r368163 - [ASTImporter] Do not import FunctionTemplateDecl in record twice.

[Balazs Keri via cfe-commits]

Author: balazske
Date: Wed Aug  7 05:40:17 2019
New Revision: 368163

URL: http://llvm.org/viewvc/llvm-project?rev=368163&view=rev
Log:
[ASTImporter] Do not import FunctionTemplateDecl in record twice.

Summary:
For functions there is a check to not duplicate the declaration if it is in a
record (class). For function templates there was no similar check, if a
template (in the same class) was imported multiple times the
FunctionTemplateDecl was created multiple times with the same templated
FunctionDecl. This can result in problems with the declaration chain.

Reviewers: martong, a.sidorin, shafik, a_sidorin

Reviewed By: a_sidorin

Subscribers: rnkovacs, dkrupp, Szelethus, gamesh411, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D65203

Modified:
    cfe/trunk/lib/AST/ASTImporter.cpp
    cfe/trunk/unittests/AST/ASTImporterTest.cpp

Modified: cfe/trunk/lib/AST/ASTImporter.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/ASTImporter.cpp?rev=368163&r1=368162&r2=368163&view=diff
==============================================================================
--- cfe/trunk/lib/AST/ASTImporter.cpp (original)
+++ cfe/trunk/lib/AST/ASTImporter.cpp Wed Aug  7 05:40:17 2019
@@ -3118,9 +3118,19 @@ ExpectedDecl ASTNodeImporter::VisitFunct
   if (FoundByLookup) {
     if (isa<CXXMethodDecl>(FoundByLookup)) {
       if (D->getLexicalDeclContext() == D->getDeclContext()) {
-        if (!D->doesThisDeclarationHaveABody())
+        if (!D->doesThisDeclarationHaveABody()) {
+          if (FunctionTemplateDecl *DescribedD =
+                  D->getDescribedFunctionTemplate()) {
+            // Handle a "templated" function together with its described
+            // template. This avoids need for a similar check at import of the
+            // described template.
+            assert(FoundByLookup->getDescribedFunctionTemplate() &&
+                   "Templated function mapped to non-templated?");
+            Importer.MapImported(DescribedD,
+                                 FoundByLookup->getDescribedFunctionTemplate());
+          }
           return Importer.MapImported(D, FoundByLookup);
-        else {
+        } else {
           // Let's continue and build up the redecl chain in this case.
           // FIXME Merge the functions into one decl.
         }

Modified: cfe/trunk/unittests/AST/ASTImporterTest.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/unittests/AST/ASTImporterTest.cpp?rev=368163&r1=368162&r2=368163&view=diff
==============================================================================
--- cfe/trunk/unittests/AST/ASTImporterTest.cpp (original)
+++ cfe/trunk/unittests/AST/ASTImporterTest.cpp Wed Aug  7 05:40:17 2019
@@ -2389,6 +2389,49 @@ TEST_P(ImportFunctions,
                 functionDecl(hasName("f"), hasDescendant(declRefExpr()))))));
 }
 
+struct ImportFunctionTemplates : ASTImporterOptionSpecificTestBase {};
+
+TEST_P(ImportFunctionTemplates, ImportFunctionTemplateInRecordDeclTwice) {
+  auto Code =
+      R"(
+      class X {
+        template <class T>
+        void f(T t);
+      };
+      )";
+  Decl *FromTU1 = getTuDecl(Code, Lang_CXX, "input1.cc");
+  auto *FromD1 = FirstDeclMatcher<FunctionTemplateDecl>().match(
+      FromTU1, functionTemplateDecl(hasName("f")));
+  auto *ToD1 = Import(FromD1, Lang_CXX);
+  Decl *FromTU2 = getTuDecl(Code, Lang_CXX, "input2.cc");
+  auto *FromD2 = FirstDeclMatcher<FunctionTemplateDecl>().match(
+      FromTU2, functionTemplateDecl(hasName("f")));
+  auto *ToD2 = Import(FromD2, Lang_CXX);
+  EXPECT_EQ(ToD1, ToD2);
+}
+
+TEST_P(ImportFunctionTemplates,
+       ImportFunctionTemplateWithDefInRecordDeclTwice) {
+  auto Code =
+      R"(
+      class X {
+        template <class T>
+        void f(T t);
+      };
+      template <class T>
+      void X::f(T t) {};
+      )";
+  Decl *FromTU1 = getTuDecl(Code, Lang_CXX, "input1.cc");
+  auto *FromD1 = FirstDeclMatcher<FunctionTemplateDecl>().match(
+      FromTU1, functionTemplateDecl(hasName("f")));
+  auto *ToD1 = Import(FromD1, Lang_CXX);
+  Decl *FromTU2 = getTuDecl(Code, Lang_CXX, "input2.cc");
+  auto *FromD2 = FirstDeclMatcher<FunctionTemplateDecl>().match(
+      FromTU2, functionTemplateDecl(hasName("f")));
+  auto *ToD2 = Import(FromD2, Lang_CXX);
+  EXPECT_EQ(ToD1, ToD2);
+}
+
 struct ImportFriendFunctions : ImportFunctions {};
 
 TEST_P(ImportFriendFunctions, ImportFriendFunctionRedeclChainProto) {
@@ -5223,6 +5266,9 @@ INSTANTIATE_TEST_CASE_P(ParameterizedTes
 INSTANTIATE_TEST_CASE_P(ParameterizedTests, ImportClasses,
                         DefaultTestValuesForRunOptions, );
 
+INSTANTIATE_TEST_CASE_P(ParameterizedTests, ImportFunctionTemplates,
+                        DefaultTestValuesForRunOptions, );
+
 INSTANTIATE_TEST_CASE_P(ParameterizedTests, ImportFriendFunctions,
                         DefaultTestValuesForRunOptions, );