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[Runtime] Avoid function pointer indirection in refcounting functions.

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Functions like swift_retain call through a function pointer so that Instruments can interpose. This slows down the common case where there is no interposition. Instead, initialize the function pointers to NULL and call through directly to the real implementation when it's NULL. The compiler is smart enough to inline this call and the result is a single conditional branch rather than a function pointer call.

rdar://problem/18307425
This commit is contained in:
Mike Ash
2019-08-06 14:29:51 -04:00
parent 6674043454
commit 9fd03e24ad
1 changed files with 52 additions and 32 deletions
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84
stdlib/public/runtime/HeapObject.cpp
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@@ -72,12 +72,6 @@ static inline bool isValidPointerForNativeRetain(const void *p) {
#endif
}
HeapObject *swift::swift_allocObject(HeapMetadata const *metadata,
size_t requiredSize,
size_t requiredAlignmentMask) {
return _swift_allocObject(metadata, requiredSize, requiredAlignmentMask);
}
static HeapObject *_swift_allocObject_(HeapMetadata const *metadata,
size_t requiredSize,
size_t requiredAlignmentMask) {
@@ -98,7 +92,18 @@ static HeapObject *_swift_allocObject_(HeapMetadata const *metadata,
return object;
}
auto swift::_swift_allocObject = _swift_allocObject_;
HeapObject *swift::swift_allocObject(HeapMetadata const *metadata,
size_t requiredSize,
size_t requiredAlignmentMask) {
if (SWIFT_UNLIKELY(_swift_allocObject))
return _swift_allocObject(metadata, requiredSize, requiredAlignmentMask);
else
return _swift_allocObject_(metadata, requiredSize, requiredAlignmentMask);
}
HeapObject *(*swift::_swift_allocObject)(HeapMetadata const *metadata,
size_t requiredSize,
size_t requiredAlignmentMask);
HeapObject *
swift::swift_initStackObject(HeapMetadata const *metadata,
@@ -292,10 +297,6 @@ HeapObject *swift::swift_allocEmptyBox() {
extern "C" LLVM_LIBRARY_VISIBILITY LLVM_ATTRIBUTE_NOINLINE LLVM_ATTRIBUTE_USED
void _swift_release_dealloc(HeapObject *object);
HeapObject *swift::swift_retain(HeapObject *object) {
return _swift_retain(object);
}
static HeapObject *_swift_retain_(HeapObject *object) {
SWIFT_RT_TRACK_INVOCATION(object, swift_retain);
if (isValidPointerForNativeRetain(object))
@@ -303,7 +304,14 @@ static HeapObject *_swift_retain_(HeapObject *object) {
return object;
}
auto swift::_swift_retain = _swift_retain_;
HeapObject *swift::swift_retain(HeapObject *object) {
if (SWIFT_UNLIKELY(_swift_retain))
return _swift_retain(object);
else
return _swift_retain_(object);
}
HeapObject *(*swift::_swift_retain)(HeapObject *object);
HeapObject *swift::swift_nonatomic_retain(HeapObject *object) {
SWIFT_RT_TRACK_INVOCATION(object, swift_nonatomic_retain);
@@ -312,10 +320,6 @@ HeapObject *swift::swift_nonatomic_retain(HeapObject *object) {
return object;
}
HeapObject *swift::swift_retain_n(HeapObject *object, uint32_t n) {
return _swift_retain_n(object, n);
}
static HeapObject *_swift_retain_n_(HeapObject *object, uint32_t n) {
SWIFT_RT_TRACK_INVOCATION(object, swift_retain_n);
if (isValidPointerForNativeRetain(object))
@@ -323,7 +327,14 @@ static HeapObject *_swift_retain_n_(HeapObject *object, uint32_t n) {
return object;
}
auto swift::_swift_retain_n = _swift_retain_n_;
HeapObject *swift::swift_retain_n(HeapObject *object, uint32_t n) {
if (SWIFT_UNLIKELY(_swift_retain_n))
return _swift_retain_n(object, n);
else
return _swift_retain_n_(object, n);
}
HeapObject *(*swift::_swift_retain_n)(HeapObject *object, uint32_t n);
HeapObject *swift::swift_nonatomic_retain_n(HeapObject *object, uint32_t n) {
SWIFT_RT_TRACK_INVOCATION(object, swift_nonatomic_retain_n);
@@ -332,17 +343,20 @@ HeapObject *swift::swift_nonatomic_retain_n(HeapObject *object, uint32_t n) {
return object;
}
void swift::swift_release(HeapObject *object) {
_swift_release(object);
}
static void _swift_release_(HeapObject *object) {
SWIFT_RT_TRACK_INVOCATION(object, swift_release);
if (isValidPointerForNativeRetain(object))
object->refCounts.decrementAndMaybeDeinit(1);
}
auto swift::_swift_release = _swift_release_;
void swift::swift_release(HeapObject *object) {
if (SWIFT_UNLIKELY(_swift_release))
_swift_release(object);
else
_swift_release_(object);
}
void (*swift::_swift_release)(HeapObject *object);
void swift::swift_nonatomic_release(HeapObject *object) {
SWIFT_RT_TRACK_INVOCATION(object, swift_nonatomic_release);
@@ -350,17 +364,20 @@ void swift::swift_nonatomic_release(HeapObject *object) {
object->refCounts.decrementAndMaybeDeinitNonAtomic(1);
}
void swift::swift_release_n(HeapObject *object, uint32_t n) {
return _swift_release_n(object, n);
}
static void _swift_release_n_(HeapObject *object, uint32_t n) {
SWIFT_RT_TRACK_INVOCATION(object, swift_release_n);
if (isValidPointerForNativeRetain(object))
object->refCounts.decrementAndMaybeDeinit(n);
}
auto swift::_swift_release_n = _swift_release_n_;
void swift::swift_release_n(HeapObject *object, uint32_t n) {
if (SWIFT_UNLIKELY(_swift_release_n))
return _swift_release_n(object, n);
else
return _swift_release_n_(object, n);
}
void (*swift::_swift_release_n)(HeapObject *object, uint32_t n);
void swift::swift_nonatomic_release_n(HeapObject *object, uint32_t n) {
SWIFT_RT_TRACK_INVOCATION(object, swift_nonatomic_release_n);
@@ -484,10 +501,6 @@ void swift::swift_nonatomic_unownedRelease_n(HeapObject *object, int n) {
}
}
HeapObject *swift::swift_tryRetain(HeapObject *object) {
return _swift_tryRetain(object);
}
static HeapObject *_swift_tryRetain_(HeapObject *object) {
SWIFT_RT_TRACK_INVOCATION(object, swift_tryRetain);
if (!isValidPointerForNativeRetain(object))
@@ -497,7 +510,14 @@ static HeapObject *_swift_tryRetain_(HeapObject *object) {
else return nullptr;
}
auto swift::_swift_tryRetain = _swift_tryRetain_;
HeapObject *swift::swift_tryRetain(HeapObject *object) {
if (SWIFT_UNLIKELY(_swift_tryRetain))
return _swift_tryRetain(object);
else
return _swift_tryRetain_(object);
}
HeapObject *(*swift::_swift_tryRetain)(HeapObject *object);
bool swift::swift_isDeallocating(HeapObject *object) {
if (!isValidPointerForNativeRetain(object))