[clang] [clang][Interp] Use array filler expression (PR #72865)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Timm Baeder (tbaederr)

<details>
<summary>Changes</summary>

This is obviously not what we should ideally do, but the current state is also broken. We are just leaving the other elements uninitialized and rely on them being zero-ed.

---
Full diff: https://github.com/llvm/llvm-project/pull/72865.diff


1 Files Affected:

- (modified) clang/lib/AST/Interp/ByteCodeExprGen.cpp (+14-1) 


``````````diff
diff --git a/clang/lib/AST/Interp/ByteCodeExprGen.cpp b/clang/lib/AST/Interp/ByteCodeExprGen.cpp
index 5dc1f9dfb10ff32..180749a75ebd22e 100644
--- a/clang/lib/AST/Interp/ByteCodeExprGen.cpp
+++ b/clang/lib/AST/Interp/ByteCodeExprGen.cpp
@@ -662,13 +662,26 @@ bool ByteCodeExprGen<Emitter>::VisitInitListExpr(const InitListExpr *E) {
     return this->visitInitList(E->inits(), E);
 
   if (T->isArrayType()) {
-    // FIXME: Array fillers.
     unsigned ElementIndex = 0;
     for (const Expr *Init : E->inits()) {
       if (!this->visitArrayElemInit(ElementIndex, Init))
         return false;
       ++ElementIndex;
     }
+
+    // Expand the filler expression.
+    // FIXME: This should go away.
+    if (const Expr *Filler = E->getArrayFiller()) {
+      const ConstantArrayType *CAT =
+          Ctx.getASTContext().getAsConstantArrayType(E->getType());
+      uint64_t NumElems = CAT->getSize().getZExtValue();
+
+      for (; ElementIndex != NumElems; ++ElementIndex) {
+        if (!this->visitArrayElemInit(ElementIndex, Filler))
+          return false;
+      }
+    }
+
     return true;
   }
 

``````````

</details>


https://github.com/llvm/llvm-project/pull/72865