[FlowSensitive] [StatusOr] [15/15] Support references to Status(Or)*

[fmayer]

That hopefully concludes the initial upstreaming.

[llvmbot]

@llvm/pr-subscribers-clang-analysis

@llvm/pr-subscribers-clang

Author: Florian Mayer (fmayer)

Changes

That hopefully concludes the initial upstreaming.

---

Full diff: https://github.com/llvm/llvm-project/pull/170951.diff

2 Files Affected:

• (modified) clang/lib/Analysis/FlowSensitive/Models/UncheckedStatusOrAccessModel.cpp (+65)
• (modified) clang/unittests/Analysis/FlowSensitive/UncheckedStatusOrAccessModelTestFixture.cpp (+50)

diff --git a/clang/lib/Analysis/FlowSensitive/Models/UncheckedStatusOrAccessModel.cpp b/clang/lib/Analysis/FlowSensitive/Models/UncheckedStatusOrAccessModel.cpp
index c917c8e8c11ba..f8439d875d8c7 100644
--- a/clang/lib/Analysis/FlowSensitive/Models/UncheckedStatusOrAccessModel.cpp
+++ b/clang/lib/Analysis/FlowSensitive/Models/UncheckedStatusOrAccessModel.cpp
@@ -351,6 +351,25 @@ static auto isAssertionResultConstructFromBoolCall() {
       hasArgument(0, hasType(booleanType())));
 }
 
+static auto isStatusOrReturningCall() {
+  using namespace ::clang::ast_matchers; // NOLINT: Too many names
+  return callExpr(
+      callee(functionDecl(returns(possiblyReferencedStatusOrType()))));
+}
+
+static auto isStatusOrPtrReturningCall() {
+  using namespace ::clang::ast_matchers; // NOLINT: Too many names
+  return callExpr(callee(functionDecl(returns(hasUnqualifiedDesugaredType(
+      pointerType(pointee(possiblyReferencedStatusOrType())))))));
+}
+
+static auto isStatusPtrReturningCall() {
+  using namespace ::clang::ast_matchers; // NOLINT: Too many names
+  return callExpr(callee(functionDecl(returns(hasUnqualifiedDesugaredType(
+      pointerType(pointee(hasUnqualifiedDesugaredType(
+          recordType(hasDeclaration(statusClass()))))))))));
+}
+
 static auto
 buildDiagnoseMatchSwitch(const UncheckedStatusOrAccessModelOptions &Options) {
   return CFGMatchSwitchBuilder<const Environment,
@@ -1057,6 +1076,40 @@ static void transferArrowCall(const CallExpr *Expr,
                                 StatusOrLoc->getSyntheticField("value")));
 }
 
+static void transferStatusOrPtrReturningCall(const CallExpr *Expr,
+                                             const MatchFinder::MatchResult &,
+                                             LatticeTransferState &State) {
+  PointerValue *PointerVal =
+      dyn_cast_or_null<PointerValue>(State.Env.getValue(*Expr));
+  if (!PointerVal) {
+    PointerVal = cast<PointerValue>(State.Env.createValue(Expr->getType()));
+    State.Env.setValue(*Expr, *PointerVal);
+  }
+
+  auto *RecordLoc =
+      dyn_cast_or_null<RecordStorageLocation>(&PointerVal->getPointeeLoc());
+  if (RecordLoc != nullptr &&
+      State.Env.getValue(locForOk(locForStatus(*RecordLoc))) == nullptr)
+    initializeStatusOr(*RecordLoc, State.Env);
+}
+
+static void transferStatusPtrReturningCall(const CallExpr *Expr,
+                                           const MatchFinder::MatchResult &,
+                                           LatticeTransferState &State) {
+  PointerValue *PointerVal =
+      dyn_cast_or_null<PointerValue>(State.Env.getValue(*Expr));
+  if (!PointerVal) {
+    PointerVal = cast<PointerValue>(State.Env.createValue(Expr->getType()));
+    State.Env.setValue(*Expr, *PointerVal);
+  }
+
+  auto *RecordLoc =
+      dyn_cast_or_null<RecordStorageLocation>(&PointerVal->getPointeeLoc());
+  if (RecordLoc != nullptr &&
+      State.Env.getValue(locForOk(*RecordLoc)) == nullptr)
+    initializeStatus(*RecordLoc, State.Env);
+}
+
 static RecordStorageLocation *
 getSmartPtrLikeStorageLocation(const Expr &E, const Environment &Env) {
   if (!E.isPRValue())
@@ -1209,6 +1262,18 @@ buildTransferMatchSwitch(ASTContext &Ctx,
                                         transferNonConstMemberCall)
       .CaseOfCFGStmt<CXXOperatorCallExpr>(isNonConstMemberOperatorCall(),
                                           transferNonConstMemberOperatorCall)
+      // N.B. this has to be after transferConstMemberCall, otherwise we would
+      // always return a fresh RecordStorageLocation for the StatusOr.
+      .CaseOfCFGStmt<CallExpr>(isStatusOrReturningCall(),
+                               [](const CallExpr *Expr,
+                                  const MatchFinder::MatchResult &,
+                                  LatticeTransferState &State) {
+                                 transferStatusOrReturningCall(Expr, State);
+                               })
+      .CaseOfCFGStmt<CallExpr>(isStatusOrPtrReturningCall(),
+                               transferStatusOrPtrReturningCall)
+      .CaseOfCFGStmt<CallExpr>(isStatusPtrReturningCall(),
+                               transferStatusPtrReturningCall)
       // N.B. These need to come after all other CXXConstructExpr.
       // These are there to make sure that every Status and StatusOr object
       // have their ok boolean initialized when constructed. If we were to
diff --git a/clang/unittests/Analysis/FlowSensitive/UncheckedStatusOrAccessModelTestFixture.cpp b/clang/unittests/Analysis/FlowSensitive/UncheckedStatusOrAccessModelTestFixture.cpp
index cd7353c62f537..c012d0527870b 100644
--- a/clang/unittests/Analysis/FlowSensitive/UncheckedStatusOrAccessModelTestFixture.cpp
+++ b/clang/unittests/Analysis/FlowSensitive/UncheckedStatusOrAccessModelTestFixture.cpp
@@ -3840,6 +3840,56 @@ TEST_P(UncheckedStatusOrAccessModelTest, NestedStatusOrInStatusOrStruct) {
       )cc");
 }
 
+TEST_P(UncheckedStatusOrAccessModelTest, StatusOrPtrReference) {
+  ExpectDiagnosticsFor(R"cc(
+#include "unchecked_statusor_access_test_defs.h"
+
+    const STATUSOR_INT* foo();
+
+    void target() {
+      const auto& sor = foo();
+      if (sor->ok()) sor->value();
+    }
+  )cc");
+
+  ExpectDiagnosticsFor(R"cc(
+#include "unchecked_statusor_access_test_defs.h"
+
+    using StatusOrPtr = const STATUSOR_INT*;
+    StatusOrPtr foo();
+
+    void target() {
+      const auto& sor = foo();
+      if (sor->ok()) sor->value();
+    }
+  )cc");
+}
+
+TEST_P(UncheckedStatusOrAccessModelTest, StatusPtrReference) {
+  ExpectDiagnosticsFor(R"cc(
+#include "unchecked_statusor_access_test_defs.h"
+
+    const STATUS* foo();
+
+    void target(STATUSOR_INT sor) {
+      const auto& s = foo();
+      if (s->ok() && *s == sor.status()) sor.value();
+    }
+  )cc");
+
+  ExpectDiagnosticsFor(R"cc(
+#include "unchecked_statusor_access_test_defs.h"
+
+    using StatusPtr = const STATUS*;
+    StatusPtr foo();
+
+    void target(STATUSOR_INT sor) {
+      const auto& s = foo();
+      if (s->ok() && *s == sor.status()) sor.value();
+    }
+  )cc");
+}
+
 } // namespace
 
 std::string