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Reflection: Fix class layout start offset calculations

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Fixes <rdar://problem/29115967>.
This commit is contained in:
Slava Pestov
2016-11-09 18:36:01 -08:00
parent 83692bb398
commit db79762c3b
29 changed files with 262 additions and 104 deletions
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75
include/swift/Remote/MetadataReader.h
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@@ -564,18 +564,18 @@ public:
/// instance size and alignment.
std::tuple<bool, unsigned, unsigned>
readInstanceSizeAndAlignmentFromClassMetadata(StoredPointer MetadataAddress) {
auto superMeta = readMetadata(MetadataAddress);
if (!superMeta || superMeta->getKind() != MetadataKind::Class)
auto meta = readMetadata(MetadataAddress);
if (!meta || meta->getKind() != MetadataKind::Class)
return std::make_tuple(false, 0, 0);
auto super = cast<TargetClassMetadata<Runtime>>(superMeta);
auto classMeta = cast<TargetClassMetadata<Runtime>>(meta);
// See swift_initClassMetadata_UniversalStrategy()
uint32_t size, align;
if (super->isTypeMetadata()) {
size = super->getInstanceSize();
align = super->getInstanceAlignMask() + 1;
} else {
// If this class is defined in Objective-C, return the value of the
// InstanceStart field from the ROData.
if (!classMeta->isTypeMetadata()) {
// The following algorithm only works on the non-fragile Apple runtime.
// Grab the RO-data pointer. This part is not ABI.
@@ -583,14 +583,71 @@ public:
if (!roDataPtr)
return std::make_tuple(false, 0, 0);
auto address = roDataPtr + sizeof(uint32_t) * 2;
// Get the address of the InstanceStart field.
auto address = roDataPtr + sizeof(uint32_t) * 1;
align = 16; // malloc alignment guarantee
align = 16;
if (!Reader->readInteger(RemoteAddress(address), &size))
return std::make_tuple(false, 0, 0);
assert((size & (align - 1)) == 0);
return std::make_tuple(true, size, align);
}
// Otherwise, it is a Swift class. Get the superclass.
auto superAddr = readSuperClassFromClassMetadata(MetadataAddress);
if (superAddr) {
auto superMeta = readMetadata(superAddr);
if (!superMeta || superMeta->getKind() != MetadataKind::Class)
return std::make_tuple(false, 0, 0);
auto superclassMeta = cast<TargetClassMetadata<Runtime>>(superMeta);
// If the superclass is an Objective-C class, we start layout
// from the InstanceSize of the superclass, aligned up to
// 16 bytes.
if (superclassMeta->isTypeMetadata()) {
// Superclass is a Swift class. Get the size of an instance,
// and start layout from that.
size = superclassMeta->getInstanceSize();
align = 1;
return std::make_tuple(true, size, align);
}
std::string superName;
if (!readObjCClassName(superAddr, superName))
return std::make_tuple(false, 0, 0);
if (superName != "SwiftObject") {
// Grab the RO-data pointer. This part is not ABI.
StoredPointer roDataPtr = readObjCRODataPtr(superAddr);
if (!roDataPtr)
return std::make_tuple(false, 0, 0);
// Get the address of the InstanceSize field.
auto address = roDataPtr + sizeof(uint32_t) * 2;
// malloc alignment boundary.
align = 16;
if (!Reader->readInteger(RemoteAddress(address), &size))
return std::make_tuple(false, 0, 0);
// Round up to the alignment boundary.
size = (size + (align - 1)) & ~(align - 1);
return std::make_tuple(true, size, align);
}
// Fall through.
}
// No superclass, just an object header. 12 bytes on 32-bit, 16 on 64-bit
size = Reader->getPointerSize() + sizeof(uint64_t);
align = 1;
return std::make_tuple(true, size, align);
}