1 //===-- Unittests for feholdexcept with exceptions enabled ----------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "src/fenv/feholdexcept.h"
10 
11 #include "src/__support/FPUtil/FEnvUtils.h"
12 #include "src/__support/FPUtil/FPExceptMatcher.h"
13 #include "utils/UnitTest/Test.h"
14 
15 #include <fenv.h>
16 
17 TEST(LlvmLibcFEnvTest, RaiseAndCrash) {
18 #ifdef __aarch64__
19   // Few aarch64 HW implementations do not trap exceptions. We skip this test
20   // completely on such HW.
21   //
22   // Whether HW supports trapping exceptions or not is deduced by enabling an
23   // exception and reading back to see if the exception got enabled. If the
24   // exception did not get enabled, then it means that the HW does not support
25   // trapping exceptions.
26   __llvm_libc::fputil::disableExcept(FE_ALL_EXCEPT);
27   __llvm_libc::fputil::enableExcept(FE_DIVBYZERO);
28   if (__llvm_libc::fputil::getExcept() == 0)
29     return;
30 #endif
31 
32   int excepts[] = {FE_DIVBYZERO, FE_INVALID, FE_INEXACT, FE_OVERFLOW,
33                    FE_UNDERFLOW};
34 
35   for (int e : excepts) {
36     fenv_t env;
37     __llvm_libc::fputil::disableExcept(FE_ALL_EXCEPT);
38     __llvm_libc::fputil::enableExcept(e);
39     ASSERT_EQ(__llvm_libc::fputil::clearExcept(FE_ALL_EXCEPT), 0);
40     ASSERT_EQ(__llvm_libc::feholdexcept(&env), 0);
41     // feholdexcept should disable all excepts so raising an exception
42     // should not crash/invoke the exception handler.
43     ASSERT_EQ(__llvm_libc::fputil::raiseExcept(e), 0);
44 
45     ASSERT_RAISES_FP_EXCEPT([=] {
46       // When we put back the saved env, which has the exception enabled, it
47       // should crash with SIGFPE. Note that we set the old environment
48       // back inside this closure because in some test frameworks like Fuchsia's
49       // zxtest, this test translates to a death test in which this closure is
50       // run in a different thread. So, we set the old environment inside
51       // this closure so that the exception gets enabled for the thread running
52       // this closure.
53       __llvm_libc::fputil::setEnv(&env);
54       __llvm_libc::fputil::raiseExcept(e);
55     });
56 
57     // Cleanup
58     __llvm_libc::fputil::disableExcept(FE_ALL_EXCEPT);
59     ASSERT_EQ(__llvm_libc::fputil::clearExcept(FE_ALL_EXCEPT), 0);
60   }
61 }
62