[ASTImporter] Add test for C++'s try/catch statements.

[teemperor]

Summary

Also enable exceptions in clang-import-test so that we can parse the test files.

[a_sidorin]

tools/clang-import-test/clang-import-test.cpp

201

Could you please add a newline after RTTI? Now, it looks like the comment is for all lines below.

[teemperor]

• Clarified that the Exception options in LangOpts are not related to the dynamic_cast support by moving them above the comment (Thanks Aleksei!)

test/Import/cxx-try-catch/Inputs/F.cpp

+void f() {
+  try {
+  } catch (...) {
+  }
+
+  try {
+  } catch (int) {
+  }
+
+  try {
+  } catch (int varname) {
+  }
+
+  try {
+  } catch (int varname1) {
+  } catch (long varname2) {
+  }
+}

test/Import/cxx-try-catch/test.cpp

+// RUN: clang-import-test -dump-ast -import %S/Inputs/F.cpp -expression %s | FileCheck %s
+
+// CHECK: CXXTryStmt
+// CHECK-NEXT: CompoundStmt
+// CHECK-NEXT: CXXCatchStmt
+// CHECK-NEXT: <<NULL>>
+// CHECK-NEXT: CompoundStmt
+
+// CHECK: CXXTryStmt
+// CHECK-NEXT: CompoundStmt
+// CHECK-NEXT: CXXCatchStmt
+// CHECK-NEXT: VarDecl
+// CHECK-SAME: 'int'
+// CHECK-NEXT: CompoundStmt
+
+// CHECK: CXXTryStmt
+// CHECK-NEXT: CompoundStmt
+// CHECK-NEXT: CXXCatchStmt
+// CHECK-NEXT: VarDecl
+// CHECK-SAME: varname
+// CHECK-SAME: 'int'
+// CHECK-NEXT: CompoundStmt
+
+// CHECK: CXXTryStmt
+// CHECK-NEXT: CompoundStmt
+// CHECK-NEXT: CXXCatchStmt
+// CHECK-NEXT: VarDecl
+// CHECK-SAME: varname1
+// CHECK-SAME: 'int'
+// CHECK-NEXT: CompoundStmt
+// CHECK-NEXT: CXXCatchStmt
+// CHECK-NEXT: VarDecl
+// CHECK-SAME: varname2
+// CHECK-SAME: 'long'
+// CHECK-NEXT: CompoundStmt
+
+void expr() {
+  f();
+}

tools/clang-import-test/clang-import-test.cpp

std::unique_ptr<CompilerInstance> BuildCompilerInstance() {
   Inv->getLangOpts()->Bool = true;
   Inv->getLangOpts()->WChar = true;
   Inv->getLangOpts()->Blocks = true;
   Inv->getLangOpts()->DebuggerSupport = true;
   Inv->getLangOpts()->SpellChecking = false;
   Inv->getLangOpts()->ThreadsafeStatics = false;
   Inv->getLangOpts()->AccessControl = false;
   Inv->getLangOpts()->DollarIdents = true;
+  Inv->getLangOpts()->Exceptions = true;
+  Inv->getLangOpts()->CXXExceptions = true;
   // Needed for testing dynamic_cast.
   Inv->getLangOpts()->RTTI = true;
   Inv->getCodeGenOpts().setDebugInfo(codegenoptions::FullDebugInfo);
   Inv->getTargetOpts().Triple = llvm::sys::getDefaultTargetTriple();
 
   Ins->setInvocation(std::move(Inv));
 
   TargetInfo *TI = TargetInfo::CreateTargetInfo(
       Ins->getDiagnostics(), Ins->getInvocation().TargetOpts);
   Ins->setTarget(TI);
   Ins->getTarget().adjust(Ins->getLangOpts());