Remove a bogus assertion from the AST reader, which assumed that

redeclarations of a particular entity would occur in source
order. Friend declarations that occur within class templates (or
member classes thereof) do not follow this, nor would modules. Big
thanks to Erik Verbruggen for reducing this problem from the Very
Large Qt preamble testcase he found.

llvm-svn: 138557

2 files changed, 67 insertions, 12 deletions

diff --git a/clang/lib/Serialization/ASTReaderDecl.cpp b/clang/lib/Serialization/ASTReaderDecl.cpp
index ab46e0a0962..6e7cbbf9b0c 100644
--- a/clang/lib/Serialization/ASTReaderDecl.cpp
+++ b/clang/lib/Serialization/ASTReaderDecl.cpp
@@ -123,8 +123,8 @@ namespace clang {
                                             ClassTemplateSpecializationDecl *D);
     void VisitClassTemplatePartialSpecializationDecl(
                                      ClassTemplatePartialSpecializationDecl *D);
-    void VisitClassScopeFunctionSpecializationDecl(

-                                       ClassScopeFunctionSpecializationDecl *D);

+    void VisitClassScopeFunctionSpecializationDecl(
+                                       ClassScopeFunctionSpecializationDecl *D);
     void VisitTemplateTypeParmDecl(TemplateTypeParmDecl *D);
     void VisitValueDecl(ValueDecl *VD);
     void VisitEnumConstantDecl(EnumConstantDecl *ECD);
@@ -1087,14 +1087,8 @@ void ASTDeclReader::VisitRedeclarableTemplateDecl(RedeclarableTemplateDecl *D) {
     ASTReader::FirstLatestDeclIDMap::iterator I
         = Reader.FirstLatestDeclIDs.find(ThisDeclID);
     if (I != Reader.FirstLatestDeclIDs.end()) {
-      Decl *NewLatest = Reader.GetDecl(I->second);
-      assert((LatestDecl->getLocation().isInvalid() ||
-              NewLatest->getLocation().isInvalid()  ||
-              !Reader.SourceMgr.isBeforeInTranslationUnit(
-                                                  NewLatest->getLocation(),
-                                                  LatestDecl->getLocation())) &&
-             "The new latest is supposed to come after the previous latest");
-      LatestDecl = cast<RedeclarableTemplateDecl>(NewLatest);
+      if (Decl *NewLatest = Reader.GetDecl(I->second))
+        LatestDecl = cast<RedeclarableTemplateDecl>(NewLatest);
     }
 
     assert(LatestDecl->getKind() == D->getKind() && "Latest kind mismatch");
@@ -1217,8 +1211,8 @@ void ASTDeclReader::VisitClassTemplatePartialSpecializationDecl(
   }
 }
 
-void ASTDeclReader::VisitClassScopeFunctionSpecializationDecl(

-                                    ClassScopeFunctionSpecializationDecl *D) {

+void ASTDeclReader::VisitClassScopeFunctionSpecializationDecl(
+                                    ClassScopeFunctionSpecializationDecl *D) {
   VisitDecl(D);
   D->Specialization = ReadDeclAs<CXXMethodDecl>(Record, Idx);
 }
diff --git a/clang/test/PCH/chain-friend-instantiation.cpp b/clang/test/PCH/chain-friend-instantiation.cpp
new file mode 100644
index 00000000000..294d9791123
--- /dev/null
+++ b/clang/test/PCH/chain-friend-instantiation.cpp
@@ -0,0 +1,61 @@
+// RUN: %clang_cc1 %s -ast-print -o - -chain-include %s -chain-include %s
+
+#if !defined(PASS1)
+#define PASS1
+
+template <class T> class TClass;
+
+namespace NS {
+    template <class X, class Y> TClass<X> problematic(X * ptr, const TClass<Y> &src);
+
+    template <class T>
+    class TBaseClass
+    {
+    protected:
+        template <class X, class Y> friend TClass<X> problematic(X * ptr, const TClass<Y> &src);
+    };
+}
+
+template <class T>
+class TClass: public NS::TBaseClass<T>
+{
+public:
+    inline TClass() { }
+};
+
+
+namespace NS {
+    template <class X, class T>
+    TClass<X> problematic(X *ptr, const TClass<T> &src);
+}
+
+template <class X, class T>
+TClass<X> unconst(const TClass<T> &src);
+
+#elif !defined(PASS2)
+#define PASS2
+
+namespace std {
+class s {};
+}
+
+
+typedef TClass<std::s> TStr;
+
+struct crash {
+  TStr str;
+
+  crash(const TClass<std::s> p)
+  {
+    unconst<TStr>(p);
+  }
+};
+
+#else
+
+void f() {
+    const TStr p;
+    crash c(p);
+}
+
+#endif