[llvm-branch-commits] [clang] [Clang] Add pointer field protection feature. (PR #172119)

[Peter Collingbourne via llvm-branch-commits]

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@@ -5627,15 +5754,25 @@ RValue CodeGenFunction::EmitCall(const CGFunctionInfo &CallInfo,
         } else {
           uint64_t SrcSize = SrcTypeSize.getFixedValue();
           uint64_t DstSize = DstTypeSize.getFixedValue();
+          bool HasPFPFields = !findPFPCoercedFields(*this, I->Ty).empty();
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pcc wrote:

This needs to be the same as the condition where `CreatePFPCoercedLoad` would return non-null; `!findPFPCoercedFields().empty()` has a different value than `hasPFPFields()` because the former checks `IsWithinUnion`.

`IsWithinUnion` was added to support trivial relocation. If we're removing the trivial relocation support, I think we might be able to remove `IsWithinUnion` and have `findPFPFields` not return fields within unions. Then everything will be calling `hasPFPFields` or `findPFPFields`.

https://github.com/llvm/llvm-project/pull/172119