LLVM  8.0.0svn
TargetOptions.h
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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 
19 
20 namespace llvm {
21  class MachineFunction;
22  class Module;
23 
24  namespace FloatABI {
25  enum ABIType {
26  Default, // Target-specific (either soft or hard depending on triple, etc).
27  Soft, // Soft float.
28  Hard // Hard float.
29  };
30  }
31 
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.
37  };
38  }
39 
40  namespace JumpTable {
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
48  };
49  }
50 
51  namespace ThreadModel {
52  enum Model {
53  POSIX, // POSIX Threads
54  Single // Single Threaded Environment
55  };
56  }
57 
58  namespace FPDenormal {
59  enum DenormalMode {
60  IEEE, // IEEE 754 denormal numbers
61  PreserveSign, // the sign of a flushed-to-zero number is preserved in
62  // the sign of 0
63  PositiveZero // denormals are flushed to positive zero
64  };
65  }
66 
67  enum class EABI {
68  Unknown,
69  Default, // Default means not specified
70  EABI4, // Target-specific (either 4, 5 or gnu depending on triple).
71  EABI5,
72  GNU
73  };
74 
75  /// Identify a debugger for "tuning" the debug info.
76  ///
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.
88  ///
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).
97  };
98 
99  class TargetOptions {
100  public:
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), EnableGlobalISel(false), UseInitArray(false),
108  DisableIntegratedAS(false), RelaxELFRelocations(false),
109  FunctionSections(false), DataSections(false),
110  UniqueSectionNames(true), TrapUnreachable(false),
111  NoTrapAfterNoreturn(false), EmulatedTLS(false),
112  ExplicitEmulatedTLS(false), EnableIPRA(false),
113  EmitStackSizeSection(false), EnableMachineOutliner(false),
114  SupportsDefaultOutlining(false), EmitAddrsig(false) {}
115 
116  /// PrintMachineCode - This flag is enabled when the -print-machineinstrs
117  /// option is specified on the command line, and should enable debugging
118  /// output from the code generator.
119  unsigned PrintMachineCode : 1;
120 
121  /// DisableFramePointerElim - This returns true if frame pointer elimination
122  /// optimization should be disabled for the given machine function.
123  bool DisableFramePointerElim(const MachineFunction &MF) const;
124 
125  /// UnsafeFPMath - This flag is enabled when the
126  /// -enable-unsafe-fp-math flag is specified on the command line. When
127  /// this flag is off (the default), the code generator is not allowed to
128  /// produce results that are "less precise" than IEEE allows. This includes
129  /// use of X86 instructions like FSIN and FCOS instead of libcalls.
130  unsigned UnsafeFPMath : 1;
131 
132  /// NoInfsFPMath - This flag is enabled when the
133  /// -enable-no-infs-fp-math flag is specified on the command line. When
134  /// this flag is off (the default), the code generator is not allowed to
135  /// assume the FP arithmetic arguments and results are never +-Infs.
136  unsigned NoInfsFPMath : 1;
137 
138  /// NoNaNsFPMath - This flag is enabled when the
139  /// -enable-no-nans-fp-math flag is specified on the command line. When
140  /// this flag is off (the default), the code generator is not allowed to
141  /// assume the FP arithmetic arguments and results are never NaNs.
142  unsigned NoNaNsFPMath : 1;
143 
144  /// NoTrappingFPMath - This flag is enabled when the
145  /// -enable-no-trapping-fp-math is specified on the command line. This
146  /// specifies that there are no trap handlers to handle exceptions.
147  unsigned NoTrappingFPMath : 1;
148 
149  /// NoSignedZerosFPMath - This flag is enabled when the
150  /// -enable-no-signed-zeros-fp-math is specified on the command line. This
151  /// specifies that optimizations are allowed to treat the sign of a zero
152  /// argument or result as insignificant.
153  unsigned NoSignedZerosFPMath : 1;
154 
155  /// HonorSignDependentRoundingFPMath - This returns true when the
156  /// -enable-sign-dependent-rounding-fp-math is specified. If this returns
157  /// false (the default), the code generator is allowed to assume that the
158  /// rounding behavior is the default (round-to-zero for all floating point
159  /// to integer conversions, and round-to-nearest for all other arithmetic
160  /// truncations). If this is enabled (set to true), the code generator must
161  /// assume that the rounding mode may dynamically change.
163  bool HonorSignDependentRoundingFPMath() const;
164 
165  /// NoZerosInBSS - By default some codegens place zero-initialized data to
166  /// .bss section. This flag disables such behaviour (necessary, e.g. for
167  /// crt*.o compiling).
168  unsigned NoZerosInBSS : 1;
169 
170  /// GuaranteedTailCallOpt - This flag is enabled when -tailcallopt is
171  /// specified on the commandline. When the flag is on, participating targets
172  /// will perform tail call optimization on all calls which use the fastcc
173  /// calling convention and which satisfy certain target-independent
174  /// criteria (being at the end of a function, having the same return type
175  /// as their parent function, etc.), using an alternate ABI if necessary.
176  unsigned GuaranteedTailCallOpt : 1;
177 
178  /// StackAlignmentOverride - Override default stack alignment for target.
179  unsigned StackAlignmentOverride = 0;
180 
181  /// StackSymbolOrdering - When true, this will allow CodeGen to order
182  /// the local stack symbols (for code size, code locality, or any other
183  /// heuristics). When false, the local symbols are left in whatever order
184  /// they were generated. Default is true.
185  unsigned StackSymbolOrdering : 1;
186 
187  /// EnableFastISel - This flag enables fast-path instruction selection
188  /// which trades away generated code quality in favor of reducing
189  /// compile time.
190  unsigned EnableFastISel : 1;
191 
192  /// EnableGlobalISel - This flag enables global instruction selection.
193  unsigned EnableGlobalISel : 1;
194 
195  /// UseInitArray - Use .init_array instead of .ctors for static
196  /// constructors.
197  unsigned UseInitArray : 1;
198 
199  /// Disable the integrated assembler.
200  unsigned DisableIntegratedAS : 1;
201 
202  /// Compress DWARF debug sections.
204 
205  unsigned RelaxELFRelocations : 1;
206 
207  /// Emit functions into separate sections.
208  unsigned FunctionSections : 1;
209 
210  /// Emit data into separate sections.
211  unsigned DataSections : 1;
212 
213  unsigned UniqueSectionNames : 1;
214 
215  /// Emit target-specific trap instruction for 'unreachable' IR instructions.
216  unsigned TrapUnreachable : 1;
217 
218  /// Do not emit a trap instruction for 'unreachable' IR instructions behind
219  /// noreturn calls, even if TrapUnreachable is true.
220  unsigned NoTrapAfterNoreturn : 1;
221 
222  /// EmulatedTLS - This flag enables emulated TLS model, using emutls
223  /// function in the runtime library..
224  unsigned EmulatedTLS : 1;
225 
226  /// Whether -emulated-tls or -no-emulated-tls is set.
227  unsigned ExplicitEmulatedTLS : 1;
228 
229  /// This flag enables InterProcedural Register Allocation (IPRA).
230  unsigned EnableIPRA : 1;
231 
232  /// Emit section containing metadata on function stack sizes.
233  unsigned EmitStackSizeSection : 1;
234 
235  /// Enables the MachineOutliner pass.
236  unsigned EnableMachineOutliner : 1;
237 
238  /// Set if the target supports default outlining behaviour.
240 
241  /// Emit address-significance table.
242  unsigned EmitAddrsig : 1;
243 
244  /// FloatABIType - This setting is set by -float-abi=xxx option is specfied
245  /// on the command line. This setting may either be Default, Soft, or Hard.
246  /// Default selects the target's default behavior. Soft selects the ABI for
247  /// software floating point, but does not indicate that FP hardware may not
248  /// be used. Such a combination is unfortunately popular (e.g.
249  /// arm-apple-darwin). Hard presumes that the normal FP ABI is used.
251 
252  /// AllowFPOpFusion - This flag is set by the -fuse-fp-ops=xxx option.
253  /// This controls the creation of fused FP ops that store intermediate
254  /// results in higher precision than IEEE allows (E.g. FMAs).
255  ///
256  /// Fast mode - allows formation of fused FP ops whenever they're
257  /// profitable.
258  /// Standard mode - allow fusion only for 'blessed' FP ops. At present the
259  /// only blessed op is the fmuladd intrinsic. In the future more blessed ops
260  /// may be added.
261  /// Strict mode - allow fusion only if/when it can be proven that the excess
262  /// precision won't effect the result.
263  ///
264  /// Note: This option only controls formation of fused ops by the
265  /// optimizers. Fused operations that are explicitly specified (e.g. FMA
266  /// via the llvm.fma.* intrinsic) will always be honored, regardless of
267  /// the value of this option.
269 
270  /// ThreadModel - This flag specifies the type of threading model to assume
271  /// for things like atomics
273 
274  /// EABIVersion - This flag specifies the EABI version
275  EABI EABIVersion = EABI::Default;
276 
277  /// Which debugger to tune for.
279 
280  /// FPDenormalMode - This flags specificies which denormal numbers the code
281  /// is permitted to require.
283 
284  /// What exception model to use
286 
287  /// Machine level options.
289  };
290 
291 } // End llvm namespace
292 
293 #endif
unsigned StackSymbolOrdering
StackSymbolOrdering - When true, this will allow CodeGen to order the local stack symbols (for code s...
unsigned NoTrappingFPMath
NoTrappingFPMath - This flag is enabled when the -enable-no-trapping-fp-math is specified on the comm...
unsigned PrintMachineCode
PrintMachineCode - This flag is enabled when the -print-machineinstrs option is specified on the comm...
MCTargetOptions MCOptions
Machine level options.
Compute iterated dominance frontiers using a linear time algorithm.
Definition: AllocatorList.h:24
unsigned EnableFastISel
EnableFastISel - This flag enables fast-path instruction selection which trades away generated code q...
unsigned DataSections
Emit data into separate sections.
unsigned EnableMachineOutliner
Enables the MachineOutliner pass.
block Block Frequency true
unsigned NoTrapAfterNoreturn
Do not emit a trap instruction for 'unreachable' IR instructions behind noreturn calls, even if TrapUnreachable is true.
DebuggerKind
Identify a debugger for "tuning" the debug info.
Definition: TargetOptions.h:92
cl::opt< bool > EnableIPRA("enable-ipra", cl::init(false), cl::Hidden, cl::desc("Enable interprocedural register allocation " "to reduce load/store at procedure calls."))
unsigned DisableIntegratedAS
Disable the integrated assembler.
unsigned EnableIPRA
This flag enables InterProcedural Register Allocation (IPRA).
unsigned NoNaNsFPMath
NoNaNsFPMath - This flag is enabled when the -enable-no-nans-fp-math flag is specified on the command...
static cl::opt< RunOutliner > EnableMachineOutliner("enable-machine-outliner", cl::desc("Enable the machine outliner"), cl::Hidden, cl::ValueOptional, cl::init(TargetDefault), cl::values(clEnumValN(AlwaysOutline, "always", "Run on all functions guaranteed to be beneficial"), clEnumValN(NeverOutline, "never", "Disable all outlining"), clEnumValN(AlwaysOutline, "", "")))
unsigned FunctionSections
Emit functions into separate sections.
unsigned UniqueSectionNames
unsigned SupportsDefaultOutlining
Set if the target supports default outlining behaviour.
unsigned EnableGlobalISel
EnableGlobalISel - This flag enables global instruction selection.
unsigned UnsafeFPMath
UnsafeFPMath - This flag is enabled when the -enable-unsafe-fp-math flag is specified on the command ...
unsigned ExplicitEmulatedTLS
Whether -emulated-tls or -no-emulated-tls is set.
unsigned EmitStackSizeSection
Emit section containing metadata on function stack sizes.
unsigned GuaranteedTailCallOpt
GuaranteedTailCallOpt - This flag is enabled when -tailcallopt is specified on the commandline...
unsigned NoInfsFPMath
NoInfsFPMath - This flag is enabled when the -enable-no-infs-fp-math flag is specified on the command...
unsigned NoZerosInBSS
NoZerosInBSS - By default some codegens place zero-initialized data to .bss section.
unsigned UseInitArray
UseInitArray - Use .init_array instead of .ctors for static constructors.
unsigned EmitAddrsig
Emit address-significance table.
unsigned EmulatedTLS
EmulatedTLS - This flag enables emulated TLS model, using emutls function in the runtime library...
unsigned RelaxELFRelocations
unsigned HonorSignDependentRoundingFPMathOption
HonorSignDependentRoundingFPMath - This returns true when the -enable-sign-dependent-rounding-fp-math...
ExceptionHandling
unsigned NoSignedZerosFPMath
NoSignedZerosFPMath - This flag is enabled when the -enable-no-signed-zeros-fp-math is specified on t...
unsigned TrapUnreachable
Emit target-specific trap instruction for &#39;unreachable&#39; IR instructions.
DebugCompressionType