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/MCAsmBackend.h"
24 #include "llvm/MC/MCAsmInfo.h"
25 #include "llvm/MC/MCCodeEmitter.h"
26 #include "llvm/MC/MCContext.h"
27 #include "llvm/MC/MCInstrInfo.h"
28 #include "llvm/MC/MCStreamer.h"
29 #include "llvm/MC/MCSubtargetInfo.h"
30 #include "llvm/Support/CommandLine.h"
31 #include "llvm/Support/ErrorHandling.h"
32 #include "llvm/Support/FormattedStream.h"
33 #include "llvm/Support/TargetRegistry.h"
34 #include "llvm/Target/TargetLoweringObjectFile.h"
35 #include "llvm/Target/TargetMachine.h"
36 #include "llvm/Target/TargetOptions.h"
37 #include "llvm/Transforms/Scalar.h"
38 using namespace llvm;
39 
40 void LLVMTargetMachine::initAsmInfo() {
41   MRI = TheTarget.createMCRegInfo(getTargetTriple().str());
42   MII = TheTarget.createMCInstrInfo();
43   // FIXME: Having an MCSubtargetInfo on the target machine is a hack due
44   // to some backends having subtarget feature dependent module level
45   // code generation. This is similar to the hack in the AsmPrinter for
46   // module level assembly etc.
47   STI = TheTarget.createMCSubtargetInfo(getTargetTriple().str(), getTargetCPU(),
48                                         getTargetFeatureString());
49 
50   MCAsmInfo *TmpAsmInfo =
51       TheTarget.createMCAsmInfo(*MRI, getTargetTriple().str());
52   // TargetSelect.h moved to a different directory between LLVM 2.9 and 3.0,
53   // and if the old one gets included then MCAsmInfo will be NULL and
54   // we'll crash later.
55   // Provide the user with a useful error message about what's wrong.
56   assert(TmpAsmInfo && "MCAsmInfo not initialized. "
57          "Make sure you include the correct TargetSelect.h"
58          "and that InitializeAllTargetMCs() is being invoked!");
59 
60   if (Options.DisableIntegratedAS)
61     TmpAsmInfo->setUseIntegratedAssembler(false);
62 
63   TmpAsmInfo->setPreserveAsmComments(Options.MCOptions.PreserveAsmComments);
64 
65   TmpAsmInfo->setCompressDebugSections(Options.CompressDebugSections);
66 
67   TmpAsmInfo->setRelaxELFRelocations(Options.RelaxELFRelocations);
68 
69   if (Options.ExceptionModel != ExceptionHandling::None)
70     TmpAsmInfo->setExceptionsType(Options.ExceptionModel);
71 
72   AsmInfo = TmpAsmInfo;
73 }
74 
75 LLVMTargetMachine::LLVMTargetMachine(const Target &T,
76                                      StringRef DataLayoutString,
77                                      const Triple &TT, StringRef CPU,
78                                      StringRef FS, const TargetOptions &Options,
79                                      Reloc::Model RM, CodeModel::Model CM,
80                                      CodeGenOpt::Level OL)
81     : TargetMachine(T, DataLayoutString, TT, CPU, FS, Options) {
82   this->RM = RM;
83   this->CMModel = CM;
84   this->OptLevel = OL;
85 }
86 
87 TargetIRAnalysis LLVMTargetMachine::getTargetIRAnalysis() {
88   return TargetIRAnalysis([this](const Function &F) {
89     return TargetTransformInfo(BasicTTIImpl(this, F));
90   });
91 }
92 
93 /// addPassesToX helper drives creation and initialization of TargetPassConfig.
94 static MCContext *
95 addPassesToGenerateCode(LLVMTargetMachine *TM, PassManagerBase &PM,
96                         bool DisableVerify, bool &WillCompleteCodeGenPipeline,
97                         raw_pwrite_stream &Out, MachineModuleInfo *MMI) {
98   // Targets may override createPassConfig to provide a target-specific
99   // subclass.
100   TargetPassConfig *PassConfig = TM->createPassConfig(PM);
101   // Set PassConfig options provided by TargetMachine.
102   PassConfig->setDisableVerify(DisableVerify);
103   WillCompleteCodeGenPipeline = PassConfig->willCompleteCodeGenPipeline();
104   PM.add(PassConfig);
105   if (!MMI)
106     MMI = new MachineModuleInfo(TM);
107   PM.add(MMI);
108 
109   if (PassConfig->addISelPasses())
110     return nullptr;
111   PassConfig->addMachinePasses();
112   PassConfig->setInitialized();
113   if (!WillCompleteCodeGenPipeline)
114     PM.add(createPrintMIRPass(Out));
115 
116   return &MMI->getContext();
117 }
118 
119 bool LLVMTargetMachine::addAsmPrinter(PassManagerBase &PM,
120     raw_pwrite_stream &Out, CodeGenFileType FileType,
121     MCContext &Context) {
122   if (Options.MCOptions.MCSaveTempLabels)
123     Context.setAllowTemporaryLabels(false);
124 
125   const MCSubtargetInfo &STI = *getMCSubtargetInfo();
126   const MCAsmInfo &MAI = *getMCAsmInfo();
127   const MCRegisterInfo &MRI = *getMCRegisterInfo();
128   const MCInstrInfo &MII = *getMCInstrInfo();
129 
130   std::unique_ptr<MCStreamer> AsmStreamer;
131 
132   switch (FileType) {
133   case CGFT_AssemblyFile: {
134     MCInstPrinter *InstPrinter = getTarget().createMCInstPrinter(
135         getTargetTriple(), MAI.getAssemblerDialect(), MAI, MII, MRI);
136 
137     // Create a code emitter if asked to show the encoding.
138     MCCodeEmitter *MCE = nullptr;
139     if (Options.MCOptions.ShowMCEncoding)
140       MCE = getTarget().createMCCodeEmitter(MII, MRI, Context);
141 
142     MCAsmBackend *MAB =
143         getTarget().createMCAsmBackend(MRI, getTargetTriple().str(), TargetCPU,
144                                        Options.MCOptions);
145     auto FOut = llvm::make_unique<formatted_raw_ostream>(Out);
146     MCStreamer *S = getTarget().createAsmStreamer(
147         Context, std::move(FOut), Options.MCOptions.AsmVerbose,
148         Options.MCOptions.MCUseDwarfDirectory, InstPrinter, MCE, MAB,
149         Options.MCOptions.ShowMCInst);
150     AsmStreamer.reset(S);
151     break;
152   }
153   case CGFT_ObjectFile: {
154     // Create the code emitter for the target if it exists.  If not, .o file
155     // emission fails.
156     MCCodeEmitter *MCE = getTarget().createMCCodeEmitter(MII, MRI, Context);
157     MCAsmBackend *MAB =
158         getTarget().createMCAsmBackend(MRI, getTargetTriple().str(), TargetCPU,
159                                        Options.MCOptions);
160     if (!MCE || !MAB)
161       return true;
162 
163     // Don't waste memory on names of temp labels.
164     Context.setUseNamesOnTempLabels(false);
165 
166     Triple T(getTargetTriple().str());
167     AsmStreamer.reset(getTarget().createMCObjectStreamer(
168         T, Context, std::unique_ptr<MCAsmBackend>(MAB), Out,
169         std::unique_ptr<MCCodeEmitter>(MCE), STI, Options.MCOptions.MCRelaxAll,
170         Options.MCOptions.MCIncrementalLinkerCompatible,
171         /*DWARFMustBeAtTheEnd*/ true));
172     break;
173   }
174   case CGFT_Null:
175     // The Null output is intended for use for performance analysis and testing,
176     // not real users.
177     AsmStreamer.reset(getTarget().createNullStreamer(Context));
178     break;
179   }
180 
181   // Create the AsmPrinter, which takes ownership of AsmStreamer if successful.
182   FunctionPass *Printer =
183       getTarget().createAsmPrinter(*this, std::move(AsmStreamer));
184   if (!Printer)
185     return true;
186 
187   PM.add(Printer);
188   return false;
189 }
190 
191 bool LLVMTargetMachine::addPassesToEmitFile(PassManagerBase &PM,
192                                             raw_pwrite_stream &Out,
193                                             CodeGenFileType FileType,
194                                             bool DisableVerify,
195                                             MachineModuleInfo *MMI) {
196   // Add common CodeGen passes.
197   bool WillCompleteCodeGenPipeline = true;
198   MCContext *Context = addPassesToGenerateCode(
199       this, PM, DisableVerify, WillCompleteCodeGenPipeline, Out, MMI);
200   if (!Context)
201     return true;
202 
203   if (WillCompleteCodeGenPipeline && addAsmPrinter(PM, Out, FileType, *Context))
204     return true;
205 
206   PM.add(createFreeMachineFunctionPass());
207   return false;
208 }
209 
210 /// addPassesToEmitMC - Add passes to the specified pass manager to get
211 /// machine code emitted with the MCJIT. This method returns true if machine
212 /// code is not supported. It fills the MCContext Ctx pointer which can be
213 /// used to build custom MCStreamer.
214 ///
215 bool LLVMTargetMachine::addPassesToEmitMC(PassManagerBase &PM, MCContext *&Ctx,
216                                           raw_pwrite_stream &Out,
217                                           bool DisableVerify) {
218   // Add common CodeGen passes.
219   bool WillCompleteCodeGenPipeline = true;
220   Ctx = addPassesToGenerateCode(this, PM, DisableVerify,
221                                 WillCompleteCodeGenPipeline, Out,
222                                 /*MachineModuleInfo*/ nullptr);
223   if (!Ctx)
224     return true;
225   assert(WillCompleteCodeGenPipeline && "CodeGen pipeline has been altered");
226 
227   if (Options.MCOptions.MCSaveTempLabels)
228     Ctx->setAllowTemporaryLabels(false);
229 
230   // Create the code emitter for the target if it exists.  If not, .o file
231   // emission fails.
232   const MCRegisterInfo &MRI = *getMCRegisterInfo();
233   MCCodeEmitter *MCE =
234       getTarget().createMCCodeEmitter(*getMCInstrInfo(), MRI, *Ctx);
235   MCAsmBackend *MAB =
236       getTarget().createMCAsmBackend(MRI, getTargetTriple().str(), TargetCPU,
237                                      Options.MCOptions);
238   if (!MCE || !MAB)
239     return true;
240 
241   const Triple &T = getTargetTriple();
242   const MCSubtargetInfo &STI = *getMCSubtargetInfo();
243   std::unique_ptr<MCStreamer> AsmStreamer(getTarget().createMCObjectStreamer(
244       T, *Ctx, std::unique_ptr<MCAsmBackend>(MAB), Out,
245       std::unique_ptr<MCCodeEmitter>(MCE), STI, Options.MCOptions.MCRelaxAll,
246       Options.MCOptions.MCIncrementalLinkerCompatible,
247       /*DWARFMustBeAtTheEnd*/ true));
248 
249   // Create the AsmPrinter, which takes ownership of AsmStreamer if successful.
250   FunctionPass *Printer =
251       getTarget().createAsmPrinter(*this, std::move(AsmStreamer));
252   if (!Printer)
253     return true;
254 
255   PM.add(Printer);
256   PM.add(createFreeMachineFunctionPass());
257 
258   return false; // success!
259 }
260