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(MRI, getTargetTriple().str(), TargetCPU,
140                                        Options.MCOptions);
141     auto FOut = llvm::make_unique<formatted_raw_ostream>(Out);
142     MCStreamer *S = getTarget().createAsmStreamer(
143         Context, std::move(FOut), Options.MCOptions.AsmVerbose,
144         Options.MCOptions.MCUseDwarfDirectory, InstPrinter, MCE, MAB,
145         Options.MCOptions.ShowMCInst);
146     AsmStreamer.reset(S);
147     break;
148   }
149   case CGFT_ObjectFile: {
150     // Create the code emitter for the target if it exists.  If not, .o file
151     // emission fails.
152     MCCodeEmitter *MCE = getTarget().createMCCodeEmitter(MII, MRI, Context);
153     MCAsmBackend *MAB =
154         getTarget().createMCAsmBackend(MRI, getTargetTriple().str(), TargetCPU,
155                                        Options.MCOptions);
156     if (!MCE || !MAB)
157       return true;
158 
159     // Don't waste memory on names of temp labels.
160     Context.setUseNamesOnTempLabels(false);
161 
162     Triple T(getTargetTriple().str());
163     AsmStreamer.reset(getTarget().createMCObjectStreamer(
164         T, Context, std::unique_ptr<MCAsmBackend>(MAB), Out,
165         std::unique_ptr<MCCodeEmitter>(MCE), STI, Options.MCOptions.MCRelaxAll,
166         Options.MCOptions.MCIncrementalLinkerCompatible,
167         /*DWARFMustBeAtTheEnd*/ true));
168     break;
169   }
170   case CGFT_Null:
171     // The Null output is intended for use for performance analysis and testing,
172     // not real users.
173     AsmStreamer.reset(getTarget().createNullStreamer(Context));
174     break;
175   }
176 
177   // Create the AsmPrinter, which takes ownership of AsmStreamer if successful.
178   FunctionPass *Printer =
179       getTarget().createAsmPrinter(*this, std::move(AsmStreamer));
180   if (!Printer)
181     return true;
182 
183   PM.add(Printer);
184   return false;
185 }
186 
187 bool LLVMTargetMachine::addPassesToEmitFile(PassManagerBase &PM,
188                                             raw_pwrite_stream &Out,
189                                             CodeGenFileType FileType,
190                                             bool DisableVerify,
191                                             MachineModuleInfo *MMI) {
192   // Add common CodeGen passes.
193   bool WillCompleteCodeGenPipeline = true;
194   MCContext *Context = addPassesToGenerateCode(
195       this, PM, DisableVerify, WillCompleteCodeGenPipeline, Out, MMI);
196   if (!Context)
197     return true;
198 
199   if (WillCompleteCodeGenPipeline && addAsmPrinter(PM, Out, FileType, *Context))
200     return true;
201 
202   PM.add(createFreeMachineFunctionPass());
203   return false;
204 }
205 
206 /// addPassesToEmitMC - Add passes to the specified pass manager to get
207 /// machine code emitted with the MCJIT. This method returns true if machine
208 /// code is not supported. It fills the MCContext Ctx pointer which can be
209 /// used to build custom MCStreamer.
210 ///
211 bool LLVMTargetMachine::addPassesToEmitMC(PassManagerBase &PM, MCContext *&Ctx,
212                                           raw_pwrite_stream &Out,
213                                           bool DisableVerify) {
214   // Add common CodeGen passes.
215   bool WillCompleteCodeGenPipeline = true;
216   Ctx = addPassesToGenerateCode(this, PM, DisableVerify,
217                                 WillCompleteCodeGenPipeline, Out,
218                                 /*MachineModuleInfo*/ nullptr);
219   if (!Ctx)
220     return true;
221   assert(WillCompleteCodeGenPipeline && "CodeGen pipeline has been altered");
222 
223   if (Options.MCOptions.MCSaveTempLabels)
224     Ctx->setAllowTemporaryLabels(false);
225 
226   // Create the code emitter for the target if it exists.  If not, .o file
227   // emission fails.
228   const MCRegisterInfo &MRI = *getMCRegisterInfo();
229   MCCodeEmitter *MCE =
230       getTarget().createMCCodeEmitter(*getMCInstrInfo(), MRI, *Ctx);
231   MCAsmBackend *MAB =
232       getTarget().createMCAsmBackend(MRI, getTargetTriple().str(), TargetCPU,
233                                      Options.MCOptions);
234   if (!MCE || !MAB)
235     return true;
236 
237   const Triple &T = getTargetTriple();
238   const MCSubtargetInfo &STI = *getMCSubtargetInfo();
239   std::unique_ptr<MCStreamer> AsmStreamer(getTarget().createMCObjectStreamer(
240       T, *Ctx, std::unique_ptr<MCAsmBackend>(MAB), Out,
241       std::unique_ptr<MCCodeEmitter>(MCE), STI, Options.MCOptions.MCRelaxAll,
242       Options.MCOptions.MCIncrementalLinkerCompatible,
243       /*DWARFMustBeAtTheEnd*/ true));
244 
245   // Create the AsmPrinter, which takes ownership of AsmStreamer if successful.
246   FunctionPass *Printer =
247       getTarget().createAsmPrinter(*this, std::move(AsmStreamer));
248   if (!Printer)
249     return true;
250 
251   PM.add(Printer);
252   PM.add(createFreeMachineFunctionPass());
253 
254   return false; // success!
255 }
256