1 //===-- LLVMTargetMachine.cpp - Implement the LLVMTargetMachine class -----===//
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 implements the LLVMTargetMachine class.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "llvm/Analysis/Passes.h"
15 #include "llvm/CodeGen/AsmPrinter.h"
16 #include "llvm/CodeGen/BasicTTIImpl.h"
17 #include "llvm/CodeGen/MachineModuleInfo.h"
18 #include "llvm/CodeGen/Passes.h"
19 #include "llvm/CodeGen/TargetLoweringObjectFile.h"
20 #include "llvm/CodeGen/TargetPassConfig.h"
21 #include "llvm/IR/LegacyPassManager.h"
22 #include "llvm/MC/MCAsmBackend.h"
23 #include "llvm/MC/MCAsmInfo.h"
24 #include "llvm/MC/MCCodeEmitter.h"
25 #include "llvm/MC/MCContext.h"
26 #include "llvm/MC/MCInstrInfo.h"
27 #include "llvm/MC/MCStreamer.h"
28 #include "llvm/MC/MCSubtargetInfo.h"
29 #include "llvm/Support/CommandLine.h"
30 #include "llvm/Support/ErrorHandling.h"
31 #include "llvm/Support/FormattedStream.h"
32 #include "llvm/Support/TargetRegistry.h"
33 #include "llvm/Target/TargetMachine.h"
34 #include "llvm/Target/TargetOptions.h"
35 using namespace llvm;
36 
37 void LLVMTargetMachine::initAsmInfo() {
38   MRI = TheTarget.createMCRegInfo(getTargetTriple().str());
39   MII = TheTarget.createMCInstrInfo();
40   // FIXME: Having an MCSubtargetInfo on the target machine is a hack due
41   // to some backends having subtarget feature dependent module level
42   // code generation. This is similar to the hack in the AsmPrinter for
43   // module level assembly etc.
44   STI = TheTarget.createMCSubtargetInfo(getTargetTriple().str(), getTargetCPU(),
45                                         getTargetFeatureString());
46 
47   MCAsmInfo *TmpAsmInfo =
48       TheTarget.createMCAsmInfo(*MRI, getTargetTriple().str());
49   // TargetSelect.h moved to a different directory between LLVM 2.9 and 3.0,
50   // and if the old one gets included then MCAsmInfo will be NULL and
51   // we'll crash later.
52   // Provide the user with a useful error message about what's wrong.
53   assert(TmpAsmInfo && "MCAsmInfo not initialized. "
54          "Make sure you include the correct TargetSelect.h"
55          "and that InitializeAllTargetMCs() is being invoked!");
56 
57   if (Options.DisableIntegratedAS)
58     TmpAsmInfo->setUseIntegratedAssembler(false);
59 
60   TmpAsmInfo->setPreserveAsmComments(Options.MCOptions.PreserveAsmComments);
61 
62   TmpAsmInfo->setCompressDebugSections(Options.CompressDebugSections);
63 
64   TmpAsmInfo->setRelaxELFRelocations(Options.RelaxELFRelocations);
65 
66   if (Options.ExceptionModel != ExceptionHandling::None)
67     TmpAsmInfo->setExceptionsType(Options.ExceptionModel);
68 
69   AsmInfo = TmpAsmInfo;
70 }
71 
72 LLVMTargetMachine::LLVMTargetMachine(const Target &T,
73                                      StringRef DataLayoutString,
74                                      const Triple &TT, StringRef CPU,
75                                      StringRef FS, const TargetOptions &Options,
76                                      Reloc::Model RM, CodeModel::Model CM,
77                                      CodeGenOpt::Level OL)
78     : TargetMachine(T, DataLayoutString, TT, CPU, FS, Options) {
79   this->RM = RM;
80   this->CMModel = CM;
81   this->OptLevel = OL;
82 }
83 
84 TargetTransformInfo
85 LLVMTargetMachine::getTargetTransformInfo(const Function &F) {
86   return TargetTransformInfo(BasicTTIImpl(this, F));
87 }
88 
89 /// addPassesToX helper drives creation and initialization of TargetPassConfig.
90 static MCContext *
91 addPassesToGenerateCode(LLVMTargetMachine *TM, PassManagerBase &PM,
92                         bool DisableVerify, bool &WillCompleteCodeGenPipeline,
93                         raw_pwrite_stream &Out, MachineModuleInfo *MMI) {
94   // Targets may override createPassConfig to provide a target-specific
95   // subclass.
96   TargetPassConfig *PassConfig = TM->createPassConfig(PM);
97   // Set PassConfig options provided by TargetMachine.
98   PassConfig->setDisableVerify(DisableVerify);
99   WillCompleteCodeGenPipeline = PassConfig->willCompleteCodeGenPipeline();
100   PM.add(PassConfig);
101   if (!MMI)
102     MMI = new MachineModuleInfo(TM);
103   PM.add(MMI);
104 
105   if (PassConfig->addISelPasses())
106     return nullptr;
107   PassConfig->addMachinePasses();
108   PassConfig->setInitialized();
109   if (!WillCompleteCodeGenPipeline)
110     PM.add(createPrintMIRPass(Out));
111 
112   return &MMI->getContext();
113 }
114 
115 bool LLVMTargetMachine::addAsmPrinter(PassManagerBase &PM,
116     raw_pwrite_stream &Out, CodeGenFileType FileType,
117     MCContext &Context) {
118   if (Options.MCOptions.MCSaveTempLabels)
119     Context.setAllowTemporaryLabels(false);
120 
121   const MCSubtargetInfo &STI = *getMCSubtargetInfo();
122   const MCAsmInfo &MAI = *getMCAsmInfo();
123   const MCRegisterInfo &MRI = *getMCRegisterInfo();
124   const MCInstrInfo &MII = *getMCInstrInfo();
125 
126   std::unique_ptr<MCStreamer> AsmStreamer;
127 
128   switch (FileType) {
129   case CGFT_AssemblyFile: {
130     MCInstPrinter *InstPrinter = getTarget().createMCInstPrinter(
131         getTargetTriple(), MAI.getAssemblerDialect(), MAI, MII, MRI);
132 
133     // Create a code emitter if asked to show the encoding.
134     MCCodeEmitter *MCE = nullptr;
135     if (Options.MCOptions.ShowMCEncoding)
136       MCE = getTarget().createMCCodeEmitter(MII, MRI, Context);
137 
138     MCAsmBackend *MAB =
139         getTarget().createMCAsmBackend(STI, MRI, Options.MCOptions);
140     auto FOut = llvm::make_unique<formatted_raw_ostream>(Out);
141     MCStreamer *S = getTarget().createAsmStreamer(
142         Context, std::move(FOut), Options.MCOptions.AsmVerbose,
143         Options.MCOptions.MCUseDwarfDirectory, InstPrinter, MCE, MAB,
144         Options.MCOptions.ShowMCInst);
145     AsmStreamer.reset(S);
146     break;
147   }
148   case CGFT_ObjectFile: {
149     // Create the code emitter for the target if it exists.  If not, .o file
150     // emission fails.
151     MCCodeEmitter *MCE = getTarget().createMCCodeEmitter(MII, MRI, Context);
152     MCAsmBackend *MAB =
153         getTarget().createMCAsmBackend(STI, MRI, Options.MCOptions);
154     if (!MCE || !MAB)
155       return true;
156 
157     // Don't waste memory on names of temp labels.
158     Context.setUseNamesOnTempLabels(false);
159 
160     Triple T(getTargetTriple().str());
161     AsmStreamer.reset(getTarget().createMCObjectStreamer(
162         T, Context, std::unique_ptr<MCAsmBackend>(MAB), Out,
163         std::unique_ptr<MCCodeEmitter>(MCE), STI, Options.MCOptions.MCRelaxAll,
164         Options.MCOptions.MCIncrementalLinkerCompatible,
165         /*DWARFMustBeAtTheEnd*/ true));
166     break;
167   }
168   case CGFT_Null:
169     // The Null output is intended for use for performance analysis and testing,
170     // not real users.
171     AsmStreamer.reset(getTarget().createNullStreamer(Context));
172     break;
173   }
174 
175   // Create the AsmPrinter, which takes ownership of AsmStreamer if successful.
176   FunctionPass *Printer =
177       getTarget().createAsmPrinter(*this, std::move(AsmStreamer));
178   if (!Printer)
179     return true;
180 
181   PM.add(Printer);
182   return false;
183 }
184 
185 bool LLVMTargetMachine::addPassesToEmitFile(PassManagerBase &PM,
186                                             raw_pwrite_stream &Out,
187                                             CodeGenFileType FileType,
188                                             bool DisableVerify,
189                                             MachineModuleInfo *MMI) {
190   // Add common CodeGen passes.
191   bool WillCompleteCodeGenPipeline = true;
192   MCContext *Context = addPassesToGenerateCode(
193       this, PM, DisableVerify, WillCompleteCodeGenPipeline, Out, MMI);
194   if (!Context)
195     return true;
196 
197   if (WillCompleteCodeGenPipeline && addAsmPrinter(PM, Out, FileType, *Context))
198     return true;
199 
200   PM.add(createFreeMachineFunctionPass());
201   return false;
202 }
203 
204 /// addPassesToEmitMC - Add passes to the specified pass manager to get
205 /// machine code emitted with the MCJIT. This method returns true if machine
206 /// code is not supported. It fills the MCContext Ctx pointer which can be
207 /// used to build custom MCStreamer.
208 ///
209 bool LLVMTargetMachine::addPassesToEmitMC(PassManagerBase &PM, MCContext *&Ctx,
210                                           raw_pwrite_stream &Out,
211                                           bool DisableVerify) {
212   // Add common CodeGen passes.
213   bool WillCompleteCodeGenPipeline = true;
214   Ctx = addPassesToGenerateCode(this, PM, DisableVerify,
215                                 WillCompleteCodeGenPipeline, Out,
216                                 /*MachineModuleInfo*/ nullptr);
217   if (!Ctx)
218     return true;
219   assert(WillCompleteCodeGenPipeline && "CodeGen pipeline has been altered");
220 
221   if (Options.MCOptions.MCSaveTempLabels)
222     Ctx->setAllowTemporaryLabels(false);
223 
224   // Create the code emitter for the target if it exists.  If not, .o file
225   // emission fails.
226   const MCSubtargetInfo &STI = *getMCSubtargetInfo();
227   const MCRegisterInfo &MRI = *getMCRegisterInfo();
228   MCCodeEmitter *MCE =
229       getTarget().createMCCodeEmitter(*getMCInstrInfo(), MRI, *Ctx);
230   MCAsmBackend *MAB =
231       getTarget().createMCAsmBackend(STI, MRI, Options.MCOptions);
232   if (!MCE || !MAB)
233     return true;
234 
235   const Triple &T = getTargetTriple();
236   std::unique_ptr<MCStreamer> AsmStreamer(getTarget().createMCObjectStreamer(
237       T, *Ctx, std::unique_ptr<MCAsmBackend>(MAB), Out,
238       std::unique_ptr<MCCodeEmitter>(MCE), STI, Options.MCOptions.MCRelaxAll,
239       Options.MCOptions.MCIncrementalLinkerCompatible,
240       /*DWARFMustBeAtTheEnd*/ true));
241 
242   // Create the AsmPrinter, which takes ownership of AsmStreamer if successful.
243   FunctionPass *Printer =
244       getTarget().createAsmPrinter(*this, std::move(AsmStreamer));
245   if (!Printer)
246     return true;
247 
248   PM.add(Printer);
249   PM.add(createFreeMachineFunctionPass());
250 
251   return false; // success!
252 }
253