+ /// constructAlignmentFromInt - This turns an int alignment (a power of 2,
+ /// normally) into the form used internally in Attributes.
+ static Attributes constructAlignmentFromInt(unsigned i) {
+ // Default alignment, allow the target to define how to align it.
+ if (i == 0)
+ return Attribute::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);
+ }
+
+ /// constructStackAlignmentFromInt - This turns an int stack alignment (which
+ /// must be a power of 2) into the form used internally in Attributes.
+ static Attributes constructStackAlignmentFromInt(unsigned i) {
+ // Default alignment, allow the target to define how to align it.
+ if (i == 0)
+ return Attribute::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);
+ }
+
+ /// @brief Which attributes cannot be applied to a type.
+ static Attributes typeIncompatible(Type *Ty);
+
+ /// encodeLLVMAttributesForBitcode - 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(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.hasAttribute(Attributes::Alignment))
+ EncodedAttrs |= (1ULL << 16) <<
+ (((Attrs.Raw() & Attribute::Alignment_i) - 1) >> 16);
+ EncodedAttrs |= (Attrs.Raw() & (0xfffULL << 21)) << 11;
+ return EncodedAttrs;
+ }
+
+ /// decodeLLVMAttributesForBitcode - 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 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 |= Attributes::constructAlignmentFromInt(Alignment);
+ Attrs |= Attributes((EncodedAttrs & (0xfffULL << 32)) >> 11);
+ return Attrs;
+ }
+
+ /// getAsString - 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() const;
+};
+
+//===----------------------------------------------------------------------===//
+// AttributeWithIndex
+//===----------------------------------------------------------------------===//
+
+/// AttributeWithIndex - This is just a pair of values to associate a set of
+/// attributes with an index.