Split psa_switch.h into two files

[mihaibudiu]

Signed-off-by: Mihai Budiu mbudiu@vmware.com

This is not really the desired final result, but it is a test that the bmv2-specific parts can be separated from the psa-specific parts of the code. The psa-specific parts should be reused by multiple backends. Probably we should move them to some architecture/ directory.

@osinstom can you see whether this structure removes all bmv2 dependencies from the ebpf backend (except psaProgramStructure.h)?

[mihaibudiu]

Today the p4c code structure does not have separate directories for architectures (models?) and targets.
The code specific to an architecture essentially validates that the code is written for the correct architecture and extracts all relevant information for code-generation. Code-generation is target-specific, and should only read the extracted information.

[osinstom]

@mbudiu-vmw thanks for investigating this. I'm getting exactly the same error as on CI: https://github.com/p4lang/p4c/runs/5654254563?check_suite_focus=true.

/home/dev/workspace/p4c-1/backends/bmv2/psa_switch/psaProgramStructure.cpp: In member function ‘virtual bool BMV2::InspectPsaProgram::preorder(const IR::Parameter*)’:
/home/dev/workspace/p4c-1/backends/bmv2/psa_switch/psaProgramStructure.cpp:193:9: error: ‘PsaSwitchExpressionConverter’ has not been declared
  193 |     if (PsaSwitchExpressionConverter::isStandardMetadata(ptName)) {
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~

[rst0git]

@mbudiu-vmw thanks for investigating this. I'm getting exactly the same error as on CI: https://github.com/p4lang/p4c/runs/5654254563?check_suite_focus=true.

/home/dev/workspace/p4c-1/backends/bmv2/psa_switch/psaProgramStructure.cpp: In member function ‘virtual bool BMV2::InspectPsaProgram::preorder(const IR::Parameter*)’:
/home/dev/workspace/p4c-1/backends/bmv2/psa_switch/psaProgramStructure.cpp:193:9: error: ‘PsaSwitchExpressionConverter’ has not been declared
  193 |     if (PsaSwitchExpressionConverter::isStandardMetadata(ptName)) {
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~

isStandardMetadata() is defined in psaSwitch.h.

[rst0git]

The psa-specific parts should be reused by multiple backends. Probably we should move them to some architecture/ directory.

Sounds good to me.

[osinstom]

@mbudiu-vmw thanks for investigating this. I'm getting exactly the same error as on CI: https://github.com/p4lang/p4c/runs/5654254563?check_suite_focus=true.

/home/dev/workspace/p4c-1/backends/bmv2/psa_switch/psaProgramStructure.cpp: In member function ‘virtual bool BMV2::InspectPsaProgram::preorder(const IR::Parameter*)’:
/home/dev/workspace/p4c-1/backends/bmv2/psa_switch/psaProgramStructure.cpp:193:9: error: ‘PsaSwitchExpressionConverter’ has not been declared
  193 |     if (PsaSwitchExpressionConverter::isStandardMetadata(ptName)) {
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~

isStandardMetadata() is defined in psaSwitch.h.

Right. So, the minimal set of dependencies I've found out to (almost) work is:

  ../bmv2/common/programStructure.cpp
  ../bmv2/psa_switch/psaProgramStructure.cpp
  
  ../bmv2/common/programStructure.h
  ../bmv2/psa_switch/psaSwitch.h
  ../bmv2/psa_switch/psaProgramStructure.h

However, I'm facing the following error:

CMakeFiles/p4c-ebpf.dir/unified_p4c_ebpf_srcs_3.cpp.o:unified_p4c_ebpf_srcs_3.cpp:function EBPF::PSASwitchBackend::convert(IR::ToplevelBlock const*): error: undefined reference to 'VTT for BMV2::ParsePsaArchitecture'
CMakeFiles/p4c-ebpf.dir/unified_p4c_ebpf_srcs_3.cpp.o:unified_p4c_ebpf_srcs_3.cpp:function EBPF::PSASwitchBackend::convert(IR::ToplevelBlock const*): error: undefined reference to 'VTT for BMV2::ParsePsaArchitecture'
CMakeFiles/p4c-ebpf.dir/unified_p4c_ebpf_srcs_3.cpp.o:unified_p4c_ebpf_srcs_3.cpp:function EBPF::PSASwitchBackend::convert(IR::ToplevelBlock const*): error: undefined reference to 'vtable for BMV2::ParsePsaArchitecture'
/usr/bin/ld.gold: the vtable symbol may be undefined because the class is missing its key function

I assume it's because preorder methods for ParsePsaArchitecture are still defined in psaSwitch.cpp: https://github.com/mbudiu-vmw/p4c-clone/blob/split-psa/backends/bmv2/psa_switch/psaSwitch.cpp#L251. If I include psaSwitch.cpp I'm getting an explosion of missing dependencies.

[mihaibudiu]

Hopefully my new commit has fixed the missing class problem.

[osinstom]

@mbudiu-vmw I confirm that PSA-eBPF compiles successfully with the set of dependencies that I've pasted above. Feel free to merge this, so that I can rebase and apply these modifications to #3139.

[mihaibudiu]

Will do once CI tests are finished

[rst0git]

LGTM