[PATCH] log: Allow LOG_DEBUG to always enable log output

[Heinrich Schuchardt]

On 05.08.20 14:56, Tom Rini wrote:
> On Wed, Aug 05, 2020 at 02:54:05PM +0200, Heinrich Schuchardt wrote:
>> On 05.08.20 14:18, Tom Rini wrote:
>>> On Sun, Jul 26, 2020 at 08:27:35PM -0600, Simon Glass wrote:
>>>
>>>> At present if CONFIG_LOG enabled, putting LOG_DEBUG at the top of a file
>>>> (before log.h inclusion) causes _log() to be executed for every log()
>>>> call, regardless of the build- or run-time logging level.
>>>>
>>>> However there is no guarantee that the log record will actually be
>>>> displayed. If the current log level is lower than LOGL_DEBUG then it will
>>>> not be.
>>>>
>>>> Add a way to signal that the log record should always be displayed and
>>>> update log_passes_filters() to handle this.
>>>>
>>>> Signed-off-by: Simon Glass <sjg at chromium.org>
>>>
>>> This exposes an underlying problem with LOG and clang I believe:
>>> https://gitlab.denx.de/u-boot/u-boot/-/jobs/135789
>>>
>>
>> include/log.h:147:44: note: expanded from macro 'log'
>>         if (CONFIG_IS_ENABLED(LOG) && (_LOG_DEBUG || _l <=
>> _LOG_MAX_LEVEL)) \
>>                                                   ^
>> drivers/misc/p2sb_emul.c:197:10: error: converting the enum constant to
>> a boolean [-Werror,-Wint-in-bool-context]
>>
>> This seems to be a Clang bug. _LOG_DEBUG is not an enum:
>>
>> #if CONFIG_IS_ENABLED(LOG)
>> #ifdef LOG_DEBUG
>> #define _LOG_DEBUG      1
>> #else
>> #define _LOG_DEBUG      0
>> #endif
>>
>> So there seems to be a bug in the Clang you used.
>>
>> Compiling with clang on Debian Bullseye does not show the problem:
>>
>> make HOSTCC=clang sandbox_defconfig
>> make HOSTCC=clang CC=clang -j8
>>
>> clang version 9.0.1-13
>> LLVM version 9.0.1
>>
>> Which Clang version did you use?
>>
>> This is the change that added the test:
>> https://reviews.llvm.org/D63082
>>
>> -Wint-in-bool-context seems to be new in Clang 10.
>>
>> All over the U-Boot code we assume that a non-zero integer is true. Do
>> we really want to enable -Wint-in-bool-context?
>
> I'm using the official Clang 10 stable builds.
>

Do you really want to forbid using integers as booleans
(-Wint-in-bool-context)?

Best regards

Heinrich