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-rw-r--r--clang/lib/Analysis/FlowSensitive/Models/UncheckedStatusOrAccessModel.cpp233
1 files changed, 233 insertions, 0 deletions
diff --git a/clang/lib/Analysis/FlowSensitive/Models/UncheckedStatusOrAccessModel.cpp b/clang/lib/Analysis/FlowSensitive/Models/UncheckedStatusOrAccessModel.cpp
index c88a470..598d33a 100644
--- a/clang/lib/Analysis/FlowSensitive/Models/UncheckedStatusOrAccessModel.cpp
+++ b/clang/lib/Analysis/FlowSensitive/Models/UncheckedStatusOrAccessModel.cpp
@@ -24,6 +24,7 @@
#include "clang/Analysis/FlowSensitive/DataflowAnalysis.h"
#include "clang/Analysis/FlowSensitive/DataflowEnvironment.h"
#include "clang/Analysis/FlowSensitive/MatchSwitch.h"
+#include "clang/Analysis/FlowSensitive/RecordOps.h"
#include "clang/Analysis/FlowSensitive/StorageLocation.h"
#include "clang/Analysis/FlowSensitive/Value.h"
#include "clang/Basic/LLVM.h"
@@ -95,6 +96,18 @@ static QualType getStatusOrValueType(ClassTemplateSpecializationDecl *TRD) {
return TRD->getTemplateArgs().get(0).getAsType();
}
+static auto ofClassStatus() {
+ using namespace ::clang::ast_matchers; // NOLINT: Too many names
+ return ofClass(hasName("::absl::Status"));
+}
+
+static auto isStatusMemberCallWithName(llvm::StringRef member_name) {
+ using namespace ::clang::ast_matchers; // NOLINT: Too many names
+ return cxxMemberCallExpr(
+ on(expr(unless(cxxThisExpr()))),
+ callee(cxxMethodDecl(hasName(member_name), ofClassStatus())));
+}
+
static auto isStatusOrMemberCallWithName(llvm::StringRef member_name) {
using namespace ::clang::ast_matchers; // NOLINT: Too many names
return cxxMemberCallExpr(
@@ -124,6 +137,37 @@ static auto valueOperatorCall() {
isStatusOrOperatorCallWithName("->")));
}
+static clang::ast_matchers::TypeMatcher statusType() {
+ using namespace ::clang::ast_matchers; // NOLINT: Too many names
+ return hasCanonicalType(qualType(hasDeclaration(statusClass())));
+}
+
+static auto isComparisonOperatorCall(llvm::StringRef operator_name) {
+ using namespace ::clang::ast_matchers; // NOLINT: Too many names
+ return cxxOperatorCallExpr(
+ hasOverloadedOperatorName(operator_name), argumentCountIs(2),
+ hasArgument(0, anyOf(hasType(statusType()), hasType(statusOrType()))),
+ hasArgument(1, anyOf(hasType(statusType()), hasType(statusOrType()))));
+}
+
+static auto isOkStatusCall() {
+ using namespace ::clang::ast_matchers; // NOLINT: Too many names
+ return callExpr(callee(functionDecl(hasName("::absl::OkStatus"))));
+}
+
+static auto isNotOkStatusCall() {
+ using namespace ::clang::ast_matchers; // NOLINT: Too many names
+ return callExpr(callee(functionDecl(hasAnyName(
+ "::absl::AbortedError", "::absl::AlreadyExistsError",
+ "::absl::CancelledError", "::absl::DataLossError",
+ "::absl::DeadlineExceededError", "::absl::FailedPreconditionError",
+ "::absl::InternalError", "::absl::InvalidArgumentError",
+ "::absl::NotFoundError", "::absl::OutOfRangeError",
+ "::absl::PermissionDeniedError", "::absl::ResourceExhaustedError",
+ "::absl::UnauthenticatedError", "::absl::UnavailableError",
+ "::absl::UnimplementedError", "::absl::UnknownError"))));
+}
+
static auto
buildDiagnoseMatchSwitch(const UncheckedStatusOrAccessModelOptions &Options) {
return CFGMatchSwitchBuilder<const Environment,
@@ -244,6 +288,173 @@ 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) {
+ // S.Update(OtherS) sets S to the error code of OtherS if it is OK,
+ // otherwise does nothing.
+ 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);
+ auto &ArgOkVal = valForOk(*ArgRecord, State.Env);
+ auto &A = State.Env.arena();
+ auto &NewVal = State.Env.makeAtomicBoolValue();
+ State.Env.assume(A.makeImplies(A.makeNot(ThisOkVal.formula()),
+ A.makeNot(NewVal.formula())));
+ State.Env.assume(A.makeImplies(NewVal.formula(), ArgOkVal.formula()));
+ State.Env.setValue(locForOk(*ThisLoc), NewVal);
+}
+
+static BoolValue *evaluateStatusEquality(RecordStorageLocation &LhsStatusLoc,
+ RecordStorageLocation &RhsStatusLoc,
+ Environment &Env) {
+ auto &A = Env.arena();
+ // Logically, a Status object is composed of an error code that could take one
+ // of multiple possible values, including the "ok" value. We track whether a
+ // Status object has an "ok" value and represent this as an `ok` bit. Equality
+ // of Status objects compares their error codes. Therefore, merely comparing
+ // the `ok` bits isn't sufficient: when two Status objects are assigned non-ok
+ // error codes the equality of their respective error codes matters. Since we
+ // only track the `ok` bits, we can't make any conclusions about equality when
+ // we know that two Status objects have non-ok values.
+
+ auto &LhsOkVal = valForOk(LhsStatusLoc, Env);
+ auto &RhsOkVal = valForOk(RhsStatusLoc, Env);
+
+ auto &Res = Env.makeAtomicBoolValue();
+
+ // lhs && rhs => res (a.k.a. !res => !lhs || !rhs)
+ Env.assume(A.makeImplies(A.makeAnd(LhsOkVal.formula(), RhsOkVal.formula()),
+ Res.formula()));
+ // res => (lhs == rhs)
+ Env.assume(A.makeImplies(
+ Res.formula(), A.makeEquals(LhsOkVal.formula(), RhsOkVal.formula())));
+
+ return &Res;
+}
+
+static BoolValue *
+evaluateStatusOrEquality(RecordStorageLocation &LhsStatusOrLoc,
+ RecordStorageLocation &RhsStatusOrLoc,
+ Environment &Env) {
+ auto &A = Env.arena();
+ // Logically, a StatusOr<T> object is composed of two values - a Status and a
+ // value of type T. Equality of StatusOr objects compares both values.
+ // Therefore, merely comparing the `ok` bits of the Status values isn't
+ // sufficient. When two StatusOr objects are engaged, the equality of their
+ // respective values of type T matters. Similarly, when two StatusOr objects
+ // have Status values that have non-ok error codes, the equality of the error
+ // codes matters. Since we only track the `ok` bits of the Status values, we
+ // can't make any conclusions about equality when we know that two StatusOr
+ // objects are engaged or when their Status values contain non-ok error codes.
+ auto &LhsOkVal = valForOk(locForStatus(LhsStatusOrLoc), Env);
+ auto &RhsOkVal = valForOk(locForStatus(RhsStatusOrLoc), Env);
+ auto &res = Env.makeAtomicBoolValue();
+
+ // res => (lhs == rhs)
+ Env.assume(A.makeImplies(
+ res.formula(), A.makeEquals(LhsOkVal.formula(), RhsOkVal.formula())));
+ return &res;
+}
+
+static BoolValue *evaluateEquality(const Expr *LhsExpr, const Expr *RhsExpr,
+ Environment &Env) {
+ // Check the type of both sides in case an operator== is added that admits
+ // different types.
+ if (isStatusOrType(LhsExpr->getType()) &&
+ isStatusOrType(RhsExpr->getType())) {
+ auto *LhsStatusOrLoc = Env.get<RecordStorageLocation>(*LhsExpr);
+ if (LhsStatusOrLoc == nullptr)
+ return nullptr;
+ auto *RhsStatusOrLoc = Env.get<RecordStorageLocation>(*RhsExpr);
+ if (RhsStatusOrLoc == nullptr)
+ return nullptr;
+
+ return evaluateStatusOrEquality(*LhsStatusOrLoc, *RhsStatusOrLoc, Env);
+ }
+ if (isStatusType(LhsExpr->getType()) && isStatusType(RhsExpr->getType())) {
+ auto *LhsStatusLoc = Env.get<RecordStorageLocation>(*LhsExpr);
+ if (LhsStatusLoc == nullptr)
+ return nullptr;
+
+ auto *RhsStatusLoc = Env.get<RecordStorageLocation>(*RhsExpr);
+ if (RhsStatusLoc == nullptr)
+ return nullptr;
+
+ return evaluateStatusEquality(*LhsStatusLoc, *RhsStatusLoc, Env);
+ }
+ return nullptr;
+}
+
+static void transferComparisonOperator(const CXXOperatorCallExpr *Expr,
+ LatticeTransferState &State,
+ bool IsNegative) {
+ auto *LhsAndRhsVal =
+ evaluateEquality(Expr->getArg(0), Expr->getArg(1), State.Env);
+ if (LhsAndRhsVal == nullptr)
+ return;
+
+ if (IsNegative)
+ State.Env.setValue(*Expr, State.Env.makeNot(*LhsAndRhsVal));
+ else
+ State.Env.setValue(*Expr, *LhsAndRhsVal);
+}
+
+static void transferOkStatusCall(const CallExpr *Expr,
+ const MatchFinder::MatchResult &,
+ LatticeTransferState &State) {
+ auto &OkVal =
+ initializeStatus(State.Env.getResultObjectLocation(*Expr), State.Env);
+ State.Env.assume(OkVal.formula());
+}
+
+static void transferNotOkStatusCall(const CallExpr *Expr,
+ const MatchFinder::MatchResult &,
+ LatticeTransferState &State) {
+ auto &OkVal =
+ initializeStatus(State.Env.getResultObjectLocation(*Expr), State.Env);
+ auto &A = State.Env.arena();
+ State.Env.assume(A.makeNot(OkVal.formula()));
+}
+
CFGMatchSwitch<LatticeTransferState>
buildTransferMatchSwitch(ASTContext &Ctx,
CFGMatchSwitchBuilder<LatticeTransferState> Builder) {
@@ -251,6 +462,28 @@ buildTransferMatchSwitch(ASTContext &Ctx,
return std::move(Builder)
.CaseOfCFGStmt<CXXMemberCallExpr>(isStatusOrMemberCallWithName("ok"),
transferStatusOrOkCall)
+ .CaseOfCFGStmt<CXXMemberCallExpr>(isStatusOrMemberCallWithName("status"),
+ transferStatusCall)
+ .CaseOfCFGStmt<CXXMemberCallExpr>(isStatusMemberCallWithName("ok"),
+ transferStatusOkCall)
+ .CaseOfCFGStmt<CXXMemberCallExpr>(isStatusMemberCallWithName("Update"),
+ transferStatusUpdateCall)
+ .CaseOfCFGStmt<CXXOperatorCallExpr>(
+ isComparisonOperatorCall("=="),
+ [](const CXXOperatorCallExpr *Expr, const MatchFinder::MatchResult &,
+ LatticeTransferState &State) {
+ transferComparisonOperator(Expr, State,
+ /*IsNegative=*/false);
+ })
+ .CaseOfCFGStmt<CXXOperatorCallExpr>(
+ isComparisonOperatorCall("!="),
+ [](const CXXOperatorCallExpr *Expr, const MatchFinder::MatchResult &,
+ LatticeTransferState &State) {
+ transferComparisonOperator(Expr, State,
+ /*IsNegative=*/true);
+ })
+ .CaseOfCFGStmt<CallExpr>(isOkStatusCall(), transferOkStatusCall)
+ .CaseOfCFGStmt<CallExpr>(isNotOkStatusCall(), transferNotOkStatusCall)
.Build();
}
generated by cgit v1.1 at 2025-10-23 01:58:28 +0000