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/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"
22 //---------------------------------------------------------------------------
23 // Command-line options that tend to be useful on more than one back-end.
27 bool LessPreciseFPMADOption;
28 bool PrintMachineCode;
29 bool NoFramePointerElim;
30 bool NoFramePointerElimNonLeaf;
31 bool NoExcessFPPrecision;
35 bool HonorSignDependentRoundingFPMathOption;
37 FloatABI::ABIType FloatABIType;
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;
49 bool DisableJumpTables;
51 bool AsmVerbosityDefault(false);
54 static cl::opt<bool, true>
55 PrintCode("print-machineinstrs",
56 cl::desc("Print generated machine code"),
57 cl::location(PrintMachineCode), cl::init(false));
58 static cl::opt<bool, true>
59 DisableFPElim("disable-fp-elim",
60 cl::desc("Disable frame pointer elimination optimization"),
61 cl::location(NoFramePointerElim),
63 static cl::opt<bool, true>
64 DisableFPElimNonLeaf("disable-non-leaf-fp-elim",
65 cl::desc("Disable frame pointer elimination optimization for non-leaf funcs"),
66 cl::location(NoFramePointerElimNonLeaf),
68 static cl::opt<bool, true>
69 DisableExcessPrecision("disable-excess-fp-precision",
70 cl::desc("Disable optimizations that may increase FP precision"),
71 cl::location(NoExcessFPPrecision),
73 static cl::opt<bool, true>
74 EnableFPMAD("enable-fp-mad",
75 cl::desc("Enable less precise MAD instructions to be generated"),
76 cl::location(LessPreciseFPMADOption),
78 static cl::opt<bool, true>
79 EnableUnsafeFPMath("enable-unsafe-fp-math",
80 cl::desc("Enable optimizations that may decrease FP precision"),
81 cl::location(UnsafeFPMath),
83 static cl::opt<bool, true>
84 EnableNoInfsFPMath("enable-no-infs-fp-math",
85 cl::desc("Enable FP math optimizations that assume no +-Infs"),
86 cl::location(NoInfsFPMath),
88 static cl::opt<bool, true>
89 EnableNoNaNsFPMath("enable-no-nans-fp-math",
90 cl::desc("Enable FP math optimizations that assume no NaNs"),
91 cl::location(NoNaNsFPMath),
93 static cl::opt<bool, true>
94 EnableHonorSignDependentRoundingFPMath("enable-sign-dependent-rounding-fp-math",
96 cl::desc("Force codegen to assume rounding mode can change dynamically"),
97 cl::location(HonorSignDependentRoundingFPMathOption),
99 static cl::opt<bool, true>
100 GenerateSoftFloatCalls("soft-float",
101 cl::desc("Generate software floating point library calls"),
102 cl::location(UseSoftFloat),
104 static cl::opt<llvm::FloatABI::ABIType, true>
105 FloatABIForCalls("float-abi",
106 cl::desc("Choose float ABI type"),
107 cl::location(FloatABIType),
108 cl::init(FloatABI::Default),
110 clEnumValN(FloatABI::Default, "default",
111 "Target default float ABI type"),
112 clEnumValN(FloatABI::Soft, "soft",
113 "Soft float ABI (implied by -soft-float)"),
114 clEnumValN(FloatABI::Hard, "hard",
115 "Hard float ABI (uses FP registers)"),
117 static cl::opt<bool, true>
118 DontPlaceZerosInBSS("nozero-initialized-in-bss",
119 cl::desc("Don't place zero-initialized symbols into bss section"),
120 cl::location(NoZerosInBSS),
122 static cl::opt<bool, true>
123 EnableJITExceptionHandling("jit-enable-eh",
124 cl::desc("Emit exception handling information"),
125 cl::location(JITExceptionHandling),
127 // In debug builds, make this default to true.
129 #define EMIT_DEBUG false
131 #define EMIT_DEBUG true
133 static cl::opt<bool, true>
134 EmitJitDebugInfo("jit-emit-debug",
135 cl::desc("Emit debug information to debugger"),
136 cl::location(JITEmitDebugInfo),
137 cl::init(EMIT_DEBUG));
139 static cl::opt<bool, true>
140 EmitJitDebugInfoToDisk("jit-emit-debug-to-disk",
142 cl::desc("Emit debug info objfiles to disk"),
143 cl::location(JITEmitDebugInfoToDisk),
145 static cl::opt<bool, true>
146 EnableUnwindTables("unwind-tables",
147 cl::desc("Generate unwinding tables for all functions"),
148 cl::location(UnwindTablesMandatory),
151 static cl::opt<llvm::Reloc::Model, true>
152 DefRelocationModel("relocation-model",
153 cl::desc("Choose relocation model"),
154 cl::location(RelocationModel),
155 cl::init(Reloc::Default),
157 clEnumValN(Reloc::Default, "default",
158 "Target default relocation model"),
159 clEnumValN(Reloc::Static, "static",
160 "Non-relocatable code"),
161 clEnumValN(Reloc::PIC_, "pic",
162 "Fully relocatable, position independent code"),
163 clEnumValN(Reloc::DynamicNoPIC, "dynamic-no-pic",
164 "Relocatable external references, non-relocatable code"),
166 static cl::opt<llvm::CodeModel::Model, true>
167 DefCodeModel("code-model",
168 cl::desc("Choose code model"),
169 cl::location(CMModel),
170 cl::init(CodeModel::Default),
172 clEnumValN(CodeModel::Default, "default",
173 "Target default code model"),
174 clEnumValN(CodeModel::Small, "small",
176 clEnumValN(CodeModel::Kernel, "kernel",
177 "Kernel code model"),
178 clEnumValN(CodeModel::Medium, "medium",
179 "Medium code model"),
180 clEnumValN(CodeModel::Large, "large",
183 static cl::opt<bool, true>
184 EnableGuaranteedTailCallOpt("tailcallopt",
185 cl::desc("Turn fastcc calls into tail calls by (potentially) changing ABI."),
186 cl::location(GuaranteedTailCallOpt),
188 static cl::opt<unsigned, true>
189 OverrideStackAlignment("stack-alignment",
190 cl::desc("Override default stack alignment"),
191 cl::location(StackAlignment),
193 static cl::opt<bool, true>
194 EnableRealignStack("realign-stack",
195 cl::desc("Realign stack if needed"),
196 cl::location(RealignStack),
198 static cl::opt<bool, true>
199 DisableSwitchTables(cl::Hidden, "disable-jump-tables",
200 cl::desc("Do not generate jump tables."),
201 cl::location(DisableJumpTables),
203 static cl::opt<bool, true>
204 EnableStrongPHIElim(cl::Hidden, "strong-phi-elim",
205 cl::desc("Use strong PHI elimination."),
206 cl::location(StrongPHIElim),
209 DataSections("fdata-sections",
210 cl::desc("Emit data into separate sections"),
213 FunctionSections("ffunction-sections",
214 cl::desc("Emit functions into separate sections"),
216 //---------------------------------------------------------------------------
217 // TargetMachine Class
220 TargetMachine::TargetMachine(const Target &T)
221 : TheTarget(T), AsmInfo(0),
223 // Typically it will be subtargets that will adjust FloatABIType from Default
226 FloatABIType = FloatABI::Soft;
229 TargetMachine::~TargetMachine() {
233 /// getRelocationModel - Returns the code generation relocation model. The
234 /// choices are static, PIC, and dynamic-no-pic, and target default.
235 Reloc::Model TargetMachine::getRelocationModel() {
236 return RelocationModel;
239 /// setRelocationModel - Sets the code generation relocation model.
240 void TargetMachine::setRelocationModel(Reloc::Model Model) {
241 RelocationModel = Model;
244 /// getCodeModel - Returns the code model. The choices are small, kernel,
245 /// medium, large, and target default.
246 CodeModel::Model TargetMachine::getCodeModel() {
250 /// setCodeModel - Sets the code model.
251 void TargetMachine::setCodeModel(CodeModel::Model Model) {
255 bool TargetMachine::getAsmVerbosityDefault() {
256 return AsmVerbosityDefault;
259 void TargetMachine::setAsmVerbosityDefault(bool V) {
260 AsmVerbosityDefault = V;
263 bool TargetMachine::getFunctionSections() {
264 return FunctionSections;
267 bool TargetMachine::getDataSections() {
271 void TargetMachine::setFunctionSections(bool V) {
272 FunctionSections = V;
275 void TargetMachine::setDataSections(bool V) {
280 /// DisableFramePointerElim - This returns true if frame pointer elimination
281 /// optimization should be disabled for the given machine function.
282 bool DisableFramePointerElim(const MachineFunction &MF) {
283 // Check to see if we should eliminate non-leaf frame pointers and then
284 // check to see if we should eliminate all frame pointers.
285 if (NoFramePointerElimNonLeaf && !NoFramePointerElim) {
286 const MachineFrameInfo *MFI = MF.getFrameInfo();
287 return MFI->hasCalls();
290 return NoFramePointerElim;
293 /// LessPreciseFPMAD - This flag return true when -enable-fp-mad option
294 /// is specified on the command line. When this flag is off(default), the
295 /// code generator is not allowed to generate mad (multiply add) if the
296 /// result is "less precise" than doing those operations individually.
297 bool LessPreciseFPMAD() { return UnsafeFPMath || LessPreciseFPMADOption; }
299 /// HonorSignDependentRoundingFPMath - Return true if the codegen must assume
300 /// that the rounding mode of the FPU can change from its default.
301 bool HonorSignDependentRoundingFPMath() {
302 return !UnsafeFPMath && HonorSignDependentRoundingFPMathOption;