TargetOptions.h revision 263508 
1//===-- llvm/Target/TargetOptions.h - Target Options ------------*- C++ -*-===//
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 defines command line option flags that are shared across various
11// targets.
12//
13//===----------------------------------------------------------------------===//
14
15#ifndef LLVM_TARGET_TARGETOPTIONS_H
16#define LLVM_TARGET_TARGETOPTIONS_H
17
18#include <string>
19
20namespace llvm {
21  class MachineFunction;
22  class StringRef;
23
24  // Possible float ABI settings. Used with FloatABIType in TargetOptions.h.
25  namespace FloatABI {
26    enum ABIType {
27      Default, // Target-specific (either soft or hard depending on triple,etc).
28      Soft, // Soft float.
29      Hard  // Hard float.
30    };
31  }
32
33  namespace FPOpFusion {
34    enum FPOpFusionMode {
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.
38    };
39  }
40
41  class TargetOptions {
42  public:
43    TargetOptions()
44        : PrintMachineCode(false), NoFramePointerElim(false),
45          LessPreciseFPMADOption(false),
46          UnsafeFPMath(false), NoInfsFPMath(false),
47          NoNaNsFPMath(false), HonorSignDependentRoundingFPMathOption(false),
48          UseSoftFloat(false), NoZerosInBSS(false),
49          JITEmitDebugInfo(false), JITEmitDebugInfoToDisk(false),
50          GuaranteedTailCallOpt(false), DisableTailCalls(false),
51          StackAlignmentOverride(0),
52          EnableFastISel(false), PositionIndependentExecutable(false),
53          EnableSegmentedStacks(false), UseInitArray(false), TrapFuncName(""),
54          FloatABIType(FloatABI::Default), AllowFPOpFusion(FPOpFusion::Standard)
55    {}
56
57    /// PrintMachineCode - This flag is enabled when the -print-machineinstrs
58    /// option is specified on the command line, and should enable debugging
59    /// output from the code generator.
60    unsigned PrintMachineCode : 1;
61
62    /// NoFramePointerElim - This flag is enabled when the -disable-fp-elim is
63    /// specified on the command line.  If the target supports the frame pointer
64    /// elimination optimization, this option should disable it.
65    unsigned NoFramePointerElim : 1;
66
67    /// DisableFramePointerElim - This returns true if frame pointer elimination
68    /// optimization should be disabled for the given machine function.
69    bool DisableFramePointerElim(const MachineFunction &MF) const;
70
71    /// LessPreciseFPMAD - This flag is enabled when the
72    /// -enable-fp-mad is specified on the command line.  When this flag is off
73    /// (the default), the code generator is not allowed to generate mad
74    /// (multiply add) if the result is "less precise" than doing those
75    /// operations individually.
76    unsigned LessPreciseFPMADOption : 1;
77    bool LessPreciseFPMAD() const;
78
79    /// UnsafeFPMath - This flag is enabled when the
80    /// -enable-unsafe-fp-math flag is specified on the command line.  When
81    /// this flag is off (the default), the code generator is not allowed to
82    /// produce results that are "less precise" than IEEE allows.  This includes
83    /// use of X86 instructions like FSIN and FCOS instead of libcalls.
84    /// UnsafeFPMath implies LessPreciseFPMAD.
85    unsigned UnsafeFPMath : 1;
86
87    /// NoInfsFPMath - This flag is enabled when the
88    /// -enable-no-infs-fp-math flag is specified on the command line. When
89    /// this flag is off (the default), the code generator is not allowed to
90    /// assume the FP arithmetic arguments and results are never +-Infs.
91    unsigned NoInfsFPMath : 1;
92
93    /// NoNaNsFPMath - This flag is enabled when the
94    /// -enable-no-nans-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 NaNs.
97    unsigned NoNaNsFPMath : 1;
98
99    /// HonorSignDependentRoundingFPMath - This returns true when the
100    /// -enable-sign-dependent-rounding-fp-math is specified.  If this returns
101    /// false (the default), the code generator is allowed to assume that the
102    /// rounding behavior is the default (round-to-zero for all floating point
103    /// to integer conversions, and round-to-nearest for all other arithmetic
104    /// truncations).  If this is enabled (set to true), the code generator must
105    /// assume that the rounding mode may dynamically change.
106    unsigned HonorSignDependentRoundingFPMathOption : 1;
107    bool HonorSignDependentRoundingFPMath() const;
108
109    /// UseSoftFloat - This flag is enabled when the -soft-float flag is
110    /// specified on the command line.  When this flag is on, the code generator
111    /// will generate libcalls to the software floating point library instead of
112    /// target FP instructions.
113    unsigned UseSoftFloat : 1;
114
115    /// NoZerosInBSS - By default some codegens place zero-initialized data to
116    /// .bss section. This flag disables such behaviour (necessary, e.g. for
117    /// crt*.o compiling).
118    unsigned NoZerosInBSS : 1;
119
120    /// JITEmitDebugInfo - This flag indicates that the JIT should try to emit
121    /// debug information and notify a debugger about it.
122    unsigned JITEmitDebugInfo : 1;
123
124    /// JITEmitDebugInfoToDisk - This flag indicates that the JIT should write
125    /// the object files generated by the JITEmitDebugInfo flag to disk.  This
126    /// flag is hidden and is only for debugging the debug info.
127    unsigned JITEmitDebugInfoToDisk : 1;
128
129    /// GuaranteedTailCallOpt - This flag is enabled when -tailcallopt is
130    /// specified on the commandline. When the flag is on, participating targets
131    /// will perform tail call optimization on all calls which use the fastcc
132    /// calling convention and which satisfy certain target-independent
133    /// criteria (being at the end of a function, having the same return type
134    /// as their parent function, etc.), using an alternate ABI if necessary.
135    unsigned GuaranteedTailCallOpt : 1;
136
137    /// DisableTailCalls - This flag controls whether we will use tail calls.
138    /// Disabling them may be useful to maintain a correct call stack.
139    unsigned DisableTailCalls : 1;
140
141    /// StackAlignmentOverride - Override default stack alignment for target.
142    unsigned StackAlignmentOverride;
143
144    /// EnableFastISel - This flag enables fast-path instruction selection
145    /// which trades away generated code quality in favor of reducing
146    /// compile time.
147    unsigned EnableFastISel : 1;
148
149    /// PositionIndependentExecutable - This flag indicates whether the code
150    /// will eventually be linked into a single executable, despite the PIC
151    /// relocation model being in use. It's value is undefined (and irrelevant)
152    /// if the relocation model is anything other than PIC.
153    unsigned PositionIndependentExecutable : 1;
154
155    unsigned EnableSegmentedStacks : 1;
156
157    /// UseInitArray - Use .init_array instead of .ctors for static
158    /// constructors.
159    unsigned UseInitArray : 1;
160
161    /// getTrapFunctionName - If this returns a non-empty string, this means
162    /// isel should lower Intrinsic::trap to a call to the specified function
163    /// name instead of an ISD::TRAP node.
164    std::string TrapFuncName;
165    StringRef getTrapFunctionName() const;
166
167    /// FloatABIType - This setting is set by -float-abi=xxx option is specfied
168    /// on the command line. This setting may either be Default, Soft, or Hard.
169    /// Default selects the target's default behavior. Soft selects the ABI for
170    /// UseSoftFloat, but does not indicate that FP hardware may not be used.
171    /// Such a combination is unfortunately popular (e.g. arm-apple-darwin).
172    /// Hard presumes that the normal FP ABI is used.
173    FloatABI::ABIType FloatABIType;
174
175    /// AllowFPOpFusion - This flag is set by the -fuse-fp-ops=xxx option.
176    /// This controls the creation of fused FP ops that store intermediate
177    /// results in higher precision than IEEE allows (E.g. FMAs).
178    ///
179    /// Fast mode - allows formation of fused FP ops whenever they're
180    /// profitable.
181    /// Standard mode - allow fusion only for 'blessed' FP ops. At present the
182    /// only blessed op is the fmuladd intrinsic. In the future more blessed ops
183    /// may be added.
184    /// Strict mode - allow fusion only if/when it can be proven that the excess
185    /// precision won't effect the result.
186    ///
187    /// Note: This option only controls formation of fused ops by the
188    /// optimizers.  Fused operations that are explicitly specified (e.g. FMA
189    /// via the llvm.fma.* intrinsic) will always be honored, regardless of
190    /// the value of this option.
191    FPOpFusion::FPOpFusionMode AllowFPOpFusion;
192  };
193
194// Comparison operators:
195
196
197inline bool operator==(const TargetOptions &LHS,
198                       const TargetOptions &RHS) {
199#define ARE_EQUAL(X) LHS.X == RHS.X
200  return
201    ARE_EQUAL(UnsafeFPMath) &&
202    ARE_EQUAL(NoInfsFPMath) &&
203    ARE_EQUAL(NoNaNsFPMath) &&
204    ARE_EQUAL(HonorSignDependentRoundingFPMathOption) &&
205    ARE_EQUAL(UseSoftFloat) &&
206    ARE_EQUAL(NoZerosInBSS) &&
207    ARE_EQUAL(JITEmitDebugInfo) &&
208    ARE_EQUAL(JITEmitDebugInfoToDisk) &&
209    ARE_EQUAL(GuaranteedTailCallOpt) &&
210    ARE_EQUAL(DisableTailCalls) &&
211    ARE_EQUAL(StackAlignmentOverride) &&
212    ARE_EQUAL(EnableFastISel) &&
213    ARE_EQUAL(PositionIndependentExecutable) &&
214    ARE_EQUAL(EnableSegmentedStacks) &&
215    ARE_EQUAL(UseInitArray) &&
216    ARE_EQUAL(TrapFuncName) &&
217    ARE_EQUAL(FloatABIType) &&
218    ARE_EQUAL(AllowFPOpFusion);
219#undef ARE_EQUAL
220}
221
222inline bool operator!=(const TargetOptions &LHS,
223                       const TargetOptions &RHS) {
224  return !(LHS == RHS);
225}
226
227} // End llvm namespace
228
229#endif
230