diff options
Diffstat (limited to 'lib/Bitcode')
| -rw-r--r-- | lib/Bitcode/Reader/BitcodeReader.cpp | 26 | ||||
| -rw-r--r-- | lib/Bitcode/Writer/BitcodeWriter.cpp | 30 |
2 files changed, 49 insertions, 7 deletions
diff --git a/lib/Bitcode/Reader/BitcodeReader.cpp b/lib/Bitcode/Reader/BitcodeReader.cpp index ca299c007c..6ab7011187 100644 --- a/lib/Bitcode/Reader/BitcodeReader.cpp +++ b/lib/Bitcode/Reader/BitcodeReader.cpp @@ -428,6 +428,26 @@ Type *BitcodeReader::getTypeByID(unsigned ID) { // Functions for parsing blocks from the bitcode file //===----------------------------------------------------------------------===// + +/// \brief This fills an AttrBuilder object with the LLVM attributes that have +/// been decoded from the given integer. This function must stay in sync with +/// 'encodeLLVMAttributesForBitcode'. +static void decodeLLVMAttributesForBitcode(AttrBuilder &B, + uint64_t EncodedAttrs) { + // FIXME: Remove in 4.0. + + // 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."); + + if (Alignment) + B.addAlignmentAttr(Alignment); + B.addRawValue(((EncodedAttrs & (0xffffULL << 32)) >> 11) | + (EncodedAttrs & 0xffff)); +} + bool BitcodeReader::ParseAttributeBlock() { if (Stream.EnterSubBlock(bitc::PARAMATTR_BLOCK_ID)) return Error("Malformed block record"); @@ -459,14 +479,14 @@ bool BitcodeReader::ParseAttributeBlock() { switch (Stream.readRecord(Entry.ID, Record)) { default: // Default behavior: ignore. break; - case bitc::PARAMATTR_CODE_ENTRY: { // ENTRY: [paramidx0, attr0, ...] + case bitc::PARAMATTR_CODE_ENTRY_OLD: { // ENTRY: [paramidx0, attr0, ...] + // FIXME: Remove in 4.0. if (Record.size() & 1) return Error("Invalid ENTRY record"); for (unsigned i = 0, e = Record.size(); i != e; i += 2) { AttrBuilder B; - AttributeFuncs::decodeLLVMAttributesForBitcode(Context, B, - Record[i+1]); + decodeLLVMAttributesForBitcode(B, Record[i+1]); Attrs.push_back(AttributeSet::get(Context, Record[i], B)); } diff --git a/lib/Bitcode/Writer/BitcodeWriter.cpp b/lib/Bitcode/Writer/BitcodeWriter.cpp index b6c2bc0f75..c6d0371de7 100644 --- a/lib/Bitcode/Writer/BitcodeWriter.cpp +++ b/lib/Bitcode/Writer/BitcodeWriter.cpp @@ -161,7 +161,30 @@ static void WriteStringRecord(unsigned Code, StringRef Str, Stream.EmitRecord(Code, Vals, AbbrevToUse); } -// Emit information about parameter attributes. +/// \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. +/// N.B. This should be used only by the bitcode writer! +static uint64_t encodeLLVMAttributesForBitcode(AttributeSet Attrs, + unsigned Index) { + // FIXME: Remove in 4.0! + + // 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(Index) & 0xffff; + if (Attrs.hasAttribute(Index, Attribute::Alignment)) + EncodedAttrs |= Attrs.getParamAlignment(Index) << 16; + EncodedAttrs |= (Attrs.Raw(Index) & (0xffffULL << 21)) << 11; + return EncodedAttrs; +} + static void WriteAttributeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) { const std::vector<AttributeSet> &Attrs = VE.getAttributes(); @@ -175,12 +198,11 @@ static void WriteAttributeTable(const ValueEnumerator &VE, for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i) { unsigned Index = A.getSlotIndex(i); Record.push_back(Index); - Record.push_back(AttributeFuncs:: - encodeLLVMAttributesForBitcode(A.getSlotAttributes(i), + Record.push_back(encodeLLVMAttributesForBitcode(A.getSlotAttributes(i), Index)); } - Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record); + Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY_OLD, Record); Record.clear(); } |