[clang] [clang][Sema] Add checks for validity of default ctor's class (PR #78898)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Vlad Serebrennikov (Endilll)

<details>
<summary>Changes</summary>

Fixes #<!-- -->10518
Fixes #<!-- -->67914
Fixes #<!-- -->78388
Also addresses the second example in #<!-- -->49103

This patch is based on suggestion from @<!-- -->cor3ntin in https://github.com/llvm/llvm-project/issues/67914#issuecomment-1896011898

---
Full diff: https://github.com/llvm/llvm-project/pull/78898.diff


2 Files Affected:

- (modified) clang/docs/ReleaseNotes.rst (+5) 
- (modified) clang/lib/Sema/SemaDeclCXX.cpp (+7) 


``````````diff
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 8bb26fcae18d6b..5971bda21a5e25 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -1013,6 +1013,11 @@ Bug Fixes to C++ Support
 - Fix a false-positive ODR violation for different definitions for `std::align_val_t`.
   Fixes (`#76638 <https://github.com/llvm/llvm-project/issues/76638>`_)
 
+- Fix crash when calling the constructor of an invalid class.
+  Fixes (`#10518 <https://github.com/llvm/llvm-project/issues/10518>`_),
+  (`#67914 <https://github.com/llvm/llvm-project/issues/10518>`_),
+  and (`#78388 <https://github.com/llvm/llvm-project/issues/78388>`_)
+
 - Remove recorded `#pragma once` state for headers included in named modules.
   Fixes (`#77995 <https://github.com/llvm/llvm-project/issues/77995>`_)
 
diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index df5bd55e7c2836..634af573480b45 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -5990,6 +5990,10 @@ void Sema::ActOnDefaultCtorInitializers(Decl *CDtorDecl) {
 
   if (CXXConstructorDecl *Constructor
       = dyn_cast<CXXConstructorDecl>(CDtorDecl)) {
+    if (CXXRecordDecl *ClassDecl = Constructor->getParent();
+        !ClassDecl || ClassDecl->isInvalidDecl()) {
+      return;
+    }
     SetCtorInitializers(Constructor, /*AnyErrors=*/false);
     DiagnoseUninitializedFields(*this, Constructor);
   }
@@ -14030,6 +14034,9 @@ void Sema::DefineImplicitDefaultConstructor(SourceLocation CurrentLocation,
 
   CXXRecordDecl *ClassDecl = Constructor->getParent();
   assert(ClassDecl && "DefineImplicitDefaultConstructor - invalid constructor");
+  if (ClassDecl->isInvalidDecl()) {
+    return;
+  }
 
   SynthesizedFunctionScope Scope(*this, Constructor);
 

``````````

</details>


https://github.com/llvm/llvm-project/pull/78898