[cfe-commits] r150306 - in /cfe/trunk: lib/StaticAnalyzer/Checkers/BoolAssignmentChecker.cpp lib/StaticAnalyzer/Checkers/CMakeLists.txt lib/StaticAnalyzer/Checkers/Checkers.td test/Analysis/bool-assignment.cpp test/Analysis/bool-assignment2.c
Ryan Govostes
rzg at apple.com
Sat Feb 11 08:32:09 PST 2012
Author: rgov
Date: Sat Feb 11 10:32:09 2012
New Revision: 150306
URL: http://llvm.org/viewvc/llvm-project?rev=150306&view=rev
Log:
[analyzer] New checker for assignment of non-0/1 values to Boolean variables.
Added:
cfe/trunk/lib/StaticAnalyzer/Checkers/BoolAssignmentChecker.cpp
cfe/trunk/test/Analysis/bool-assignment.cpp
cfe/trunk/test/Analysis/bool-assignment2.c
Modified:
cfe/trunk/lib/StaticAnalyzer/Checkers/CMakeLists.txt
cfe/trunk/lib/StaticAnalyzer/Checkers/Checkers.td
Added: cfe/trunk/lib/StaticAnalyzer/Checkers/BoolAssignmentChecker.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/StaticAnalyzer/Checkers/BoolAssignmentChecker.cpp?rev=150306&view=auto
==============================================================================
--- cfe/trunk/lib/StaticAnalyzer/Checkers/BoolAssignmentChecker.cpp (added)
+++ cfe/trunk/lib/StaticAnalyzer/Checkers/BoolAssignmentChecker.cpp Sat Feb 11 10:32:09 2012
@@ -0,0 +1,157 @@
+//== BoolAssignmentChecker.cpp - Boolean assignment checker -----*- C++ -*--==//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This defines BoolAssignmentChecker, a builtin check in ExprEngine that
+// performs checks for assignment of non-Boolean values to Boolean variables.
+//
+//===----------------------------------------------------------------------===//
+
+#include "ClangSACheckers.h"
+#include "clang/StaticAnalyzer/Core/Checker.h"
+#include "clang/StaticAnalyzer/Core/CheckerManager.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
+#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
+
+using namespace clang;
+using namespace ento;
+
+namespace {
+ class BoolAssignmentChecker : public Checker< check::Bind > {
+ mutable llvm::OwningPtr<BuiltinBug> BT;
+ void emitReport(ProgramStateRef state, CheckerContext &C) const;
+ public:
+ void checkBind(SVal loc, SVal val, const Stmt *S, CheckerContext &C) const;
+ };
+} // end anonymous namespace
+
+void BoolAssignmentChecker::emitReport(ProgramStateRef state,
+ CheckerContext &C) const {
+ if (ExplodedNode *N = C.addTransition(state)) {
+ if (!BT)
+ BT.reset(new BuiltinBug("Assignment of a non-Boolean value"));
+ C.EmitReport(new BugReport(*BT, BT->getDescription(), N));
+ }
+}
+
+static bool isBooleanType(QualType Ty) {
+ if (Ty->isBooleanType()) // C++ or C99
+ return true;
+
+ if (const TypedefType *TT = Ty->getAs<TypedefType>())
+ return TT->getDecl()->getName() == "BOOL" || // Objective-C
+ TT->getDecl()->getName() == "_Bool" || // stdbool.h < C99
+ TT->getDecl()->getName() == "Boolean"; // MacTypes.h
+
+ return false;
+}
+
+void BoolAssignmentChecker::checkBind(SVal loc, SVal val, const Stmt *S,
+ CheckerContext &C) const {
+
+ // We are only interested in stores into Booleans.
+ const TypedValueRegion *TR =
+ dyn_cast_or_null<TypedValueRegion>(loc.getAsRegion());
+
+ if (!TR)
+ return;
+
+ QualType valTy = TR->getValueType();
+
+ if (!isBooleanType(valTy))
+ return;
+
+ // Get the value of the right-hand side. We only care about values
+ // that are defined (UnknownVals and UndefinedVals are handled by other
+ // checkers).
+ const DefinedSVal *DV = dyn_cast<DefinedSVal>(&val);
+ if (!DV)
+ return;
+
+ // Check if the assigned value meets our criteria for correctness. It must
+ // be a value that is either 0 or 1. One way to check this is to see if
+ // the value is possibly < 0 (for a negative value) or greater than 1.
+ ProgramStateRef state = C.getState();
+ SValBuilder &svalBuilder = C.getSValBuilder();
+ ConstraintManager &CM = C.getConstraintManager();
+
+ // First, ensure that the value is >= 0.
+ DefinedSVal zeroVal = svalBuilder.makeIntVal(0, valTy);
+ SVal greaterThanOrEqualToZeroVal =
+ svalBuilder.evalBinOp(state, BO_GE, *DV, zeroVal,
+ svalBuilder.getConditionType());
+
+ DefinedSVal *greaterThanEqualToZero =
+ dyn_cast<DefinedSVal>(&greaterThanOrEqualToZeroVal);
+
+ if (!greaterThanEqualToZero) {
+ // The SValBuilder cannot construct a valid SVal for this condition.
+ // This means we cannot properly reason about it.
+ return;
+ }
+
+ ProgramStateRef stateLT, stateGE;
+ llvm::tie(stateGE, stateLT) = CM.assumeDual(state, *greaterThanEqualToZero);
+
+ // Is it possible for the value to be less than zero?
+ if (stateLT) {
+ // It is possible for the value to be less than zero. We only
+ // want to emit a warning, however, if that value is fully constrained.
+ // If it it possible for the value to be >= 0, then essentially the
+ // value is underconstrained and there is nothing left to be done.
+ if (!stateGE)
+ emitReport(stateLT, C);
+
+ // In either case, we are done.
+ return;
+ }
+
+ // If we reach here, it must be the case that the value is constrained
+ // to only be >= 0.
+ assert(stateGE == state);
+
+ // At this point we know that the value is >= 0.
+ // Now check to ensure that the value is <= 1.
+ DefinedSVal OneVal = svalBuilder.makeIntVal(1, valTy);
+ SVal lessThanEqToOneVal =
+ svalBuilder.evalBinOp(state, BO_LE, *DV, OneVal,
+ svalBuilder.getConditionType());
+
+ DefinedSVal *lessThanEqToOne =
+ dyn_cast<DefinedSVal>(&lessThanEqToOneVal);
+
+ if (!lessThanEqToOne) {
+ // The SValBuilder cannot construct a valid SVal for this condition.
+ // This means we cannot properly reason about it.
+ return;
+ }
+
+ ProgramStateRef stateGT, stateLE;
+ llvm::tie(stateLE, stateGT) = CM.assumeDual(state, *lessThanEqToOne);
+
+ // Is it possible for the value to be greater than one?
+ if (stateGT) {
+ // It is possible for the value to be greater than one. We only
+ // want to emit a warning, however, if that value is fully constrained.
+ // If it is possible for the value to be <= 1, then essentially the
+ // value is underconstrained and there is nothing left to be done.
+ if (!stateLE)
+ emitReport(stateGT, C);
+
+ // In either case, we are done.
+ return;
+ }
+
+ // If we reach here, it must be the case that the value is constrained
+ // to only be <= 1.
+ assert(stateLE == state);
+}
+
+void ento::registerBoolAssignmentChecker(CheckerManager &mgr) {
+ mgr.registerChecker<BoolAssignmentChecker>();
+}
Modified: cfe/trunk/lib/StaticAnalyzer/Checkers/CMakeLists.txt
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/StaticAnalyzer/Checkers/CMakeLists.txt?rev=150306&r1=150305&r2=150306&view=diff
==============================================================================
--- cfe/trunk/lib/StaticAnalyzer/Checkers/CMakeLists.txt (original)
+++ cfe/trunk/lib/StaticAnalyzer/Checkers/CMakeLists.txt Sat Feb 11 10:32:09 2012
@@ -12,6 +12,7 @@
ArrayBoundCheckerV2.cpp
AttrNonNullChecker.cpp
BasicObjCFoundationChecks.cpp
+ BoolAssignmentChecker.cpp
BuiltinFunctionChecker.cpp
CStringChecker.cpp
CStringSyntaxChecker.cpp
Modified: cfe/trunk/lib/StaticAnalyzer/Checkers/Checkers.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/StaticAnalyzer/Checkers/Checkers.td?rev=150306&r1=150305&r2=150306&view=diff
==============================================================================
--- cfe/trunk/lib/StaticAnalyzer/Checkers/Checkers.td (original)
+++ cfe/trunk/lib/StaticAnalyzer/Checkers/Checkers.td Sat Feb 11 10:32:09 2012
@@ -87,6 +87,10 @@
let ParentPackage = CoreExperimental in {
+def BoolAssignmentChecker : Checker<"BoolAssignment">,
+ HelpText<"Warn about assigning non-{0,1} values to Boolean variables">,
+ DescFile<"BoolAssignmentChecker.cpp">;
+
def CastSizeChecker : Checker<"CastSize">,
HelpText<"Check when casting a malloc'ed type T, whether the size is a multiple of the size of T">,
DescFile<"CastSizeChecker.cpp">;
Added: cfe/trunk/test/Analysis/bool-assignment.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/bool-assignment.cpp?rev=150306&view=auto
==============================================================================
--- cfe/trunk/test/Analysis/bool-assignment.cpp (added)
+++ cfe/trunk/test/Analysis/bool-assignment.cpp Sat Feb 11 10:32:09 2012
@@ -0,0 +1,87 @@
+// RUN: %clang_cc1 -analyze -analyzer-checker=core,experimental.core.BoolAssignment -analyzer-store=region -verify %s
+
+// Test C++'s bool
+
+void test_cppbool_initialization(int y) {
+ if (y < 0) {
+ bool x = y; // expected-warning {{Assignment of a non-Boolean value}}
+ return;
+ }
+ if (y > 1) {
+ bool x = y; // expected-warning {{Assignment of a non-Boolean value}}
+ return;
+ }
+ bool x = y; // no-warning
+}
+
+void test_cppbool_assignment(int y) {
+ bool x = 0; // no-warning
+ if (y < 0) {
+ x = y; // expected-warning {{Assignment of a non-Boolean value}}
+ return;
+ }
+ if (y > 1) {
+ x = y; // expected-warning {{Assignment of a non-Boolean value}}
+ return;
+ }
+ x = y; // no-warning
+}
+
+// Test Objective-C's BOOL
+
+typedef signed char BOOL;
+
+void test_BOOL_initialization(int y) {
+ if (y < 0) {
+ BOOL x = y; // expected-warning {{Assignment of a non-Boolean value}}
+ return;
+ }
+ if (y > 1) {
+ BOOL x = y; // expected-warning {{Assignment of a non-Boolean value}}
+ return;
+ }
+ BOOL x = y; // no-warning
+}
+
+void test_BOOL_assignment(int y) {
+ BOOL x = 0; // no-warning
+ if (y < 0) {
+ x = y; // expected-warning {{Assignment of a non-Boolean value}}
+ return;
+ }
+ if (y > 1) {
+ x = y; // expected-warning {{Assignment of a non-Boolean value}}
+ return;
+ }
+ x = y; // no-warning
+}
+
+
+// Test MacTypes.h's Boolean
+
+typedef unsigned char Boolean;
+
+void test_Boolean_initialization(int y) {
+ if (y < 0) {
+ Boolean x = y; // expected-warning {{Assignment of a non-Boolean value}}
+ return;
+ }
+ if (y > 1) {
+ Boolean x = y; // expected-warning {{Assignment of a non-Boolean value}}
+ return;
+ }
+ Boolean x = y; // no-warning
+}
+
+void test_Boolean_assignment(int y) {
+ Boolean x = 0; // no-warning
+ if (y < 0) {
+ x = y; // expected-warning {{Assignment of a non-Boolean value}}
+ return;
+ }
+ if (y > 1) {
+ x = y; // expected-warning {{Assignment of a non-Boolean value}}
+ return;
+ }
+ x = y; // no-warning
+}
Added: cfe/trunk/test/Analysis/bool-assignment2.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/bool-assignment2.c?rev=150306&view=auto
==============================================================================
--- cfe/trunk/test/Analysis/bool-assignment2.c (added)
+++ cfe/trunk/test/Analysis/bool-assignment2.c Sat Feb 11 10:32:09 2012
@@ -0,0 +1,35 @@
+// RUN: %clang_cc1 -std=c99 -analyze -analyzer-checker=core,experimental.core.BoolAssignment -analyzer-store=region -verify %s
+
+// Test stdbool.h's _Bool
+
+// Prior to C99, stdbool.h uses this typedef, but even in ANSI C mode, _Bool
+// appears to be defined.
+
+// #if __STDC_VERSION__ < 199901L
+// typedef int _Bool;
+// #endif
+
+void test_stdbool_initialization(int y) {
+ if (y < 0) {
+ _Bool x = y; // expected-warning {{Assignment of a non-Boolean value}}
+ return;
+ }
+ if (y > 1) {
+ _Bool x = y; // expected-warning {{Assignment of a non-Boolean value}}
+ return;
+ }
+ _Bool x = y; // no-warning
+}
+
+void test_stdbool_assignment(int y) {
+ _Bool x = 0; // no-warning
+ if (y < 0) {
+ x = y; // expected-warning {{Assignment of a non-Boolean value}}
+ return;
+ }
+ if (y > 1) {
+ x = y; // expected-warning {{Assignment of a non-Boolean value}}
+ return;
+ }
+ x = y; // no-warning
+}
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