1 //===-- TargetMachine.cpp - General Target Information ---------------------==//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file describes the general parts of a Target machine.
11 //
12 //===----------------------------------------------------------------------===//
13
14 #include "llvm/Target/TargetMachine.h"
15 #include "llvm/CodeGen/MachineFunction.h"
16 #include "llvm/IR/Function.h"
17 #include "llvm/IR/GlobalAlias.h"
18 #include "llvm/IR/GlobalValue.h"
19 #include "llvm/IR/GlobalVariable.h"
20 #include "llvm/IR/Mangler.h"
21 #include "llvm/MC/MCAsmInfo.h"
22 #include "llvm/MC/MCCodeGenInfo.h"
23 #include "llvm/MC/MCContext.h"
24 #include "llvm/MC/MCTargetOptions.h"
25 #include "llvm/MC/SectionKind.h"
26 #include "llvm/Support/CommandLine.h"
27 #include "llvm/Target/TargetLowering.h"
28 #include "llvm/Target/TargetLoweringObjectFile.h"
29 using namespace llvm;
30
31 //---------------------------------------------------------------------------
32 // TargetMachine Class
33 //
34
TargetMachine(const Target & T,StringRef TT,StringRef CPU,StringRef FS,const TargetOptions & Options)35 TargetMachine::TargetMachine(const Target &T,
36 StringRef TT, StringRef CPU, StringRef FS,
37 const TargetOptions &Options)
38 : TheTarget(T), TargetTriple(TT), TargetCPU(CPU), TargetFS(FS),
39 CodeGenInfo(nullptr), AsmInfo(nullptr),
40 RequireStructuredCFG(false),
41 Options(Options) {
42 }
43
~TargetMachine()44 TargetMachine::~TargetMachine() {
45 delete CodeGenInfo;
46 delete AsmInfo;
47 }
48
49 /// \brief Reset the target options based on the function's attributes.
resetTargetOptions(const MachineFunction * MF) const50 void TargetMachine::resetTargetOptions(const MachineFunction *MF) const {
51 const Function *F = MF->getFunction();
52 TargetOptions &TO = MF->getTarget().Options;
53
54 #define RESET_OPTION(X, Y) \
55 do { \
56 if (F->hasFnAttribute(Y)) \
57 TO.X = \
58 (F->getAttributes(). \
59 getAttribute(AttributeSet::FunctionIndex, \
60 Y).getValueAsString() == "true"); \
61 } while (0)
62
63 RESET_OPTION(NoFramePointerElim, "no-frame-pointer-elim");
64 RESET_OPTION(LessPreciseFPMADOption, "less-precise-fpmad");
65 RESET_OPTION(UnsafeFPMath, "unsafe-fp-math");
66 RESET_OPTION(NoInfsFPMath, "no-infs-fp-math");
67 RESET_OPTION(NoNaNsFPMath, "no-nans-fp-math");
68 RESET_OPTION(UseSoftFloat, "use-soft-float");
69 RESET_OPTION(DisableTailCalls, "disable-tail-calls");
70
71 TO.MCOptions.SanitizeAddress = F->hasFnAttribute(Attribute::SanitizeAddress);
72 }
73
74 /// getRelocationModel - Returns the code generation relocation model. The
75 /// choices are static, PIC, and dynamic-no-pic, and target default.
getRelocationModel() const76 Reloc::Model TargetMachine::getRelocationModel() const {
77 if (!CodeGenInfo)
78 return Reloc::Default;
79 return CodeGenInfo->getRelocationModel();
80 }
81
82 /// getCodeModel - Returns the code model. The choices are small, kernel,
83 /// medium, large, and target default.
getCodeModel() const84 CodeModel::Model TargetMachine::getCodeModel() const {
85 if (!CodeGenInfo)
86 return CodeModel::Default;
87 return CodeGenInfo->getCodeModel();
88 }
89
90 /// Get the IR-specified TLS model for Var.
getSelectedTLSModel(const GlobalValue * GV)91 static TLSModel::Model getSelectedTLSModel(const GlobalValue *GV) {
92 switch (GV->getThreadLocalMode()) {
93 case GlobalVariable::NotThreadLocal:
94 llvm_unreachable("getSelectedTLSModel for non-TLS variable");
95 break;
96 case GlobalVariable::GeneralDynamicTLSModel:
97 return TLSModel::GeneralDynamic;
98 case GlobalVariable::LocalDynamicTLSModel:
99 return TLSModel::LocalDynamic;
100 case GlobalVariable::InitialExecTLSModel:
101 return TLSModel::InitialExec;
102 case GlobalVariable::LocalExecTLSModel:
103 return TLSModel::LocalExec;
104 }
105 llvm_unreachable("invalid TLS model");
106 }
107
getTLSModel(const GlobalValue * GV) const108 TLSModel::Model TargetMachine::getTLSModel(const GlobalValue *GV) const {
109 bool isLocal = GV->hasLocalLinkage();
110 bool isDeclaration = GV->isDeclaration();
111 bool isPIC = getRelocationModel() == Reloc::PIC_;
112 bool isPIE = Options.PositionIndependentExecutable;
113 // FIXME: what should we do for protected and internal visibility?
114 // For variables, is internal different from hidden?
115 bool isHidden = GV->hasHiddenVisibility();
116
117 TLSModel::Model Model;
118 if (isPIC && !isPIE) {
119 if (isLocal || isHidden)
120 Model = TLSModel::LocalDynamic;
121 else
122 Model = TLSModel::GeneralDynamic;
123 } else {
124 if (!isDeclaration || isHidden)
125 Model = TLSModel::LocalExec;
126 else
127 Model = TLSModel::InitialExec;
128 }
129
130 // If the user specified a more specific model, use that.
131 TLSModel::Model SelectedModel = getSelectedTLSModel(GV);
132 if (SelectedModel > Model)
133 return SelectedModel;
134
135 return Model;
136 }
137
138 /// getOptLevel - Returns the optimization level: None, Less,
139 /// Default, or Aggressive.
getOptLevel() const140 CodeGenOpt::Level TargetMachine::getOptLevel() const {
141 if (!CodeGenInfo)
142 return CodeGenOpt::Default;
143 return CodeGenInfo->getOptLevel();
144 }
145
setOptLevel(CodeGenOpt::Level Level) const146 void TargetMachine::setOptLevel(CodeGenOpt::Level Level) const {
147 if (CodeGenInfo)
148 CodeGenInfo->setOptLevel(Level);
149 }
150
getAsmVerbosityDefault() const151 bool TargetMachine::getAsmVerbosityDefault() const {
152 return Options.MCOptions.AsmVerbose;
153 }
154
setAsmVerbosityDefault(bool V)155 void TargetMachine::setAsmVerbosityDefault(bool V) {
156 Options.MCOptions.AsmVerbose = V;
157 }
158
getFunctionSections() const159 bool TargetMachine::getFunctionSections() const {
160 return Options.FunctionSections;
161 }
162
getDataSections() const163 bool TargetMachine::getDataSections() const {
164 return Options.DataSections;
165 }
166
setFunctionSections(bool V)167 void TargetMachine::setFunctionSections(bool V) {
168 Options.FunctionSections = V;
169 }
170
setDataSections(bool V)171 void TargetMachine::setDataSections(bool V) {
172 Options.DataSections = V;
173 }
174
getNameWithPrefix(SmallVectorImpl<char> & Name,const GlobalValue * GV,Mangler & Mang,bool MayAlwaysUsePrivate) const175 void TargetMachine::getNameWithPrefix(SmallVectorImpl<char> &Name,
176 const GlobalValue *GV, Mangler &Mang,
177 bool MayAlwaysUsePrivate) const {
178 if (MayAlwaysUsePrivate || !GV->hasPrivateLinkage()) {
179 // Simple case: If GV is not private, it is not important to find out if
180 // private labels are legal in this case or not.
181 Mang.getNameWithPrefix(Name, GV, false);
182 return;
183 }
184 SectionKind GVKind = TargetLoweringObjectFile::getKindForGlobal(GV, *this);
185 const TargetLoweringObjectFile &TLOF =
186 getTargetLowering()->getObjFileLowering();
187 const MCSection *TheSection = TLOF.SectionForGlobal(GV, GVKind, Mang, *this);
188 bool CannotUsePrivateLabel = TLOF.isSectionAtomizableBySymbols(*TheSection);
189 Mang.getNameWithPrefix(Name, GV, CannotUsePrivateLabel);
190 }
191
getSymbol(const GlobalValue * GV,Mangler & Mang) const192 MCSymbol *TargetMachine::getSymbol(const GlobalValue *GV, Mangler &Mang) const {
193 SmallString<60> NameStr;
194 getNameWithPrefix(NameStr, GV, Mang);
195 const TargetLoweringObjectFile &TLOF =
196 getTargetLowering()->getObjFileLowering();
197 return TLOF.getContext().GetOrCreateSymbol(NameStr.str());
198 }
199