r220714 - Frontend: Define __EXCEPTIONS if -fexceptions is passed

[Nico Weber]

Possible, but
http://llvm.org/viewvc/llvm-project?view=revision&revision=139496 suggests
that at least Doug thinks that this is working as intended (that's the
revision that added the test that got its expectations inverted here).

On Thu, Dec 4, 2014 at 5:00 PM, Richard Smith <richard at metafoo.co.uk> wrote:

> This looks like a driver bug; a complete reproducer needs a Darwin triple,
> in order to get exceptions enabled for Obj-C by default:
>
> $ ./build/bin/clang -fno-exceptions -x objective-c++  -target
> x86_64-apple-darwin11 -v /dev/null
> [...]clang-3.6" -cc1 [...] -fexceptions [...]
>
> The issue is that -fno-exceptions has no effect in Objective-C (look at
> the exceptionSettings function in Driver/Tools.cpp and note that an
> explicit -fno-exceptions does *not* turn off ShouldUseExceptionTables; look
> at addExceptionArgs and note that it overrides that flag anyway if we're on
> Darwin).
>
> It seems pretty clear that passing -fno-exceptions to the driver should
> never result in a -cc1 invocation with -fexceptions enabled...
>
> On Thu, Dec 4, 2014 at 4:14 PM, Hans Wennborg <hans at chromium.org> wrote:
>
>> On Mon, Oct 27, 2014 at 1:02 PM, David Majnemer
>> <david.majnemer at gmail.com> wrote:
>> > Author: majnemer
>> > Date: Mon Oct 27 15:02:19 2014
>> > New Revision: 220714
>>
>>
>> This broke Chromium:
>>
>> http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_ng/builds/11730/steps/compile%20%28with%20patch%29/logs/stdio
>>
>> > --- cfe/trunk/test/Preprocessor/predefined-exceptions.m (original)
>> > +++ cfe/trunk/test/Preprocessor/predefined-exceptions.m Mon Oct 27
>> 15:02:19 2014
>> > @@ -1,6 +1,6 @@
>> >  // RUN: %clang_cc1 -x objective-c -fobjc-exceptions -fexceptions -E
>> -dM %s | FileCheck -check-prefix=CHECK-OBJC-NOCXX %s
>> >  // CHECK-OBJC-NOCXX: #define OBJC_ZEROCOST_EXCEPTIONS 1
>> > -// CHECK-OBJC-NOCXX-NOT: #define __EXCEPTIONS 1
>> > +// CHECK-OBJC-NOCXX: #define __EXCEPTIONS 1
>>
>> It seems this reverses the test, and does the opposite of what at
>> least the code I was trying to compile with -fno-exceptions expects:
>>
>> https://code.google.com/p/chromium/codesearch#chromium/src/breakpad/src/client/mac/Framework/Breakpad.mm&l=51
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>>
>
>
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