[OE-core] [PATCH 2/4] ccache.bbclass: Refactor it to make it more reliable

[Robert Yang]

Hi Martin

On 12/10/18 4:55 PM, Martin Hundebøll wrote:
> Hi Robert,
> 
> Just a small nit-pick below..
> 
> On 10/12/2018 03.24, Robert Yang wrote:
>> The previous ccache.bbclass has the following problems:
>> - It uses host's ccache for native recipes, but this may not work on some
>>    hosts, for example, it nerver works on my Ubuntu 14.04.4, there are always
>>    build failures (m4-native failed at do_configure, and others will also be
>>    failed if I disable CCACHE for m4-native)
>>
>> - native/nativesdk/cross/crosssdk recipes use host's ccahe, but target uses
>>    ccache-native, this may confuse user.
>>
>> - The target recipes may use both host's ccache and ccache-native, this may
>>    cause unexpected problems and hard to debug. This is because ccache-native is
>>    in SIGGEN_EXCLUDE_SAFE_RECIPE_DEPS, so ccache-native may not be present when
>>    rebuild target recipes, and then it would use hosttools/ccache, but the
>>    previous ccache files were generated by ccache-native.
>>
>> - Target recipes can't use ccache when no ccahe is installed on the host:
>>    CCACHE = "${@bb.utils.which(d.getVar('PATH'), 'ccache') and 'ccache '}"
>>
>> After refactored:
>> All types recipes (native, target and others) will use ccache-native except
>> ccache-native's dependencies, host's cache won't be used any more. It is more
>> reliable now, which will work everywhere when ccache-native can be built.
>>
>> And now we need use "CCACHE_DISABLE = '1'" to disable ccahe for the recipe
>> rather than "CCACHE = ''" since we set CCACHE in anonymous function, and
>> d.getVar('CCACHE') works after "CCACHE ??=" which is set in bitbake.conf, so we
>> can't check whether CCACHE is set or not in anonymous function since it is
>> always set. Use CCACHE_DISABLE to disable it would be more clear.
>>
>> Signed-off-by: Robert Yang <liezhi.yang at windriver.com>
>> ---
>>   meta/classes/ccache.bbclass             | 25 ++++++++++++++++++++++---
>>   meta/conf/bitbake.conf                  | 21 ++++++++++++++++-----
>>   meta/conf/layer.conf                    |  1 -
>>   meta/lib/oe/utils.py                    |  3 +++
>>   meta/recipes-devtools/ccache/ccache.inc |  2 ++
>>   5 files changed, 43 insertions(+), 9 deletions(-)
>>
> 
> <snip>
> 
>> diff --git a/meta/lib/oe/utils.py b/meta/lib/oe/utils.py
>> index 8a584d6..9c41705 100644
>> --- a/meta/lib/oe/utils.py
>> +++ b/meta/lib/oe/utils.py
>> @@ -363,6 +363,9 @@ def host_gcc_version(d, taskcontextonly=False):
>>           return
>>       compiler = d.getVar("BUILD_CC")
>> +    # Get rid of ccache since it is not present when parsing.
>> +    if compiler.startswith('ccache '):
>> +        compiler = compiler[7:]
> 
> You can avoid the if-condition and hard-coded 7-value by doing:
> 
>    # Get rid of ccache since it is no present when parsing.
>    compiler = d.getVar("BUILD_CC").lstrip("ccache-")

I'm afraid that this may not work, lstrip("ccache-") strips any characters
of 'ccache-' (c, a, h e -), which seems dangerous, and not what we want.
I've will revert it in V2's PULL.

// Robert

> 
> // Martin
> 
>>       try:
>>           env = os.environ.copy()
>>           env["PATH"] = d.getVar("PATH")
>> diff --git a/meta/recipes-devtools/ccache/ccache.inc 
>> b/meta/recipes-devtools/ccache/ccache.inc
>> index 6566328..259c196 100644
>> --- a/meta/recipes-devtools/ccache/ccache.inc
>> +++ b/meta/recipes-devtools/ccache/ccache.inc
>> @@ -9,6 +9,8 @@ LICENSE = "GPLv3+"
>>   DEPENDS = "zlib"
>> +DEPENDS_class-native = "${CCACHE_NATIVE_DEPENDS}"
>> +
>>   SRC_URI = "https://download.samba.org/pub/${BPN}/${BP}.tar.xz"
>>   inherit autotools
>>
>