[clang] 156ab4d - [Clang][Sema] set declaration invalid earlier to prevent crash in calculating record layout (#87173)

[via cfe-commits]

Author: Qizhi Hu
Date: 2024-04-18T08:52:25+08:00
New Revision: 156ab4d4fb06be93b0cfce675e4cf86d330d879c

URL: https://github.com/llvm/llvm-project/commit/156ab4d4fb06be93b0cfce675e4cf86d330d879c
DIFF: https://github.com/llvm/llvm-project/commit/156ab4d4fb06be93b0cfce675e4cf86d330d879c.diff

LOG: [Clang][Sema] set declaration invalid earlier to prevent crash in calculating record layout (#87173)

Try to fix https://github.com/llvm/llvm-project/issues/75221
This crash caused by calculating record layout which contains a field
declaration with dependent type. Make it invalid before it is a complete
definition to prevent this crash. Define a new scope type to record this
type alias and set the record declaration invalid when it is defined in
a type alias template.

Co-authored-by: huqizhi <836744285 at qq.com>

Added: 
    clang/test/SemaCXX/PR75221.cpp

Modified: 
    clang/docs/ReleaseNotes.rst
    clang/include/clang/Sema/Scope.h
    clang/lib/Parse/ParseDeclCXX.cpp
    clang/lib/Sema/SemaDecl.cpp

Removed: 
    


################################################################################
diff  --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index c19ad9fba58f37..6c51c2d1f483ce 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -536,6 +536,8 @@ Bug Fixes to C++ Support
   Fixes (#GH70604), (#GH79754), (#GH84163), (#GH84425), (#GH86054), (#GH86398), and (#GH86399).
 - Fix a crash when deducing ``auto`` from an invalid dereference (#GH88329).
 - Fix a crash in requires expression with templated base class member function. Fixes (#GH84020).
+- Fix a crash caused by defined struct in a type alias template when the structure
+  has fields with dependent type. Fixes (#GH75221).
 
 Bug Fixes to AST Handling
 ^^^^^^^^^^^^^^^^^^^^^^^^^

diff  --git a/clang/include/clang/Sema/Scope.h b/clang/include/clang/Sema/Scope.h
index 099c2739e8603a..1752a25111a775 100644
--- a/clang/include/clang/Sema/Scope.h
+++ b/clang/include/clang/Sema/Scope.h
@@ -156,6 +156,9 @@ class Scope {
     /// This is the scope of an OpenACC Compute Construct, which restricts
     /// jumping into/out of it.
     OpenACCComputeConstructScope = 0x10000000,
+
+    /// This is a scope of type alias declaration.
+    TypeAliasScope = 0x20000000,
   };
 
 private:
@@ -580,6 +583,9 @@ class Scope {
   /// if/switch/while/for statement.
   bool isControlScope() const { return getFlags() & Scope::ControlScope; }
 
+  /// Determine whether this scope is a type alias scope.
+  bool isTypeAliasScope() const { return getFlags() & Scope::TypeAliasScope; }
+
   /// Returns if rhs has a higher scope depth than this.
   ///
   /// The caller is responsible for calling this only if one of the two scopes

diff  --git a/clang/lib/Parse/ParseDeclCXX.cpp b/clang/lib/Parse/ParseDeclCXX.cpp
index 51fd64b2d01aa7..8e0e8682482933 100644
--- a/clang/lib/Parse/ParseDeclCXX.cpp
+++ b/clang/lib/Parse/ParseDeclCXX.cpp
@@ -799,6 +799,11 @@ Parser::DeclGroupPtrTy Parser::ParseUsingDeclaration(
     ProhibitAttributes(PrefixAttrs);
 
     Decl *DeclFromDeclSpec = nullptr;
+    Scope *CurScope = getCurScope();
+    if (CurScope)
+      CurScope->setFlags(Scope::ScopeFlags::TypeAliasScope |
+                         CurScope->getFlags());
+
     Decl *AD = ParseAliasDeclarationAfterDeclarator(
         TemplateInfo, UsingLoc, D, DeclEnd, AS, Attrs, &DeclFromDeclSpec);
     return Actions.ConvertDeclToDeclGroup(AD, DeclFromDeclSpec);

diff  --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 1bde99d6fce740..356abe09a5ca62 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -19529,6 +19529,13 @@ void Sema::ActOnFields(Scope *S, SourceLocation RecLoc, Decl *EnclosingDecl,
   // Okay, we successfully defined 'Record'.
   if (Record) {
     bool Completed = false;
+    if (S) {
+      Scope *Parent = S->getParent();
+      if (Parent && Parent->isTypeAliasScope() &&
+          Parent->isTemplateParamScope())
+        Record->setInvalidDecl();
+    }
+
     if (CXXRecord) {
       if (!CXXRecord->isInvalidDecl()) {
         // Set access bits correctly on the directly-declared conversions.

diff  --git a/clang/test/SemaCXX/PR75221.cpp b/clang/test/SemaCXX/PR75221.cpp
new file mode 100644
index 00000000000000..b342e347c5606a
--- /dev/null
+++ b/clang/test/SemaCXX/PR75221.cpp
@@ -0,0 +1,6 @@
+// RUN: %clang_cc1 -verify -std=c++11 -fsyntax-only %s
+
+template <class T> using foo = struct foo { // expected-error {{'foo' cannot be defined in a type alias template}}
+  T size = 0;
+};
+foo a;