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thirdparty/clang/include/llvm/IR/Attributes.h

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+//===-- llvm/Attributes.h - Container for Attributes ------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// \brief This file contains the simple types necessary to represent the
+/// attributes associated with functions and their calls.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_IR_ATTRIBUTES_H
+#define LLVM_IR_ATTRIBUTES_H
+
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/FoldingSet.h"
+#include "llvm/Support/PointerLikeTypeTraits.h"
+#include <bitset>
+#include <cassert>
+#include <map>
+#include <string>
+
+namespace llvm {
+
+class AttrBuilder;
+class AttributeImpl;
+class AttributeSetImpl;
+class AttributeSetNode;
+class Constant;
+template<typename T> struct DenseMapInfo;
+class LLVMContext;
+class Type;
+
+//===----------------------------------------------------------------------===//
+/// \class
+/// \brief Functions, function parameters, and return types can have attributes
+/// to indicate how they should be treated by optimizations and code
+/// generation. This class represents one of those attributes. It's light-weight
+/// and should be passed around by-value.
+class Attribute {
+public:
+  /// This enumeration lists the attributes that can be associated with
+  /// parameters, function results, or the function itself.
+  ///
+  /// Note: The `uwtable' attribute is about the ABI or the user mandating an
+  /// entry in the unwind table. The `nounwind' attribute is about an exception
+  /// passing by the function.
+  ///
+  /// In a theoretical system that uses tables for profiling and SjLj for
+  /// exceptions, they would be fully independent. In a normal system that uses
+  /// tables for both, the semantics are:
+  ///
+  /// nil                = Needs an entry because an exception might pass by.
+  /// nounwind           = No need for an entry
+  /// uwtable            = Needs an entry because the ABI says so and because
+  ///                      an exception might pass by.
+  /// uwtable + nounwind = Needs an entry because the ABI says so.
+
+  enum AttrKind {
+    // IR-Level Attributes
+    None,                  ///< No attributes have been set
+    Alignment,             ///< Alignment of parameter (5 bits)
+                           ///< stored as log2 of alignment with +1 bias
+                           ///< 0 means unaligned (different from align(1))
+    AlwaysInline,          ///< inline=always
+    ByVal,                 ///< Pass structure by value
+    InlineHint,            ///< Source said inlining was desirable
+    InReg,                 ///< Force argument to be passed in register
+    MinSize,               ///< Function must be optimized for size first
+    Naked,                 ///< Naked function
+    Nest,                  ///< Nested function static chain
+    NoAlias,               ///< Considered to not alias after call
+    NoBuiltin,             ///< Callee isn't recognized as a builtin
+    NoCapture,             ///< Function creates no aliases of pointer
+    NoDuplicate,           ///< Call cannot be duplicated
+    NoImplicitFloat,       ///< Disable implicit floating point insts
+    NoInline,              ///< inline=never
+    NonLazyBind,           ///< Function is called early and/or
+                           ///< often, so lazy binding isn't worthwhile
+    NoRedZone,             ///< Disable redzone
+    NoReturn,              ///< Mark the function as not returning
+    NoUnwind,              ///< Function doesn't unwind stack
+    OptimizeForSize,       ///< opt_size
+    ReadNone,              ///< Function does not access memory
+    ReadOnly,              ///< Function only reads from memory
+    Returned,              ///< Return value is always equal to this argument
+    ReturnsTwice,          ///< Function can return twice
+    SExt,                  ///< Sign extended before/after call
+    StackAlignment,        ///< Alignment of stack for function (3 bits)
+                           ///< stored as log2 of alignment with +1 bias 0
+                           ///< means unaligned (different from
+                           ///< alignstack=(1))
+    StackProtect,          ///< Stack protection.
+    StackProtectReq,       ///< Stack protection required.
+    StackProtectStrong,    ///< Strong Stack protection.
+    StructRet,             ///< Hidden pointer to structure to return
+    SanitizeAddress,       ///< AddressSanitizer is on.
+    SanitizeThread,        ///< ThreadSanitizer is on.
+    SanitizeMemory,        ///< MemorySanitizer is on.
+    UWTable,               ///< Function must be in a unwind table
+    ZExt,                  ///< Zero extended before/after call
+
+    EndAttrKinds           ///< Sentinal value useful for loops
+  };
+private:
+  AttributeImpl *pImpl;
+  Attribute(AttributeImpl *A) : pImpl(A) {}
+public:
+  Attribute() : pImpl(0) {}
+
+  //===--------------------------------------------------------------------===//
+  // Attribute Construction
+  //===--------------------------------------------------------------------===//
+
+  /// \brief Return a uniquified Attribute object.
+  static Attribute get(LLVMContext &Context, AttrKind Kind, uint64_t Val = 0);
+  static Attribute get(LLVMContext &Context, StringRef Kind,
+                       StringRef Val = StringRef());
+
+  /// \brief Return a uniquified Attribute object that has the specific
+  /// alignment set.
+  static Attribute getWithAlignment(LLVMContext &Context, uint64_t Align);
+  static Attribute getWithStackAlignment(LLVMContext &Context, uint64_t Align);
+
+  //===--------------------------------------------------------------------===//
+  // Attribute Accessors
+  //===--------------------------------------------------------------------===//
+
+  /// \brief Return true if the attribute is an Attribute::AttrKind type.
+  bool isEnumAttribute() const;
+
+  /// \brief Return true if the attribute is an alignment attribute.
+  bool isAlignAttribute() const;
+
+  /// \brief Return true if the attribute is a string (target-dependent)
+  /// attribute.
+  bool isStringAttribute() const;
+
+  /// \brief Return true if the attribute is present.
+  bool hasAttribute(AttrKind Val) const;
+
+  /// \brief Return true if the target-dependent attribute is present.
+  bool hasAttribute(StringRef Val) const;
+
+  /// \brief Return the attribute's kind as an enum (Attribute::AttrKind). This
+  /// requires the attribute to be an enum or alignment attribute.
+  Attribute::AttrKind getKindAsEnum() const;
+
+  /// \brief Return the attribute's value as an integer. This requires that the
+  /// attribute be an alignment attribute.
+  uint64_t getValueAsInt() const;
+
+  /// \brief Return the attribute's kind as a string. This requires the
+  /// attribute to be a string attribute.
+  StringRef getKindAsString() const;
+
+  /// \brief Return the attribute's value as a string. This requires the
+  /// attribute to be a string attribute.
+  StringRef getValueAsString() const;
+
+  /// \brief Returns the alignment field of an attribute as a byte alignment
+  /// value.
+  unsigned getAlignment() const;
+
+  /// \brief Returns the stack alignment field of an attribute as a byte
+  /// alignment value.
+  unsigned getStackAlignment() const;
+
+  /// \brief The Attribute is converted to a string of equivalent mnemonic. This
+  /// is, presumably, for writing out the mnemonics for the assembly writer.
+  std::string getAsString(bool InAttrGrp = false) const;
+
+  /// \brief Equality and non-equality operators.
+  bool operator==(Attribute A) const { return pImpl == A.pImpl; }
+  bool operator!=(Attribute A) const { return pImpl != A.pImpl; }
+
+  /// \brief Less-than operator. Useful for sorting the attributes list.
+  bool operator<(Attribute A) const;
+
+  void Profile(FoldingSetNodeID &ID) const {
+    ID.AddPointer(pImpl);
+  }
+};
+
+//===----------------------------------------------------------------------===//
+/// \class
+/// \brief This class holds the attributes for a function, its return value, and
+/// its parameters. You access the attributes for each of them via an index into
+/// the AttributeSet object. The function attributes are at index
+/// `AttributeSet::FunctionIndex', the return value is at index
+/// `AttributeSet::ReturnIndex', and the attributes for the parameters start at
+/// index `1'.
+class AttributeSet {
+public:
+  enum AttrIndex {
+    ReturnIndex = 0U,
+    FunctionIndex = ~0U
+  };
+private:
+  friend class AttrBuilder;
+  friend class AttributeSetImpl;
+  template <typename Ty> friend struct DenseMapInfo;
+
+  /// \brief The attributes that we are managing. This can be null to represent
+  /// the empty attributes list.
+  AttributeSetImpl *pImpl;
+
+  /// \brief The attributes for the specified index are returned.
+  AttributeSetNode *getAttributes(unsigned Index) const;
+
+  /// \brief Create an AttributeSet with the specified parameters in it.
+  static AttributeSet get(LLVMContext &C,
+                          ArrayRef<std::pair<unsigned, Attribute> > Attrs);
+  static AttributeSet get(LLVMContext &C,
+                          ArrayRef<std::pair<unsigned,
+                                             AttributeSetNode*> > Attrs);
+
+  static AttributeSet getImpl(LLVMContext &C,
+                              ArrayRef<std::pair<unsigned,
+                                                 AttributeSetNode*> > Attrs);
+
+
+  explicit AttributeSet(AttributeSetImpl *LI) : pImpl(LI) {}
+public:
+  AttributeSet() : pImpl(0) {}
+
+  //===--------------------------------------------------------------------===//
+  // AttributeSet Construction and Mutation
+  //===--------------------------------------------------------------------===//
+
+  /// \brief Return an AttributeSet with the specified parameters in it.
+  static AttributeSet get(LLVMContext &C, ArrayRef<AttributeSet> Attrs);
+  static AttributeSet get(LLVMContext &C, unsigned Index,
+                          ArrayRef<Attribute::AttrKind> Kind);
+  static AttributeSet get(LLVMContext &C, unsigned Index, AttrBuilder &B);
+
+  /// \brief Add an attribute to the attribute set at the given index. Since
+  /// attribute sets are immutable, this returns a new set.
+  AttributeSet addAttribute(LLVMContext &C, unsigned Index,
+                            Attribute::AttrKind Attr) const;
+
+  /// \brief Add an attribute to the attribute set at the given index. Since
+  /// attribute sets are immutable, this returns a new set.
+  AttributeSet addAttribute(LLVMContext &C, unsigned Index,
+                            StringRef Kind) const;
+
+  /// \brief Add attributes to the attribute set at the given index. Since
+  /// attribute sets are immutable, this returns a new set.
+  AttributeSet addAttributes(LLVMContext &C, unsigned Index,
+                             AttributeSet Attrs) const;
+
+  /// \brief Remove the specified attribute at the specified index from this
+  /// attribute list. Since attribute lists are immutable, this returns the new
+  /// list.
+  AttributeSet removeAttribute(LLVMContext &C, unsigned Index, 
+                               Attribute::AttrKind Attr) const;
+
+  /// \brief Remove the specified attributes at the specified index from this
+  /// attribute list. Since attribute lists are immutable, this returns the new
+  /// list.
+  AttributeSet removeAttributes(LLVMContext &C, unsigned Index, 
+                                AttributeSet Attrs) const;
+
+  //===--------------------------------------------------------------------===//
+  // AttributeSet Accessors
+  //===--------------------------------------------------------------------===//
+
+  /// \brief Retrieve the LLVM context.
+  LLVMContext &getContext() const;
+
+  /// \brief The attributes for the specified index are returned.
+  AttributeSet getParamAttributes(unsigned Index) const;
+
+  /// \brief The attributes for the ret value are returned.
+  AttributeSet getRetAttributes() const;
+
+  /// \brief The function attributes are returned.
+  AttributeSet getFnAttributes() const;
+
+  /// \brief Return true if the attribute exists at the given index.
+  bool hasAttribute(unsigned Index, Attribute::AttrKind Kind) const;
+
+  /// \brief Return true if the attribute exists at the given index.
+  bool hasAttribute(unsigned Index, StringRef Kind) const;
+
+  /// \brief Return true if attribute exists at the given index.
+  bool hasAttributes(unsigned Index) const;
+
+  /// \brief Return true if the specified attribute is set for at least one
+  /// parameter or for the return value.
+  bool hasAttrSomewhere(Attribute::AttrKind Attr) const;
+
+  /// \brief Return the attribute object that exists at the given index.
+  Attribute getAttribute(unsigned Index, Attribute::AttrKind Kind) const;
+
+  /// \brief Return the attribute object that exists at the given index.
+  Attribute getAttribute(unsigned Index, StringRef Kind) const;
+
+  /// \brief Return the alignment for the specified function parameter.
+  unsigned getParamAlignment(unsigned Index) const;
+
+  /// \brief Get the stack alignment.
+  unsigned getStackAlignment(unsigned Index) const;
+
+  /// \brief Return the attributes at the index as a string.
+  std::string getAsString(unsigned Index, bool TargetIndependent = true,
+                          bool InAttrGrp = false) const;
+
+  typedef ArrayRef<Attribute>::iterator iterator;
+
+  iterator begin(unsigned Slot) const;
+  iterator end(unsigned Slot) const;
+
+  /// operator==/!= - Provide equality predicates.
+  bool operator==(const AttributeSet &RHS) const {
+    return pImpl == RHS.pImpl;
+  }
+  bool operator!=(const AttributeSet &RHS) const {
+    return pImpl != RHS.pImpl;
+  }
+
+  //===--------------------------------------------------------------------===//
+  // AttributeSet Introspection
+  //===--------------------------------------------------------------------===//
+
+  // FIXME: Remove this.
+  uint64_t Raw(unsigned Index) const;
+
+  /// \brief Return a raw pointer that uniquely identifies this attribute list.
+  void *getRawPointer() const {
+    return pImpl;
+  }
+
+  /// \brief Return true if there are no attributes.
+  bool isEmpty() const {
+    return getNumSlots() == 0;
+  }
+
+  /// \brief Return the number of slots used in this attribute list.  This is
+  /// the number of arguments that have an attribute set on them (including the
+  /// function itself).
+  unsigned getNumSlots() const;
+
+  /// \brief Return the index for the given slot.
+  uint64_t getSlotIndex(unsigned Slot) const;
+
+  /// \brief Return the attributes at the given slot.
+  AttributeSet getSlotAttributes(unsigned Slot) const;
+
+  void dump() const;
+};
+
+//===----------------------------------------------------------------------===//
+/// \class
+/// \brief Provide DenseMapInfo for AttributeSet.
+template<> struct DenseMapInfo<AttributeSet> {
+  static inline AttributeSet getEmptyKey() {
+    uintptr_t Val = static_cast<uintptr_t>(-1);
+    Val <<= PointerLikeTypeTraits<void*>::NumLowBitsAvailable;
+    return AttributeSet(reinterpret_cast<AttributeSetImpl*>(Val));
+  }
+  static inline AttributeSet getTombstoneKey() {
+    uintptr_t Val = static_cast<uintptr_t>(-2);
+    Val <<= PointerLikeTypeTraits<void*>::NumLowBitsAvailable;
+    return AttributeSet(reinterpret_cast<AttributeSetImpl*>(Val));
+  }
+  static unsigned getHashValue(AttributeSet AS) {
+    return (unsigned((uintptr_t)AS.pImpl) >> 4) ^
+           (unsigned((uintptr_t)AS.pImpl) >> 9);
+  }
+  static bool isEqual(AttributeSet LHS, AttributeSet RHS) { return LHS == RHS; }
+};
+
+//===----------------------------------------------------------------------===//
+/// \class
+/// \brief This class is used in conjunction with the Attribute::get method to
+/// create an Attribute object. The object itself is uniquified. The Builder's
+/// value, however, is not. So this can be used as a quick way to test for
+/// equality, presence of attributes, etc.
+class AttrBuilder {
+  std::bitset<Attribute::EndAttrKinds> Attrs;
+  std::map<std::string, std::string> TargetDepAttrs;
+  uint64_t Alignment;
+  uint64_t StackAlignment;
+public:
+  AttrBuilder() : Attrs(0), Alignment(0), StackAlignment(0) {}
+  explicit AttrBuilder(uint64_t Val)
+    : Attrs(0), Alignment(0), StackAlignment(0) {
+    addRawValue(Val);
+  }
+  AttrBuilder(const Attribute &A) : Attrs(0), Alignment(0), StackAlignment(0) {
+    addAttribute(A);
+  }
+  AttrBuilder(AttributeSet AS, unsigned Idx);
+  AttrBuilder(const AttrBuilder &B)
+    : Attrs(B.Attrs),
+      TargetDepAttrs(B.TargetDepAttrs.begin(), B.TargetDepAttrs.end()),
+      Alignment(B.Alignment), StackAlignment(B.StackAlignment) {}
+
+  void clear();
+
+  /// \brief Add an attribute to the builder.
+  AttrBuilder &addAttribute(Attribute::AttrKind Val);
+
+  /// \brief Add the Attribute object to the builder.
+  AttrBuilder &addAttribute(Attribute A);
+
+  /// \brief Add the target-dependent attribute to the builder.
+  AttrBuilder &addAttribute(StringRef A, StringRef V = StringRef());
+
+  /// \brief Remove an attribute from the builder.
+  AttrBuilder &removeAttribute(Attribute::AttrKind Val);
+
+  /// \brief Remove the attributes from the builder.
+  AttrBuilder &removeAttributes(AttributeSet A, uint64_t Index);
+
+  /// \brief Remove the target-dependent attribute to the builder.
+  AttrBuilder &removeAttribute(StringRef A);
+
+  /// \brief Add the attributes from the builder.
+  AttrBuilder &merge(const AttrBuilder &B);
+
+  /// \brief Return true if the builder has the specified attribute.
+  bool contains(Attribute::AttrKind A) const {
+    assert((unsigned)A < Attribute::EndAttrKinds && "Attribute out of range!");
+    return Attrs[A];
+  }
+
+  /// \brief Return true if the builder has the specified target-dependent
+  /// attribute.
+  bool contains(StringRef A) const;
+
+  /// \brief Return true if the builder has IR-level attributes.
+  bool hasAttributes() const;
+
+  /// \brief Return true if the builder has any attribute that's in the
+  /// specified attribute.
+  bool hasAttributes(AttributeSet A, uint64_t Index) const;
+
+  /// \brief Return true if the builder has an alignment attribute.
+  bool hasAlignmentAttr() const;
+
+  /// \brief Retrieve the alignment attribute, if it exists.
+  uint64_t getAlignment() const { return Alignment; }
+
+  /// \brief Retrieve the stack alignment attribute, if it exists.
+  uint64_t getStackAlignment() const { return StackAlignment; }
+
+  /// \brief This turns an int alignment (which must be a power of 2) into the
+  /// form used internally in Attribute.
+  AttrBuilder &addAlignmentAttr(unsigned Align);
+
+  /// \brief This turns an int stack alignment (which must be a power of 2) into
+  /// the form used internally in Attribute.
+  AttrBuilder &addStackAlignmentAttr(unsigned Align);
+
+  /// \brief Return true if the builder contains no target-independent
+  /// attributes.
+  bool empty() const { return Attrs.none(); }
+
+  // Iterators for target-dependent attributes.
+  typedef std::pair<std::string, std::string>                td_type;
+  typedef std::map<std::string, std::string>::iterator       td_iterator;
+  typedef std::map<std::string, std::string>::const_iterator td_const_iterator;
+
+  td_iterator td_begin()             { return TargetDepAttrs.begin(); }
+  td_iterator td_end()               { return TargetDepAttrs.end(); }
+
+  td_const_iterator td_begin() const { return TargetDepAttrs.begin(); }
+  td_const_iterator td_end() const   { return TargetDepAttrs.end(); }
+
+  bool td_empty() const              { return TargetDepAttrs.empty(); }
+
+  bool operator==(const AttrBuilder &B);
+  bool operator!=(const AttrBuilder &B) {
+    return !(*this == B);
+  }
+
+  // FIXME: Remove this in 4.0.
+
+  /// \brief Add the raw value to the internal representation.
+  AttrBuilder &addRawValue(uint64_t Val);
+};
+
+namespace AttributeFuncs {
+
+/// \brief Which attributes cannot be applied to a type.
+AttributeSet typeIncompatible(Type *Ty, uint64_t Index);
+
+} // end AttributeFuncs namespace
+
+} // end llvm namespace
+
+#endif