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
18 #include "llvm/MC/MCTargetOptions.h"
21 class MachineFunction;
26 Default, // Target-specific (either soft or hard depending on triple, etc).
32 namespace FPOpFusion {
34 Fast, // Enable fusion of FP ops wherever it's profitable.
35 Standard, // Only allow fusion of 'blessed' ops (currently just fmuladd).
36 Strict // Never fuse FP-ops.
42 Single, // Use a single table for all indirect jumptable calls.
43 Arity, // Use one table per number of function parameters.
44 Simplified, // Use one table per function type, with types projected
45 // into 4 types: pointer to non-function, struct,
46 // primitive, and function pointer.
47 Full // Use one table per unique function type
51 namespace ThreadModel {
53 POSIX, // POSIX Threads
54 Single // Single Threaded Environment
58 namespace FPDenormal {
60 IEEE, // IEEE 754 denormal numbers
61 PreserveSign, // the sign of a flushed-to-zero number is preserved in
63 PositiveZero // denormals are flushed to positive zero
69 Default, // Default means not specified
70 EABI4, // Target-specific (either 4, 5 or gnu depending on triple).
75 /// Identify a debugger for "tuning" the debug info.
77 /// The "debugger tuning" concept allows us to present a more intuitive
78 /// interface that unpacks into different sets of defaults for the various
79 /// individual feature-flag settings, that suit the preferences of the
80 /// various debuggers. However, it's worth remembering that debuggers are
81 /// not the only consumers of debug info, and some variations in DWARF might
82 /// better be treated as target/platform issues. Fundamentally,
83 /// o if the feature is useful (or not) to a particular debugger, regardless
84 /// of the target, that's a tuning decision;
85 /// o if the feature is useful (or not) on a particular platform, regardless
86 /// of the debugger, that's a target decision.
87 /// It's not impossible to see both factors in some specific case.
89 /// The "tuning" should be used to set defaults for individual feature flags
90 /// in DwarfDebug; if a given feature has a more specific command-line option,
91 /// that option should take precedence over the tuning.
92 enum class DebuggerKind {
93 Default, // No specific tuning requested.
94 GDB, // Tune debug info for gdb.
95 LLDB, // Tune debug info for lldb.
96 SCE // Tune debug info for SCE targets (e.g. PS4).
102 : PrintMachineCode(false), UnsafeFPMath(false), NoInfsFPMath(false),
103 NoNaNsFPMath(false), NoTrappingFPMath(false),
104 NoSignedZerosFPMath(false),
105 HonorSignDependentRoundingFPMathOption(false), NoZerosInBSS(false),
106 GuaranteedTailCallOpt(false), StackSymbolOrdering(true),
107 EnableFastISel(false), UseInitArray(false),
108 DisableIntegratedAS(false), RelaxELFRelocations(false),
109 FunctionSections(false), DataSections(false),
110 UniqueSectionNames(true), TrapUnreachable(false), EmulatedTLS(false),
111 EnableIPRA(false), EmitStackSizeSection(false) {}
113 /// PrintMachineCode - This flag is enabled when the -print-machineinstrs
114 /// option is specified on the command line, and should enable debugging
115 /// output from the code generator.
116 unsigned PrintMachineCode : 1;
118 /// DisableFramePointerElim - This returns true if frame pointer elimination
119 /// optimization should be disabled for the given machine function.
120 bool DisableFramePointerElim(const MachineFunction &MF) const;
122 /// UnsafeFPMath - This flag is enabled when the
123 /// -enable-unsafe-fp-math flag is specified on the command line. When
124 /// this flag is off (the default), the code generator is not allowed to
125 /// produce results that are "less precise" than IEEE allows. This includes
126 /// use of X86 instructions like FSIN and FCOS instead of libcalls.
127 unsigned UnsafeFPMath : 1;
129 /// NoInfsFPMath - This flag is enabled when the
130 /// -enable-no-infs-fp-math flag is specified on the command line. When
131 /// this flag is off (the default), the code generator is not allowed to
132 /// assume the FP arithmetic arguments and results are never +-Infs.
133 unsigned NoInfsFPMath : 1;
135 /// NoNaNsFPMath - This flag is enabled when the
136 /// -enable-no-nans-fp-math flag is specified on the command line. When
137 /// this flag is off (the default), the code generator is not allowed to
138 /// assume the FP arithmetic arguments and results are never NaNs.
139 unsigned NoNaNsFPMath : 1;
141 /// NoTrappingFPMath - This flag is enabled when the
142 /// -enable-no-trapping-fp-math is specified on the command line. This
143 /// specifies that there are no trap handlers to handle exceptions.
144 unsigned NoTrappingFPMath : 1;
146 /// NoSignedZerosFPMath - This flag is enabled when the
147 /// -enable-no-signed-zeros-fp-math is specified on the command line. This
148 /// specifies that optimizations are allowed to treat the sign of a zero
149 /// argument or result as insignificant.
150 unsigned NoSignedZerosFPMath : 1;
152 /// HonorSignDependentRoundingFPMath - This returns true when the
153 /// -enable-sign-dependent-rounding-fp-math is specified. If this returns
154 /// false (the default), the code generator is allowed to assume that the
155 /// rounding behavior is the default (round-to-zero for all floating point
156 /// to integer conversions, and round-to-nearest for all other arithmetic
157 /// truncations). If this is enabled (set to true), the code generator must
158 /// assume that the rounding mode may dynamically change.
159 unsigned HonorSignDependentRoundingFPMathOption : 1;
160 bool HonorSignDependentRoundingFPMath() const;
162 /// NoZerosInBSS - By default some codegens place zero-initialized data to
163 /// .bss section. This flag disables such behaviour (necessary, e.g. for
164 /// crt*.o compiling).
165 unsigned NoZerosInBSS : 1;
167 /// GuaranteedTailCallOpt - This flag is enabled when -tailcallopt is
168 /// specified on the commandline. When the flag is on, participating targets
169 /// will perform tail call optimization on all calls which use the fastcc
170 /// calling convention and which satisfy certain target-independent
171 /// criteria (being at the end of a function, having the same return type
172 /// as their parent function, etc.), using an alternate ABI if necessary.
173 unsigned GuaranteedTailCallOpt : 1;
175 /// StackAlignmentOverride - Override default stack alignment for target.
176 unsigned StackAlignmentOverride = 0;
178 /// StackSymbolOrdering - When true, this will allow CodeGen to order
179 /// the local stack symbols (for code size, code locality, or any other
180 /// heuristics). When false, the local symbols are left in whatever order
181 /// they were generated. Default is true.
182 unsigned StackSymbolOrdering : 1;
184 /// EnableFastISel - This flag enables fast-path instruction selection
185 /// which trades away generated code quality in favor of reducing
187 unsigned EnableFastISel : 1;
189 /// UseInitArray - Use .init_array instead of .ctors for static
191 unsigned UseInitArray : 1;
193 /// Disable the integrated assembler.
194 unsigned DisableIntegratedAS : 1;
196 /// Compress DWARF debug sections.
197 DebugCompressionType CompressDebugSections = DebugCompressionType::None;
199 unsigned RelaxELFRelocations : 1;
201 /// Emit functions into separate sections.
202 unsigned FunctionSections : 1;
204 /// Emit data into separate sections.
205 unsigned DataSections : 1;
207 unsigned UniqueSectionNames : 1;
209 /// Emit target-specific trap instruction for 'unreachable' IR instructions.
210 unsigned TrapUnreachable : 1;
212 /// EmulatedTLS - This flag enables emulated TLS model, using emutls
213 /// function in the runtime library..
214 unsigned EmulatedTLS : 1;
216 /// This flag enables InterProcedural Register Allocation (IPRA).
217 unsigned EnableIPRA : 1;
219 /// Emit section containing metadata on function stack sizes.
220 unsigned EmitStackSizeSection : 1;
222 /// FloatABIType - This setting is set by -float-abi=xxx option is specfied
223 /// on the command line. This setting may either be Default, Soft, or Hard.
224 /// Default selects the target's default behavior. Soft selects the ABI for
225 /// software floating point, but does not indicate that FP hardware may not
226 /// be used. Such a combination is unfortunately popular (e.g.
227 /// arm-apple-darwin). Hard presumes that the normal FP ABI is used.
228 FloatABI::ABIType FloatABIType = FloatABI::Default;
230 /// AllowFPOpFusion - This flag is set by the -fuse-fp-ops=xxx option.
231 /// This controls the creation of fused FP ops that store intermediate
232 /// results in higher precision than IEEE allows (E.g. FMAs).
234 /// Fast mode - allows formation of fused FP ops whenever they're
236 /// Standard mode - allow fusion only for 'blessed' FP ops. At present the
237 /// only blessed op is the fmuladd intrinsic. In the future more blessed ops
239 /// Strict mode - allow fusion only if/when it can be proven that the excess
240 /// precision won't effect the result.
242 /// Note: This option only controls formation of fused ops by the
243 /// optimizers. Fused operations that are explicitly specified (e.g. FMA
244 /// via the llvm.fma.* intrinsic) will always be honored, regardless of
245 /// the value of this option.
246 FPOpFusion::FPOpFusionMode AllowFPOpFusion = FPOpFusion::Standard;
248 /// ThreadModel - This flag specifies the type of threading model to assume
249 /// for things like atomics
250 ThreadModel::Model ThreadModel = ThreadModel::POSIX;
252 /// EABIVersion - This flag specifies the EABI version
253 EABI EABIVersion = EABI::Default;
255 /// Which debugger to tune for.
256 DebuggerKind DebuggerTuning = DebuggerKind::Default;
258 /// FPDenormalMode - This flags specificies which denormal numbers the code
259 /// is permitted to require.
260 FPDenormal::DenormalMode FPDenormalMode = FPDenormal::IEEE;
262 /// What exception model to use
263 ExceptionHandling ExceptionModel = ExceptionHandling::None;
265 /// Machine level options.
266 MCTargetOptions MCOptions;
269 } // End llvm namespace