1 //===-- TargetMachine.cpp - General Target Information ---------------------==//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file describes the general parts of a Target machine.
12 //===----------------------------------------------------------------------===//
14 #include "llvm/MC/MCAsmInfo.h"
15 #include "llvm/Target/TargetMachine.h"
16 #include "llvm/Target/TargetOptions.h"
17 #include "llvm/Support/CommandLine.h"
20 //---------------------------------------------------------------------------
21 // Command-line options that tend to be useful on more than one back-end.
25 bool LessPreciseFPMADOption;
26 bool PrintMachineCode;
27 bool NoFramePointerElim;
28 bool NoExcessFPPrecision;
30 bool FiniteOnlyFPMathOption;
31 bool HonorSignDependentRoundingFPMathOption;
33 FloatABI::ABIType FloatABIType;
36 bool DwarfExceptionHandling;
37 bool SjLjExceptionHandling;
38 bool JITEmitDebugInfo;
39 bool JITEmitDebugInfoToDisk;
40 bool UnwindTablesMandatory;
41 Reloc::Model RelocationModel;
42 CodeModel::Model CMModel;
43 bool PerformTailCallOpt;
44 unsigned StackAlignment;
46 bool DisableJumpTables;
48 bool AsmVerbosityDefault(false);
51 static cl::opt<bool, true>
52 PrintCode("print-machineinstrs",
53 cl::desc("Print generated machine code"),
54 cl::location(PrintMachineCode), cl::init(false));
55 static cl::opt<bool, true>
56 DisableFPElim("disable-fp-elim",
57 cl::desc("Disable frame pointer elimination optimization"),
58 cl::location(NoFramePointerElim),
60 static cl::opt<bool, true>
61 DisableExcessPrecision("disable-excess-fp-precision",
62 cl::desc("Disable optimizations that may increase FP precision"),
63 cl::location(NoExcessFPPrecision),
65 static cl::opt<bool, true>
66 EnableFPMAD("enable-fp-mad",
67 cl::desc("Enable less precise MAD instructions to be generated"),
68 cl::location(LessPreciseFPMADOption),
70 static cl::opt<bool, true>
71 EnableUnsafeFPMath("enable-unsafe-fp-math",
72 cl::desc("Enable optimizations that may decrease FP precision"),
73 cl::location(UnsafeFPMath),
75 static cl::opt<bool, true>
76 EnableFiniteOnlyFPMath("enable-finite-only-fp-math",
77 cl::desc("Enable optimizations that assumes non- NaNs / +-Infs"),
78 cl::location(FiniteOnlyFPMathOption),
80 static cl::opt<bool, true>
81 EnableHonorSignDependentRoundingFPMath("enable-sign-dependent-rounding-fp-math",
83 cl::desc("Force codegen to assume rounding mode can change dynamically"),
84 cl::location(HonorSignDependentRoundingFPMathOption),
86 static cl::opt<bool, true>
87 GenerateSoftFloatCalls("soft-float",
88 cl::desc("Generate software floating point library calls"),
89 cl::location(UseSoftFloat),
91 static cl::opt<llvm::FloatABI::ABIType, true>
92 FloatABIForCalls("float-abi",
93 cl::desc("Choose float ABI type"),
94 cl::location(FloatABIType),
95 cl::init(FloatABI::Default),
97 clEnumValN(FloatABI::Default, "default",
98 "Target default float ABI type"),
99 clEnumValN(FloatABI::Soft, "soft",
100 "Soft float ABI (implied by -soft-float)"),
101 clEnumValN(FloatABI::Hard, "hard",
102 "Hard float ABI (uses FP registers)"),
104 static cl::opt<bool, true>
105 DontPlaceZerosInBSS("nozero-initialized-in-bss",
106 cl::desc("Don't place zero-initialized symbols into bss section"),
107 cl::location(NoZerosInBSS),
109 static cl::opt<bool, true>
110 EnableDwarfExceptionHandling("enable-eh",
111 cl::desc("Emit DWARF exception handling (default if target supports)"),
112 cl::location(DwarfExceptionHandling),
114 static cl::opt<bool, true>
115 EnableSjLjExceptionHandling("enable-sjlj-eh",
116 cl::desc("Emit SJLJ exception handling (default if target supports)"),
117 cl::location(SjLjExceptionHandling),
119 // In debug builds, make this default to true.
121 #define EMIT_DEBUG false
123 #define EMIT_DEBUG true
125 static cl::opt<bool, true>
126 EmitJitDebugInfo("jit-emit-debug",
127 cl::desc("Emit debug information to debugger"),
128 cl::location(JITEmitDebugInfo),
129 cl::init(EMIT_DEBUG));
131 static cl::opt<bool, true>
132 EmitJitDebugInfoToDisk("jit-emit-debug-to-disk",
134 cl::desc("Emit debug info objfiles to disk"),
135 cl::location(JITEmitDebugInfoToDisk),
137 static cl::opt<bool, true>
138 EnableUnwindTables("unwind-tables",
139 cl::desc("Generate unwinding tables for all functions"),
140 cl::location(UnwindTablesMandatory),
143 static cl::opt<llvm::Reloc::Model, true>
144 DefRelocationModel("relocation-model",
145 cl::desc("Choose relocation model"),
146 cl::location(RelocationModel),
147 cl::init(Reloc::Default),
149 clEnumValN(Reloc::Default, "default",
150 "Target default relocation model"),
151 clEnumValN(Reloc::Static, "static",
152 "Non-relocatable code"),
153 clEnumValN(Reloc::PIC_, "pic",
154 "Fully relocatable, position independent code"),
155 clEnumValN(Reloc::DynamicNoPIC, "dynamic-no-pic",
156 "Relocatable external references, non-relocatable code"),
158 static cl::opt<llvm::CodeModel::Model, true>
159 DefCodeModel("code-model",
160 cl::desc("Choose code model"),
161 cl::location(CMModel),
162 cl::init(CodeModel::Default),
164 clEnumValN(CodeModel::Default, "default",
165 "Target default code model"),
166 clEnumValN(CodeModel::Small, "small",
168 clEnumValN(CodeModel::Kernel, "kernel",
169 "Kernel code model"),
170 clEnumValN(CodeModel::Medium, "medium",
171 "Medium code model"),
172 clEnumValN(CodeModel::Large, "large",
175 static cl::opt<bool, true>
176 EnablePerformTailCallOpt("tailcallopt",
177 cl::desc("Turn on tail call optimization."),
178 cl::location(PerformTailCallOpt),
180 static cl::opt<unsigned, true>
181 OverrideStackAlignment("stack-alignment",
182 cl::desc("Override default stack alignment"),
183 cl::location(StackAlignment),
185 static cl::opt<bool, true>
186 EnableRealignStack("realign-stack",
187 cl::desc("Realign stack if needed"),
188 cl::location(RealignStack),
190 static cl::opt<bool, true>
191 DisableSwitchTables(cl::Hidden, "disable-jump-tables",
192 cl::desc("Do not generate jump tables."),
193 cl::location(DisableJumpTables),
195 static cl::opt<bool, true>
196 EnableStrongPHIElim(cl::Hidden, "strong-phi-elim",
197 cl::desc("Use strong PHI elimination."),
198 cl::location(StrongPHIElim),
201 //---------------------------------------------------------------------------
202 // TargetMachine Class
205 TargetMachine::TargetMachine(const Target &T)
206 : TheTarget(T), AsmInfo(0) {
207 // Typically it will be subtargets that will adjust FloatABIType from Default
210 FloatABIType = FloatABI::Soft;
213 TargetMachine::~TargetMachine() {
217 /// getRelocationModel - Returns the code generation relocation model. The
218 /// choices are static, PIC, and dynamic-no-pic, and target default.
219 Reloc::Model TargetMachine::getRelocationModel() {
220 return RelocationModel;
223 /// setRelocationModel - Sets the code generation relocation model.
224 void TargetMachine::setRelocationModel(Reloc::Model Model) {
225 RelocationModel = Model;
228 /// getCodeModel - Returns the code model. The choices are small, kernel,
229 /// medium, large, and target default.
230 CodeModel::Model TargetMachine::getCodeModel() {
234 /// setCodeModel - Sets the code model.
235 void TargetMachine::setCodeModel(CodeModel::Model Model) {
239 bool TargetMachine::getAsmVerbosityDefault() {
240 return AsmVerbosityDefault;
243 void TargetMachine::setAsmVerbosityDefault(bool V) {
244 AsmVerbosityDefault = V;
248 /// LessPreciseFPMAD - This flag return true when -enable-fp-mad option
249 /// is specified on the command line. When this flag is off(default), the
250 /// code generator is not allowed to generate mad (multiply add) if the
251 /// result is "less precise" than doing those operations individually.
252 bool LessPreciseFPMAD() { return UnsafeFPMath || LessPreciseFPMADOption; }
254 /// FiniteOnlyFPMath - This returns true when the -enable-finite-only-fp-math
255 /// option is specified on the command line. If this returns false (default),
256 /// the code generator is not allowed to assume that FP arithmetic arguments
257 /// and results are never NaNs or +-Infs.
258 bool FiniteOnlyFPMath() { return UnsafeFPMath || FiniteOnlyFPMathOption; }
260 /// HonorSignDependentRoundingFPMath - Return true if the codegen must assume
261 /// that the rounding mode of the FPU can change from its default.
262 bool HonorSignDependentRoundingFPMath() {
263 return !UnsafeFPMath && HonorSignDependentRoundingFPMathOption;