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/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"
20 using namespace llvm;
21
22 //---------------------------------------------------------------------------
23 // Command-line options that tend to be useful on more than one back-end.
24 //
25
26 namespace llvm {
27 bool LessPreciseFPMADOption;
28 bool PrintMachineCode;
29 bool NoFramePointerElim;
30 bool NoFramePointerElimNonLeaf;
31 bool NoExcessFPPrecision;
32 bool UnsafeFPMath;
33 bool NoInfsFPMath;
34 bool NoNaNsFPMath;
35 bool HonorSignDependentRoundingFPMathOption;
36 bool UseSoftFloat;
37 FloatABI::ABIType FloatABIType;
38 bool NoImplicitFloat;
39 bool NoZerosInBSS;
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;
48 bool RealignStack;
49 bool DisableJumpTables;
50 bool StrongPHIElim;
51 bool AsmVerbosityDefault(false);
52 }
53
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),
62 cl::init(false));
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),
67 cl::init(false));
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),
72 cl::init(false));
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),
77 cl::init(false));
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),
82 cl::init(false));
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),
87 cl::init(false));
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),
92 cl::init(false));
93 static cl::opt<bool, true>
94 EnableHonorSignDependentRoundingFPMath("enable-sign-dependent-rounding-fp-math",
95 cl::Hidden,
96 cl::desc("Force codegen to assume rounding mode can change dynamically"),
97 cl::location(HonorSignDependentRoundingFPMathOption),
98 cl::init(false));
99 static cl::opt<bool, true>
100 GenerateSoftFloatCalls("soft-float",
101 cl::desc("Generate software floating point library calls"),
102 cl::location(UseSoftFloat),
103 cl::init(false));
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),
109 cl::values(
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)"),
116 clEnumValEnd));
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),
121 cl::init(false));
122 static cl::opt<bool, true>
123 EnableJITExceptionHandling("jit-enable-eh",
124 cl::desc("Emit exception handling information"),
125 cl::location(JITExceptionHandling),
126 cl::init(false));
127 // In debug builds, make this default to true.
128 #ifdef NDEBUG
129 #define EMIT_DEBUG false
130 #else
131 #define EMIT_DEBUG true
132 #endif
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));
138 #undef EMIT_DEBUG
139 static cl::opt<bool, true>
140 EmitJitDebugInfoToDisk("jit-emit-debug-to-disk",
141 cl::Hidden,
142 cl::desc("Emit debug info objfiles to disk"),
143 cl::location(JITEmitDebugInfoToDisk),
144 cl::init(false));
145 static cl::opt<bool, true>
146 EnableUnwindTables("unwind-tables",
147 cl::desc("Generate unwinding tables for all functions"),
148 cl::location(UnwindTablesMandatory),
149 cl::init(false));
150
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),
156 cl::values(
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"),
165 clEnumValEnd));
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),
171 cl::values(
172 clEnumValN(CodeModel::Default, "default",
173 "Target default code model"),
174 clEnumValN(CodeModel::Small, "small",
175 "Small code model"),
176 clEnumValN(CodeModel::Kernel, "kernel",
177 "Kernel code model"),
178 clEnumValN(CodeModel::Medium, "medium",
179 "Medium code model"),
180 clEnumValN(CodeModel::Large, "large",
181 "Large code model"),
182 clEnumValEnd));
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),
187 cl::init(false));
188 static cl::opt<unsigned, true>
189 OverrideStackAlignment("stack-alignment",
190 cl::desc("Override default stack alignment"),
191 cl::location(StackAlignment),
192 cl::init(0));
193 static cl::opt<bool, true>
194 EnableRealignStack("realign-stack",
195 cl::desc("Realign stack if needed"),
196 cl::location(RealignStack),
197 cl::init(true));
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),
202 cl::init(false));
203 static cl::opt<bool, true>
204 EnableStrongPHIElim(cl::Hidden, "strong-phi-elim",
205 cl::desc("Use strong PHI elimination."),
206 cl::location(StrongPHIElim),
207 cl::init(false));
208 static cl::opt<bool>
209 DataSections("fdata-sections",
210 cl::desc("Emit data into separate sections"),
211 cl::init(false));
212 static cl::opt<bool>
213 FunctionSections("ffunction-sections",
214 cl::desc("Emit functions into separate sections"),
215 cl::init(false));
216 //---------------------------------------------------------------------------
217 // TargetMachine Class
218 //
219
TargetMachine(const Target & T)220 TargetMachine::TargetMachine(const Target &T)
221 : TheTarget(T), AsmInfo(0),
222 MCRelaxAll(false) {
223 // Typically it will be subtargets that will adjust FloatABIType from Default
224 // to Soft or Hard.
225 if (UseSoftFloat)
226 FloatABIType = FloatABI::Soft;
227 }
228
~TargetMachine()229 TargetMachine::~TargetMachine() {
230 delete AsmInfo;
231 }
232
233 /// getRelocationModel - Returns the code generation relocation model. The
234 /// choices are static, PIC, and dynamic-no-pic, and target default.
getRelocationModel()235 Reloc::Model TargetMachine::getRelocationModel() {
236 return RelocationModel;
237 }
238
239 /// setRelocationModel - Sets the code generation relocation model.
setRelocationModel(Reloc::Model Model)240 void TargetMachine::setRelocationModel(Reloc::Model Model) {
241 RelocationModel = Model;
242 }
243
244 /// getCodeModel - Returns the code model. The choices are small, kernel,
245 /// medium, large, and target default.
getCodeModel()246 CodeModel::Model TargetMachine::getCodeModel() {
247 return CMModel;
248 }
249
250 /// setCodeModel - Sets the code model.
setCodeModel(CodeModel::Model Model)251 void TargetMachine::setCodeModel(CodeModel::Model Model) {
252 CMModel = Model;
253 }
254
getAsmVerbosityDefault()255 bool TargetMachine::getAsmVerbosityDefault() {
256 return AsmVerbosityDefault;
257 }
258
setAsmVerbosityDefault(bool V)259 void TargetMachine::setAsmVerbosityDefault(bool V) {
260 AsmVerbosityDefault = V;
261 }
262
getFunctionSections()263 bool TargetMachine::getFunctionSections() {
264 return FunctionSections;
265 }
266
getDataSections()267 bool TargetMachine::getDataSections() {
268 return DataSections;
269 }
270
setFunctionSections(bool V)271 void TargetMachine::setFunctionSections(bool V) {
272 FunctionSections = V;
273 }
274
setDataSections(bool V)275 void TargetMachine::setDataSections(bool V) {
276 DataSections = V;
277 }
278
279 namespace llvm {
280 /// DisableFramePointerElim - This returns true if frame pointer elimination
281 /// optimization should be disabled for the given machine function.
DisableFramePointerElim(const MachineFunction & MF)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();
288 }
289
290 return NoFramePointerElim;
291 }
292
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.
LessPreciseFPMAD()297 bool LessPreciseFPMAD() { return UnsafeFPMath || LessPreciseFPMADOption; }
298
299 /// HonorSignDependentRoundingFPMath - Return true if the codegen must assume
300 /// that the rounding mode of the FPU can change from its default.
HonorSignDependentRoundingFPMath()301 bool HonorSignDependentRoundingFPMath() {
302 return !UnsafeFPMath && HonorSignDependentRoundingFPMathOption;
303 }
304 }
305