lib/Target/TargetMachine.cpp

   1 //===-- TargetMachine.cpp - General Target Information ---------------------==//
   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 describes the general parts of a Target machine.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "llvm/CodeGen/MachineFunction.h"
  15 #include "llvm/CodeGen/MachineFrameInfo.h"
  16 #include "llvm/MC/MCAsmInfo.h"
  17 #include "llvm/Target/TargetMachine.h"
  18 #include "llvm/Target/TargetOptions.h"
  19 #include "llvm/Support/CommandLine.h"
  20 using namespace llvm;
  21
  22 //---------------------------------------------------------------------------
  23 // Command-line options that tend to be useful on more than one back-end.
  24 //
  25
  26 namespace llvm {
  27   bool LessPreciseFPMADOption;
  28   bool PrintMachineCode;
  29   bool NoFramePointerElim;
  30   bool NoFramePointerElimNonLeaf;
  31   bool NoExcessFPPrecision;
  32   bool UnsafeFPMath;
  33   bool NoInfsFPMath;
  34   bool NoNaNsFPMath;
  35   bool HonorSignDependentRoundingFPMathOption;
  36   bool UseSoftFloat;
  37   FloatABI::ABIType FloatABIType;
  38   bool NoImplicitFloat;
  39   bool NoZerosInBSS;
  40   bool JITExceptionHandling;
  41   bool JITEmitDebugInfo;
  42   bool JITEmitDebugInfoToDisk;
  43   bool UnwindTablesMandatory;
  44   Reloc::Model RelocationModel;
  45   CodeModel::Model CMModel;
  46   bool GuaranteedTailCallOpt;
  47   unsigned StackAlignment;
  48   bool RealignStack;
  49   bool DisableJumpTables;
  50   bool StrongPHIElim;
  51   bool HasDivModLibcall;
  52   bool AsmVerbosityDefault(false);
  53 }
  54
  55 static cl::opt<bool, true>
  56 PrintCode("print-machineinstrs",
  57   cl::desc("Print generated machine code"),
  58   cl::location(PrintMachineCode), cl::init(false));
  59 static cl::opt<bool, true>
  60 DisableFPElim("disable-fp-elim",
  61   cl::desc("Disable frame pointer elimination optimization"),
  62   cl::location(NoFramePointerElim),
  63   cl::init(false));
  64 static cl::opt<bool, true>
  65 DisableFPElimNonLeaf("disable-non-leaf-fp-elim",
  66   cl::desc("Disable frame pointer elimination optimization for non-leaf funcs"),
  67   cl::location(NoFramePointerElimNonLeaf),
  68   cl::init(false));
  69 static cl::opt<bool, true>
  70 DisableExcessPrecision("disable-excess-fp-precision",
  71   cl::desc("Disable optimizations that may increase FP precision"),
  72   cl::location(NoExcessFPPrecision),
  73   cl::init(false));
  74 static cl::opt<bool, true>
  75 EnableFPMAD("enable-fp-mad",
  76   cl::desc("Enable less precise MAD instructions to be generated"),
  77   cl::location(LessPreciseFPMADOption),
  78   cl::init(false));
  79 static cl::opt<bool, true>
  80 EnableUnsafeFPMath("enable-unsafe-fp-math",
  81   cl::desc("Enable optimizations that may decrease FP precision"),
  82   cl::location(UnsafeFPMath),
  83   cl::init(false));
  84 static cl::opt<bool, true>
  85 EnableNoInfsFPMath("enable-no-infs-fp-math",
  86   cl::desc("Enable FP math optimizations that assume no +-Infs"),
  87   cl::location(NoInfsFPMath),
  88   cl::init(false));
  89 static cl::opt<bool, true>
  90 EnableNoNaNsFPMath("enable-no-nans-fp-math",
  91   cl::desc("Enable FP math optimizations that assume no NaNs"),
  92   cl::location(NoNaNsFPMath),
  93   cl::init(false));
  94 static cl::opt<bool, true>
  95 EnableHonorSignDependentRoundingFPMath("enable-sign-dependent-rounding-fp-math",
  96   cl::Hidden,
  97   cl::desc("Force codegen to assume rounding mode can change dynamically"),
  98   cl::location(HonorSignDependentRoundingFPMathOption),
  99   cl::init(false));
 100 static cl::opt<bool, true>
 101 GenerateSoftFloatCalls("soft-float",
 102   cl::desc("Generate software floating point library calls"),
 103   cl::location(UseSoftFloat),
 104   cl::init(false));
 105 static cl::opt<llvm::FloatABI::ABIType, true>
 106 FloatABIForCalls("float-abi",
 107   cl::desc("Choose float ABI type"),
 108   cl::location(FloatABIType),
 109   cl::init(FloatABI::Default),
 110   cl::values(
 111     clEnumValN(FloatABI::Default, "default",
 112                "Target default float ABI type"),
 113     clEnumValN(FloatABI::Soft, "soft",
 114                "Soft float ABI (implied by -soft-float)"),
 115     clEnumValN(FloatABI::Hard, "hard",
 116                "Hard float ABI (uses FP registers)"),
 117     clEnumValEnd));
 118 static cl::opt<bool, true>
 119 DontPlaceZerosInBSS("nozero-initialized-in-bss",
 120   cl::desc("Don't place zero-initialized symbols into bss section"),
 121   cl::location(NoZerosInBSS),
 122   cl::init(false));
 123 static cl::opt<bool, true>
 124 EnableJITExceptionHandling("jit-enable-eh",
 125   cl::desc("Emit exception handling information"),
 126   cl::location(JITExceptionHandling),
 127   cl::init(false));
 128 // In debug builds, make this default to true.
 129 #ifdef NDEBUG
 130 #define EMIT_DEBUG false
 131 #else
 132 #define EMIT_DEBUG true
 133 #endif
 134 static cl::opt<bool, true>
 135 EmitJitDebugInfo("jit-emit-debug",
 136   cl::desc("Emit debug information to debugger"),
 137   cl::location(JITEmitDebugInfo),
 138   cl::init(EMIT_DEBUG));
 139 #undef EMIT_DEBUG
 140 static cl::opt<bool, true>
 141 EmitJitDebugInfoToDisk("jit-emit-debug-to-disk",
 142   cl::Hidden,
 143   cl::desc("Emit debug info objfiles to disk"),
 144   cl::location(JITEmitDebugInfoToDisk),
 145   cl::init(false));
 146 static cl::opt<bool, true>
 147 EnableUnwindTables("unwind-tables",
 148   cl::desc("Generate unwinding tables for all functions"),
 149   cl::location(UnwindTablesMandatory),
 150   cl::init(false));
 151
 152 static cl::opt<llvm::Reloc::Model, true>
 153 DefRelocationModel("relocation-model",
 154   cl::desc("Choose relocation model"),
 155   cl::location(RelocationModel),
 156   cl::init(Reloc::Default),
 157   cl::values(
 158     clEnumValN(Reloc::Default, "default",
 159                "Target default relocation model"),
 160     clEnumValN(Reloc::Static, "static",
 161                "Non-relocatable code"),
 162     clEnumValN(Reloc::PIC_, "pic",
 163                "Fully relocatable, position independent code"),
 164     clEnumValN(Reloc::DynamicNoPIC, "dynamic-no-pic",
 165                "Relocatable external references, non-relocatable code"),
 166     clEnumValEnd));
 167 static cl::opt<llvm::CodeModel::Model, true>
 168 DefCodeModel("code-model",
 169   cl::desc("Choose code model"),
 170   cl::location(CMModel),
 171   cl::init(CodeModel::Default),
 172   cl::values(
 173     clEnumValN(CodeModel::Default, "default",
 174                "Target default code model"),
 175     clEnumValN(CodeModel::Small, "small",
 176                "Small code model"),
 177     clEnumValN(CodeModel::Kernel, "kernel",
 178                "Kernel code model"),
 179     clEnumValN(CodeModel::Medium, "medium",
 180                "Medium code model"),
 181     clEnumValN(CodeModel::Large, "large",
 182                "Large code model"),
 183     clEnumValEnd));
 184 static cl::opt<bool, true>
 185 EnableGuaranteedTailCallOpt("tailcallopt",
 186   cl::desc("Turn fastcc calls into tail calls by (potentially) changing ABI."),
 187   cl::location(GuaranteedTailCallOpt),
 188   cl::init(false));
 189 static cl::opt<unsigned, true>
 190 OverrideStackAlignment("stack-alignment",
 191   cl::desc("Override default stack alignment"),
 192   cl::location(StackAlignment),
 193   cl::init(0));
 194 static cl::opt<bool, true>
 195 EnableRealignStack("realign-stack",
 196   cl::desc("Realign stack if needed"),
 197   cl::location(RealignStack),
 198   cl::init(true));
 199 static cl::opt<bool, true>
 200 DisableSwitchTables(cl::Hidden, "disable-jump-tables",
 201   cl::desc("Do not generate jump tables."),
 202   cl::location(DisableJumpTables),
 203   cl::init(false));
 204 static cl::opt<bool, true>
 205 EnableStrongPHIElim(cl::Hidden, "strong-phi-elim",
 206   cl::desc("Use strong PHI elimination."),
 207   cl::location(StrongPHIElim),
 208   cl::init(false));
 209 static cl::opt<bool, true>
 210 UseDivMod("use-divmod-libcall",
 211   cl::desc("Use __{u}divmod libcalls for div / rem pairs"),
 212   cl::location(HasDivModLibcall),
 213   cl::init(false));
 214 static cl::opt<std::string>
 215 TrapFuncName("trap-func", cl::Hidden,
 216   cl::desc("Emit a call to trap function rather than a trap instruction"),
 217   cl::init(""));
 218 static cl::opt<bool>
 219 DataSections("fdata-sections",
 220   cl::desc("Emit data into separate sections"),
 221   cl::init(false));
 222 static cl::opt<bool>
 223 FunctionSections("ffunction-sections",
 224   cl::desc("Emit functions into separate sections"),
 225   cl::init(false));
 226 //---------------------------------------------------------------------------
 227 // TargetMachine Class
 228 //
 229
 230 TargetMachine::TargetMachine(const Target &T)
 231   : TheTarget(T), AsmInfo(0),
 232     MCRelaxAll(false),
 233     MCNoExecStack(false),
 234     MCSaveTempLabels(false),
 235     MCUseLoc(true) {
 236   // Typically it will be subtargets that will adjust FloatABIType from Default
 237   // to Soft or Hard.
 238   if (UseSoftFloat)
 239     FloatABIType = FloatABI::Soft;
 240 }
 241
 242 TargetMachine::~TargetMachine() {
 243   delete AsmInfo;
 244 }
 245
 246 /// getRelocationModel - Returns the code generation relocation model. The
 247 /// choices are static, PIC, and dynamic-no-pic, and target default.
 248 Reloc::Model TargetMachine::getRelocationModel() {
 249   return RelocationModel;
 250 }
 251
 252 /// setRelocationModel - Sets the code generation relocation model.
 253 void TargetMachine::setRelocationModel(Reloc::Model Model) {
 254   RelocationModel = Model;
 255 }
 256
 257 /// getCodeModel - Returns the code model. The choices are small, kernel,
 258 /// medium, large, and target default.
 259 CodeModel::Model TargetMachine::getCodeModel() {
 260   return CMModel;
 261 }
 262
 263 /// setCodeModel - Sets the code model.
 264 void TargetMachine::setCodeModel(CodeModel::Model Model) {
 265   CMModel = Model;
 266 }
 267
 268 bool TargetMachine::getAsmVerbosityDefault() {
 269   return AsmVerbosityDefault;
 270 }
 271
 272 void TargetMachine::setAsmVerbosityDefault(bool V) {
 273   AsmVerbosityDefault = V;
 274 }
 275
 276 bool TargetMachine::getFunctionSections() {
 277   return FunctionSections;
 278 }
 279
 280 bool TargetMachine::getDataSections() {
 281   return DataSections;
 282 }
 283
 284 void TargetMachine::setFunctionSections(bool V) {
 285   FunctionSections = V;
 286 }
 287
 288 void TargetMachine::setDataSections(bool V) {
 289   DataSections = V;
 290 }
 291
 292 namespace llvm {
 293   /// DisableFramePointerElim - This returns true if frame pointer elimination
 294   /// optimization should be disabled for the given machine function.
 295   bool DisableFramePointerElim(const MachineFunction &MF) {
 296     // Check to see if we should eliminate non-leaf frame pointers and then
 297     // check to see if we should eliminate all frame pointers.
 298     if (NoFramePointerElimNonLeaf && !NoFramePointerElim) {
 299       const MachineFrameInfo *MFI = MF.getFrameInfo();
 300       return MFI->hasCalls();
 301     }
 302
 303     return NoFramePointerElim;
 304   }
 305
 306   /// LessPreciseFPMAD - This flag return true when -enable-fp-mad option
 307   /// is specified on the command line.  When this flag is off(default), the
 308   /// code generator is not allowed to generate mad (multiply add) if the
 309   /// result is "less precise" than doing those operations individually.
 310   bool LessPreciseFPMAD() { return UnsafeFPMath || LessPreciseFPMADOption; }
 311
 312   /// HonorSignDependentRoundingFPMath - Return true if the codegen must assume
 313   /// that the rounding mode of the FPU can change from its default.
 314   bool HonorSignDependentRoundingFPMath() {
 315     return !UnsafeFPMath && HonorSignDependentRoundingFPMathOption;
 316   }
 317
 318   /// getTrapFunctionName - If this returns a non-empty string, this means isel
 319   /// should lower Intrinsic::trap to a call to the specified function name
 320   /// instead of an ISD::TRAP node.
 321   StringRef getTrapFunctionName() {
 322     return TrapFuncName;
 323   }
 324 }