[clang] [analyzer] Implement binary operations on LazyCompoundVals (PR #106982)

[Donát Nagy via cfe-commits]

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@@ -315,6 +315,62 @@ static bool isFunctionMacroExpansion(SourceLocation Loc,
   return EInfo.isFunctionMacroExpansion();
 }
 
+static const LocationContext *getFirstNonCtorCall(const LocationContext *LCtx) {
+  while (llvm::isa_and_nonnull<CXXConstructorDecl>(LCtx->getDecl()))
+    LCtx = LCtx->getParent();
+  return LCtx;
+}
+
+static const MemRegion *getInitializerRegion(const PostInitializer &PI) {
+  return reinterpret_cast<const MemRegion *>(PI.getLocationValue());
+}
+
+/// Based largely on isInitializationOfVar(). Checks if N initializes FR.
+static bool isInitializationOfField(const ExplodedNode *N,
+                                    const FieldRegion *FR) {
+  std::optional<PostInitializer> P = N->getLocationAs<PostInitializer>();
+  if (!P)
+    return false;
+
+  const MemRegion *InitR = getInitializerRegion(*P);
+
+  if (FR != InitR)
+    return false;
+
+  const MemSpaceRegion *FRSpace = FR->getMemorySpace();
+  const auto *FRCtx = dyn_cast<StackSpaceRegion>(FRSpace);
+
+  if (!FRCtx)
+    return true;
+
+  // The stack frame of N is the constructor, but the FieldRegion is not local
+  // to the constructor, but rather to the caller function.
+  const LocationContext *CallerCtx =
+      getFirstNonCtorCall(N->getLocationContext());
+
+  return FRCtx->getStackFrame() == CallerCtx->getStackFrame();
----------------
NagyDonat wrote:

This looks like you are calling the same method on two different objects of the same type, but IIUC their types are unrelated: `FRCtx` is a `StackSpaceRegion` while `CallerCtx` is a `LocationContext`.

I think it would be helpful to rename `FRCtx` to `FRStackSpace` or something similar to emphasize that it's *not* a (location) context object.

https://github.com/llvm/llvm-project/pull/106982