[analyzer][NFC] Make RegionStore dumps deterministic

Dump the memory space clusters before the other clusters, in
alphabetical order. Then default bindings over direct bindings, and if
any has symbolic offset, then those should come before the ones with
concrete offsets.
In theory, we should either have a symbolic offset OR concrete offsets,
but never both at the same time.

Author: steakhal

clang/lib/StaticAnalyzer/Core/RegionStore.cpp

@@ -67,9 +67,10 @@ class BindingKey {
             isa<ObjCIvarRegion, CXXDerivedObjectRegion>(r)) &&
            "Not a base");
   }
-public:
 
+public:
   bool isDirect() const { return P.getInt() & Direct; }
+  bool isDefault() const { return !isDirect(); }
   bool hasSymbolicOffset() const { return P.getInt() & Symbolic; }
 
   const MemRegion *getRegion() const { return P.getPointer(); }
@@ -232,27 +233,86 @@ class RegionBindingsRef : public llvm::ImmutableMapRef<const MemRegion *,
 
   void printJson(raw_ostream &Out, const char *NL = "\n",
                  unsigned int Space = 0, bool IsDot = false) const {
-    for (iterator I = begin(), E = end(); I != E; ++I) {
-      // TODO: We might need a .printJson for I.getKey() as well.
+    using namespace llvm;
+    DenseMap<const MemRegion *, std::string> StringifyCache;
+    auto ToString = [&StringifyCache](const MemRegion *R) {
+      auto [Place, Inserted] = StringifyCache.try_emplace(R);
+      if (!Inserted)
+        return Place->second;
+      std::string Res;
+      raw_string_ostream OS(Res);
+      OS << R;
+      Place->second = Res;
+      return Res;
+    };
+
+    using Cluster =
+        std::pair<const MemRegion *, ImmutableMap<BindingKey, SVal>>;
+    using Binding = std::pair<BindingKey, SVal>;
+
+    const auto MemSpaceBeforeRegionName = [&ToString](const Cluster *L,
+                                                      const Cluster *R) {
+      if (isa<MemSpaceRegion>(L->first) && !isa<MemSpaceRegion>(R->first))
+        return true;
+      if (!isa<MemSpaceRegion>(L->first) && isa<MemSpaceRegion>(R->first))
+        return false;
+      return ToString(L->first) < ToString(R->first);
+    };
+
+    const auto SymbolicBeforeOffset = [&ToString](const BindingKey &L,
+                                                  const BindingKey &R) {
+      if (L.hasSymbolicOffset() && !R.hasSymbolicOffset())
+        return true;
+      if (!L.hasSymbolicOffset() && R.hasSymbolicOffset())
+        return false;
+      if (L.hasSymbolicOffset() && R.hasSymbolicOffset())
+        return ToString(L.getRegion()) < ToString(R.getRegion());
+      return L.getOffset() < R.getOffset();
+    };
+
+    const auto DefaultBindingBeforeDirectBindings =
+        [&SymbolicBeforeOffset](const Binding *LPtr, const Binding *RPtr) {
+          const BindingKey &L = LPtr->first;
+          const BindingKey &R = RPtr->first;
+          if (L.isDefault() && !R.isDefault())
+            return true;
+          if (!L.isDefault() && R.isDefault())
+            return false;
+          assert(L.isDefault() == R.isDefault());
+          return SymbolicBeforeOffset(L, R);
+        };
+
+    const auto AddrOf = [](const auto &Item) { return &Item; };
+
+    std::vector<const Cluster *> SortedClusters;
+    SortedClusters.reserve(std::distance(begin(), end()));
+    append_range(SortedClusters, map_range(*this, AddrOf));
+    llvm::sort(SortedClusters, MemSpaceBeforeRegionName);
+
+    for (auto [Idx, C] : llvm::enumerate(SortedClusters)) {
+      const auto &[BaseRegion, Bindings] = *C;
       Indent(Out, Space, IsDot)
-          << "{ \"cluster\": \"" << I.getKey() << "\", \"pointer\": \""
-          << (const void *)I.getKey() << "\", \"items\": [" << NL;
+          << "{ \"cluster\": \"" << BaseRegion << "\", \"pointer\": \""
+          << (const void *)BaseRegion << "\", \"items\": [" << NL;
+
+      std::vector<const Binding *> SortedBindings;
+      SortedBindings.reserve(std::distance(Bindings.begin(), Bindings.end()));
+      append_range(SortedBindings, map_range(Bindings, AddrOf));
+      llvm::sort(SortedBindings, DefaultBindingBeforeDirectBindings);
 
       ++Space;
-      const ClusterBindings &CB = I.getData();
-      for (ClusterBindings::iterator CI = CB.begin(), CE = CB.end(); CI != CE;
-           ++CI) {
-        Indent(Out, Space, IsDot) << "{ " << CI.getKey() << ", \"value\": ";
-        CI.getData().printJson(Out, /*AddQuotes=*/true);
+      for (auto [Idx, B] : llvm::enumerate(SortedBindings)) {
+        const auto &[Key, Value] = *B;
+        Indent(Out, Space, IsDot) << "{ " << Key << ", \"value\": ";
+        Value.printJson(Out, /*AddQuotes=*/true);
         Out << " }";
-        if (std::next(CI) != CE)
+        if (Idx != SortedBindings.size() - 1)
           Out << ',';
         Out << NL;
       }
-
       --Space;
       Indent(Out, Space, IsDot) << "]}";
-      if (std::next(I) != E)
+      if (Idx != SortedClusters.size() - 1)
         Out << ',';
       Out << NL;
     }