https://github.com/ChipsSpectre created
https://github.com/llvm/llvm-project/pull/78840
…a nullptr casted to an array of non-constant size to a reference (#76634).
This situation is undefined behavior, and should not lead to a compiler crash.
Thus, the problematic cast is only executed on non-null pointers.
Fixes one reason for a crash in #76634.
>From 2503669a55f8dae534440a4eacb66a4500f78e3f Mon Sep 17 00:00:00 2001
From: ChipsSpectre <maximilian.horn...@tum.de>
Date: Sat, 20 Jan 2024 11:26:32 +0100
Subject: [PATCH] [Clang][Parser] Fix crash of clang when trying to convert a
cast to a nullptr casted to an array of non-constant size to a reference
(#76634).
This situation is undefined behavior, and should not lead to a compiler crash.
Thus, the problematic cast is only executed on non-null pointers.
Fixes one reason for a crash in #76634.
---
clang/lib/AST/ExprConstant.cpp | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index f1d07d022b25848..165046bd06e92a9 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -9272,10 +9272,17 @@ bool PointerExprEvaluator::VisitCastExpr(const CastExpr
*E) {
}
// The result is a pointer to the first element of the array.
auto *AT = Info.Ctx.getAsArrayType(SubExpr->getType());
- if (auto *CAT = dyn_cast<ConstantArrayType>(AT))
+ if (auto *CAT = dyn_cast<ConstantArrayType>(AT)) {
Result.addArray(Info, E, CAT);
- else
- Result.addUnsizedArray(Info, E, AT->getElementType());
+ }
+ else {
+ if (Result.checkNullPointer(Info, E, CSK_ArrayToPointer)) {
+ // Only add unsized array if there actually is a pointer.
+ return false;
+ } else {
+ Result.addUnsizedArray(Info, E, AT->getElementType());
+ }
+ }
return true;
}
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