make: .exe handling breaks kernel cross-compile

make: .exe handling breaks kernel cross-compile

[Yaakov (Cygwin/X)]

I can confirm that this previously reported bug in make .exe handling 
still affects the cross-compile of the Linux kernel:

http://cygwin.com/ml/cygwin/2009-11/msg00935.html


Yaakov

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Re: make: .exe handling breaks kernel cross-compile

[Christopher Faylor]

On Sun, Jun 10, 2012 at 01:06:18PM -0500, Yaakov (Cygwin/X) wrote:
>I can confirm that this previously reported bug in make .exe handling 
>still affects the cross-compile of the Linux kernel:
>
>http://cygwin.com/ml/cygwin/2009-11/msg00935.html

Without diving into the depths of the linux makefiles, this doesn't seem
like a bug.  gcc creates .exe files.  The makefile isn't expecting to
create one and, so, gets confused.  Makefiles which expect .exe
extensions usually use the EXEEXT variable for just this purpose.
Linux's makefile doesn't do that for probably obvious reasons.

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Re: make: .exe handling breaks kernel cross-compile

[Yaakov (Cygwin/X)]

On 2012-06-10 13:29, Christopher Faylor wrote:
> On Sun, Jun 10, 2012 at 01:06:18PM -0500, Yaakov (Cygwin/X) wrote:
>> I can confirm that this previously reported bug in make .exe handling
>> still affects the cross-compile of the Linux kernel:
>>
>> http://cygwin.com/ml/cygwin/2009-11/msg00935.html
>
> Without diving into the depths of the linux makefiles, this doesn't seem
> like a bug.  gcc creates .exe files.  The makefile isn't expecting to
> create one and, so, gets confused.  Makefiles which expect .exe
> extensions usually use the EXEEXT variable for just this purpose.
> Linux's makefile doesn't do that for probably obvious reasons.

While our make won't connect a dep on "foo" to a foo.exe rule (which can 
occur in automake-generated Makefiles with custom rules), it does see 
foo.exe fulfilling a dep on "foo" if it is already present:

$ cat Makefile
all: bar
bar: foo
	touch bar.exe
clean:
	rm -f bar.exe foo.exe

$ touch foo.exe
$ make
touch bar.exe
$ make clean
rm -f bar.exe foo.exe

The problem here is the kernel uses VPATH -- scripts/pnmtologo(.exe) is 
not relative to drivers/video/logo, but rather to $(O) -- and somehow 
with VPATH the .exe magic doesn't happen:

$ cat Makefile
VPATH = $(PWD)/build

all: bar
bar: foo
	touch bar.exe

$ mkdir -p build
$ touch build/foo.exe
$ make
make: *** No rule to make target `foo', needed by `bar'.  Stop.

So foo.exe fulfills foo, but not with VPATH.  Isn't that a bug?


Yaakov

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Re: make: .exe handling breaks kernel cross-compile

[Christopher Faylor]

On Sun, Jun 10, 2012 at 03:57:33PM -0500, Yaakov (Cygwin/X) wrote:
>On 2012-06-10 13:29, Christopher Faylor wrote:
>> On Sun, Jun 10, 2012 at 01:06:18PM -0500, Yaakov (Cygwin/X) wrote:
>>> I can confirm that this previously reported bug in make .exe handling
>>> still affects the cross-compile of the Linux kernel:
>>>
>>> http://cygwin.com/ml/cygwin/2009-11/msg00935.html
>>
>> Without diving into the depths of the linux makefiles, this doesn't seem
>> like a bug.  gcc creates .exe files.  The makefile isn't expecting to
>> create one and, so, gets confused.  Makefiles which expect .exe
>> extensions usually use the EXEEXT variable for just this purpose.
>> Linux's makefile doesn't do that for probably obvious reasons.
>
>While our make won't connect a dep on "foo" to a foo.exe rule (which can 
>occur in automake-generated Makefiles with custom rules), it does see 
>foo.exe fulfilling a dep on "foo" if it is already present:
>
>$ cat Makefile
>all: bar
>bar: foo
>	touch bar.exe
>clean:
>	rm -f bar.exe foo.exe
>
>$ touch foo.exe
>$ make
>touch bar.exe
>$ make clean
>rm -f bar.exe foo.exe
>
>The problem here is the kernel uses VPATH -- scripts/pnmtologo(.exe) is 
>not relative to drivers/video/logo, but rather to $(O) -- and somehow 
>with VPATH the .exe magic doesn't happen:
>
>$ cat Makefile
>VPATH = $(PWD)/build
>
>all: bar
>bar: foo
>	touch bar.exe
>
>$ mkdir -p build
>$ touch build/foo.exe
>$ make
>make: *** No rule to make target `foo', needed by `bar'.  Stop.
>
>So foo.exe fulfills foo, but not with VPATH.  Isn't that a bug?

If there is a bug it is with make ever equating foo.exe with foo.  It's
undoubtedly happening because of Cygwin's attempts at transparency.

I'm not kidding about EXEEXT.  Surely you know about this from having
maintained cygport.

cgf

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Re: make: .exe handling breaks kernel cross-compile

[Yaakov (Cygwin/X)]

On 2012-06-10 23:26, Christopher Faylor wrote:
> If there is a bug it is with make ever equating foo.exe with foo.  It's
> undoubtedly happening because of Cygwin's attempts at transparency.
>
> I'm not kidding about EXEEXT.  Surely you know about this from having
> maintained cygport.

Am I ever, but I suspect *you* know that incorporating EXEEXT into the 
Linux kernel buildsystem will likely never be accepted upstream.

That being said, I do have another patch which might have a chance, so 
the last hurdle from our side is in regex, per my previous thread.


Yaakov


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Re: make: .exe handling breaks kernel cross-compile

[Christopher Faylor]

On Mon, Jun 11, 2012 at 01:04:22AM -0500, Yaakov (Cygwin/X) wrote:
>>
>On 2012-06-10 23:26, Christopher Faylor wrote:
>> If there is a bug it is with make ever equating foo.exe with foo.  It's
>> undoubtedly happening because of Cygwin's attempts at transparency.
>>
>> I'm not kidding about EXEEXT.  Surely you know about this from having
>> maintained cygport.
>
>Am I ever, but I suspect *you* know that incorporating EXEEXT into the 
>Linux kernel buildsystem will likely never be accepted upstream.

>>On 2012-06-10 14:29, Christopher Faylor wrote:
>>>Makefiles which expect .exe extensions usually use the EXEEXT variable
>>>for just this purpose.  Linux's makefile doesn't do that for probably
>>>obvious reasons.


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