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/ADT/OwningPtr.h"
16 #include "llvm/CodeGen/AsmPrinter.h"
17 #include "llvm/CodeGen/MachineFunctionAnalysis.h"
18 #include "llvm/CodeGen/MachineModuleInfo.h"
19 #include "llvm/CodeGen/Passes.h"
20 #include "llvm/IR/IRPrintingPasses.h"
21 #include "llvm/MC/MCAsmInfo.h"
22 #include "llvm/MC/MCContext.h"
23 #include "llvm/MC/MCInstrInfo.h"
24 #include "llvm/MC/MCStreamer.h"
25 #include "llvm/MC/MCSubtargetInfo.h"
26 #include "llvm/PassManager.h"
27 #include "llvm/Support/CommandLine.h"
28 #include "llvm/Support/ErrorHandling.h"
29 #include "llvm/Support/FormattedStream.h"
30 #include "llvm/Support/TargetRegistry.h"
31 #include "llvm/Target/TargetInstrInfo.h"
32 #include "llvm/Target/TargetLowering.h"
33 #include "llvm/Target/TargetLoweringObjectFile.h"
34 #include "llvm/Target/TargetOptions.h"
35 #include "llvm/Target/TargetRegisterInfo.h"
36 #include "llvm/Target/TargetSubtargetInfo.h"
37 #include "llvm/Transforms/Scalar.h"
38 using namespace llvm;
39 
40 // Enable or disable FastISel. Both options are needed, because
41 // FastISel is enabled by default with -fast, and we wish to be
42 // able to enable or disable fast-isel independently from -O0.
43 static cl::opt<cl::boolOrDefault>
44 EnableFastISelOption("fast-isel", cl::Hidden,
45   cl::desc("Enable the \"fast\" instruction selector"));
46 
47 static cl::opt<bool> ShowMCEncoding("show-mc-encoding", cl::Hidden,
48     cl::desc("Show encoding in .s output"));
49 static cl::opt<bool> ShowMCInst("show-mc-inst", cl::Hidden,
50     cl::desc("Show instruction structure in .s output"));
51 
52 static cl::opt<cl::boolOrDefault>
53 AsmVerbose("asm-verbose", cl::desc("Add comments to directives."),
54            cl::init(cl::BOU_UNSET));
55 
56 static cl::opt<bool>
57 NoIntegratedAssembler("no-integrated-as", cl::Hidden,
58                       cl::desc("Disable integrated assembler"));
59 
60 static bool getVerboseAsm() {
61   switch (AsmVerbose) {
62   case cl::BOU_UNSET: return TargetMachine::getAsmVerbosityDefault();
63   case cl::BOU_TRUE:  return true;
64   case cl::BOU_FALSE: return false;
65   }
66   llvm_unreachable("Invalid verbose asm state");
67 }
68 
69 void LLVMTargetMachine::initAsmInfo() {
70   MCAsmInfo *TmpAsmInfo = TheTarget.createMCAsmInfo(*getRegisterInfo(),
71                                                     TargetTriple);
72   // TargetSelect.h moved to a different directory between LLVM 2.9 and 3.0,
73   // and if the old one gets included then MCAsmInfo will be NULL and
74   // we'll crash later.
75   // Provide the user with a useful error message about what's wrong.
76   assert(TmpAsmInfo && "MCAsmInfo not initialized. "
77          "Make sure you include the correct TargetSelect.h"
78          "and that InitializeAllTargetMCs() is being invoked!");
79 
80   if (NoIntegratedAssembler)
81     TmpAsmInfo->setUseIntegratedAssembler(false);
82 
83   AsmInfo = TmpAsmInfo;
84 }
85 
86 LLVMTargetMachine::LLVMTargetMachine(const Target &T, StringRef Triple,
87                                      StringRef CPU, StringRef FS,
88                                      TargetOptions Options,
89                                      Reloc::Model RM, CodeModel::Model CM,
90                                      CodeGenOpt::Level OL)
91   : TargetMachine(T, Triple, CPU, FS, Options) {
92   CodeGenInfo = T.createMCCodeGenInfo(Triple, RM, CM, OL);
93 }
94 
95 void LLVMTargetMachine::addAnalysisPasses(PassManagerBase &PM) {
96   PM.add(createBasicTargetTransformInfoPass(this));
97 }
98 
99 /// addPassesToX helper drives creation and initialization of TargetPassConfig.
100 static MCContext *addPassesToGenerateCode(LLVMTargetMachine *TM,
101                                           PassManagerBase &PM,
102                                           bool DisableVerify,
103                                           AnalysisID StartAfter,
104                                           AnalysisID StopAfter) {
105   // Add internal analysis passes from the target machine.
106   TM->addAnalysisPasses(PM);
107 
108   // Targets may override createPassConfig to provide a target-specific sublass.
109   TargetPassConfig *PassConfig = TM->createPassConfig(PM);
110   PassConfig->setStartStopPasses(StartAfter, StopAfter);
111 
112   // Set PassConfig options provided by TargetMachine.
113   PassConfig->setDisableVerify(DisableVerify);
114 
115   PM.add(PassConfig);
116 
117   PassConfig->addIRPasses();
118 
119   PassConfig->addCodeGenPrepare();
120 
121   PassConfig->addPassesToHandleExceptions();
122 
123   PassConfig->addISelPrepare();
124 
125   // Install a MachineModuleInfo class, which is an immutable pass that holds
126   // all the per-module stuff we're generating, including MCContext.
127   MachineModuleInfo *MMI =
128     new MachineModuleInfo(*TM->getMCAsmInfo(), *TM->getRegisterInfo(),
129                           &TM->getTargetLowering()->getObjFileLowering());
130   PM.add(MMI);
131 
132   // Set up a MachineFunction for the rest of CodeGen to work on.
133   PM.add(new MachineFunctionAnalysis(*TM));
134 
135   // Enable FastISel with -fast, but allow that to be overridden.
136   if (EnableFastISelOption == cl::BOU_TRUE ||
137       (TM->getOptLevel() == CodeGenOpt::None &&
138        EnableFastISelOption != cl::BOU_FALSE))
139     TM->setFastISel(true);
140 
141   // Ask the target for an isel.
142   if (PassConfig->addInstSelector())
143     return NULL;
144 
145   PassConfig->addMachinePasses();
146 
147   PassConfig->setInitialized();
148 
149   return &MMI->getContext();
150 }
151 
152 bool LLVMTargetMachine::addPassesToEmitFile(PassManagerBase &PM,
153                                             formatted_raw_ostream &Out,
154                                             CodeGenFileType FileType,
155                                             bool DisableVerify,
156                                             AnalysisID StartAfter,
157                                             AnalysisID StopAfter) {
158   // Add common CodeGen passes.
159   MCContext *Context = addPassesToGenerateCode(this, PM, DisableVerify,
160                                                StartAfter, StopAfter);
161   if (!Context)
162     return true;
163 
164   if (StopAfter) {
165     // FIXME: The intent is that this should eventually write out a YAML file,
166     // containing the LLVM IR, the machine-level IR (when stopping after a
167     // machine-level pass), and whatever other information is needed to
168     // deserialize the code and resume compilation.  For now, just write the
169     // LLVM IR.
170     PM.add(createPrintModulePass(Out));
171     return false;
172   }
173 
174   if (hasMCSaveTempLabels())
175     Context->setAllowTemporaryLabels(false);
176 
177   const MCAsmInfo &MAI = *getMCAsmInfo();
178   const MCRegisterInfo &MRI = *getRegisterInfo();
179   const MCInstrInfo &MII = *getInstrInfo();
180   const MCSubtargetInfo &STI = getSubtarget<MCSubtargetInfo>();
181   OwningPtr<MCStreamer> AsmStreamer;
182 
183   switch (FileType) {
184   case CGFT_AssemblyFile: {
185     MCInstPrinter *InstPrinter =
186       getTarget().createMCInstPrinter(MAI.getAssemblerDialect(), MAI,
187                                       MII, MRI, STI);
188 
189     // Create a code emitter if asked to show the encoding.
190     MCCodeEmitter *MCE = 0;
191     if (ShowMCEncoding)
192       MCE = getTarget().createMCCodeEmitter(MII, MRI, STI, *Context);
193 
194     MCAsmBackend *MAB = getTarget().createMCAsmBackend(MRI, getTargetTriple(),
195                                                        TargetCPU);
196     MCStreamer *S = getTarget().createAsmStreamer(*Context, Out,
197                                                   getVerboseAsm(),
198                                                   hasMCUseCFI(),
199                                                   hasMCUseDwarfDirectory(),
200                                                   InstPrinter,
201                                                   MCE, MAB,
202                                                   ShowMCInst);
203     AsmStreamer.reset(S);
204     break;
205   }
206   case CGFT_ObjectFile: {
207     // Create the code emitter for the target if it exists.  If not, .o file
208     // emission fails.
209     MCCodeEmitter *MCE = getTarget().createMCCodeEmitter(MII, MRI, STI,
210                                                          *Context);
211     MCAsmBackend *MAB = getTarget().createMCAsmBackend(MRI, getTargetTriple(),
212                                                        TargetCPU);
213     if (MCE == 0 || MAB == 0)
214       return true;
215 
216     AsmStreamer.reset(getTarget().createMCObjectStreamer(
217         getTargetTriple(), *Context, *MAB, Out, MCE, STI, hasMCRelaxAll(),
218         hasMCNoExecStack()));
219     break;
220   }
221   case CGFT_Null:
222     // The Null output is intended for use for performance analysis and testing,
223     // not real users.
224     AsmStreamer.reset(createNullStreamer(*Context));
225     break;
226   }
227 
228   // Create the AsmPrinter, which takes ownership of AsmStreamer if successful.
229   FunctionPass *Printer = getTarget().createAsmPrinter(*this, *AsmStreamer);
230   if (Printer == 0)
231     return true;
232 
233   // If successful, createAsmPrinter took ownership of AsmStreamer.
234   AsmStreamer.take();
235 
236   PM.add(Printer);
237 
238   return false;
239 }
240 
241 /// addPassesToEmitMachineCode - Add passes to the specified pass manager to
242 /// get machine code emitted.  This uses a JITCodeEmitter object to handle
243 /// actually outputting the machine code and resolving things like the address
244 /// of functions.  This method should return true if machine code emission is
245 /// not supported.
246 ///
247 bool LLVMTargetMachine::addPassesToEmitMachineCode(PassManagerBase &PM,
248                                                    JITCodeEmitter &JCE,
249                                                    bool DisableVerify) {
250   // Add common CodeGen passes.
251   MCContext *Context = addPassesToGenerateCode(this, PM, DisableVerify, 0, 0);
252   if (!Context)
253     return true;
254 
255   addCodeEmitter(PM, JCE);
256 
257   return false; // success!
258 }
259 
260 /// addPassesToEmitMC - Add passes to the specified pass manager to get
261 /// machine code emitted with the MCJIT. This method returns true if machine
262 /// code is not supported. It fills the MCContext Ctx pointer which can be
263 /// used to build custom MCStreamer.
264 ///
265 bool LLVMTargetMachine::addPassesToEmitMC(PassManagerBase &PM,
266                                           MCContext *&Ctx,
267                                           raw_ostream &Out,
268                                           bool DisableVerify) {
269   // Add common CodeGen passes.
270   Ctx = addPassesToGenerateCode(this, PM, DisableVerify, 0, 0);
271   if (!Ctx)
272     return true;
273 
274   if (hasMCSaveTempLabels())
275     Ctx->setAllowTemporaryLabels(false);
276 
277   // Create the code emitter for the target if it exists.  If not, .o file
278   // emission fails.
279   const MCRegisterInfo &MRI = *getRegisterInfo();
280   const MCSubtargetInfo &STI = getSubtarget<MCSubtargetInfo>();
281   MCCodeEmitter *MCE = getTarget().createMCCodeEmitter(*getInstrInfo(), MRI,
282                                                        STI, *Ctx);
283   MCAsmBackend *MAB = getTarget().createMCAsmBackend(MRI, getTargetTriple(),
284                                                      TargetCPU);
285   if (MCE == 0 || MAB == 0)
286     return true;
287 
288   OwningPtr<MCStreamer> AsmStreamer;
289   AsmStreamer.reset(getTarget().createMCObjectStreamer(
290       getTargetTriple(), *Ctx, *MAB, Out, MCE, STI, hasMCRelaxAll(),
291       hasMCNoExecStack()));
292 
293   // Create the AsmPrinter, which takes ownership of AsmStreamer if successful.
294   FunctionPass *Printer = getTarget().createAsmPrinter(*this, *AsmStreamer);
295   if (Printer == 0)
296     return true;
297 
298   // If successful, createAsmPrinter took ownership of AsmStreamer.
299   AsmStreamer.take();
300 
301   PM.add(Printer);
302 
303   return false; // success!
304 }
305