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