Title: [276501] branches/safari-611-branch/Source/WebKit
- Revision
- 276501
- Author
- [email protected]
- Date
- 2021-04-23 09:53:23 -0700 (Fri, 23 Apr 2021)
Log Message
Cherry-pick r276482. rdar://problem/77074513
[Mac] CMBaseClass object pointers can become unaligned on x86
https://bugs.webkit.org/show_bug.cgi?id=224950
<rdar://77020922>
Reviewed by Eric Carlson.
CMBaseClass has a 4-byte version member before its 8-byte pointers on x86. Deal with this
the same way we do with other pointer-bearing, static, CM-type objects: enforce a 4-byte
packing, and prepend the struct with another 4-byte object in order to force the pointers
into 8-byte alignment.
* Shared/mac/MediaFormatReader/CoreMediaWrapped.h:
(WebKit::CoreMediaWrapped<Wrapped>::vTable):
git-svn-id: https://svn.webkit.org/repository/webkit/trunk@276482 268f45cc-cd09-0410-ab3c-d52691b4dbfc
Modified Paths
Diff
Modified: branches/safari-611-branch/Source/WebKit/ChangeLog (276500 => 276501)
--- branches/safari-611-branch/Source/WebKit/ChangeLog 2021-04-23 16:31:30 UTC (rev 276500)
+++ branches/safari-611-branch/Source/WebKit/ChangeLog 2021-04-23 16:53:23 UTC (rev 276501)
@@ -1,3 +1,40 @@
+2021-04-23 Russell Epstein <[email protected]>
+
+ Cherry-pick r276482. rdar://problem/77074513
+
+ [Mac] CMBaseClass object pointers can become unaligned on x86
+ https://bugs.webkit.org/show_bug.cgi?id=224950
+ <rdar://77020922>
+
+ Reviewed by Eric Carlson.
+
+ CMBaseClass has a 4-byte version member before its 8-byte pointers on x86. Deal with this
+ the same way we do with other pointer-bearing, static, CM-type objects: enforce a 4-byte
+ packing, and prepend the struct with another 4-byte object in order to force the pointers
+ into 8-byte alignment.
+
+ * Shared/mac/MediaFormatReader/CoreMediaWrapped.h:
+ (WebKit::CoreMediaWrapped<Wrapped>::vTable):
+
+
+ git-svn-id: https://svn.webkit.org/repository/webkit/trunk@276482 268f45cc-cd09-0410-ab3c-d52691b4dbfc
+
+ 2021-04-22 Jer Noble <[email protected]>
+
+ [Mac] CMBaseClass object pointers can become unaligned on x86
+ https://bugs.webkit.org/show_bug.cgi?id=224950
+ <rdar://77020922>
+
+ Reviewed by Eric Carlson.
+
+ CMBaseClass has a 4-byte version member before its 8-byte pointers on x86. Deal with this
+ the same way we do with other pointer-bearing, static, CM-type objects: enforce a 4-byte
+ packing, and prepend the struct with another 4-byte object in order to force the pointers
+ into 8-byte alignment.
+
+ * Shared/mac/MediaFormatReader/CoreMediaWrapped.h:
+ (WebKit::CoreMediaWrapped<Wrapped>::vTable):
+
2021-04-21 Alan Coon <[email protected]>
Cherry-pick r275805. rdar://problem/76963040
Modified: branches/safari-611-branch/Source/WebKit/Shared/mac/MediaFormatReader/CoreMediaWrapped.h (276500 => 276501)
--- branches/safari-611-branch/Source/WebKit/Shared/mac/MediaFormatReader/CoreMediaWrapped.h 2021-04-23 16:31:30 UTC (rev 276500)
+++ branches/safari-611-branch/Source/WebKit/Shared/mac/MediaFormatReader/CoreMediaWrapped.h 2021-04-23 16:53:23 UTC (rev 276501)
@@ -142,12 +142,23 @@
template<typename Wrapped>
const typename CoreMediaWrapped<Wrapped>::WrapperVTable& CoreMediaWrapped<Wrapped>::vTable()
{
- static constexpr CMBaseClass baseClass = wrapperClass<sizeof(Wrapped)>();
- static constexpr WrapperClass derivedClass = Wrapped::wrapperClass();
+ // CMBaseClass contains 64-bit pointers that aren't 8-byte aligned. To suppress the linker
+ // warning about this, we prepend 4 bytes of padding when building.
+#if CPU(X86_64)
+ constexpr size_t padSize = 4;
+#else
+ constexpr size_t padSize = 0;
+#endif
+
+#pragma pack(push, 4)
+ static constexpr struct { uint8_t pad[padSize]; CMBaseClass baseClass; } baseClass { { }, wrapperClass<sizeof(Wrapped)>() };
+ static constexpr struct { uint8_t pad[padSize]; WrapperClass derivedClass; } derivedClass { { }, Wrapped::wrapperClass() };
+#pragma pack(pop)
+
IGNORE_WARNINGS_BEGIN("missing-field-initializers")
static constexpr WrapperVTable vTable {
- { nullptr, &baseClass },
- &derivedClass,
+ { nullptr, &baseClass.baseClass },
+ &derivedClass.derivedClass,
};
IGNORE_WARNINGS_END
return vTable;
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