llvm-6502/include/llvm/Attributes.h
2012-12-19 22:42:22 +00:00

385 lines
15 KiB
C++

//===-- llvm/Attributes.h - Container for Attributes ------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains the simple types necessary to represent the
// attributes associated with functions and their calls.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ATTRIBUTES_H
#define LLVM_ATTRIBUTES_H
#include "llvm/ADT/ArrayRef.h"
#include "llvm/Support/MathExtras.h"
#include <cassert>
#include <string>
namespace llvm {
class AttrBuilder;
class AttributesImpl;
class LLVMContext;
class Type;
//===----------------------------------------------------------------------===//
/// \class Functions, function parameters, and return types can have attributes
/// to indicate how they should be treated by optimizations and code
/// generation. This class represents one of those attributes. It's light-weight
/// and should be passed around by-value.
class Attribute {
public:
/// This enumeration lists the attributes that can be associated with
/// parameters, function results or the function itself.
///
/// Note: uwtable is about the ABI or the user mandating an entry in the
/// unwind table. The nounwind attribute is about an exception passing by the
/// function.
///
/// In a theoretical system that uses tables for profiling and sjlj for
/// exceptions, they would be fully independent. In a normal system that uses
/// tables for both, the semantics are:
///
/// nil = Needs an entry because an exception might pass by.
/// nounwind = No need for an entry
/// uwtable = Needs an entry because the ABI says so and because
/// an exception might pass by.
/// uwtable + nounwind = Needs an entry because the ABI says so.
enum AttrVal {
// IR-Level Attributes
None, ///< No attributes have been set
AddressSafety, ///< Address safety checking is on.
Alignment, ///< Alignment of parameter (5 bits)
///< stored as log2 of alignment with +1 bias
///< 0 means unaligned different from align 1
AlwaysInline, ///< inline=always
ByVal, ///< Pass structure by value
InlineHint, ///< Source said inlining was desirable
InReg, ///< Force argument to be passed in register
MinSize, ///< Function must be optimized for size first
Naked, ///< Naked function
Nest, ///< Nested function static chain
NoAlias, ///< Considered to not alias after call
NoCapture, ///< Function creates no aliases of pointer
NoImplicitFloat, ///< Disable implicit floating point insts
NoInline, ///< inline=never
NonLazyBind, ///< Function is called early and/or
///< often, so lazy binding isn't worthwhile
NoRedZone, ///< Disable redzone
NoReturn, ///< Mark the function as not returning
NoUnwind, ///< Function doesn't unwind stack
OptimizeForSize, ///< opt_size
ReadNone, ///< Function does not access memory
ReadOnly, ///< Function only reads from memory
ReturnsTwice, ///< Function can return twice
SExt, ///< Sign extended before/after call
StackAlignment, ///< Alignment of stack for function (3 bits)
///< stored as log2 of alignment with +1 bias 0
///< means unaligned (different from
///< alignstack={1))
StackProtect, ///< Stack protection.
StackProtectReq, ///< Stack protection required.
StructRet, ///< Hidden pointer to structure to return
UWTable, ///< Function must be in a unwind table
ZExt ///< Zero extended before/after call
};
private:
AttributesImpl *Attrs;
Attribute(AttributesImpl *A) : Attrs(A) {}
public:
Attribute() : Attrs(0) {}
/// \brief Return a uniquified Attribute object. This takes the uniquified
/// value from the Builder and wraps it in the Attribute class.
static Attribute get(LLVMContext &Context, ArrayRef<AttrVal> Vals);
static Attribute get(LLVMContext &Context, AttrBuilder &B);
/// \brief Return true if the attribute is present.
bool hasAttribute(AttrVal Val) const;
/// \brief Return true if attributes exist
bool hasAttributes() const;
/// \brief Return true if the attributes are a non-null intersection.
bool hasAttributes(const Attribute &A) const;
/// \brief Returns the alignment field of an attribute as a byte alignment
/// value.
unsigned getAlignment() const;
/// \brief Returns the stack alignment field of an attribute as a byte
/// alignment value.
unsigned getStackAlignment() const;
bool operator==(const Attribute &A) const {
return Attrs == A.Attrs;
}
bool operator!=(const Attribute &A) const {
return Attrs != A.Attrs;
}
uint64_t Raw() const;
/// \brief Which attributes cannot be applied to a type.
static Attribute typeIncompatible(Type *Ty);
/// \brief This returns an integer containing an encoding of all the LLVM
/// attributes found in the given attribute bitset. Any change to this
/// encoding is a breaking change to bitcode compatibility.
static uint64_t encodeLLVMAttributesForBitcode(Attribute Attrs);
/// \brief This returns an attribute bitset containing the LLVM attributes
/// that have been decoded from the given integer. This function must stay in
/// sync with 'encodeLLVMAttributesForBitcode'.
static Attribute decodeLLVMAttributesForBitcode(LLVMContext &C,
uint64_t EncodedAttrs);
/// \brief The set of attributes set in Attribute is converted to a string of
/// equivalent mnemonics. This is, presumably, for writing out the mnemonics
/// for the assembly writer.
std::string getAsString() const;
};
//===----------------------------------------------------------------------===//
/// AttrBuilder - This class is used in conjunction with the Attribute::get
/// method to create an Attribute object. The object itself is uniquified. The
/// Builder's value, however, is not. So this can be used as a quick way to test
/// for equality, presence of attributes, etc.
class AttrBuilder {
uint64_t Bits;
public:
AttrBuilder() : Bits(0) {}
explicit AttrBuilder(uint64_t B) : Bits(B) {}
AttrBuilder(const Attribute &A) : Bits(A.Raw()) {}
void clear() { Bits = 0; }
/// addAttribute - Add an attribute to the builder.
AttrBuilder &addAttribute(Attribute::AttrVal Val);
/// removeAttribute - Remove an attribute from the builder.
AttrBuilder &removeAttribute(Attribute::AttrVal Val);
/// addAttribute - Add the attributes from A to the builder.
AttrBuilder &addAttributes(const Attribute &A);
/// removeAttribute - Remove the attributes from A from the builder.
AttrBuilder &removeAttributes(const Attribute &A);
/// hasAttribute - Return true if the builder has the specified attribute.
bool hasAttribute(Attribute::AttrVal A) const;
/// hasAttributes - Return true if the builder has IR-level attributes.
bool hasAttributes() const;
/// hasAttributes - Return true if the builder has any attribute that's in the
/// specified attribute.
bool hasAttributes(const Attribute &A) const;
/// hasAlignmentAttr - Return true if the builder has an alignment attribute.
bool hasAlignmentAttr() const;
/// getAlignment - Retrieve the alignment attribute, if it exists.
uint64_t getAlignment() const;
/// getStackAlignment - Retrieve the stack alignment attribute, if it exists.
uint64_t getStackAlignment() const;
/// addAlignmentAttr - This turns an int alignment (which must be a power of
/// 2) into the form used internally in Attribute.
AttrBuilder &addAlignmentAttr(unsigned Align);
/// addStackAlignmentAttr - This turns an int stack alignment (which must be a
/// power of 2) into the form used internally in Attribute.
AttrBuilder &addStackAlignmentAttr(unsigned Align);
/// addRawValue - Add the raw value to the internal representation.
/// N.B. This should be used ONLY for decoding LLVM bitcode!
AttrBuilder &addRawValue(uint64_t Val);
/// @brief Remove attributes that are used on functions only.
void removeFunctionOnlyAttrs() {
removeAttribute(Attribute::NoReturn)
.removeAttribute(Attribute::NoUnwind)
.removeAttribute(Attribute::ReadNone)
.removeAttribute(Attribute::ReadOnly)
.removeAttribute(Attribute::NoInline)
.removeAttribute(Attribute::AlwaysInline)
.removeAttribute(Attribute::OptimizeForSize)
.removeAttribute(Attribute::StackProtect)
.removeAttribute(Attribute::StackProtectReq)
.removeAttribute(Attribute::NoRedZone)
.removeAttribute(Attribute::NoImplicitFloat)
.removeAttribute(Attribute::Naked)
.removeAttribute(Attribute::InlineHint)
.removeAttribute(Attribute::StackAlignment)
.removeAttribute(Attribute::UWTable)
.removeAttribute(Attribute::NonLazyBind)
.removeAttribute(Attribute::ReturnsTwice)
.removeAttribute(Attribute::AddressSafety)
.removeAttribute(Attribute::MinSize);
}
uint64_t Raw() const { return Bits; }
bool operator==(const AttrBuilder &B) {
return Bits == B.Bits;
}
bool operator!=(const AttrBuilder &B) {
return Bits != B.Bits;
}
};
//===----------------------------------------------------------------------===//
/// \class This is just a pair of values to associate a set of attributes with
/// an index.
struct AttributeWithIndex {
Attribute Attrs; ///< The attributes that are set, or'd together.
unsigned Index; ///< Index of the parameter for which the attributes apply.
///< Index 0 is used for return value attributes.
///< Index ~0U is used for function attributes.
static AttributeWithIndex get(LLVMContext &C, unsigned Idx,
ArrayRef<Attribute::AttrVal> Attrs) {
return get(Idx, Attribute::get(C, Attrs));
}
static AttributeWithIndex get(unsigned Idx, Attribute Attrs) {
AttributeWithIndex P;
P.Index = Idx;
P.Attrs = Attrs;
return P;
}
};
//===----------------------------------------------------------------------===//
// AttributeSet Smart Pointer
//===----------------------------------------------------------------------===//
class AttributeSetImpl;
//===----------------------------------------------------------------------===//
/// \class This class manages the ref count for the opaque AttributeSetImpl
/// object and provides accessors for it.
class AttributeSet {
public:
enum AttrIndex {
ReturnIndex = 0U,
FunctionIndex = ~0U
};
private:
/// \brief The attributes that we are managing. This can be null to represent
/// the empty attributes list.
AttributeSetImpl *AttrList;
/// \brief The attributes for the specified index are returned. Attributes
/// for the result are denoted with Idx = 0.
Attribute getAttributes(unsigned Idx) const;
explicit AttributeSet(AttributeSetImpl *LI) : AttrList(LI) {}
public:
AttributeSet() : AttrList(0) {}
AttributeSet(const AttributeSet &P) : AttrList(P.AttrList) {}
const AttributeSet &operator=(const AttributeSet &RHS);
//===--------------------------------------------------------------------===//
// Attribute List Construction and Mutation
//===--------------------------------------------------------------------===//
/// \brief Return an AttributeSet with the specified parameters in it.
static AttributeSet get(LLVMContext &C, ArrayRef<AttributeWithIndex> Attrs);
/// \brief Add the specified attribute at the specified index to this
/// attribute list. Since attribute lists are immutable, this returns the new
/// list.
AttributeSet addAttr(LLVMContext &C, unsigned Idx, Attribute Attrs) const;
/// \brief Remove the specified attribute at the specified index from this
/// attribute list. Since attribute lists are immutable, this returns the new
/// list.
AttributeSet removeAttr(LLVMContext &C, unsigned Idx, Attribute Attrs) const;
//===--------------------------------------------------------------------===//
// Attribute List Accessors
//===--------------------------------------------------------------------===//
/// \brief The attributes for the specified index are returned.
Attribute getParamAttributes(unsigned Idx) const {
return getAttributes(Idx);
}
/// \brief The attributes for the ret value are returned.
Attribute getRetAttributes() const {
return getAttributes(ReturnIndex);
}
/// \brief The function attributes are returned.
Attribute getFnAttributes() const {
return getAttributes(FunctionIndex);
}
/// \brief Return true if the specified parameter index has the specified
/// attribute set.
bool paramHasAttr(unsigned Idx, Attribute Attr) const {
return getAttributes(Idx).hasAttributes(Attr);
}
/// \brief Return the alignment for the specified function parameter.
unsigned getParamAlignment(unsigned Idx) const {
return getAttributes(Idx).getAlignment();
}
/// \brief Return true if the specified attribute is set for at least one
/// parameter or for the return value.
bool hasAttrSomewhere(Attribute::AttrVal Attr) const;
unsigned getNumAttrs() const;
Attribute &getAttributesAtIndex(unsigned i) const;
/// operator==/!= - Provide equality predicates.
bool operator==(const AttributeSet &RHS) const {
return AttrList == RHS.AttrList;
}
bool operator!=(const AttributeSet &RHS) const {
return AttrList != RHS.AttrList;
}
//===--------------------------------------------------------------------===//
// Attribute List Introspection
//===--------------------------------------------------------------------===//
/// \brief Return a raw pointer that uniquely identifies this attribute list.
void *getRawPointer() const {
return AttrList;
}
// Attributes are stored as a dense set of slots, where there is one slot for
// each argument that has an attribute. This allows walking over the dense
// set instead of walking the sparse list of attributes.
/// \brief Return true if there are no attributes.
bool isEmpty() const {
return AttrList == 0;
}
/// \brief Return the number of slots used in this attribute list. This is
/// the number of arguments that have an attribute set on them (including the
/// function itself).
unsigned getNumSlots() const;
/// \brief Return the AttributeWithIndex at the specified slot. This holds a
/// index number plus a set of attributes.
const AttributeWithIndex &getSlot(unsigned Slot) const;
void dump() const;
};
} // End llvm namespace
#endif