1//===--- TargetInfo.h - Expose information about the target -----*- 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/// \file
11/// \brief Defines the clang::TargetInfo interface.
12///
13//===----------------------------------------------------------------------===//
14
15#ifndef LLVM_CLANG_BASIC_TARGETINFO_H
16#define LLVM_CLANG_BASIC_TARGETINFO_H
17
18#include "clang/Basic/AddressSpaces.h"
19#include "clang/Basic/LLVM.h"
20#include "clang/Basic/Specifiers.h"
21#include "clang/Basic/TargetCXXABI.h"
22#include "clang/Basic/TargetOptions.h"
23#include "clang/Basic/VersionTuple.h"
24#include "llvm/ADT/IntrusiveRefCntPtr.h"
25#include "llvm/ADT/StringMap.h"
26#include "llvm/ADT/StringRef.h"
27#include "llvm/ADT/StringSwitch.h"
28#include "llvm/ADT/Triple.h"
29#include "llvm/Support/DataTypes.h"
30#include <cassert>
31#include <string>
32#include <vector>
33
34namespace llvm {
35struct fltSemantics;
36}
37
38namespace clang {
39class DiagnosticsEngine;
40class LangOptions;
41class MacroBuilder;
42class SourceLocation;
43class SourceManager;
44
45namespace Builtin { struct Info; }
46
47/// \brief Exposes information about the current target.
48///
49class TargetInfo : public RefCountedBase<TargetInfo> {
50  std::shared_ptr<TargetOptions> TargetOpts;
51  llvm::Triple Triple;
52protected:
53  // Target values set by the ctor of the actual target implementation.  Default
54  // values are specified by the TargetInfo constructor.
55  bool BigEndian;
56  bool TLSSupported;
57  bool NoAsmVariants;  // True if {|} are normal characters.
58  unsigned char PointerWidth, PointerAlign;
59  unsigned char BoolWidth, BoolAlign;
60  unsigned char IntWidth, IntAlign;
61  unsigned char HalfWidth, HalfAlign;
62  unsigned char FloatWidth, FloatAlign;
63  unsigned char DoubleWidth, DoubleAlign;
64  unsigned char LongDoubleWidth, LongDoubleAlign;
65  unsigned char LargeArrayMinWidth, LargeArrayAlign;
66  unsigned char LongWidth, LongAlign;
67  unsigned char LongLongWidth, LongLongAlign;
68  unsigned char SuitableAlign;
69  unsigned char MinGlobalAlign;
70  unsigned char MaxAtomicPromoteWidth, MaxAtomicInlineWidth;
71  unsigned short MaxVectorAlign;
72  const char *DescriptionString;
73  const char *UserLabelPrefix;
74  const char *MCountName;
75  const llvm::fltSemantics *HalfFormat, *FloatFormat, *DoubleFormat,
76    *LongDoubleFormat;
77  unsigned char RegParmMax, SSERegParmMax;
78  TargetCXXABI TheCXXABI;
79  const LangAS::Map *AddrSpaceMap;
80
81  mutable StringRef PlatformName;
82  mutable VersionTuple PlatformMinVersion;
83
84  unsigned HasAlignMac68kSupport : 1;
85  unsigned RealTypeUsesObjCFPRet : 3;
86  unsigned ComplexLongDoubleUsesFP2Ret : 1;
87
88  // TargetInfo Constructor.  Default initializes all fields.
89  TargetInfo(const llvm::Triple &T);
90
91public:
92  /// \brief Construct a target for the given options.
93  ///
94  /// \param Opts - The options to use to initialize the target. The target may
95  /// modify the options to canonicalize the target feature information to match
96  /// what the backend expects.
97  static TargetInfo *
98  CreateTargetInfo(DiagnosticsEngine &Diags,
99                   const std::shared_ptr<TargetOptions> &Opts);
100
101  virtual ~TargetInfo();
102
103  /// \brief Retrieve the target options.
104  TargetOptions &getTargetOpts() const {
105    assert(TargetOpts && "Missing target options");
106    return *TargetOpts;
107  }
108
109  ///===---- Target Data Type Query Methods -------------------------------===//
110  enum IntType {
111    NoInt = 0,
112    SignedChar,
113    UnsignedChar,
114    SignedShort,
115    UnsignedShort,
116    SignedInt,
117    UnsignedInt,
118    SignedLong,
119    UnsignedLong,
120    SignedLongLong,
121    UnsignedLongLong
122  };
123
124  enum RealType {
125    NoFloat = 255,
126    Float = 0,
127    Double,
128    LongDouble
129  };
130
131  /// \brief The different kinds of __builtin_va_list types defined by
132  /// the target implementation.
133  enum BuiltinVaListKind {
134    /// typedef char* __builtin_va_list;
135    CharPtrBuiltinVaList = 0,
136
137    /// typedef void* __builtin_va_list;
138    VoidPtrBuiltinVaList,
139
140    /// __builtin_va_list as defind by the AArch64 ABI
141    /// http://infocenter.arm.com/help/topic/com.arm.doc.ihi0055a/IHI0055A_aapcs64.pdf
142    AArch64ABIBuiltinVaList,
143
144    /// __builtin_va_list as defined by the PNaCl ABI:
145    /// http://www.chromium.org/nativeclient/pnacl/bitcode-abi#TOC-Machine-Types
146    PNaClABIBuiltinVaList,
147
148    /// __builtin_va_list as defined by the Power ABI:
149    /// https://www.power.org
150    ///        /resources/downloads/Power-Arch-32-bit-ABI-supp-1.0-Embedded.pdf
151    PowerABIBuiltinVaList,
152
153    /// __builtin_va_list as defined by the x86-64 ABI:
154    /// http://www.x86-64.org/documentation/abi.pdf
155    X86_64ABIBuiltinVaList,
156
157    /// __builtin_va_list as defined by ARM AAPCS ABI
158    /// http://infocenter.arm.com
159    //        /help/topic/com.arm.doc.ihi0042d/IHI0042D_aapcs.pdf
160    AAPCSABIBuiltinVaList,
161
162    // typedef struct __va_list_tag
163    //   {
164    //     long __gpr;
165    //     long __fpr;
166    //     void *__overflow_arg_area;
167    //     void *__reg_save_area;
168    //   } va_list[1];
169    SystemZBuiltinVaList
170  };
171
172protected:
173  IntType SizeType, IntMaxType, UIntMaxType, PtrDiffType, IntPtrType, WCharType,
174          WIntType, Char16Type, Char32Type, Int64Type, SigAtomicType,
175          ProcessIDType;
176
177  /// \brief Whether Objective-C's built-in boolean type should be signed char.
178  ///
179  /// Otherwise, when this flag is not set, the normal built-in boolean type is
180  /// used.
181  unsigned UseSignedCharForObjCBool : 1;
182
183  /// Control whether the alignment of bit-field types is respected when laying
184  /// out structures. If true, then the alignment of the bit-field type will be
185  /// used to (a) impact the alignment of the containing structure, and (b)
186  /// ensure that the individual bit-field will not straddle an alignment
187  /// boundary.
188  unsigned UseBitFieldTypeAlignment : 1;
189
190  /// \brief Whether zero length bitfields (e.g., int : 0;) force alignment of
191  /// the next bitfield.
192  ///
193  /// If the alignment of the zero length bitfield is greater than the member
194  /// that follows it, `bar', `bar' will be aligned as the type of the
195  /// zero-length bitfield.
196  unsigned UseZeroLengthBitfieldAlignment : 1;
197
198  /// If non-zero, specifies a fixed alignment value for bitfields that follow
199  /// zero length bitfield, regardless of the zero length bitfield type.
200  unsigned ZeroLengthBitfieldBoundary;
201
202  /// \brief Specify if mangling based on address space map should be used or
203  /// not for language specific address spaces
204  bool UseAddrSpaceMapMangling;
205
206public:
207  IntType getSizeType() const { return SizeType; }
208  IntType getIntMaxType() const { return IntMaxType; }
209  IntType getUIntMaxType() const { return UIntMaxType; }
210  IntType getPtrDiffType(unsigned AddrSpace) const {
211    return AddrSpace == 0 ? PtrDiffType : getPtrDiffTypeV(AddrSpace);
212  }
213  IntType getIntPtrType() const { return IntPtrType; }
214  IntType getUIntPtrType() const {
215    return getIntTypeByWidth(getTypeWidth(IntPtrType), false);
216  }
217  IntType getWCharType() const { return WCharType; }
218  IntType getWIntType() const { return WIntType; }
219  IntType getChar16Type() const { return Char16Type; }
220  IntType getChar32Type() const { return Char32Type; }
221  IntType getInt64Type() const { return Int64Type; }
222  IntType getSigAtomicType() const { return SigAtomicType; }
223  IntType getProcessIDType() const { return ProcessIDType; }
224
225  /// \brief Return the width (in bits) of the specified integer type enum.
226  ///
227  /// For example, SignedInt -> getIntWidth().
228  unsigned getTypeWidth(IntType T) const;
229
230  /// \brief Return integer type with specified width.
231  IntType getIntTypeByWidth(unsigned BitWidth, bool IsSigned) const;
232
233  /// \brief Return the smallest integer type with at least the specified width.
234  IntType getLeastIntTypeByWidth(unsigned BitWidth, bool IsSigned) const;
235
236  /// \brief Return floating point type with specified width.
237  RealType getRealTypeByWidth(unsigned BitWidth) const;
238
239  /// \brief Return the alignment (in bits) of the specified integer type enum.
240  ///
241  /// For example, SignedInt -> getIntAlign().
242  unsigned getTypeAlign(IntType T) const;
243
244  /// \brief Returns true if the type is signed; false otherwise.
245  static bool isTypeSigned(IntType T);
246
247  /// \brief Return the width of pointers on this target, for the
248  /// specified address space.
249  uint64_t getPointerWidth(unsigned AddrSpace) const {
250    return AddrSpace == 0 ? PointerWidth : getPointerWidthV(AddrSpace);
251  }
252  uint64_t getPointerAlign(unsigned AddrSpace) const {
253    return AddrSpace == 0 ? PointerAlign : getPointerAlignV(AddrSpace);
254  }
255
256  /// \brief Return the size of '_Bool' and C++ 'bool' for this target, in bits.
257  unsigned getBoolWidth() const { return BoolWidth; }
258
259  /// \brief Return the alignment of '_Bool' and C++ 'bool' for this target.
260  unsigned getBoolAlign() const { return BoolAlign; }
261
262  unsigned getCharWidth() const { return 8; } // FIXME
263  unsigned getCharAlign() const { return 8; } // FIXME
264
265  /// \brief Return the size of 'signed short' and 'unsigned short' for this
266  /// target, in bits.
267  unsigned getShortWidth() const { return 16; } // FIXME
268
269  /// \brief Return the alignment of 'signed short' and 'unsigned short' for
270  /// this target.
271  unsigned getShortAlign() const { return 16; } // FIXME
272
273  /// getIntWidth/Align - Return the size of 'signed int' and 'unsigned int' for
274  /// this target, in bits.
275  unsigned getIntWidth() const { return IntWidth; }
276  unsigned getIntAlign() const { return IntAlign; }
277
278  /// getLongWidth/Align - Return the size of 'signed long' and 'unsigned long'
279  /// for this target, in bits.
280  unsigned getLongWidth() const { return LongWidth; }
281  unsigned getLongAlign() const { return LongAlign; }
282
283  /// getLongLongWidth/Align - Return the size of 'signed long long' and
284  /// 'unsigned long long' for this target, in bits.
285  unsigned getLongLongWidth() const { return LongLongWidth; }
286  unsigned getLongLongAlign() const { return LongLongAlign; }
287
288  /// \brief Determine whether the __int128 type is supported on this target.
289  virtual bool hasInt128Type() const { return getPointerWidth(0) >= 64; } // FIXME
290
291  /// \brief Return the alignment that is suitable for storing any
292  /// object with a fundamental alignment requirement.
293  unsigned getSuitableAlign() const { return SuitableAlign; }
294
295  /// getMinGlobalAlign - Return the minimum alignment of a global variable,
296  /// unless its alignment is explicitly reduced via attributes.
297  unsigned getMinGlobalAlign() const { return MinGlobalAlign; }
298
299  /// getWCharWidth/Align - Return the size of 'wchar_t' for this target, in
300  /// bits.
301  unsigned getWCharWidth() const { return getTypeWidth(WCharType); }
302  unsigned getWCharAlign() const { return getTypeAlign(WCharType); }
303
304  /// getChar16Width/Align - Return the size of 'char16_t' for this target, in
305  /// bits.
306  unsigned getChar16Width() const { return getTypeWidth(Char16Type); }
307  unsigned getChar16Align() const { return getTypeAlign(Char16Type); }
308
309  /// getChar32Width/Align - Return the size of 'char32_t' for this target, in
310  /// bits.
311  unsigned getChar32Width() const { return getTypeWidth(Char32Type); }
312  unsigned getChar32Align() const { return getTypeAlign(Char32Type); }
313
314  /// getHalfWidth/Align/Format - Return the size/align/format of 'half'.
315  unsigned getHalfWidth() const { return HalfWidth; }
316  unsigned getHalfAlign() const { return HalfAlign; }
317  const llvm::fltSemantics &getHalfFormat() const { return *HalfFormat; }
318
319  /// getFloatWidth/Align/Format - Return the size/align/format of 'float'.
320  unsigned getFloatWidth() const { return FloatWidth; }
321  unsigned getFloatAlign() const { return FloatAlign; }
322  const llvm::fltSemantics &getFloatFormat() const { return *FloatFormat; }
323
324  /// getDoubleWidth/Align/Format - Return the size/align/format of 'double'.
325  unsigned getDoubleWidth() const { return DoubleWidth; }
326  unsigned getDoubleAlign() const { return DoubleAlign; }
327  const llvm::fltSemantics &getDoubleFormat() const { return *DoubleFormat; }
328
329  /// getLongDoubleWidth/Align/Format - Return the size/align/format of 'long
330  /// double'.
331  unsigned getLongDoubleWidth() const { return LongDoubleWidth; }
332  unsigned getLongDoubleAlign() const { return LongDoubleAlign; }
333  const llvm::fltSemantics &getLongDoubleFormat() const {
334    return *LongDoubleFormat;
335  }
336
337  /// \brief Return the value for the C99 FLT_EVAL_METHOD macro.
338  virtual unsigned getFloatEvalMethod() const { return 0; }
339
340  // getLargeArrayMinWidth/Align - Return the minimum array size that is
341  // 'large' and its alignment.
342  unsigned getLargeArrayMinWidth() const { return LargeArrayMinWidth; }
343  unsigned getLargeArrayAlign() const { return LargeArrayAlign; }
344
345  /// \brief Return the maximum width lock-free atomic operation which will
346  /// ever be supported for the given target
347  unsigned getMaxAtomicPromoteWidth() const { return MaxAtomicPromoteWidth; }
348  /// \brief Return the maximum width lock-free atomic operation which can be
349  /// inlined given the supported features of the given target.
350  unsigned getMaxAtomicInlineWidth() const { return MaxAtomicInlineWidth; }
351
352  /// \brief Return the maximum vector alignment supported for the given target.
353  unsigned getMaxVectorAlign() const { return MaxVectorAlign; }
354
355  /// \brief Return the size of intmax_t and uintmax_t for this target, in bits.
356  unsigned getIntMaxTWidth() const {
357    return getTypeWidth(IntMaxType);
358  }
359
360  // Return the size of unwind_word for this target.
361  unsigned getUnwindWordWidth() const { return getPointerWidth(0); }
362
363  /// \brief Return the "preferred" register width on this target.
364  unsigned getRegisterWidth() const {
365    // Currently we assume the register width on the target matches the pointer
366    // width, we can introduce a new variable for this if/when some target wants
367    // it.
368    return PointerWidth;
369  }
370
371  /// \brief Returns the default value of the __USER_LABEL_PREFIX__ macro,
372  /// which is the prefix given to user symbols by default.
373  ///
374  /// On most platforms this is "_", but it is "" on some, and "." on others.
375  const char *getUserLabelPrefix() const {
376    return UserLabelPrefix;
377  }
378
379  /// \brief Returns the name of the mcount instrumentation function.
380  const char *getMCountName() const {
381    return MCountName;
382  }
383
384  /// \brief Check if the Objective-C built-in boolean type should be signed
385  /// char.
386  ///
387  /// Otherwise, if this returns false, the normal built-in boolean type
388  /// should also be used for Objective-C.
389  bool useSignedCharForObjCBool() const {
390    return UseSignedCharForObjCBool;
391  }
392  void noSignedCharForObjCBool() {
393    UseSignedCharForObjCBool = false;
394  }
395
396  /// \brief Check whether the alignment of bit-field types is respected
397  /// when laying out structures.
398  bool useBitFieldTypeAlignment() const {
399    return UseBitFieldTypeAlignment;
400  }
401
402  /// \brief Check whether zero length bitfields should force alignment of
403  /// the next member.
404  bool useZeroLengthBitfieldAlignment() const {
405    return UseZeroLengthBitfieldAlignment;
406  }
407
408  /// \brief Get the fixed alignment value in bits for a member that follows
409  /// a zero length bitfield.
410  unsigned getZeroLengthBitfieldBoundary() const {
411    return ZeroLengthBitfieldBoundary;
412  }
413
414  /// \brief Check whether this target support '\#pragma options align=mac68k'.
415  bool hasAlignMac68kSupport() const {
416    return HasAlignMac68kSupport;
417  }
418
419  /// \brief Return the user string for the specified integer type enum.
420  ///
421  /// For example, SignedShort -> "short".
422  static const char *getTypeName(IntType T);
423
424  /// \brief Return the constant suffix for the specified integer type enum.
425  ///
426  /// For example, SignedLong -> "L".
427  static const char *getTypeConstantSuffix(IntType T);
428
429  /// \brief Check whether the given real type should use the "fpret" flavor of
430  /// Objective-C message passing on this target.
431  bool useObjCFPRetForRealType(RealType T) const {
432    return RealTypeUsesObjCFPRet & (1 << T);
433  }
434
435  /// \brief Check whether _Complex long double should use the "fp2ret" flavor
436  /// of Objective-C message passing on this target.
437  bool useObjCFP2RetForComplexLongDouble() const {
438    return ComplexLongDoubleUsesFP2Ret;
439  }
440
441  /// \brief Specify if mangling based on address space map should be used or
442  /// not for language specific address spaces
443  bool useAddressSpaceMapMangling() const {
444    return UseAddrSpaceMapMangling;
445  }
446
447  ///===---- Other target property query methods --------------------------===//
448
449  /// \brief Appends the target-specific \#define values for this
450  /// target set to the specified buffer.
451  virtual void getTargetDefines(const LangOptions &Opts,
452                                MacroBuilder &Builder) const = 0;
453
454
455  /// Return information about target-specific builtins for
456  /// the current primary target, and info about which builtins are non-portable
457  /// across the current set of primary and secondary targets.
458  virtual void getTargetBuiltins(const Builtin::Info *&Records,
459                                 unsigned &NumRecords) const = 0;
460
461  /// The __builtin_clz* and __builtin_ctz* built-in
462  /// functions are specified to have undefined results for zero inputs, but
463  /// on targets that support these operations in a way that provides
464  /// well-defined results for zero without loss of performance, it is a good
465  /// idea to avoid optimizing based on that undef behavior.
466  virtual bool isCLZForZeroUndef() const { return true; }
467
468  /// \brief Returns the kind of __builtin_va_list type that should be used
469  /// with this target.
470  virtual BuiltinVaListKind getBuiltinVaListKind() const = 0;
471
472  /// \brief Returns whether the passed in string is a valid clobber in an
473  /// inline asm statement.
474  ///
475  /// This is used by Sema.
476  bool isValidClobber(StringRef Name) const;
477
478  /// \brief Returns whether the passed in string is a valid register name
479  /// according to GCC.
480  ///
481  /// This is used by Sema for inline asm statements.
482  bool isValidGCCRegisterName(StringRef Name) const;
483
484  /// \brief Returns the "normalized" GCC register name.
485  ///
486  /// For example, on x86 it will return "ax" when "eax" is passed in.
487  StringRef getNormalizedGCCRegisterName(StringRef Name) const;
488
489  struct ConstraintInfo {
490    enum {
491      CI_None = 0x00,
492      CI_AllowsMemory = 0x01,
493      CI_AllowsRegister = 0x02,
494      CI_ReadWrite = 0x04,       // "+r" output constraint (read and write).
495      CI_HasMatchingInput = 0x08 // This output operand has a matching input.
496    };
497    unsigned Flags;
498    int TiedOperand;
499
500    std::string ConstraintStr;  // constraint: "=rm"
501    std::string Name;           // Operand name: [foo] with no []'s.
502  public:
503    ConstraintInfo(StringRef ConstraintStr, StringRef Name)
504      : Flags(0), TiedOperand(-1), ConstraintStr(ConstraintStr.str()),
505      Name(Name.str()) {}
506
507    const std::string &getConstraintStr() const { return ConstraintStr; }
508    const std::string &getName() const { return Name; }
509    bool isReadWrite() const { return (Flags & CI_ReadWrite) != 0; }
510    bool allowsRegister() const { return (Flags & CI_AllowsRegister) != 0; }
511    bool allowsMemory() const { return (Flags & CI_AllowsMemory) != 0; }
512
513    /// \brief Return true if this output operand has a matching
514    /// (tied) input operand.
515    bool hasMatchingInput() const { return (Flags & CI_HasMatchingInput) != 0; }
516
517    /// \brief Return true if this input operand is a matching
518    /// constraint that ties it to an output operand.
519    ///
520    /// If this returns true then getTiedOperand will indicate which output
521    /// operand this is tied to.
522    bool hasTiedOperand() const { return TiedOperand != -1; }
523    unsigned getTiedOperand() const {
524      assert(hasTiedOperand() && "Has no tied operand!");
525      return (unsigned)TiedOperand;
526    }
527
528    void setIsReadWrite() { Flags |= CI_ReadWrite; }
529    void setAllowsMemory() { Flags |= CI_AllowsMemory; }
530    void setAllowsRegister() { Flags |= CI_AllowsRegister; }
531    void setHasMatchingInput() { Flags |= CI_HasMatchingInput; }
532
533    /// \brief Indicate that this is an input operand that is tied to
534    /// the specified output operand.
535    ///
536    /// Copy over the various constraint information from the output.
537    void setTiedOperand(unsigned N, ConstraintInfo &Output) {
538      Output.setHasMatchingInput();
539      Flags = Output.Flags;
540      TiedOperand = N;
541      // Don't copy Name or constraint string.
542    }
543  };
544
545  // validateOutputConstraint, validateInputConstraint - Checks that
546  // a constraint is valid and provides information about it.
547  // FIXME: These should return a real error instead of just true/false.
548  bool validateOutputConstraint(ConstraintInfo &Info) const;
549  bool validateInputConstraint(ConstraintInfo *OutputConstraints,
550                               unsigned NumOutputs,
551                               ConstraintInfo &info) const;
552  virtual bool validateInputSize(StringRef /*Constraint*/,
553                                 unsigned /*Size*/) const {
554    return true;
555  }
556  virtual bool validateConstraintModifier(StringRef /*Constraint*/,
557                                          const char /*Modifier*/,
558                                          unsigned /*Size*/) const {
559    return true;
560  }
561  bool resolveSymbolicName(const char *&Name,
562                           ConstraintInfo *OutputConstraints,
563                           unsigned NumOutputs, unsigned &Index) const;
564
565  // Constraint parm will be left pointing at the last character of
566  // the constraint.  In practice, it won't be changed unless the
567  // constraint is longer than one character.
568  virtual std::string convertConstraint(const char *&Constraint) const {
569    // 'p' defaults to 'r', but can be overridden by targets.
570    if (*Constraint == 'p')
571      return std::string("r");
572    return std::string(1, *Constraint);
573  }
574
575  /// \brief Returns a string of target-specific clobbers, in LLVM format.
576  virtual const char *getClobbers() const = 0;
577
578
579  /// \brief Returns the target triple of the primary target.
580  const llvm::Triple &getTriple() const {
581    return Triple;
582  }
583
584  const char *getTargetDescription() const {
585    assert(DescriptionString);
586    return DescriptionString;
587  }
588
589  struct GCCRegAlias {
590    const char * const Aliases[5];
591    const char * const Register;
592  };
593
594  struct AddlRegName {
595    const char * const Names[5];
596    const unsigned RegNum;
597  };
598
599  /// \brief Does this target support "protected" visibility?
600  ///
601  /// Any target which dynamic libraries will naturally support
602  /// something like "default" (meaning that the symbol is visible
603  /// outside this shared object) and "hidden" (meaning that it isn't)
604  /// visibilities, but "protected" is really an ELF-specific concept
605  /// with weird semantics designed around the convenience of dynamic
606  /// linker implementations.  Which is not to suggest that there's
607  /// consistent target-independent semantics for "default" visibility
608  /// either; the entire thing is pretty badly mangled.
609  virtual bool hasProtectedVisibility() const { return true; }
610
611  /// \brief An optional hook that targets can implement to perform semantic
612  /// checking on attribute((section("foo"))) specifiers.
613  ///
614  /// In this case, "foo" is passed in to be checked.  If the section
615  /// specifier is invalid, the backend should return a non-empty string
616  /// that indicates the problem.
617  ///
618  /// This hook is a simple quality of implementation feature to catch errors
619  /// and give good diagnostics in cases when the assembler or code generator
620  /// would otherwise reject the section specifier.
621  ///
622  virtual std::string isValidSectionSpecifier(StringRef SR) const {
623    return "";
624  }
625
626  /// \brief Set forced language options.
627  ///
628  /// Apply changes to the target information with respect to certain
629  /// language options which change the target configuration.
630  virtual void adjust(const LangOptions &Opts);
631
632  /// \brief Get the default set of target features for the CPU;
633  /// this should include all legal feature strings on the target.
634  virtual void getDefaultFeatures(llvm::StringMap<bool> &Features) const {
635  }
636
637  /// \brief Get the ABI currently in use.
638  virtual StringRef getABI() const { return StringRef(); }
639
640  /// \brief Get the C++ ABI currently in use.
641  TargetCXXABI getCXXABI() const {
642    return TheCXXABI;
643  }
644
645  /// \brief Target the specified CPU.
646  ///
647  /// \return  False on error (invalid CPU name).
648  virtual bool setCPU(const std::string &Name) {
649    return false;
650  }
651
652  /// \brief Use the specified ABI.
653  ///
654  /// \return False on error (invalid ABI name).
655  virtual bool setABI(const std::string &Name) {
656    return false;
657  }
658
659  /// \brief Use the specified unit for FP math.
660  ///
661  /// \return False on error (invalid unit name).
662  virtual bool setFPMath(StringRef Name) {
663    return false;
664  }
665
666  /// \brief Use this specified C++ ABI.
667  ///
668  /// \return False on error (invalid C++ ABI name).
669  bool setCXXABI(llvm::StringRef name) {
670    TargetCXXABI ABI;
671    if (!ABI.tryParse(name)) return false;
672    return setCXXABI(ABI);
673  }
674
675  /// \brief Set the C++ ABI to be used by this implementation.
676  ///
677  /// \return False on error (ABI not valid on this target)
678  virtual bool setCXXABI(TargetCXXABI ABI) {
679    TheCXXABI = ABI;
680    return true;
681  }
682
683  /// \brief Enable or disable a specific target feature;
684  /// the feature name must be valid.
685  virtual void setFeatureEnabled(llvm::StringMap<bool> &Features,
686                                 StringRef Name,
687                                 bool Enabled) const {
688    Features[Name] = Enabled;
689  }
690
691  /// \brief Perform initialization based on the user configured
692  /// set of features (e.g., +sse4).
693  ///
694  /// The list is guaranteed to have at most one entry per feature.
695  ///
696  /// The target may modify the features list, to change which options are
697  /// passed onwards to the backend.
698  ///
699  /// \return  False on error.
700  virtual bool handleTargetFeatures(std::vector<std::string> &Features,
701                                    DiagnosticsEngine &Diags) {
702    return true;
703  }
704
705  /// \brief Determine whether the given target has the given feature.
706  virtual bool hasFeature(StringRef Feature) const {
707    return false;
708  }
709
710  // \brief Returns maximal number of args passed in registers.
711  unsigned getRegParmMax() const {
712    assert(RegParmMax < 7 && "RegParmMax value is larger than AST can handle");
713    return RegParmMax;
714  }
715
716  /// \brief Whether the target supports thread-local storage.
717  bool isTLSSupported() const {
718    return TLSSupported;
719  }
720
721  /// \brief Return true if {|} are normal characters in the asm string.
722  ///
723  /// If this returns false (the default), then {abc|xyz} is syntax
724  /// that says that when compiling for asm variant #0, "abc" should be
725  /// generated, but when compiling for asm variant #1, "xyz" should be
726  /// generated.
727  bool hasNoAsmVariants() const {
728    return NoAsmVariants;
729  }
730
731  /// \brief Return the register number that __builtin_eh_return_regno would
732  /// return with the specified argument.
733  virtual int getEHDataRegisterNumber(unsigned RegNo) const {
734    return -1;
735  }
736
737  /// \brief Return the section to use for C++ static initialization functions.
738  virtual const char *getStaticInitSectionSpecifier() const {
739    return nullptr;
740  }
741
742  const LangAS::Map &getAddressSpaceMap() const {
743    return *AddrSpaceMap;
744  }
745
746  /// \brief Retrieve the name of the platform as it is used in the
747  /// availability attribute.
748  StringRef getPlatformName() const { return PlatformName; }
749
750  /// \brief Retrieve the minimum desired version of the platform, to
751  /// which the program should be compiled.
752  VersionTuple getPlatformMinVersion() const { return PlatformMinVersion; }
753
754  bool isBigEndian() const { return BigEndian; }
755
756  enum CallingConvMethodType {
757    CCMT_Unknown,
758    CCMT_Member,
759    CCMT_NonMember
760  };
761
762  /// \brief Gets the default calling convention for the given target and
763  /// declaration context.
764  virtual CallingConv getDefaultCallingConv(CallingConvMethodType MT) const {
765    // Not all targets will specify an explicit calling convention that we can
766    // express.  This will always do the right thing, even though it's not
767    // an explicit calling convention.
768    return CC_C;
769  }
770
771  enum CallingConvCheckResult {
772    CCCR_OK,
773    CCCR_Warning
774  };
775
776  /// \brief Determines whether a given calling convention is valid for the
777  /// target. A calling convention can either be accepted, produce a warning
778  /// and be substituted with the default calling convention, or (someday)
779  /// produce an error (such as using thiscall on a non-instance function).
780  virtual CallingConvCheckResult checkCallingConvention(CallingConv CC) const {
781    switch (CC) {
782      default:
783        return CCCR_Warning;
784      case CC_C:
785        return CCCR_OK;
786    }
787  }
788
789protected:
790  virtual uint64_t getPointerWidthV(unsigned AddrSpace) const {
791    return PointerWidth;
792  }
793  virtual uint64_t getPointerAlignV(unsigned AddrSpace) const {
794    return PointerAlign;
795  }
796  virtual enum IntType getPtrDiffTypeV(unsigned AddrSpace) const {
797    return PtrDiffType;
798  }
799  virtual void getGCCRegNames(const char * const *&Names,
800                              unsigned &NumNames) const = 0;
801  virtual void getGCCRegAliases(const GCCRegAlias *&Aliases,
802                                unsigned &NumAliases) const = 0;
803  virtual void getGCCAddlRegNames(const AddlRegName *&Addl,
804                                  unsigned &NumAddl) const {
805    Addl = nullptr;
806    NumAddl = 0;
807  }
808  virtual bool validateAsmConstraint(const char *&Name,
809                                     TargetInfo::ConstraintInfo &info) const= 0;
810};
811
812}  // end namespace clang
813
814#endif
815