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[Runtime] Abstract handling of simple single payload enum handling #67067

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merged 1 commit into from
Jul 1, 2023
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[Runtime] Abstract handling of simple single payload enum handling #67067

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63 changes: 43 additions & 20 deletions stdlib/public/runtime/BytecodeLayouts.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -659,25 +659,45 @@ extern "C" unsigned swift_singletonEnum_getEnumTag(swift::OpaqueValue *address,
return 0;
}

extern "C"
unsigned swift_enumSimple_getEnumTag(swift::OpaqueValue *address,
const Metadata *metadata) {
auto addr = reinterpret_cast<uint8_t *>(address);
LayoutStringReader reader{metadata->getLayoutString(),
layoutStringHeaderSize + sizeof(uint64_t)};
template <typename T>
static inline T handleSinglePayloadEnumSimpleTag(
LayoutStringReader &reader, uint8_t *addr,
std::function<std::optional<T>(size_t, size_t, uint8_t)>
extraTagBytesHandler,
std::function<T(size_t, uint64_t, uint8_t, unsigned, size_t, uint8_t)>
xiHandler) {
auto byteCountsAndOffset = reader.readBytes<uint64_t>();
auto extraTagBytesPattern = (uint8_t)(byteCountsAndOffset >> 62);
auto xiTagBytesPattern = ((uint8_t)(byteCountsAndOffset >> 59)) & 0x7;
auto xiTagBytesOffset =
byteCountsAndOffset & std::numeric_limits<uint32_t>::max();
auto numExtraTagBytes = 1 << (extraTagBytesPattern - 1);
auto payloadSize = reader.readBytes<size_t>();
auto zeroTagValue = reader.readBytes<uint64_t>();
auto payloadNumExtraInhabitants = reader.readBytes<size_t>();

if (extraTagBytesPattern) {
auto extraTagBytes = 1 << (extraTagBytesPattern - 1);
auto payloadSize = reader.readBytes<size_t>();
auto tagBytes = readTagBytes(addr + payloadSize, extraTagBytes);
if (auto result = extraTagBytesHandler(payloadNumExtraInhabitants,
payloadSize, numExtraTagBytes)) {
return *result;
}
}

return xiHandler(payloadNumExtraInhabitants, zeroTagValue, xiTagBytesPattern,
xiTagBytesOffset, payloadSize, numExtraTagBytes);
}

extern "C" unsigned swift_enumSimple_getEnumTag(swift::OpaqueValue *address,
const Metadata *metadata) {
auto addr = reinterpret_cast<uint8_t *>(address);
LayoutStringReader reader{metadata->getLayoutString(),
layoutStringHeaderSize + sizeof(uint64_t)};

auto extraTagBytesHandler =
[addr](size_t payloadNumExtraInhabitants, size_t payloadSize,
uint8_t numExtraTagBytes) -> std::optional<unsigned> {
auto tagBytes = readTagBytes(addr + payloadSize, numExtraTagBytes);
if (tagBytes) {
reader.skip(sizeof(uint64_t));
auto payloadNumExtraInhabitants = reader.readBytes<size_t>();
unsigned caseIndexFromExtraTagBits =
payloadSize >= 4 ? 0 : (tagBytes - 1U) << (payloadSize * 8U);
unsigned caseIndexFromValue = loadEnumElement(addr, payloadSize);
Expand All @@ -686,24 +706,27 @@ unsigned swift_enumSimple_getEnumTag(swift::OpaqueValue *address,
payloadNumExtraInhabitants;
return noPayloadIndex + 1;
}
} else {
reader.skip(sizeof(size_t));
}

if (xiTagBytesPattern) {
auto zeroTagValue = reader.readBytes<uint64_t>();
auto xiTagValues = reader.readBytes<size_t>();
return std::nullopt;
};

auto xihandler = [addr](size_t payloadNumExtraInhabitants,
uint64_t zeroTagValue, uint8_t xiTagBytesPattern,
unsigned xiTagBytesOffset, size_t payloadSize,
uint8_t numExtraTagBytes) -> unsigned {
auto xiTagBytes = 1 << (xiTagBytesPattern - 1);
uint64_t tagBytes =
readTagBytes(addr + xiTagBytesOffset, xiTagBytes) -
zeroTagValue;
if (tagBytes < xiTagValues) {
if (tagBytes < payloadNumExtraInhabitants) {
return tagBytes + 1;
}
}

return 0;
return 0;
};

return handleSinglePayloadEnumSimpleTag<unsigned>(
reader, addr, extraTagBytesHandler, xihandler);
}

extern "C"
Expand Down