[llvm-branch-commits] [clang] 8ac7095 - [SemaTemplate] Stop passing insertion position around during VarTemplate instantiation

[Tom Stellard via llvm-branch-commits]

Author: Bruno Cardoso Lopes
Date: 2020-11-24T23:25:38-05:00
New Revision: 8ac709578067f77a7036fe50610277516fa36d50

URL: https://github.com/llvm/llvm-project/commit/8ac709578067f77a7036fe50610277516fa36d50
DIFF: https://github.com/llvm/llvm-project/commit/8ac709578067f77a7036fe50610277516fa36d50.diff

LOG: [SemaTemplate] Stop passing insertion position around during VarTemplate instantiation

They can get stale at use time because of updates from other recursive
specializations. Instead, rely on the existence of previous declarations to add
the specialization.

Differential Revision: https://reviews.llvm.org/D87853

(cherry picked from commit cffb0dd54d41d8e249d2009467c4beb5b681ba26)

Added: 
    

Modified: 
    clang/include/clang/Sema/Sema.h
    clang/include/clang/Sema/Template.h
    clang/lib/Sema/SemaTemplate.cpp
    clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
    clang/test/SemaTemplate/instantiate-var-template.cpp

Removed: 
    


################################################################################
diff  --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
index 6f7ad8076718..7a7722559397 100644
--- a/clang/include/clang/Sema/Sema.h
+++ b/clang/include/clang/Sema/Sema.h
@@ -9123,7 +9123,7 @@ class Sema final {
       const TemplateArgumentList &TemplateArgList,
       const TemplateArgumentListInfo &TemplateArgsInfo,
       SmallVectorImpl<TemplateArgument> &Converted,
-      SourceLocation PointOfInstantiation, void *InsertPos,
+      SourceLocation PointOfInstantiation,
       LateInstantiatedAttrVec *LateAttrs = nullptr,
       LocalInstantiationScope *StartingScope = nullptr);
   VarTemplateSpecializationDecl *CompleteVarTemplateSpecializationDecl(

diff  --git a/clang/include/clang/Sema/Template.h b/clang/include/clang/Sema/Template.h
index 91d175fdd050..0dcaf565591b 100644
--- a/clang/include/clang/Sema/Template.h
+++ b/clang/include/clang/Sema/Template.h
@@ -600,7 +600,7 @@ enum class TemplateSubstitutionKind : char {
                         TagDecl *NewDecl);
 
     Decl *VisitVarTemplateSpecializationDecl(
-        VarTemplateDecl *VarTemplate, VarDecl *FromVar, void *InsertPos,
+        VarTemplateDecl *VarTemplate, VarDecl *FromVar,
         const TemplateArgumentListInfo &TemplateArgsInfo,
         ArrayRef<TemplateArgument> Converted,
         VarTemplateSpecializationDecl *PrevDecl = nullptr);

diff  --git a/clang/lib/Sema/SemaTemplate.cpp b/clang/lib/Sema/SemaTemplate.cpp
index c05ed0b14e3e..ddae944a48f3 100644
--- a/clang/lib/Sema/SemaTemplate.cpp
+++ b/clang/lib/Sema/SemaTemplate.cpp
@@ -4471,7 +4471,7 @@ Sema::CheckVarTemplateId(VarTemplateDecl *Template, SourceLocation TemplateLoc,
   // FIXME: LateAttrs et al.?
   VarTemplateSpecializationDecl *Decl = BuildVarTemplateInstantiation(
       Template, InstantiationPattern, *InstantiationArgs, TemplateArgs,
-      Converted, TemplateNameLoc, InsertPos /*, LateAttrs, StartingScope*/);
+      Converted, TemplateNameLoc /*, LateAttrs, StartingScope*/);
   if (!Decl)
     return true;
 

diff  --git a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
index baec13ba627c..903785a2be42 100644
--- a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -3602,11 +3602,11 @@ Decl *TemplateDeclInstantiator::VisitVarTemplateSpecializationDecl(
     return nullptr;
 
   return VisitVarTemplateSpecializationDecl(
-      InstVarTemplate, D, InsertPos, VarTemplateArgsInfo, Converted, PrevDecl);
+      InstVarTemplate, D, VarTemplateArgsInfo, Converted, PrevDecl);
 }
 
 Decl *TemplateDeclInstantiator::VisitVarTemplateSpecializationDecl(
-    VarTemplateDecl *VarTemplate, VarDecl *D, void *InsertPos,
+    VarTemplateDecl *VarTemplate, VarDecl *D,
     const TemplateArgumentListInfo &TemplateArgsInfo,
     ArrayRef<TemplateArgument> Converted,
     VarTemplateSpecializationDecl *PrevDecl) {
@@ -3629,8 +3629,11 @@ Decl *TemplateDeclInstantiator::VisitVarTemplateSpecializationDecl(
       SemaRef.Context, Owner, D->getInnerLocStart(), D->getLocation(),
       VarTemplate, DI->getType(), DI, D->getStorageClass(), Converted);
   Var->setTemplateArgsInfo(TemplateArgsInfo);
-  if (InsertPos)
+  if (!PrevDecl) {
+    void *InsertPos = nullptr;
+    VarTemplate->findSpecialization(Converted, InsertPos);
     VarTemplate->AddSpecialization(Var, InsertPos);
+  }
 
   if (SemaRef.getLangOpts().OpenCL)
     SemaRef.deduceOpenCLAddressSpace(Var);
@@ -4839,7 +4842,7 @@ VarTemplateSpecializationDecl *Sema::BuildVarTemplateInstantiation(
     const TemplateArgumentList &TemplateArgList,
     const TemplateArgumentListInfo &TemplateArgsInfo,
     SmallVectorImpl<TemplateArgument> &Converted,
-    SourceLocation PointOfInstantiation, void *InsertPos,
+    SourceLocation PointOfInstantiation,
     LateInstantiatedAttrVec *LateAttrs,
     LocalInstantiationScope *StartingScope) {
   if (FromVar->isInvalidDecl())
@@ -4878,7 +4881,7 @@ VarTemplateSpecializationDecl *Sema::BuildVarTemplateInstantiation(
 
   return cast_or_null<VarTemplateSpecializationDecl>(
       Instantiator.VisitVarTemplateSpecializationDecl(
-          VarTemplate, FromVar, InsertPos, TemplateArgsInfo, Converted));
+          VarTemplate, FromVar, TemplateArgsInfo, Converted));
 }
 
 /// Instantiates a variable template specialization by completing it
@@ -5310,8 +5313,8 @@ void Sema::InstantiateVariableDefinition(SourceLocation PointOfInstantiation,
     TemplateDeclInstantiator Instantiator(*this, Var->getDeclContext(),
                                           TemplateArgs);
     Var = cast_or_null<VarDecl>(Instantiator.VisitVarTemplateSpecializationDecl(
-        VarSpec->getSpecializedTemplate(), Def, nullptr,
-        VarSpec->getTemplateArgsInfo(), VarSpec->getTemplateArgs().asArray()));
+        VarSpec->getSpecializedTemplate(), Def, VarSpec->getTemplateArgsInfo(),
+        VarSpec->getTemplateArgs().asArray(), VarSpec));
     if (Var) {
       llvm::PointerUnion<VarTemplateDecl *,
                          VarTemplatePartialSpecializationDecl *> PatternPtr =
@@ -5321,12 +5324,6 @@ void Sema::InstantiateVariableDefinition(SourceLocation PointOfInstantiation,
         cast<VarTemplateSpecializationDecl>(Var)->setInstantiationOf(
             Partial, &VarSpec->getTemplateInstantiationArgs());
 
-      // Merge the definition with the declaration.
-      LookupResult R(*this, Var->getDeclName(), Var->getLocation(),
-                     LookupOrdinaryName, forRedeclarationInCurContext());
-      R.addDecl(OldVar);
-      MergeVarDecl(Var, R);
-
       // Attach the initializer.
       InstantiateVariableInitializer(Var, Def, TemplateArgs);
     }

diff  --git a/clang/test/SemaTemplate/instantiate-var-template.cpp b/clang/test/SemaTemplate/instantiate-var-template.cpp
index b7b83e4afdd5..a24b205da596 100644
--- a/clang/test/SemaTemplate/instantiate-var-template.cpp
+++ b/clang/test/SemaTemplate/instantiate-var-template.cpp
@@ -40,3 +40,10 @@ namespace PR24483 {
   template<typename... T> A<T...> models;
   template<> struct B models<>; // expected-error {{incomplete type 'struct B'}} expected-note {{forward declaration}}
 }
+
+namespace InvalidInsertPos {
+  template<typename T, int N> T v;
+  template<int N> decltype(v<int, N-1>) v<int, N>;
+  template<> int v<int, 0>;
+  int k = v<int, 500>;
+}