[Clang] [NFC] Fix potential dereferencing of nullptr

[smanna12]

This patch replaces getAs with castAs and dyn_cast with cast to ensure type safety and prevents potential null pointer dereferences. These changes enforce compile-time checks for correct type casting in ASTContext and CodeGenModule.

[llvmbot]

@llvm/pr-subscribers-clang

@llvm/pr-subscribers-clang-codegen

Author: None (smanna12)

Changes

This patch replaces getAs<> with castAs<> and dyn_cast<> with cast<>.

---

Full diff: https://github.com/llvm/llvm-project/pull/101405.diff

2 Files Affected:

• (modified) clang/lib/AST/ASTContext.cpp (+2-2)
• (modified) clang/lib/CodeGen/CodeGenModule.cpp (+1-1)

diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
index a465cdfcf3c89..b0cc7cb826f97 100644
--- a/clang/lib/AST/ASTContext.cpp
+++ b/clang/lib/AST/ASTContext.cpp
@@ -3283,7 +3283,7 @@ static void encodeTypeForFunctionPointerAuth(const ASTContext &Ctx,
     return;
 
   case Type::Builtin: {
-    const auto *BTy = T->getAs<BuiltinType>();
+    const auto *BTy = T->castAs<BuiltinType>();
     switch (BTy->getKind()) {
 #define SIGNED_TYPE(Id, SingletonId)                                           \
   case BuiltinType::Id:                                                        \
@@ -3366,7 +3366,7 @@ static void encodeTypeForFunctionPointerAuth(const ASTContext &Ctx,
     llvm_unreachable("should never get here");
   }
   case Type::Record: {
-    const RecordDecl *RD = T->getAs<RecordType>()->getDecl();
+    const RecordDecl *RD = T->castAs<RecordType>()->getDecl();
     const IdentifierInfo *II = RD->getIdentifier();
 
     // In C++, an immediate typedef of an anonymous struct or union
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 344a0e538f22a..760185d4d51ff 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -5659,7 +5659,7 @@ void CodeGenModule::EmitExternalFunctionDeclaration(const FunctionDecl *FD) {
     if (getCodeGenOpts().hasReducedDebugInfo()) {
       auto *Ty = getTypes().ConvertType(FD->getType());
       StringRef MangledName = getMangledName(FD);
-      auto *Fn = dyn_cast<llvm::Function>(
+      auto *Fn = cast<llvm::Function>(
           GetOrCreateLLVMFunction(MangledName, Ty, FD, /* ForVTable */ false));
       if (!Fn->getSubprogram())
         DI->EmitFunctionDecl(FD, FD->getLocation(), FD->getType(), Fn);

[tahonermann]

Looks good! Thanks @smanna12!

[smanna12]

Thanks @tahonermann for reviews!