[clang] [Clang] Fix dependence handling of nttp for variable templates (PR #69075)

via cfe-commits cfe-commits at lists.llvm.org
Mon Oct 16 09:00:15 PDT 2023


https://github.com/LYP951018 updated https://github.com/llvm/llvm-project/pull/69075

>From e7c7969f69755cff939c88f52987fedcb1ffcd76 Mon Sep 17 00:00:00 2001
From: letrec <liuyupei951018 at hotmail.com>
Date: Sun, 8 Oct 2023 00:44:11 +0800
Subject: [PATCH 1/2] Fix dependence handling for variable templates

---
 clang/include/clang/AST/ExprCXX.h          |  8 ++++++--
 clang/lib/AST/ASTImporter.cpp              |  5 ++++-
 clang/lib/AST/ExprCXX.cpp                  | 16 ++++++++--------
 clang/lib/Sema/SemaDeclCXX.cpp             |  5 +++--
 clang/lib/Sema/SemaTemplate.cpp            | 14 ++++++--------
 clang/test/SemaTemplate/dependent-expr.cpp | 15 +++++++++++++++
 6 files changed, 42 insertions(+), 21 deletions(-)

diff --git a/clang/include/clang/AST/ExprCXX.h b/clang/include/clang/AST/ExprCXX.h
index 17dbb5e888ebdd3..798c98cfcf2d4db 100644
--- a/clang/include/clang/AST/ExprCXX.h
+++ b/clang/include/clang/AST/ExprCXX.h
@@ -3191,7 +3191,8 @@ class UnresolvedLookupExpr final
                        const DeclarationNameInfo &NameInfo, bool RequiresADL,
                        bool Overloaded,
                        const TemplateArgumentListInfo *TemplateArgs,
-                       UnresolvedSetIterator Begin, UnresolvedSetIterator End);
+                       UnresolvedSetIterator Begin, UnresolvedSetIterator End,
+                       bool KnownDependent);
 
   UnresolvedLookupExpr(EmptyShell Empty, unsigned NumResults,
                        bool HasTemplateKWAndArgsInfo);
@@ -3211,12 +3212,15 @@ class UnresolvedLookupExpr final
          const DeclarationNameInfo &NameInfo, bool RequiresADL, bool Overloaded,
          UnresolvedSetIterator Begin, UnresolvedSetIterator End);
 
+  // After canonicalization, there may be dependent template arguments in
+  // CanonicalConverted But none of Args is dependent. When any of
+  // CanonicalConverted dependent, KnownDependent is true.
   static UnresolvedLookupExpr *
   Create(const ASTContext &Context, CXXRecordDecl *NamingClass,
          NestedNameSpecifierLoc QualifierLoc, SourceLocation TemplateKWLoc,
          const DeclarationNameInfo &NameInfo, bool RequiresADL,
          const TemplateArgumentListInfo *Args, UnresolvedSetIterator Begin,
-         UnresolvedSetIterator End);
+         UnresolvedSetIterator End, bool KnownDependent);
 
   static UnresolvedLookupExpr *CreateEmpty(const ASTContext &Context,
                                            unsigned NumResults,
diff --git a/clang/lib/AST/ASTImporter.cpp b/clang/lib/AST/ASTImporter.cpp
index 3adbabdb7fb878a..a9a841f28a4bf92 100644
--- a/clang/lib/AST/ASTImporter.cpp
+++ b/clang/lib/AST/ASTImporter.cpp
@@ -8394,10 +8394,13 @@ ASTNodeImporter::VisitUnresolvedLookupExpr(UnresolvedLookupExpr *E) {
     if (!ToTemplateKeywordLocOrErr)
       return ToTemplateKeywordLocOrErr.takeError();
 
+    const bool KnownDependent =
+        (E->getDependence() & ExprDependence::TypeValue) ==
+        ExprDependence::TypeValue;
     return UnresolvedLookupExpr::Create(
         Importer.getToContext(), *ToNamingClassOrErr, *ToQualifierLocOrErr,
         *ToTemplateKeywordLocOrErr, ToNameInfo, E->requiresADL(), &ToTAInfo,
-        ToDecls.begin(), ToDecls.end());
+        ToDecls.begin(), ToDecls.end(), KnownDependent);
   }
 
   return UnresolvedLookupExpr::Create(
diff --git a/clang/lib/AST/ExprCXX.cpp b/clang/lib/AST/ExprCXX.cpp
index 06163255f9b5e54..5fbfa3a78124653 100644
--- a/clang/lib/AST/ExprCXX.cpp
+++ b/clang/lib/AST/ExprCXX.cpp
@@ -354,10 +354,10 @@ UnresolvedLookupExpr::UnresolvedLookupExpr(
     NestedNameSpecifierLoc QualifierLoc, SourceLocation TemplateKWLoc,
     const DeclarationNameInfo &NameInfo, bool RequiresADL, bool Overloaded,
     const TemplateArgumentListInfo *TemplateArgs, UnresolvedSetIterator Begin,
-    UnresolvedSetIterator End)
+    UnresolvedSetIterator End, bool KnownDependent)
     : OverloadExpr(UnresolvedLookupExprClass, Context, QualifierLoc,
-                   TemplateKWLoc, NameInfo, TemplateArgs, Begin, End, false,
-                   false, false),
+                   TemplateKWLoc, NameInfo, TemplateArgs, Begin, End,
+                   KnownDependent, false, false),
       NamingClass(NamingClass) {
   UnresolvedLookupExprBits.RequiresADL = RequiresADL;
   UnresolvedLookupExprBits.Overloaded = Overloaded;
@@ -380,7 +380,7 @@ UnresolvedLookupExpr *UnresolvedLookupExpr::Create(
   void *Mem = Context.Allocate(Size, alignof(UnresolvedLookupExpr));
   return new (Mem) UnresolvedLookupExpr(Context, NamingClass, QualifierLoc,
                                         SourceLocation(), NameInfo, RequiresADL,
-                                        Overloaded, nullptr, Begin, End);
+                                        Overloaded, nullptr, Begin, End, false);
 }
 
 UnresolvedLookupExpr *UnresolvedLookupExpr::Create(
@@ -388,7 +388,7 @@ UnresolvedLookupExpr *UnresolvedLookupExpr::Create(
     NestedNameSpecifierLoc QualifierLoc, SourceLocation TemplateKWLoc,
     const DeclarationNameInfo &NameInfo, bool RequiresADL,
     const TemplateArgumentListInfo *Args, UnresolvedSetIterator Begin,
-    UnresolvedSetIterator End) {
+    UnresolvedSetIterator End, bool KnownDependent) {
   assert(Args || TemplateKWLoc.isValid());
   unsigned NumResults = End - Begin;
   unsigned NumTemplateArgs = Args ? Args->size() : 0;
@@ -396,9 +396,9 @@ UnresolvedLookupExpr *UnresolvedLookupExpr::Create(
       totalSizeToAlloc<DeclAccessPair, ASTTemplateKWAndArgsInfo,
                        TemplateArgumentLoc>(NumResults, 1, NumTemplateArgs);
   void *Mem = Context.Allocate(Size, alignof(UnresolvedLookupExpr));
-  return new (Mem) UnresolvedLookupExpr(Context, NamingClass, QualifierLoc,
-                                        TemplateKWLoc, NameInfo, RequiresADL,
-                                        /*Overloaded*/ true, Args, Begin, End);
+  return new (Mem) UnresolvedLookupExpr(
+      Context, NamingClass, QualifierLoc, TemplateKWLoc, NameInfo, RequiresADL,
+      /*Overloaded*/ true, Args, Begin, End, KnownDependent);
 }
 
 UnresolvedLookupExpr *UnresolvedLookupExpr::CreateEmpty(
diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index f9c010b1a002488..f607d6c0bb1bb4a 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -1299,8 +1299,9 @@ static bool checkTupleLikeDecomposition(Sema &S,
       //   in the associated namespaces.
       Expr *Get = UnresolvedLookupExpr::Create(
           S.Context, nullptr, NestedNameSpecifierLoc(), SourceLocation(),
-          DeclarationNameInfo(GetDN, Loc), /*RequiresADL*/true, &Args,
-          UnresolvedSetIterator(), UnresolvedSetIterator());
+          DeclarationNameInfo(GetDN, Loc), /*RequiresADL*/ true, &Args,
+          UnresolvedSetIterator(), UnresolvedSetIterator(),
+          /*KnownDependent*/ false);
 
       Expr *Arg = E.get();
       E = S.BuildCallExpr(nullptr, Get, Loc, Arg, Loc);
diff --git a/clang/lib/Sema/SemaTemplate.cpp b/clang/lib/Sema/SemaTemplate.cpp
index ff370dd1e080b2b..6389ec708bf34ae 100644
--- a/clang/lib/Sema/SemaTemplate.cpp
+++ b/clang/lib/Sema/SemaTemplate.cpp
@@ -4982,7 +4982,7 @@ ExprResult Sema::BuildTemplateIdExpr(const CXXScopeSpec &SS,
       return ExprError();
     }
   }
-
+  bool KnownDependent = false;
   // In C++1y, check variable template ids.
   if (R.getAsSingle<VarTemplateDecl>()) {
     ExprResult Res = CheckVarTemplateId(SS, R.getLookupNameInfo(),
@@ -4991,6 +4991,7 @@ ExprResult Sema::BuildTemplateIdExpr(const CXXScopeSpec &SS,
     if (Res.isInvalid() || Res.isUsable())
       return Res;
     // Result is dependent. Carry on to build an UnresolvedLookupEpxr.
+    KnownDependent = true;
   }
 
   if (R.getAsSingle<ConceptDecl>()) {
@@ -5002,13 +5003,10 @@ ExprResult Sema::BuildTemplateIdExpr(const CXXScopeSpec &SS,
   // We don't want lookup warnings at this point.
   R.suppressDiagnostics();
 
-  UnresolvedLookupExpr *ULE
-    = UnresolvedLookupExpr::Create(Context, R.getNamingClass(),
-                                   SS.getWithLocInContext(Context),
-                                   TemplateKWLoc,
-                                   R.getLookupNameInfo(),
-                                   RequiresADL, TemplateArgs,
-                                   R.begin(), R.end());
+  UnresolvedLookupExpr *ULE = UnresolvedLookupExpr::Create(
+      Context, R.getNamingClass(), SS.getWithLocInContext(Context),
+      TemplateKWLoc, R.getLookupNameInfo(), RequiresADL, TemplateArgs,
+      R.begin(), R.end(), KnownDependent);
 
   return ULE;
 }
diff --git a/clang/test/SemaTemplate/dependent-expr.cpp b/clang/test/SemaTemplate/dependent-expr.cpp
index 51bd375d7920eed..26a7984ccb2c268 100644
--- a/clang/test/SemaTemplate/dependent-expr.cpp
+++ b/clang/test/SemaTemplate/dependent-expr.cpp
@@ -165,3 +165,18 @@ namespace BindingInStmtExpr {
   using U = decltype(num_bindings<T>()); // expected-note {{previous}}
   using U = N<3>; // expected-error-re {{type alias redefinition with different types ('N<3>' vs {{.*}}N<2>}}
 }
+
+namespace PR65153 {
+struct A{};
+
+template <const A& T>
+const A JoinStringViews = T;
+
+template <int V>
+class Builder {
+public:
+    static constexpr A Equal{};
+    // no crash here
+    static constexpr auto Val = JoinStringViews<Equal>;
+};
+} // namespace PR65153
\ No newline at end of file

>From 443851fc30b9b042d8f7280497b20a353ab58a3e Mon Sep 17 00:00:00 2001
From: letrec <liuyupei951018 at hotmail.com>
Date: Mon, 16 Oct 2023 23:59:54 +0800
Subject: [PATCH 2/2] fix CR comments

---
 clang/docs/ReleaseNotes.rst                | 4 ++++
 clang/lib/Sema/SemaDeclCXX.cpp             | 2 +-
 clang/test/SemaTemplate/dependent-expr.cpp | 2 +-
 3 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index be7c8bf247f7af5..698028df09eb162 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -509,6 +509,10 @@ Bug Fixes to C++ Support
   rather than prefer the non-templated constructor as specified in
   [standard.group]p3.
 
+- Fixed a crash caused by incorrect handling of dependence on variable templates 
+  with non-type template parameters of reference type. Fixes:
+  (`#65153 <https://github.com/llvm/llvm-project/issues/65153>`_)
+
 Bug Fixes to AST Handling
 ^^^^^^^^^^^^^^^^^^^^^^^^^
 - Fixed an import failure of recursive friend class template.
diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index f607d6c0bb1bb4a..0193e476b3a781b 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -1301,7 +1301,7 @@ static bool checkTupleLikeDecomposition(Sema &S,
           S.Context, nullptr, NestedNameSpecifierLoc(), SourceLocation(),
           DeclarationNameInfo(GetDN, Loc), /*RequiresADL*/ true, &Args,
           UnresolvedSetIterator(), UnresolvedSetIterator(),
-          /*KnownDependent*/ false);
+          /*KnownDependent=*/false);
 
       Expr *Arg = E.get();
       E = S.BuildCallExpr(nullptr, Get, Loc, Arg, Loc);
diff --git a/clang/test/SemaTemplate/dependent-expr.cpp b/clang/test/SemaTemplate/dependent-expr.cpp
index 26a7984ccb2c268..ce210d9b74f6d98 100644
--- a/clang/test/SemaTemplate/dependent-expr.cpp
+++ b/clang/test/SemaTemplate/dependent-expr.cpp
@@ -179,4 +179,4 @@ class Builder {
     // no crash here
     static constexpr auto Val = JoinStringViews<Equal>;
 };
-} // namespace PR65153
\ No newline at end of file
+} // namespace PR65153



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