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/TargetPassConfig.h"
20 #include "llvm/IR/IRPrintingPasses.h"
21 #include "llvm/IR/LegacyPassManager.h"
22 #include "llvm/IR/Verifier.h"
23 #include "llvm/MC/MCAsmInfo.h"
24 #include "llvm/MC/MCContext.h"
25 #include "llvm/MC/MCInstrInfo.h"
26 #include "llvm/MC/MCStreamer.h"
27 #include "llvm/MC/MCSubtargetInfo.h"
28 #include "llvm/Support/CommandLine.h"
29 #include "llvm/Support/ErrorHandling.h"
30 #include "llvm/Support/FormattedStream.h"
31 #include "llvm/Support/TargetRegistry.h"
32 #include "llvm/Target/TargetLoweringObjectFile.h"
33 #include "llvm/Target/TargetMachine.h"
34 #include "llvm/Target/TargetOptions.h"
35 #include "llvm/Transforms/Scalar.h"
36 using namespace llvm;
37 
38 void LLVMTargetMachine::initAsmInfo() {
39   MRI = TheTarget.createMCRegInfo(getTargetTriple().str());
40   MII = TheTarget.createMCInstrInfo();
41   // FIXME: Having an MCSubtargetInfo on the target machine is a hack due
42   // to some backends having subtarget feature dependent module level
43   // code generation. This is similar to the hack in the AsmPrinter for
44   // module level assembly etc.
45   STI = TheTarget.createMCSubtargetInfo(getTargetTriple().str(), getTargetCPU(),
46                                         getTargetFeatureString());
47 
48   MCAsmInfo *TmpAsmInfo =
49       TheTarget.createMCAsmInfo(*MRI, getTargetTriple().str());
50   // TargetSelect.h moved to a different directory between LLVM 2.9 and 3.0,
51   // and if the old one gets included then MCAsmInfo will be NULL and
52   // we'll crash later.
53   // Provide the user with a useful error message about what's wrong.
54   assert(TmpAsmInfo && "MCAsmInfo not initialized. "
55          "Make sure you include the correct TargetSelect.h"
56          "and that InitializeAllTargetMCs() is being invoked!");
57 
58   if (Options.DisableIntegratedAS)
59     TmpAsmInfo->setUseIntegratedAssembler(false);
60 
61   TmpAsmInfo->setPreserveAsmComments(Options.MCOptions.PreserveAsmComments);
62 
63   TmpAsmInfo->setCompressDebugSections(Options.CompressDebugSections);
64 
65   TmpAsmInfo->setRelaxELFRelocations(Options.RelaxELFRelocations);
66 
67   if (Options.ExceptionModel != ExceptionHandling::None)
68     TmpAsmInfo->setExceptionsType(Options.ExceptionModel);
69 
70   AsmInfo = TmpAsmInfo;
71 }
72 
73 LLVMTargetMachine::LLVMTargetMachine(const Target &T,
74                                      StringRef DataLayoutString,
75                                      const Triple &TT, StringRef CPU,
76                                      StringRef FS, const TargetOptions &Options,
77                                      Reloc::Model RM, CodeModel::Model CM,
78                                      CodeGenOpt::Level OL)
79     : TargetMachine(T, DataLayoutString, TT, CPU, FS, Options) {
80   this->RM = RM;
81   this->CMModel = CM;
82   this->OptLevel = OL;
83 }
84 
85 TargetIRAnalysis LLVMTargetMachine::getTargetIRAnalysis() {
86   return TargetIRAnalysis([this](const Function &F) {
87     return TargetTransformInfo(BasicTTIImpl(this, F));
88   });
89 }
90 
91 /// addPassesToX helper drives creation and initialization of TargetPassConfig.
92 static MCContext *
93 addPassesToGenerateCode(LLVMTargetMachine *TM, PassManagerBase &PM,
94                         bool DisableVerify, bool &WillCompleteCodeGenPipeline,
95                         raw_pwrite_stream &Out, MachineModuleInfo *MMI) {
96   // Targets may override createPassConfig to provide a target-specific
97   // subclass.
98   TargetPassConfig *PassConfig = TM->createPassConfig(PM);
99   // Set PassConfig options provided by TargetMachine.
100   PassConfig->setDisableVerify(DisableVerify);
101   WillCompleteCodeGenPipeline = PassConfig->willCompleteCodeGenPipeline();
102   PM.add(PassConfig);
103   if (!MMI)
104     MMI = new MachineModuleInfo(TM);
105   PM.add(MMI);
106 
107   if (PassConfig->addISelPasses())
108     return nullptr;
109   PassConfig->addMachinePasses();
110   PassConfig->setInitialized();
111   if (!WillCompleteCodeGenPipeline)
112     PM.add(createPrintMIRPass(Out));
113 
114   return &MMI->getContext();
115 }
116 
117 bool LLVMTargetMachine::addAsmPrinter(PassManagerBase &PM,
118     raw_pwrite_stream &Out, CodeGenFileType FileType,
119     MCContext &Context) {
120   if (Options.MCOptions.MCSaveTempLabels)
121     Context.setAllowTemporaryLabels(false);
122 
123   const MCSubtargetInfo &STI = *getMCSubtargetInfo();
124   const MCAsmInfo &MAI = *getMCAsmInfo();
125   const MCRegisterInfo &MRI = *getMCRegisterInfo();
126   const MCInstrInfo &MII = *getMCInstrInfo();
127 
128   std::unique_ptr<MCStreamer> AsmStreamer;
129 
130   switch (FileType) {
131   case CGFT_AssemblyFile: {
132     MCInstPrinter *InstPrinter = getTarget().createMCInstPrinter(
133         getTargetTriple(), MAI.getAssemblerDialect(), MAI, MII, MRI);
134 
135     // Create a code emitter if asked to show the encoding.
136     MCCodeEmitter *MCE = nullptr;
137     if (Options.MCOptions.ShowMCEncoding)
138       MCE = getTarget().createMCCodeEmitter(MII, MRI, Context);
139 
140     MCAsmBackend *MAB =
141         getTarget().createMCAsmBackend(MRI, getTargetTriple().str(), TargetCPU,
142                                        Options.MCOptions);
143     auto FOut = llvm::make_unique<formatted_raw_ostream>(Out);
144     MCStreamer *S = getTarget().createAsmStreamer(
145         Context, std::move(FOut), Options.MCOptions.AsmVerbose,
146         Options.MCOptions.MCUseDwarfDirectory, InstPrinter, MCE, MAB,
147         Options.MCOptions.ShowMCInst);
148     AsmStreamer.reset(S);
149     break;
150   }
151   case CGFT_ObjectFile: {
152     // Create the code emitter for the target if it exists.  If not, .o file
153     // emission fails.
154     MCCodeEmitter *MCE = getTarget().createMCCodeEmitter(MII, MRI, Context);
155     MCAsmBackend *MAB =
156         getTarget().createMCAsmBackend(MRI, getTargetTriple().str(), TargetCPU,
157                                        Options.MCOptions);
158     if (!MCE || !MAB)
159       return true;
160 
161     // Don't waste memory on names of temp labels.
162     Context.setUseNamesOnTempLabels(false);
163 
164     Triple T(getTargetTriple().str());
165     AsmStreamer.reset(getTarget().createMCObjectStreamer(
166         T, Context, *MAB, Out, 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, *MAB, Out, 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