132 lines
4.2 KiB
C++
132 lines
4.2 KiB
C++
// Copyright 2020 The Abseil Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include "absl/base/optimization.h"
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#include "gtest/gtest.h"
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#include "absl/types/optional.h"
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namespace {
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// Tests for the ABSL_PREDICT_TRUE and ABSL_PREDICT_FALSE macros.
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// The tests only verify that the macros are functionally correct - i.e. code
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// behaves as if they weren't used. They don't try to check their impact on
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// optimization.
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TEST(PredictTest, PredictTrue) {
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EXPECT_TRUE(ABSL_PREDICT_TRUE(true));
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EXPECT_FALSE(ABSL_PREDICT_TRUE(false));
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EXPECT_TRUE(ABSL_PREDICT_TRUE(1 == 1));
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EXPECT_FALSE(ABSL_PREDICT_TRUE(1 == 2));
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if (ABSL_PREDICT_TRUE(false)) ADD_FAILURE();
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if (!ABSL_PREDICT_TRUE(true)) ADD_FAILURE();
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EXPECT_TRUE(ABSL_PREDICT_TRUE(true) && true);
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EXPECT_TRUE(ABSL_PREDICT_TRUE(true) || false);
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}
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TEST(PredictTest, PredictFalse) {
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EXPECT_TRUE(ABSL_PREDICT_FALSE(true));
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EXPECT_FALSE(ABSL_PREDICT_FALSE(false));
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EXPECT_TRUE(ABSL_PREDICT_FALSE(1 == 1));
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EXPECT_FALSE(ABSL_PREDICT_FALSE(1 == 2));
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if (ABSL_PREDICT_FALSE(false)) ADD_FAILURE();
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if (!ABSL_PREDICT_FALSE(true)) ADD_FAILURE();
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EXPECT_TRUE(ABSL_PREDICT_FALSE(true) && true);
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EXPECT_TRUE(ABSL_PREDICT_FALSE(true) || false);
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}
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TEST(PredictTest, OneEvaluation) {
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// Verify that the expression is only evaluated once.
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int x = 0;
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if (ABSL_PREDICT_TRUE((++x) == 0)) ADD_FAILURE();
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EXPECT_EQ(x, 1);
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if (ABSL_PREDICT_FALSE((++x) == 0)) ADD_FAILURE();
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EXPECT_EQ(x, 2);
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}
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TEST(PredictTest, OperatorOrder) {
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// Verify that operator order inside and outside the macro behaves well.
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// These would fail for a naive '#define ABSL_PREDICT_TRUE(x) x'
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EXPECT_TRUE(ABSL_PREDICT_TRUE(1 && 2) == true);
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EXPECT_TRUE(ABSL_PREDICT_FALSE(1 && 2) == true);
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EXPECT_TRUE(!ABSL_PREDICT_TRUE(1 == 2));
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EXPECT_TRUE(!ABSL_PREDICT_FALSE(1 == 2));
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}
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TEST(PredictTest, Pointer) {
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const int x = 3;
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const int *good_intptr = &x;
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const int *null_intptr = nullptr;
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EXPECT_TRUE(ABSL_PREDICT_TRUE(good_intptr));
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EXPECT_FALSE(ABSL_PREDICT_TRUE(null_intptr));
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// The following doesn't compile:
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// EXPECT_TRUE(ABSL_PREDICT_FALSE(good_intptr));
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// EXPECT_FALSE(ABSL_PREDICT_FALSE(null_intptr));
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}
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TEST(PredictTest, Optional) {
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// Note: An optional's truth value is the value's existence, not its truth.
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absl::optional<bool> has_value(false);
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absl::optional<bool> no_value;
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EXPECT_TRUE(ABSL_PREDICT_TRUE(has_value));
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EXPECT_FALSE(ABSL_PREDICT_TRUE(no_value));
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// The following doesn't compile:
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// EXPECT_TRUE(ABSL_PREDICT_FALSE(has_value));
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// EXPECT_FALSE(ABSL_PREDICT_FALSE(no_value));
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}
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class ImplictlyConvertibleToBool {
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public:
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explicit ImplictlyConvertibleToBool(bool value) : value_(value) {}
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operator bool() const { // NOLINT(google-explicit-constructor)
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return value_;
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}
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private:
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bool value_;
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};
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TEST(PredictTest, ImplicitBoolConversion) {
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const ImplictlyConvertibleToBool is_true(true);
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const ImplictlyConvertibleToBool is_false(false);
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if (!ABSL_PREDICT_TRUE(is_true)) ADD_FAILURE();
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if (ABSL_PREDICT_TRUE(is_false)) ADD_FAILURE();
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if (!ABSL_PREDICT_FALSE(is_true)) ADD_FAILURE();
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if (ABSL_PREDICT_FALSE(is_false)) ADD_FAILURE();
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}
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class ExplictlyConvertibleToBool {
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public:
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explicit ExplictlyConvertibleToBool(bool value) : value_(value) {}
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explicit operator bool() const { return value_; }
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private:
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bool value_;
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};
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TEST(PredictTest, ExplicitBoolConversion) {
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const ExplictlyConvertibleToBool is_true(true);
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const ExplictlyConvertibleToBool is_false(false);
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if (!ABSL_PREDICT_TRUE(is_true)) ADD_FAILURE();
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if (ABSL_PREDICT_TRUE(is_false)) ADD_FAILURE();
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// The following doesn't compile:
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// if (!ABSL_PREDICT_FALSE(is_true)) ADD_FAILURE();
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// if (ABSL_PREDICT_FALSE(is_false)) ADD_FAILURE();
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}
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} // namespace
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