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/Target/TargetMachine.h"
15#include "llvm/Analysis/Passes.h"
16#include "llvm/CodeGen/AsmPrinter.h"
17#include "llvm/CodeGen/BasicTTIImpl.h"
18#include "llvm/CodeGen/MachineFunctionAnalysis.h"
19#include "llvm/CodeGen/MachineModuleInfo.h"
20#include "llvm/CodeGen/Passes.h"
21#include "llvm/IR/IRPrintingPasses.h"
22#include "llvm/IR/LegacyPassManager.h"
23#include "llvm/IR/Verifier.h"
24#include "llvm/MC/MCAsmInfo.h"
25#include "llvm/MC/MCContext.h"
26#include "llvm/MC/MCInstrInfo.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/TargetOptions.h"
35#include "llvm/Transforms/Scalar.h"
36using namespace llvm;
37
38// Enable or disable FastISel. Both options are needed, because
39// FastISel is enabled by default with -fast, and we wish to be
40// able to enable or disable fast-isel independently from -O0.
41static cl::opt<cl::boolOrDefault>
42EnableFastISelOption("fast-isel", cl::Hidden,
43  cl::desc("Enable the \"fast\" instruction selector"));
44
45void LLVMTargetMachine::initAsmInfo() {
46  MRI = TheTarget.createMCRegInfo(getTargetTriple().str());
47  MII = TheTarget.createMCInstrInfo();
48  // FIXME: Having an MCSubtargetInfo on the target machine is a hack due
49  // to some backends having subtarget feature dependent module level
50  // code generation. This is similar to the hack in the AsmPrinter for
51  // module level assembly etc.
52  STI = TheTarget.createMCSubtargetInfo(getTargetTriple().str(), getTargetCPU(),
53                                        getTargetFeatureString());
54
55  MCAsmInfo *TmpAsmInfo =
56      TheTarget.createMCAsmInfo(*MRI, getTargetTriple().str());
57  // TargetSelect.h moved to a different directory between LLVM 2.9 and 3.0,
58  // and if the old one gets included then MCAsmInfo will be NULL and
59  // we'll crash later.
60  // Provide the user with a useful error message about what's wrong.
61  assert(TmpAsmInfo && "MCAsmInfo not initialized. "
62         "Make sure you include the correct TargetSelect.h"
63         "and that InitializeAllTargetMCs() is being invoked!");
64
65  if (Options.DisableIntegratedAS)
66    TmpAsmInfo->setUseIntegratedAssembler(false);
67
68  if (Options.CompressDebugSections)
69    TmpAsmInfo->setCompressDebugSections(true);
70
71  AsmInfo = TmpAsmInfo;
72}
73
74LLVMTargetMachine::LLVMTargetMachine(const Target &T,
75                                     StringRef DataLayoutString,
76                                     const Triple &TT, StringRef CPU,
77                                     StringRef FS, TargetOptions Options,
78                                     Reloc::Model RM, CodeModel::Model CM,
79                                     CodeGenOpt::Level OL)
80    : TargetMachine(T, DataLayoutString, TT, CPU, FS, Options) {
81  CodeGenInfo = T.createMCCodeGenInfo(TT.str(), RM, CM, OL);
82}
83
84TargetIRAnalysis LLVMTargetMachine::getTargetIRAnalysis() {
85  return TargetIRAnalysis([this](const Function &F) {
86    return TargetTransformInfo(BasicTTIImpl(this, F));
87  });
88}
89
90/// addPassesToX helper drives creation and initialization of TargetPassConfig.
91static MCContext *
92addPassesToGenerateCode(LLVMTargetMachine *TM, PassManagerBase &PM,
93                        bool DisableVerify, AnalysisID StartBefore,
94                        AnalysisID StartAfter, AnalysisID StopAfter,
95                        MachineFunctionInitializer *MFInitializer = nullptr) {
96
97  // When in emulated TLS mode, add the LowerEmuTLS pass.
98  if (TM->Options.EmulatedTLS)
99    PM.add(createLowerEmuTLSPass(TM));
100
101  // Add internal analysis passes from the target machine.
102  PM.add(createTargetTransformInfoWrapperPass(TM->getTargetIRAnalysis()));
103
104  // Targets may override createPassConfig to provide a target-specific
105  // subclass.
106  TargetPassConfig *PassConfig = TM->createPassConfig(PM);
107  PassConfig->setStartStopPasses(StartBefore, StartAfter, StopAfter);
108
109  // Set PassConfig options provided by TargetMachine.
110  PassConfig->setDisableVerify(DisableVerify);
111
112  PM.add(PassConfig);
113
114  PassConfig->addIRPasses();
115
116  PassConfig->addCodeGenPrepare();
117
118  PassConfig->addPassesToHandleExceptions();
119
120  PassConfig->addISelPrepare();
121
122  // Install a MachineModuleInfo class, which is an immutable pass that holds
123  // all the per-module stuff we're generating, including MCContext.
124  MachineModuleInfo *MMI = new MachineModuleInfo(
125      *TM->getMCAsmInfo(), *TM->getMCRegisterInfo(), TM->getObjFileLowering());
126  PM.add(MMI);
127
128  // Set up a MachineFunction for the rest of CodeGen to work on.
129  PM.add(new MachineFunctionAnalysis(*TM, MFInitializer));
130
131  // Enable FastISel with -fast, but allow that to be overridden.
132  TM->setO0WantsFastISel(EnableFastISelOption != cl::BOU_FALSE);
133  if (EnableFastISelOption == cl::BOU_TRUE ||
134      (TM->getOptLevel() == CodeGenOpt::None &&
135       TM->getO0WantsFastISel()))
136    TM->setFastISel(true);
137
138  // Ask the target for an isel.
139  if (PassConfig->addInstSelector())
140    return nullptr;
141
142  PassConfig->addMachinePasses();
143
144  PassConfig->setInitialized();
145
146  return &MMI->getContext();
147}
148
149bool LLVMTargetMachine::addPassesToEmitFile(
150    PassManagerBase &PM, raw_pwrite_stream &Out, CodeGenFileType FileType,
151    bool DisableVerify, AnalysisID StartBefore, AnalysisID StartAfter,
152    AnalysisID StopAfter, MachineFunctionInitializer *MFInitializer) {
153  // Add common CodeGen passes.
154  MCContext *Context =
155      addPassesToGenerateCode(this, PM, DisableVerify, StartBefore, StartAfter,
156                              StopAfter, MFInitializer);
157  if (!Context)
158    return true;
159
160  if (StopAfter) {
161    PM.add(createPrintMIRPass(outs()));
162    return false;
163  }
164
165  if (Options.MCOptions.MCSaveTempLabels)
166    Context->setAllowTemporaryLabels(false);
167
168  const MCSubtargetInfo &STI = *getMCSubtargetInfo();
169  const MCAsmInfo &MAI = *getMCAsmInfo();
170  const MCRegisterInfo &MRI = *getMCRegisterInfo();
171  const MCInstrInfo &MII = *getMCInstrInfo();
172
173  std::unique_ptr<MCStreamer> AsmStreamer;
174
175  switch (FileType) {
176  case CGFT_AssemblyFile: {
177    MCInstPrinter *InstPrinter = getTarget().createMCInstPrinter(
178        getTargetTriple(), MAI.getAssemblerDialect(), MAI, MII, MRI);
179
180    // Create a code emitter if asked to show the encoding.
181    MCCodeEmitter *MCE = nullptr;
182    if (Options.MCOptions.ShowMCEncoding)
183      MCE = getTarget().createMCCodeEmitter(MII, MRI, *Context);
184
185    MCAsmBackend *MAB =
186        getTarget().createMCAsmBackend(MRI, getTargetTriple().str(), TargetCPU);
187    auto FOut = llvm::make_unique<formatted_raw_ostream>(Out);
188    MCStreamer *S = getTarget().createAsmStreamer(
189        *Context, std::move(FOut), Options.MCOptions.AsmVerbose,
190        Options.MCOptions.MCUseDwarfDirectory, InstPrinter, MCE, MAB,
191        Options.MCOptions.ShowMCInst);
192    AsmStreamer.reset(S);
193    break;
194  }
195  case CGFT_ObjectFile: {
196    // Create the code emitter for the target if it exists.  If not, .o file
197    // emission fails.
198    MCCodeEmitter *MCE = getTarget().createMCCodeEmitter(MII, MRI, *Context);
199    MCAsmBackend *MAB =
200        getTarget().createMCAsmBackend(MRI, getTargetTriple().str(), TargetCPU);
201    if (!MCE || !MAB)
202      return true;
203
204    // Don't waste memory on names of temp labels.
205    Context->setUseNamesOnTempLabels(false);
206
207    Triple T(getTargetTriple().str());
208    AsmStreamer.reset(getTarget().createMCObjectStreamer(
209        T, *Context, *MAB, Out, MCE, STI, Options.MCOptions.MCRelaxAll,
210        Options.MCOptions.MCIncrementalLinkerCompatible,
211        /*DWARFMustBeAtTheEnd*/ true));
212    break;
213  }
214  case CGFT_Null:
215    // The Null output is intended for use for performance analysis and testing,
216    // not real users.
217    AsmStreamer.reset(getTarget().createNullStreamer(*Context));
218    break;
219  }
220
221  // Create the AsmPrinter, which takes ownership of AsmStreamer if successful.
222  FunctionPass *Printer =
223      getTarget().createAsmPrinter(*this, std::move(AsmStreamer));
224  if (!Printer)
225    return true;
226
227  PM.add(Printer);
228
229  return false;
230}
231
232/// addPassesToEmitMC - Add passes to the specified pass manager to get
233/// machine code emitted with the MCJIT. This method returns true if machine
234/// code is not supported. It fills the MCContext Ctx pointer which can be
235/// used to build custom MCStreamer.
236///
237bool LLVMTargetMachine::addPassesToEmitMC(PassManagerBase &PM, MCContext *&Ctx,
238                                          raw_pwrite_stream &Out,
239                                          bool DisableVerify) {
240  // Add common CodeGen passes.
241  Ctx = addPassesToGenerateCode(this, PM, DisableVerify, nullptr, nullptr,
242                                nullptr);
243  if (!Ctx)
244    return true;
245
246  if (Options.MCOptions.MCSaveTempLabels)
247    Ctx->setAllowTemporaryLabels(false);
248
249  // Create the code emitter for the target if it exists.  If not, .o file
250  // emission fails.
251  const MCRegisterInfo &MRI = *getMCRegisterInfo();
252  MCCodeEmitter *MCE =
253      getTarget().createMCCodeEmitter(*getMCInstrInfo(), MRI, *Ctx);
254  MCAsmBackend *MAB =
255      getTarget().createMCAsmBackend(MRI, getTargetTriple().str(), TargetCPU);
256  if (!MCE || !MAB)
257    return true;
258
259  const Triple &T = getTargetTriple();
260  const MCSubtargetInfo &STI = *getMCSubtargetInfo();
261  std::unique_ptr<MCStreamer> AsmStreamer(getTarget().createMCObjectStreamer(
262      T, *Ctx, *MAB, Out, MCE, STI, Options.MCOptions.MCRelaxAll,
263      Options.MCOptions.MCIncrementalLinkerCompatible,
264      /*DWARFMustBeAtTheEnd*/ true));
265
266  // Create the AsmPrinter, which takes ownership of AsmStreamer if successful.
267  FunctionPass *Printer =
268      getTarget().createAsmPrinter(*this, std::move(AsmStreamer));
269  if (!Printer)
270    return true;
271
272  PM.add(Printer);
273
274  return false; // success!
275}
276