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

[Peter Collingbourne via llvm-branch-commits]

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@@ -905,6 +906,29 @@ bool ConstStructBuilder::Build(const APValue &Val, const RecordDecl *RD,
     if (!EltInit)
       return false;
 
+    if (CGM.getContext().isPFPField(*Field)) {
+      llvm::ConstantInt *Disc;
+      llvm::Constant *AddrDisc;
+      if (CGM.getContext().arePFPFieldsTriviallyCopyable(RD)) {
+        uint64_t FieldSignature =
+            llvm::getPointerAuthStableSipHash(CGM.getPFPFieldName(*Field));
+        Disc = llvm::ConstantInt::get(CGM.Int64Ty, FieldSignature);
+        AddrDisc = llvm::ConstantPointerNull::get(CGM.VoidPtrTy);
+      } else if (Emitter.isAbstract()) {
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pcc wrote:

`isAbstract` means that we don't know the global's address. Since we can only form a pointer without knowing the address if the fields are trivially copyable, I think this is the right place for the condition.

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