[lldb] Use add_custom_command for SBLanguages.h

[JDevlieghere]

Use add_custom_command instead of add_custom_target to generate SBLanguages.h.

[llvmbot]

@llvm/pr-subscribers-lldb

Author: Jonas Devlieghere (JDevlieghere)

Changes

Use add_custom_command instead of add_custom_target to generate SBLanguages.h.

---

Full diff: https://github.com/llvm/llvm-project/pull/91254.diff

1 Files Affected:

• (modified) lldb/source/API/CMakeLists.txt (+5-7)

diff --git a/lldb/source/API/CMakeLists.txt b/lldb/source/API/CMakeLists.txt
index a64c0d4a333425..798a92874f13d1 100644
--- a/lldb/source/API/CMakeLists.txt
+++ b/lldb/source/API/CMakeLists.txt
@@ -23,13 +23,13 @@ endif()
 # Target to generate SBLanguages.h from Dwarf.def.
 set(sb_languages_file
   ${CMAKE_CURRENT_BINARY_DIR}/../../include/lldb/API/SBLanguages.h)
-add_custom_target(
-  lldb-sbapi-dwarf-enums
-  "${Python3_EXECUTABLE}"
+add_custom_command(
+  COMMENT "Generating SBLanguages.h from Dwarf.def"
+  COMMAND "${Python3_EXECUTABLE}"
       ${LLDB_SOURCE_DIR}/scripts/generate-sbapi-dwarf-enum.py
       ${LLVM_MAIN_INCLUDE_DIR}/llvm/BinaryFormat/Dwarf.def
       -o ${sb_languages_file}
-  BYPRODUCTS ${sb_languages_file}
+  OUTPUT ${sb_languages_file}
   DEPENDS ${LLVM_MAIN_INCLUDE_DIR}/llvm/BinaryFormat/Dwarf.def
   WORKING_DIRECTORY ${LLVM_LIBRARY_OUTPUT_INTDIR}
 )
@@ -113,9 +113,7 @@ add_lldb_library(liblldb SHARED ${option_framework}
   SystemInitializerFull.cpp
   ${lldb_python_wrapper}
   ${lldb_lua_wrapper}
-
-  DEPENDS
-    lldb-sbapi-dwarf-enums
+  ${sb_languages_file}
 
   LINK_LIBS
     lldbBreakpoint

[bulbazord]

This should work if there is exactly one thing that depends on the output of this custom command. If multiple things start depending on the generated files, you may end up with weird results. See:

https://cmake.org/cmake/help/latest/command/add_custom_command.html

Do not list the output in more than one independent target that may build in parallel or the instances of the rule may conflict. Instead, use the add_custom_target() command to drive the command and make the other targets depend on that one. See the Example: Generating Files for Multiple Targets below.

[JDevlieghere]

Good point. I can't imagine anything needing the SB header that doesn't need the rest of the framework, but if that's the case we go through a custom target.

[labath]

thanks