[clang] [analyzer] Modernize, improve and promote chroot checker (PR #117791)

[via cfe-commits]

================
@@ -121,17 +183,40 @@ void ChrootChecker::checkPreCall(const CallEvent &Call,
     return;
 
   // If jail state is ROOT_CHANGED, generate BugReport.
-  void *const* k = C.getState()->FindGDM(ChrootChecker::getTag());
-  if (k)
-    if (isRootChanged((intptr_t) *k))
-      if (ExplodedNode *N = C.generateNonFatalErrorNode()) {
-        constexpr llvm::StringLiteral Msg =
-            "No call of chdir(\"/\") immediately after chroot";
-        C.emitReport(
-            std::make_unique<PathSensitiveBugReport>(BT_BreakJail, Msg, N));
-      }
+  const ChrootKind k = C.getState()->get<ChrootState>();
+  if (k == ROOT_CHANGED) {
+    ExplodedNode *Err =
+        C.generateNonFatalErrorNode(C.getState(), C.getPredecessor());
+    if (!Err)
+      return;
+    const Expr *ChrootExpr = C.getState()->get<ChrootCall>();
+
+    const ExplodedNode *ChrootCallNode = getAcquisitionSite(Err, C);
+    assert(ChrootCallNode && "Could not find place of stream opening.");
+
+    PathDiagnosticLocation LocUsedForUniqueing;
+    if (const Stmt *ChrootStmt = ChrootCallNode->getStmtForDiagnostics())
+      LocUsedForUniqueing = PathDiagnosticLocation::createBegin(
+          ChrootStmt, C.getSourceManager(),
+          ChrootCallNode->getLocationContext());
----------------
vabridgers wrote:

I took this pattern from the stream checker, I think. I'm wanting to create a more detailed warning message. The checker determines if chdir() was used in an unexpected way and the warning message needs to include information about a prior call to chroot() as a note and warning referring to chdir(). Now that I think about this, maybe this can be simplified. I'll work on it.

https://github.com/llvm/llvm-project/pull/117791