-//===-- llvm/ParameterAttributes.h - Container for Param Attrs --*- C++ -*-===//
+//===-- llvm/ParameterAttributes.h - Container for ParamAttrs ---*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
#ifndef LLVM_PARAMETER_ATTRIBUTES_H
#define LLVM_PARAMETER_ATTRIBUTES_H
-#include <llvm/ADT/SmallVector.h>
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/FoldingSet.h"
namespace llvm {
+namespace ParamAttr {
-/// Function parameters 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.
+/// 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 ParameterAttributes {
- NoAttributeSet = 0, ///< No attributes have been set
- ZExtAttribute = 1 << 0, ///< zero extended before/after call
- SExtAttribute = 1 << 1, ///< sign extended before/after call
- NoReturnAttribute = 1 << 2, ///< mark the function as not returning
- InRegAttribute = 1 << 3, ///< force argument to be passed in register
- StructRetAttribute = 1 << 4, ///< hidden pointer to structure to return
- NoUnwindAttribute = 1 << 5 ///< Function doesn't unwind stack
+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
+ Pure = 1 << 9, ///< Function is pure
+ Const = 1 << 10 ///< Function is const
};
-/// This class is used by Function and CallInst to represent the set of
-/// parameter attributes used. It represents a list of pairs of uint16_t, one
-/// for the parameter index, and one a set of ParameterAttributes bits.
-/// Parameters that have no attributes are not present in the list. The list
-/// may also be empty, but this doesn't occur in practice. The list constructs
-/// as empty and is filled by the insert method. The list can be turned into
-/// a string of mnemonics suitable for LLVM Assembly output. Various accessors
-/// are provided to obtain information about the attributes.
+}
+
+/// 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 {
- /// @name Accessors
+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:
- /// 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 the parameter. The result
- /// is the index of the parameter.
- /// @brief Get a parameter index
- uint16_t getParamIndex(unsigned attr_index) const {
- return attrs[attr_index].index;
- }
+ /// 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
return getParamAttrs(i) & attr;
}
- /// 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.
- /// @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(); }
-
- /// @returns true if this ParamAttrsList is empty.
- /// @brief Determine emptiness of ParamAttrsList.
- unsigned empty() const { return attrs.empty(); }
-
/// 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.
}
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 Mutators
+ /// @name Implementation Details
/// @{
public:
- /// This adds a pair to the list of parameter index and attribute pairs
- /// represented by this class. No check is made to determine whether
- /// param_index exists already. This pair is just added to the end. It is
- /// the user's responsibility to insert the pairs wisely.
- /// @brief Insert ParameterAttributes for an index
- void insert(uint16_t param_index, uint16_t attrs);
+ void Profile(FoldingSetNodeID &ID) const;
+ void dump() const;
/// @}
/// @name Data
/// @{
private:
- /// This is an internal structure used to associate the ParameterAttributes
- /// 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
- };
-
- SmallVector<ParamAttrsWithIndex,2> attrs; ///< The list of attributes
+ ParamAttrsVector attrs; ///< The list of attributes
+ mutable unsigned refCount; ///< The number of references to this object
/// @}
};
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