[ASTImporter] Merge ExprBits

Summary:
Some `Expr` classes set up default values for the `ExprBits` of `Stmt`.  These
default values are then overwritten by the parser sometimes.  One example is
`InitListExpr` which sets the value kind to be an rvalue in the ctor.  However,
this bit may change after the `InitListExpr` is created.  There may be other
expressions similar to `InitListExpr` in this sense, thus the safest solution
is to copy the expression bits.

The lack of copying `ExprBits` causes an assertion in the analyzer engine in a
specific case: Since the value kind is not imported, the analyzer engine
believes that the given InitListExpr is an rvalue, thus it creates a
nonloc::CompoundVal instead of creating memory region (as in case of an lvalue
reference).

Reviewers: a_sidorin, r.stahl, xazax.hun, a.sidorin

Subscribers: rnkovacs, dkrupp, cfe-commits

Differential Revision: https://reviews.llvm.org/D51533

llvm-svn: 341316

1 files changed, 19 insertions, 0 deletions

diff --git a/clang/unittests/AST/ASTImporterTest.cpp b/clang/unittests/AST/ASTImporterTest.cpp
index c36af16df55..96a8d43cdf1 100644
--- a/clang/unittests/AST/ASTImporterTest.cpp
+++ b/clang/unittests/AST/ASTImporterTest.cpp
@@ -3225,6 +3225,25 @@ TEST_P(ASTImporterTestBase, ClassTemplateFullAndPartialSpecsShouldNotBeMixed) {
                               unless(classTemplatePartialSpecializationDecl()))));
 }
 
+TEST_P(ASTImporterTestBase, InitListExprValueKindShouldBeImported) {
+  Decl *TU = getTuDecl(
+      R"(
+      const int &init();
+      void foo() { const int &a{init()}; }
+      )", Lang_CXX11, "input0.cc");
+  auto *FromD = FirstDeclMatcher<VarDecl>().match(TU, varDecl(hasName("a")));
+  ASSERT_TRUE(FromD->getAnyInitializer());
+  auto *InitExpr = FromD->getAnyInitializer();
+  ASSERT_TRUE(InitExpr);
+  ASSERT_TRUE(InitExpr->isGLValue());
+
+  auto *ToD = Import(FromD, Lang_CXX11);
+  EXPECT_TRUE(ToD);
+  auto *ToInitExpr = cast<VarDecl>(ToD)->getAnyInitializer();
+  EXPECT_TRUE(ToInitExpr);
+  EXPECT_TRUE(ToInitExpr->isGLValue());
+}
+
 struct DeclContextTest : ASTImporterTestBase {};
 
 TEST_P(DeclContextTest, removeDeclOfClassTemplateSpecialization) {