test/src/fenv/feholdexcept_test.cpp

//===-- Unittests for feholdexcept with exceptions enabled ----------------===//
//
// 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 "hdr/types/fenv_t.h"
#include "src/fenv/feholdexcept.h"

#include "src/__support/FPUtil/FEnvImpl.h"
#include "src/__support/macros/properties/architectures.h"
#include "test/UnitTest/FEnvSafeTest.h"
#include "test/UnitTest/FPExceptMatcher.h"
#include "test/UnitTest/Test.h"

#include "excepts.h"

using LlvmLibcFEnvTest = LIBC_NAMESPACE::testing::FEnvSafeTest;

TEST_F(LlvmLibcFEnvTest, RaiseAndCrash) {
#if defined(LIBC_TARGET_ARCH_IS_ANY_ARM) ||                                    \
    defined(LIBC_TARGET_ARCH_IS_ANY_RISCV)
  // Few Arm HW implementations do not trap exceptions. We skip this test
  // completely on such HW.
  //
  // Whether HW supports trapping exceptions or not is deduced by enabling an
  // exception and reading back to see if the exception got enabled. If the
  // exception did not get enabled, then it means that the HW does not support
  // trapping exceptions.
  LIBC_NAMESPACE::fputil::disable_except(FE_ALL_EXCEPT);
  LIBC_NAMESPACE::fputil::enable_except(FE_DIVBYZERO);
  if (LIBC_NAMESPACE::fputil::get_except() == 0)
    return;
#endif // Architectures where exception trapping is not supported

  int excepts[] = {FE_DIVBYZERO, FE_INVALID, FE_INEXACT, FE_OVERFLOW,
                   FE_UNDERFLOW};

  for (int e : excepts) {
    fenv_t env;
    LIBC_NAMESPACE::fputil::disable_except(FE_ALL_EXCEPT);
    LIBC_NAMESPACE::fputil::enable_except(e);
    ASSERT_EQ(LIBC_NAMESPACE::fputil::clear_except(FE_ALL_EXCEPT), 0);
    ASSERT_EQ(LIBC_NAMESPACE::feholdexcept(&env), 0);
    // feholdexcept should disable all excepts so raising an exception
    // should not crash/invoke the exception handler.
    ASSERT_EQ(LIBC_NAMESPACE::fputil::raise_except(e), 0);

    ASSERT_RAISES_FP_EXCEPT([=] {
      // When we put back the saved env, which has the exception enabled, it
      // should crash with SIGFPE. Note that we set the old environment
      // back inside this closure because in some test frameworks like Fuchsia's
      // zxtest, this test translates to a death test in which this closure is
      // run in a different thread. So, we set the old environment inside
      // this closure so that the exception gets enabled for the thread running
      // this closure.
      LIBC_NAMESPACE::fputil::set_env(&env);
      LIBC_NAMESPACE::fputil::raise_except(e);
    });

    // Cleanup
    LIBC_NAMESPACE::fputil::disable_except(FE_ALL_EXCEPT);
    ASSERT_EQ(LIBC_NAMESPACE::fputil::clear_except(FE_ALL_EXCEPT), 0);
  }
}