1 //===-- llvm/Target/TargetOptions.h - Target Options ------------*- C++ -*-===//
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 defines command line option flags that are shared across various
13 //===----------------------------------------------------------------------===//
15 #ifndef LLVM_TARGET_TARGETOPTIONS_H
16 #define LLVM_TARGET_TARGETOPTIONS_H
21 class MachineFunction;
24 // Possible float ABI settings. Used with FloatABIType in TargetOptions.h.
27 Default, // Target-specific (either soft or hard depending on triple, etc).
33 namespace FPOpFusion {
35 Fast, // Enable fusion of FP ops wherever it's profitable.
36 Standard, // Only allow fusion of 'blessed' ops (currently just fmuladd).
37 Strict // Never fuse FP-ops.
44 : PrintMachineCode(false), NoFramePointerElim(false),
45 NoFramePointerElimNonLeaf(false), LessPreciseFPMADOption(false),
46 UnsafeFPMath(false), NoInfsFPMath(false),
47 NoNaNsFPMath(false), HonorSignDependentRoundingFPMathOption(false),
48 UseSoftFloat(false), NoZerosInBSS(false), JITExceptionHandling(false),
49 JITEmitDebugInfo(false), JITEmitDebugInfoToDisk(false),
50 GuaranteedTailCallOpt(false), DisableTailCalls(false),
51 StackAlignmentOverride(0), RealignStack(true),
52 DisableJumpTables(false), EnableFastISel(false),
53 PositionIndependentExecutable(false), EnableSegmentedStacks(false),
54 UseInitArray(false), TrapFuncName(""), FloatABIType(FloatABI::Default),
55 AllowFPOpFusion(FPOpFusion::Standard)
58 /// PrintMachineCode - This flag is enabled when the -print-machineinstrs
59 /// option is specified on the command line, and should enable debugging
60 /// output from the code generator.
61 unsigned PrintMachineCode : 1;
63 /// NoFramePointerElim - This flag is enabled when the -disable-fp-elim is
64 /// specified on the command line. If the target supports the frame pointer
65 /// elimination optimization, this option should disable it.
66 unsigned NoFramePointerElim : 1;
68 /// NoFramePointerElimNonLeaf - This flag is enabled when the
69 /// -disable-non-leaf-fp-elim is specified on the command line. If the
70 /// target supports the frame pointer elimination optimization, this option
71 /// should disable it for non-leaf functions.
72 unsigned NoFramePointerElimNonLeaf : 1;
74 /// DisableFramePointerElim - This returns true if frame pointer elimination
75 /// optimization should be disabled for the given machine function.
76 bool DisableFramePointerElim(const MachineFunction &MF) const;
78 /// LessPreciseFPMAD - This flag is enabled when the
79 /// -enable-fp-mad is specified on the command line. When this flag is off
80 /// (the default), the code generator is not allowed to generate mad
81 /// (multiply add) if the result is "less precise" than doing those
82 /// operations individually.
83 unsigned LessPreciseFPMADOption : 1;
84 bool LessPreciseFPMAD() const;
86 /// UnsafeFPMath - This flag is enabled when the
87 /// -enable-unsafe-fp-math flag is specified on the command line. When
88 /// this flag is off (the default), the code generator is not allowed to
89 /// produce results that are "less precise" than IEEE allows. This includes
90 /// use of X86 instructions like FSIN and FCOS instead of libcalls.
91 /// UnsafeFPMath implies LessPreciseFPMAD.
92 unsigned UnsafeFPMath : 1;
94 /// NoInfsFPMath - This flag is enabled when the
95 /// -enable-no-infs-fp-math flag is specified on the command line. When
96 /// this flag is off (the default), the code generator is not allowed to
97 /// assume the FP arithmetic arguments and results are never +-Infs.
98 unsigned NoInfsFPMath : 1;
100 /// NoNaNsFPMath - This flag is enabled when the
101 /// -enable-no-nans-fp-math flag is specified on the command line. When
102 /// this flag is off (the default), the code generator is not allowed to
103 /// assume the FP arithmetic arguments and results are never NaNs.
104 unsigned NoNaNsFPMath : 1;
106 /// HonorSignDependentRoundingFPMath - This returns true when the
107 /// -enable-sign-dependent-rounding-fp-math is specified. If this returns
108 /// false (the default), the code generator is allowed to assume that the
109 /// rounding behavior is the default (round-to-zero for all floating point
110 /// to integer conversions, and round-to-nearest for all other arithmetic
111 /// truncations). If this is enabled (set to true), the code generator must
112 /// assume that the rounding mode may dynamically change.
113 unsigned HonorSignDependentRoundingFPMathOption : 1;
114 bool HonorSignDependentRoundingFPMath() const;
116 /// UseSoftFloat - This flag is enabled when the -soft-float flag is
117 /// specified on the command line. When this flag is on, the code generator
118 /// will generate libcalls to the software floating point library instead of
119 /// target FP instructions.
120 unsigned UseSoftFloat : 1;
122 /// NoZerosInBSS - By default some codegens place zero-initialized data to
123 /// .bss section. This flag disables such behaviour (necessary, e.g. for
124 /// crt*.o compiling).
125 unsigned NoZerosInBSS : 1;
127 /// JITExceptionHandling - This flag indicates that the JIT should emit
128 /// exception handling information.
129 unsigned JITExceptionHandling : 1;
131 /// JITEmitDebugInfo - This flag indicates that the JIT should try to emit
132 /// debug information and notify a debugger about it.
133 unsigned JITEmitDebugInfo : 1;
135 /// JITEmitDebugInfoToDisk - This flag indicates that the JIT should write
136 /// the object files generated by the JITEmitDebugInfo flag to disk. This
137 /// flag is hidden and is only for debugging the debug info.
138 unsigned JITEmitDebugInfoToDisk : 1;
140 /// GuaranteedTailCallOpt - This flag is enabled when -tailcallopt is
141 /// specified on the commandline. When the flag is on, participating targets
142 /// will perform tail call optimization on all calls which use the fastcc
143 /// calling convention and which satisfy certain target-independent
144 /// criteria (being at the end of a function, having the same return type
145 /// as their parent function, etc.), using an alternate ABI if necessary.
146 unsigned GuaranteedTailCallOpt : 1;
148 /// DisableTailCalls - This flag controls whether we will use tail calls.
149 /// Disabling them may be useful to maintain a correct call stack.
150 unsigned DisableTailCalls : 1;
152 /// StackAlignmentOverride - Override default stack alignment for target.
153 unsigned StackAlignmentOverride;
155 /// RealignStack - This flag indicates whether the stack should be
156 /// automatically realigned, if needed.
157 unsigned RealignStack : 1;
159 /// DisableJumpTables - This flag indicates jump tables should not be
161 unsigned DisableJumpTables : 1;
163 /// EnableFastISel - This flag enables fast-path instruction selection
164 /// which trades away generated code quality in favor of reducing
166 unsigned EnableFastISel : 1;
168 /// PositionIndependentExecutable - This flag indicates whether the code
169 /// will eventually be linked into a single executable, despite the PIC
170 /// relocation model being in use. It's value is undefined (and irrelevant)
171 /// if the relocation model is anything other than PIC.
172 unsigned PositionIndependentExecutable : 1;
174 unsigned EnableSegmentedStacks : 1;
176 /// UseInitArray - Use .init_array instead of .ctors for static
178 unsigned UseInitArray : 1;
180 /// getTrapFunctionName - If this returns a non-empty string, this means
181 /// isel should lower Intrinsic::trap to a call to the specified function
182 /// name instead of an ISD::TRAP node.
183 std::string TrapFuncName;
184 StringRef getTrapFunctionName() const;
186 /// FloatABIType - This setting is set by -float-abi=xxx option is specfied
187 /// on the command line. This setting may either be Default, Soft, or Hard.
188 /// Default selects the target's default behavior. Soft selects the ABI for
189 /// UseSoftFloat, but does not indicate that FP hardware may not be used.
190 /// Such a combination is unfortunately popular (e.g. arm-apple-darwin).
191 /// Hard presumes that the normal FP ABI is used.
192 FloatABI::ABIType FloatABIType;
194 /// AllowFPOpFusion - This flag is set by the -fuse-fp-ops=xxx option.
195 /// This controls the creation of fused FP ops that store intermediate
196 /// results in higher precision than IEEE allows (E.g. FMAs).
198 /// Fast mode - allows formation of fused FP ops whenever they're
200 /// Standard mode - allow fusion only for 'blessed' FP ops. At present the
201 /// only blessed op is the fmuladd intrinsic. In the future more blessed ops
203 /// Strict mode - allow fusion only if/when it can be proven that the excess
204 /// precision won't effect the result.
206 /// Note: This option only controls formation of fused ops by the optimizers.
207 /// Fused operations that are explicitly specified (e.g. FMA via the
208 /// llvm.fma.* intrinsic) will always be honored, regardless of the value of
210 FPOpFusion::FPOpFusionMode AllowFPOpFusion;
213 } // End llvm namespace