summaryrefslogtreecommitdiff
path: root/include/llvm/Target/TargetOptions.h
blob: d1a07d1480b47fc27517698a1f5cacb8eea12b2c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
//===-- llvm/Target/TargetOptions.h - Target Options ------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines command line option flags that are shared across various
// targets.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_TARGET_TARGETOPTIONS_H
#define LLVM_TARGET_TARGETOPTIONS_H

#include <string>

namespace llvm {
  class MachineFunction;
  class StringRef;

  // Possible float ABI settings. Used with FloatABIType in TargetOptions.h.
  namespace FloatABI {
    enum ABIType {
      Default, // Target-specific (either soft or hard depending on triple, etc).
      Soft, // Soft float.
      Hard  // Hard float.
    };
  }

  namespace FPOpFusion {
    enum FPOpFusionMode {
      Fast,     // Enable fusion of FP ops wherever it's profitable.
      Standard, // Only allow fusion of 'blessed' ops (currently just fmuladd).
      Strict    // Never fuse FP-ops.
    };
  }

  class TargetOptions {
  public:
    TargetOptions()
        : PrintMachineCode(false), NoFramePointerElim(false),
          NoFramePointerElimNonLeaf(false), LessPreciseFPMADOption(false),
          UnsafeFPMath(false), NoInfsFPMath(false),
          NoNaNsFPMath(false), HonorSignDependentRoundingFPMathOption(false),
          UseSoftFloat(false), NoZerosInBSS(false), JITExceptionHandling(false),
          JITEmitDebugInfo(false), JITEmitDebugInfoToDisk(false),
          GuaranteedTailCallOpt(false), DisableTailCalls(false),
          StackAlignmentOverride(0), RealignStack(true), EnableFastISel(false),
          PositionIndependentExecutable(false), EnableSegmentedStacks(false),
          UseInitArray(false), TrapFuncName(""), FloatABIType(FloatABI::Default),
          AllowFPOpFusion(FPOpFusion::Standard)
    {}

    /// PrintMachineCode - This flag is enabled when the -print-machineinstrs
    /// option is specified on the command line, and should enable debugging
    /// output from the code generator.
    unsigned PrintMachineCode : 1;

    /// NoFramePointerElim - This flag is enabled when the -disable-fp-elim is
    /// specified on the command line.  If the target supports the frame pointer
    /// elimination optimization, this option should disable it.
    unsigned NoFramePointerElim : 1;

    /// NoFramePointerElimNonLeaf - This flag is enabled when the
    /// -disable-non-leaf-fp-elim is specified on the command line. If the
    /// target supports the frame pointer elimination optimization, this option
    /// should disable it for non-leaf functions.
    unsigned NoFramePointerElimNonLeaf : 1;

    /// DisableFramePointerElim - This returns true if frame pointer elimination
    /// optimization should be disabled for the given machine function.
    bool DisableFramePointerElim(const MachineFunction &MF) const;

    /// LessPreciseFPMAD - This flag is enabled when the
    /// -enable-fp-mad is specified on the command line.  When this flag is off
    /// (the default), the code generator is not allowed to generate mad
    /// (multiply add) if the result is "less precise" than doing those
    /// operations individually.
    unsigned LessPreciseFPMADOption : 1;
    bool LessPreciseFPMAD() const;

    /// UnsafeFPMath - This flag is enabled when the
    /// -enable-unsafe-fp-math flag is specified on the command line.  When
    /// this flag is off (the default), the code generator is not allowed to
    /// produce results that are "less precise" than IEEE allows.  This includes
    /// use of X86 instructions like FSIN and FCOS instead of libcalls.
    /// UnsafeFPMath implies LessPreciseFPMAD.
    unsigned UnsafeFPMath : 1;

    /// NoInfsFPMath - This flag is enabled when the
    /// -enable-no-infs-fp-math flag is specified on the command line. When
    /// this flag is off (the default), the code generator is not allowed to
    /// assume the FP arithmetic arguments and results are never +-Infs.
    unsigned NoInfsFPMath : 1;

    /// NoNaNsFPMath - This flag is enabled when the
    /// -enable-no-nans-fp-math flag is specified on the command line. When
    /// this flag is off (the default), the code generator is not allowed to
    /// assume the FP arithmetic arguments and results are never NaNs.
    unsigned NoNaNsFPMath : 1;

    /// HonorSignDependentRoundingFPMath - This returns true when the
    /// -enable-sign-dependent-rounding-fp-math is specified.  If this returns
    /// false (the default), the code generator is allowed to assume that the
    /// rounding behavior is the default (round-to-zero for all floating point
    /// to integer conversions, and round-to-nearest for all other arithmetic
    /// truncations).  If this is enabled (set to true), the code generator must
    /// assume that the rounding mode may dynamically change.
    unsigned HonorSignDependentRoundingFPMathOption : 1;
    bool HonorSignDependentRoundingFPMath() const;

    /// UseSoftFloat - This flag is enabled when the -soft-float flag is
    /// specified on the command line.  When this flag is on, the code generator
    /// will generate libcalls to the software floating point library instead of
    /// target FP instructions.
    unsigned UseSoftFloat : 1;

    /// NoZerosInBSS - By default some codegens place zero-initialized data to
    /// .bss section. This flag disables such behaviour (necessary, e.g. for
    /// crt*.o compiling).
    unsigned NoZerosInBSS : 1;

    /// JITExceptionHandling - This flag indicates that the JIT should emit
    /// exception handling information.
    unsigned JITExceptionHandling : 1;

    /// JITEmitDebugInfo - This flag indicates that the JIT should try to emit
    /// debug information and notify a debugger about it.
    unsigned JITEmitDebugInfo : 1;

    /// JITEmitDebugInfoToDisk - This flag indicates that the JIT should write
    /// the object files generated by the JITEmitDebugInfo flag to disk.  This
    /// flag is hidden and is only for debugging the debug info.
    unsigned JITEmitDebugInfoToDisk : 1;

    /// GuaranteedTailCallOpt - This flag is enabled when -tailcallopt is
    /// specified on the commandline. When the flag is on, participating targets
    /// will perform tail call optimization on all calls which use the fastcc
    /// calling convention and which satisfy certain target-independent
    /// criteria (being at the end of a function, having the same return type
    /// as their parent function, etc.), using an alternate ABI if necessary.
    unsigned GuaranteedTailCallOpt : 1;

    /// DisableTailCalls - This flag controls whether we will use tail calls.
    /// Disabling them may be useful to maintain a correct call stack.
    unsigned DisableTailCalls : 1;

    /// StackAlignmentOverride - Override default stack alignment for target.
    unsigned StackAlignmentOverride;

    /// RealignStack - This flag indicates whether the stack should be
    /// automatically realigned, if needed.
    unsigned RealignStack : 1;

    /// EnableFastISel - This flag enables fast-path instruction selection
    /// which trades away generated code quality in favor of reducing
    /// compile time.
    unsigned EnableFastISel : 1;

    /// PositionIndependentExecutable - This flag indicates whether the code
    /// will eventually be linked into a single executable, despite the PIC
    /// relocation model being in use. It's value is undefined (and irrelevant)
    /// if the relocation model is anything other than PIC.
    unsigned PositionIndependentExecutable : 1;

    unsigned EnableSegmentedStacks : 1;

    /// UseInitArray - Use .init_array instead of .ctors for static
    /// constructors.
    unsigned UseInitArray : 1;

    /// getTrapFunctionName - If this returns a non-empty string, this means
    /// isel should lower Intrinsic::trap to a call to the specified function
    /// name instead of an ISD::TRAP node.
    std::string TrapFuncName;
    StringRef getTrapFunctionName() const;

    /// FloatABIType - This setting is set by -float-abi=xxx option is specfied
    /// on the command line. This setting may either be Default, Soft, or Hard.
    /// Default selects the target's default behavior. Soft selects the ABI for
    /// UseSoftFloat, but does not indicate that FP hardware may not be used.
    /// Such a combination is unfortunately popular (e.g. arm-apple-darwin).
    /// Hard presumes that the normal FP ABI is used.
    FloatABI::ABIType FloatABIType;

    /// AllowFPOpFusion - This flag is set by the -fuse-fp-ops=xxx option.
    /// This controls the creation of fused FP ops that store intermediate
    /// results in higher precision than IEEE allows (E.g. FMAs).
    ///
    /// Fast mode - allows formation of fused FP ops whenever they're
    /// profitable.
    /// Standard mode - allow fusion only for 'blessed' FP ops. At present the
    /// only blessed op is the fmuladd intrinsic. In the future more blessed ops
    /// may be added.
    /// Strict mode - allow fusion only if/when it can be proven that the excess
    /// precision won't effect the result.
    ///
    /// Note: This option only controls formation of fused ops by the optimizers.
    /// Fused operations that are explicitly specified (e.g. FMA via the
    /// llvm.fma.* intrinsic) will always be honored, regardless of the value of
    /// this option.
    FPOpFusion::FPOpFusionMode AllowFPOpFusion;

  };
} // End llvm namespace

#endif