| //===-- 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 |