UBSan: Fix unaligned load/stores found by Undefined Behaviour Sanitizer. #2522
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| @@ -501,7 +501,7 @@ static void _flattenPlist(CFPropertyListRef plist, CFMutableArrayRef objlist, CF | |||
| CFDictionaryAddValue(objtable, plist, (const void *)(uintptr_t)refnum); | |||
| if (_kCFRuntimeIDCFDictionary == type) { | |||
| CFIndex count = CFDictionaryGetCount((CFDictionaryRef)plist); | |||
| STACK_BUFFER_DECL(CFPropertyListRef, buffer, count <= 128 ? count * 2 : 1); | |||
| STACK_BUFFER_DECL(CFPropertyListRef, buffer, (count > 0 && count <= 128) ? count * 2 : 1); | |||
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Does this same check need to be repeated on the next line?
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It shouldn't be needed because if count == 0 then the stack allocation is used instead of the malloc()'d buffer. 1 byte is wasted on the stack but this is also the case if count > 128 and the heap is used instead of the stack.
| #endif | ||
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| /* Read bytes until the buffer is aligned. */ | ||
| while( ( (uintptr_t)bytes & align_mask ) && len > 0) { |
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Style nit; let's make it match the rest of the file
- Add unaligned_load32() / unaligned_store32() and
unaligned_load{16,32,64}be() that load/store using byte access. On
supported architectures clang should convert these into single
load / store instructions.
- When allocating buffers on the stack using STACK_BUFFER_DECL() ensure
the length is > 0, as VLA (Variable Length Arrays) cannot be 0 length.
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Seems reasonable to me; I'd like to get a second pair of eyes on here (@millenomi perhaps).
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@millenomi @phausler would you be able to have a look over this if you have some time? |
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@swift-ci test and merge |
Add unaligned_load32() / unaligned_store32() and
unaligned_load{16,32,64}be() that load/store using byte access. On
supported architectures clang should convert these into single
load / store instructions.
When allocating buffers on the stack using STACK_BUFFER_DECL() ensure
the length is > 0, as VLA (Variable Length Arrays) cannot be 0 length.