r365585 - [analyzer] CastValueChecker: Model casts
Csaba Dabis via cfe-commits
cfe-commits at lists.llvm.org
Tue Jul 9 17:20:03 PDT 2019
Author: charusso
Date: Tue Jul 9 17:20:03 2019
New Revision: 365585
URL: http://llvm.org/viewvc/llvm-project?rev=365585&view=rev
Log:
[analyzer] CastValueChecker: Model casts
Summary:
It models the LLVM casts:
- `cast<>`
- `dyn_cast<>`
- `cast_or_null<>`
- `dyn_cast_or_null<>`
It has a very basic support without checking the `classof()` function.
(It reapplies the reverted 'llvm-svn: 365582' patch with proper test file.)
Reviewed By: NoQ
Tags: #clang
Differential Revision: https://reviews.llvm.org/D64374
Added:
cfe/trunk/lib/StaticAnalyzer/Checkers/CastValueChecker.cpp
cfe/trunk/test/Analysis/cast-value.cpp
Modified:
cfe/trunk/include/clang/StaticAnalyzer/Checkers/Checkers.td
cfe/trunk/include/clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h
cfe/trunk/lib/StaticAnalyzer/Checkers/CMakeLists.txt
cfe/trunk/test/Analysis/return-value-guaranteed.cpp
Modified: cfe/trunk/include/clang/StaticAnalyzer/Checkers/Checkers.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/StaticAnalyzer/Checkers/Checkers.td?rev=365585&r1=365584&r2=365585&view=diff
==============================================================================
--- cfe/trunk/include/clang/StaticAnalyzer/Checkers/Checkers.td (original)
+++ cfe/trunk/include/clang/StaticAnalyzer/Checkers/Checkers.td Tue Jul 9 17:20:03 2019
@@ -100,6 +100,7 @@ def LLVMAlpha : Package<"llvm">, ParentP
// intended for API modeling that is not controlled by the target triple.
def APIModeling : Package<"apiModeling">, Hidden;
def GoogleAPIModeling : Package<"google">, ParentPackage<APIModeling>, Hidden;
+def LLVMAPIModeling : Package<"llvm">, ParentPackage<APIModeling>, Hidden;
def Debug : Package<"debug">, Hidden;
@@ -274,10 +275,6 @@ def NullableReturnedFromNonnullChecker :
let ParentPackage = APIModeling in {
-def ReturnValueChecker : Checker<"ReturnValue">,
- HelpText<"Model the guaranteed boolean return value of function calls">,
- Documentation<NotDocumented>;
-
def StdCLibraryFunctionsChecker : Checker<"StdCLibraryFunctions">,
HelpText<"Improve modeling of the C standard library functions">,
Documentation<NotDocumented>;
@@ -1109,6 +1106,18 @@ def LLVMConventionsChecker : Checker<"Co
} // end "llvm"
+let ParentPackage = LLVMAPIModeling in {
+
+def CastValueChecker : Checker<"CastValue">,
+ HelpText<"Model implementation of custom RTTIs">,
+ Documentation<NotDocumented>;
+
+def ReturnValueChecker : Checker<"ReturnValue">,
+ HelpText<"Model the guaranteed boolean return value of function calls">,
+ Documentation<NotDocumented>;
+
+} // end "apiModeling.llvm"
+
//===----------------------------------------------------------------------===//
// Checkers modeling Google APIs.
//===----------------------------------------------------------------------===//
Modified: cfe/trunk/include/clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h?rev=365585&r1=365584&r2=365585&view=diff
==============================================================================
--- cfe/trunk/include/clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h (original)
+++ cfe/trunk/include/clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h Tue Jul 9 17:20:03 2019
@@ -247,6 +247,17 @@ public:
IsPrunable);
}
+ /// A shorthand version of getNoteTag that accepts a plain note.
+ ///
+ /// @param Note The note.
+ /// @param IsPrunable Whether the note is prunable. It allows BugReporter
+ /// to omit the note from the report if it would make the displayed
+ /// bug path significantly shorter.
+ const NoteTag *getNoteTag(StringRef Note, bool IsPrunable = false) {
+ return getNoteTag(
+ [Note](BugReporterContext &, BugReport &) { return Note; }, IsPrunable);
+ }
+
/// Returns the word that should be used to refer to the declaration
/// in the report.
StringRef getDeclDescription(const Decl *D);
Modified: cfe/trunk/lib/StaticAnalyzer/Checkers/CMakeLists.txt
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/StaticAnalyzer/Checkers/CMakeLists.txt?rev=365585&r1=365584&r2=365585&view=diff
==============================================================================
--- cfe/trunk/lib/StaticAnalyzer/Checkers/CMakeLists.txt (original)
+++ cfe/trunk/lib/StaticAnalyzer/Checkers/CMakeLists.txt Tue Jul 9 17:20:03 2019
@@ -16,6 +16,7 @@ add_clang_library(clangStaticAnalyzerChe
CallAndMessageChecker.cpp
CastSizeChecker.cpp
CastToStructChecker.cpp
+ CastValueChecker.cpp
CheckObjCDealloc.cpp
CheckObjCInstMethSignature.cpp
CheckSecuritySyntaxOnly.cpp
Added: cfe/trunk/lib/StaticAnalyzer/Checkers/CastValueChecker.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/StaticAnalyzer/Checkers/CastValueChecker.cpp?rev=365585&view=auto
==============================================================================
--- cfe/trunk/lib/StaticAnalyzer/Checkers/CastValueChecker.cpp (added)
+++ cfe/trunk/lib/StaticAnalyzer/Checkers/CastValueChecker.cpp Tue Jul 9 17:20:03 2019
@@ -0,0 +1,191 @@
+//===- CastValueChecker - Model implementation of custom RTTIs --*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This defines CastValueChecker which models casts of custom RTTIs.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
+#include "clang/StaticAnalyzer/Core/Checker.h"
+#include "clang/StaticAnalyzer/Core/CheckerManager.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
+#include "llvm/ADT/Optional.h"
+
+using namespace clang;
+using namespace ento;
+
+namespace {
+class CastValueChecker : public Checker<eval::Call> {
+ using CastCheck =
+ std::function<void(const CastValueChecker *, const CallExpr *,
+ DefinedOrUnknownSVal, CheckerContext &)>;
+
+public:
+ // We have three cases to evaluate a cast:
+ // 1) The parameter is non-null, the return value is non-null
+ // 2) The parameter is non-null, the return value is null
+ // 3) The parameter is null, the return value is null
+ //
+ // cast: 1; dyn_cast: 1, 2; cast_or_null: 1, 3; dyn_cast_or_null: 1, 2, 3.
+ bool evalCall(const CallEvent &Call, CheckerContext &C) const;
+
+private:
+ // These are known in the LLVM project.
+ const CallDescriptionMap<CastCheck> CDM = {
+ {{{"llvm", "cast"}, 1}, &CastValueChecker::evalCast},
+ {{{"llvm", "dyn_cast"}, 1}, &CastValueChecker::evalDynCast},
+ {{{"llvm", "cast_or_null"}, 1}, &CastValueChecker::evalCastOrNull},
+ {{{"llvm", "dyn_cast_or_null"}, 1},
+ &CastValueChecker::evalDynCastOrNull}};
+
+ void evalCast(const CallExpr *CE, DefinedOrUnknownSVal ParamDV,
+ CheckerContext &C) const;
+ void evalDynCast(const CallExpr *CE, DefinedOrUnknownSVal ParamDV,
+ CheckerContext &C) const;
+ void evalCastOrNull(const CallExpr *CE, DefinedOrUnknownSVal ParamDV,
+ CheckerContext &C) const;
+ void evalDynCastOrNull(const CallExpr *CE, DefinedOrUnknownSVal ParamDV,
+ CheckerContext &C) const;
+};
+} // namespace
+
+static std::string getCastName(const Expr *Cast) {
+ return Cast->getType()->getPointeeCXXRecordDecl()->getNameAsString();
+}
+
+static void evalNonNullParamNonNullReturn(const CallExpr *CE,
+ DefinedOrUnknownSVal ParamDV,
+ CheckerContext &C) {
+ ProgramStateRef State = C.getState()->assume(ParamDV, true);
+ if (!State)
+ return;
+
+ State = State->BindExpr(CE, C.getLocationContext(), ParamDV, false);
+
+ std::string CastFromName = getCastName(CE->getArg(0));
+ std::string CastToName = getCastName(CE);
+
+ const NoteTag *CastTag = C.getNoteTag(
+ [CastFromName, CastToName](BugReport &) -> std::string {
+ SmallString<128> Msg;
+ llvm::raw_svector_ostream Out(Msg);
+
+ Out << "Assuming dynamic cast from '" << CastFromName << "' to '"
+ << CastToName << "' succeeds";
+ return Out.str();
+ },
+ /*IsPrunable=*/true);
+
+ C.addTransition(State, CastTag);
+}
+
+static void evalNonNullParamNullReturn(const CallExpr *CE,
+ DefinedOrUnknownSVal ParamDV,
+ CheckerContext &C) {
+ ProgramStateRef State = C.getState()->assume(ParamDV, true);
+ if (!State)
+ return;
+
+ State = State->BindExpr(CE, C.getLocationContext(),
+ C.getSValBuilder().makeNull(), false);
+
+ std::string CastFromName = getCastName(CE->getArg(0));
+ std::string CastToName = getCastName(CE);
+
+ const NoteTag *CastTag = C.getNoteTag(
+ [CastFromName, CastToName](BugReport &) -> std::string {
+ SmallString<128> Msg;
+ llvm::raw_svector_ostream Out(Msg);
+
+ Out << "Assuming dynamic cast from '" << CastFromName << "' to '"
+ << CastToName << "' fails";
+ return Out.str();
+ },
+ /*IsPrunable=*/true);
+
+ C.addTransition(State, CastTag);
+}
+
+static void evalNullParamNullReturn(const CallExpr *CE,
+ DefinedOrUnknownSVal ParamDV,
+ CheckerContext &C) {
+ ProgramStateRef State = C.getState()->assume(ParamDV, false);
+ if (!State)
+ return;
+
+ State = State->BindExpr(CE, C.getLocationContext(),
+ C.getSValBuilder().makeNull(), false);
+
+ const NoteTag *CastTag =
+ C.getNoteTag("Assuming null pointer is passed into cast",
+ /*IsPrunable=*/true);
+
+ C.addTransition(State, CastTag);
+}
+
+void CastValueChecker::evalCast(const CallExpr *CE,
+ DefinedOrUnknownSVal ParamDV,
+ CheckerContext &C) const {
+ evalNonNullParamNonNullReturn(CE, ParamDV, C);
+}
+
+void CastValueChecker::evalDynCast(const CallExpr *CE,
+ DefinedOrUnknownSVal ParamDV,
+ CheckerContext &C) const {
+ evalNonNullParamNonNullReturn(CE, ParamDV, C);
+ evalNonNullParamNullReturn(CE, ParamDV, C);
+}
+
+void CastValueChecker::evalCastOrNull(const CallExpr *CE,
+ DefinedOrUnknownSVal ParamDV,
+ CheckerContext &C) const {
+ evalNonNullParamNonNullReturn(CE, ParamDV, C);
+ evalNullParamNullReturn(CE, ParamDV, C);
+}
+
+void CastValueChecker::evalDynCastOrNull(const CallExpr *CE,
+ DefinedOrUnknownSVal ParamDV,
+ CheckerContext &C) const {
+ evalNonNullParamNonNullReturn(CE, ParamDV, C);
+ evalNonNullParamNullReturn(CE, ParamDV, C);
+ evalNullParamNullReturn(CE, ParamDV, C);
+}
+
+bool CastValueChecker::evalCall(const CallEvent &Call,
+ CheckerContext &C) const {
+ const CastCheck *Check = CDM.lookup(Call);
+ if (!Check)
+ return false;
+
+ Call.getOriginExpr()->dump();
+ const auto *CE = cast<CallExpr>(Call.getOriginExpr());
+ if (!CE)
+ return false;
+
+ // If we cannot obtain both of the classes we cannot be sure how to model it.
+ if (!CE->getType()->getPointeeCXXRecordDecl() ||
+ !CE->getArg(0)->getType()->getPointeeCXXRecordDecl())
+ return false;
+
+ SVal ParamV = Call.getArgSVal(0);
+ auto ParamDV = ParamV.getAs<DefinedOrUnknownSVal>();
+ if (!ParamDV)
+ return false;
+
+ (*Check)(this, CE, *ParamDV, C);
+ return true;
+}
+
+void ento::registerCastValueChecker(CheckerManager &Mgr) {
+ Mgr.registerChecker<CastValueChecker>();
+}
+
+bool ento::shouldRegisterCastValueChecker(const LangOptions &LO) {
+ return true;
+}
Added: cfe/trunk/test/Analysis/cast-value.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/cast-value.cpp?rev=365585&view=auto
==============================================================================
--- cfe/trunk/test/Analysis/cast-value.cpp (added)
+++ cfe/trunk/test/Analysis/cast-value.cpp Tue Jul 9 17:20:03 2019
@@ -0,0 +1,137 @@
+// RUN: %clang_analyze_cc1 \
+// RUN: -analyzer-checker=core,apiModeling.llvm.CastValue,debug.ExprInspection\
+// RUN: -verify=logic %s
+// RUN: %clang_analyze_cc1 \
+// RUN: -analyzer-checker=core,apiModeling.llvm.CastValue \
+// RUN: -analyzer-output=text -verify %s
+
+void clang_analyzer_numTimesReached();
+void clang_analyzer_warnIfReached();
+void clang_analyzer_eval(bool);
+
+namespace llvm {
+template <class X, class Y>
+const X *cast(Y Value);
+
+template <class X, class Y>
+const X *dyn_cast(Y Value);
+
+template <class X, class Y>
+const X *cast_or_null(Y Value);
+
+template <class X, class Y>
+const X *dyn_cast_or_null(Y Value);
+} // namespace llvm
+
+using namespace llvm;
+
+class Shape {};
+class Triangle : public Shape {};
+class Circle : public Shape {};
+
+namespace test_cast {
+void evalLogic(const Shape *S) {
+ const Circle *C = cast<Circle>(S);
+ clang_analyzer_numTimesReached(); // logic-warning {{1}}
+
+ if (S && C)
+ clang_analyzer_eval(C == S); // logic-warning {{TRUE}}
+
+ if (S && !C)
+ clang_analyzer_warnIfReached(); // no-warning
+
+ if (!S)
+ clang_analyzer_warnIfReached(); // no-warning
+}
+} // namespace test_cast
+
+namespace test_dyn_cast {
+void evalLogic(const Shape *S) {
+ const Circle *C = dyn_cast<Circle>(S);
+ clang_analyzer_numTimesReached(); // logic-warning {{2}}
+
+ if (S && C)
+ clang_analyzer_eval(C == S); // logic-warning {{TRUE}}
+
+ if (S && !C)
+ clang_analyzer_warnIfReached(); // logic-warning {{REACHABLE}}
+
+ if (!S)
+ clang_analyzer_warnIfReached(); // no-warning
+}
+} // namespace test_dyn_cast
+
+namespace test_cast_or_null {
+void evalLogic(const Shape *S) {
+ const Circle *C = cast_or_null<Circle>(S);
+ clang_analyzer_numTimesReached(); // logic-warning {{2}}
+
+ if (S && C)
+ clang_analyzer_eval(C == S); // logic-warning {{TRUE}}
+
+ if (S && !C)
+ clang_analyzer_warnIfReached(); // no-warning
+
+ if (!S)
+ clang_analyzer_eval(!C); // logic-warning {{TRUE}}
+}
+} // namespace test_cast_or_null
+
+namespace test_dyn_cast_or_null {
+void evalLogic(const Shape *S) {
+ const Circle *C = dyn_cast_or_null<Circle>(S);
+ clang_analyzer_numTimesReached(); // logic-warning {{3}}
+
+ if (S && C)
+ clang_analyzer_eval(C == S); // logic-warning {{TRUE}}
+
+ if (S && !C)
+ clang_analyzer_warnIfReached(); // logic-warning {{REACHABLE}}
+
+ if (!S)
+ clang_analyzer_eval(!C); // logic-warning {{TRUE}}
+}
+
+void evalNonNullParamNonNullReturn(const Shape *S) {
+ const auto *C = dyn_cast_or_null<Circle>(S);
+ // expected-note at -1 {{Assuming dynamic cast from 'Shape' to 'Circle' succeeds}}
+ // expected-note at -2 {{Assuming pointer value is null}}
+ // expected-note at -3 {{'C' initialized here}}
+
+ (void)(1 / !(bool)C);
+ // expected-note at -1 {{'C' is non-null}}
+ // expected-note at -2 {{Division by zero}}
+ // expected-warning at -3 {{Division by zero}}
+ // logic-warning at -4 {{Division by zero}}
+}
+
+void evalNonNullParamNullReturn(const Shape *S) {
+ const auto *C = dyn_cast_or_null<Circle>(S);
+ // expected-note at -1 {{Assuming dynamic cast from 'Shape' to 'Circle' fails}}
+ // expected-note at -2 {{Assuming pointer value is null}}
+
+ if (const auto *T = dyn_cast_or_null<Triangle>(S)) {
+ // expected-note at -1 {{Assuming dynamic cast from 'Shape' to 'Triangle' succeeds}}
+ // expected-note at -2 {{'T' initialized here}}
+ // expected-note at -3 {{'T' is non-null}}
+ // expected-note at -4 {{Taking true branch}}
+
+ (void)(1 / !T);
+ // expected-note at -1 {{'T' is non-null}}
+ // expected-note at -2 {{Division by zero}}
+ // expected-warning at -3 {{Division by zero}}
+ // logic-warning at -4 {{Division by zero}}
+ }
+}
+
+void evalNullParamNullReturn(const Shape *S) {
+ const auto *C = dyn_cast_or_null<Circle>(S);
+ // expected-note at -1 {{Assuming null pointer is passed into cast}}
+ // expected-note at -2 {{'C' initialized to a null pointer value}}
+
+ (void)(1 / (bool)C);
+ // expected-note at -1 {{Division by zero}}
+ // expected-warning at -2 {{Division by zero}}
+ // logic-warning at -3 {{Division by zero}}
+}
+} // namespace test_dyn_cast_or_null
Modified: cfe/trunk/test/Analysis/return-value-guaranteed.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/return-value-guaranteed.cpp?rev=365585&r1=365584&r2=365585&view=diff
==============================================================================
--- cfe/trunk/test/Analysis/return-value-guaranteed.cpp (original)
+++ cfe/trunk/test/Analysis/return-value-guaranteed.cpp Tue Jul 9 17:20:03 2019
@@ -1,5 +1,5 @@
// RUN: %clang_analyze_cc1 \
-// RUN: -analyzer-checker=core,apiModeling.ReturnValue \
+// RUN: -analyzer-checker=core,apiModeling.llvm.ReturnValue \
// RUN: -analyzer-output=text -verify=class %s
struct Foo { int Field; };
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