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/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"
34 using namespace llvm;
35
36 //---------------------------------------------------------------------------
37 // TargetMachine Class
38 //
39
TargetMachine(const Target & T,StringRef DataLayoutString,const Triple & TT,StringRef CPU,StringRef FS,const TargetOptions & Options)40 TargetMachine::TargetMachine(const Target &T, StringRef DataLayoutString,
41 const Triple &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),
46 Options(Options) {}
47
~TargetMachine()48 TargetMachine::~TargetMachine() {
49 delete CodeGenInfo;
50 delete AsmInfo;
51 delete MRI;
52 delete MII;
53 delete STI;
54 }
55
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.
resetTargetOptions(const Function & F) const62 void TargetMachine::resetTargetOptions(const Function &F) const {
63 #define RESET_OPTION(X, Y) \
64 do { \
65 if (F.hasFnAttribute(Y)) \
66 Options.X = (F.getFnAttribute(Y).getValueAsString() == "true"); \
67 } while (0)
68
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 }
74
75 /// getRelocationModel - Returns the code generation relocation model. The
76 /// choices are static, PIC, and dynamic-no-pic, and target default.
getRelocationModel() const77 Reloc::Model TargetMachine::getRelocationModel() const {
78 if (!CodeGenInfo)
79 return Reloc::Default;
80 return CodeGenInfo->getRelocationModel();
81 }
82
83 /// getCodeModel - Returns the code model. The choices are small, kernel,
84 /// medium, large, and target default.
getCodeModel() const85 CodeModel::Model TargetMachine::getCodeModel() const {
86 if (!CodeGenInfo)
87 return CodeModel::Default;
88 return CodeGenInfo->getCodeModel();
89 }
90
91 /// Get the IR-specified TLS model for Var.
getSelectedTLSModel(const GlobalValue * GV)92 static TLSModel::Model getSelectedTLSModel(const GlobalValue *GV) {
93 switch (GV->getThreadLocalMode()) {
94 case GlobalVariable::NotThreadLocal:
95 llvm_unreachable("getSelectedTLSModel for non-TLS variable");
96 break;
97 case GlobalVariable::GeneralDynamicTLSModel:
98 return TLSModel::GeneralDynamic;
99 case GlobalVariable::LocalDynamicTLSModel:
100 return TLSModel::LocalDynamic;
101 case GlobalVariable::InitialExecTLSModel:
102 return TLSModel::InitialExec;
103 case GlobalVariable::LocalExecTLSModel:
104 return TLSModel::LocalExec;
105 }
106 llvm_unreachable("invalid TLS model");
107 }
108
getTLSModel(const GlobalValue * GV) const109 TLSModel::Model TargetMachine::getTLSModel(const GlobalValue *GV) const {
110 bool isLocal = GV->hasLocalLinkage();
111 bool isDeclaration = GV->isDeclaration();
112 bool isPIC = getRelocationModel() == Reloc::PIC_;
113 bool isPIE = Options.PositionIndependentExecutable;
114 // FIXME: what should we do for protected and internal visibility?
115 // For variables, is internal different from hidden?
116 bool isHidden = GV->hasHiddenVisibility();
117
118 TLSModel::Model Model;
119 if (isPIC && !isPIE) {
120 if (isLocal || isHidden)
121 Model = TLSModel::LocalDynamic;
122 else
123 Model = TLSModel::GeneralDynamic;
124 } else {
125 if (!isDeclaration || isHidden)
126 Model = TLSModel::LocalExec;
127 else
128 Model = TLSModel::InitialExec;
129 }
130
131 // If the user specified a more specific model, use that.
132 TLSModel::Model SelectedModel = getSelectedTLSModel(GV);
133 if (SelectedModel > Model)
134 return SelectedModel;
135
136 return Model;
137 }
138
139 /// getOptLevel - Returns the optimization level: None, Less,
140 /// Default, or Aggressive.
getOptLevel() const141 CodeGenOpt::Level TargetMachine::getOptLevel() const {
142 if (!CodeGenInfo)
143 return CodeGenOpt::Default;
144 return CodeGenInfo->getOptLevel();
145 }
146
setOptLevel(CodeGenOpt::Level Level) const147 void TargetMachine::setOptLevel(CodeGenOpt::Level Level) const {
148 if (CodeGenInfo)
149 CodeGenInfo->setOptLevel(Level);
150 }
151
getTargetIRAnalysis()152 TargetIRAnalysis TargetMachine::getTargetIRAnalysis() {
153 return TargetIRAnalysis([this](const Function &F) {
154 return TargetTransformInfo(F.getParent()->getDataLayout());
155 });
156 }
157
getNameWithPrefix(SmallVectorImpl<char> & Name,const GlobalValue * GV,Mangler & Mang,bool MayAlwaysUsePrivate) const158 void TargetMachine::getNameWithPrefix(SmallVectorImpl<char> &Name,
159 const GlobalValue *GV, Mangler &Mang,
160 bool MayAlwaysUsePrivate) const {
161 if (MayAlwaysUsePrivate || !GV->hasPrivateLinkage()) {
162 // Simple case: If GV is not private, it is not important to find out if
163 // private labels are legal in this case or not.
164 Mang.getNameWithPrefix(Name, GV, false);
165 return;
166 }
167 const TargetLoweringObjectFile *TLOF = getObjFileLowering();
168 TLOF->getNameWithPrefix(Name, GV, Mang, *this);
169 }
170
getSymbol(const GlobalValue * GV,Mangler & Mang) const171 MCSymbol *TargetMachine::getSymbol(const GlobalValue *GV, Mangler &Mang) const {
172 SmallString<128> NameStr;
173 getNameWithPrefix(NameStr, GV, Mang);
174 const TargetLoweringObjectFile *TLOF = getObjFileLowering();
175 return TLOF->getContext().getOrCreateSymbol(NameStr);
176 }
177