[PATCH] D25911: [clang-move] Support moving template class forward declarations.

[Haojian Wu via cfe-commits]

hokein created this revision.
hokein added a reviewer: alexfh.
hokein added a subscriber: cfe-commits.

[clang-tidy] Don't warn implicit variables in peformance-unnecessary-copy-initialization.

This will prevent the check warning the variables which have been
implicitly added by compiler, like the following case (in for-range loop):

  the variable '__end' is copy-constructed from a const reference...


https://reviews.llvm.org/D25911

Files:
  clang-move/ClangMove.cpp
  clang-tidy/performance/UnnecessaryCopyInitialization.cpp
  test/clang-tidy/performance-unnecessary-copy-initialization.cpp
  unittests/clang-move/ClangMoveTests.cpp


Index: unittests/clang-move/ClangMoveTests.cpp
===================================================================
--- unittests/clang-move/ClangMoveTests.cpp
+++ unittests/clang-move/ClangMoveTests.cpp
@@ -30,6 +30,7 @@
 
 const char TestHeader[] = "namespace a {\n"
                           "class C1; // test\n"
+                          "template <typename T> class C2;\n"
                           "namespace b {\n"
                           "// This is a Foo class\n"
                           "// which is used in\n"
@@ -87,6 +88,7 @@
 
 const char ExpectedTestHeader[] = "namespace a {\n"
                                   "class C1; // test\n"
+                                  "template <typename T> class C2;\n"
                                   "namespace b {\n"
                                   "\n"
                                   "class Foo2 {\n"
@@ -127,6 +129,7 @@
                                  "#define NEW_FOO_H\n"
                                  "namespace a {\n"
                                  "class C1; // test\n"
+                                 "template <typename T> class C2;\n"
                                  "namespace b {\n"
                                  "// This is a Foo class\n"
                                  "// which is used in\n"
Index: test/clang-tidy/performance-unnecessary-copy-initialization.cpp
===================================================================
--- test/clang-tidy/performance-unnecessary-copy-initialization.cpp
+++ test/clang-tidy/performance-unnecessary-copy-initialization.cpp
@@ -368,3 +368,22 @@
   // CHECK-MESSAGES: [[@LINE-1]]:23: warning: local copy 'copy' of the variable 'orig' is never modified; consider avoiding the copy [performance-unnecessary-copy-initialization]
   // CHECK-FIXES: ExpensiveToCopyType copy = orig, copy2;
 }
+
+class Element {};
+class Container {
+public:
+  class Iterator {
+  public:
+    void operator++();
+    Element operator*();
+    bool operator!=(const Iterator &);
+    WeirdCopyCtorType c;
+  };
+  const Iterator &begin() const;
+  const Iterator &end() const;
+};
+
+void implicitVarFalsePositive() {
+  for (const Element &E : Container()) {
+  }
+}
Index: clang-tidy/performance/UnnecessaryCopyInitialization.cpp
===================================================================
--- clang-tidy/performance/UnnecessaryCopyInitialization.cpp
+++ clang-tidy/performance/UnnecessaryCopyInitialization.cpp
@@ -57,6 +57,7 @@
                    declStmt(
                        has(varDecl(hasLocalStorage(),
                                    hasType(matchers::isExpensiveToCopy()),
+                                   unless(isImplicit()),
                                    hasInitializer(
                                        cxxConstructExpr(
                                            hasDeclaration(cxxConstructorDecl(
Index: clang-move/ClangMove.cpp
===================================================================
--- clang-move/ClangMove.cpp
+++ clang-move/ClangMove.cpp
@@ -406,8 +406,13 @@
   } else if (const auto *FWD =
                  Result.Nodes.getNodeAs<clang::CXXRecordDecl>("fwd_decl")) {
     // Skip all forwad declarations which appear after moved class declaration.
-    if (RemovedDecls.empty())
-      MovedDecls.emplace_back(FWD, &Result.Context->getSourceManager());
+    if (RemovedDecls.empty()) {
+      if (const auto *DCT = FWD->getDescribedClassTemplate()) {
+        MovedDecls.emplace_back(DCT, &Result.Context->getSourceManager());
+      } else {
+        MovedDecls.emplace_back(FWD, &Result.Context->getSourceManager());
+      }
+    }
   } else if (const auto *ANS = Result.Nodes.getNodeAs<clang::NamespaceDecl>(
                  "anonymous_ns")) {
     MovedDecls.emplace_back(ANS, &Result.Context->getSourceManager());


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