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/MC/MCAsmInfo.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   FloatABI::ABIType FloatABIType;
  34   bool NoImplicitFloat;
  35   bool NoZerosInBSS;
  36   bool DwarfExceptionHandling;
  37   bool SjLjExceptionHandling;
  38   bool UnwindTablesMandatory;
  39   Reloc::Model RelocationModel;
  40   CodeModel::Model CMModel;
  41   bool PerformTailCallOpt;
  42   unsigned StackAlignment;
  43   bool RealignStack;
  44   bool DisableJumpTables;
  45   bool StrongPHIElim;
  46   bool AsmVerbosityDefault(false);
  47 }
  48
  49 static cl::opt<bool, true>
  50 PrintCode("print-machineinstrs",
  51   cl::desc("Print generated machine code"),
  52   cl::location(PrintMachineCode), cl::init(false));
  53 static cl::opt<bool, true>
  54 DisableFPElim("disable-fp-elim",
  55   cl::desc("Disable frame pointer elimination optimization"),
  56   cl::location(NoFramePointerElim),
  57   cl::init(false));
  58 static cl::opt<bool, true>
  59 DisableExcessPrecision("disable-excess-fp-precision",
  60   cl::desc("Disable optimizations that may increase FP precision"),
  61   cl::location(NoExcessFPPrecision),
  62   cl::init(false));
  63 static cl::opt<bool, true>
  64 EnableFPMAD("enable-fp-mad",
  65   cl::desc("Enable less precise MAD instructions to be generated"),
  66   cl::location(LessPreciseFPMADOption),
  67   cl::init(false));
  68 static cl::opt<bool, true>
  69 EnableUnsafeFPMath("enable-unsafe-fp-math",
  70   cl::desc("Enable optimizations that may decrease FP precision"),
  71   cl::location(UnsafeFPMath),
  72   cl::init(false));
  73 static cl::opt<bool, true>
  74 EnableFiniteOnlyFPMath("enable-finite-only-fp-math",
  75   cl::desc("Enable optimizations that assumes non- NaNs / +-Infs"),
  76   cl::location(FiniteOnlyFPMathOption),
  77   cl::init(false));
  78 static cl::opt<bool, true>
  79 EnableHonorSignDependentRoundingFPMath("enable-sign-dependent-rounding-fp-math",
  80   cl::Hidden,
  81   cl::desc("Force codegen to assume rounding mode can change dynamically"),
  82   cl::location(HonorSignDependentRoundingFPMathOption),
  83   cl::init(false));
  84 static cl::opt<bool, true>
  85 GenerateSoftFloatCalls("soft-float",
  86   cl::desc("Generate software floating point library calls"),
  87   cl::location(UseSoftFloat),
  88   cl::init(false));
  89 static cl::opt<llvm::FloatABI::ABIType, true>
  90 FloatABIForCalls("float-abi",
  91   cl::desc("Choose float ABI type"),
  92   cl::location(FloatABIType),
  93   cl::init(FloatABI::Default),
  94   cl::values(
  95     clEnumValN(FloatABI::Default, "default",
  96                "Target default float ABI type"),
  97     clEnumValN(FloatABI::Soft, "soft",
  98                "Soft float ABI (implied by -soft-float)"),
  99     clEnumValN(FloatABI::Hard, "hard",
 100                "Hard float ABI (uses FP registers)"),
 101     clEnumValEnd));
 102 static cl::opt<bool, true>
 103 DontPlaceZerosInBSS("nozero-initialized-in-bss",
 104   cl::desc("Don't place zero-initialized symbols into bss section"),
 105   cl::location(NoZerosInBSS),
 106   cl::init(false));
 107 static cl::opt<bool, true>
 108 EnableDwarfExceptionHandling("enable-eh",
 109   cl::desc("Emit DWARF exception handling (default if target supports)"),
 110   cl::location(DwarfExceptionHandling),
 111   cl::init(false));
 112 static cl::opt<bool, true>
 113 EnableSjLjExceptionHandling("enable-sjlj-eh",
 114   cl::desc("Emit SJLJ exception handling (default if target supports)"),
 115   cl::location(SjLjExceptionHandling),
 116   cl::init(false));
 117 static cl::opt<bool, true>
 118 EnableUnwindTables("unwind-tables",
 119   cl::desc("Generate unwinding tables for all functions"),
 120   cl::location(UnwindTablesMandatory),
 121   cl::init(false));
 122
 123 static cl::opt<llvm::Reloc::Model, true>
 124 DefRelocationModel("relocation-model",
 125   cl::desc("Choose relocation model"),
 126   cl::location(RelocationModel),
 127   cl::init(Reloc::Default),
 128   cl::values(
 129     clEnumValN(Reloc::Default, "default",
 130                "Target default relocation model"),
 131     clEnumValN(Reloc::Static, "static",
 132                "Non-relocatable code"),
 133     clEnumValN(Reloc::PIC_, "pic",
 134                "Fully relocatable, position independent code"),
 135     clEnumValN(Reloc::DynamicNoPIC, "dynamic-no-pic",
 136                "Relocatable external references, non-relocatable code"),
 137     clEnumValEnd));
 138 static cl::opt<llvm::CodeModel::Model, true>
 139 DefCodeModel("code-model",
 140   cl::desc("Choose code model"),
 141   cl::location(CMModel),
 142   cl::init(CodeModel::Default),
 143   cl::values(
 144     clEnumValN(CodeModel::Default, "default",
 145                "Target default code model"),
 146     clEnumValN(CodeModel::Small, "small",
 147                "Small code model"),
 148     clEnumValN(CodeModel::Kernel, "kernel",
 149                "Kernel code model"),
 150     clEnumValN(CodeModel::Medium, "medium",
 151                "Medium code model"),
 152     clEnumValN(CodeModel::Large, "large",
 153                "Large code model"),
 154     clEnumValEnd));
 155 static cl::opt<bool, true>
 156 EnablePerformTailCallOpt("tailcallopt",
 157   cl::desc("Turn on tail call optimization."),
 158   cl::location(PerformTailCallOpt),
 159   cl::init(false));
 160 static cl::opt<unsigned, true>
 161 OverrideStackAlignment("stack-alignment",
 162   cl::desc("Override default stack alignment"),
 163   cl::location(StackAlignment),
 164   cl::init(0));
 165 static cl::opt<bool, true>
 166 EnableRealignStack("realign-stack",
 167   cl::desc("Realign stack if needed"),
 168   cl::location(RealignStack),
 169   cl::init(true));
 170 static cl::opt<bool, true>
 171 DisableSwitchTables(cl::Hidden, "disable-jump-tables",
 172   cl::desc("Do not generate jump tables."),
 173   cl::location(DisableJumpTables),
 174   cl::init(false));
 175 static cl::opt<bool, true>
 176 EnableStrongPHIElim(cl::Hidden, "strong-phi-elim",
 177   cl::desc("Use strong PHI elimination."),
 178   cl::location(StrongPHIElim),
 179   cl::init(false));
 180
 181 //---------------------------------------------------------------------------
 182 // TargetMachine Class
 183 //
 184
 185 TargetMachine::TargetMachine(const Target &T)
 186   : TheTarget(T), AsmInfo(0) {
 187   // Typically it will be subtargets that will adjust FloatABIType from Default
 188   // to Soft or Hard.
 189   if (UseSoftFloat)
 190     FloatABIType = FloatABI::Soft;
 191 }
 192
 193 TargetMachine::~TargetMachine() {
 194   delete AsmInfo;
 195 }
 196
 197 /// getRelocationModel - Returns the code generation relocation model. The
 198 /// choices are static, PIC, and dynamic-no-pic, and target default.
 199 Reloc::Model TargetMachine::getRelocationModel() {
 200   return RelocationModel;
 201 }
 202
 203 /// setRelocationModel - Sets the code generation relocation model.
 204 void TargetMachine::setRelocationModel(Reloc::Model Model) {
 205   RelocationModel = Model;
 206 }
 207
 208 /// getCodeModel - Returns the code model. The choices are small, kernel,
 209 /// medium, large, and target default.
 210 CodeModel::Model TargetMachine::getCodeModel() {
 211   return CMModel;
 212 }
 213
 214 /// setCodeModel - Sets the code model.
 215 void TargetMachine::setCodeModel(CodeModel::Model Model) {
 216   CMModel = Model;
 217 }
 218
 219 bool TargetMachine::getAsmVerbosityDefault() {
 220   return AsmVerbosityDefault;
 221 }
 222
 223 void TargetMachine::setAsmVerbosityDefault(bool V) {
 224   AsmVerbosityDefault = V;
 225 }
 226
 227 namespace llvm {
 228   /// LessPreciseFPMAD - This flag return true when -enable-fp-mad option
 229   /// is specified on the command line.  When this flag is off(default), the
 230   /// code generator is not allowed to generate mad (multiply add) if the
 231   /// result is "less precise" than doing those operations individually.
 232   bool LessPreciseFPMAD() { return UnsafeFPMath || LessPreciseFPMADOption; }
 233
 234   /// FiniteOnlyFPMath - This returns true when the -enable-finite-only-fp-math
 235   /// option is specified on the command line. If this returns false (default),
 236   /// the code generator is not allowed to assume that FP arithmetic arguments
 237   /// and results are never NaNs or +-Infs.
 238   bool FiniteOnlyFPMath() { return UnsafeFPMath || FiniteOnlyFPMathOption; }
 239
 240   /// HonorSignDependentRoundingFPMath - Return true if the codegen must assume
 241   /// that the rounding mode of the FPU can change from its default.
 242   bool HonorSignDependentRoundingFPMath() {
 243     return !UnsafeFPMath && HonorSignDependentRoundingFPMathOption;
 244   }
 245 }
 246