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[6.0] [IRGen] Fix misalignment of conditional invertible requirement counts #74014

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Merged
merged 2 commits into from
May 30, 2024
Merged

[6.0] [IRGen] Fix misalignment of conditional invertible requirement counts #74014

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e543a47
Merge pull request #73277 from Azoy/fix-conditional-invertible
Azoy May 1, 2024
5cb1779
Merge pull request #73384 from Azoy/popcount-but-for-real
Azoy May 2, 2024
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3 changes: 2 additions & 1 deletion include/swift/ABI/GenericContext.h
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Original file line number Diff line number Diff line change
Expand Up @@ -23,6 +23,7 @@
#include "swift/ABI/MetadataRef.h"
#include "swift/ABI/InvertibleProtocols.h"
#include "swift/ABI/TrailingObjects.h"
#include "swift/Basic/MathUtils.h"
#include "swift/Demangling/Demangle.h"

namespace swift {
Expand Down Expand Up @@ -696,7 +697,7 @@ class TrailingGenericContextObjects<TargetSelf<Runtime>,
if (!asSelf()->hasConditionalInvertedProtocols())
return 0;

return countBitsUsed(getConditionalInvertedProtocols().rawBits());
return popcount(getConditionalInvertedProtocols().rawBits());
}

size_t numTrailingObjects(
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21 changes: 21 additions & 0 deletions include/swift/Basic/MathUtils.h
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Expand Up @@ -17,7 +17,13 @@
#ifndef SWIFT_BASIC_MATH_UTILS_H
#define SWIFT_BASIC_MATH_UTILS_H

#include "Compiler.h"
#include <cstddef>
#include <cstdint>

#if SWIFT_COMPILER_IS_MSVC
#include <intrin.h>
#endif

namespace swift {

Expand All @@ -33,6 +39,21 @@ static inline size_t roundUpToAlignMask(size_t size, size_t alignMask) {
return (size + alignMask) & ~alignMask;
}

static inline unsigned popcount(unsigned value) {
#if SWIFT_COMPILER_IS_MSVC && (defined(_M_IX86) || defined(_M_X64))
// The __popcnt intrinsic is only available when targetting x86{_64} with MSVC.
return __popcnt(value);
#elif __has_builtin(__builtin_popcount)
return __builtin_popcount(value);
#else
// From llvm/ADT/bit.h which the runtime doesn't have access to (yet?)
uint32_t v = value;
v = v - ((v >> 1) & 0x55555555);
v = (v & 0x33333333) + ((v >> 2) & 0x33333333);
return int(((v + (v >> 4) & 0xF0F0F0F) * 0x1010101) >> 24);
#endif
}

} // namespace swift

#endif // #ifndef SWIFT_BASIC_MATH_UTILS_H
7 changes: 7 additions & 0 deletions lib/IRGen/GenMeta.cpp
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Expand Up @@ -1334,6 +1334,13 @@ namespace {
B.addPlaceholderWithSize(IGM.Int16Ty));
}

// The conditional invertible protocol set is alone as a 16 bit slot, so
// an even amount of conditional invertible protocols will cause an uneven
// alignment.
if ((numProtocols & 1) == 0) {
B.addInt16(0);
}

// Emit the generic requirements for the conditional conformance
// to each invertible protocol.
auto nominal = cast<NominalTypeDecl>(Type);
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