-//===-- llvm/Attributes.h - Container for Attributes ---*---------- C++ -*-===//
+//===-- llvm/Attributes.h - Container for Attributes ------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
#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.
-typedef unsigned Attributes;
-
+class Attributes {
+ public:
+ Attributes() : Bits(0) { }
+ explicit Attributes(uint64_t Val) : Bits(Val) { }
+ /*implicit*/ Attributes(Attribute::AttrConst Val) : Bits(Val.v) { }
+ // This is a "safe bool() operator".
+ operator const void *() const { return Bits ? this : 0; }
+ bool isEmptyOrSingleton() const { return (Bits & (Bits - 1)) == 0; }
+ 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
+/// 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.
-const Attributes None = 0; ///< No attributes have been set
-const Attributes ZExt = 1<<0; ///< Zero extended before/after call
-const Attributes SExt = 1<<1; ///< Sign extended before/after call
-const Attributes NoReturn = 1<<2; ///< Mark the function as not returning
-const Attributes InReg = 1<<3; ///< Force argument to be passed in register
-const Attributes StructRet = 1<<4; ///< Hidden pointer to structure to return
-const Attributes NoUnwind = 1<<5; ///< Function doesn't unwind stack
-const Attributes NoAlias = 1<<6; ///< Considered to not alias after call
-const Attributes ByVal = 1<<7; ///< Pass structure by value
-const Attributes Nest = 1<<8; ///< Nested function static chain
-const Attributes ReadNone = 1<<9; ///< Function does not access memory
-const Attributes ReadOnly = 1<<10; ///< Function only reads from memory
-const Attributes NoInline = 1<<11; // inline=never
-const Attributes AlwaysInline = 1<<12; // inline=always
-const Attributes OptimizeForSize = 1<<13; // opt_size
-const Attributes Alignment = 0xffff<<16; ///< Alignment of parameter (16 bits)
- // 0 = unknown, else in clear (not log)
-
+// 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 Attributes ParameterOnly = ByVal | Nest | StructRet;
+const AttrConst ParameterOnly = {ByVal_i | Nest_i |
+ StructRet_i | NoCapture_i};
-/// @brief Attributes that only apply to function.
-const Attributes FunctionOnly = NoReturn | NoUnwind | ReadNone | ReadOnly |
- NoInline | AlwaysInline | OptimizeForSize;
+/// @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 Attributes VarArgsIncompatible = StructRet;
+const AttrConst VarArgsIncompatible = {StructRet_i};
/// @brief Attributes that are mutually incompatible.
-const Attributes MutuallyIncompatible[4] = {
- ByVal | InReg | Nest | StructRet,
- ZExt | SExt,
- ReadNone | ReadOnly,
- NoInline | AlwaysInline
+const AttrConst MutuallyIncompatible[5] = {
+ {ByVal_i | Nest_i | StructRet_i},
+ {ByVal_i | Nest_i | InReg_i },
+ {ZExt_i | SExt_i},
+ {ReadNone_i | ReadOnly_i},
+ {NoInline_i | AlwaysInline_i}
};
/// @brief Which attributes cannot be applied to a type.
-Attributes typeIncompatible(const Type *Ty);
+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) {
- return (i << 16);
+ // 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.
+/// 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.
+/// 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;
return P;
}
};
-
+
//===----------------------------------------------------------------------===//
// AttrListPtr Smart Pointer
//===----------------------------------------------------------------------===//
class AttributeListImpl;
-
-/// AttrListPtr - This class manages the ref count for the opaque
+
+/// 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
AttrListPtr(const AttrListPtr &P);
const AttrListPtr &operator=(const AttrListPtr &RHS);
~AttrListPtr();
-
+
//===--------------------------------------------------------------------===//
// Attribute List Construction and Mutation
//===--------------------------------------------------------------------===//
-
- /// get - Return a Attributes list with the specified parameter in it.
- static AttrListPtr get(const AttributeWithIndex *Attr, unsigned NumAttrs);
-
- /// get - Return a Attribute list with the parameters specified by the
- /// consecutive random access iterator range.
- template <typename Iter>
- static AttrListPtr get(const Iter &I, const Iter &E) {
- if (I == E) return AttrListPtr(); // Empty list.
- return get(&*I, static_cast<unsigned>(E-I));
- }
+
+ /// 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.
+ /// 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.
+ /// returned.
Attributes getRetAttributes() const {
return getAttributes(0);
}
- /// getFnAttributes - The function attributes are returned.
+ /// getFnAttributes - The function attributes are returned.
Attributes getFnAttributes() const {
- return getAttributes(~0);
+ 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 (getAttributes(Idx) & Attribute::Alignment) >> 16;
+ 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; }
-
+ 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.
+ /// 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.
+
+ /// 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);
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