lib/CodeGen/LLVMTargetMachine.cpp

   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/PassManager.h"
  16 #include "llvm/Pass.h"
  17 #include "llvm/Assembly/PrintModulePass.h"
  18 #include "llvm/Analysis/LoopPass.h"
  19 #include "llvm/CodeGen/Passes.h"
  20 #include "llvm/CodeGen/GCStrategy.h"
  21 #include "llvm/CodeGen/MachineFunctionAnalysis.h"
  22 #include "llvm/Target/TargetOptions.h"
  23 #include "llvm/Target/TargetAsmInfo.h"
  24 #include "llvm/Target/TargetRegistry.h"
  25 #include "llvm/Transforms/Scalar.h"
  26 #include "llvm/Support/CommandLine.h"
  27 #include "llvm/Support/FormattedStream.h"
  28 using namespace llvm;
  29
  30 namespace llvm {
  31   bool EnableFastISel;
  32 }
  33
  34 static cl::opt<bool> PrintLSR("print-lsr-output", cl::Hidden,
  35     cl::desc("Print LLVM IR produced by the loop-reduce pass"));
  36 static cl::opt<bool> PrintISelInput("print-isel-input", cl::Hidden,
  37     cl::desc("Print LLVM IR input to isel pass"));
  38 static cl::opt<bool> PrintEmittedAsm("print-emitted-asm", cl::Hidden,
  39     cl::desc("Dump emitter generated instructions as assembly"));
  40 static cl::opt<bool> PrintGCInfo("print-gc", cl::Hidden,
  41     cl::desc("Dump garbage collector data"));
  42 static cl::opt<bool> VerifyMachineCode("verify-machineinstrs", cl::Hidden,
  43     cl::desc("Verify generated machine code"),
  44     cl::init(getenv("LLVM_VERIFY_MACHINEINSTRS")!=NULL));
  45
  46 // When this works it will be on by default.
  47 static cl::opt<bool>
  48 DisablePostRAScheduler("disable-post-RA-scheduler",
  49                        cl::desc("Disable scheduling after register allocation"),
  50                        cl::init(true));
  51
  52 // Enable or disable FastISel. Both options are needed, because
  53 // FastISel is enabled by default with -fast, and we wish to be
  54 // able to enable or disable fast-isel independently from -fast.
  55 static cl::opt<cl::boolOrDefault>
  56 EnableFastISelOption("fast-isel", cl::Hidden,
  57   cl::desc("Enable the experimental \"fast\" instruction selector"));
  58
  59 FileModel::Model
  60 LLVMTargetMachine::addPassesToEmitFile(PassManagerBase &PM,
  61                                        formatted_raw_ostream &Out,
  62                                        CodeGenFileType FileType,
  63                                        CodeGenOpt::Level OptLevel) {
  64   // Add common CodeGen passes.
  65   if (addCommonCodeGenPasses(PM, OptLevel))
  66     return FileModel::Error;
  67
  68   // Fold redundant debug labels.
  69   PM.add(createDebugLabelFoldingPass());
  70
  71   if (PrintMachineCode)
  72     PM.add(createMachineFunctionPrinterPass(cerr));
  73
  74   if (addPreEmitPass(PM, OptLevel) && PrintMachineCode)
  75     PM.add(createMachineFunctionPrinterPass(cerr));
  76
  77   if (OptLevel != CodeGenOpt::None)
  78     PM.add(createCodePlacementOptPass());
  79
  80   switch (FileType) {
  81   default:
  82     break;
  83   case TargetMachine::AssemblyFile:
  84     if (addAssemblyEmitter(PM, OptLevel, getAsmVerbosityDefault(), Out))
  85       return FileModel::Error;
  86     return FileModel::AsmFile;
  87   case TargetMachine::ObjectFile:
  88     if (getMachOWriterInfo())
  89       return FileModel::MachOFile;
  90     else if (getELFWriterInfo())
  91       return FileModel::ElfFile;
  92   }
  93
  94   return FileModel::Error;
  95 }
  96
  97 bool LLVMTargetMachine::addAssemblyEmitter(PassManagerBase &PM,
  98                                            CodeGenOpt::Level OptLevel,
  99                                            bool Verbose,
 100                                            formatted_raw_ostream &Out) {
 101   FunctionPass *Printer = getTarget().createAsmPrinter(Out, *this, Verbose);
 102   if (!Printer)
 103     return true;
 104
 105   PM.add(Printer);
 106   return false;
 107 }
 108
 109 /// addPassesToEmitFileFinish - If the passes to emit the specified file had to
 110 /// be split up (e.g., to add an object writer pass), this method can be used to
 111 /// finish up adding passes to emit the file, if necessary.
 112 bool LLVMTargetMachine::addPassesToEmitFileFinish(PassManagerBase &PM,
 113                                                   MachineCodeEmitter *MCE,
 114                                                   CodeGenOpt::Level OptLevel) {
 115   if (MCE)
 116     addSimpleCodeEmitter(PM, OptLevel, *MCE);
 117   if (PrintEmittedAsm)
 118     addAssemblyEmitter(PM, OptLevel, true, ferrs());
 119
 120   PM.add(createGCInfoDeleter());
 121
 122   return false; // success!
 123 }
 124
 125 /// addPassesToEmitFileFinish - If the passes to emit the specified file had to
 126 /// be split up (e.g., to add an object writer pass), this method can be used to
 127 /// finish up adding passes to emit the file, if necessary.
 128 bool LLVMTargetMachine::addPassesToEmitFileFinish(PassManagerBase &PM,
 129                                                   JITCodeEmitter *JCE,
 130                                                   CodeGenOpt::Level OptLevel) {
 131   if (JCE)
 132     addSimpleCodeEmitter(PM, OptLevel, *JCE);
 133   if (PrintEmittedAsm)
 134     addAssemblyEmitter(PM, OptLevel, true, ferrs());
 135
 136   PM.add(createGCInfoDeleter());
 137
 138   return false; // success!
 139 }
 140
 141 /// addPassesToEmitFileFinish - If the passes to emit the specified file had to
 142 /// be split up (e.g., to add an object writer pass), this method can be used to
 143 /// finish up adding passes to emit the file, if necessary.
 144 bool LLVMTargetMachine::addPassesToEmitFileFinish(PassManagerBase &PM,
 145                                                   ObjectCodeEmitter *OCE,
 146                                                   CodeGenOpt::Level OptLevel) {
 147   if (OCE)
 148     addSimpleCodeEmitter(PM, OptLevel, *OCE);
 149   if (PrintEmittedAsm)
 150     addAssemblyEmitter(PM, OptLevel, true, ferrs());
 151
 152   PM.add(createGCInfoDeleter());
 153
 154   return false; // success!
 155 }
 156
 157 /// addPassesToEmitMachineCode - Add passes to the specified pass manager to
 158 /// get machine code emitted.  This uses a MachineCodeEmitter object to handle
 159 /// actually outputting the machine code and resolving things like the address
 160 /// of functions.  This method should returns true if machine code emission is
 161 /// not supported.
 162 ///
 163 bool LLVMTargetMachine::addPassesToEmitMachineCode(PassManagerBase &PM,
 164                                                    MachineCodeEmitter &MCE,
 165                                                    CodeGenOpt::Level OptLevel) {
 166   // Add common CodeGen passes.
 167   if (addCommonCodeGenPasses(PM, OptLevel))
 168     return true;
 169
 170   if (addPreEmitPass(PM, OptLevel) && PrintMachineCode)
 171     PM.add(createMachineFunctionPrinterPass(cerr));
 172
 173   addCodeEmitter(PM, OptLevel, MCE);
 174   if (PrintEmittedAsm)
 175     addAssemblyEmitter(PM, OptLevel, true, ferrs());
 176
 177   PM.add(createGCInfoDeleter());
 178
 179   return false; // success!
 180 }
 181
 182 /// addPassesToEmitMachineCode - Add passes to the specified pass manager to
 183 /// get machine code emitted.  This uses a MachineCodeEmitter object to handle
 184 /// actually outputting the machine code and resolving things like the address
 185 /// of functions.  This method should returns true if machine code emission is
 186 /// not supported.
 187 ///
 188 bool LLVMTargetMachine::addPassesToEmitMachineCode(PassManagerBase &PM,
 189                                                    JITCodeEmitter &JCE,
 190                                                    CodeGenOpt::Level OptLevel) {
 191   // Add common CodeGen passes.
 192   if (addCommonCodeGenPasses(PM, OptLevel))
 193     return true;
 194
 195   if (addPreEmitPass(PM, OptLevel) && PrintMachineCode)
 196     PM.add(createMachineFunctionPrinterPass(cerr));
 197
 198   addCodeEmitter(PM, OptLevel, JCE);
 199   if (PrintEmittedAsm)
 200     addAssemblyEmitter(PM, OptLevel, true, ferrs());
 201
 202   PM.add(createGCInfoDeleter());
 203
 204   return false; // success!
 205 }
 206
 207 static void printAndVerify(PassManagerBase &PM,
 208                            bool allowDoubleDefs = false) {
 209   if (PrintMachineCode)
 210     PM.add(createMachineFunctionPrinterPass(cerr));
 211
 212   if (VerifyMachineCode)
 213     PM.add(createMachineVerifierPass(allowDoubleDefs));
 214 }
 215
 216 /// addCommonCodeGenPasses - Add standard LLVM codegen passes used for both
 217 /// emitting to assembly files or machine code output.
 218 ///
 219 bool LLVMTargetMachine::addCommonCodeGenPasses(PassManagerBase &PM,
 220                                                CodeGenOpt::Level OptLevel) {
 221   // Standard LLVM-Level Passes.
 222
 223   // Run loop strength reduction before anything else.
 224   if (OptLevel != CodeGenOpt::None) {
 225     PM.add(createLoopStrengthReducePass(getTargetLowering()));
 226     if (PrintLSR)
 227       PM.add(createPrintFunctionPass("\n\n*** Code after LSR ***\n", &errs()));
 228   }
 229
 230   // Turn exception handling constructs into something the code generators can
 231   // handle.
 232   if (!getTargetAsmInfo()->doesSupportExceptionHandling())
 233     PM.add(createLowerInvokePass(getTargetLowering()));
 234   else
 235     PM.add(createDwarfEHPass(getTargetLowering(), OptLevel==CodeGenOpt::None));
 236
 237   PM.add(createGCLoweringPass());
 238
 239   // Make sure that no unreachable blocks are instruction selected.
 240   PM.add(createUnreachableBlockEliminationPass());
 241
 242   if (OptLevel != CodeGenOpt::None)
 243     PM.add(createCodeGenPreparePass(getTargetLowering()));
 244
 245   PM.add(createStackProtectorPass(getTargetLowering()));
 246
 247   if (PrintISelInput)
 248     PM.add(createPrintFunctionPass("\n\n"
 249                                    "*** Final LLVM Code input to ISel ***\n",
 250                                    &errs()));
 251
 252   // Standard Lower-Level Passes.
 253
 254   // Set up a MachineFunction for the rest of CodeGen to work on.
 255   PM.add(new MachineFunctionAnalysis(*this, OptLevel));
 256
 257   // Enable FastISel with -fast, but allow that to be overridden.
 258   if (EnableFastISelOption == cl::BOU_TRUE ||
 259       (OptLevel == CodeGenOpt::None && EnableFastISelOption != cl::BOU_FALSE))
 260     EnableFastISel = true;
 261
 262   // Ask the target for an isel.
 263   if (addInstSelector(PM, OptLevel))
 264     return true;
 265
 266   // Print the instruction selected machine code...
 267   printAndVerify(PM, /* allowDoubleDefs= */ true);
 268
 269   if (OptLevel != CodeGenOpt::None) {
 270     PM.add(createMachineLICMPass());
 271     PM.add(createMachineSinkingPass());
 272     printAndVerify(PM, /* allowDoubleDefs= */ true);
 273   }
 274
 275   // Run pre-ra passes.
 276   if (addPreRegAlloc(PM, OptLevel))
 277     printAndVerify(PM);
 278
 279   // Perform register allocation.
 280   PM.add(createRegisterAllocator());
 281
 282   // Perform stack slot coloring.
 283   if (OptLevel != CodeGenOpt::None)
 284     // FIXME: Re-enable coloring with register when it's capable of adding
 285     // kill markers.
 286     PM.add(createStackSlotColoringPass(false));
 287
 288   printAndVerify(PM);           // Print the register-allocated code
 289
 290   // Run post-ra passes.
 291   if (addPostRegAlloc(PM, OptLevel))
 292     printAndVerify(PM);
 293
 294   PM.add(createLowerSubregsPass());
 295   printAndVerify(PM);
 296
 297   // Insert prolog/epilog code.  Eliminate abstract frame index references...
 298   PM.add(createPrologEpilogCodeInserter());
 299   printAndVerify(PM);
 300
 301   // Second pass scheduler.
 302   if (OptLevel != CodeGenOpt::None && !DisablePostRAScheduler) {
 303     PM.add(createPostRAScheduler());
 304     printAndVerify(PM);
 305   }
 306
 307   // Branch folding must be run after regalloc and prolog/epilog insertion.
 308   if (OptLevel != CodeGenOpt::None) {
 309     PM.add(createBranchFoldingPass(getEnableTailMergeDefault()));
 310     printAndVerify(PM);
 311   }
 312
 313   PM.add(createGCMachineCodeAnalysisPass());
 314   printAndVerify(PM);
 315
 316   if (PrintGCInfo)
 317     PM.add(createGCInfoPrinter(*cerr));
 318
 319   return false;
 320 }