TargetMachine.cpp revision 54075bbea7e70fea6cdb9e5e89b066118c1d314b 
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"
23using namespace llvm;
24
25//---------------------------------------------------------------------------
26// Command-line options that tend to be useful on more than one back-end.
27//
28
29namespace llvm {
30  bool HasDivModLibcall;
31  bool AsmVerbosityDefault(false);
32}
33
34static cl::opt<bool>
35DataSections("fdata-sections",
36  cl::desc("Emit data into separate sections"),
37  cl::init(false));
38static cl::opt<bool>
39FunctionSections("ffunction-sections",
40  cl::desc("Emit functions into separate sections"),
41  cl::init(false));
42
43//---------------------------------------------------------------------------
44// TargetMachine Class
45//
46
47TargetMachine::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
61TargetMachine::~TargetMachine() {
62  delete CodeGenInfo;
63  delete AsmInfo;
64}
65
66/// \brief Reset the target options based on the function's attributes.
67void 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.
91Reloc::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.
99CodeModel::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.
106static 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
123TLSModel::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.
161CodeGenOpt::Level TargetMachine::getOptLevel() const {
162  if (!CodeGenInfo)
163    return CodeGenOpt::Default;
164  return CodeGenInfo->getOptLevel();
165}
166
167bool TargetMachine::getAsmVerbosityDefault() {
168  return AsmVerbosityDefault;
169}
170
171void TargetMachine::setAsmVerbosityDefault(bool V) {
172  AsmVerbosityDefault = V;
173}
174
175bool TargetMachine::getFunctionSections() {
176  return FunctionSections;
177}
178
179bool TargetMachine::getDataSections() {
180  return DataSections;
181}
182
183void TargetMachine::setFunctionSections(bool V) {
184  FunctionSections = V;
185}
186
187void TargetMachine::setDataSections(bool V) {
188  DataSections = V;
189}
190