[analyzer] Dump reproducible identifiers for objects under construction.

[NoQ]

Summary

This continues the work that was started in D51826, which now gets applied to object-under-construction tracking for C++.

lib/StaticAnalyzer/Core/ExprEngine.cpp

 public:
   explicit ConstructedObjectKey(const ConstructionContextItem &Item,
                        const LocationContext *LC)
       : Impl(Item, LC) {}
 
   const ConstructionContextItem &getItem() const { return Impl.first; }
   const LocationContext *getLocationContext() const { return Impl.second; }
 
+  ASTContext &getASTContext() const {
+    return getLocationContext()->getDecl()->getASTContext();
+  }
+
   void print(llvm::raw_ostream &OS, PrinterHelper *Helper, PrintingPolicy &PP) {
-    OS << '(' << getLocationContext() << ',' << getAnyASTNodePtr() << ','
-       << getItem().getKindAsString();
+    OS << "(LC" << getLocationContext()->getID() << ',';
+    if (const Stmt *S = getItem().getStmtOrNull())
+      OS << 'S' << S->getID(getASTContext());
+    else
+      OS << 'I' << getItem().getCXXCtorInitializer()->getID(getASTContext());
+    OS << ',' << getItem().getKindAsString();
     if (getItem().getKind() == ConstructionContextItem::ArgumentKind)
       OS << " #" << getItem().getIndex();
     OS << ") ";
     if (const Stmt *S = getItem().getStmtOrNull()) {
       S->printPretty(OS, Helper, PP);
     } else {
       const CXXCtorInitializer *I = getItem().getCXXCtorInitializer();
       OS << I->getAnyMember()->getNameAsString();

test/Analysis/dump_egraph.cpp

 // RUN: %clang_analyze_cc1 -analyzer-checker=core -analyzer-dump-egraph=%t.dot %s
 // RUN: cat %t.dot | FileCheck %s
 // REQUIRES: asserts
 
-
 struct S {
   ~S();
 };
 
+struct T {
+  S s;
+  T() : s() {}
+};
+
 void foo() {
   // Test that dumping symbols conjured on null statements doesn't crash.
-  S s;
+  T t;
 }
 
-// CHECK: conj_$0\{int, LC1, no stmt, #1\}
+// CHECK: (LC1,S{{[0-9]*}},construct into local variable) T t;\n : &t
+// CHECK: (LC2,I{{[0-9]*}},construct into member variable) s : &t-\>s
+// CHECK: conj_$5\{int, LC3, no stmt, #1\}
+