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"
34using namespace llvm;
35
36//---------------------------------------------------------------------------
37// TargetMachine Class
38//
39
40TargetMachine::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
48TargetMachine::~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.
62void 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.
77Reloc::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.
85CodeModel::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.
92static 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
109TLSModel::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.
141CodeGenOpt::Level TargetMachine::getOptLevel() const {
142  if (!CodeGenInfo)
143    return CodeGenOpt::Default;
144  return CodeGenInfo->getOptLevel();
145}
146
147void TargetMachine::setOptLevel(CodeGenOpt::Level Level) const {
148  if (CodeGenInfo)
149    CodeGenInfo->setOptLevel(Level);
150}
151
152TargetIRAnalysis TargetMachine::getTargetIRAnalysis() {
153  return TargetIRAnalysis([this](const Function &F) {
154    return TargetTransformInfo(F.getParent()->getDataLayout());
155  });
156}
157
158void 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
171MCSymbol *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