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   Triple TheTriple(TT);
48   switch (TheTriple.getOS()) {
49   case Triple::Darwin:
50     return createMachOStreamer(Ctx, TAB, _OS, _Emitter, RelaxAll);
51   case Triple::MinGW32:
52   case Triple::MinGW64:
53   case Triple::Cygwin:
54   case Triple::Win32:
55     return createWinCOFFStreamer(Ctx, TAB, *_Emitter, _OS, RelaxAll);
56   default:
57     return createELFStreamer(Ctx, TAB, _OS, _Emitter, RelaxAll);
58   }
59 }
60 
61 extern "C" void LLVMInitializeX86Target() {
62   // Register the target.
63   RegisterTargetMachine<X86_32TargetMachine> X(TheX86_32Target);
64   RegisterTargetMachine<X86_64TargetMachine> Y(TheX86_64Target);
65 
66   // Register the target asm info.
67   RegisterAsmInfoFn A(TheX86_32Target, createMCAsmInfo);
68   RegisterAsmInfoFn B(TheX86_64Target, createMCAsmInfo);
69 
70   // Register the code emitter.
71   TargetRegistry::RegisterCodeEmitter(TheX86_32Target,
72                                       createX86_32MCCodeEmitter);
73   TargetRegistry::RegisterCodeEmitter(TheX86_64Target,
74                                       createX86_64MCCodeEmitter);
75 
76   // Register the asm backend.
77   TargetRegistry::RegisterAsmBackend(TheX86_32Target,
78                                      createX86_32AsmBackend);
79   TargetRegistry::RegisterAsmBackend(TheX86_64Target,
80                                      createX86_64AsmBackend);
81 
82   // Register the object streamer.
83   TargetRegistry::RegisterObjectStreamer(TheX86_32Target,
84                                          createMCStreamer);
85   TargetRegistry::RegisterObjectStreamer(TheX86_64Target,
86                                          createMCStreamer);
87 }
88 
89 
90 X86_32TargetMachine::X86_32TargetMachine(const Target &T, const std::string &TT,
91                                          const std::string &FS)
92   : X86TargetMachine(T, TT, FS, false),
93     DataLayout(getSubtargetImpl()->isTargetDarwin() ?
94                "e-p:32:32-f64:32:64-i64:32:64-f80:128:128-n8:16:32" :
95                (getSubtargetImpl()->isTargetCygMing() ||
96                 getSubtargetImpl()->isTargetWindows()) ?
97                "e-p:32:32-f64:64:64-i64:64:64-f80:32:32-n8:16:32" :
98                "e-p:32:32-f64:32:64-i64:32:64-f80:32:32-n8:16:32"),
99     InstrInfo(*this),
100     TSInfo(*this),
101     TLInfo(*this),
102     JITInfo(*this) {
103 }
104 
105 
106 X86_64TargetMachine::X86_64TargetMachine(const Target &T, const std::string &TT,
107                                          const std::string &FS)
108   : X86TargetMachine(T, TT, FS, true),
109     DataLayout("e-p:64:64-s:64-f64:64:64-i64:64:64-f80:128:128-n8:16:32:64"),
110     InstrInfo(*this),
111     TSInfo(*this),
112     TLInfo(*this),
113     JITInfo(*this) {
114 }
115 
116 /// X86TargetMachine ctor - Create an X86 target.
117 ///
118 X86TargetMachine::X86TargetMachine(const Target &T, const std::string &TT,
119                                    const std::string &FS, bool is64Bit)
120   : LLVMTargetMachine(T, TT),
121     Subtarget(TT, FS, is64Bit),
122     FrameInfo(TargetFrameInfo::StackGrowsDown,
123               Subtarget.getStackAlignment(),
124               (Subtarget.isTargetWin64() ? -40 :
125                (Subtarget.is64Bit() ? -8 : -4))),
126     ELFWriterInfo(is64Bit, true) {
127   DefRelocModel = getRelocationModel();
128 
129   // If no relocation model was picked, default as appropriate for the target.
130   if (getRelocationModel() == Reloc::Default) {
131     // Darwin defaults to PIC in 64 bit mode and dynamic-no-pic in 32 bit mode.
132     // Win64 requires rip-rel addressing, thus we force it to PIC. Otherwise we
133     // use static relocation model by default.
134     if (Subtarget.isTargetDarwin()) {
135       if (Subtarget.is64Bit())
136         setRelocationModel(Reloc::PIC_);
137       else
138         setRelocationModel(Reloc::DynamicNoPIC);
139     } else if (Subtarget.isTargetWin64())
140       setRelocationModel(Reloc::PIC_);
141     else
142       setRelocationModel(Reloc::Static);
143   }
144 
145   assert(getRelocationModel() != Reloc::Default &&
146          "Relocation mode not picked");
147 
148   // ELF and X86-64 don't have a distinct DynamicNoPIC model.  DynamicNoPIC
149   // is defined as a model for code which may be used in static or dynamic
150   // executables but not necessarily a shared library. On X86-32 we just
151   // compile in -static mode, in x86-64 we use PIC.
152   if (getRelocationModel() == Reloc::DynamicNoPIC) {
153     if (is64Bit)
154       setRelocationModel(Reloc::PIC_);
155     else if (!Subtarget.isTargetDarwin())
156       setRelocationModel(Reloc::Static);
157   }
158 
159   // If we are on Darwin, disallow static relocation model in X86-64 mode, since
160   // the Mach-O file format doesn't support it.
161   if (getRelocationModel() == Reloc::Static &&
162       Subtarget.isTargetDarwin() &&
163       is64Bit)
164     setRelocationModel(Reloc::PIC_);
165 
166   // Determine the PICStyle based on the target selected.
167   if (getRelocationModel() == Reloc::Static) {
168     // Unless we're in PIC or DynamicNoPIC mode, set the PIC style to None.
169     Subtarget.setPICStyle(PICStyles::None);
170   } else if (Subtarget.is64Bit()) {
171     // PIC in 64 bit mode is always rip-rel.
172     Subtarget.setPICStyle(PICStyles::RIPRel);
173   } else if (Subtarget.isTargetCygMing()) {
174     Subtarget.setPICStyle(PICStyles::None);
175   } else if (Subtarget.isTargetDarwin()) {
176     if (getRelocationModel() == Reloc::PIC_)
177       Subtarget.setPICStyle(PICStyles::StubPIC);
178     else {
179       assert(getRelocationModel() == Reloc::DynamicNoPIC);
180       Subtarget.setPICStyle(PICStyles::StubDynamicNoPIC);
181     }
182   } else if (Subtarget.isTargetELF()) {
183     Subtarget.setPICStyle(PICStyles::GOT);
184   }
185 
186   // Finally, if we have "none" as our PIC style, force to static mode.
187   if (Subtarget.getPICStyle() == PICStyles::None)
188     setRelocationModel(Reloc::Static);
189 }
190 
191 //===----------------------------------------------------------------------===//
192 // Pass Pipeline Configuration
193 //===----------------------------------------------------------------------===//
194 
195 bool X86TargetMachine::addInstSelector(PassManagerBase &PM,
196                                        CodeGenOpt::Level OptLevel) {
197   // Install an instruction selector.
198   PM.add(createX86ISelDag(*this, OptLevel));
199 
200   // For 32-bit, prepend instructions to set the "global base reg" for PIC.
201   if (!Subtarget.is64Bit())
202     PM.add(createGlobalBaseRegPass());
203 
204   return false;
205 }
206 
207 bool X86TargetMachine::addPreRegAlloc(PassManagerBase &PM,
208                                       CodeGenOpt::Level OptLevel) {
209   PM.add(createX86MaxStackAlignmentHeuristicPass());
210   return false;  // -print-machineinstr shouldn't print after this.
211 }
212 
213 bool X86TargetMachine::addPostRegAlloc(PassManagerBase &PM,
214                                        CodeGenOpt::Level OptLevel) {
215   PM.add(createX86FloatingPointStackifierPass());
216   return true;  // -print-machineinstr should print after this.
217 }
218 
219 bool X86TargetMachine::addPreEmitPass(PassManagerBase &PM,
220                                       CodeGenOpt::Level OptLevel) {
221   if (OptLevel != CodeGenOpt::None && Subtarget.hasSSE2()) {
222     PM.add(createSSEDomainFixPass());
223     return true;
224   }
225   return false;
226 }
227 
228 bool X86TargetMachine::addCodeEmitter(PassManagerBase &PM,
229                                       CodeGenOpt::Level OptLevel,
230                                       JITCodeEmitter &JCE) {
231   // FIXME: Move this to TargetJITInfo!
232   // On Darwin, do not override 64-bit setting made in X86TargetMachine().
233   if (DefRelocModel == Reloc::Default &&
234       (!Subtarget.isTargetDarwin() || !Subtarget.is64Bit())) {
235     setRelocationModel(Reloc::Static);
236     Subtarget.setPICStyle(PICStyles::None);
237   }
238 
239 
240   PM.add(createX86JITCodeEmitterPass(*this, JCE));
241 
242   return false;
243 }
244 
245 void X86TargetMachine::setCodeModelForStatic() {
246 
247     if (getCodeModel() != CodeModel::Default) return;
248 
249     // For static codegen, if we're not already set, use Small codegen.
250     setCodeModel(CodeModel::Small);
251 }
252 
253 
254 void X86TargetMachine::setCodeModelForJIT() {
255 
256   if (getCodeModel() != CodeModel::Default) return;
257 
258   // 64-bit JIT places everything in the same buffer except external functions.
259   if (Subtarget.is64Bit())
260     setCodeModel(CodeModel::Large);
261   else
262     setCodeModel(CodeModel::Small);
263 }
264