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Fix reuse of the payload area when the discriminator != 0

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This commit is contained in:
Mike Ash
2020-01-09 16:50:59 -05:00
committed by Tim Kientzle
parent 57f54dd1a3
commit b80e33b514
3 changed files with 185 additions and 33 deletions
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53
include/swift/Reflection/ReflectionContext.h
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@@ -751,44 +751,51 @@ public:
return false;
unsigned long NonPayloadCaseCount = FieldCount - 1;
unsigned long PayloadExtraInhabitants = PayloadCase.TI.getNumExtraInhabitants();
unsigned discriminator = 0;
unsigned Discriminator = 0;
auto PayloadSize = PayloadCase.TI.getSize();
if (NonPayloadCaseCount >= PayloadExtraInhabitants) {
// There are more cases than inhabitants, we need a separate discriminator.
auto TagInfo = getEnumTagCounts(PayloadSize, NonPayloadCaseCount, 1);
auto TagSize = TagInfo.numTagBytes;
auto TagAddress = RemoteAddress(EnumAddress.getAddressData() + PayloadSize);
if (!getReader().readInteger(TagAddress, TagSize, &discriminator))
return false;
}
if (PayloadExtraInhabitants == 0) {
// Payload has no XI, so discriminator fully determines the case
*CaseIndex = discriminator;
return true;
} else if (discriminator == 0) {
// The value overlays the payload ... ask the payload to decode it.
int t;
if (!PayloadCase.TI.readExtraInhabitantIndex(getReader(), EnumAddress, &t)) {
if (!getReader().readInteger(TagAddress, TagSize, &Discriminator)) {
printf(">>>> readXI failed to read discriminator\n\n");
return false;
}
if (t < 0) {
}
if (PayloadSize == 0) {
// Payload carries no information, so discriminator fully determines the case
*CaseIndex = Discriminator;
return true;
} else if (Discriminator == 0) {
// The payload area carries all the information...
if (PayloadExtraInhabitants == 0) {
*CaseIndex = 0;
return true;
} else if ((unsigned long)t <= NonPayloadCaseCount) {
*CaseIndex = t + 1;
}
int XITag = 0;
if (!PayloadCase.TI.readExtraInhabitantIndex(getReader(), EnumAddress, &XITag)) {
return false;
}
if (XITag < 0) { // Valid (not extra) inhabitant
*CaseIndex = 0; // Payload case is always #0
return true;
} else if ((unsigned)XITag <= NonPayloadCaseCount) {
*CaseIndex = XITag + 1;
return true;
}
return false;
} else {
// The entire payload area is available for additional cases:
auto TagSize = std::max(PayloadSize, 4U); // XXX TODO XXX CHECK THIS
auto offset = 1 + PayloadExtraInhabitants; // Cases coded with discriminator = 0
unsigned casesInPayload = 1 << (TagSize * 8U);
unsigned payloadCode;
if (!getReader().readInteger(EnumAddress, TagSize, &payloadCode))
// No payload: Payload area is reused for more cases
unsigned PayloadTag = 0;
auto PayloadTagSize = std::min(PayloadSize, decltype(PayloadSize)(sizeof(PayloadTag)));
if (!getReader().readInteger(EnumAddress, PayloadTagSize, &PayloadTag)) {
return false;
*CaseIndex = offset + (discriminator - 1) * casesInPayload + payloadCode;
}
auto XICases = 1U + PayloadExtraInhabitants; // Cases coded with XIs when discriminator = 0
auto PayloadCases = 1U << (PayloadTagSize * 8U);
*CaseIndex = XICases + (Discriminator - 1) * PayloadCases + PayloadTag;
return true;
}
}