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/LegacyPassManager.h"
21 #include "llvm/MC/MCAsmBackend.h"
22 #include "llvm/MC/MCAsmInfo.h"
23 #include "llvm/MC/MCCodeEmitter.h"
24 #include "llvm/MC/MCContext.h"
25 #include "llvm/MC/MCInstrInfo.h"
26 #include "llvm/MC/MCObjectWriter.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/TargetLoweringObjectFile.h"
34 #include "llvm/Target/TargetMachine.h"
35 #include "llvm/Target/TargetOptions.h"
36 using namespace llvm;
37 
38 static cl::opt<bool> EnableTrapUnreachable("trap-unreachable",
39   cl::Hidden, cl::ZeroOrMore, cl::init(false),
40   cl::desc("Enable generating trap for unreachable"));
41 
42 void LLVMTargetMachine::initAsmInfo() {
43   MRI.reset(TheTarget.createMCRegInfo(getTargetTriple().str()));
44   MII.reset(TheTarget.createMCInstrInfo());
45   // FIXME: Having an MCSubtargetInfo on the target machine is a hack due
46   // to some backends having subtarget feature dependent module level
47   // code generation. This is similar to the hack in the AsmPrinter for
48   // module level assembly etc.
49   STI.reset(TheTarget.createMCSubtargetInfo(
50       getTargetTriple().str(), getTargetCPU(), getTargetFeatureString()));
51 
52   MCAsmInfo *TmpAsmInfo =
53       TheTarget.createMCAsmInfo(*MRI, getTargetTriple().str());
54   // TargetSelect.h moved to a different directory between LLVM 2.9 and 3.0,
55   // and if the old one gets included then MCAsmInfo will be NULL and
56   // we'll crash later.
57   // Provide the user with a useful error message about what's wrong.
58   assert(TmpAsmInfo && "MCAsmInfo not initialized. "
59          "Make sure you include the correct TargetSelect.h"
60          "and that InitializeAllTargetMCs() is being invoked!");
61 
62   if (Options.DisableIntegratedAS)
63     TmpAsmInfo->setUseIntegratedAssembler(false);
64 
65   TmpAsmInfo->setPreserveAsmComments(Options.MCOptions.PreserveAsmComments);
66 
67   TmpAsmInfo->setCompressDebugSections(Options.CompressDebugSections);
68 
69   TmpAsmInfo->setRelaxELFRelocations(Options.RelaxELFRelocations);
70 
71   if (Options.ExceptionModel != ExceptionHandling::None)
72     TmpAsmInfo->setExceptionsType(Options.ExceptionModel);
73 
74   AsmInfo.reset(TmpAsmInfo);
75 }
76 
77 LLVMTargetMachine::LLVMTargetMachine(const Target &T,
78                                      StringRef DataLayoutString,
79                                      const Triple &TT, StringRef CPU,
80                                      StringRef FS, const TargetOptions &Options,
81                                      Reloc::Model RM, CodeModel::Model CM,
82                                      CodeGenOpt::Level OL)
83     : TargetMachine(T, DataLayoutString, TT, CPU, FS, Options) {
84   this->RM = RM;
85   this->CMModel = CM;
86   this->OptLevel = OL;
87 
88   if (EnableTrapUnreachable)
89     this->Options.TrapUnreachable = true;
90 }
91 
92 TargetTransformInfo
93 LLVMTargetMachine::getTargetTransformInfo(const Function &F) {
94   return TargetTransformInfo(BasicTTIImpl(this, F));
95 }
96 
97 /// addPassesToX helper drives creation and initialization of TargetPassConfig.
98 static TargetPassConfig *
99 addPassesToGenerateCode(LLVMTargetMachine &TM, PassManagerBase &PM,
100                         bool DisableVerify, MachineModuleInfo &MMI) {
101   // Targets may override createPassConfig to provide a target-specific
102   // subclass.
103   TargetPassConfig *PassConfig = TM.createPassConfig(PM);
104   // Set PassConfig options provided by TargetMachine.
105   PassConfig->setDisableVerify(DisableVerify);
106   PM.add(PassConfig);
107   PM.add(&MMI);
108 
109   if (PassConfig->addISelPasses())
110     return nullptr;
111   PassConfig->addMachinePasses();
112   PassConfig->setInitialized();
113   return PassConfig;
114 }
115 
116 bool LLVMTargetMachine::addAsmPrinter(PassManagerBase &PM,
117                                       raw_pwrite_stream &Out,
118                                       raw_pwrite_stream *DwoOut,
119                                       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     std::unique_ptr<MCCodeEmitter> MCE;
138     if (Options.MCOptions.ShowMCEncoding)
139       MCE.reset(getTarget().createMCCodeEmitter(MII, MRI, Context));
140 
141     std::unique_ptr<MCAsmBackend> MAB(
142         getTarget().createMCAsmBackend(STI, MRI, 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, std::move(MCE),
147         std::move(MAB), 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(STI, MRI, 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),
166         DwoOut ? MAB->createDwoObjectWriter(Out, *DwoOut)
167                : MAB->createObjectWriter(Out),
168         std::unique_ptr<MCCodeEmitter>(MCE), STI, Options.MCOptions.MCRelaxAll,
169         Options.MCOptions.MCIncrementalLinkerCompatible,
170         /*DWARFMustBeAtTheEnd*/ true));
171     break;
172   }
173   case CGFT_Null:
174     // The Null output is intended for use for performance analysis and testing,
175     // not real users.
176     AsmStreamer.reset(getTarget().createNullStreamer(Context));
177     break;
178   }
179 
180   // Create the AsmPrinter, which takes ownership of AsmStreamer if successful.
181   FunctionPass *Printer =
182       getTarget().createAsmPrinter(*this, std::move(AsmStreamer));
183   if (!Printer)
184     return true;
185 
186   PM.add(Printer);
187   return false;
188 }
189 
190 bool LLVMTargetMachine::addPassesToEmitFile(PassManagerBase &PM,
191                                             raw_pwrite_stream &Out,
192                                             raw_pwrite_stream *DwoOut,
193                                             CodeGenFileType FileType,
194                                             bool DisableVerify,
195                                             MachineModuleInfo *MMI) {
196   // Add common CodeGen passes.
197   if (!MMI)
198     MMI = new MachineModuleInfo(this);
199   TargetPassConfig *PassConfig =
200       addPassesToGenerateCode(*this, PM, DisableVerify, *MMI);
201   if (!PassConfig)
202     return true;
203 
204   if (!TargetPassConfig::willCompleteCodeGenPipeline()) {
205     PM.add(createPrintMIRPass(Out));
206   } else if (addAsmPrinter(PM, Out, DwoOut, FileType, MMI->getContext()))
207     return true;
208 
209   PM.add(createFreeMachineFunctionPass());
210   return false;
211 }
212 
213 /// addPassesToEmitMC - Add passes to the specified pass manager to get
214 /// machine code emitted with the MCJIT. This method returns true if machine
215 /// code is not supported. It fills the MCContext Ctx pointer which can be
216 /// used to build custom MCStreamer.
217 ///
218 bool LLVMTargetMachine::addPassesToEmitMC(PassManagerBase &PM, MCContext *&Ctx,
219                                           raw_pwrite_stream &Out,
220                                           bool DisableVerify) {
221   // Add common CodeGen passes.
222   MachineModuleInfo *MMI = new MachineModuleInfo(this);
223   TargetPassConfig *PassConfig =
224       addPassesToGenerateCode(*this, PM, DisableVerify, *MMI);
225   if (!PassConfig)
226     return true;
227   assert(TargetPassConfig::willCompleteCodeGenPipeline() &&
228          "Cannot emit MC with limited codegen pipeline");
229 
230   Ctx = &MMI->getContext();
231   if (Options.MCOptions.MCSaveTempLabels)
232     Ctx->setAllowTemporaryLabels(false);
233 
234   // Create the code emitter for the target if it exists.  If not, .o file
235   // emission fails.
236   const MCSubtargetInfo &STI = *getMCSubtargetInfo();
237   const MCRegisterInfo &MRI = *getMCRegisterInfo();
238   MCCodeEmitter *MCE =
239       getTarget().createMCCodeEmitter(*getMCInstrInfo(), MRI, *Ctx);
240   MCAsmBackend *MAB =
241       getTarget().createMCAsmBackend(STI, MRI, Options.MCOptions);
242   if (!MCE || !MAB)
243     return true;
244 
245   const Triple &T = getTargetTriple();
246   std::unique_ptr<MCStreamer> AsmStreamer(getTarget().createMCObjectStreamer(
247       T, *Ctx, std::unique_ptr<MCAsmBackend>(MAB), MAB->createObjectWriter(Out),
248       std::unique_ptr<MCCodeEmitter>(MCE), STI, Options.MCOptions.MCRelaxAll,
249       Options.MCOptions.MCIncrementalLinkerCompatible,
250       /*DWARFMustBeAtTheEnd*/ true));
251 
252   // Create the AsmPrinter, which takes ownership of AsmStreamer if successful.
253   FunctionPass *Printer =
254       getTarget().createAsmPrinter(*this, std::move(AsmStreamer));
255   if (!Printer)
256     return true;
257 
258   PM.add(Printer);
259   PM.add(createFreeMachineFunctionPass());
260 
261   return false; // success!
262 }
263