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