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).
36 : PrintMachineCode(false), NoFramePointerElim(false),
37 NoFramePointerElimNonLeaf(false), LessPreciseFPMADOption(false),
38 NoExcessFPPrecision(false), UnsafeFPMath(false), NoInfsFPMath(false),
39 NoNaNsFPMath(false), HonorSignDependentRoundingFPMathOption(false),
40 UseSoftFloat(false), NoZerosInBSS(false), JITExceptionHandling(false),
41 JITEmitDebugInfo(false), JITEmitDebugInfoToDisk(false),
42 GuaranteedTailCallOpt(false), DisableTailCalls(false),
43 StackAlignmentOverride(0), RealignStack(true),
44 DisableJumpTables(false), EnableFastISel(false),
45 PositionIndependentExecutable(false), EnableSegmentedStacks(false),
46 TrapFuncName(""), FloatABIType(FloatABI::Default)
49 /// PrintMachineCode - This flag is enabled when the -print-machineinstrs
50 /// option is specified on the command line, and should enable debugging
51 /// output from the code generator.
52 unsigned PrintMachineCode : 1;
54 /// NoFramePointerElim - This flag is enabled when the -disable-fp-elim is
55 /// specified on the command line. If the target supports the frame pointer
56 /// elimination optimization, this option should disable it.
57 unsigned NoFramePointerElim : 1;
59 /// NoFramePointerElimNonLeaf - This flag is enabled when the
60 /// -disable-non-leaf-fp-elim is specified on the command line. If the
61 /// target supports the frame pointer elimination optimization, this option
62 /// should disable it for non-leaf functions.
63 unsigned NoFramePointerElimNonLeaf : 1;
65 /// DisableFramePointerElim - This returns true if frame pointer elimination
66 /// optimization should be disabled for the given machine function.
67 bool DisableFramePointerElim(const MachineFunction &MF) const;
69 /// LessPreciseFPMAD - This flag is enabled when the
70 /// -enable-fp-mad is specified on the command line. When this flag is off
71 /// (the default), the code generator is not allowed to generate mad
72 /// (multiply add) if the result is "less precise" than doing those
73 /// operations individually.
74 unsigned LessPreciseFPMADOption : 1;
75 bool LessPreciseFPMAD() const;
77 /// NoExcessFPPrecision - This flag is enabled when the
78 /// -disable-excess-fp-precision flag is specified on the command line.
79 /// When this flag is off (the default), the code generator is allowed to
80 /// produce results that are "more precise" than IEEE allows. This includes
81 /// use of FMA-like operations and use of the X86 FP registers without
82 /// rounding all over the place.
83 unsigned NoExcessFPPrecision : 1;
85 /// UnsafeFPMath - This flag is enabled when the
86 /// -enable-unsafe-fp-math flag is specified on the command line. When
87 /// this flag is off (the default), the code generator is not allowed to
88 /// produce results that are "less precise" than IEEE allows. This includes
89 /// use of X86 instructions like FSIN and FCOS instead of libcalls.
90 /// UnsafeFPMath implies LessPreciseFPMAD.
91 unsigned UnsafeFPMath : 1;
93 /// NoInfsFPMath - This flag is enabled when the
94 /// -enable-no-infs-fp-math flag is specified on the command line. When
95 /// this flag is off (the default), the code generator is not allowed to
96 /// assume the FP arithmetic arguments and results are never +-Infs.
97 unsigned NoInfsFPMath : 1;
99 /// NoNaNsFPMath - This flag is enabled when the
100 /// -enable-no-nans-fp-math flag is specified on the command line. When
101 /// this flag is off (the default), the code generator is not allowed to
102 /// assume the FP arithmetic arguments and results are never NaNs.
103 unsigned NoNaNsFPMath : 1;
105 /// HonorSignDependentRoundingFPMath - This returns true when the
106 /// -enable-sign-dependent-rounding-fp-math is specified. If this returns
107 /// false (the default), the code generator is allowed to assume that the
108 /// rounding behavior is the default (round-to-zero for all floating point
109 /// to integer conversions, and round-to-nearest for all other arithmetic
110 /// truncations). If this is enabled (set to true), the code generator must
111 /// assume that the rounding mode may dynamically change.
112 unsigned HonorSignDependentRoundingFPMathOption : 1;
113 bool HonorSignDependentRoundingFPMath() const;
115 /// UseSoftFloat - This flag is enabled when the -soft-float flag is
116 /// specified on the command line. When this flag is on, the code generator
117 /// will generate libcalls to the software floating point library instead of
118 /// target FP instructions.
119 unsigned UseSoftFloat : 1;
121 /// NoZerosInBSS - By default some codegens place zero-initialized data to
122 /// .bss section. This flag disables such behaviour (necessary, e.g. for
123 /// crt*.o compiling).
124 unsigned NoZerosInBSS : 1;
126 /// JITExceptionHandling - This flag indicates that the JIT should emit
127 /// exception handling information.
128 unsigned JITExceptionHandling : 1;
130 /// JITEmitDebugInfo - This flag indicates that the JIT should try to emit
131 /// debug information and notify a debugger about it.
132 unsigned JITEmitDebugInfo : 1;
134 /// JITEmitDebugInfoToDisk - This flag indicates that the JIT should write
135 /// the object files generated by the JITEmitDebugInfo flag to disk. This
136 /// flag is hidden and is only for debugging the debug info.
137 unsigned JITEmitDebugInfoToDisk : 1;
139 /// GuaranteedTailCallOpt - This flag is enabled when -tailcallopt is
140 /// specified on the commandline. When the flag is on, participating targets
141 /// will perform tail call optimization on all calls which use the fastcc
142 /// calling convention and which satisfy certain target-independent
143 /// criteria (being at the end of a function, having the same return type
144 /// as their parent function, etc.), using an alternate ABI if necessary.
145 unsigned GuaranteedTailCallOpt : 1;
147 /// DisableTailCalls - This flag controls whether we will use tail calls.
148 /// Disabling them may be useful to maintain a correct call stack.
149 unsigned DisableTailCalls : 1;
151 /// StackAlignmentOverride - Override default stack alignment for target.
152 unsigned StackAlignmentOverride;
154 /// RealignStack - This flag indicates whether the stack should be
155 /// automatically realigned, if needed.
156 unsigned RealignStack : 1;
158 /// DisableJumpTables - This flag indicates jump tables should not be
160 unsigned DisableJumpTables : 1;
162 /// EnableFastISel - This flag enables fast-path instruction selection
163 /// which trades away generated code quality in favor of reducing
165 unsigned EnableFastISel : 1;
167 /// PositionIndependentExecutable - This flag indicates whether the code
168 /// will eventually be linked into a single executable, despite the PIC
169 /// relocation model being in use. It's value is undefined (and irrelevant)
170 /// if the relocation model is anything other than PIC.
171 unsigned PositionIndependentExecutable : 1;
173 unsigned EnableSegmentedStacks : 1;
175 /// getTrapFunctionName - If this returns a non-empty string, this means
176 /// isel should lower Intrinsic::trap to a call to the specified function
177 /// name instead of an ISD::TRAP node.
178 std::string TrapFuncName;
179 StringRef getTrapFunctionName() const;
181 /// FloatABIType - This setting is set by -float-abi=xxx option is specfied
182 /// on the command line. This setting may either be Default, Soft, or Hard.
183 /// Default selects the target's default behavior. Soft selects the ABI for
184 /// UseSoftFloat, but does not indicate that FP hardware may not be used.
185 /// Such a combination is unfortunately popular (e.g. arm-apple-darwin).
186 /// Hard presumes that the normal FP ABI is used.
187 FloatABI::ABIType FloatABIType;
189 } // End llvm namespace