[analyzer] Generate and use stable identifiers for LocationContext

[george.karpenkov]

Summary

Those are not created in the allocator.
Since they are created fairly rarely, a counter overhead should not affect the memory consumption.

[NoQ]

clang/include/clang/Analysis/AnalysisDeclContext.h

234

This means that for every new analysis the counter will continue rather than reset to 0.

Maybe store the counter in the manager as a non-static field?

[george.karpenkov]

clang/include/clang/Analysis/AnalysisDeclContext.h

234

OK

[NoQ]

Yay!

clang/include/clang/Analysis/AnalysisDeclContext.h

 private:
   ContextKind Kind;
 
   // AnalysisDeclContext can't be const since some methods may modify its
   // member.
   AnalysisDeclContext *Ctx;
 
   const LocationContext *Parent;
+  int64_t ID;
+  static int64_t NewID;
 
 protected:
   LocationContext(ContextKind k, AnalysisDeclContext *ctx,
                   const LocationContext *parent)
-      : Kind(k), Ctx(ctx), Parent(parent) {}
+      : Kind(k), Ctx(ctx), Parent(parent), ID(++NewID) {}
 
 public:
   virtual ~LocationContext();
 
   ContextKind getKind() const { return Kind; }
 
+  int64_t getID() const {
+    return ID;
+  }
+
   AnalysisDeclContext *getAnalysisDeclContext() const { return Ctx; }
 
   const LocationContext *getParent() const { return Parent; }
 
   bool isParentOf(const LocationContext *LC) const;
 
   const Decl *getDecl() const { return getAnalysisDeclContext()->getDecl(); }
 

clang/lib/Analysis/AnalysisDeclContext.cpp

for (const LocationContext *LCtx = this; LCtx; LCtx = LCtx->getParent()) {
     printMoreInfoPerContext(LCtx);
   }
 }
 
 LLVM_DUMP_METHOD void LocationContext::dumpStack() const {
   dumpStack(llvm::errs());
 }
 
+int64_t LocationContext::NewID = 0;
+
 //===----------------------------------------------------------------------===//
 // Lazily generated map to query the external variables referenced by a Block.
 //===----------------------------------------------------------------------===//
 
 namespace {
 
 class FindBlockDeclRefExprsVals : public StmtVisitor<FindBlockDeclRefExprsVals>{
   BumpVector<const VarDecl *> &BEVals;

clang/lib/StaticAnalyzer/Core/Environment.cpp

void Environment::print(raw_ostream &Out, const char *NL,
   WithLC->dumpStack(Out, "", NL, Sep, [&](const LocationContext *LC) {
     for (auto I : ExprBindings) {
       if (I.first.getLocationContext() != LC)
         continue;
 
       const Stmt *S = I.first.getStmt();
       assert(S != nullptr && "Expected non-null Stmt");
 
-      Out << "(LC" << (const void *)LC << ", S" << S->getID(Context) << " <"
-          << (const void *)S << "> ) ";
+      Out << "(LC " << LC->getID() << " <" << (const void *)LC << ">, S "
+          << S->getID(Context) << " <" << (const void *)S << ">) ";
       S->printPretty(Out, /*Helper=*/nullptr, PP);
       Out << " : " << I.second << NL;
     }
   });
 }