LLVM API Documentation
00001 //===-- llvm/Attributes.h - Container for Attributes ------------*- C++ -*-===// 00002 // 00003 // The LLVM Compiler Infrastructure 00004 // 00005 // This file is distributed under the University of Illinois Open Source 00006 // License. See LICENSE.TXT for details. 00007 // 00008 //===----------------------------------------------------------------------===// 00009 /// 00010 /// \file 00011 /// \brief This file contains the simple types necessary to represent the 00012 /// attributes associated with functions and their calls. 00013 /// 00014 //===----------------------------------------------------------------------===// 00015 00016 #ifndef LLVM_IR_ATTRIBUTES_H 00017 #define LLVM_IR_ATTRIBUTES_H 00018 00019 #include "llvm/ADT/ArrayRef.h" 00020 #include "llvm/ADT/FoldingSet.h" 00021 #include "llvm/Support/PointerLikeTypeTraits.h" 00022 #include <bitset> 00023 #include <cassert> 00024 #include <map> 00025 #include <string> 00026 00027 namespace llvm { 00028 00029 class AttrBuilder; 00030 class AttributeImpl; 00031 class AttributeSetImpl; 00032 class AttributeSetNode; 00033 class Constant; 00034 template<typename T> struct DenseMapInfo; 00035 class LLVMContext; 00036 class Type; 00037 00038 //===----------------------------------------------------------------------===// 00039 /// \class 00040 /// \brief Functions, function parameters, and return types can have attributes 00041 /// to indicate how they should be treated by optimizations and code 00042 /// generation. This class represents one of those attributes. It's light-weight 00043 /// and should be passed around by-value. 00044 class Attribute { 00045 public: 00046 /// This enumeration lists the attributes that can be associated with 00047 /// parameters, function results, or the function itself. 00048 /// 00049 /// Note: The `uwtable' attribute is about the ABI or the user mandating an 00050 /// entry in the unwind table. The `nounwind' attribute is about an exception 00051 /// passing by the function. 00052 /// 00053 /// In a theoretical system that uses tables for profiling and SjLj for 00054 /// exceptions, they would be fully independent. In a normal system that uses 00055 /// tables for both, the semantics are: 00056 /// 00057 /// nil = Needs an entry because an exception might pass by. 00058 /// nounwind = No need for an entry 00059 /// uwtable = Needs an entry because the ABI says so and because 00060 /// an exception might pass by. 00061 /// uwtable + nounwind = Needs an entry because the ABI says so. 00062 00063 enum AttrKind { 00064 // IR-Level Attributes 00065 None, ///< No attributes have been set 00066 Alignment, ///< Alignment of parameter (5 bits) 00067 ///< stored as log2 of alignment with +1 bias 00068 ///< 0 means unaligned (different from align(1)) 00069 AlwaysInline, ///< inline=always 00070 ByVal, ///< Pass structure by value 00071 InlineHint, ///< Source said inlining was desirable 00072 InReg, ///< Force argument to be passed in register 00073 MinSize, ///< Function must be optimized for size first 00074 Naked, ///< Naked function 00075 Nest, ///< Nested function static chain 00076 NoAlias, ///< Considered to not alias after call 00077 NoBuiltin, ///< Callee isn't recognized as a builtin 00078 NoCapture, ///< Function creates no aliases of pointer 00079 NoDuplicate, ///< Call cannot be duplicated 00080 NoImplicitFloat, ///< Disable implicit floating point insts 00081 NoInline, ///< inline=never 00082 NonLazyBind, ///< Function is called early and/or 00083 ///< often, so lazy binding isn't worthwhile 00084 NoRedZone, ///< Disable redzone 00085 NoReturn, ///< Mark the function as not returning 00086 NoUnwind, ///< Function doesn't unwind stack 00087 OptimizeForSize, ///< opt_size 00088 ReadNone, ///< Function does not access memory 00089 ReadOnly, ///< Function only reads from memory 00090 Returned, ///< Return value is always equal to this argument 00091 ReturnsTwice, ///< Function can return twice 00092 SExt, ///< Sign extended before/after call 00093 StackAlignment, ///< Alignment of stack for function (3 bits) 00094 ///< stored as log2 of alignment with +1 bias 0 00095 ///< means unaligned (different from 00096 ///< alignstack=(1)) 00097 StackProtect, ///< Stack protection. 00098 StackProtectReq, ///< Stack protection required. 00099 StackProtectStrong, ///< Strong Stack protection. 00100 StructRet, ///< Hidden pointer to structure to return 00101 SanitizeAddress, ///< AddressSanitizer is on. 00102 SanitizeThread, ///< ThreadSanitizer is on. 00103 SanitizeMemory, ///< MemorySanitizer is on. 00104 UWTable, ///< Function must be in a unwind table 00105 ZExt, ///< Zero extended before/after call 00106 00107 EndAttrKinds ///< Sentinal value useful for loops 00108 }; 00109 private: 00110 AttributeImpl *pImpl; 00111 Attribute(AttributeImpl *A) : pImpl(A) {} 00112 public: 00113 Attribute() : pImpl(0) {} 00114 00115 //===--------------------------------------------------------------------===// 00116 // Attribute Construction 00117 //===--------------------------------------------------------------------===// 00118 00119 /// \brief Return a uniquified Attribute object. 00120 static Attribute get(LLVMContext &Context, AttrKind Kind, uint64_t Val = 0); 00121 static Attribute get(LLVMContext &Context, StringRef Kind, 00122 StringRef Val = StringRef()); 00123 00124 /// \brief Return a uniquified Attribute object that has the specific 00125 /// alignment set. 00126 static Attribute getWithAlignment(LLVMContext &Context, uint64_t Align); 00127 static Attribute getWithStackAlignment(LLVMContext &Context, uint64_t Align); 00128 00129 //===--------------------------------------------------------------------===// 00130 // Attribute Accessors 00131 //===--------------------------------------------------------------------===// 00132 00133 /// \brief Return true if the attribute is an Attribute::AttrKind type. 00134 bool isEnumAttribute() const; 00135 00136 /// \brief Return true if the attribute is an alignment attribute. 00137 bool isAlignAttribute() const; 00138 00139 /// \brief Return true if the attribute is a string (target-dependent) 00140 /// attribute. 00141 bool isStringAttribute() const; 00142 00143 /// \brief Return true if the attribute is present. 00144 bool hasAttribute(AttrKind Val) const; 00145 00146 /// \brief Return true if the target-dependent attribute is present. 00147 bool hasAttribute(StringRef Val) const; 00148 00149 /// \brief Return the attribute's kind as an enum (Attribute::AttrKind). This 00150 /// requires the attribute to be an enum or alignment attribute. 00151 Attribute::AttrKind getKindAsEnum() const; 00152 00153 /// \brief Return the attribute's value as an integer. This requires that the 00154 /// attribute be an alignment attribute. 00155 uint64_t getValueAsInt() const; 00156 00157 /// \brief Return the attribute's kind as a string. This requires the 00158 /// attribute to be a string attribute. 00159 StringRef getKindAsString() const; 00160 00161 /// \brief Return the attribute's value as a string. This requires the 00162 /// attribute to be a string attribute. 00163 StringRef getValueAsString() const; 00164 00165 /// \brief Returns the alignment field of an attribute as a byte alignment 00166 /// value. 00167 unsigned getAlignment() const; 00168 00169 /// \brief Returns the stack alignment field of an attribute as a byte 00170 /// alignment value. 00171 unsigned getStackAlignment() const; 00172 00173 /// \brief The Attribute is converted to a string of equivalent mnemonic. This 00174 /// is, presumably, for writing out the mnemonics for the assembly writer. 00175 std::string getAsString(bool InAttrGrp = false) const; 00176 00177 /// \brief Equality and non-equality operators. 00178 bool operator==(Attribute A) const { return pImpl == A.pImpl; } 00179 bool operator!=(Attribute A) const { return pImpl != A.pImpl; } 00180 00181 /// \brief Less-than operator. Useful for sorting the attributes list. 00182 bool operator<(Attribute A) const; 00183 00184 void Profile(FoldingSetNodeID &ID) const { 00185 ID.AddPointer(pImpl); 00186 } 00187 }; 00188 00189 //===----------------------------------------------------------------------===// 00190 /// \class 00191 /// \brief This class holds the attributes for a function, its return value, and 00192 /// its parameters. You access the attributes for each of them via an index into 00193 /// the AttributeSet object. The function attributes are at index 00194 /// `AttributeSet::FunctionIndex', the return value is at index 00195 /// `AttributeSet::ReturnIndex', and the attributes for the parameters start at 00196 /// index `1'. 00197 class AttributeSet { 00198 public: 00199 enum AttrIndex { 00200 ReturnIndex = 0U, 00201 FunctionIndex = ~0U 00202 }; 00203 private: 00204 friend class AttrBuilder; 00205 friend class AttributeSetImpl; 00206 template <typename Ty> friend struct DenseMapInfo; 00207 00208 /// \brief The attributes that we are managing. This can be null to represent 00209 /// the empty attributes list. 00210 AttributeSetImpl *pImpl; 00211 00212 /// \brief The attributes for the specified index are returned. 00213 AttributeSetNode *getAttributes(unsigned Index) const; 00214 00215 /// \brief Create an AttributeSet with the specified parameters in it. 00216 static AttributeSet get(LLVMContext &C, 00217 ArrayRef<std::pair<unsigned, Attribute> > Attrs); 00218 static AttributeSet get(LLVMContext &C, 00219 ArrayRef<std::pair<unsigned, 00220 AttributeSetNode*> > Attrs); 00221 00222 static AttributeSet getImpl(LLVMContext &C, 00223 ArrayRef<std::pair<unsigned, 00224 AttributeSetNode*> > Attrs); 00225 00226 00227 explicit AttributeSet(AttributeSetImpl *LI) : pImpl(LI) {} 00228 public: 00229 AttributeSet() : pImpl(0) {} 00230 00231 //===--------------------------------------------------------------------===// 00232 // AttributeSet Construction and Mutation 00233 //===--------------------------------------------------------------------===// 00234 00235 /// \brief Return an AttributeSet with the specified parameters in it. 00236 static AttributeSet get(LLVMContext &C, ArrayRef<AttributeSet> Attrs); 00237 static AttributeSet get(LLVMContext &C, unsigned Index, 00238 ArrayRef<Attribute::AttrKind> Kind); 00239 static AttributeSet get(LLVMContext &C, unsigned Index, AttrBuilder &B); 00240 00241 /// \brief Add an attribute to the attribute set at the given index. Since 00242 /// attribute sets are immutable, this returns a new set. 00243 AttributeSet addAttribute(LLVMContext &C, unsigned Index, 00244 Attribute::AttrKind Attr) const; 00245 00246 /// \brief Add an attribute to the attribute set at the given index. Since 00247 /// attribute sets are immutable, this returns a new set. 00248 AttributeSet addAttribute(LLVMContext &C, unsigned Index, 00249 StringRef Kind) const; 00250 00251 /// \brief Add attributes to the attribute set at the given index. Since 00252 /// attribute sets are immutable, this returns a new set. 00253 AttributeSet addAttributes(LLVMContext &C, unsigned Index, 00254 AttributeSet Attrs) const; 00255 00256 /// \brief Remove the specified attribute at the specified index from this 00257 /// attribute list. Since attribute lists are immutable, this returns the new 00258 /// list. 00259 AttributeSet removeAttribute(LLVMContext &C, unsigned Index, 00260 Attribute::AttrKind Attr) const; 00261 00262 /// \brief Remove the specified attributes at the specified index from this 00263 /// attribute list. Since attribute lists are immutable, this returns the new 00264 /// list. 00265 AttributeSet removeAttributes(LLVMContext &C, unsigned Index, 00266 AttributeSet Attrs) const; 00267 00268 //===--------------------------------------------------------------------===// 00269 // AttributeSet Accessors 00270 //===--------------------------------------------------------------------===// 00271 00272 /// \brief Retrieve the LLVM context. 00273 LLVMContext &getContext() const; 00274 00275 /// \brief The attributes for the specified index are returned. 00276 AttributeSet getParamAttributes(unsigned Index) const; 00277 00278 /// \brief The attributes for the ret value are returned. 00279 AttributeSet getRetAttributes() const; 00280 00281 /// \brief The function attributes are returned. 00282 AttributeSet getFnAttributes() const; 00283 00284 /// \brief Return true if the attribute exists at the given index. 00285 bool hasAttribute(unsigned Index, Attribute::AttrKind Kind) const; 00286 00287 /// \brief Return true if the attribute exists at the given index. 00288 bool hasAttribute(unsigned Index, StringRef Kind) const; 00289 00290 /// \brief Return true if attribute exists at the given index. 00291 bool hasAttributes(unsigned Index) const; 00292 00293 /// \brief Return true if the specified attribute is set for at least one 00294 /// parameter or for the return value. 00295 bool hasAttrSomewhere(Attribute::AttrKind Attr) const; 00296 00297 /// \brief Return the attribute object that exists at the given index. 00298 Attribute getAttribute(unsigned Index, Attribute::AttrKind Kind) const; 00299 00300 /// \brief Return the attribute object that exists at the given index. 00301 Attribute getAttribute(unsigned Index, StringRef Kind) const; 00302 00303 /// \brief Return the alignment for the specified function parameter. 00304 unsigned getParamAlignment(unsigned Index) const; 00305 00306 /// \brief Get the stack alignment. 00307 unsigned getStackAlignment(unsigned Index) const; 00308 00309 /// \brief Return the attributes at the index as a string. 00310 std::string getAsString(unsigned Index, bool InAttrGrp = false) const; 00311 00312 typedef ArrayRef<Attribute>::iterator iterator; 00313 00314 iterator begin(unsigned Slot) const; 00315 iterator end(unsigned Slot) const; 00316 00317 /// operator==/!= - Provide equality predicates. 00318 bool operator==(const AttributeSet &RHS) const { 00319 return pImpl == RHS.pImpl; 00320 } 00321 bool operator!=(const AttributeSet &RHS) const { 00322 return pImpl != RHS.pImpl; 00323 } 00324 00325 //===--------------------------------------------------------------------===// 00326 // AttributeSet Introspection 00327 //===--------------------------------------------------------------------===// 00328 00329 // FIXME: Remove this. 00330 uint64_t Raw(unsigned Index) const; 00331 00332 /// \brief Return a raw pointer that uniquely identifies this attribute list. 00333 void *getRawPointer() const { 00334 return pImpl; 00335 } 00336 00337 /// \brief Return true if there are no attributes. 00338 bool isEmpty() const { 00339 return getNumSlots() == 0; 00340 } 00341 00342 /// \brief Return the number of slots used in this attribute list. This is 00343 /// the number of arguments that have an attribute set on them (including the 00344 /// function itself). 00345 unsigned getNumSlots() const; 00346 00347 /// \brief Return the index for the given slot. 00348 unsigned getSlotIndex(unsigned Slot) const; 00349 00350 /// \brief Return the attributes at the given slot. 00351 AttributeSet getSlotAttributes(unsigned Slot) const; 00352 00353 void dump() const; 00354 }; 00355 00356 //===----------------------------------------------------------------------===// 00357 /// \class 00358 /// \brief Provide DenseMapInfo for AttributeSet. 00359 template<> struct DenseMapInfo<AttributeSet> { 00360 static inline AttributeSet getEmptyKey() { 00361 uintptr_t Val = static_cast<uintptr_t>(-1); 00362 Val <<= PointerLikeTypeTraits<void*>::NumLowBitsAvailable; 00363 return AttributeSet(reinterpret_cast<AttributeSetImpl*>(Val)); 00364 } 00365 static inline AttributeSet getTombstoneKey() { 00366 uintptr_t Val = static_cast<uintptr_t>(-2); 00367 Val <<= PointerLikeTypeTraits<void*>::NumLowBitsAvailable; 00368 return AttributeSet(reinterpret_cast<AttributeSetImpl*>(Val)); 00369 } 00370 static unsigned getHashValue(AttributeSet AS) { 00371 return (unsigned((uintptr_t)AS.pImpl) >> 4) ^ 00372 (unsigned((uintptr_t)AS.pImpl) >> 9); 00373 } 00374 static bool isEqual(AttributeSet LHS, AttributeSet RHS) { return LHS == RHS; } 00375 }; 00376 00377 //===----------------------------------------------------------------------===// 00378 /// \class 00379 /// \brief This class is used in conjunction with the Attribute::get method to 00380 /// create an Attribute object. The object itself is uniquified. The Builder's 00381 /// value, however, is not. So this can be used as a quick way to test for 00382 /// equality, presence of attributes, etc. 00383 class AttrBuilder { 00384 std::bitset<Attribute::EndAttrKinds> Attrs; 00385 std::map<std::string, std::string> TargetDepAttrs; 00386 uint64_t Alignment; 00387 uint64_t StackAlignment; 00388 public: 00389 AttrBuilder() : Attrs(0), Alignment(0), StackAlignment(0) {} 00390 explicit AttrBuilder(uint64_t Val) 00391 : Attrs(0), Alignment(0), StackAlignment(0) { 00392 addRawValue(Val); 00393 } 00394 AttrBuilder(const Attribute &A) : Attrs(0), Alignment(0), StackAlignment(0) { 00395 addAttribute(A); 00396 } 00397 AttrBuilder(AttributeSet AS, unsigned Idx); 00398 AttrBuilder(const AttrBuilder &B) 00399 : Attrs(B.Attrs), 00400 TargetDepAttrs(B.TargetDepAttrs.begin(), B.TargetDepAttrs.end()), 00401 Alignment(B.Alignment), StackAlignment(B.StackAlignment) {} 00402 00403 void clear(); 00404 00405 /// \brief Add an attribute to the builder. 00406 AttrBuilder &addAttribute(Attribute::AttrKind Val); 00407 00408 /// \brief Add the Attribute object to the builder. 00409 AttrBuilder &addAttribute(Attribute A); 00410 00411 /// \brief Add the target-dependent attribute to the builder. 00412 AttrBuilder &addAttribute(StringRef A, StringRef V = StringRef()); 00413 00414 /// \brief Remove an attribute from the builder. 00415 AttrBuilder &removeAttribute(Attribute::AttrKind Val); 00416 00417 /// \brief Remove the attributes from the builder. 00418 AttrBuilder &removeAttributes(AttributeSet A, uint64_t Index); 00419 00420 /// \brief Remove the target-dependent attribute to the builder. 00421 AttrBuilder &removeAttribute(StringRef A); 00422 00423 /// \brief Add the attributes from the builder. 00424 AttrBuilder &merge(const AttrBuilder &B); 00425 00426 /// \brief Return true if the builder has the specified attribute. 00427 bool contains(Attribute::AttrKind A) const { 00428 assert((unsigned)A < Attribute::EndAttrKinds && "Attribute out of range!"); 00429 return Attrs[A]; 00430 } 00431 00432 /// \brief Return true if the builder has the specified target-dependent 00433 /// attribute. 00434 bool contains(StringRef A) const; 00435 00436 /// \brief Return true if the builder has IR-level attributes. 00437 bool hasAttributes() const; 00438 00439 /// \brief Return true if the builder has any attribute that's in the 00440 /// specified attribute. 00441 bool hasAttributes(AttributeSet A, uint64_t Index) const; 00442 00443 /// \brief Return true if the builder has an alignment attribute. 00444 bool hasAlignmentAttr() const; 00445 00446 /// \brief Retrieve the alignment attribute, if it exists. 00447 uint64_t getAlignment() const { return Alignment; } 00448 00449 /// \brief Retrieve the stack alignment attribute, if it exists. 00450 uint64_t getStackAlignment() const { return StackAlignment; } 00451 00452 /// \brief This turns an int alignment (which must be a power of 2) into the 00453 /// form used internally in Attribute. 00454 AttrBuilder &addAlignmentAttr(unsigned Align); 00455 00456 /// \brief This turns an int stack alignment (which must be a power of 2) into 00457 /// the form used internally in Attribute. 00458 AttrBuilder &addStackAlignmentAttr(unsigned Align); 00459 00460 /// \brief Return true if the builder contains no target-independent 00461 /// attributes. 00462 bool empty() const { return Attrs.none(); } 00463 00464 // Iterators for target-dependent attributes. 00465 typedef std::pair<std::string, std::string> td_type; 00466 typedef std::map<std::string, std::string>::iterator td_iterator; 00467 typedef std::map<std::string, std::string>::const_iterator td_const_iterator; 00468 00469 td_iterator td_begin() { return TargetDepAttrs.begin(); } 00470 td_iterator td_end() { return TargetDepAttrs.end(); } 00471 00472 td_const_iterator td_begin() const { return TargetDepAttrs.begin(); } 00473 td_const_iterator td_end() const { return TargetDepAttrs.end(); } 00474 00475 bool td_empty() const { return TargetDepAttrs.empty(); } 00476 00477 bool operator==(const AttrBuilder &B); 00478 bool operator!=(const AttrBuilder &B) { 00479 return !(*this == B); 00480 } 00481 00482 // FIXME: Remove this in 4.0. 00483 00484 /// \brief Add the raw value to the internal representation. 00485 AttrBuilder &addRawValue(uint64_t Val); 00486 }; 00487 00488 namespace AttributeFuncs { 00489 00490 /// \brief Which attributes cannot be applied to a type. 00491 AttributeSet typeIncompatible(Type *Ty, uint64_t Index); 00492 00493 } // end AttributeFuncs namespace 00494 00495 } // end llvm namespace 00496 00497 #endif