[clang] [clang][bytecode] Reject composite copies on primitive pointers (PR #180683)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Timm Baeder (tbaederr)

<details>
<summary>Changes</summary>

This should fail.

---
Full diff: https://github.com/llvm/llvm-project/pull/180683.diff


2 Files Affected:

- (modified) clang/lib/AST/ByteCode/InterpBuiltin.cpp (+5) 
- (modified) clang/test/AST/ByteCode/complex.cpp (+9) 


``````````diff
diff --git a/clang/lib/AST/ByteCode/InterpBuiltin.cpp b/clang/lib/AST/ByteCode/InterpBuiltin.cpp
index e47fc43ee8638..3db76c7ad4b41 100644
--- a/clang/lib/AST/ByteCode/InterpBuiltin.cpp
+++ b/clang/lib/AST/ByteCode/InterpBuiltin.cpp
@@ -6110,6 +6110,11 @@ static bool copyComposite(InterpState &S, CodePtr OpPC, const Pointer &Src,
 }
 
 bool DoMemcpy(InterpState &S, CodePtr OpPC, const Pointer &Src, Pointer &Dest) {
+  if (!Src.isBlockPointer() || Src.getFieldDesc()->isPrimitive())
+    return false;
+  if (!Dest.isBlockPointer() || Dest.getFieldDesc()->isPrimitive())
+    return false;
+
   return copyComposite(S, OpPC, Src, Dest);
 }
 
diff --git a/clang/test/AST/ByteCode/complex.cpp b/clang/test/AST/ByteCode/complex.cpp
index 4440f201bb059..8ae0e63886727 100644
--- a/clang/test/AST/ByteCode/complex.cpp
+++ b/clang/test/AST/ByteCode/complex.cpp
@@ -460,3 +460,12 @@ namespace Discard {
   }
   static_assert(test_side_effect() == 1);
 }
+
+namespace MemcpyOp {
+  const double x = 0.;
+
+  void foo() {
+    _Complex double z;
+    z = *(_Complex double *)&x;
+  };
+}

``````````

</details>


https://github.com/llvm/llvm-project/pull/180683