.h"
26 #include "llvm/MC/MCSectionMachO.h"
27 #include "llvm/MC/MCTargetOptions.h"
28 #include "llvm/MC/SectionKind.h"
29 #include "llvm/IR/LegacyPassManager.h"
30 #include "llvm/Support/CommandLine.h"
31 #include "llvm/Target/TargetLowering.h"
32 #include "llvm/Target/TargetLoweringObjectFile.h"
33 #include "llvm/Target/TargetSubtargetInfo.h"
36 //---------------------------------------------------------------------------
37 // TargetMachine Class
40 TargetMachine::TargetMachine(const Target &T, StringRef DataLayoutString,
41 StringRef TT, StringRef CPU, StringRef FS,
42 const TargetOptions &Options)
43 : TheTarget(T), DL(DataLayoutString), TargetTriple(TT), TargetCPU(CPU),
44 TargetFS(FS), CodeGenInfo(nullptr), AsmInfo(nullptr), MRI(nullptr),
45 MII(nullptr), STI(nullptr), RequireStructuredCFG(false),
48 TargetMachine::~TargetMachine() {
56 /// \brief Reset the target options based on the function's attributes.
57 // FIXME: This function needs to go away for a number of reasons:
58 // a) global state on the TargetMachine is terrible in general,
59 // b) there's no default state here to keep,
60 // c) these target options should be passed only on the function
61 // and not on the TargetMachine (via TargetOptions) at all.
62 void TargetMachine::resetTargetOptions(const Function &F) const {
63 #define RESET_OPTION(X, Y) \
65 if (F.hasFnAttribute(Y)) \
66 Options.X = (F.getFnAttribute(Y).getValueAsString() == "true"); \
69 RESET_OPTION(NoFramePointerElim, "no-frame-pointer-elim");
70 RESET_OPTION(LessPreciseFPMADOption, "less-precise-fpmad");
71 RESET_OPTION(UnsafeFPMath, "unsafe-fp-math");
72 RESET_OPTION(NoInfsFPMath, "no-infs-fp-math");
73 RESET_OPTION(NoNaNsFPMath, "no-nans-fp-math");
74 RESET_OPTION(DisableTailCalls, "disable-tail-calls");
77 /// getRelocationModel - Returns the code generation relocation model. The
78 /// choices are static, PIC, and dynamic-no-pic, and target default.
79 Reloc::Model TargetMachine::getRelocationModel() const {
81 return Reloc::Default;
82 return CodeGenInfo->getRelocationModel();
85 /// getCodeModel - Returns the code model. The choices are small, kernel,
86 /// medium, large, and target default.
87 CodeModel::Model TargetMachine::getCodeModel() const {
89 return CodeModel::Default;
90 return CodeGenInfo->getCodeModel();
93 /// Get the IR-specified TLS model for Var.
94 static TLSModel::Model getSelectedTLSModel(const GlobalValue *GV) {
95 switch (GV->getThreadLocalMode()) {
96 case GlobalVariable::NotThreadLocal:
97 llvm_unreachable("getSelectedTLSModel for non-TLS variable");
99 case GlobalVariable::GeneralDynamicTLSModel:
100 return TLSModel::GeneralDynamic;
101 case GlobalVariable::LocalDynamicTLSModel:
102 return TLSModel::LocalDynamic;
103 case GlobalVariable::InitialExecTLSModel:
104 return TLSModel::InitialExec;
105 case GlobalVariable::LocalExecTLSModel:
106 return TLSModel::LocalExec;
108 llvm_unreachable("invalid TLS model");
111 TLSModel::Model TargetMachine::getTLSModel(const GlobalValue *GV) const {
112 bool isLocal = GV->hasLocalLinkage();
113 bool isDeclaration = GV->isDeclaration();
114 bool isPIC = getRelocationModel() == Reloc::PIC_;
115 bool isPIE = Options.PositionIndependentExecutable;
116 // FIXME: what should we do for protected and internal visibility?
117 // For variables, is internal different from hidden?
118 bool isHidden = GV->hasHiddenVisibility();
120 TLSModel::Model Model;
121 if (isPIC && !isPIE) {
122 if (isLocal || isHidden)
123 Model = TLSModel::LocalDynamic;
125 Model = TLSModel::GeneralDynamic;
127 if (!isDeclaration || isHidden)
128 Model = TLSModel::LocalExec;
130 Model = TLSModel::InitialExec;
133 // If the user specified a more specific model, use that.
134 TLSModel::Model SelectedModel = getSelectedTLSModel(GV);
135 if (SelectedModel > Model)
136 return SelectedModel;
141 /// getOptLevel - Returns the optimization level: None, Less,
142 /// Default, or Aggressive.
143 CodeGenOpt::Level TargetMachine::getOptLevel() const {
145 return CodeGenOpt::Default;
146 return CodeGenInfo->getOptLevel();
149 void TargetMachine::setOptLevel(CodeGenOpt::Level Level) const {
151 CodeGenInfo->setOptLevel(Level);
154 TargetIRAnalysis TargetMachine::getTargetIRAnalysis() {
155 return TargetIRAnalysis(
156 [this](Function &) { return TargetTransformInfo(getDataLayout()); });
159 static bool canUsePrivateLabel(const MCAsmInfo &AsmInfo,
160 const MCSection &Section) {
161 if (!AsmInfo.isSectionAtomizableBySymbols(Section))
164 // If it is not dead stripped, it is safe to use private labels.
165 const MCSectionMachO &SMO = cast<MCSectionMachO>(Section);
166 if (SMO.hasAttribute(MachO::S_ATTR_NO_DEAD_STRIP))
172 void TargetMachine::getNameWithPrefix(SmallVectorImpl<char> &Name,
173 const GlobalValue *GV, Mangler &Mang,
174 bool MayAlwaysUsePrivate) const {
175 if (MayAlwaysUsePrivate || !GV->hasPrivateLinkage()) {
176 // Simple case: If GV is not private, it is not important to find out if
177 // private labels are legal in this case or not.
178 Mang.getNameWithPrefix(Name, GV, false);
181 SectionKind GVKind = TargetLoweringObjectFile::getKindForGlobal(GV, *this);
182 const TargetLoweringObjectFile *TLOF = getObjFileLowering();
183 const MCSection *TheSection = TLOF->SectionForGlobal(GV, GVKind, Mang, *this);
184 bool CannotUsePrivateLabel = !canUsePrivateLabel(*AsmInfo, *TheSection);
185 TLOF->getNameWithPrefix(Name, GV, CannotUsePrivateLabel, Mang, *this);
188 MCSymbol *TargetMachine::getSymbol(const GlobalValue *GV, Mangler &Mang) const {
189 SmallString<60> NameStr;
190 getNameWithPrefix(NameStr, GV, Mang);
191 const TargetLoweringObjectFile *TLOF = getObjFileLowering();
192 return TLOF->getContext().GetOrCreateSymbol(NameStr);