1 //===-- LLVMTargetMachine.cpp - Implement the LLVMTargetMachine class -----===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file implements the LLVMTargetMachine class.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "llvm/Analysis/Passes.h"
14 #include "llvm/CodeGen/AsmPrinter.h"
15 #include "llvm/CodeGen/BasicTTIImpl.h"
16 #include "llvm/CodeGen/MachineModuleInfo.h"
17 #include "llvm/CodeGen/Passes.h"
18 #include "llvm/CodeGen/TargetPassConfig.h"
19 #include "llvm/IR/LegacyPassManager.h"
20 #include "llvm/MC/MCAsmBackend.h"
21 #include "llvm/MC/MCAsmInfo.h"
22 #include "llvm/MC/MCCodeEmitter.h"
23 #include "llvm/MC/MCContext.h"
24 #include "llvm/MC/MCInstrInfo.h"
25 #include "llvm/MC/MCObjectWriter.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 using namespace llvm;
36 
37 static cl::opt<bool> EnableTrapUnreachable("trap-unreachable",
38   cl::Hidden, cl::ZeroOrMore, cl::init(false),
39   cl::desc("Enable generating trap for unreachable"));
40 
41 void LLVMTargetMachine::initAsmInfo() {
42   MRI.reset(TheTarget.createMCRegInfo(getTargetTriple().str()));
43   MII.reset(TheTarget.createMCInstrInfo());
44   // FIXME: Having an MCSubtargetInfo on the target machine is a hack due
45   // to some backends having subtarget feature dependent module level
46   // code generation. This is similar to the hack in the AsmPrinter for
47   // module level assembly etc.
48   STI.reset(TheTarget.createMCSubtargetInfo(
49       getTargetTriple().str(), getTargetCPU(), getTargetFeatureString()));
50 
51   MCAsmInfo *TmpAsmInfo = TheTarget.createMCAsmInfo(
52       *MRI, getTargetTriple().str(), Options.MCOptions);
53   // TargetSelect.h moved to a different directory between LLVM 2.9 and 3.0,
54   // and if the old one gets included then MCAsmInfo will be NULL and
55   // we'll crash later.
56   // Provide the user with a useful error message about what's wrong.
57   assert(TmpAsmInfo && "MCAsmInfo not initialized. "
58          "Make sure you include the correct TargetSelect.h"
59          "and that InitializeAllTargetMCs() is being invoked!");
60 
61   if (Options.DisableIntegratedAS)
62     TmpAsmInfo->setUseIntegratedAssembler(false);
63 
64   TmpAsmInfo->setPreserveAsmComments(Options.MCOptions.PreserveAsmComments);
65 
66   TmpAsmInfo->setCompressDebugSections(Options.CompressDebugSections);
67 
68   TmpAsmInfo->setRelaxELFRelocations(Options.RelaxELFRelocations);
69 
70   if (Options.ExceptionModel != ExceptionHandling::None)
71     TmpAsmInfo->setExceptionsType(Options.ExceptionModel);
72 
73   AsmInfo.reset(TmpAsmInfo);
74 }
75 
76 LLVMTargetMachine::LLVMTargetMachine(const Target &T,
77                                      StringRef DataLayoutString,
78                                      const Triple &TT, StringRef CPU,
79                                      StringRef FS, const TargetOptions &Options,
80                                      Reloc::Model RM, CodeModel::Model CM,
81                                      CodeGenOpt::Level OL)
82     : TargetMachine(T, DataLayoutString, TT, CPU, FS, Options) {
83   this->RM = RM;
84   this->CMModel = CM;
85   this->OptLevel = OL;
86 
87   if (EnableTrapUnreachable)
88     this->Options.TrapUnreachable = true;
89 }
90 
91 TargetTransformInfo
92 LLVMTargetMachine::getTargetTransformInfo(const Function &F) {
93   return TargetTransformInfo(BasicTTIImpl(this, F));
94 }
95 
96 /// addPassesToX helper drives creation and initialization of TargetPassConfig.
97 static TargetPassConfig *
98 addPassesToGenerateCode(LLVMTargetMachine &TM, PassManagerBase &PM,
99                         bool DisableVerify,
100                         MachineModuleInfoWrapperPass &MMIWP) {
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(&MMIWP);
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 = std::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     Triple T(getTargetTriple().str());
161     AsmStreamer.reset(getTarget().createMCObjectStreamer(
162         T, Context, std::unique_ptr<MCAsmBackend>(MAB),
163         DwoOut ? MAB->createDwoObjectWriter(Out, *DwoOut)
164                : MAB->createObjectWriter(Out),
165         std::unique_ptr<MCCodeEmitter>(MCE), STI, Options.MCOptions.MCRelaxAll,
166         Options.MCOptions.MCIncrementalLinkerCompatible,
167         /*DWARFMustBeAtTheEnd*/ true));
168     break;
169   }
170   case CGFT_Null:
171     // The Null output is intended for use for performance analysis and testing,
172     // not real users.
173     AsmStreamer.reset(getTarget().createNullStreamer(Context));
174     break;
175   }
176 
177   // Create the AsmPrinter, which takes ownership of AsmStreamer if successful.
178   FunctionPass *Printer =
179       getTarget().createAsmPrinter(*this, std::move(AsmStreamer));
180   if (!Printer)
181     return true;
182 
183   PM.add(Printer);
184   return false;
185 }
186 
187 bool LLVMTargetMachine::addPassesToEmitFile(
188     PassManagerBase &PM, raw_pwrite_stream &Out, raw_pwrite_stream *DwoOut,
189     CodeGenFileType FileType, bool DisableVerify,
190     MachineModuleInfoWrapperPass *MMIWP) {
191   // Add common CodeGen passes.
192   if (!MMIWP)
193     MMIWP = new MachineModuleInfoWrapperPass(this);
194   TargetPassConfig *PassConfig =
195       addPassesToGenerateCode(*this, PM, DisableVerify, *MMIWP);
196   if (!PassConfig)
197     return true;
198 
199   if (TargetPassConfig::willCompleteCodeGenPipeline()) {
200     if (addAsmPrinter(PM, Out, DwoOut, FileType, MMIWP->getMMI().getContext()))
201       return true;
202   } else {
203     // MIR printing is redundant with -filetype=null.
204     if (FileType != CGFT_Null)
205       PM.add(createPrintMIRPass(Out));
206   }
207 
208   PM.add(createFreeMachineFunctionPass());
209   return false;
210 }
211 
212 /// addPassesToEmitMC - Add passes to the specified pass manager to get
213 /// machine code emitted with the MCJIT. This method returns true if machine
214 /// code is not supported. It fills the MCContext Ctx pointer which can be
215 /// used to build custom MCStreamer.
216 ///
217 bool LLVMTargetMachine::addPassesToEmitMC(PassManagerBase &PM, MCContext *&Ctx,
218                                           raw_pwrite_stream &Out,
219                                           bool DisableVerify) {
220   // Add common CodeGen passes.
221   MachineModuleInfoWrapperPass *MMIWP = new MachineModuleInfoWrapperPass(this);
222   TargetPassConfig *PassConfig =
223       addPassesToGenerateCode(*this, PM, DisableVerify, *MMIWP);
224   if (!PassConfig)
225     return true;
226   assert(TargetPassConfig::willCompleteCodeGenPipeline() &&
227          "Cannot emit MC with limited codegen pipeline");
228 
229   Ctx = &MMIWP->getMMI().getContext();
230   if (Options.MCOptions.MCSaveTempLabels)
231     Ctx->setAllowTemporaryLabels(false);
232 
233   // Create the code emitter for the target if it exists.  If not, .o file
234   // emission fails.
235   const MCSubtargetInfo &STI = *getMCSubtargetInfo();
236   const MCRegisterInfo &MRI = *getMCRegisterInfo();
237   MCCodeEmitter *MCE =
238       getTarget().createMCCodeEmitter(*getMCInstrInfo(), MRI, *Ctx);
239   MCAsmBackend *MAB =
240       getTarget().createMCAsmBackend(STI, MRI, Options.MCOptions);
241   if (!MCE || !MAB)
242     return true;
243 
244   const Triple &T = getTargetTriple();
245   std::unique_ptr<MCStreamer> AsmStreamer(getTarget().createMCObjectStreamer(
246       T, *Ctx, std::unique_ptr<MCAsmBackend>(MAB), MAB->createObjectWriter(Out),
247       std::unique_ptr<MCCodeEmitter>(MCE), STI, Options.MCOptions.MCRelaxAll,
248       Options.MCOptions.MCIncrementalLinkerCompatible,
249       /*DWARFMustBeAtTheEnd*/ true));
250 
251   // Create the AsmPrinter, which takes ownership of AsmStreamer if successful.
252   FunctionPass *Printer =
253       getTarget().createAsmPrinter(*this, std::move(AsmStreamer));
254   if (!Printer)
255     return true;
256 
257   PM.add(Printer);
258   PM.add(createFreeMachineFunctionPass());
259 
260   return false; // success!
261 }
262