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 GuaranteedTailCallOpt;
44 unsigned StackAlignmentOverride;
45 bool RealignStack;
46 bool DisableJumpTables;
47 bool StrongPHIElim;
48 bool HasDivModLibcall;
49 bool AsmVerbosityDefault(false);
50 bool EnableSegmentedStacks;
51 }
52
53 static cl::opt<bool, true>
54 PrintCode("print-machineinstrs",
55 cl::desc("Print generated machine code"),
56 cl::location(PrintMachineCode), cl::init(false));
57 static cl::opt<bool, true>
58 DisableFPElim("disable-fp-elim",
59 cl::desc("Disable frame pointer elimination optimization"),
60 cl::location(NoFramePointerElim),
61 cl::init(false));
62 static cl::opt<bool, true>
63 DisableFPElimNonLeaf("disable-non-leaf-fp-elim",
64 cl::desc("Disable frame pointer elimination optimization for non-leaf funcs"),
65 cl::location(NoFramePointerElimNonLeaf),
66 cl::init(false));
67 static cl::opt<bool, true>
68 DisableExcessPrecision("disable-excess-fp-precision",
69 cl::desc("Disable optimizations that may increase FP precision"),
70 cl::location(NoExcessFPPrecision),
71 cl::init(false));
72 static cl::opt<bool, true>
73 EnableFPMAD("enable-fp-mad",
74 cl::desc("Enable less precise MAD instructions to be generated"),
75 cl::location(LessPreciseFPMADOption),
76 cl::init(false));
77 static cl::opt<bool, true>
78 EnableUnsafeFPMath("enable-unsafe-fp-math",
79 cl::desc("Enable optimizations that may decrease FP precision"),
80 cl::location(UnsafeFPMath),
81 cl::init(false));
82 static cl::opt<bool, true>
83 EnableNoInfsFPMath("enable-no-infs-fp-math",
84 cl::desc("Enable FP math optimizations that assume no +-Infs"),
85 cl::location(NoInfsFPMath),
86 cl::init(false));
87 static cl::opt<bool, true>
88 EnableNoNaNsFPMath("enable-no-nans-fp-math",
89 cl::desc("Enable FP math optimizations that assume no NaNs"),
90 cl::location(NoNaNsFPMath),
91 cl::init(false));
92 static cl::opt<bool, true>
93 EnableHonorSignDependentRoundingFPMath("enable-sign-dependent-rounding-fp-math",
94 cl::Hidden,
95 cl::desc("Force codegen to assume rounding mode can change dynamically"),
96 cl::location(HonorSignDependentRoundingFPMathOption),
97 cl::init(false));
98 static cl::opt<bool, true>
99 GenerateSoftFloatCalls("soft-float",
100 cl::desc("Generate software floating point library calls"),
101 cl::location(UseSoftFloat),
102 cl::init(false));
103 static cl::opt<llvm::FloatABI::ABIType, true>
104 FloatABIForCalls("float-abi",
105 cl::desc("Choose float ABI type"),
106 cl::location(FloatABIType),
107 cl::init(FloatABI::Default),
108 cl::values(
109 clEnumValN(FloatABI::Default, "default",
110 "Target default float ABI type"),
111 clEnumValN(FloatABI::Soft, "soft",
112 "Soft float ABI (implied by -soft-float)"),
113 clEnumValN(FloatABI::Hard, "hard",
114 "Hard float ABI (uses FP registers)"),
115 clEnumValEnd));
116 static cl::opt<bool, true>
117 DontPlaceZerosInBSS("nozero-initialized-in-bss",
118 cl::desc("Don't place zero-initialized symbols into bss section"),
119 cl::location(NoZerosInBSS),
120 cl::init(false));
121 static cl::opt<bool, true>
122 EnableJITExceptionHandling("jit-enable-eh",
123 cl::desc("Emit exception handling information"),
124 cl::location(JITExceptionHandling),
125 cl::init(false));
126 // In debug builds, make this default to true.
127 #ifdef NDEBUG
128 #define EMIT_DEBUG false
129 #else
130 #define EMIT_DEBUG true
131 #endif
132 static cl::opt<bool, true>
133 EmitJitDebugInfo("jit-emit-debug",
134 cl::desc("Emit debug information to debugger"),
135 cl::location(JITEmitDebugInfo),
136 cl::init(EMIT_DEBUG));
137 #undef EMIT_DEBUG
138 static cl::opt<bool, true>
139 EmitJitDebugInfoToDisk("jit-emit-debug-to-disk",
140 cl::Hidden,
141 cl::desc("Emit debug info objfiles to disk"),
142 cl::location(JITEmitDebugInfoToDisk),
143 cl::init(false));
144
145 static cl::opt<bool, true>
146 EnableGuaranteedTailCallOpt("tailcallopt",
147 cl::desc("Turn fastcc calls into tail calls by (potentially) changing ABI."),
148 cl::location(GuaranteedTailCallOpt),
149 cl::init(false));
150 static cl::opt<unsigned, true>
151 OverrideStackAlignment("stack-alignment",
152 cl::desc("Override default stack alignment"),
153 cl::location(StackAlignmentOverride),
154 cl::init(0));
155 static cl::opt<bool, true>
156 EnableRealignStack("realign-stack",
157 cl::desc("Realign stack if needed"),
158 cl::location(RealignStack),
159 cl::init(true));
160 static cl::opt<bool, true>
161 DisableSwitchTables(cl::Hidden, "disable-jump-tables",
162 cl::desc("Do not generate jump tables."),
163 cl::location(DisableJumpTables),
164 cl::init(false));
165 static cl::opt<bool, true>
166 EnableStrongPHIElim(cl::Hidden, "strong-phi-elim",
167 cl::desc("Use strong PHI elimination."),
168 cl::location(StrongPHIElim),
169 cl::init(false));
170 static cl::opt<std::string>
171 TrapFuncName("trap-func", cl::Hidden,
172 cl::desc("Emit a call to trap function rather than a trap instruction"),
173 cl::init(""));
174 static cl::opt<bool>
175 DataSections("fdata-sections",
176 cl::desc("Emit data into separate sections"),
177 cl::init(false));
178 static cl::opt<bool>
179 FunctionSections("ffunction-sections",
180 cl::desc("Emit functions into separate sections"),
181 cl::init(false));
182 static cl::opt<bool, true>
183 SegmentedStacks("segmented-stacks",
184 cl::desc("Use segmented stacks if possible."),
185 cl::location(EnableSegmentedStacks),
186 cl::init(false));
187
188 //---------------------------------------------------------------------------
189 // TargetMachine Class
190 //
191
TargetMachine(const Target & T,StringRef TT,StringRef CPU,StringRef FS)192 TargetMachine::TargetMachine(const Target &T,
193 StringRef TT, StringRef CPU, StringRef FS)
194 : TheTarget(T), TargetTriple(TT), TargetCPU(CPU), TargetFS(FS),
195 CodeGenInfo(0), AsmInfo(0),
196 MCRelaxAll(false),
197 MCNoExecStack(false),
198 MCSaveTempLabels(false),
199 MCUseLoc(true),
200 MCUseCFI(true) {
201 // Typically it will be subtargets that will adjust FloatABIType from Default
202 // to Soft or Hard.
203 if (UseSoftFloat)
204 FloatABIType = FloatABI::Soft;
205 }
206
~TargetMachine()207 TargetMachine::~TargetMachine() {
208 delete CodeGenInfo;
209 delete AsmInfo;
210 }
211
212 /// getRelocationModel - Returns the code generation relocation model. The
213 /// choices are static, PIC, and dynamic-no-pic, and target default.
getRelocationModel() const214 Reloc::Model TargetMachine::getRelocationModel() const {
215 if (!CodeGenInfo)
216 return Reloc::Default;
217 return CodeGenInfo->getRelocationModel();
218 }
219
220 /// getCodeModel - Returns the code model. The choices are small, kernel,
221 /// medium, large, and target default.
getCodeModel() const222 CodeModel::Model TargetMachine::getCodeModel() const {
223 if (!CodeGenInfo)
224 return CodeModel::Default;
225 return CodeGenInfo->getCodeModel();
226 }
227
getAsmVerbosityDefault()228 bool TargetMachine::getAsmVerbosityDefault() {
229 return AsmVerbosityDefault;
230 }
231
setAsmVerbosityDefault(bool V)232 void TargetMachine::setAsmVerbosityDefault(bool V) {
233 AsmVerbosityDefault = V;
234 }
235
getFunctionSections()236 bool TargetMachine::getFunctionSections() {
237 return FunctionSections;
238 }
239
getDataSections()240 bool TargetMachine::getDataSections() {
241 return DataSections;
242 }
243
setFunctionSections(bool V)244 void TargetMachine::setFunctionSections(bool V) {
245 FunctionSections = V;
246 }
247
setDataSections(bool V)248 void TargetMachine::setDataSections(bool V) {
249 DataSections = V;
250 }
251
252 namespace llvm {
253 /// DisableFramePointerElim - This returns true if frame pointer elimination
254 /// optimization should be disabled for the given machine function.
DisableFramePointerElim(const MachineFunction & MF)255 bool DisableFramePointerElim(const MachineFunction &MF) {
256 // Check to see if we should eliminate non-leaf frame pointers and then
257 // check to see if we should eliminate all frame pointers.
258 if (NoFramePointerElimNonLeaf && !NoFramePointerElim) {
259 const MachineFrameInfo *MFI = MF.getFrameInfo();
260 return MFI->hasCalls();
261 }
262
263 return NoFramePointerElim;
264 }
265
266 /// LessPreciseFPMAD - This flag return true when -enable-fp-mad option
267 /// is specified on the command line. When this flag is off(default), the
268 /// code generator is not allowed to generate mad (multiply add) if the
269 /// result is "less precise" than doing those operations individually.
LessPreciseFPMAD()270 bool LessPreciseFPMAD() { return UnsafeFPMath || LessPreciseFPMADOption; }
271
272 /// HonorSignDependentRoundingFPMath - Return true if the codegen must assume
273 /// that the rounding mode of the FPU can change from its default.
HonorSignDependentRoundingFPMath()274 bool HonorSignDependentRoundingFPMath() {
275 return !UnsafeFPMath && HonorSignDependentRoundingFPMathOption;
276 }
277
278 /// getTrapFunctionName - If this returns a non-empty string, this means isel
279 /// should lower Intrinsic::trap to a call to the specified function name
280 /// instead of an ISD::TRAP node.
getTrapFunctionName()281 StringRef getTrapFunctionName() {
282 return TrapFuncName;
283 }
284 }
285