llvm-6502/include/llvm/Attributes.h
Meador Inge e99f8be067 PR12696: Attribute bits above 1<<30 are not encoded in bitcode
Attribute bits above 1<<30 are now encoded correctly.  Additionally,
the encoding/decoding functionality has been hoisted to helper functions
in Attributes.h in an effort to help the encoding/decoding to stay in
sync with the Attribute bitcode definitions.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157581 91177308-0d34-0410-b5e6-96231b3b80d8
2012-05-28 15:45:43 +00:00

415 lines
16 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/Support/MathExtras.h"
#include "llvm/ADT/ArrayRef.h"
#include <cassert>
#include <string>
namespace llvm {
class Type;
namespace Attribute {
/// We use this proxy POD type to allow constructing Attributes constants
/// using initializer lists. Do not use this class directly.
struct AttrConst {
uint64_t v;
AttrConst operator | (const AttrConst Attrs) const {
AttrConst Res = {v | Attrs.v};
return Res;
}
AttrConst operator ~ () const {
AttrConst Res = {~v};
return Res;
}
};
} // namespace Attribute
/// Attributes - A bitset of attributes.
class Attributes {
public:
Attributes() : Bits(0) { }
explicit Attributes(uint64_t Val) : Bits(Val) { }
/*implicit*/ Attributes(Attribute::AttrConst Val) : Bits(Val.v) { }
Attributes(const Attributes &Attrs) : Bits(Attrs.Bits) { }
// This is a "safe bool() operator".
operator const void *() const { return Bits ? this : 0; }
bool isEmptyOrSingleton() const { return (Bits & (Bits - 1)) == 0; }
Attributes &operator = (const Attributes &Attrs) {
Bits = Attrs.Bits;
return *this;
}
bool operator == (const Attributes &Attrs) const {
return Bits == Attrs.Bits;
}
bool operator != (const Attributes &Attrs) const {
return Bits != Attrs.Bits;
}
Attributes operator | (const Attributes &Attrs) const {
return Attributes(Bits | Attrs.Bits);
}
Attributes operator & (const Attributes &Attrs) const {
return Attributes(Bits & Attrs.Bits);
}
Attributes operator ^ (const Attributes &Attrs) const {
return Attributes(Bits ^ Attrs.Bits);
}
Attributes &operator |= (const Attributes &Attrs) {
Bits |= Attrs.Bits;
return *this;
}
Attributes &operator &= (const Attributes &Attrs) {
Bits &= Attrs.Bits;
return *this;
}
Attributes operator ~ () const { return Attributes(~Bits); }
uint64_t Raw() const { return Bits; }
private:
// Currently, we need less than 64 bits.
uint64_t Bits;
};
namespace Attribute {
/// 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, function
/// results or the function itself.
/// @brief Function attributes.
// We declare AttrConst objects that will be used throughout the code
// and also raw uint64_t objects with _i suffix to be used below for other
// constant declarations. This is done to avoid static CTORs and at the same
// time to keep type-safety of Attributes.
#define DECLARE_LLVM_ATTRIBUTE(name, value) \
const uint64_t name##_i = value; \
const AttrConst name = {value};
DECLARE_LLVM_ATTRIBUTE(None,0) ///< No attributes have been set
DECLARE_LLVM_ATTRIBUTE(ZExt,1<<0) ///< Zero extended before/after call
DECLARE_LLVM_ATTRIBUTE(SExt,1<<1) ///< Sign extended before/after call
DECLARE_LLVM_ATTRIBUTE(NoReturn,1<<2) ///< Mark the function as not returning
DECLARE_LLVM_ATTRIBUTE(InReg,1<<3) ///< Force argument to be passed in register
DECLARE_LLVM_ATTRIBUTE(StructRet,1<<4) ///< Hidden pointer to structure to return
DECLARE_LLVM_ATTRIBUTE(NoUnwind,1<<5) ///< Function doesn't unwind stack
DECLARE_LLVM_ATTRIBUTE(NoAlias,1<<6) ///< Considered to not alias after call
DECLARE_LLVM_ATTRIBUTE(ByVal,1<<7) ///< Pass structure by value
DECLARE_LLVM_ATTRIBUTE(Nest,1<<8) ///< Nested function static chain
DECLARE_LLVM_ATTRIBUTE(ReadNone,1<<9) ///< Function does not access memory
DECLARE_LLVM_ATTRIBUTE(ReadOnly,1<<10) ///< Function only reads from memory
DECLARE_LLVM_ATTRIBUTE(NoInline,1<<11) ///< inline=never
DECLARE_LLVM_ATTRIBUTE(AlwaysInline,1<<12) ///< inline=always
DECLARE_LLVM_ATTRIBUTE(OptimizeForSize,1<<13) ///< opt_size
DECLARE_LLVM_ATTRIBUTE(StackProtect,1<<14) ///< Stack protection.
DECLARE_LLVM_ATTRIBUTE(StackProtectReq,1<<15) ///< Stack protection required.
DECLARE_LLVM_ATTRIBUTE(Alignment,31<<16) ///< Alignment of parameter (5 bits)
// stored as log2 of alignment with +1 bias
// 0 means unaligned different from align 1
DECLARE_LLVM_ATTRIBUTE(NoCapture,1<<21) ///< Function creates no aliases of pointer
DECLARE_LLVM_ATTRIBUTE(NoRedZone,1<<22) /// disable redzone
DECLARE_LLVM_ATTRIBUTE(NoImplicitFloat,1<<23) /// disable implicit floating point
/// instructions.
DECLARE_LLVM_ATTRIBUTE(Naked,1<<24) ///< Naked function
DECLARE_LLVM_ATTRIBUTE(InlineHint,1<<25) ///< source said inlining was
///desirable
DECLARE_LLVM_ATTRIBUTE(StackAlignment,7<<26) ///< Alignment of stack for
///function (3 bits) stored as log2
///of alignment with +1 bias
///0 means unaligned (different from
///alignstack= {1))
DECLARE_LLVM_ATTRIBUTE(ReturnsTwice,1<<29) ///< Function can return twice
DECLARE_LLVM_ATTRIBUTE(UWTable,1<<30) ///< Function must be in a unwind
///table
DECLARE_LLVM_ATTRIBUTE(NonLazyBind,1U<<31) ///< Function is called early and/or
/// often, so lazy binding isn't
/// worthwhile.
DECLARE_LLVM_ATTRIBUTE(AddressSafety,1ULL<<32) ///< Address safety checking is on.
#undef DECLARE_LLVM_ATTRIBUTE
/// Note that 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.
/// @brief Attributes that only apply to function parameters.
const AttrConst ParameterOnly = {ByVal_i | Nest_i |
StructRet_i | NoCapture_i};
/// @brief Attributes that may be applied to the function itself. These cannot
/// be used on return values or function parameters.
const AttrConst FunctionOnly = {NoReturn_i | NoUnwind_i | ReadNone_i |
ReadOnly_i | NoInline_i | AlwaysInline_i | OptimizeForSize_i |
StackProtect_i | StackProtectReq_i | NoRedZone_i | NoImplicitFloat_i |
Naked_i | InlineHint_i | StackAlignment_i |
UWTable_i | NonLazyBind_i | ReturnsTwice_i | AddressSafety_i};
/// @brief Parameter attributes that do not apply to vararg call arguments.
const AttrConst VarArgsIncompatible = {StructRet_i};
/// @brief Attributes that are mutually incompatible.
const AttrConst MutuallyIncompatible[4] = {
{ByVal_i | InReg_i | Nest_i | StructRet_i},
{ZExt_i | SExt_i},
{ReadNone_i | ReadOnly_i},
{NoInline_i | AlwaysInline_i}
};
/// @brief Which attributes cannot be applied to a type.
Attributes typeIncompatible(Type *Ty);
/// This turns an int alignment (a power of 2, normally) into the
/// form used internally in Attributes.
inline Attributes constructAlignmentFromInt(unsigned i) {
// Default alignment, allow the target to define how to align it.
if (i == 0)
return None;
assert(isPowerOf2_32(i) && "Alignment must be a power of two.");
assert(i <= 0x40000000 && "Alignment too large.");
return Attributes((Log2_32(i)+1) << 16);
}
/// This returns the alignment field of an attribute as a byte alignment value.
inline unsigned getAlignmentFromAttrs(Attributes A) {
Attributes Align = A & Attribute::Alignment;
if (!Align)
return 0;
return 1U << ((Align.Raw() >> 16) - 1);
}
/// This turns an int stack alignment (which must be a power of 2) into
/// the form used internally in Attributes.
inline Attributes constructStackAlignmentFromInt(unsigned i) {
// Default alignment, allow the target to define how to align it.
if (i == 0)
return None;
assert(isPowerOf2_32(i) && "Alignment must be a power of two.");
assert(i <= 0x100 && "Alignment too large.");
return Attributes((Log2_32(i)+1) << 26);
}
/// This returns the stack alignment field of an attribute as a byte alignment
/// value.
inline unsigned getStackAlignmentFromAttrs(Attributes A) {
Attributes StackAlign = A & Attribute::StackAlignment;
if (!StackAlign)
return 0;
return 1U << ((StackAlign.Raw() >> 26) - 1);
}
/// 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.
inline uint64_t encodeLLVMAttributesForBitcode(Attributes Attrs) {
// FIXME: It doesn't make sense to store the alignment information as an
// expanded out value, we should store it as a log2 value. However, we can't
// just change that here without breaking bitcode compatibility. If this ever
// becomes a problem in practice, we should introduce new tag numbers in the
// bitcode file and have those tags use a more efficiently encoded alignment
// field.
// Store the alignment in the bitcode as a 16-bit raw value instead of a
// 5-bit log2 encoded value. Shift the bits above the alignment up by
// 11 bits.
uint64_t EncodedAttrs = Attrs.Raw() & 0xffff;
if (Attrs & Attribute::Alignment)
EncodedAttrs |= (1ull << 16) <<
(((Attrs & Attribute::Alignment).Raw()-1) >> 16);
EncodedAttrs |= (Attrs.Raw() & (0xfffull << 21)) << 11;
return EncodedAttrs;
}
/// 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'.
inline Attributes decodeLLVMAttributesForBitcode(uint64_t EncodedAttrs) {
// The alignment is stored as a 16-bit raw value from bits 31--16.
// We shift the bits above 31 down by 11 bits.
unsigned Alignment = (EncodedAttrs & (0xffffull << 16)) >> 16;
assert((!Alignment || isPowerOf2_32(Alignment)) &&
"Alignment must be a power of two.");
Attributes Attrs(EncodedAttrs & 0xffff);
if (Alignment)
Attrs |= Attribute::constructAlignmentFromInt(Alignment);
Attrs |= Attributes((EncodedAttrs & (0xfffull << 32)) >> 11);
return Attrs;
}
/// The set of Attributes 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 attribute bits to text
std::string getAsString(Attributes Attrs);
} // end namespace Attribute
/// This is just a pair of values to associate a set of attributes
/// with an index.
struct AttributeWithIndex {
Attributes 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(unsigned Idx, Attributes Attrs) {
AttributeWithIndex P;
P.Index = Idx;
P.Attrs = Attrs;
return P;
}
};
//===----------------------------------------------------------------------===//
// AttrListPtr Smart Pointer
//===----------------------------------------------------------------------===//
class AttributeListImpl;
/// AttrListPtr - This class manages the ref count for the opaque
/// AttributeListImpl object and provides accessors for it.
class AttrListPtr {
/// AttrList - The attributes that we are managing. This can be null
/// to represent the empty attributes list.
AttributeListImpl *AttrList;
public:
AttrListPtr() : AttrList(0) {}
AttrListPtr(const AttrListPtr &P);
const AttrListPtr &operator=(const AttrListPtr &RHS);
~AttrListPtr();
//===--------------------------------------------------------------------===//
// Attribute List Construction and Mutation
//===--------------------------------------------------------------------===//
/// get - Return a Attributes list with the specified parameters in it.
static AttrListPtr get(ArrayRef<AttributeWithIndex> Attrs);
/// addAttr - Add the specified attribute at the specified index to this
/// attribute list. Since attribute lists are immutable, this
/// returns the new list.
AttrListPtr addAttr(unsigned Idx, Attributes Attrs) const;
/// removeAttr - Remove the specified attribute at the specified index from
/// this attribute list. Since attribute lists are immutable, this
/// returns the new list.
AttrListPtr removeAttr(unsigned Idx, Attributes Attrs) const;
//===--------------------------------------------------------------------===//
// Attribute List Accessors
//===--------------------------------------------------------------------===//
/// getParamAttributes - The attributes for the specified index are
/// returned.
Attributes getParamAttributes(unsigned Idx) const {
assert (Idx && Idx != ~0U && "Invalid parameter index!");
return getAttributes(Idx);
}
/// getRetAttributes - The attributes for the ret value are
/// returned.
Attributes getRetAttributes() const {
return getAttributes(0);
}
/// getFnAttributes - The function attributes are returned.
Attributes getFnAttributes() const {
return getAttributes(~0U);
}
/// paramHasAttr - Return true if the specified parameter index has the
/// specified attribute set.
bool paramHasAttr(unsigned Idx, Attributes Attr) const {
return getAttributes(Idx) & Attr;
}
/// getParamAlignment - Return the alignment for the specified function
/// parameter.
unsigned getParamAlignment(unsigned Idx) const {
return Attribute::getAlignmentFromAttrs(getAttributes(Idx));
}
/// hasAttrSomewhere - Return true if the specified attribute is set for at
/// least one parameter or for the return value.
bool hasAttrSomewhere(Attributes Attr) const;
/// operator==/!= - Provide equality predicates.
bool operator==(const AttrListPtr &RHS) const
{ return AttrList == RHS.AttrList; }
bool operator!=(const AttrListPtr &RHS) const
{ return AttrList != RHS.AttrList; }
void dump() const;
//===--------------------------------------------------------------------===//
// Attribute List Introspection
//===--------------------------------------------------------------------===//
/// getRawPointer - 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.
/// isEmpty - Return true if there are no attributes.
///
bool isEmpty() const {
return AttrList == 0;
}
/// getNumSlots - 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;
/// getSlot - Return the AttributeWithIndex at the specified slot. This
/// holds a index number plus a set of attributes.
const AttributeWithIndex &getSlot(unsigned Slot) const;
private:
explicit AttrListPtr(AttributeListImpl *L);
/// getAttributes - The attributes for the specified index are
/// returned. Attributes for the result are denoted with Idx = 0.
Attributes getAttributes(unsigned Idx) const;
};
} // End llvm namespace
#endif