TargetMachine.cpp revision dce4a407a24b04eebc6a376f8e62b41aaa7b071f 
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"
29using namespace llvm;
30
31//---------------------------------------------------------------------------
32// TargetMachine Class
33//
34
35TargetMachine::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
44TargetMachine::~TargetMachine() {
45  delete CodeGenInfo;
46  delete AsmInfo;
47}
48
49/// \brief Reset the target options based on the function's attributes.
50void 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.
76Reloc::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.
84CodeModel::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.
91static TLSModel::Model getSelectedTLSModel(const GlobalVariable *Var) {
92  switch (Var->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
108TLSModel::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  const GlobalVariable *Var = dyn_cast<GlobalVariable>(GV);
131  if (Var) {
132    // If the user specified a more specific model, use that.
133    TLSModel::Model SelectedModel = getSelectedTLSModel(Var);
134    if (SelectedModel > Model)
135      return SelectedModel;
136  }
137
138  return Model;
139}
140
141/// getOptLevel - Returns the optimization level: None, Less,
142/// Default, or Aggressive.
143CodeGenOpt::Level TargetMachine::getOptLevel() const {
144  if (!CodeGenInfo)
145    return CodeGenOpt::Default;
146  return CodeGenInfo->getOptLevel();
147}
148
149void TargetMachine::setOptLevel(CodeGenOpt::Level Level) const {
150  if (CodeGenInfo)
151    CodeGenInfo->setOptLevel(Level);
152}
153
154bool TargetMachine::getAsmVerbosityDefault() const {
155  return Options.MCOptions.AsmVerbose;
156}
157
158void TargetMachine::setAsmVerbosityDefault(bool V) {
159  Options.MCOptions.AsmVerbose = V;
160}
161
162bool TargetMachine::getFunctionSections() const {
163  return Options.FunctionSections;
164}
165
166bool TargetMachine::getDataSections() const {
167  return Options.DataSections;
168}
169
170void TargetMachine::setFunctionSections(bool V) {
171  Options.FunctionSections = V;
172}
173
174void TargetMachine::setDataSections(bool V) {
175  Options.DataSections = V;
176}
177
178void TargetMachine::getNameWithPrefix(SmallVectorImpl<char> &Name,
179                                      const GlobalValue *GV, Mangler &Mang,
180                                      bool MayAlwaysUsePrivate) const {
181  if (MayAlwaysUsePrivate || !GV->hasPrivateLinkage()) {
182    // Simple case: If GV is not private, it is not important to find out if
183    // private labels are legal in this case or not.
184    Mang.getNameWithPrefix(Name, GV, false);
185    return;
186  }
187  SectionKind GVKind = TargetLoweringObjectFile::getKindForGlobal(GV, *this);
188  const TargetLoweringObjectFile &TLOF =
189      getTargetLowering()->getObjFileLowering();
190  const MCSection *TheSection = TLOF.SectionForGlobal(GV, GVKind, Mang, *this);
191  bool CannotUsePrivateLabel = TLOF.isSectionAtomizableBySymbols(*TheSection);
192  Mang.getNameWithPrefix(Name, GV, CannotUsePrivateLabel);
193}
194
195MCSymbol *TargetMachine::getSymbol(const GlobalValue *GV, Mangler &Mang) const {
196  SmallString<60> NameStr;
197  getNameWithPrefix(NameStr, GV, Mang);
198  const TargetLoweringObjectFile &TLOF =
199      getTargetLowering()->getObjFileLowering();
200  return TLOF.getContext().GetOrCreateSymbol(NameStr.str());
201}
202