| //===-- FEnvSafeTest.h -----------------------------------------*- 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 |
| // |
| //===---------------------------------------------------------------------===// |
| |
| #ifndef LLVM_LIBC_TEST_UNITTEST_FPENVSAFE_H |
| #define LLVM_LIBC_TEST_UNITTEST_FPENVSAFE_H |
| |
| #include "hdr/types/fenv_t.h" |
| #include "src/__support/CPP/utility.h" |
| #include "test/UnitTest/Test.h" |
| |
| namespace LIBC_NAMESPACE::testing { |
| |
| // This provides a test fixture (or base class for other test fixtures) that |
| // asserts that each test does not leave the FPU state represented by `fenv_t` |
| // (aka `FPState`) perturbed from its initial state. |
| class FEnvSafeTest : public Test { |
| public: |
| void TearDown() override; |
| |
| protected: |
| // This is an RAII type where `PreserveFEnv preserve{this};` will sample the |
| // `fenv_t` state and restore it when `preserve` goes out of scope. |
| class PreserveFEnv { |
| fenv_t before; |
| FEnvSafeTest &test; |
| |
| public: |
| explicit PreserveFEnv(FEnvSafeTest *self) : test{*self} { |
| test.get_fenv(before); |
| } |
| |
| // Cause test expectation failures if the current state doesn't match what |
| // was captured in the constructor. |
| void check(); |
| |
| // Restore the state captured in the constructor. |
| void restore() { test.set_fenv(before); } |
| |
| ~PreserveFEnv() { restore(); } |
| }; |
| |
| // This is an RAII type where `CheckFEnv check{this};` will sample the |
| // `fenv_t` state and require it be the same when `check` goes out of scope. |
| struct CheckFEnv : public PreserveFEnv { |
| using PreserveFEnv::PreserveFEnv; |
| |
| ~CheckFEnv() { check(); } |
| }; |
| |
| // This calls callable() and returns its value, but has EXPECT_* failures if |
| // the `fenv_t` state is not preserved by the call. |
| template <typename T> decltype(auto) check_fenv_preserved(T &&callable) { |
| CheckFEnv check{this}; |
| return cpp::forward<T>(callable)(); |
| } |
| |
| // This calls callable() and returns its value, but saves and restores the |
| // `fenv_t` state around the call. |
| template <typename T> |
| auto with_fenv_preserved(T &&callable) |
| -> decltype(cpp::forward<decltype(callable)>(callable)()) { |
| PreserveFEnv preserve{this}; |
| return cpp::forward<T>(callable)(); |
| } |
| |
| // A test can call these to indicate it will or won't change `fenv_t` state. |
| void will_change_fenv() { should_be_unchanged = false; } |
| void will_not_change_fenv() { should_be_unchanged = true; } |
| |
| // This explicitly resets back to the "before" state captured in SetUp(). |
| // TearDown() always does this, but should_be_unchanged controls whether |
| // it also causes test failures if a test fails to restore it. |
| void restore_fenv() { check.restore(); } |
| |
| private: |
| void get_fenv(fenv_t &fenv); |
| void set_fenv(const fenv_t &fenv); |
| void expect_fenv_eq(const fenv_t &before_fenv, const fenv_t &after_fenv); |
| |
| CheckFEnv check{this}; |
| |
| // TODO: Many tests fail if this is true. It needs to be figured out whether |
| // the state should be preserved by each library function under test, and |
| // separately whether each test itself should preserve the state. It |
| // probably isn't important that tests be explicitly written to preserve the |
| // state, as the fixture can (and does) reset it--the next test can rely on |
| // getting "normal" ambient state initially. For library functions that |
| // should preserve the state, that should be checked after each call, not |
| // just after the whole test. So they can use check_fenv_preserved or |
| // with_fenv_preserved as appropriate. |
| bool should_be_unchanged = false; |
| }; |
| |
| } // namespace LIBC_NAMESPACE::testing |
| |
| #endif // LLVM_LIBC_TEST_UNITTEST_FPENVSAFE_H |