llvm dev - Mar 2005 - [LLVMdev] GCC assembler rejects native code generated by LLVM

I successfully compiled CVS HEAD yesterday on my win32 machine using
Visual C++ Express (2005). I also have Mingw tools installed. I wrote
a simple hello world application and generated native assembly code
using llvm. When I tried to feed the code into GCC, it rejected it
with "junk at the end of line" error messages. Shouldn't GCC be
able
to assemble this code? I realize win32 port isn't complete but I was
under the impression that this should work.

Thanks.

On Mon, 7 Mar 2005, Vyacheslav Akhmechet wrote:
> I successfully compiled CVS HEAD yesterday on my win32 machine using
> Visual C++ Express (2005). I also have Mingw tools installed. I wrote
> a simple hello world application and generated native assembly code
> using llvm. When I tried to feed the code into GCC, it rejected it
> with "junk at the end of line" error messages. Shouldn't GCC
be able
> to assemble this code? I realize win32 port isn't complete but I was
> under the impression that this should work.
I'm not sure what the issue is, but if you send in the exact .s file 
produced and the errors you're getting, we can fix it. :)

-Chris

-- 
http://nondot.org/sabre/
http://llvm.cs.uiuc.edu/

I'm at work so I don't have exact details at the moment. I'll send
the
.s file and the errors tonight.

Thanks for the quick reply!

On Mon, 7 Mar 2005 10:36:10 -0600 (CST), Chris Lattner <sabre at
nondot.org> wrote:
> On Mon, 7 Mar 2005, Vyacheslav Akhmechet wrote:
> > I successfully compiled CVS HEAD yesterday on my win32 machine using
> > Visual C++ Express (2005). I also have Mingw tools installed. I wrote
> > a simple hello world application and generated native assembly code
> > using llvm. When I tried to feed the code into GCC, it rejected it
> > with "junk at the end of line" error messages. Shouldn't
GCC be able
> > to assemble this code? I realize win32 port isn't complete but I
was
> > under the impression that this should work.
> 
> I'm not sure what the issue is, but if you send in the exact .s file
> produced and the errors you're getting, we can fix it. :)
> 
> -Chris
> 
> --
> http://nondot.org/sabre/
> http://llvm.cs.uiuc.edu/
>

I'm confused.  My understanding is that Visual C++ Express does not 
include Visual Studio, which is required to build LLVM.  Anyway, 
assembly code generation is not yet supported using the Microsoft tool 
chain (as documented in the Getting Started with VS page), and when it 
is it will be with NASMW and not GCC.  Not that any of this explains the 
"junk at the end of line" you got.

Vyacheslav Akhmechet wrote:
>I successfully compiled CVS HEAD yesterday on my win32 machine using
>Visual C++ Express (2005). I also have Mingw tools installed. I wrote
>a simple hello world application and generated native assembly code
>using llvm. When I tried to feed the code into GCC, it rejected it
>with "junk at the end of line" error messages. Shouldn't GCC
be able
>to assemble this code? I realize win32 port isn't complete but I was
>under the impression that this should work.
>
>Thanks.
>
>_______________________________________________
>LLVM Developers mailing list
>LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
>http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev
>
>
>  
>

> I'm confused.  My understanding is that Visual C++ Express does not
> include Visual Studio, which is required to build LLVM.
Well, Visual C++ Express is a cut down version of Visual Studio. I'm
not sure about exact differences between editions but Visual C++
Express does read the .sln files and comes with an excellent C++
compiler. I didn't encounter any problems building llvm or running
various tools.
> Anyway,
> assembly code generation is not yet supported using the Microsoft tool
> chain (as documented in the Getting Started with VS page)
I've seen that document. It suggests that one cannot assemble native
executables using MS tools because they don't come with an assembler.
Another document (don't remember which one, exactly) says native code
generation is supported on Windows using Mingw tools. This is exactly
what I'm trying to do: assemble an executable using Mingw. I don't see
why it should matter whether llvm tools are built using gcc or MSVC,
the generated assembly code should be the same, shouldn't it?

Ok, I got home so I have more details. Here's the sample C program:
----------------- C program ---------------
   #include <stdio.h>
   int main() {
     printf("hello world\n");
     return 0;
   }
------------- end C program -------------

This is compiled using llvm online demo into the following llvm code
(target removed):
----------------- LLVM code --------------
deplibs = [ "stdc++", "c", "crtend" ]
%.str_1 = internal constant [13 x sbyte] c"hello world\0A\00"; <[13
x
sbyte]*> [#uses=1]

implementation   ; Functions:

declare int %printf(sbyte*, ...)

int %main() {
entry:
call void %__main( )
%tmp.0 = call int (sbyte*, ...)* %printf( sbyte* getelementptr ([13 x
sbyte]* %.str_1, int 0, int 0) ); <int> [#uses=0]
ret int 0
}

declare void %__main()
------------- End LLVM code -----------

which in turn produces the following assembly code:

------------- Assembly code -------------
	.text
	.align	16
	.globl	main
	.type	main, @function
main:
	subl $12, %esp
	fnstcw 10(%esp)
	movb $2, 11(%esp)
	fldcw 10(%esp)
	call __main
	movl $l1__2E_str_1, %eax
	movl %eax, (%esp)
	call printf
	movl $0, %eax
	#IMPLICIT_USE
	addl $12, %esp
	ret


	.data
	.align	1
	.type l1__2E_str_1, at object
	.size l1__2E_str_1,13
l1__2E_str_1:				# [13 x sbyte]* %.str_1 =  c"hello world\0A\00"
	.ascii	"hello world\n\000"
---------- End assembly code ----------

When I try to assemble the above code using
gcc hello.c.s -o hello.exe
I get the following errors:

hello.c.s: Assembler messages:
hello.c.s:6: Warning: .type pseudo-op used outside of .def/.endef ignored.
hello.c.s:6: Error: junk at end of line, first unrecognized character is `m'
hello.c.s:24: Warning: .type pseudo-op used outside of .def/.endef ignored.
hello.c.s:24: Error: junk at end of line, first unrecognized character is
`l'
hello.c.s:25: Warning: .size pseudo-op used outside of .def/.endef ignored.
hello.c.s:25: Error: junk at end of line, first unrecognized character is
`l'

Sorry for the long email. I attach all relevant files for clarity.
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Vyacheslav,

This is the same problem that I had with Cygwin .. nearly identical.
The issue was documented in PR492 if you want some background. I'm
currently trying to dig up what I did to fix this in December for Cygwin
and see if I can apply the same change for mingw.

Reid.

On Mon, 2005-03-07 at 16:39, Vyacheslav Akhmechet wrote:
> Ok, I got home so I have more details. Here's the sample C program:
> ----------------- C program ---------------
>    #include <stdio.h>
>    int main() {
>      printf("hello world\n");
>      return 0;
>    }
> ------------- end C program -------------
> 
> This is compiled using llvm online demo into the following llvm code
> (target removed):
> ----------------- LLVM code --------------
> deplibs = [ "stdc++", "c", "crtend" ]
> %.str_1 = internal constant [13 x sbyte] c"hello world\0A\00";
<[13 x
> sbyte]*> [#uses=1]
> 
> implementation   ; Functions:
> 
> declare int %printf(sbyte*, ...)
> 
> int %main() {
> entry:
> call void %__main( )
> %tmp.0 = call int (sbyte*, ...)* %printf( sbyte* getelementptr ([13 x
> sbyte]* %.str_1, int 0, int 0) ); <int> [#uses=0]
> ret int 0
> }
> 
> declare void %__main()
> ------------- End LLVM code -----------
> 
> which in turn produces the following assembly code:
> 
> ------------- Assembly code -------------
> 	.text
> 	.align	16
> 	.globl	main
> 	.type	main, @function
> main:
> 	subl $12, %esp
> 	fnstcw 10(%esp)
> 	movb $2, 11(%esp)
> 	fldcw 10(%esp)
> 	call __main
> 	movl $l1__2E_str_1, %eax
> 	movl %eax, (%esp)
> 	call printf
> 	movl $0, %eax
> 	#IMPLICIT_USE
> 	addl $12, %esp
> 	ret
> 
> 
> 	.data
> 	.align	1
> 	.type l1__2E_str_1, at object
> 	.size l1__2E_str_1,13
> l1__2E_str_1:				# [13 x sbyte]* %.str_1 =  c"hello world\0A\00"
> 	.ascii	"hello world\n\000"
> ---------- End assembly code ----------
> 
> When I try to assemble the above code using
> gcc hello.c.s -o hello.exe
> I get the following errors:
> 
> hello.c.s: Assembler messages:
> hello.c.s:6: Warning: .type pseudo-op used outside of .def/.endef ignored.
> hello.c.s:6: Error: junk at end of line, first unrecognized character is
`m'
> hello.c.s:24: Warning: .type pseudo-op used outside of .def/.endef ignored.
> hello.c.s:24: Error: junk at end of line, first unrecognized character is
`l'
> hello.c.s:25: Warning: .size pseudo-op used outside of .def/.endef ignored.
> hello.c.s:25: Error: junk at end of line, first unrecognized character is
`l'
> 
> Sorry for the long email. I attach all relevant files for clarity.
> 
> ______________________________________________________________________
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev
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Vyacheslav,

I've tracked down the change and I have a fix for you to test. The
attached patch should be applied to the CVS head (version 1.132) of
X86AsmPrinter.cpp in llvm/lib/Target/X86. The patch just includes MINGW
targets in the same set of choices that it makes for Cygwin. Could you
please try the patch and let me know if it solves your problem? If it
does, I'll commit the patch.

Thanks,

Reid.


On Mon, 2005-03-07 at 16:39, Vyacheslav Akhmechet wrote:
> Ok, I got home so I have more details. Here's the sample C program:
> ----------------- C program ---------------
>    #include <stdio.h>
>    int main() {
>      printf("hello world\n");
>      return 0;
>    }
> ------------- end C program -------------
> 
> This is compiled using llvm online demo into the following llvm code
> (target removed):
> ----------------- LLVM code --------------
> deplibs = [ "stdc++", "c", "crtend" ]
> %.str_1 = internal constant [13 x sbyte] c"hello world\0A\00";
<[13 x
> sbyte]*> [#uses=1]
> 
> implementation   ; Functions:
> 
> declare int %printf(sbyte*, ...)
> 
> int %main() {
> entry:
> call void %__main( )
> %tmp.0 = call int (sbyte*, ...)* %printf( sbyte* getelementptr ([13 x
> sbyte]* %.str_1, int 0, int 0) ); <int> [#uses=0]
> ret int 0
> }
> 
> declare void %__main()
> ------------- End LLVM code -----------
> 
> which in turn produces the following assembly code:
> 
> ------------- Assembly code -------------
> 	.text
> 	.align	16
> 	.globl	main
> 	.type	main, @function
> main:
> 	subl $12, %esp
> 	fnstcw 10(%esp)
> 	movb $2, 11(%esp)
> 	fldcw 10(%esp)
> 	call __main
> 	movl $l1__2E_str_1, %eax
> 	movl %eax, (%esp)
> 	call printf
> 	movl $0, %eax
> 	#IMPLICIT_USE
> 	addl $12, %esp
> 	ret
> 
> 
> 	.data
> 	.align	1
> 	.type l1__2E_str_1, at object
> 	.size l1__2E_str_1,13
> l1__2E_str_1:				# [13 x sbyte]* %.str_1 =  c"hello world\0A\00"
> 	.ascii	"hello world\n\000"
> ---------- End assembly code ----------
> 
> When I try to assemble the above code using
> gcc hello.c.s -o hello.exe
> I get the following errors:
> 
> hello.c.s: Assembler messages:
> hello.c.s:6: Warning: .type pseudo-op used outside of .def/.endef ignored.
> hello.c.s:6: Error: junk at end of line, first unrecognized character is
`m'
> hello.c.s:24: Warning: .type pseudo-op used outside of .def/.endef ignored.
> hello.c.s:24: Error: junk at end of line, first unrecognized character is
`l'
> hello.c.s:25: Warning: .size pseudo-op used outside of .def/.endef ignored.
> hello.c.s:25: Error: junk at end of line, first unrecognized character is
`l'
> 
> Sorry for the long email. I attach all relevant files for clarity.
> 
> ______________________________________________________________________
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev
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Index: X86AsmPrinter.cpp
==================================================================RCS file:
/var/cvs/llvm/llvm/lib/Target/X86/X86AsmPrinter.cpp,v
retrieving revision 1.132
diff -r1.132 X86AsmPrinter.cpp
89c89
< #ifdef __CYGWIN__
---
> #if defined(__CYGWIN__) || defined(__MINGW32__)
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