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