ARMSubtarget.h revision a7603982dbf9e240ecc7ed6eddcd1cdb868107ac 
1//=====---- ARMSubtarget.h - Define Subtarget for the ARM -----*- 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 declares the ARM specific subclass of TargetSubtargetInfo.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef ARMSUBTARGET_H
15#define ARMSUBTARGET_H
16
17#include "llvm/Target/TargetSubtargetInfo.h"
18#include "llvm/MC/MCInstrItineraries.h"
19#include "llvm/ADT/Triple.h"
20#include <string>
21
22#define GET_SUBTARGETINFO_HEADER
23#include "ARMGenSubtarget.inc"
24
25namespace llvm {
26class GlobalValue;
27
28class ARMSubtarget : public ARMGenSubtargetInfo {
29protected:
30  enum ARMArchEnum {
31    V4, V4T, V5T, V5TE, V6, V6M, V6T2, V7A, V7M, V7EM
32  };
33
34  enum ARMProcFamilyEnum {
35    Others, CortexA8, CortexA9
36  };
37
38  enum ARMFPEnum {
39    None, VFPv2, VFPv3, NEON
40  };
41
42  enum ThumbTypeEnum {
43    Thumb1,
44    Thumb2
45  };
46
47  /// ARMArchVersion - ARM architecture version: V4, V4T (base), V5T, V5TE,
48  /// V6, V6T2, V7A, V7M, V7EM.
49  ARMArchEnum ARMArchVersion;
50
51  /// ARMProcFamily - ARM processor family: Cortex-A8, Cortex-A9, and others.
52  ARMProcFamilyEnum ARMProcFamily;
53
54  /// ARMFPUType - Floating Point Unit type.
55  ARMFPEnum ARMFPUType;
56
57  /// UseNEONForSinglePrecisionFP - if the NEONFP attribute has been
58  /// specified. Use the method useNEONForSinglePrecisionFP() to
59  /// determine if NEON should actually be used.
60  bool UseNEONForSinglePrecisionFP;
61
62  /// SlowFPVMLx - If the VFP2 / NEON instructions are available, indicates
63  /// whether the FP VML[AS] instructions are slow (if so, don't use them).
64  bool SlowFPVMLx;
65
66  /// HasVMLxForwarding - If true, NEON has special multiplier accumulator
67  /// forwarding to allow mul + mla being issued back to back.
68  bool HasVMLxForwarding;
69
70  /// SlowFPBrcc - True if floating point compare + branch is slow.
71  bool SlowFPBrcc;
72
73  /// IsThumb - True if we are in thumb mode, false if in ARM mode.
74  bool IsThumb;
75
76  /// ThumbMode - Indicates supported Thumb version.
77  ThumbTypeEnum ThumbMode;
78
79  /// NoARM - True if subtarget does not support ARM mode execution.
80  bool NoARM;
81
82  /// PostRAScheduler - True if using post-register-allocation scheduler.
83  bool PostRAScheduler;
84
85  /// IsR9Reserved - True if R9 is a not available as general purpose register.
86  bool IsR9Reserved;
87
88  /// UseMovt - True if MOVT / MOVW pairs are used for materialization of 32-bit
89  /// imms (including global addresses).
90  bool UseMovt;
91
92  /// HasFP16 - True if subtarget supports half-precision FP (We support VFP+HF
93  /// only so far)
94  bool HasFP16;
95
96  /// HasD16 - True if subtarget is limited to 16 double precision
97  /// FP registers for VFPv3.
98  bool HasD16;
99
100  /// HasHardwareDivide - True if subtarget supports [su]div
101  bool HasHardwareDivide;
102
103  /// HasT2ExtractPack - True if subtarget supports thumb2 extract/pack
104  /// instructions.
105  bool HasT2ExtractPack;
106
107  /// HasDataBarrier - True if the subtarget supports DMB / DSB data barrier
108  /// instructions.
109  bool HasDataBarrier;
110
111  /// Pref32BitThumb - If true, codegen would prefer 32-bit Thumb instructions
112  /// over 16-bit ones.
113  bool Pref32BitThumb;
114
115  /// AvoidCPSRPartialUpdate - If true, codegen would avoid using instructions
116  /// that partially update CPSR and add false dependency on the previous
117  /// CPSR setting instruction.
118  bool AvoidCPSRPartialUpdate;
119
120  /// HasMPExtension - True if the subtarget supports Multiprocessing
121  /// extension (ARMv7 only).
122  bool HasMPExtension;
123
124  /// FPOnlySP - If true, the floating point unit only supports single
125  /// precision.
126  bool FPOnlySP;
127
128  /// AllowsUnalignedMem - If true, the subtarget allows unaligned memory
129  /// accesses for some types.  For details, see
130  /// ARMTargetLowering::allowsUnalignedMemoryAccesses().
131  bool AllowsUnalignedMem;
132
133  /// Thumb2DSP - If true, the subtarget supports the v7 DSP (saturating arith
134  /// and such) instructions in Thumb2 code.
135  bool Thumb2DSP;
136
137  /// stackAlignment - The minimum alignment known to hold of the stack frame on
138  /// entry to the function and which must be maintained by every function.
139  unsigned stackAlignment;
140
141  /// CPUString - String name of used CPU.
142  std::string CPUString;
143
144  /// TargetTriple - What processor and OS we're targeting.
145  Triple TargetTriple;
146
147  /// Selected instruction itineraries (one entry per itinerary class.)
148  InstrItineraryData InstrItins;
149
150 public:
151  enum {
152    isELF, isDarwin
153  } TargetType;
154
155  enum {
156    ARM_ABI_APCS,
157    ARM_ABI_AAPCS // ARM EABI
158  } TargetABI;
159
160  /// This constructor initializes the data members to match that
161  /// of the specified triple.
162  ///
163  ARMSubtarget(const std::string &TT, const std::string &CPU,
164               const std::string &FS, bool isThumb);
165
166  /// getMaxInlineSizeThreshold - Returns the maximum memset / memcpy size
167  /// that still makes it profitable to inline the call.
168  unsigned getMaxInlineSizeThreshold() const {
169    // FIXME: For now, we don't lower memcpy's to loads / stores for Thumb1.
170    // Change this once Thumb1 ldmia / stmia support is added.
171    return isThumb1Only() ? 0 : 64;
172  }
173  /// ParseSubtargetFeatures - Parses features string setting specified
174  /// subtarget options.  Definition of function is auto generated by tblgen.
175  void ParseSubtargetFeatures(const std::string &FS, const std::string &CPU);
176
177  void computeIssueWidth();
178
179  bool hasV4TOps()  const { return ARMArchVersion >= V4T;  }
180  bool hasV5TOps()  const { return ARMArchVersion >= V5T;  }
181  bool hasV5TEOps() const { return ARMArchVersion >= V5TE; }
182  bool hasV6Ops()   const { return ARMArchVersion >= V6;   }
183  bool hasV6T2Ops() const { return ARMArchVersion >= V6T2; }
184  bool hasV7Ops()   const { return ARMArchVersion >= V7A;  }
185
186  bool isCortexA8() const { return ARMProcFamily == CortexA8; }
187  bool isCortexA9() const { return ARMProcFamily == CortexA9; }
188
189  bool hasARMOps() const { return !NoARM; }
190
191  bool hasVFP2() const { return ARMFPUType >= VFPv2; }
192  bool hasVFP3() const { return ARMFPUType >= VFPv3; }
193  bool hasNEON() const { return ARMFPUType >= NEON;  }
194  bool useNEONForSinglePrecisionFP() const {
195    return hasNEON() && UseNEONForSinglePrecisionFP; }
196  bool hasDivide() const { return HasHardwareDivide; }
197  bool hasT2ExtractPack() const { return HasT2ExtractPack; }
198  bool hasDataBarrier() const { return HasDataBarrier; }
199  bool useFPVMLx() const { return !SlowFPVMLx; }
200  bool hasVMLxForwarding() const { return HasVMLxForwarding; }
201  bool isFPBrccSlow() const { return SlowFPBrcc; }
202  bool isFPOnlySP() const { return FPOnlySP; }
203  bool prefers32BitThumb() const { return Pref32BitThumb; }
204  bool avoidCPSRPartialUpdate() const { return AvoidCPSRPartialUpdate; }
205  bool hasMPExtension() const { return HasMPExtension; }
206  bool hasThumb2DSP() const { return Thumb2DSP; }
207
208  bool hasFP16() const { return HasFP16; }
209  bool hasD16() const { return HasD16; }
210
211  const Triple &getTargetTriple() const { return TargetTriple; }
212
213  bool isTargetDarwin() const { return TargetTriple.isOSDarwin(); }
214  bool isTargetELF() const { return !isTargetDarwin(); }
215
216  bool isAPCS_ABI() const { return TargetABI == ARM_ABI_APCS; }
217  bool isAAPCS_ABI() const { return TargetABI == ARM_ABI_AAPCS; }
218
219  bool isThumb() const { return IsThumb; }
220  bool isThumb1Only() const { return IsThumb && (ThumbMode == Thumb1); }
221  bool isThumb2() const { return IsThumb && (ThumbMode == Thumb2); }
222  bool hasThumb2() const { return ThumbMode >= Thumb2; }
223
224  bool isR9Reserved() const { return IsR9Reserved; }
225
226  bool useMovt() const { return UseMovt && hasV6T2Ops(); }
227
228  bool allowsUnalignedMem() const { return AllowsUnalignedMem; }
229
230  const std::string & getCPUString() const { return CPUString; }
231
232  unsigned getMispredictionPenalty() const;
233
234  /// enablePostRAScheduler - True at 'More' optimization.
235  bool enablePostRAScheduler(CodeGenOpt::Level OptLevel,
236                             TargetSubtargetInfo::AntiDepBreakMode& Mode,
237                             RegClassVector& CriticalPathRCs) const;
238
239  /// getInstrItins - Return the instruction itineraies based on subtarget
240  /// selection.
241  const InstrItineraryData &getInstrItineraryData() const { return InstrItins; }
242
243  /// getStackAlignment - Returns the minimum alignment known to hold of the
244  /// stack frame on entry to the function and which must be maintained by every
245  /// function for this subtarget.
246  unsigned getStackAlignment() const { return stackAlignment; }
247
248  /// GVIsIndirectSymbol - true if the GV will be accessed via an indirect
249  /// symbol.
250  bool GVIsIndirectSymbol(const GlobalValue *GV, Reloc::Model RelocM) const;
251};
252} // End llvm namespace
253
254#endif  // ARMSUBTARGET_H
255