[clang] 15f0491 - [NFC] Fix a mem-sanitizer found issue in AutoType

[Erich Keane via cfe-commits]

Author: Erich Keane
Date: 2023-04-28T10:09:26-07:00
New Revision: 15f0491d3963d91202aef659acc20f59aa83fae7

URL: https://github.com/llvm/llvm-project/commit/15f0491d3963d91202aef659acc20f59aa83fae7
DIFF: https://github.com/llvm/llvm-project/commit/15f0491d3963d91202aef659acc20f59aa83fae7.diff

LOG: [NFC] Fix a mem-sanitizer found issue in AutoType

We only need the list of constriant template arguments when we have a
valid constraint.  We give up on merging the auto-type constraints if
the template arguments don't match, but neglected to clear the
collection of template arguments.  The result was we had an AutoType
where we initialized the number of template arguments, but never
initialized the template arguments themselves.

This patch adds an assert to catch this in the future, plus ensures we
clear out the vector so we don't try to create the AutoType incorrectly.

Added: 
    

Modified: 
    clang/lib/AST/ASTContext.cpp
    clang/lib/AST/Type.cpp

Removed: 
    


################################################################################
diff  --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
index e331df86235b2..6bc202ecd5b02 100644
--- a/clang/lib/AST/ASTContext.cpp
+++ b/clang/lib/AST/ASTContext.cpp
@@ -12982,8 +12982,10 @@ static QualType getCommonSugarTypeNode(ASTContext &Ctx, const Type *X,
     SmallVector<TemplateArgument, 8> As;
     if (CD &&
         getCommonTemplateArguments(Ctx, As, AX->getTypeConstraintArguments(),
-                                   AY->getTypeConstraintArguments()))
+                                   AY->getTypeConstraintArguments())) {
       CD = nullptr; // The arguments 
diff er, so make it unconstrained.
+      As.clear();
+    }
 
     // Both auto types can't be dependent, otherwise they wouldn't have been
     // sugar. This implies they can't contain unexpanded packs either.

diff  --git a/clang/lib/AST/Type.cpp b/clang/lib/AST/Type.cpp
index e1686a7c69d52..c0d225034be89 100644
--- a/clang/lib/AST/Type.cpp
+++ b/clang/lib/AST/Type.cpp
@@ -4630,6 +4630,7 @@ AutoType::AutoType(QualType DeducedAsType, AutoTypeKeyword Keyword,
   AutoTypeBits.Keyword = (unsigned)Keyword;
   AutoTypeBits.NumArgs = TypeConstraintArgs.size();
   this->TypeConstraintConcept = TypeConstraintConcept;
+  assert(TypeConstraintConcept || AutoTypeBits.NumArgs == 0);
   if (TypeConstraintConcept) {
     auto *ArgBuffer =
         const_cast<TemplateArgument *>(getTypeConstraintArguments().data());