X86TargetMachine.cpp revision 276479 
1//===-- X86TargetMachine.cpp - Define TargetMachine for the X86 -----------===//
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 defines the X86 specific subclass of TargetMachine.
11//
12//===----------------------------------------------------------------------===//
13
14#include "X86TargetMachine.h"
15#include "X86.h"
16#include "llvm/CodeGen/Passes.h"
17#include "llvm/PassManager.h"
18#include "llvm/Support/CommandLine.h"
19#include "llvm/Support/FormattedStream.h"
20#include "llvm/Support/TargetRegistry.h"
21#include "llvm/Target/TargetOptions.h"
22using namespace llvm;
23
24extern "C" void LLVMInitializeX86Target() {
25  // Register the target.
26  RegisterTargetMachine<X86TargetMachine> X(TheX86_32Target);
27  RegisterTargetMachine<X86TargetMachine> Y(TheX86_64Target);
28}
29
30void X86TargetMachine::anchor() { }
31
32/// X86TargetMachine ctor - Create an X86 target.
33///
34X86TargetMachine::X86TargetMachine(const Target &T, StringRef TT, StringRef CPU,
35                                   StringRef FS, const TargetOptions &Options,
36                                   Reloc::Model RM, CodeModel::Model CM,
37                                   CodeGenOpt::Level OL)
38    : LLVMTargetMachine(T, TT, CPU, FS, Options, RM, CM, OL),
39      Subtarget(TT, CPU, FS, *this, Options.StackAlignmentOverride) {
40  // Determine the PICStyle based on the target selected.
41  if (getRelocationModel() == Reloc::Static) {
42    // Unless we're in PIC or DynamicNoPIC mode, set the PIC style to None.
43    Subtarget.setPICStyle(PICStyles::None);
44  } else if (Subtarget.is64Bit()) {
45    // PIC in 64 bit mode is always rip-rel.
46    Subtarget.setPICStyle(PICStyles::RIPRel);
47  } else if (Subtarget.isTargetCOFF()) {
48    Subtarget.setPICStyle(PICStyles::None);
49  } else if (Subtarget.isTargetDarwin()) {
50    if (getRelocationModel() == Reloc::PIC_)
51      Subtarget.setPICStyle(PICStyles::StubPIC);
52    else {
53      assert(getRelocationModel() == Reloc::DynamicNoPIC);
54      Subtarget.setPICStyle(PICStyles::StubDynamicNoPIC);
55    }
56  } else if (Subtarget.isTargetELF()) {
57    Subtarget.setPICStyle(PICStyles::GOT);
58  }
59
60  // default to hard float ABI
61  if (Options.FloatABIType == FloatABI::Default)
62    this->Options.FloatABIType = FloatABI::Hard;
63
64  // Windows stack unwinder gets confused when execution flow "falls through"
65  // after a call to 'noreturn' function.
66  // To prevent that, we emit a trap for 'unreachable' IR instructions.
67  // (which on X86, happens to be the 'ud2' instruction)
68  if (Subtarget.isTargetWin64())
69    this->Options.TrapUnreachable = true;
70
71  initAsmInfo();
72}
73
74//===----------------------------------------------------------------------===//
75// Command line options for x86
76//===----------------------------------------------------------------------===//
77static cl::opt<bool>
78UseVZeroUpper("x86-use-vzeroupper", cl::Hidden,
79  cl::desc("Minimize AVX to SSE transition penalty"),
80  cl::init(true));
81
82//===----------------------------------------------------------------------===//
83// X86 Analysis Pass Setup
84//===----------------------------------------------------------------------===//
85
86void X86TargetMachine::addAnalysisPasses(PassManagerBase &PM) {
87  // Add first the target-independent BasicTTI pass, then our X86 pass. This
88  // allows the X86 pass to delegate to the target independent layer when
89  // appropriate.
90  PM.add(createBasicTargetTransformInfoPass(this));
91  PM.add(createX86TargetTransformInfoPass(this));
92}
93
94
95//===----------------------------------------------------------------------===//
96// Pass Pipeline Configuration
97//===----------------------------------------------------------------------===//
98
99namespace {
100/// X86 Code Generator Pass Configuration Options.
101class X86PassConfig : public TargetPassConfig {
102public:
103  X86PassConfig(X86TargetMachine *TM, PassManagerBase &PM)
104    : TargetPassConfig(TM, PM) {}
105
106  X86TargetMachine &getX86TargetMachine() const {
107    return getTM<X86TargetMachine>();
108  }
109
110  const X86Subtarget &getX86Subtarget() const {
111    return *getX86TargetMachine().getSubtargetImpl();
112  }
113
114  void addIRPasses() override;
115  bool addInstSelector() override;
116  bool addILPOpts() override;
117  bool addPreRegAlloc() override;
118  bool addPostRegAlloc() override;
119  bool addPreEmitPass() override;
120};
121} // namespace
122
123TargetPassConfig *X86TargetMachine::createPassConfig(PassManagerBase &PM) {
124  return new X86PassConfig(this, PM);
125}
126
127void X86PassConfig::addIRPasses() {
128  addPass(createX86AtomicExpandPass(&getX86TargetMachine()));
129
130  TargetPassConfig::addIRPasses();
131}
132
133bool X86PassConfig::addInstSelector() {
134  // Install an instruction selector.
135  addPass(createX86ISelDag(getX86TargetMachine(), getOptLevel()));
136
137  // For ELF, cleanup any local-dynamic TLS accesses.
138  if (getX86Subtarget().isTargetELF() && getOptLevel() != CodeGenOpt::None)
139    addPass(createCleanupLocalDynamicTLSPass());
140
141  addPass(createX86GlobalBaseRegPass());
142
143  return false;
144}
145
146bool X86PassConfig::addILPOpts() {
147  addPass(&EarlyIfConverterID);
148  return true;
149}
150
151bool X86PassConfig::addPreRegAlloc() {
152  return false;  // -print-machineinstr shouldn't print after this.
153}
154
155bool X86PassConfig::addPostRegAlloc() {
156  addPass(createX86FloatingPointStackifierPass());
157  return true;  // -print-machineinstr should print after this.
158}
159
160bool X86PassConfig::addPreEmitPass() {
161  bool ShouldPrint = false;
162  if (getOptLevel() != CodeGenOpt::None && getX86Subtarget().hasSSE2()) {
163    addPass(createExecutionDependencyFixPass(&X86::VR128RegClass));
164    ShouldPrint = true;
165  }
166
167  if (UseVZeroUpper) {
168    addPass(createX86IssueVZeroUpperPass());
169    ShouldPrint = true;
170  }
171
172  if (getOptLevel() != CodeGenOpt::None) {
173    addPass(createX86PadShortFunctions());
174    addPass(createX86FixupLEAs());
175    ShouldPrint = true;
176  }
177
178  return ShouldPrint;
179}
180
181bool X86TargetMachine::addCodeEmitter(PassManagerBase &PM,
182                                      JITCodeEmitter &JCE) {
183  PM.add(createX86JITCodeEmitterPass(*this, JCE));
184
185  return false;
186}
187