[libc] Small adjustments to fenv tests

[michaelrj]

Summary

Some libcs define non-standard FE_* macros and include them in
FE_ALL_EXCEPT. This change adjusts the fenv tests so that the
non-standard FE_* macros do not interfere when compiled with
fenv.h from another libc.

[sivachandra]

libc/test/src/fenv/enabled_exceptions_test.cpp

30

Add a comment here, something like:

We '|' the individual exception flags instead of using FE_ALL_EXCEPT
as it can include non-standard extensions. Note that we should be able
to compile this file with headers from other libcs as well.

libc/test/src/fenv/exception_status_test.cpp

114

You should be able to use allExcepts below instead of FE_ALL_EXCEPT?

[sivachandra]

Accepting now but please land after fixing comments.

[michaelrj]

fix the comments and change the final test in RaiseAndTest

libc/test/src/fenv/enabled_exceptions_test.cpp

TEST(LlvmLibcExceptionStatusTest, RaiseAndCrash) {
   // TODO: Install a floating point exception handler and verify that the
   // the expected exception was raised. One will have to longjmp back from
   // that exception handler, so such a testing can be done after we have
   // longjmp implemented.
 
   int excepts[] = {FE_DIVBYZERO, FE_INVALID, FE_INEXACT, FE_OVERFLOW,
                    FE_UNDERFLOW};
 
+  // We '|' the individual exception flags instead of using FE_ALL_EXCEPT
+  // as it can include non-standard extensions. Note that we should be able
+  // to compile this file with headers from other libcs as well.
+  constexpr int allExcepts =
+      FE_DIVBYZERO | FE_INVALID | FE_INEXACT | FE_OVERFLOW | FE_UNDERFLOW;
+
   for (int e : excepts) {
     ASSERT_DEATH(
         [=] {
           __llvm_libc::fputil::disableExcept(FE_ALL_EXCEPT);
           __llvm_libc::fputil::enableExcept(e);
           ASSERT_EQ(__llvm_libc::feclearexcept(FE_ALL_EXCEPT), 0);
           // Raising all exceptions except |e| should not call the
           // SIGFPE handler. They should set the exception flag though,
           // so we verify that.
-          int others = FE_ALL_EXCEPT & ~e;
+          int others = allExcepts & ~e;
           ASSERT_EQ(__llvm_libc::feraiseexcept(others), 0);
           ASSERT_EQ(__llvm_libc::fetestexcept(others), others);
 
           // We don't check the return value when raising |e| as
           // feraiseexcept will not return when it raises an enabled
           // exception.
           __llvm_libc::feraiseexcept(e);
         },
         SIGFPE);
   }
 }

libc/test/src/fenv/exception_status_test.cpp

TEST(LlvmLibcExceptionStatusTest, RaiseAndTest) {
   // This test raises a set of exceptions and checks that the exception
   // status flags are updated. The intention is really not to invoke the
   // exception handler. Hence, we will disable all exceptions at the
   // beginning.
   __llvm_libc::fputil::disableExcept(FE_ALL_EXCEPT);
 
   int excepts[] = {FE_DIVBYZERO, FE_INVALID, FE_INEXACT, FE_OVERFLOW,
                    FE_UNDERFLOW};
+
+  constexpr int allExcepts =
+      FE_DIVBYZERO | FE_INVALID | FE_INEXACT | FE_OVERFLOW | FE_UNDERFLOW;
+
   for (int e : excepts) {
     int r = __llvm_libc::feraiseexcept(e);
     ASSERT_EQ(r, 0);
     int s = __llvm_libc::fetestexcept(e);
     ASSERT_EQ(s, e);
 
     r = __llvm_libc::feclearexcept(e);
     ASSERT_EQ(r, 0);
for (int e2 : excepts) {
             ASSERT_EQ(r, 0);
             s = __llvm_libc::fetestexcept(e);
             ASSERT_EQ(s, 0);
           }
         }
       }
     }
   }
 
-  int r = __llvm_libc::feraiseexcept(FE_ALL_EXCEPT);
+  int r = __llvm_libc::feraiseexcept(allExcepts);
   ASSERT_EQ(r, 0);
-  int s = __llvm_libc::fetestexcept(FE_ALL_EXCEPT);
-  ASSERT_EQ(s, FE_ALL_EXCEPT);
+  int s = __llvm_libc::fetestexcept(allExcepts);
+  ASSERT_EQ(s, allExcepts);
 }