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//===-- 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
};
}
/// 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
};
/// @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;
}
/// 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
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