[clang] [clang][bytecode] Check that a ltor cast to a complex value is possible (PR #155152)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Timm Baeder (tbaederr)

<details>
<summary>Changes</summary>

When we get to this point, the pointer might _not_ be backed by a primitive array, so the later code will fail.

Fixes #<!-- -->155144

---
Full diff: https://github.com/llvm/llvm-project/pull/155152.diff


2 Files Affected:

- (modified) clang/lib/AST/ByteCode/Pointer.cpp (+4-1) 
- (modified) clang/test/AST/ByteCode/c.c (+4) 


``````````diff
diff --git a/clang/lib/AST/ByteCode/Pointer.cpp b/clang/lib/AST/ByteCode/Pointer.cpp
index 7dc6b0c6d437b..2f67c5e3e3479 100644
--- a/clang/lib/AST/ByteCode/Pointer.cpp
+++ b/clang/lib/AST/ByteCode/Pointer.cpp
@@ -785,8 +785,11 @@ std::optional<APValue> Pointer::toRValue(const Context &Ctx,
 
     // Complex types.
     if (const auto *CT = Ty->getAs<ComplexType>()) {
-      QualType ElemTy = CT->getElementType();
+      // Can happen via C casts.
+      if (!Ptr.getFieldDesc()->isPrimitiveArray())
+        return false;
 
+      QualType ElemTy = CT->getElementType();
       if (ElemTy->isIntegerType()) {
         OptPrimType ElemT = Ctx.classify(ElemTy);
         assert(ElemT);
diff --git a/clang/test/AST/ByteCode/c.c b/clang/test/AST/ByteCode/c.c
index 73469d7fd6cc4..eb46330c7d35f 100644
--- a/clang/test/AST/ByteCode/c.c
+++ b/clang/test/AST/ByteCode/c.c
@@ -173,6 +173,10 @@ _Static_assert(CTB3, ""); // pedantic-ref-warning {{GNU extension}} \
                           // pedantic-expected-warning {{GNU extension}}
 
 
+void nonComplexToComplexCast(void) {
+  _Complex double z = *(_Complex double *)&(struct { double r, i; }){0.0, 1.0};
+}
+
 int t1 = sizeof(int);
 void test4(void) {
   t1 = sizeof(int);

``````````

</details>


https://github.com/llvm/llvm-project/pull/155152