[clang] [llvm] [FlowSensitive] [StatusOr] [3/N] Support absl::Status ops (PR #163868)

[Jan Voung via cfe-commits]

================
@@ -249,13 +262,72 @@ static void transferStatusOrOkCall(const CXXMemberCallExpr *Expr,
   State.Env.setValue(*Expr, OkVal);
 }
 
+static void transferStatusCall(const CXXMemberCallExpr *Expr,
+                               const MatchFinder::MatchResult &,
+                               LatticeTransferState &State) {
+  RecordStorageLocation *StatusOrLoc =
+      getImplicitObjectLocation(*Expr, State.Env);
+  if (StatusOrLoc == nullptr)
+    return;
+
+  RecordStorageLocation &StatusLoc = locForStatus(*StatusOrLoc);
+
+  if (State.Env.getValue(locForOk(StatusLoc)) == nullptr)
+    initializeStatusOr(*StatusOrLoc, State.Env);
+
+  if (Expr->isPRValue())
+    copyRecord(StatusLoc, State.Env.getResultObjectLocation(*Expr), State.Env);
+  else
+    State.Env.setStorageLocation(*Expr, StatusLoc);
+}
+
+static void transferStatusOkCall(const CXXMemberCallExpr *Expr,
+                                 const MatchFinder::MatchResult &,
+                                 LatticeTransferState &State) {
+  RecordStorageLocation *StatusLoc =
+      getImplicitObjectLocation(*Expr, State.Env);
+  if (StatusLoc == nullptr)
+    return;
+
+  if (Value *Val = State.Env.getValue(locForOk(*StatusLoc)))
+    State.Env.setValue(*Expr, *Val);
+}
+
+static void transferStatusUpdateCall(const CXXMemberCallExpr *Expr,
+                                     const MatchFinder::MatchResult &,
+                                     LatticeTransferState &State) {
+  assert(Expr->getNumArgs() == 1);
+  auto *Arg = Expr->getArg(0);
+  RecordStorageLocation *ArgRecord =
+      Arg->isPRValue() ? &State.Env.getResultObjectLocation(*Arg)
+                       : State.Env.get<RecordStorageLocation>(*Arg);
+  RecordStorageLocation *ThisLoc = getImplicitObjectLocation(*Expr, State.Env);
+  if (ThisLoc == nullptr || ArgRecord == nullptr)
+    return;
+
+  auto &ThisOkVal = valForOk(*ThisLoc, State.Env);
----------------
jvoung wrote:

Perhaps leave a brief comment on what "Update" is supposed to do for the reader's convenience to check why this set of assumes, without having to go to the absl sources?

https://github.com/llvm/llvm-project/pull/163868