[FlowSensitive] [StatusOr] [7/N] Support StatusOr::emplace

This always makes the StatusOr OK.

Reviewers: jvoung, Xazax-hun

Reviewed By: jvoung

Pull Request: llvm#163876

Author: fmayer

clang/lib/Analysis/FlowSensitive/Models/UncheckedStatusOrAccessModel.cpp

@@ -516,6 +516,18 @@ static void transferNotOkStatusCall(const CallExpr *Expr,
   State.Env.assume(A.makeNot(OkVal.formula()));
 }
 
+static void transferEmplaceCall(const CXXMemberCallExpr *Expr,
+                                const MatchFinder::MatchResult &,
+                                LatticeTransferState &State) {
+  RecordStorageLocation *StatusOrLoc =
+      getImplicitObjectLocation(*Expr, State.Env);
+  if (StatusOrLoc == nullptr)
+    return;
+
+  auto &OkVal = valForOk(locForStatus(*StatusOrLoc), State.Env);
+  State.Env.assume(OkVal.formula());
+}
+
 CFGMatchSwitch<LatticeTransferState>
 buildTransferMatchSwitch(ASTContext &Ctx,
                          CFGMatchSwitchBuilder<LatticeTransferState> Builder) {
@@ -559,6 +571,8 @@ buildTransferMatchSwitch(ASTContext &Ctx,
           })
       .CaseOfCFGStmt<CallExpr>(isOkStatusCall(), transferOkStatusCall)
       .CaseOfCFGStmt<CallExpr>(isNotOkStatusCall(), transferNotOkStatusCall)
+      .CaseOfCFGStmt<CXXMemberCallExpr>(isStatusOrMemberCallWithName("emplace"),
+                                        transferEmplaceCall)
       .Build();
 }
 

clang/unittests/Analysis/FlowSensitive/UncheckedStatusOrAccessModelTestFixture.cpp

@@ -2928,6 +2928,53 @@ TEST_P(UncheckedStatusOrAccessModelTest, PointerEqualityCheck) {
       )cc");
 }
 
+TEST_P(UncheckedStatusOrAccessModelTest, Emplace) {
+  ExpectDiagnosticsFor(R"cc(
+#include "unchecked_statusor_access_test_defs.h"
+
+    struct Foo {
+      Foo(int);
+    };
+
+    void target(absl::StatusOr<Foo> sor, int value) {
+      sor.emplace(value);
+      sor.value();
+    }
+  )cc");
+  ExpectDiagnosticsFor(R"cc(
+#include "unchecked_statusor_access_test_defs.h"
+
+    struct Foo {
+      Foo(std::initializer_list<int>, int);
+    };
+
+    void target(absl::StatusOr<Foo> sor, int value) {
+      sor.emplace({1, 2, 3}, value);
+      sor.value();
+    }
+  )cc");
+  ExpectDiagnosticsFor(R"cc(
+#include "unchecked_statusor_access_test_defs.h"
+
+    void target() {
+      STATUSOR_INT sor;
+      bool sor_ok = sor.ok();
+      if (!sor_ok)
+        sor.emplace(42);
+      sor.value();
+    }
+  )cc");
+  ExpectDiagnosticsFor(R"cc(
+#include "unchecked_statusor_access_test_defs.h"
+
+    void target(bool b) {
+      STATUSOR_INT sor;
+      if (b) sor.emplace(42);
+      if (b) sor.value();
+    }
+  )cc");
+}
+
 } // namespace
 
 std::string