[Scons-users] Attaching an emitter to an existing builder

[Bill Deegan]

Not sure what the question is?

You didn't create a PR yet right?

On Tue, Feb 16, 2021 at 9:47 AM Jeremy Elson <jelson at gmail.com> wrote:

> Just wanted to ping yon on the PR above adding native mapfile support to
> scons:
>
> https://github.com/SCons/scons/compare/master...jelson:jelson/scons
> -mapfile
>
> On Sat, Jan 30, 2021 at 4:07 PM Jeremy Elson <jelson at gmail.com> wrote:
>
>> Hi Bill,
>>
>> I'd like to do better than file a bug -- how about a PR?
>>
>>
>> https://github.com/SCons/scons/compare/master...jelson:jelson/scons-mapfile
>>
>> I don't have much experience with SCons internals, so I might have not
>> done this in the most idiomatic way, but I'm open to suggestions how to
>> improve it so I can make it into a PR. I tested this with a simple
>> SConstruct file:
>>
>> Program('prog1.c')
>> Program('prog2.c', mapfile='prog2.map')
>> Program('prog3', source='prog1.c')
>>
>> It generates the output you would expect:
>>
>> gcc -o prog1.o -c prog1.c
>> gcc -o prog1 prog1.o
>> gcc -o prog2.o -c prog2.c
>> gcc -o prog2 prog2.o -Wl,-Map=prog2.map,--cref
>> gcc -o prog3 prog1.o
>>
>> If my implementation is way too off the mark to be useful, I'd be happy
>> to just file a bug instead :)
>>
>> -Jeremy
>>
>>
>> On Fri, Jan 29, 2021 at 10:58 AM Bill Deegan <bill at baddogconsulting.com>
>> wrote:
>>
>>> Jeremy,
>>>
>>> Glad that worked for you!
>>> Please consider filing an enhancement request issue to support
>>> generating map files?
>>>
>>> Thanks,
>>> Bill
>>>
>>> On Thu, Jan 28, 2021 at 4:20 PM Jeremy Elson <jelson at gmail.com> wrote:
>>>
>>>> Thanks, everyone for the help -- PROGEMITTER worked perfectly:
>>>>
>>>>         # Add map creation as a linker flag, and modify the standard
>>>> Program
>>>>         # emitter to know that map generation is a side-effect
>>>>         map_filename = os.path.join(build_obj_dir, f"{target.name
>>>> }.map")
>>>>         env.Append(LINKFLAGS = f"-Wl,-Map={map_filename},--cref")
>>>>         def map_emitter(target, source, env):
>>>>             assert(str(target[0]) == os.path.abspath(program_name))
>>>>             target.append(map_filename)
>>>>             return target, source
>>>>         env.Append(PROGEMITTER = [map_emitter])
>>>>
>>>> My only concern with PROGEMITTER was that it was not a general solution
>>>> to this problem -- i.e., what if I want to override something other than
>>>> Program()? But from looking at MSlink.py as Mats suggested, it seems that
>>>> nearly all the standard builders have similar overrides (SHLIBEMITTER,
>>>> LDMODULEEMITTER, etc). I guess it's similar to the *COMSTR series of
>>>> constants for modifying the message printed at each build step.
>>>>
>>>> Thanks again for a great build system. SCons is a pleasure to use.
>>>>
>>>> -Jeremy
>>>>
>>>>
>>>>
>>>> On Thu, Jan 28, 2021 at 7:19 AM Mats Wichmann <mats at wichmann.us> wrote:
>>>>
>>>>> On 1/27/21 3:11 PM, Bill Deegan wrote:
>>>>> > Jeremy,
>>>>> >
>>>>> > Greetings!
>>>>> > You're not the first to mention adding the map file as a side
>>>>> effect.
>>>>> > (or target)
>>>>> > Please go ahead and file and Issue on github for this.
>>>>> > Ideally with a simple example, what the gcc flag is, and what the
>>>>> file
>>>>> > naming/location would be?
>>>>> >
>>>>> > So likely the easiest way to add an emitter to Program() would be
>>>>> the
>>>>> > following (not tested)
>>>>> >
>>>>> > env.Append(PROGEMITTER = [my_map_emitter])
>>>>> >
>>>>> > Give that a try and let us know if it works for you?
>>>>> >
>>>>> > Also there's a discord server for scons help if you'd like to ask
>>>>> > questions/get help there.
>>>>> > https://discord.gg/bXVpWAy <https://discord.gg/bXVpWAy>
>>>>> >
>>>>> > Hope that helps!
>>>>> > -Bill
>>>>>
>>>>> For inspiration, the mslink tool does this (as does the qt tool) - see
>>>>> the somewhat messy SCons/Tool/mslink.py.
>>>>>
>>>>> Meanwhile, while many tools use add_emitter, the code for add_emitter
>>>>> itself includes this comment:
>>>>>
>>>>>          This assumes that emitter has been initialized with an
>>>>>          appropriate dictionary type, and will throw a TypeError if
>>>>>          not, so the caller is responsible for knowing that this is an
>>>>>          appropriate method to call for the Builder in question.
>>>>>
>>>>> >              env["BUILDERS"]["Program"].add_emitter(
>>>>> >                  suffix = ".map",
>>>>> >                  emitter = map_emitter)
>>>>> >
>>>>> >     But it throws an exception:
>>>>> >
>>>>> >     TypeError: 'EmitterProxy' object does not support item assignment
>>>>>
>>>>> So I guess "expected"? although pretty awkward....
>>>>>
>>>>> _______________________________________________
>>>>> Scons-users mailing list
>>>>> Scons-users at scons.org
>>>>> https://pairlist4.pair.net/mailman/listinfo/scons-users
>>>>>
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