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   if (Options.CompressDebugSections)
64     TmpAsmInfo->setCompressDebugSections(DebugCompressionType::DCT_ZlibGnu);
65 
66   TmpAsmInfo->setRelaxELFRelocations(Options.RelaxELFRelocations);
67 
68   if (Options.ExceptionModel != ExceptionHandling::None)
69     TmpAsmInfo->setExceptionsType(Options.ExceptionModel);
70 
71   AsmInfo = TmpAsmInfo;
72 }
73 
74 LLVMTargetMachine::LLVMTargetMachine(const Target &T,
75                                      StringRef DataLayoutString,
76                                      const Triple &TT, StringRef CPU,
77                                      StringRef FS, const TargetOptions &Options,
78                                      Reloc::Model RM, CodeModel::Model CM,
79                                      CodeGenOpt::Level OL)
80     : TargetMachine(T, DataLayoutString, TT, CPU, FS, Options) {
81   T.adjustCodeGenOpts(TT, RM, CM);
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, AnalysisID StartBefore,
97                         AnalysisID StartAfter, AnalysisID StopBefore,
98                         AnalysisID StopAfter) {
99   // Targets may override createPassConfig to provide a target-specific
100   // subclass.
101   TargetPassConfig *PassConfig = TM->createPassConfig(PM);
102   PassConfig->setStartStopPasses(StartBefore, StartAfter, StopBefore,
103                                  StopAfter);
104   // Set PassConfig options provided by TargetMachine.
105   PassConfig->setDisableVerify(DisableVerify);
106   PM.add(PassConfig);
107   MachineModuleInfo *MMI = new MachineModuleInfo(TM);
108   PM.add(MMI);
109 
110   if (PassConfig->addISelPasses())
111     return nullptr;
112   PassConfig->addMachinePasses();
113   PassConfig->setInitialized();
114 
115   return &MMI->getContext();
116 }
117 
118 bool LLVMTargetMachine::addAsmPrinter(PassManagerBase &PM,
119     raw_pwrite_stream &Out, CodeGenFileType FileType,
120     MCContext &Context) {
121   if (Options.MCOptions.MCSaveTempLabels)
122     Context.setAllowTemporaryLabels(false);
123 
124   const MCSubtargetInfo &STI = *getMCSubtargetInfo();
125   const MCAsmInfo &MAI = *getMCAsmInfo();
126   const MCRegisterInfo &MRI = *getMCRegisterInfo();
127   const MCInstrInfo &MII = *getMCInstrInfo();
128 
129   std::unique_ptr<MCStreamer> AsmStreamer;
130 
131   switch (FileType) {
132   case CGFT_AssemblyFile: {
133     MCInstPrinter *InstPrinter = getTarget().createMCInstPrinter(
134         getTargetTriple(), MAI.getAssemblerDialect(), MAI, MII, MRI);
135 
136     // Create a code emitter if asked to show the encoding.
137     MCCodeEmitter *MCE = nullptr;
138     if (Options.MCOptions.ShowMCEncoding)
139       MCE = getTarget().createMCCodeEmitter(MII, MRI, Context);
140 
141     MCAsmBackend *MAB =
142         getTarget().createMCAsmBackend(MRI, getTargetTriple().str(), TargetCPU,
143                                        Options.MCOptions);
144     auto FOut = llvm::make_unique<formatted_raw_ostream>(Out);
145     MCStreamer *S = getTarget().createAsmStreamer(
146         Context, std::move(FOut), Options.MCOptions.AsmVerbose,
147         Options.MCOptions.MCUseDwarfDirectory, InstPrinter, MCE, MAB,
148         Options.MCOptions.ShowMCInst);
149     AsmStreamer.reset(S);
150     break;
151   }
152   case CGFT_ObjectFile: {
153     // Create the code emitter for the target if it exists.  If not, .o file
154     // emission fails.
155     MCCodeEmitter *MCE = getTarget().createMCCodeEmitter(MII, MRI, Context);
156     MCAsmBackend *MAB =
157         getTarget().createMCAsmBackend(MRI, getTargetTriple().str(), TargetCPU,
158                                        Options.MCOptions);
159     if (!MCE || !MAB)
160       return true;
161 
162     // Don't waste memory on names of temp labels.
163     Context.setUseNamesOnTempLabels(false);
164 
165     Triple T(getTargetTriple().str());
166     AsmStreamer.reset(getTarget().createMCObjectStreamer(
167         T, Context, *MAB, Out, MCE, STI, Options.MCOptions.MCRelaxAll,
168         Options.MCOptions.MCIncrementalLinkerCompatible,
169         /*DWARFMustBeAtTheEnd*/ true));
170     break;
171   }
172   case CGFT_Null:
173     // The Null output is intended for use for performance analysis and testing,
174     // not real users.
175     AsmStreamer.reset(getTarget().createNullStreamer(Context));
176     break;
177   }
178 
179   // Create the AsmPrinter, which takes ownership of AsmStreamer if successful.
180   FunctionPass *Printer =
181       getTarget().createAsmPrinter(*this, std::move(AsmStreamer));
182   if (!Printer)
183     return true;
184 
185   PM.add(Printer);
186   return false;
187 }
188 
189 bool LLVMTargetMachine::addPassesToEmitFile(
190     PassManagerBase &PM, raw_pwrite_stream &Out, CodeGenFileType FileType,
191     bool DisableVerify, AnalysisID StartBefore, AnalysisID StartAfter,
192     AnalysisID StopBefore, AnalysisID StopAfter) {
193   // Add common CodeGen passes.
194   MCContext *Context =
195       addPassesToGenerateCode(this, PM, DisableVerify, StartBefore, StartAfter,
196                               StopBefore, StopAfter);
197   if (!Context)
198     return true;
199 
200   if (StopBefore || StopAfter) {
201     PM.add(createPrintMIRPass(Out));
202   } else {
203     if (addAsmPrinter(PM, Out, FileType, *Context))
204       return true;
205   }
206 
207   PM.add(createFreeMachineFunctionPass());
208   return false;
209 }
210 
211 /// addPassesToEmitMC - Add passes to the specified pass manager to get
212 /// machine code emitted with the MCJIT. This method returns true if machine
213 /// code is not supported. It fills the MCContext Ctx pointer which can be
214 /// used to build custom MCStreamer.
215 ///
216 bool LLVMTargetMachine::addPassesToEmitMC(PassManagerBase &PM, MCContext *&Ctx,
217                                           raw_pwrite_stream &Out,
218                                           bool DisableVerify) {
219   // Add common CodeGen passes.
220   Ctx = addPassesToGenerateCode(this, PM, DisableVerify, nullptr, nullptr,
221                                 nullptr, nullptr);
222   if (!Ctx)
223     return true;
224 
225   if (Options.MCOptions.MCSaveTempLabels)
226     Ctx->setAllowTemporaryLabels(false);
227 
228   // Create the code emitter for the target if it exists.  If not, .o file
229   // emission fails.
230   const MCRegisterInfo &MRI = *getMCRegisterInfo();
231   MCCodeEmitter *MCE =
232       getTarget().createMCCodeEmitter(*getMCInstrInfo(), MRI, *Ctx);
233   MCAsmBackend *MAB =
234       getTarget().createMCAsmBackend(MRI, getTargetTriple().str(), TargetCPU,
235                                      Options.MCOptions);
236   if (!MCE || !MAB)
237     return true;
238 
239   const Triple &T = getTargetTriple();
240   const MCSubtargetInfo &STI = *getMCSubtargetInfo();
241   std::unique_ptr<MCStreamer> AsmStreamer(getTarget().createMCObjectStreamer(
242       T, *Ctx, *MAB, Out, 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