Re: [RFC PATCH 0/3] single-binary: make QAPI generated files common

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

On 24/4/25 20:33, Pierrick Bouvier wrote:

> QAPI
> ====
> 
> QAPI generated files contain conditional clauses to define various structures,
> enums, and commands only for specific targets. This forces files to be
> compiled for every target. What we try to do here is to build them only once
> instead.
> 
> In the past, we identied that the best approach to solve this is to expose code
> for all targets (thus removing all #if clauses), and stub missing
> symbols for concerned targets.
> 
> This series build QAPI generated code once, by removing all TARGET_{arch} and
> CONFIG_KVM clauses. What it does *not* at the moment is:
> - prevent target specific commands to be visible for all targets
>    (see TODO comment on patch 2 explaining how to address this)

+   # "#if TARGET_S390X && CONFIG_KVM" will become:
+   # "if (target_s390x() || kvm_enabled()) {"

I like it.

> - nothing was done to hide all this from generated documentation
> 
>  From what I understood, the only thing that matters is to limit qmp commands
> visible. Exposing enums, structure, or events is not a problem, since they
> won't be used/triggered for non concerned targets. Please correct me if this is
> wrong, and if there are unexpected consequences for libvirt or other consumers.

What about function name clashes? I.e.:

389 ##
390 # @query-cpu-definitions:
391 #
392 # Return a list of supported virtual CPU definitions
393 #
394 # Returns: a list of CpuDefinitionInfo
395 #
396 # Since: 1.2
397 ##
398 { 'command': 'query-cpu-definitions', 'returns': ['CpuDefinitionInfo'],
399   'if': { 'any': [ 'TARGET_PPC',
400                    'TARGET_ARM',
401                    'TARGET_I386',
402                    'TARGET_S390X',
403                    'TARGET_MIPS',
404                    'TARGET_LOONGARCH64',
405                    'TARGET_RISCV' ] } }

$ git grep qmp.query.cpu.definitions
target/arm/arm-qmp-cmds.c:238:CpuDefinitionInfoList 
*qmp_query_cpu_definitions(Error **errp)
target/i386/cpu.c:6418:CpuDefinitionInfoList 
*qmp_query_cpu_definitions(Error **errp)
target/loongarch/loongarch-qmp-cmds.c:30:CpuDefinitionInfoList 
*qmp_query_cpu_definitions(Error **errp)
target/mips/system/mips-qmp-cmds.c:28:CpuDefinitionInfoList 
*qmp_query_cpu_definitions(Error **errp)
target/ppc/ppc-qmp-cmds.c:192:CpuDefinitionInfoList 
*qmp_query_cpu_definitions(Error **errp)
target/riscv/riscv-qmp-cmds.c:56:CpuDefinitionInfoList 
*qmp_query_cpu_definitions(Error **errp)
target/s390x/cpu_models_system.c:85:CpuDefinitionInfoList 
*qmp_query_cpu_definitions(Error **errp)

Prepend target name to these functions and dispatch generated code?