[clang] 6e0c441 - [NFC][CLANG] Fix nullptr dereference found by Coverity static analysis tool

[via cfe-commits]

Author: Manna, Soumi
Date: 2023-05-05T11:57:33-07:00
New Revision: 6e0c44174823260fd74d14d036eaf1c64fa5eded

URL: https://github.com/llvm/llvm-project/commit/6e0c44174823260fd74d14d036eaf1c64fa5eded
DIFF: https://github.com/llvm/llvm-project/commit/6e0c44174823260fd74d14d036eaf1c64fa5eded.diff

LOG: [NFC][CLANG] Fix nullptr dereference found by Coverity static analysis tool

Reported by Coverity:

  In clang::ASTContext::hasUniqueObjectRepresentations(clang::QualType, bool): Return value of function which returns null is dereferenced without checking.

  (Ty->isMemberPointerType()) {
      	//returned_null: getAs returns nullptr.
      	//var_assigned: Assigning: MPT = nullptr return value from getAs.
      const auto *MPT = Ty->getAs<MemberPointerType>();

     //dereference: Dereferencing a pointer that might be nullptr MPT when calling getMemberPointerInfo. (The virtual call resolves to
     <unnamed>::ItaniumCXXABI::getMemberPointerInfo.)
      return !ABI->getMemberPointerInfo(MPT).HasPadding;
    }

ABIs assume the parameter passed to `getMemberPointerInfo` is non-null.
This patch checks type by doing a `if (const auto *MPT = Ty->getAs<MemberPointerType>())` instead.

Reviewed By: erichkeane

Differential Revision: https://reviews.llvm.org/D149922

Added: 
    

Modified: 
    clang/lib/AST/ASTContext.cpp

Removed: 
    


################################################################################
diff  --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
index 3a72c3d25794..de65c3cc47b9 100644
--- a/clang/lib/AST/ASTContext.cpp
+++ b/clang/lib/AST/ASTContext.cpp
@@ -2859,10 +2859,8 @@ bool ASTContext::hasUniqueObjectRepresentations(
   if (Ty->isPointerType())
     return true;
 
-  if (Ty->isMemberPointerType()) {
-    const auto *MPT = Ty->getAs<MemberPointerType>();
+  if (const auto *MPT = Ty->getAs<MemberPointerType>())
     return !ABI->getMemberPointerInfo(MPT).HasPadding;
-  }
 
   if (Ty->isRecordType()) {
     const RecordDecl *Record = Ty->castAs<RecordType>()->getDecl();