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 = TheTarget.createMCRegInfo(getTargetTriple().str());
44   MII = 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 = TheTarget.createMCSubtargetInfo(getTargetTriple().str(), getTargetCPU(),
50                                         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 = 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 MCContext *
99 addPassesToGenerateCode(LLVMTargetMachine *TM, PassManagerBase &PM,
100                         bool DisableVerify, bool &WillCompleteCodeGenPipeline,
101                         raw_pwrite_stream &Out, MachineModuleInfo *MMI) {
102   // Targets may override createPassConfig to provide a target-specific
103   // subclass.
104   TargetPassConfig *PassConfig = TM->createPassConfig(PM);
105   // Set PassConfig options provided by TargetMachine.
106   PassConfig->setDisableVerify(DisableVerify);
107   WillCompleteCodeGenPipeline = PassConfig->willCompleteCodeGenPipeline();
108   PM.add(PassConfig);
109   if (!MMI)
110     MMI = new MachineModuleInfo(TM);
111   PM.add(MMI);
112 
113   if (PassConfig->addISelPasses())
114     return nullptr;
115   PassConfig->addMachinePasses();
116   PassConfig->setInitialized();
117   if (!WillCompleteCodeGenPipeline)
118     PM.add(createPrintMIRPass(Out));
119 
120   return &MMI->getContext();
121 }
122 
123 bool LLVMTargetMachine::addAsmPrinter(PassManagerBase &PM,
124                                       raw_pwrite_stream &Out,
125                                       raw_pwrite_stream *DwoOut,
126                                       CodeGenFileType FileType,
127                                       MCContext &Context) {
128   if (Options.MCOptions.MCSaveTempLabels)
129     Context.setAllowTemporaryLabels(false);
130 
131   const MCSubtargetInfo &STI = *getMCSubtargetInfo();
132   const MCAsmInfo &MAI = *getMCAsmInfo();
133   const MCRegisterInfo &MRI = *getMCRegisterInfo();
134   const MCInstrInfo &MII = *getMCInstrInfo();
135 
136   std::unique_ptr<MCStreamer> AsmStreamer;
137 
138   switch (FileType) {
139   case CGFT_AssemblyFile: {
140     MCInstPrinter *InstPrinter = getTarget().createMCInstPrinter(
141         getTargetTriple(), MAI.getAssemblerDialect(), MAI, MII, MRI);
142 
143     // Create a code emitter if asked to show the encoding.
144     std::unique_ptr<MCCodeEmitter> MCE;
145     if (Options.MCOptions.ShowMCEncoding)
146       MCE.reset(getTarget().createMCCodeEmitter(MII, MRI, Context));
147 
148     std::unique_ptr<MCAsmBackend> MAB(
149         getTarget().createMCAsmBackend(STI, MRI, Options.MCOptions));
150     auto FOut = llvm::make_unique<formatted_raw_ostream>(Out);
151     MCStreamer *S = getTarget().createAsmStreamer(
152         Context, std::move(FOut), Options.MCOptions.AsmVerbose,
153         Options.MCOptions.MCUseDwarfDirectory, InstPrinter, std::move(MCE),
154         std::move(MAB), Options.MCOptions.ShowMCInst);
155     AsmStreamer.reset(S);
156     break;
157   }
158   case CGFT_ObjectFile: {
159     // Create the code emitter for the target if it exists.  If not, .o file
160     // emission fails.
161     MCCodeEmitter *MCE = getTarget().createMCCodeEmitter(MII, MRI, Context);
162     MCAsmBackend *MAB =
163         getTarget().createMCAsmBackend(STI, MRI, Options.MCOptions);
164     if (!MCE || !MAB)
165       return true;
166 
167     // Don't waste memory on names of temp labels.
168     Context.setUseNamesOnTempLabels(false);
169 
170     Triple T(getTargetTriple().str());
171     AsmStreamer.reset(getTarget().createMCObjectStreamer(
172         T, Context, std::unique_ptr<MCAsmBackend>(MAB),
173         DwoOut ? MAB->createDwoObjectWriter(Out, *DwoOut)
174                : MAB->createObjectWriter(Out),
175         std::unique_ptr<MCCodeEmitter>(MCE), STI, Options.MCOptions.MCRelaxAll,
176         Options.MCOptions.MCIncrementalLinkerCompatible,
177         /*DWARFMustBeAtTheEnd*/ true));
178     break;
179   }
180   case CGFT_Null:
181     // The Null output is intended for use for performance analysis and testing,
182     // not real users.
183     AsmStreamer.reset(getTarget().createNullStreamer(Context));
184     break;
185   }
186 
187   // Create the AsmPrinter, which takes ownership of AsmStreamer if successful.
188   FunctionPass *Printer =
189       getTarget().createAsmPrinter(*this, std::move(AsmStreamer));
190   if (!Printer)
191     return true;
192 
193   PM.add(Printer);
194   return false;
195 }
196 
197 bool LLVMTargetMachine::addPassesToEmitFile(PassManagerBase &PM,
198                                             raw_pwrite_stream &Out,
199                                             raw_pwrite_stream *DwoOut,
200                                             CodeGenFileType FileType,
201                                             bool DisableVerify,
202                                             MachineModuleInfo *MMI) {
203   // Add common CodeGen passes.
204   bool WillCompleteCodeGenPipeline = true;
205   MCContext *Context = addPassesToGenerateCode(
206       this, PM, DisableVerify, WillCompleteCodeGenPipeline, Out, MMI);
207   if (!Context)
208     return true;
209 
210   if (WillCompleteCodeGenPipeline &&
211       addAsmPrinter(PM, Out, DwoOut, FileType, *Context))
212     return true;
213 
214   PM.add(createFreeMachineFunctionPass());
215   return false;
216 }
217 
218 /// addPassesToEmitMC - Add passes to the specified pass manager to get
219 /// machine code emitted with the MCJIT. This method returns true if machine
220 /// code is not supported. It fills the MCContext Ctx pointer which can be
221 /// used to build custom MCStreamer.
222 ///
223 bool LLVMTargetMachine::addPassesToEmitMC(PassManagerBase &PM, MCContext *&Ctx,
224                                           raw_pwrite_stream &Out,
225                                           bool DisableVerify) {
226   // Add common CodeGen passes.
227   bool WillCompleteCodeGenPipeline = true;
228   Ctx = addPassesToGenerateCode(this, PM, DisableVerify,
229                                 WillCompleteCodeGenPipeline, Out,
230                                 /*MachineModuleInfo*/ nullptr);
231   if (!Ctx)
232     return true;
233   assert(WillCompleteCodeGenPipeline && "CodeGen pipeline has been altered");
234 
235   if (Options.MCOptions.MCSaveTempLabels)
236     Ctx->setAllowTemporaryLabels(false);
237 
238   // Create the code emitter for the target if it exists.  If not, .o file
239   // emission fails.
240   const MCSubtargetInfo &STI = *getMCSubtargetInfo();
241   const MCRegisterInfo &MRI = *getMCRegisterInfo();
242   MCCodeEmitter *MCE =
243       getTarget().createMCCodeEmitter(*getMCInstrInfo(), MRI, *Ctx);
244   MCAsmBackend *MAB =
245       getTarget().createMCAsmBackend(STI, MRI, Options.MCOptions);
246   if (!MCE || !MAB)
247     return true;
248 
249   const Triple &T = getTargetTriple();
250   std::unique_ptr<MCStreamer> AsmStreamer(getTarget().createMCObjectStreamer(
251       T, *Ctx, std::unique_ptr<MCAsmBackend>(MAB), MAB->createObjectWriter(Out),
252       std::unique_ptr<MCCodeEmitter>(MCE), STI, Options.MCOptions.MCRelaxAll,
253       Options.MCOptions.MCIncrementalLinkerCompatible,
254       /*DWARFMustBeAtTheEnd*/ true));
255 
256   // Create the AsmPrinter, which takes ownership of AsmStreamer if successful.
257   FunctionPass *Printer =
258       getTarget().createAsmPrinter(*this, std::move(AsmStreamer));
259   if (!Printer)
260     return true;
261 
262   PM.add(Printer);
263   PM.add(createFreeMachineFunctionPass());
264 
265   return false; // success!
266 }
267