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 TargetIRAnalysis LLVMTargetMachine::getTargetIRAnalysis() {
85   return TargetIRAnalysis([this](const Function &F) {
86     return TargetTransformInfo(BasicTTIImpl(this, F));
87   });
88 }
89 
90 /// addPassesToX helper drives creation and initialization of TargetPassConfig.
91 static MCContext *
92 addPassesToGenerateCode(LLVMTargetMachine *TM, PassManagerBase &PM,
93                         bool DisableVerify, bool &WillCompleteCodeGenPipeline,
94                         raw_pwrite_stream &Out, MachineModuleInfo *MMI) {
95   // Targets may override createPassConfig to provide a target-specific
96   // subclass.
97   TargetPassConfig *PassConfig = TM->createPassConfig(PM);
98   // Set PassConfig options provided by TargetMachine.
99   PassConfig->setDisableVerify(DisableVerify);
100   WillCompleteCodeGenPipeline = PassConfig->willCompleteCodeGenPipeline();
101   PM.add(PassConfig);
102   if (!MMI)
103     MMI = new MachineModuleInfo(TM);
104   PM.add(MMI);
105 
106   if (PassConfig->addISelPasses())
107     return nullptr;
108   PassConfig->addMachinePasses();
109   PassConfig->setInitialized();
110   if (!WillCompleteCodeGenPipeline)
111     PM.add(createPrintMIRPass(Out));
112 
113   return &MMI->getContext();
114 }
115 
116 bool LLVMTargetMachine::addAsmPrinter(PassManagerBase &PM,
117     raw_pwrite_stream &Out, CodeGenFileType FileType,
118     MCContext &Context) {
119   if (Options.MCOptions.MCSaveTempLabels)
120     Context.setAllowTemporaryLabels(false);
121 
122   const MCSubtargetInfo &STI = *getMCSubtargetInfo();
123   const MCAsmInfo &MAI = *getMCAsmInfo();
124   const MCRegisterInfo &MRI = *getMCRegisterInfo();
125   const MCInstrInfo &MII = *getMCInstrInfo();
126 
127   std::unique_ptr<MCStreamer> AsmStreamer;
128 
129   switch (FileType) {
130   case CGFT_AssemblyFile: {
131     MCInstPrinter *InstPrinter = getTarget().createMCInstPrinter(
132         getTargetTriple(), MAI.getAssemblerDialect(), MAI, MII, MRI);
133 
134     // Create a code emitter if asked to show the encoding.
135     MCCodeEmitter *MCE = nullptr;
136     if (Options.MCOptions.ShowMCEncoding)
137       MCE = getTarget().createMCCodeEmitter(MII, MRI, Context);
138 
139     MCAsmBackend *MAB =
140         getTarget().createMCAsmBackend(MRI, getTargetTriple().str(), TargetCPU,
141                                        Options.MCOptions);
142     auto FOut = llvm::make_unique<formatted_raw_ostream>(Out);
143     MCStreamer *S = getTarget().createAsmStreamer(
144         Context, std::move(FOut), Options.MCOptions.AsmVerbose,
145         Options.MCOptions.MCUseDwarfDirectory, InstPrinter, MCE, MAB,
146         Options.MCOptions.ShowMCInst);
147     AsmStreamer.reset(S);
148     break;
149   }
150   case CGFT_ObjectFile: {
151     // Create the code emitter for the target if it exists.  If not, .o file
152     // emission fails.
153     MCCodeEmitter *MCE = getTarget().createMCCodeEmitter(MII, MRI, Context);
154     MCAsmBackend *MAB =
155         getTarget().createMCAsmBackend(MRI, getTargetTriple().str(), TargetCPU,
156                                        Options.MCOptions);
157     if (!MCE || !MAB)
158       return true;
159 
160     // Don't waste memory on names of temp labels.
161     Context.setUseNamesOnTempLabels(false);
162 
163     Triple T(getTargetTriple().str());
164     AsmStreamer.reset(getTarget().createMCObjectStreamer(
165         T, Context, std::unique_ptr<MCAsmBackend>(MAB), Out,
166         std::unique_ptr<MCCodeEmitter>(MCE), STI, Options.MCOptions.MCRelaxAll,
167         Options.MCOptions.MCIncrementalLinkerCompatible,
168         /*DWARFMustBeAtTheEnd*/ true));
169     break;
170   }
171   case CGFT_Null:
172     // The Null output is intended for use for performance analysis and testing,
173     // not real users.
174     AsmStreamer.reset(getTarget().createNullStreamer(Context));
175     break;
176   }
177 
178   // Create the AsmPrinter, which takes ownership of AsmStreamer if successful.
179   FunctionPass *Printer =
180       getTarget().createAsmPrinter(*this, std::move(AsmStreamer));
181   if (!Printer)
182     return true;
183 
184   PM.add(Printer);
185   return false;
186 }
187 
188 bool LLVMTargetMachine::addPassesToEmitFile(PassManagerBase &PM,
189                                             raw_pwrite_stream &Out,
190                                             CodeGenFileType FileType,
191                                             bool DisableVerify,
192                                             MachineModuleInfo *MMI) {
193   // Add common CodeGen passes.
194   bool WillCompleteCodeGenPipeline = true;
195   MCContext *Context = addPassesToGenerateCode(
196       this, PM, DisableVerify, WillCompleteCodeGenPipeline, Out, MMI);
197   if (!Context)
198     return true;
199 
200   if (WillCompleteCodeGenPipeline && addAsmPrinter(PM, Out, FileType, *Context))
201     return true;
202 
203   PM.add(createFreeMachineFunctionPass());
204   return false;
205 }
206 
207 /// addPassesToEmitMC - Add passes to the specified pass manager to get
208 /// machine code emitted with the MCJIT. This method returns true if machine
209 /// code is not supported. It fills the MCContext Ctx pointer which can be
210 /// used to build custom MCStreamer.
211 ///
212 bool LLVMTargetMachine::addPassesToEmitMC(PassManagerBase &PM, MCContext *&Ctx,
213                                           raw_pwrite_stream &Out,
214                                           bool DisableVerify) {
215   // Add common CodeGen passes.
216   bool WillCompleteCodeGenPipeline = true;
217   Ctx = addPassesToGenerateCode(this, PM, DisableVerify,
218                                 WillCompleteCodeGenPipeline, Out,
219                                 /*MachineModuleInfo*/ nullptr);
220   if (!Ctx)
221     return true;
222   assert(WillCompleteCodeGenPipeline && "CodeGen pipeline has been altered");
223 
224   if (Options.MCOptions.MCSaveTempLabels)
225     Ctx->setAllowTemporaryLabels(false);
226 
227   // Create the code emitter for the target if it exists.  If not, .o file
228   // emission fails.
229   const MCRegisterInfo &MRI = *getMCRegisterInfo();
230   MCCodeEmitter *MCE =
231       getTarget().createMCCodeEmitter(*getMCInstrInfo(), MRI, *Ctx);
232   MCAsmBackend *MAB =
233       getTarget().createMCAsmBackend(MRI, getTargetTriple().str(), TargetCPU,
234                                      Options.MCOptions);
235   if (!MCE || !MAB)
236     return true;
237 
238   const Triple &T = getTargetTriple();
239   const MCSubtargetInfo &STI = *getMCSubtargetInfo();
240   std::unique_ptr<MCStreamer> AsmStreamer(getTarget().createMCObjectStreamer(
241       T, *Ctx, std::unique_ptr<MCAsmBackend>(MAB), Out,
242       std::unique_ptr<MCCodeEmitter>(MCE), STI, Options.MCOptions.MCRelaxAll,
243       Options.MCOptions.MCIncrementalLinkerCompatible,
244       /*DWARFMustBeAtTheEnd*/ true));
245 
246   // Create the AsmPrinter, which takes ownership of AsmStreamer if successful.
247   FunctionPass *Printer =
248       getTarget().createAsmPrinter(*this, std::move(AsmStreamer));
249   if (!Printer)
250     return true;
251 
252   PM.add(Printer);
253   PM.add(createFreeMachineFunctionPass());
254 
255   return false; // success!
256 }
257