Add mcTVM MACA FFI patch guards

[ghangz]

Summary

• This change adds guard logic around MACA FFI patch handling so repeated configure or partial dependency states fail earlier with clearer behavior.
• The change is limited to MACA build discovery or guarded setup logic and keeps existing default behavior compatible.
• Main files: cmake/modules/MACA.cmake

Validation

• Verified on Gitee.AI MetaX GPU resources in the mcTVM TileLang/MACA TVM build batch, 6/6 PASS.
• Branch validation command: CMake configure and mxcc compile smoke validation in the MACA TVM build image.
• Pull request text is ASCII-only to avoid encoding issues on web forms and API clients.

Review notes

• Source branch: ghangz:mengz/mctvm-maca-guard-ffi-patches
• Target branch: MetaX-MACA/mcTVM:dev
• Maintainers can modify this branch if follow-up adjustments are needed.

[gemini-code-assist]

Code Review

This pull request adds existence checks (if(EXISTS)) before reading and modifying several third-party files in cmake/modules/MACA.cmake. The reviewer feedback highlights that if any of the string(REPLACE) operations fail to find their target strings, CMake will still write the unmodified contents back to the files on every configure run. This updates their modification times and triggers unnecessary rebuilds. The reviewer suggests adding a check to ensure NEW_CONTENTS is different from FILE_CONTENTS before performing the write operation.

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[gemini-code-assist]

If the string(REPLACE) operation fails to find the target string (e.g., due to upstream changes in the file structure), NEW_CONTENTS will be identical to FILE_CONTENTS. Since NOT FILE_CONTENTS MATCHES ".*kDLMACA.*" remains true, CMake will write to the file on every single configure run. This updates the file's modification time and triggers unnecessary rebuilds of dependent targets.

To prevent this, only write the file if NEW_CONTENTS is actually different from FILE_CONTENTS.

if(EXISTS "${dlpack_header}")
  file(READ "${dlpack_header}" FILE_CONTENTS)
  if(NOT FILE_CONTENTS MATCHES ".*kDLMACA.*")
    string(REPLACE "} DLDeviceType;" "  kDLMACA = 19,\n  kDLMACAHost = 20,\n} DLDeviceType;" NEW_CONTENTS "${FILE_CONTENTS}")
    if(NOT "${NEW_CONTENTS}" STREQUAL "${FILE_CONTENTS}")
      file(WRITE "${dlpack_header}" "${NEW_CONTENTS}")
    endif()
  endif()
endif()

[gemini-code-assist]

If the string(REPLACE) operation fails to find the target string, NEW_CONTENTS will be identical to FILE_CONTENTS. Since NOT FILE_CONTENTS MATCHES ".*kDLMACA.*" remains true, CMake will write to the file on every single configure run. This updates the file's modification time and triggers unnecessary rebuilds of dependent targets.

To prevent this, only write the file if NEW_CONTENTS is actually different from FILE_CONTENTS.

if(EXISTS "${ffi_core_pyi}")
  file(READ "${ffi_core_pyi}" FILE_CONTENTS)
  if(NOT FILE_CONTENTS MATCHES ".*kDLMACA.*")
    string(REPLACE "kDLTrn = 17" "kDLTrn = 17\n    kDLMACA = 19\n    kDLMACAHost = 20" NEW_CONTENTS "${FILE_CONTENTS}")
    if(NOT "${NEW_CONTENTS}" STREQUAL "${FILE_CONTENTS}")
      file(WRITE "${ffi_core_pyi}" "${NEW_CONTENTS}")
    endif()
  endif()
endif()

[gemini-code-assist]

If the string(REPLACE) operation fails to find the target string, NEW_CONTENTS will be identical to FILE_CONTENTS. Since NOT FILE_CONTENTS MATCHES ".*kDLMACA.*" remains true, CMake will write to the file on every single configure run. This updates the file's modification time and triggers unnecessary rebuilds of dependent targets.

To prevent this, only write the file if NEW_CONTENTS is actually different from FILE_CONTENTS.

if(EXISTS "${ffi_container_tensor}")
  file(READ "${ffi_container_tensor}" FILE_CONTENTS)
  if(NOT FILE_CONTENTS MATCHES ".*kDLMACA.*")
    string(REPLACE "device.device_type == kDLROCMHost;" "device.device_type == kDLROCMHost ||\n         device.device_type == kDLMACA || device.device_type == kDLMACAHost;" NEW_CONTENTS "${FILE_CONTENTS}")
    if(NOT "${NEW_CONTENTS}" STREQUAL "${FILE_CONTENTS}")
      file(WRITE "${ffi_container_tensor}" "${NEW_CONTENTS}")
    endif()
  endif()
endif()

[gemini-code-assist]

If the string(REPLACE) operation fails to find the target string, NEW_CONTENTS will be identical to FILE_CONTENTS. Since NOT FILE_CONTENTS MATCHES ".*kDLMACA.*" remains true, CMake will write to the file on every single configure run. This updates the file's modification time and triggers unnecessary rebuilds of dependent targets.

To prevent this, only write the file if NEW_CONTENTS is actually different from FILE_CONTENTS.

if(EXISTS "${ffi_cython_base_pxi}")
  file(READ "${ffi_cython_base_pxi}" FILE_CONTENTS)
  if(NOT FILE_CONTENTS MATCHES ".*kDLMACA.*")
    string(REPLACE "kDLTrn = 18" "kDLTrn = 18\n        kDLMACA = 19\n        kDLMACAHost = 20" NEW_CONTENTS "${FILE_CONTENTS}")
    if(NOT "${NEW_CONTENTS}" STREQUAL "${FILE_CONTENTS}")
      file(WRITE "${ffi_cython_base_pxi}" "${NEW_CONTENTS}")
    endif()
  endif()
endif()

[gemini-code-assist]

If the string(REPLACE) operation fails to find the target string, NEW_CONTENTS will be identical to FILE_CONTENTS. Since NOT FILE_CONTENTS MATCHES ".*kDLMACA.*" remains true, CMake will write to the file on every single configure run. This updates the file's modification time and triggers unnecessary rebuilds of dependent targets.

To prevent this, only write the file if NEW_CONTENTS is actually different from FILE_CONTENTS.

if(EXISTS "${ffi_cython_device_pxi}")
  file(READ "${ffi_cython_device_pxi}" FILE_CONTENTS)
  if(NOT FILE_CONTENTS MATCHES ".*kDLMACA.*")
    string(REPLACE "kDLTrn = 17" "kDLTrn = 17\n    kDLMACA = 19\n    kDLMACAHost = 20" NEW_CONTENTS "${FILE_CONTENTS}")
    string(REPLACE "DLDeviceType.kDLTrn: \"trn\"," "DLDeviceType.kDLTrn: \"trn\",\n      DLDeviceType.kDLMACA: \"maca\",\n      DLDeviceType.kDLMACAHost: \"maca_host\"," NEW_CONTENTS "${NEW_CONTENTS}")
    string(REPLACE "\"trn\": DLDeviceType.kDLTrn," "\"trn\": DLDeviceType.kDLTrn,\n        \"maca\": DLDeviceType.kDLMACA," NEW_CONTENTS "${NEW_CONTENTS}")
    if(NOT "${NEW_CONTENTS}" STREQUAL "${FILE_CONTENTS}")
      file(WRITE "${ffi_cython_device_pxi}" "${NEW_CONTENTS}")
    endif()
  endif()
endif()