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//===- unittests/Analysis/FlowSensitive/DataflowAnalysisContextTest.cpp ---===//
//
// 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
//
//===----------------------------------------------------------------------===//
#include "clang/Analysis/FlowSensitive/DataflowAnalysisContext.h"
#include "clang/Analysis/FlowSensitive/WatchedLiteralsSolver.h"
#include "gmock/gmock.h"
#include "gtest/gtest.h"
#include <memory>
namespace {
using namespace clang;
using namespace dataflow;
class DataflowAnalysisContextTest : public ::testing::Test {
protected:
DataflowAnalysisContextTest()
: Context(std::make_unique<WatchedLiteralsSolver>()), A(Context.arena()) {
}
DataflowAnalysisContext Context;
Arena &A;
};
TEST_F(DataflowAnalysisContextTest, DistinctTopsNotEquivalent) {
auto &X = A.makeTopValue();
auto &Y = A.makeTopValue();
EXPECT_FALSE(Context.equivalentFormulas(X.formula(), Y.formula()));
}
TEST_F(DataflowAnalysisContextTest, EmptyFlowCondition) {
Atom FC = A.makeFlowConditionToken();
auto &C = A.makeAtomRef(A.makeAtom());
EXPECT_FALSE(Context.flowConditionImplies(FC, C));
}
TEST_F(DataflowAnalysisContextTest, AddFlowConditionConstraint) {
Atom FC = A.makeFlowConditionToken();
auto &C = A.makeAtomRef(A.makeAtom());
Context.addFlowConditionConstraint(FC, C);
EXPECT_TRUE(Context.flowConditionImplies(FC, C));
}
TEST_F(DataflowAnalysisContextTest, ForkFlowCondition) {
Atom FC1 = A.makeFlowConditionToken();
auto &C1 = A.makeAtomRef(A.makeAtom());
Context.addFlowConditionConstraint(FC1, C1);
// Forked flow condition inherits the constraints of its parent flow
// condition.
Atom FC2 = Context.forkFlowCondition(FC1);
EXPECT_TRUE(Context.flowConditionImplies(FC2, C1));
// Adding a new constraint to the forked flow condition does not affect its
// parent flow condition.
auto &C2 = A.makeAtomRef(A.makeAtom());
Context.addFlowConditionConstraint(FC2, C2);
EXPECT_TRUE(Context.flowConditionImplies(FC2, C2));
EXPECT_FALSE(Context.flowConditionImplies(FC1, C2));
}
TEST_F(DataflowAnalysisContextTest, JoinFlowConditions) {
auto &C1 = A.makeAtomRef(A.makeAtom());
auto &C2 = A.makeAtomRef(A.makeAtom());
auto &C3 = A.makeAtomRef(A.makeAtom());
Atom FC1 = A.makeFlowConditionToken();
Context.addFlowConditionConstraint(FC1, C1);
Context.addFlowConditionConstraint(FC1, C3);
Atom FC2 = A.makeFlowConditionToken();
Context.addFlowConditionConstraint(FC2, C2);
Context.addFlowConditionConstraint(FC2, C3);
Atom FC3 = Context.joinFlowConditions(FC1, FC2);
EXPECT_FALSE(Context.flowConditionImplies(FC3, C1));
EXPECT_FALSE(Context.flowConditionImplies(FC3, C2));
EXPECT_TRUE(Context.flowConditionImplies(FC3, C3));
}
TEST_F(DataflowAnalysisContextTest, FlowConditionTautologies) {
// Fresh flow condition with empty/no constraints is always true.
Atom FC1 = A.makeFlowConditionToken();
EXPECT_TRUE(Context.flowConditionIsTautology(FC1));
// Literal `true` is always true.
Atom FC2 = A.makeFlowConditionToken();
Context.addFlowConditionConstraint(FC2, A.makeLiteral(true));
EXPECT_TRUE(Context.flowConditionIsTautology(FC2));
// Literal `false` is never true.
Atom FC3 = A.makeFlowConditionToken();
Context.addFlowConditionConstraint(FC3, A.makeLiteral(false));
EXPECT_FALSE(Context.flowConditionIsTautology(FC3));
// We can't prove that an arbitrary bool A is always true...
auto &C1 = A.makeAtomRef(A.makeAtom());
Atom FC4 = A.makeFlowConditionToken();
Context.addFlowConditionConstraint(FC4, C1);
EXPECT_FALSE(Context.flowConditionIsTautology(FC4));
// ... but we can prove A || !A is true.
Atom FC5 = A.makeFlowConditionToken();
Context.addFlowConditionConstraint(FC5, A.makeOr(C1, A.makeNot(C1)));
EXPECT_TRUE(Context.flowConditionIsTautology(FC5));
}
TEST_F(DataflowAnalysisContextTest, EquivBoolVals) {
auto &X = A.makeAtomRef(A.makeAtom());
auto &Y = A.makeAtomRef(A.makeAtom());
auto &Z = A.makeAtomRef(A.makeAtom());
auto &True = A.makeLiteral(true);
auto &False = A.makeLiteral(false);
// X == X
EXPECT_TRUE(Context.equivalentFormulas(X, X));
// X != Y
EXPECT_FALSE(Context.equivalentFormulas(X, Y));
// !X != X
EXPECT_FALSE(Context.equivalentFormulas(A.makeNot(X), X));
// !(!X) = X
EXPECT_TRUE(Context.equivalentFormulas(A.makeNot(A.makeNot(X)), X));
// (X || X) == X
EXPECT_TRUE(Context.equivalentFormulas(A.makeOr(X, X), X));
// (X || Y) != X
EXPECT_FALSE(Context.equivalentFormulas(A.makeOr(X, Y), X));
// (X || True) == True
EXPECT_TRUE(Context.equivalentFormulas(A.makeOr(X, True), True));
// (X || False) == X
EXPECT_TRUE(Context.equivalentFormulas(A.makeOr(X, False), X));
// (X && X) == X
EXPECT_TRUE(Context.equivalentFormulas(A.makeAnd(X, X), X));
// (X && Y) != X
EXPECT_FALSE(Context.equivalentFormulas(A.makeAnd(X, Y), X));
// (X && True) == X
EXPECT_TRUE(Context.equivalentFormulas(A.makeAnd(X, True), X));
// (X && False) == False
EXPECT_TRUE(Context.equivalentFormulas(A.makeAnd(X, False), False));
// (X || Y) == (Y || X)
EXPECT_TRUE(Context.equivalentFormulas(A.makeOr(X, Y), A.makeOr(Y, X)));
// (X && Y) == (Y && X)
EXPECT_TRUE(Context.equivalentFormulas(A.makeAnd(X, Y), A.makeAnd(Y, X)));
// ((X || Y) || Z) == (X || (Y || Z))
EXPECT_TRUE(Context.equivalentFormulas(A.makeOr(A.makeOr(X, Y), Z),
A.makeOr(X, A.makeOr(Y, Z))));
// ((X && Y) && Z) == (X && (Y && Z))
EXPECT_TRUE(Context.equivalentFormulas(A.makeAnd(A.makeAnd(X, Y), Z),
A.makeAnd(X, A.makeAnd(Y, Z))));
}
} // namespace
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