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 "X86MCAsmInfo.h"
15 #include "X86TargetMachine.h"
16 #include "X86.h"
17 #include "llvm/PassManager.h"
18 #include "llvm/CodeGen/MachineFunction.h"
19 #include "llvm/CodeGen/Passes.h"
20 #include "llvm/MC/MCCodeEmitter.h"
21 #include "llvm/MC/MCStreamer.h"
22 #include "llvm/Support/FormattedStream.h"
23 #include "llvm/Target/TargetOptions.h"
24 #include "llvm/Target/TargetRegistry.h"
25 using namespace llvm;
26 
27 static MCAsmInfo *createMCAsmInfo(const Target &T, StringRef TT) {
28   Triple TheTriple(TT);
29   switch (TheTriple.getOS()) {
30   case Triple::Darwin:
31     return new X86MCAsmInfoDarwin(TheTriple);
32   case Triple::MinGW32:
33   case Triple::MinGW64:
34   case Triple::Cygwin:
35   case Triple::Win32:
36     return new X86MCAsmInfoCOFF(TheTriple);
37   default:
38     return new X86ELFMCAsmInfo(TheTriple);
39   }
40 }
41 
42 static MCStreamer *createMCStreamer(const Target &T, const std::string &TT,
43                                     MCContext &Ctx, TargetAsmBackend &TAB,
44                                     raw_ostream &_OS,
45                                     MCCodeEmitter *_Emitter,
46                                     bool RelaxAll,
47                                     bool NoExecStack) {
48   Triple TheTriple(TT);
49   switch (TheTriple.getOS()) {
50   case Triple::Darwin:
51     return createMachOStreamer(Ctx, TAB, _OS, _Emitter, RelaxAll);
52   case Triple::MinGW32:
53   case Triple::MinGW64:
54   case Triple::Cygwin:
55   case Triple::Win32:
56     return createWinCOFFStreamer(Ctx, TAB, *_Emitter, _OS, RelaxAll);
57   default:
58     return createELFStreamer(Ctx, TAB, _OS, _Emitter, RelaxAll, NoExecStack);
59   }
60 }
61 
62 extern "C" void LLVMInitializeX86Target() {
63   // Register the target.
64   RegisterTargetMachine<X86_32TargetMachine> X(TheX86_32Target);
65   RegisterTargetMachine<X86_64TargetMachine> Y(TheX86_64Target);
66 
67   // Register the target asm info.
68   RegisterAsmInfoFn A(TheX86_32Target, createMCAsmInfo);
69   RegisterAsmInfoFn B(TheX86_64Target, createMCAsmInfo);
70 
71   // Register the code emitter.
72   TargetRegistry::RegisterCodeEmitter(TheX86_32Target,
73                                       createX86_32MCCodeEmitter);
74   TargetRegistry::RegisterCodeEmitter(TheX86_64Target,
75                                       createX86_64MCCodeEmitter);
76 
77   // Register the asm backend.
78   TargetRegistry::RegisterAsmBackend(TheX86_32Target,
79                                      createX86_32AsmBackend);
80   TargetRegistry::RegisterAsmBackend(TheX86_64Target,
81                                      createX86_64AsmBackend);
82 
83   // Register the object streamer.
84   TargetRegistry::RegisterObjectStreamer(TheX86_32Target,
85                                          createMCStreamer);
86   TargetRegistry::RegisterObjectStreamer(TheX86_64Target,
87                                          createMCStreamer);
88 }
89 
90 
91 X86_32TargetMachine::X86_32TargetMachine(const Target &T, const std::string &TT,
92                                          const std::string &FS)
93   : X86TargetMachine(T, TT, FS, false),
94     DataLayout(getSubtargetImpl()->isTargetDarwin() ?
95                "e-p:32:32-f64:32:64-i64:32:64-f80:128:128-n8:16:32" :
96                (getSubtargetImpl()->isTargetCygMing() ||
97                 getSubtargetImpl()->isTargetWindows()) ?
98                "e-p:32:32-f64:64:64-i64:64:64-f80:32:32-n8:16:32" :
99                "e-p:32:32-f64:32:64-i64:32:64-f80:32:32-n8:16:32"),
100     InstrInfo(*this),
101     TSInfo(*this),
102     TLInfo(*this),
103     JITInfo(*this) {
104 }
105 
106 
107 X86_64TargetMachine::X86_64TargetMachine(const Target &T, const std::string &TT,
108                                          const std::string &FS)
109   : X86TargetMachine(T, TT, FS, true),
110     DataLayout("e-p:64:64-s:64-f64:64:64-i64:64:64-f80:128:128-n8:16:32:64"),
111     InstrInfo(*this),
112     TSInfo(*this),
113     TLInfo(*this),
114     JITInfo(*this) {
115 }
116 
117 /// X86TargetMachine ctor - Create an X86 target.
118 ///
119 X86TargetMachine::X86TargetMachine(const Target &T, const std::string &TT,
120                                    const std::string &FS, bool is64Bit)
121   : LLVMTargetMachine(T, TT),
122     Subtarget(TT, FS, is64Bit),
123     FrameLowering(*this, Subtarget),
124     ELFWriterInfo(is64Bit, true) {
125   DefRelocModel = getRelocationModel();
126 
127   // If no relocation model was picked, default as appropriate for the target.
128   if (getRelocationModel() == Reloc::Default) {
129     // Darwin defaults to PIC in 64 bit mode and dynamic-no-pic in 32 bit mode.
130     // Win64 requires rip-rel addressing, thus we force it to PIC. Otherwise we
131     // use static relocation model by default.
132     if (Subtarget.isTargetDarwin()) {
133       if (Subtarget.is64Bit())
134         setRelocationModel(Reloc::PIC_);
135       else
136         setRelocationModel(Reloc::DynamicNoPIC);
137     } else if (Subtarget.isTargetWin64())
138       setRelocationModel(Reloc::PIC_);
139     else
140       setRelocationModel(Reloc::Static);
141   }
142 
143   assert(getRelocationModel() != Reloc::Default &&
144          "Relocation mode not picked");
145 
146   // ELF and X86-64 don't have a distinct DynamicNoPIC model.  DynamicNoPIC
147   // is defined as a model for code which may be used in static or dynamic
148   // executables but not necessarily a shared library. On X86-32 we just
149   // compile in -static mode, in x86-64 we use PIC.
150   if (getRelocationModel() == Reloc::DynamicNoPIC) {
151     if (is64Bit)
152       setRelocationModel(Reloc::PIC_);
153     else if (!Subtarget.isTargetDarwin())
154       setRelocationModel(Reloc::Static);
155   }
156 
157   // If we are on Darwin, disallow static relocation model in X86-64 mode, since
158   // the Mach-O file format doesn't support it.
159   if (getRelocationModel() == Reloc::Static &&
160       Subtarget.isTargetDarwin() &&
161       is64Bit)
162     setRelocationModel(Reloc::PIC_);
163 
164   // Determine the PICStyle based on the target selected.
165   if (getRelocationModel() == Reloc::Static) {
166     // Unless we're in PIC or DynamicNoPIC mode, set the PIC style to None.
167     Subtarget.setPICStyle(PICStyles::None);
168   } else if (Subtarget.is64Bit()) {
169     // PIC in 64 bit mode is always rip-rel.
170     Subtarget.setPICStyle(PICStyles::RIPRel);
171   } else if (Subtarget.isTargetCygMing()) {
172     Subtarget.setPICStyle(PICStyles::None);
173   } else if (Subtarget.isTargetDarwin()) {
174     if (getRelocationModel() == Reloc::PIC_)
175       Subtarget.setPICStyle(PICStyles::StubPIC);
176     else {
177       assert(getRelocationModel() == Reloc::DynamicNoPIC);
178       Subtarget.setPICStyle(PICStyles::StubDynamicNoPIC);
179     }
180   } else if (Subtarget.isTargetELF()) {
181     Subtarget.setPICStyle(PICStyles::GOT);
182   }
183 
184   // Finally, if we have "none" as our PIC style, force to static mode.
185   if (Subtarget.getPICStyle() == PICStyles::None)
186     setRelocationModel(Reloc::Static);
187 }
188 
189 //===----------------------------------------------------------------------===//
190 // Pass Pipeline Configuration
191 //===----------------------------------------------------------------------===//
192 
193 bool X86TargetMachine::addInstSelector(PassManagerBase &PM,
194                                        CodeGenOpt::Level OptLevel) {
195   // Install an instruction selector.
196   PM.add(createX86ISelDag(*this, OptLevel));
197 
198   // For 32-bit, prepend instructions to set the "global base reg" for PIC.
199   if (!Subtarget.is64Bit())
200     PM.add(createGlobalBaseRegPass());
201 
202   return false;
203 }
204 
205 bool X86TargetMachine::addPreRegAlloc(PassManagerBase &PM,
206                                       CodeGenOpt::Level OptLevel) {
207   PM.add(createX86MaxStackAlignmentHeuristicPass());
208   return false;  // -print-machineinstr shouldn't print after this.
209 }
210 
211 bool X86TargetMachine::addPostRegAlloc(PassManagerBase &PM,
212                                        CodeGenOpt::Level OptLevel) {
213   PM.add(createX86FloatingPointStackifierPass());
214   return true;  // -print-machineinstr should print after this.
215 }
216 
217 bool X86TargetMachine::addPreEmitPass(PassManagerBase &PM,
218                                       CodeGenOpt::Level OptLevel) {
219   if (OptLevel != CodeGenOpt::None && Subtarget.hasSSE2()) {
220     PM.add(createSSEDomainFixPass());
221     return true;
222   }
223   return false;
224 }
225 
226 bool X86TargetMachine::addCodeEmitter(PassManagerBase &PM,
227                                       CodeGenOpt::Level OptLevel,
228                                       JITCodeEmitter &JCE) {
229   // FIXME: Move this to TargetJITInfo!
230   // On Darwin, do not override 64-bit setting made in X86TargetMachine().
231   if (DefRelocModel == Reloc::Default &&
232       (!Subtarget.isTargetDarwin() || !Subtarget.is64Bit())) {
233     setRelocationModel(Reloc::Static);
234     Subtarget.setPICStyle(PICStyles::None);
235   }
236 
237 
238   PM.add(createX86JITCodeEmitterPass(*this, JCE));
239 
240   return false;
241 }
242 
243 void X86TargetMachine::setCodeModelForStatic() {
244 
245     if (getCodeModel() != CodeModel::Default) return;
246 
247     // For static codegen, if we're not already set, use Small codegen.
248     setCodeModel(CodeModel::Small);
249 }
250 
251 
252 void X86TargetMachine::setCodeModelForJIT() {
253 
254   if (getCodeModel() != CodeModel::Default) return;
255 
256   // 64-bit JIT places everything in the same buffer except external functions.
257   if (Subtarget.is64Bit())
258     setCodeModel(CodeModel::Large);
259   else
260     setCodeModel(CodeModel::Small);
261 }
262