[PATCH] D74639: Add linkage check to ASTNodeImporter::hasSameVisibilityContext and rename to hasSameVisibilityContextAndLinkage

[Shafik Yaghmour via Phabricator via cfe-commits]

shafik created this revision.
shafik added reviewers: martong, teemperor, balazske, a_sidorin.
Herald added a subscriber: rnkovacs.

This fixed is based on the assert in `LinkageComputer::getLVForDecl(…)` which 
assumes that all the decls in a redecl chain have the same linkage.

This change was trigged by a bug that came up when debugging `llc` and running 
the following expression in while in `SelectionDAG::getNode(…)

  p VT.getVectorElementType() == Operand.getValueType()

Evaluating this expression leads to import of an `operator==` for I believe a 
`std::set` iterator. One with external linkage and one with unique external 
linkage but they end in the same redecl chain which triggers the assert in 
`LinkageComputer::getLVForDecl(…)`.

This case has proven difficult to reduce to a minimal test case.


https://reviews.llvm.org/D74639

Files:
  clang/lib/AST/ASTImporter.cpp


Index: clang/lib/AST/ASTImporter.cpp
===================================================================
--- clang/lib/AST/ASTImporter.cpp
+++ clang/lib/AST/ASTImporter.cpp
@@ -463,7 +463,7 @@
                                         ParmVarDecl *ToParam);
 
     template <typename T>
-    bool hasSameVisibilityContext(T *Found, T *From);
+    bool hasSameVisibilityContextAndLinkage(T *Found, T *From);
 
     bool IsStructuralMatch(Decl *From, Decl *To, bool Complain);
     bool IsStructuralMatch(RecordDecl *FromRecord, RecordDecl *ToRecord,
@@ -973,7 +973,10 @@
 }
 
 template <typename T>
-bool ASTNodeImporter::hasSameVisibilityContext(T *Found, T *From) {
+bool ASTNodeImporter::hasSameVisibilityContextAndLinkage(T *Found, T *From) {
+  if (Found->getLinkageInternal() != From->getLinkageInternal())
+    return false;
+
   if (From->hasExternalFormalLinkage())
     return Found->hasExternalFormalLinkage();
   if (Importer.GetFromTU(Found) != From->getTranslationUnitDecl())
@@ -986,8 +989,11 @@
 }
 
 template <>
-bool ASTNodeImporter::hasSameVisibilityContext(TypedefNameDecl *Found,
+bool ASTNodeImporter::hasSameVisibilityContextAndLinkage(TypedefNameDecl *Found,
                                                TypedefNameDecl *From) {
+  if (Found->getLinkageInternal() != From->getLinkageInternal())
+    return false;
+
   if (From->isInAnonymousNamespace() && Found->isInAnonymousNamespace())
     return Importer.GetFromTU(Found) == From->getTranslationUnitDecl();
   return From->isInAnonymousNamespace() == Found->isInAnonymousNamespace();
@@ -2392,7 +2398,7 @@
       if (!FoundDecl->isInIdentifierNamespace(IDNS))
         continue;
       if (auto *FoundTypedef = dyn_cast<TypedefNameDecl>(FoundDecl)) {
-        if (!hasSameVisibilityContext(FoundTypedef, D))
+        if (!hasSameVisibilityContextAndLinkage(FoundTypedef, D))
           continue;
 
         QualType FromUT = D->getUnderlyingType();
@@ -2592,7 +2598,7 @@
       }
 
       if (auto *FoundEnum = dyn_cast<EnumDecl>(FoundDecl)) {
-        if (!hasSameVisibilityContext(FoundEnum, D))
+        if (!hasSameVisibilityContextAndLinkage(FoundEnum, D))
           continue;
         if (IsStructuralMatch(D, FoundEnum))
           return Importer.MapImported(D, FoundEnum);
@@ -2709,7 +2715,7 @@
           if (!IsStructuralMatch(D, FoundRecord, false))
             continue;
 
-        if (!hasSameVisibilityContext(FoundRecord, D))
+        if (!hasSameVisibilityContextAndLinkage(FoundRecord, D))
           continue;
 
         if (IsStructuralMatch(D, FoundRecord)) {
@@ -3157,7 +3163,7 @@
         continue;
 
       if (auto *FoundFunction = dyn_cast<FunctionDecl>(FoundDecl)) {
-        if (!hasSameVisibilityContext(FoundFunction, D))
+        if (!hasSameVisibilityContextAndLinkage(FoundFunction, D))
           continue;
 
         if (IsStructuralMatch(D, FoundFunction)) {
@@ -3779,7 +3785,7 @@
         continue;
 
       if (auto *FoundVar = dyn_cast<VarDecl>(FoundDecl)) {
-        if (!hasSameVisibilityContext(FoundVar, D))
+        if (!hasSameVisibilityContextAndLinkage(FoundVar, D))
           continue;
         if (Importer.IsStructurallyEquivalent(D->getType(),
                                               FoundVar->getType())) {
@@ -5185,7 +5191,7 @@
       Decl *Found = FoundDecl;
       auto *FoundTemplate = dyn_cast<ClassTemplateDecl>(Found);
       if (FoundTemplate) {
-        if (!hasSameVisibilityContext(FoundTemplate, D))
+        if (!hasSameVisibilityContextAndLinkage(FoundTemplate, D))
           continue;
 
         if (IsStructuralMatch(D, FoundTemplate)) {
@@ -5713,7 +5719,7 @@
         continue;
 
       if (auto *FoundTemplate = dyn_cast<FunctionTemplateDecl>(FoundDecl)) {
-        if (!hasSameVisibilityContext(FoundTemplate, D))
+        if (!hasSameVisibilityContextAndLinkage(FoundTemplate, D))
           continue;
         if (IsStructuralMatch(D, FoundTemplate)) {
           FunctionTemplateDecl *TemplateWithDef =

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