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/MC/MCAsmInfo.h"
21 #include "llvm/MC/MCCodeGenInfo.h"
22 #include "llvm/Support/CommandLine.h"
23 using namespace llvm;
24
25 //---------------------------------------------------------------------------
26 // Command-line options that tend to be useful on more than one back-end.
27 //
28
29 namespace llvm {
30 bool HasDivModLibcall;
31 bool AsmVerbosityDefault(false);
32 }
33
34 static cl::opt<bool>
35 DataSections("fdata-sections",
36 cl::desc("Emit data into separate sections"),
37 cl::init(false));
38 static cl::opt<bool>
39 FunctionSections("ffunction-sections",
40 cl::desc("Emit functions into separate sections"),
41 cl::init(false));
42
43 //---------------------------------------------------------------------------
44 // TargetMachine Class
45 //
46
TargetMachine(const Target & T,StringRef TT,StringRef CPU,StringRef FS,const TargetOptions & Options)47 TargetMachine::TargetMachine(const Target &T,
48 StringRef TT, StringRef CPU, StringRef FS,
49 const TargetOptions &Options)
50 : TheTarget(T), TargetTriple(TT), TargetCPU(CPU), TargetFS(FS),
51 CodeGenInfo(0), AsmInfo(0),
52 MCRelaxAll(false),
53 MCNoExecStack(false),
54 MCSaveTempLabels(false),
55 MCUseLoc(true),
56 MCUseCFI(true),
57 MCUseDwarfDirectory(false),
58 Options(Options) {
59 }
60
~TargetMachine()61 TargetMachine::~TargetMachine() {
62 delete CodeGenInfo;
63 delete AsmInfo;
64 }
65
66 /// \brief Reset the target options based on the function's attributes.
resetTargetOptions(const MachineFunction * MF) const67 void TargetMachine::resetTargetOptions(const MachineFunction *MF) const {
68 const Function *F = MF->getFunction();
69 TargetOptions &TO = MF->getTarget().Options;
70
71 #define RESET_OPTION(X, Y) \
72 do { \
73 if (F->hasFnAttribute(Y)) \
74 TO.X = \
75 (F->getAttributes(). \
76 getAttribute(AttributeSet::FunctionIndex, \
77 Y).getValueAsString() == "true"); \
78 } while (0)
79
80 RESET_OPTION(NoFramePointerElim, "no-frame-pointer-elim");
81 RESET_OPTION(LessPreciseFPMADOption, "less-precise-fpmad");
82 RESET_OPTION(UnsafeFPMath, "unsafe-fp-math");
83 RESET_OPTION(NoInfsFPMath, "no-infs-fp-math");
84 RESET_OPTION(NoNaNsFPMath, "no-nans-fp-math");
85 RESET_OPTION(UseSoftFloat, "use-soft-float");
86 RESET_OPTION(DisableTailCalls, "disable-tail-calls");
87 }
88
89 /// getRelocationModel - Returns the code generation relocation model. The
90 /// choices are static, PIC, and dynamic-no-pic, and target default.
getRelocationModel() const91 Reloc::Model TargetMachine::getRelocationModel() const {
92 if (!CodeGenInfo)
93 return Reloc::Default;
94 return CodeGenInfo->getRelocationModel();
95 }
96
97 /// getCodeModel - Returns the code model. The choices are small, kernel,
98 /// medium, large, and target default.
getCodeModel() const99 CodeModel::Model TargetMachine::getCodeModel() const {
100 if (!CodeGenInfo)
101 return CodeModel::Default;
102 return CodeGenInfo->getCodeModel();
103 }
104
105 /// Get the IR-specified TLS model for Var.
getSelectedTLSModel(const GlobalVariable * Var)106 static TLSModel::Model getSelectedTLSModel(const GlobalVariable *Var) {
107 switch (Var->getThreadLocalMode()) {
108 case GlobalVariable::NotThreadLocal:
109 llvm_unreachable("getSelectedTLSModel for non-TLS variable");
110 break;
111 case GlobalVariable::GeneralDynamicTLSModel:
112 return TLSModel::GeneralDynamic;
113 case GlobalVariable::LocalDynamicTLSModel:
114 return TLSModel::LocalDynamic;
115 case GlobalVariable::InitialExecTLSModel:
116 return TLSModel::InitialExec;
117 case GlobalVariable::LocalExecTLSModel:
118 return TLSModel::LocalExec;
119 }
120 llvm_unreachable("invalid TLS model");
121 }
122
getTLSModel(const GlobalValue * GV) const123 TLSModel::Model TargetMachine::getTLSModel(const GlobalValue *GV) const {
124 // If GV is an alias then use the aliasee for determining
125 // thread-localness.
126 if (const GlobalAlias *GA = dyn_cast<GlobalAlias>(GV))
127 GV = GA->resolveAliasedGlobal(false);
128 const GlobalVariable *Var = cast<GlobalVariable>(GV);
129
130 bool isLocal = Var->hasLocalLinkage();
131 bool isDeclaration = Var->isDeclaration();
132 bool isPIC = getRelocationModel() == Reloc::PIC_;
133 bool isPIE = Options.PositionIndependentExecutable;
134 // FIXME: what should we do for protected and internal visibility?
135 // For variables, is internal different from hidden?
136 bool isHidden = Var->hasHiddenVisibility();
137
138 TLSModel::Model Model;
139 if (isPIC && !isPIE) {
140 if (isLocal || isHidden)
141 Model = TLSModel::LocalDynamic;
142 else
143 Model = TLSModel::GeneralDynamic;
144 } else {
145 if (!isDeclaration || isHidden)
146 Model = TLSModel::LocalExec;
147 else
148 Model = TLSModel::InitialExec;
149 }
150
151 // If the user specified a more specific model, use that.
152 TLSModel::Model SelectedModel = getSelectedTLSModel(Var);
153 if (SelectedModel > Model)
154 return SelectedModel;
155
156 return Model;
157 }
158
159 /// getOptLevel - Returns the optimization level: None, Less,
160 /// Default, or Aggressive.
getOptLevel() const161 CodeGenOpt::Level TargetMachine::getOptLevel() const {
162 if (!CodeGenInfo)
163 return CodeGenOpt::Default;
164 return CodeGenInfo->getOptLevel();
165 }
166
getAsmVerbosityDefault()167 bool TargetMachine::getAsmVerbosityDefault() {
168 return AsmVerbosityDefault;
169 }
170
setAsmVerbosityDefault(bool V)171 void TargetMachine::setAsmVerbosityDefault(bool V) {
172 AsmVerbosityDefault = V;
173 }
174
getFunctionSections()175 bool TargetMachine::getFunctionSections() {
176 return FunctionSections;
177 }
178
getDataSections()179 bool TargetMachine::getDataSections() {
180 return DataSections;
181 }
182
setFunctionSections(bool V)183 void TargetMachine::setFunctionSections(bool V) {
184 FunctionSections = V;
185 }
186
setDataSections(bool V)187 void TargetMachine::setDataSections(bool V) {
188 DataSections = V;
189 }
190