TargetOptions.h revision b3fe88f8379c4c4193d5d84267ae1a304437f8fa 
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 of hard depending on triple, etc).
28      Soft, // Soft float.
29      Hard  // Hard float.
30    };
31  }
32
33  /// StrongPHIElim - This flag enables more aggressive PHI elimination
34  /// wth earlier copy coalescing.
35  extern bool StrongPHIElim;
36
37  class TargetOptions {
38  public:
39    TargetOptions()
40        : PrintMachineCode(false), NoFramePointerElim(false),
41          NoFramePointerElimNonLeaf(false), LessPreciseFPMADOption(false),
42          NoExcessFPPrecision(false), UnsafeFPMath(false), NoInfsFPMath(false),
43          NoNaNsFPMath(false), HonorSignDependentRoundingFPMathOption(false),
44          UseSoftFloat(false), NoZerosInBSS(false), JITExceptionHandling(false),
45          JITEmitDebugInfo(false), JITEmitDebugInfoToDisk(false),
46          GuaranteedTailCallOpt(false), StackAlignmentOverride(0),
47          RealignStack(true), DisableJumpTables(false), EnableFastISel(false),
48          EnableSegmentedStacks(false), TrapFuncName(""),
49          FloatABIType(FloatABI::Default)
50    {}
51
52    /// PrintMachineCode - This flag is enabled when the -print-machineinstrs
53    /// option is specified on the command line, and should enable debugging
54    /// output from the code generator.
55    unsigned PrintMachineCode : 1;
56
57    /// NoFramePointerElim - This flag is enabled when the -disable-fp-elim is
58    /// specified on the command line.  If the target supports the frame pointer
59    /// elimination optimization, this option should disable it.
60    unsigned NoFramePointerElim : 1;
61
62    /// NoFramePointerElimNonLeaf - This flag is enabled when the
63    /// -disable-non-leaf-fp-elim is specified on the command line. If the
64    /// target supports the frame pointer elimination optimization, this option
65    /// should disable it for non-leaf functions.
66    unsigned NoFramePointerElimNonLeaf : 1;
67
68    /// DisableFramePointerElim - This returns true if frame pointer elimination
69    /// optimization should be disabled for the given machine function.
70    bool DisableFramePointerElim(const MachineFunction &MF) const;
71
72    /// LessPreciseFPMAD - This flag is enabled when the
73    /// -enable-fp-mad is specified on the command line.  When this flag is off
74    /// (the default), the code generator is not allowed to generate mad
75    /// (multiply add) if the result is "less precise" than doing those
76    /// operations individually.
77    unsigned LessPreciseFPMADOption : 1;
78    bool LessPreciseFPMAD() const;
79
80    /// NoExcessFPPrecision - This flag is enabled when the
81    /// -disable-excess-fp-precision flag is specified on the command line.
82    /// When this flag is off (the default), the code generator is allowed to
83    /// produce results that are "more precise" than IEEE allows.  This includes
84    /// use of FMA-like operations and use of the X86 FP registers without
85    /// rounding all over the place.
86    unsigned NoExcessFPPrecision : 1;
87
88    /// UnsafeFPMath - This flag is enabled when the
89    /// -enable-unsafe-fp-math flag is specified on the command line.  When
90    /// this flag is off (the default), the code generator is not allowed to
91    /// produce results that are "less precise" than IEEE allows.  This includes
92    /// use of X86 instructions like FSIN and FCOS instead of libcalls.
93    /// UnsafeFPMath implies LessPreciseFPMAD.
94    unsigned UnsafeFPMath : 1;
95
96    /// NoInfsFPMath - This flag is enabled when the
97    /// -enable-no-infs-fp-math flag is specified on the command line. When
98    /// this flag is off (the default), the code generator is not allowed to
99    /// assume the FP arithmetic arguments and results are never +-Infs.
100    unsigned NoInfsFPMath : 1;
101
102    /// NoNaNsFPMath - This flag is enabled when the
103    /// -enable-no-nans-fp-math flag is specified on the command line. When
104    /// this flag is off (the default), the code generator is not allowed to
105    /// assume the FP arithmetic arguments and results are never NaNs.
106    unsigned NoNaNsFPMath : 1;
107
108    /// HonorSignDependentRoundingFPMath - This returns true when the
109    /// -enable-sign-dependent-rounding-fp-math is specified.  If this returns
110    /// false (the default), the code generator is allowed to assume that the
111    /// rounding behavior is the default (round-to-zero for all floating point
112    /// to integer conversions, and round-to-nearest for all other arithmetic
113    /// truncations).  If this is enabled (set to true), the code generator must
114    /// assume that the rounding mode may dynamically change.
115    unsigned HonorSignDependentRoundingFPMathOption : 1;
116    bool HonorSignDependentRoundingFPMath() const;
117
118    /// UseSoftFloat - This flag is enabled when the -soft-float flag is
119    /// specified on the command line.  When this flag is on, the code generator
120    /// will generate libcalls to the software floating point library instead of
121    /// target FP instructions.
122    unsigned UseSoftFloat : 1;
123
124    /// NoZerosInBSS - By default some codegens place zero-initialized data to
125    /// .bss section. This flag disables such behaviour (necessary, e.g. for
126    /// crt*.o compiling).
127    unsigned NoZerosInBSS : 1;
128
129    /// JITExceptionHandling - This flag indicates that the JIT should emit
130    /// exception handling information.
131    unsigned JITExceptionHandling : 1;
132
133    /// JITEmitDebugInfo - This flag indicates that the JIT should try to emit
134    /// debug information and notify a debugger about it.
135    unsigned JITEmitDebugInfo : 1;
136
137    /// JITEmitDebugInfoToDisk - This flag indicates that the JIT should write
138    /// the object files generated by the JITEmitDebugInfo flag to disk.  This
139    /// flag is hidden and is only for debugging the debug info.
140    unsigned JITEmitDebugInfoToDisk : 1;
141
142    /// GuaranteedTailCallOpt - This flag is enabled when -tailcallopt is
143    /// specified on the commandline. When the flag is on, participating targets
144    /// will perform tail call optimization on all calls which use the fastcc
145    /// calling convention and which satisfy certain target-independent
146    /// criteria (being at the end of a function, having the same return type
147    /// as their parent function, etc.), using an alternate ABI if necessary.
148    unsigned GuaranteedTailCallOpt : 1;
149
150    /// StackAlignmentOverride - Override default stack alignment for target.
151    unsigned StackAlignmentOverride;
152
153    /// RealignStack - This flag indicates whether the stack should be
154    /// automatically realigned, if needed.
155    unsigned RealignStack : 1;
156
157    /// DisableJumpTables - This flag indicates jump tables should not be
158    /// generated.
159    unsigned DisableJumpTables : 1;
160
161    /// EnableFastISel - This flag enables fast-path instruction selection
162    /// which trades away generated code quality in favor of reducing
163    /// compile time.
164    unsigned EnableFastISel : 1;
165
166    unsigned EnableSegmentedStacks : 1;
167
168    /// getTrapFunctionName - If this returns a non-empty string, this means
169    /// isel should lower Intrinsic::trap to a call to the specified function
170    /// name instead of an ISD::TRAP node.
171    std::string TrapFuncName;
172    StringRef getTrapFunctionName() const;
173
174    /// FloatABIType - This setting is set by -float-abi=xxx option is specfied
175    /// on the command line. This setting may either be Default, Soft, or Hard.
176    /// Default selects the target's default behavior. Soft selects the ABI for
177    /// UseSoftFloat, but does not indicate that FP hardware may not be used.
178    /// Such a combination is unfortunately popular (e.g. arm-apple-darwin).
179    /// Hard presumes that the normal FP ABI is used.
180    FloatABI::ABIType FloatABIType;
181  };
182} // End llvm namespace
183
184#endif
185