[PATCH] D22370: Respect LLVM_HOST_TRIPLE when manually specified

[Luke Drummond via llvm-commits]

ldrumm added a comment.

In https://reviews.llvm.org/D22370#485676, @beanz wrote:

> Supporting specifying the triple manually is a completely separate issue from the bug you encountered. I'd prefer to make target detection for windows work correctly and reliably so that we don't need to support setting `LLVM_HOST_TRIPLE` manually. Other than the bugs in get_host_triple, is there a reason you feel the need to set the host triple manually?


They are separate issues, I agree, but this kills two birds with one stone, as it fixes the lldb-server cross-compilation issue on win32 *and* enables people to specify the triple manually in the event it is required, while AFAICS not introducing any semantic changes unless the triple is manually specified.

> You are right about using `CMAKE_CL_64`, we should instead use `CMAKE_SIZEOF_VOID_P`. So something more like:

> 

>   diff --git a/cmake/modules/GetHostTriple.cmake b/cmake/modules/GetHostTriple.cmake

>   index 5de710c..f8c7bf1 100644

>   --- a/cmake/modules/GetHostTriple.cmake

>   +++ b/cmake/modules/GetHostTriple.cmake

>   @@ -2,18 +2,18 @@

>    # Invokes config.guess

>    

>    function( get_host_triple var )

>   -  if( MSVC )

>   -    if( CMAKE_CL_64 )

>   -      set( value "x86_64-pc-win32" )

>   -    else()

>   -      set( value "i686-pc-win32" )

>   -    endif()

>   -  elseif( MINGW AND NOT MSYS )

>   +  if( MINGW AND NOT MSYS )

>        if( CMAKE_SIZEOF_VOID_P EQUAL 8 )

>          set( value "x86_64-w64-mingw32" )

>        else()

>          set( value "i686-pc-mingw32" )

>        endif()

>   +  elseif( CMAKE_HOST_WIN32 )

>   +    if( CMAKE_SIZEOF_VOID_P EQUAL 8 )

>   +      set( value "x86_64-pc-win32" )

>   +    else()

>   +      set( value "i686-pc-win32" )

>   +    endif()

>      else( MSVC )

>        set(config_guess ${LLVM_MAIN_SRC_DIR}/cmake/config.guess)

>        execute_process(COMMAND sh ${config_guess}

> 


I'm afraid this won't work. As Tamas mentioned, we're not trying to detect windows; we're trying to detect the triple of the host the lldb-server is going to run on. The triple will need to be arm32-linux-unknown-android or similar. This does is the exact opposite of what we're trying to achieve, and unconditionally sets a win32 triple regardless of the cross compiler.


Repository:
  rL LLVM

https://reviews.llvm.org/D22370