[PATCH] D117285: [msan] Copy origin of byval arguments

[Vitaly Buka via Phabricator via llvm-commits]

vitalybuka requested review of this revision.
vitalybuka added inline comments.


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Comment at: llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp:1741
+                    getOriginPtrForArgument(&FArg, EntryIRB, ArgOffset);
+                EntryIRB.CreateMemCpy(CpOriginPtr, CopyAlign, OriginPtr,
+                                      CopyAlign, Size);
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eugenis wrote:
> This can get weird if the byval pointer is less than 4 byte aligned, but the alternatives are not pretty, either.
> 
> Also, you can bump the alignment `std::max(CopyAlign, kMinOriginAlignment)`.
Not sure if OriginPtr can be aligned higher then kMinOriginAlignment, as origin_tls base is 4 bytes aligned.
CpOriginPtr can be aligned higher, but I guess it does not matter here.

Also please notice the I changed copy size.


Repository:
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  https://reviews.llvm.org/D117285/new/

https://reviews.llvm.org/D117285