[m-rev.] for review: fix util/mfiltercc on Windows

[Julien Fischer]

Hi Sebastian,

On Tue, 7 Apr 2015, Sebastian Godelet wrote:

> While trying to figure out why util/mfiltercc is not filtering that
> gcc `used but undefined' messages on Windows using either cmd.exe or
> the msys shell, I noticed that command redirection is handled
> differently on the win32 platform.
> So just removing the use_win32 specific code in compiler/module_cmds.m
> and building the compiler itself and all other Mercury programs I did
> not notice any observable difference besides the correct filtering of
> that gcc warning.

My only worry about that is the different support for Windows may have
been required for older versions of Windows.  What version were you
using?

> --
>
> fix util/mfiltercc on Windows
>
> Remove Windows specific error redirection handling to enable the mfiltercc 
> functionality.
>
> compiler/module_cmds.m:
>    see above.
>
> --
>
> diff --git a/compiler/module_cmds.m b/compiler/module_cmds.m
> index e0c7770..03c3219 100644
> --- a/compiler/module_cmds.m
> +++ b/compiler/module_cmds.m
> @@ -568,10 +568,6 @@ invoke_system_command_maybe_filter_output(Globals, 
> ErrorStream, Verbosity,
>         % XXX can't use Bourne shell syntax to redirect on .NET
>         % XXX the output will go to the wrong place!
>         CommandRedirected = Command
> -    ; use_win32 ->
> -        % On windows we can't in general redirect standard error in the
> -        % shell.
> -        CommandRedirected = Command ++ " > " ++ TmpFile
>     ;
>         CommandRedirected =
>             string.append_list([Command, " > ", TmpFile, " 2>&1"])
> @@ -608,19 +604,14 @@ invoke_system_command_maybe_filter_output(Globals, 
> ErrorStream, Verbosity,
>         io.make_temp(ProcessedTmpFile, !IO),
>
>         % XXX we should get rid of use_win32
> -        ( use_win32 ->
> +        (
> +            use_win32,
>             get_system_env_type(Globals, SystemEnvType),
> -            ( SystemEnvType = env_type_powershell ->
> -                ProcessOutputRedirected = string.append_list(
> -                    ["Get-Content ", TmpFile, " | ", ProcessOutput,
> -                        " > ", ProcessedTmpFile, " 2>&1"])
> -            ;
> -                % On windows we can't in general redirect standard
> -                % error in the shell.
> -                ProcessOutputRedirected = string.append_list(
> -                    [ProcessOutput, " < ", TmpFile, " > ",
> -                        ProcessedTmpFile])
> -            )
> +            SystemEnvType = env_type_powershell
> +        ->
> +            ProcessOutputRedirected = string.append_list(
> +                ["Get-Content ", TmpFile, " | ", ProcessOutput,
> +                    " > ", ProcessedTmpFile, " 2>&1"])

A better solution here would be to avoid the use of the use_win32/0 predicate
at all, by just switching on the system env-type.  (We should get rid
of the use_win32/0 predicate.)

Cheers,
Julien.