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/Target/TargetAsmInfo.h"
  15 #include "llvm/Target/TargetMachine.h"
  16 #include "llvm/Target/TargetOptions.h"
  17 #include "llvm/Support/CommandLine.h"
  18 using namespace llvm;
  19
  20 //---------------------------------------------------------------------------
  21 // Command-line options that tend to be useful on more than one back-end.
  22 //
  23
  24 namespace llvm {
  25   bool LessPreciseFPMADOption;
  26   bool PrintMachineCode;
  27   bool NoFramePointerElim;
  28   bool NoExcessFPPrecision;
  29   bool UnsafeFPMath;
  30   bool FiniteOnlyFPMathOption;
  31   bool HonorSignDependentRoundingFPMathOption;
  32   bool UseSoftFloat;
  33   bool NoImplicitFloat;
  34   bool NoZerosInBSS;
  35   bool ExceptionHandling;
  36   bool UnwindTablesMandatory;
  37   Reloc::Model RelocationModel;
  38   CodeModel::Model CMModel;
  39   bool PerformTailCallOpt;
  40   unsigned StackAlignment;
  41   bool RealignStack;
  42   bool DisableJumpTables;
  43   bool StrongPHIElim;
  44   bool DisableRedZone;
  45   bool AsmVerbosityDefault(false);
  46 }
  47
  48 static cl::opt<bool, true>
  49 PrintCode("print-machineinstrs",
  50   cl::desc("Print generated machine code"),
  51   cl::location(PrintMachineCode), cl::init(false));
  52 static cl::opt<bool, true>
  53 DisableFPElim("disable-fp-elim",
  54   cl::desc("Disable frame pointer elimination optimization"),
  55   cl::location(NoFramePointerElim),
  56   cl::init(false));
  57 static cl::opt<bool, true>
  58 DisableExcessPrecision("disable-excess-fp-precision",
  59   cl::desc("Disable optimizations that may increase FP precision"),
  60   cl::location(NoExcessFPPrecision),
  61   cl::init(false));
  62 static cl::opt<bool, true>
  63 EnableFPMAD("enable-fp-mad",
  64   cl::desc("Enable less precise MAD instructions to be generated"),
  65   cl::location(LessPreciseFPMADOption),
  66   cl::init(false));
  67 static cl::opt<bool, true>
  68 EnableUnsafeFPMath("enable-unsafe-fp-math",
  69   cl::desc("Enable optimizations that may decrease FP precision"),
  70   cl::location(UnsafeFPMath),
  71   cl::init(false));
  72 static cl::opt<bool, true>
  73 EnableFiniteOnlyFPMath("enable-finite-only-fp-math",
  74   cl::desc("Enable optimizations that assumes non- NaNs / +-Infs"),
  75   cl::location(FiniteOnlyFPMathOption),
  76   cl::init(false));
  77 static cl::opt<bool, true>
  78 EnableHonorSignDependentRoundingFPMath("enable-sign-dependent-rounding-fp-math",
  79   cl::Hidden,
  80   cl::desc("Force codegen to assume rounding mode can change dynamically"),
  81   cl::location(HonorSignDependentRoundingFPMathOption),
  82   cl::init(false));
  83 static cl::opt<bool, true>
  84 GenerateSoftFloatCalls("soft-float",
  85   cl::desc("Generate software floating point library calls"),
  86   cl::location(UseSoftFloat),
  87   cl::init(false));
  88 static cl::opt<bool, true>
  89 GenerateNoImplicitFloats("no-implicit-float",
  90   cl::desc("Don't generate implicit floating point instructions (x86-only)"),
  91   cl::location(NoImplicitFloat),
  92   cl::init(false));
  93 static cl::opt<bool, true>
  94 DontPlaceZerosInBSS("nozero-initialized-in-bss",
  95   cl::desc("Don't place zero-initialized symbols into bss section"),
  96   cl::location(NoZerosInBSS),
  97   cl::init(false));
  98 static cl::opt<bool, true>
  99 EnableExceptionHandling("enable-eh",
 100   cl::desc("Emit DWARF exception handling (default if target supports)"),
 101   cl::location(ExceptionHandling),
 102   cl::init(false));
 103 static cl::opt<bool, true>
 104 EnableUnwindTables("unwind-tables",
 105   cl::desc("Generate unwinding tables for all functions"),
 106   cl::location(UnwindTablesMandatory),
 107   cl::init(false));
 108
 109 static cl::opt<llvm::Reloc::Model, true>
 110 DefRelocationModel("relocation-model",
 111   cl::desc("Choose relocation model"),
 112   cl::location(RelocationModel),
 113   cl::init(Reloc::Default),
 114   cl::values(
 115     clEnumValN(Reloc::Default, "default",
 116                "Target default relocation model"),
 117     clEnumValN(Reloc::Static, "static",
 118                "Non-relocatable code"),
 119     clEnumValN(Reloc::PIC_, "pic",
 120                "Fully relocatable, position independent code"),
 121     clEnumValN(Reloc::DynamicNoPIC, "dynamic-no-pic",
 122                "Relocatable external references, non-relocatable code"),
 123     clEnumValEnd));
 124 static cl::opt<llvm::CodeModel::Model, true>
 125 DefCodeModel("code-model",
 126   cl::desc("Choose code model"),
 127   cl::location(CMModel),
 128   cl::init(CodeModel::Default),
 129   cl::values(
 130     clEnumValN(CodeModel::Default, "default",
 131                "Target default code model"),
 132     clEnumValN(CodeModel::Small, "small",
 133                "Small code model"),
 134     clEnumValN(CodeModel::Kernel, "kernel",
 135                "Kernel code model"),
 136     clEnumValN(CodeModel::Medium, "medium",
 137                "Medium code model"),
 138     clEnumValN(CodeModel::Large, "large",
 139                "Large code model"),
 140     clEnumValEnd));
 141 static cl::opt<bool, true>
 142 EnablePerformTailCallOpt("tailcallopt",
 143   cl::desc("Turn on tail call optimization."),
 144   cl::location(PerformTailCallOpt),
 145   cl::init(false));
 146 static cl::opt<unsigned, true>
 147 OverrideStackAlignment("stack-alignment",
 148   cl::desc("Override default stack alignment"),
 149   cl::location(StackAlignment),
 150   cl::init(0));
 151 static cl::opt<bool, true>
 152 EnableRealignStack("realign-stack",
 153   cl::desc("Realign stack if needed"),
 154   cl::location(RealignStack),
 155   cl::init(true));
 156 static cl::opt<bool, true>
 157 DisableSwitchTables(cl::Hidden, "disable-jump-tables",
 158   cl::desc("Do not generate jump tables."),
 159   cl::location(DisableJumpTables),
 160   cl::init(false));
 161 static cl::opt<bool, true>
 162 EnableStrongPHIElim(cl::Hidden, "strong-phi-elim",
 163   cl::desc("Use strong PHI elimination."),
 164   cl::location(StrongPHIElim),
 165   cl::init(false));
 166 static cl::opt<bool, true>
 167 DisableRedZoneOption("disable-red-zone",
 168   cl::desc("Do not emit code that uses the red zone."),
 169   cl::location(DisableRedZone),
 170   cl::init(false));
 171
 172 //---------------------------------------------------------------------------
 173 // TargetMachine Class
 174 //
 175
 176 TargetMachine::~TargetMachine() {
 177   delete AsmInfo;
 178 }
 179
 180 /// getRelocationModel - Returns the code generation relocation model. The
 181 /// choices are static, PIC, and dynamic-no-pic, and target default.
 182 Reloc::Model TargetMachine::getRelocationModel() {
 183   return RelocationModel;
 184 }
 185
 186 /// setRelocationModel - Sets the code generation relocation model.
 187 void TargetMachine::setRelocationModel(Reloc::Model Model) {
 188   RelocationModel = Model;
 189 }
 190
 191 /// getCodeModel - Returns the code model. The choices are small, kernel,
 192 /// medium, large, and target default.
 193 CodeModel::Model TargetMachine::getCodeModel() {
 194   return CMModel;
 195 }
 196
 197 /// setCodeModel - Sets the code model.
 198 void TargetMachine::setCodeModel(CodeModel::Model Model) {
 199   CMModel = Model;
 200 }
 201
 202 bool TargetMachine::getAsmVerbosityDefault() {
 203   return AsmVerbosityDefault;
 204 }
 205
 206 void TargetMachine::setAsmVerbosityDefault(bool V) {
 207   AsmVerbosityDefault = V;
 208 }
 209
 210 namespace llvm {
 211   /// LessPreciseFPMAD - This flag return true when -enable-fp-mad option
 212   /// is specified on the command line.  When this flag is off(default), the
 213   /// code generator is not allowed to generate mad (multiply add) if the
 214   /// result is "less precise" than doing those operations individually.
 215   bool LessPreciseFPMAD() { return UnsafeFPMath || LessPreciseFPMADOption; }
 216
 217   /// FiniteOnlyFPMath - This returns true when the -enable-finite-only-fp-math
 218   /// option is specified on the command line. If this returns false (default),
 219   /// the code generator is not allowed to assume that FP arithmetic arguments
 220   /// and results are never NaNs or +-Infs.
 221   bool FiniteOnlyFPMath() { return UnsafeFPMath || FiniteOnlyFPMathOption; }
 222
 223   /// HonorSignDependentRoundingFPMath - Return true if the codegen must assume
 224   /// that the rounding mode of the FPU can change from its default.
 225   bool HonorSignDependentRoundingFPMath() {
 226     return !UnsafeFPMath && HonorSignDependentRoundingFPMathOption;
 227   }
 228 }
 229