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(LessPreciseFPMADOption, "less-precise-fpmad");
70 RESET_OPTION(UnsafeFPMath, "unsafe-fp-math");
71 RESET_OPTION(NoInfsFPMath, "no-infs-fp-math");
72 RESET_OPTION(NoNaNsFPMath, "no-nans-fp-math");
73 RESET_OPTION(DisableTailCalls, "disable-tail-calls");
76 /// getRelocationModel - Returns the code generation relocation model. The
77 /// choices are static, PIC, and dynamic-no-pic, and target default.
78 Reloc::Model TargetMachine::getRelocationModel() const {
80 return Reloc::Default;
81 return CodeGenInfo->getRelocationModel();
84 /// getCodeModel - Returns the code model. The choices are small, kernel,
85 /// medium, large, and target default.
86 CodeModel::Model TargetMachine::getCodeModel() const {
88 return CodeModel::Default;
89 return CodeGenInfo->getCodeModel();
92 /// Get the IR-specified TLS model for Var.
93 static TLSModel::Model getSelectedTLSModel(const GlobalValue *GV) {
94 switch (GV->getThreadLocalMode()) {
95 case GlobalVariable::NotThreadLocal:
96 llvm_unreachable("getSelectedTLSModel for non-TLS variable");
98 case GlobalVariable::GeneralDynamicTLSModel:
99 return TLSModel::GeneralDynamic;
100 case GlobalVariable::LocalDynamicTLSModel:
101 return TLSModel::LocalDynamic;
102 case GlobalVariable::InitialExecTLSModel:
103 return TLSModel::InitialExec;
104 case GlobalVariable::LocalExecTLSModel:
105 return TLSModel::LocalExec;
107 llvm_unreachable("invalid TLS model");
110 TLSModel::Model TargetMachine::getTLSModel(const GlobalValue *GV) const {
111 bool isLocal = GV->hasLocalLinkage();
112 bool isDeclaration = GV->isDeclaration();
113 bool isPIC = getRelocationModel() == Reloc::PIC_;
114 bool isPIE = Options.PositionIndependentExecutable;
115 // FIXME: what should we do for protected and internal visibility?
116 // For variables, is internal different from hidden?
117 bool isHidden = GV->hasHiddenVisibility();
119 TLSModel::Model Model;
120 if (isPIC && !isPIE) {
121 if (isLocal || isHidden)
122 Model = TLSModel::LocalDynamic;
124 Model = TLSModel::GeneralDynamic;
126 if (!isDeclaration || isHidden)
127 Model = TLSModel::LocalExec;
129 Model = TLSModel::InitialExec;
132 // If the user specified a more specific model, use that.
133 TLSModel::Model SelectedModel = getSelectedTLSModel(GV);
134 if (SelectedModel > Model)
135 return SelectedModel;
140 /// getOptLevel - Returns the optimization level: None, Less,
141 /// Default, or Aggressive.
142 CodeGenOpt::Level TargetMachine::getOptLevel() const {
144 return CodeGenOpt::Default;
145 return CodeGenInfo->getOptLevel();
148 void TargetMachine::setOptLevel(CodeGenOpt::Level Level) const {
150 CodeGenInfo->setOptLevel(Level);
153 TargetIRAnalysis TargetMachine::getTargetIRAnalysis() {
154 return TargetIRAnalysis(
155 [this](Function &) { return TargetTransformInfo(getDataLayout()); });
158 static bool canUsePrivateLabel(const MCAsmInfo &AsmInfo,
159 const MCSection &Section) {
160 if (!AsmInfo.isSectionAtomizableBySymbols(Section))
163 // If it is not dead stripped, it is safe to use private labels.
164 const MCSectionMachO &SMO = cast<MCSectionMachO>(Section);
165 if (SMO.hasAttribute(MachO::S_ATTR_NO_DEAD_STRIP))
171 void TargetMachine::getNameWithPrefix(SmallVectorImpl<char> &Name,
172 const GlobalValue *GV, Mangler &Mang,
173 bool MayAlwaysUsePrivate) const {
174 if (MayAlwaysUsePrivate || !GV->hasPrivateLinkage()) {
175 // Simple case: If GV is not private, it is not important to find out if
176 // private labels are legal in this case or not.
177 Mang.getNameWithPrefix(Name, GV, false);
180 SectionKind GVKind = TargetLoweringObjectFile::getKindForGlobal(GV, *this);
181 const TargetLoweringObjectFile *TLOF = getObjFileLowering();
182 const MCSection *TheSection = TLOF->SectionForGlobal(GV, GVKind, Mang, *this);
183 bool CannotUsePrivateLabel = !canUsePrivateLabel(*AsmInfo, *TheSection);
184 TLOF->getNameWithPrefix(Name, GV, CannotUsePrivateLabel, Mang, *this);
187 MCSymbol *TargetMachine::getSymbol(const GlobalValue *GV, Mangler &Mang) const {
188 SmallString<128> NameStr;
189 getNameWithPrefix(NameStr, GV, Mang);
190 const TargetLoweringObjectFile *TLOF = getObjFileLowering();
191 return TLOF->getContext().getOrCreateSymbol(NameStr);