81 lines
2.5 KiB
C++
81 lines
2.5 KiB
C++
/*
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* Copyright (C) 2019 The Android Open Source Project
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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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* http://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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*/
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#include "gtest/gtest.h"
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#include <cinttypes>
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#include <optional>
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#include <tuple>
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#include "berberis/base/bit_util.h"
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#pragma clang diagnostic push
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// Clang does not allow use of C++ types in “extern "C"” functions - but we need to declare one to
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// test it.
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#pragma clang diagnostic ignored "-Wreturn-type-c-linkage"
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extern "C" std::tuple<uint64_t> AsmTupleTest(std::tuple<uint64_t>*);
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// This function takes first parameter %rdi and uses it as the address of a tuple.
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// If tuple is returned on registers it would contain address of a tuple passed via pointer.
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// If tuple is returned on stack this would be address of the returned tuple (hidden parameter).
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asm(R"(.p2align 4, 0x90
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.type AsmTupleTest,@function
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AsmTupleTest:
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.cfi_startproc
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movl $42, (%rdi)
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movq %rdi, %rax
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ret
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.size AsmTupleTest, .-AsmTupleTest
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.cfi_endproc)");
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#pragma clang diagnostic pop
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namespace berberis {
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namespace {
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std::optional<bool> TupleIsReturnedOnRegisters() {
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std::tuple<uint64_t> result_if_on_regs{};
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std::tuple<uint64_t> result_if_on_stack{};
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result_if_on_stack = AsmTupleTest(&result_if_on_regs);
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if (std::get<uint64_t>(result_if_on_regs) == 42 &&
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std::get<uint64_t>(result_if_on_stack) == bit_cast<uint64_t>(&result_if_on_regs)) {
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return true;
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} else if (std::get<uint64_t>(result_if_on_regs) == 0 &&
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std::get<uint64_t>(result_if_on_stack) == 42) {
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return false;
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} else {
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// Shouldn't happen with proper x86-64 compiler.
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return {};
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}
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}
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// Note: tuple is returned on registers when libc++ is used and on stack if libstdc++ is used.
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TEST(LibCxxAbi, Tuple) {
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auto tuple_is_returned_on_registers = TupleIsReturnedOnRegisters();
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EXPECT_TRUE(tuple_is_returned_on_registers.has_value());
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#ifdef _LIBCPP_VERSION
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EXPECT_TRUE(*tuple_is_returned_on_registers);
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#else
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EXPECT_FALSE(*tuple_is_returned_on_registers);
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#endif
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}
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} // namespace
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} // namespace berberis
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