[clang] [clang][analysis]Use dyn_cast_or_null instead cast to prevent crash (PR #68510)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang-analysis

<details>
<summary>Changes</summary>

`getStorageLocation` may return `nullptr` and this will produce crash when use `cast`, use `dyn_cast_or_null` instead. I test it locally using [FTXUI](https://github.com/ArthurSonzogni/FTXUI) and it may be the cause of issue [issue](https://github.com/llvm/llvm-project/issues/68412), but I am not sure.

---
Full diff: https://github.com/llvm/llvm-project/pull/68510.diff


1 Files Affected:

- (modified) clang/lib/Analysis/FlowSensitive/Models/UncheckedOptionalAccessModel.cpp (+2-1) 


``````````diff
diff --git a/clang/lib/Analysis/FlowSensitive/Models/UncheckedOptionalAccessModel.cpp b/clang/lib/Analysis/FlowSensitive/Models/UncheckedOptionalAccessModel.cpp
index f61f26ff27804ec..dda1c6cfca017d0 100644
--- a/clang/lib/Analysis/FlowSensitive/Models/UncheckedOptionalAccessModel.cpp
+++ b/clang/lib/Analysis/FlowSensitive/Models/UncheckedOptionalAccessModel.cpp
@@ -26,6 +26,7 @@
 #include "clang/Analysis/FlowSensitive/NoopLattice.h"
 #include "clang/Analysis/FlowSensitive/StorageLocation.h"
 #include "clang/Analysis/FlowSensitive/Value.h"
+#include "clang/Basic/LLVM.h"
 #include "clang/Basic/SourceLocation.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/Casting.h"
@@ -599,7 +600,7 @@ void transferAssignment(const CXXOperatorCallExpr *E, BoolValue &HasValueVal,
                         LatticeTransferState &State) {
   assert(E->getNumArgs() > 0);
 
-  if (auto *Loc = cast<RecordStorageLocation>(
+  if (auto *Loc = dyn_cast_or_null<RecordStorageLocation>(
           State.Env.getStorageLocation(*E->getArg(0)))) {
     createOptionalValue(*Loc, HasValueVal, State.Env);
 

``````````

</details>


https://github.com/llvm/llvm-project/pull/68510