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