1 //===-- X86TargetMachine.cpp - Define TargetMachine for the X86 -----------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines the X86 specific subclass of TargetMachine.
12 //===----------------------------------------------------------------------===//
14 #include "X86MCAsmInfo.h"
15 #include "X86TargetMachine.h"
17 #include "llvm/PassManager.h"
18 #include "llvm/CodeGen/MachineFunction.h"
19 #include "llvm/CodeGen/Passes.h"
20 #include "llvm/Support/FormattedStream.h"
21 #include "llvm/Target/TargetOptions.h"
22 #include "llvm/Target/TargetRegistry.h"
25 static const MCAsmInfo *createMCAsmInfo(const Target &T, StringRef TT) {
27 switch (TheTriple.getOS()) {
29 return new X86MCAsmInfoDarwin(TheTriple);
33 return new X86MCAsmInfoCOFF(TheTriple);
35 return new X86WinMCAsmInfo(TheTriple);
37 return new X86ELFMCAsmInfo(TheTriple);
41 extern "C" void LLVMInitializeX86Target() {
42 // Register the target.
43 RegisterTargetMachine<X86_32TargetMachine> X(TheX86_32Target);
44 RegisterTargetMachine<X86_64TargetMachine> Y(TheX86_64Target);
46 // Register the target asm info.
47 RegisterAsmInfoFn A(TheX86_32Target, createMCAsmInfo);
48 RegisterAsmInfoFn B(TheX86_64Target, createMCAsmInfo);
50 // Register the code emitter.
51 TargetRegistry::RegisterCodeEmitter(TheX86_32Target, createX86MCCodeEmitter);
52 TargetRegistry::RegisterCodeEmitter(TheX86_64Target, createX86MCCodeEmitter);
56 X86_32TargetMachine::X86_32TargetMachine(const Target &T, const std::string &TT,
57 const std::string &FS)
58 : X86TargetMachine(T, TT, FS, false) {
62 X86_64TargetMachine::X86_64TargetMachine(const Target &T, const std::string &TT,
63 const std::string &FS)
64 : X86TargetMachine(T, TT, FS, true) {
67 /// X86TargetMachine ctor - Create an X86 target.
69 X86TargetMachine::X86TargetMachine(const Target &T, const std::string &TT,
70 const std::string &FS, bool is64Bit)
71 : LLVMTargetMachine(T, TT),
72 Subtarget(TT, FS, is64Bit),
73 DataLayout(Subtarget.getDataLayout()),
74 FrameInfo(TargetFrameInfo::StackGrowsDown,
75 Subtarget.getStackAlignment(),
76 (Subtarget.isTargetWin64() ? -40 :
77 (Subtarget.is64Bit() ? -8 : -4))),
78 InstrInfo(*this), JITInfo(*this), TLInfo(*this), ELFWriterInfo(*this) {
79 DefRelocModel = getRelocationModel();
81 // If no relocation model was picked, default as appropriate for the target.
82 if (getRelocationModel() == Reloc::Default) {
83 if (!Subtarget.isTargetDarwin())
84 setRelocationModel(Reloc::Static);
85 else if (Subtarget.is64Bit())
86 setRelocationModel(Reloc::PIC_);
88 setRelocationModel(Reloc::DynamicNoPIC);
91 assert(getRelocationModel() != Reloc::Default &&
92 "Relocation mode not picked");
94 // ELF and X86-64 don't have a distinct DynamicNoPIC model. DynamicNoPIC
95 // is defined as a model for code which may be used in static or dynamic
96 // executables but not necessarily a shared library. On X86-32 we just
97 // compile in -static mode, in x86-64 we use PIC.
98 if (getRelocationModel() == Reloc::DynamicNoPIC) {
100 setRelocationModel(Reloc::PIC_);
101 else if (!Subtarget.isTargetDarwin())
102 setRelocationModel(Reloc::Static);
105 // If we are on Darwin, disallow static relocation model in X86-64 mode, since
106 // the Mach-O file format doesn't support it.
107 if (getRelocationModel() == Reloc::Static &&
108 Subtarget.isTargetDarwin() &&
110 setRelocationModel(Reloc::PIC_);
112 // Determine the PICStyle based on the target selected.
113 if (getRelocationModel() == Reloc::Static) {
114 // Unless we're in PIC or DynamicNoPIC mode, set the PIC style to None.
115 Subtarget.setPICStyle(PICStyles::None);
116 } else if (Subtarget.isTargetCygMing()) {
117 Subtarget.setPICStyle(PICStyles::None);
118 } else if (Subtarget.isTargetDarwin()) {
119 if (Subtarget.is64Bit())
120 Subtarget.setPICStyle(PICStyles::RIPRel);
121 else if (getRelocationModel() == Reloc::PIC_)
122 Subtarget.setPICStyle(PICStyles::StubPIC);
124 assert(getRelocationModel() == Reloc::DynamicNoPIC);
125 Subtarget.setPICStyle(PICStyles::StubDynamicNoPIC);
127 } else if (Subtarget.isTargetELF()) {
128 if (Subtarget.is64Bit())
129 Subtarget.setPICStyle(PICStyles::RIPRel);
131 Subtarget.setPICStyle(PICStyles::GOT);
134 // Finally, if we have "none" as our PIC style, force to static mode.
135 if (Subtarget.getPICStyle() == PICStyles::None)
136 setRelocationModel(Reloc::Static);
139 //===----------------------------------------------------------------------===//
140 // Pass Pipeline Configuration
141 //===----------------------------------------------------------------------===//
143 bool X86TargetMachine::addInstSelector(PassManagerBase &PM,
144 CodeGenOpt::Level OptLevel) {
145 // Install an instruction selector.
146 PM.add(createX86ISelDag(*this, OptLevel));
148 // If we're using Fast-ISel, clean up the mess.
150 PM.add(createDeadMachineInstructionElimPass());
152 // Install a pass to insert x87 FP_REG_KILL instructions, as needed.
153 PM.add(createX87FPRegKillInserterPass());
158 bool X86TargetMachine::addPreRegAlloc(PassManagerBase &PM,
159 CodeGenOpt::Level OptLevel) {
160 return false; // -print-machineinstr shouldn't print after this.
163 bool X86TargetMachine::addPostRegAlloc(PassManagerBase &PM,
164 CodeGenOpt::Level OptLevel) {
165 PM.add(createX86FloatingPointStackifierPass());
166 return true; // -print-machineinstr should print after this.
169 bool X86TargetMachine::addCodeEmitter(PassManagerBase &PM,
170 CodeGenOpt::Level OptLevel,
171 MachineCodeEmitter &MCE) {
172 // FIXME: Move this to TargetJITInfo!
173 // On Darwin, do not override 64-bit setting made in X86TargetMachine().
174 if (DefRelocModel == Reloc::Default &&
175 (!Subtarget.isTargetDarwin() || !Subtarget.is64Bit())) {
176 setRelocationModel(Reloc::Static);
177 Subtarget.setPICStyle(PICStyles::None);
180 PM.add(createX86CodeEmitterPass(*this, MCE));
185 bool X86TargetMachine::addCodeEmitter(PassManagerBase &PM,
186 CodeGenOpt::Level OptLevel,
187 JITCodeEmitter &JCE) {
188 // FIXME: Move this to TargetJITInfo!
189 // On Darwin, do not override 64-bit setting made in X86TargetMachine().
190 if (DefRelocModel == Reloc::Default &&
191 (!Subtarget.isTargetDarwin() || !Subtarget.is64Bit())) {
192 setRelocationModel(Reloc::Static);
193 Subtarget.setPICStyle(PICStyles::None);
197 PM.add(createX86JITCodeEmitterPass(*this, JCE));
202 bool X86TargetMachine::addCodeEmitter(PassManagerBase &PM,
203 CodeGenOpt::Level OptLevel,
204 ObjectCodeEmitter &OCE) {
205 PM.add(createX86ObjectCodeEmitterPass(*this, OCE));
209 void X86TargetMachine::setCodeModelForStatic() {
211 if (getCodeModel() != CodeModel::Default) return;
213 // For static codegen, if we're not already set, use Small codegen.
214 setCodeModel(CodeModel::Small);
218 void X86TargetMachine::setCodeModelForJIT() {
220 if (getCodeModel() != CodeModel::Default) return;
222 // 64-bit JIT places everything in the same buffer except external functions.
223 if (Subtarget.is64Bit())
224 setCodeModel(CodeModel::Large);
226 setCodeModel(CodeModel::Small);
229 /// getLSDAEncoding - Returns the LSDA pointer encoding. The choices are 4-byte,
230 /// 8-byte, and target default. The CIE is hard-coded to indicate that the LSDA
231 /// pointer in the FDE section is an "sdata4", and should be encoded as a 4-byte
232 /// pointer by default. However, some systems may require a different size due
233 /// to bugs or other conditions. We will default to a 4-byte encoding unless the
234 /// system tells us otherwise.
236 /// The issue is when the CIE says their is an LSDA. That mandates that every
237 /// FDE have an LSDA slot. But if the function does not need an LSDA. There
238 /// needs to be some way to signify there is none. The LSDA is encoded as
239 /// pc-rel. But you don't look for some magic value after adding the pc. You
240 /// have to look for a zero before adding the pc. The problem is that the size
241 /// of the zero to look for depends on the encoding. The unwinder bug in SL is
242 /// that it always checks for a pointer-size zero. So on x86_64 it looks for 8
243 /// bytes of zero. If you have an LSDA, it works fine since the 8-bytes are
244 /// non-zero so it goes ahead and then reads the value based on the encoding.
245 /// But if you use sdata4 and there is no LSDA, then the test for zero gives a
246 /// false negative and the unwinder thinks there is an LSDA.
248 /// FIXME: This call-back isn't good! We should be using the correct encoding
249 /// regardless of the system. However, there are some systems which have bugs
250 /// that prevent this from occuring.
251 DwarfLSDAEncoding::Encoding X86TargetMachine::getLSDAEncoding() const {
252 if (Subtarget.isTargetDarwin() && Subtarget.getDarwinVers() != 10)
253 return DwarfLSDAEncoding::Default;
255 return DwarfLSDAEncoding::EightByte;