[ASTImporter] Add Visitor for TypedefNameDecl's

We found a case where Typedef Name Declarations were not being added
correctly when importing builtin types. This exposed the need for a
TypedefNameDecl visitor so these types can be added by RecordDecl and
fields.

This code is covered by the ASTImporterTest cases that use the implicit
struct __NSConstantString_tag definitions.

Thanks to @martong for the debugging assist!

Depends on D83970.

Reviewed By: martong

Differential Revision: https://reviews.llvm.org/D83992

clang/lib/AST/ASTImporterLookupTable.cpp

@@ -22,6 +22,20 @@ namespace {
 struct Builder : RecursiveASTVisitor<Builder> {
   ASTImporterLookupTable &LT;
   Builder(ASTImporterLookupTable &LT) : LT(LT) {}
+
+  bool VisitTypedefNameDecl(TypedefNameDecl *D) {
+    QualType Ty = D->getUnderlyingType();
+    Ty = Ty.getCanonicalType();
+    if (const auto *RTy = dyn_cast<RecordType>(Ty)) {
+      LT.add(RTy->getAsRecordDecl());
+      // iterate over the field decls, adding them
+      for (auto *it : RTy->getAsRecordDecl()->fields()) {
+        LT.add(it);
+      }
+    }
+    return true;
+  }
+
   bool VisitNamedDecl(NamedDecl *D) {
     LT.add(D);
     return true;

clang/test/Analysis/Inputs/ctu-import.c

@@ -0,0 +1,15 @@
+
+// Use an internal, implicitly defined type, called by
+// a function imported for CTU. This should not crash.
+int foo(void);
+int foobar(int skip) {
+  __NSConstantString str = {.flags = 1};
+
+  if (str.flags >= 0)
+    str.flags = 0;
+  return 4;
+}
+
+int testStaticImplicit(void) {
+  return foobar(3);
+}

clang/test/Analysis/Inputs/ctu-import.c.externalDefMap.ast-dump.txt

@@ -0,0 +1 @@
+c:@F@testStaticImplicit ctu-import.c.ast

clang/test/Analysis/ctu-implicit.c

@@ -0,0 +1,20 @@
+// RUN: rm -rf %t && mkdir %t
+// RUN: mkdir -p %t/ctudir2
+// RUN: %clang_cc1  \
+// RUN:   -emit-pch -o %t/ctudir2/ctu-import.c.ast %S/Inputs/ctu-import.c
+// RUN: cp %S/Inputs/ctu-import.c.externalDefMap.ast-dump.txt %t/ctudir2/externalDefMap.txt
+// RUN: %clang_cc1 -analyze \
+// RUN:   -analyzer-checker=core,debug.ExprInspection \
+// RUN:   -analyzer-config experimental-enable-naive-ctu-analysis=true \
+// RUN:   -analyzer-config  display-ctu-progress=true \
+// RUN:   -analyzer-config ctu-dir=%t/ctudir2 \
+// RUN:   -verify %s
+
+void clang_analyzer_eval(int);
+
+int testStaticImplicit(void);
+int func(void) {
+  int ret = testStaticImplicit();
+  clang_analyzer_eval(ret == 4); // expected-warning{{TRUE}}
+  return testStaticImplicit();
+}