[clang][AST] Add support for DecompositionDecl to ASTImporter.

BindingDecl was added recently but the related DecompositionDecl is needed
to make C++17 structured bindings importable.
Import of BindingDecl was changed to avoid infinite import loop.

Reviewed By: martong

Differential Revision: https://reviews.llvm.org/D105354

diff --git a/clang/lib/AST/ASTImporter.cpp b/clang/lib/AST/ASTImporter.cpp
index 8fb55488e836a71b1c1950b34d343b7ea6d4902b..787e02029dae7b65772176320ac0698bec9ec502 100644 (file)
--- a/clang/lib/AST/ASTImporter.cpp
+++ b/clang/lib/AST/ASTImporter.cpp
@@ -2302,6 +2302,11 @@ ExpectedDecl ASTNodeImporter::VisitBindingDecl(BindingDecl *D) {
   if (ToND)
     return ToND;
 
+  BindingDecl *ToD;
+  if (GetImportedOrCreateDecl(ToD, D, Importer.getToContext(), DC, Loc,
+                              Name.getAsIdentifierInfo()))
+    return ToD;
+
   Error Err = Error::success();
   QualType ToType = importChecked(Err, D->getType());
   Expr *ToBinding = importChecked(Err, D->getBinding());
@@ -2309,11 +2314,6 @@ ExpectedDecl ASTNodeImporter::VisitBindingDecl(BindingDecl *D) {
   if (Err)
     return std::move(Err);
 
-  BindingDecl *ToD;
-  if (GetImportedOrCreateDecl(ToD, D, Importer.getToContext(), DC, Loc,
-                              Name.getAsIdentifierInfo()))
-    return ToD;
-
   ToD->setBinding(ToType, ToBinding);
   ToD->setDecomposedDecl(ToDecomposedDecl);
   addDeclToContexts(D, ToD);
@@ -4098,14 +4098,26 @@ ExpectedDecl ASTNodeImporter::VisitVarDecl(VarDecl *D) {
   if (Err)
     return std::move(Err);
 
-  // Create the imported variable.
   VarDecl *ToVar;
-  if (GetImportedOrCreateDecl(ToVar, D, Importer.getToContext(), DC,
-                              ToInnerLocStart, Loc,
-                              Name.getAsIdentifierInfo(),
-                              ToType, ToTypeSourceInfo,
-                              D->getStorageClass()))
-    return ToVar;
+  if (auto *FromDecomp = dyn_cast<DecompositionDecl>(D)) {
+    SmallVector<BindingDecl *> Bindings(FromDecomp->bindings().size());
+    if (Error Err =
+            ImportArrayChecked(FromDecomp->bindings(), Bindings.begin()))
+      return std::move(Err);
+    DecompositionDecl *ToDecomp;
+    if (GetImportedOrCreateDecl(
+            ToDecomp, FromDecomp, Importer.getToContext(), DC, ToInnerLocStart,
+            Loc, ToType, ToTypeSourceInfo, D->getStorageClass(), Bindings))
+      return ToDecomp;
+    ToVar = ToDecomp;
+  } else {
+    // Create the imported variable.
+    if (GetImportedOrCreateDecl(ToVar, D, Importer.getToContext(), DC,
+                                ToInnerLocStart, Loc,
+                                Name.getAsIdentifierInfo(), ToType,
+                                ToTypeSourceInfo, D->getStorageClass()))
+      return ToVar;
+  }
 
   ToVar->setTSCSpec(D->getTSCSpec());
   ToVar->setQualifierInfo(ToQualifierLoc);

diff --git a/clang/unittests/AST/ASTImporterTest.cpp b/clang/unittests/AST/ASTImporterTest.cpp
index 3536b1cfcbffcc0b10e1d5e694a8d8e5b734fcae..d49e7c0cd1fef3b849e055097bd0adadb3f60807 100644 (file)
--- a/clang/unittests/AST/ASTImporterTest.cpp
+++ b/clang/unittests/AST/ASTImporterTest.cpp
@@ -3725,6 +3725,32 @@ TEST_P(ImportVariables, ImportBindingDecl) {
   VerifyImport("y3");
 }
 
+TEST_P(ImportVariables, ImportDecompositionDeclArray) {
+  Decl *From, *To;
+  std::tie(From, To) = getImportedDecl(
+      R"(
+      void declToImport() {
+        int a[2] = {1,2};
+        auto [x1,y1] = a;
+      };
+      )",
+      Lang_CXX17, "", Lang_CXX17);
+
+  TranslationUnitDecl *FromTU = From->getTranslationUnitDecl();
+  auto *FromDecomp =
+      FirstDeclMatcher<DecompositionDecl>().match(FromTU, decompositionDecl());
+  auto *ToDecomp = Import(FromDecomp, Lang_CXX17);
+  EXPECT_TRUE(ToDecomp);
+
+  ArrayRef<BindingDecl *> FromB = FromDecomp->bindings();
+  ArrayRef<BindingDecl *> ToB = ToDecomp->bindings();
+  EXPECT_EQ(FromB.size(), ToB.size());
+  for (unsigned int I = 0; I < FromB.size(); ++I) {
+    auto *ToBI = Import(FromB[I], Lang_CXX17);
+    EXPECT_EQ(ToBI, ToB[I]);
+  }
+}
+
 struct ImportClasses : ASTImporterOptionSpecificTestBase {};
 
 TEST_P(ImportClasses, ImportDefinitionWhenProtoIsInNestedToContext) {