//===-- llvm/ParameterAttributes.h - Container for ParamAttrs ---*- C++ -*-===// // // The LLVM Compiler Infrastructure // // This file was developed by Reid Spencer and is distributed under the // University of Illinois Open Source License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // This file contains the types necessary to represent the parameter attributes // associated with functions and their calls. // // The implementations of these classes live in lib/VMCore/Function.cpp. // //===----------------------------------------------------------------------===// #ifndef LLVM_PARAMETER_ATTRIBUTES_H #define LLVM_PARAMETER_ATTRIBUTES_H #include "llvm/ADT/SmallVector.h" #include "llvm/ADT/FoldingSet.h" namespace llvm { namespace ParamAttr { /// Function parameters and results can have attributes to indicate how they /// should be treated by optimizations and code generation. This enumeration /// lists the attributes that can be associated with parameters or function /// results. /// @brief Function parameter attributes. enum Attributes { None = 0, ///< No attributes have been set ZExt = 1 << 0, ///< Zero extended before/after call SExt = 1 << 1, ///< Sign extended before/after call NoReturn = 1 << 2, ///< Mark the function as not returning InReg = 1 << 3, ///< Force argument to be passed in register StructRet = 1 << 4, ///< Hidden pointer to structure to return NoUnwind = 1 << 5, ///< Function doesn't unwind stack NoAlias = 1 << 6, ///< Considered to not alias after call ByVal = 1 << 7, ///< Pass structure by value Nest = 1 << 8 ///< Nested function static chain }; } /// This is just a pair of values to associate a set of parameter attributes /// with a parameter index. /// @brief ParameterAttributes with a parameter index. struct ParamAttrsWithIndex { uint16_t attrs; ///< The attributes that are set, |'d together uint16_t index; ///< Index of the parameter for which the attributes apply static ParamAttrsWithIndex get(uint16_t idx, uint16_t attrs) { ParamAttrsWithIndex P; P.index = idx; P.attrs = attrs; return P; } }; /// @brief A vector of attribute/index pairs. typedef SmallVector<ParamAttrsWithIndex,4> ParamAttrsVector; /// @brief A more friendly way to reference the attributes. typedef ParamAttr::Attributes ParameterAttributes; /// This class represents a list of attribute/index pairs for parameter /// attributes. Each entry in the list contains the index of a function /// parameter and the associated ParameterAttributes. If a parameter's index is /// not present in the list, then no attributes are set for that parameter. The /// list may also be empty, but this does not occur in practice. An item in /// the list with an index of 0 refers to the function as a whole or its result. /// To construct a ParamAttrsList, you must first fill a ParamAttrsVector with /// the attribute/index pairs you wish to set. The list of attributes can be /// turned into a string of mnemonics suitable for LLVM Assembly output. /// Various accessors are provided to obtain information about the attributes. /// Note that objects of this class are "uniqued". The \p get method can return /// the pointer of an existing and identical instance. Consequently, reference /// counting is necessary in order to determine when the last reference to a /// ParamAttrsList of a given shape is dropped. Users of this class should use /// the addRef and dropRef methods to add/drop references. When the reference /// count goes to zero, the ParamAttrsList object is deleted. /// This class is used by Function, CallInst and InvokeInst to represent their /// sets of parameter attributes. /// @brief A List of ParameterAttributes. class ParamAttrsList : public FoldingSetNode { /// @name Construction /// @{ private: // ParamAttrsList is uniqued, these should not be publicly available void operator=(const ParamAttrsList &); // Do not implement ParamAttrsList(const ParamAttrsList &); // Do not implement ParamAttrsList(); // Do not implement ~ParamAttrsList(); // Private implementation /// Only the \p get method can invoke this when it wants to create a /// new instance. /// @brief Construct an ParamAttrsList from a ParamAttrsVector explicit ParamAttrsList(const ParamAttrsVector &attrVec) : attrs(attrVec), refCount(0) {} public: /// This method ensures the uniqueness of ParamAttrsList instances. The /// argument is a vector of attribute/index pairs as represented by the /// ParamAttrsWithIndex structure. The vector is used in the construction of /// the ParamAttrsList instance. If an instance with identical vector pairs /// exists, it will be returned instead of creating a new instance. /// @brief Get a ParamAttrsList instance. static ParamAttrsList *get(const ParamAttrsVector &attrVec); /// @} /// @name Accessors /// @{ public: /// The parameter attributes for the \p indexth parameter are returned. /// The 0th parameter refers to the return type of the function. Note that /// the \p param_index is an index into the function's parameters, not an /// index into this class's list of attributes. The result of getParamIndex /// is always suitable input to this function. /// @returns The all the ParameterAttributes for the \p indexth parameter /// as a uint16_t of enumeration values OR'd together. /// @brief Get the attributes for a parameter uint16_t getParamAttrs(uint16_t param_index) const; /// This checks to see if the \p ith function parameter has the parameter /// attribute given by \p attr set. /// @returns true if the parameter attribute is set /// @brief Determine if a ParameterAttributes is set bool paramHasAttr(uint16_t i, ParameterAttributes attr) const { return getParamAttrs(i) & attr; } /// The set of ParameterAttributes set in Attributes is converted to a /// string of equivalent mnemonics. This is, presumably, for writing out /// the mnemonics for the assembly writer. /// @brief Convert parameter attribute bits to text static std::string getParamAttrsText(uint16_t Attributes); /// The \p Indexth parameter attribute is converted to string. /// @brief Get the text for the parmeter attributes for one parameter. std::string getParamAttrsTextByIndex(uint16_t Index) const { return getParamAttrsText(getParamAttrs(Index)); } /// @brief Comparison operator for ParamAttrsList bool operator < (const ParamAttrsList& that) const { if (this->attrs.size() < that.attrs.size()) return true; if (this->attrs.size() > that.attrs.size()) return false; for (unsigned i = 0; i < attrs.size(); ++i) { if (attrs[i].index < that.attrs[i].index) return true; if (attrs[i].index > that.attrs[i].index) return false; if (attrs[i].attrs < that.attrs[i].attrs) return true; if (attrs[i].attrs > that.attrs[i].attrs) return false; } return false; } /// Returns the parameter index of a particular parameter attribute in this /// list of attributes. Note that the attr_index is an index into this /// class's list of attributes, not the index of a parameter. The result /// is the index of the parameter. Clients generally should not use this /// method. It is used internally by LLVM. /// @brief Get a parameter index uint16_t getParamIndex(unsigned attr_index) const { return attrs[attr_index].index; } uint16_t getParamAttrsAtIndex(unsigned attr_index) const { return attrs[attr_index].attrs; } /// Determines how many parameter attributes are set in this ParamAttrsList. /// This says nothing about how many parameters the function has. It also /// says nothing about the highest parameter index that has attributes. /// Clients generally should not use this method. It is used internally by /// LLVM. /// @returns the number of parameter attributes in this ParamAttrsList. /// @brief Return the number of parameter attributes this type has. unsigned size() const { return attrs.size(); } /// Classes retaining references to ParamAttrsList objects should call this /// method to increment the reference count. This ensures that the /// ParamAttrsList object will not disappear until the class drops it. /// @brief Add a reference to this instance. void addRef() const { refCount++; } /// Classes retaining references to ParamAttrsList objects should call this /// method to decrement the reference count and possibly delete the /// ParamAttrsList object. This ensures that ParamAttrsList objects are /// cleaned up only when the last reference to them is dropped. /// @brief Drop a reference to this instance. void dropRef() const { assert(refCount != 0 && "dropRef without addRef"); if (--refCount == 0) delete this; } /// @} /// @name Implementation Details /// @{ public: void Profile(FoldingSetNodeID &ID) const; void dump() const; /// @} /// @name Data /// @{ private: ParamAttrsVector attrs; ///< The list of attributes mutable unsigned refCount; ///< The number of references to this object /// @} }; } // End llvm namespace #endif