Cheng Shao pushed to branch wip/remove-legacy-define-in-foreign-stub at Glasgow Haskell Compiler / GHC

Commits:

• 05e25647
  by Cheng Shao at 2025-12-10T12:27:13+01:00

  compiler: remove unused CPP code in foreign stub
  
  This patch removes unused CPP code in the generated foreign stub:
  
  - `#define IN_STG_CODE 0` is not needed, since `Rts.h` already
    includes this definition
  - The `if defined(__cplusplus)` code paths are not needed in the `.c`
    file, since we don't generate C++ stubs and don't include C++
    headers in our stubs. But it still needs to be present in the `.h`
    header since it might be later included into C++ source files.
  

1 changed file:

• compiler/GHC/Driver/CodeOutput.hs

Changes:

         stub_c_file_exists

            <- outputForeignStubs_help stub_c stub_c_output_w

-                ("#define IN_STG_CODE 0\n" ++

-                 "#include <Rts.h>\n" ++

-                 rts_includes ++

-                 ffi_includes ++

-                 cplusplus_hdr)

-                 cplusplus_ftr

-           -- We're adding the default hc_header to the stub file, but this

-           -- isn't really HC code, so we need to define IN_STG_CODE==0 to

-           -- avoid the register variables etc. being enabled.

+                (rts_includes ++

+                 ffi_includes) ""

         return (stub_h_file_exists, if stub_c_file_exists

                                        then Just stub_c