Re: [Qemu-devel] QEMU build fails with Clang?

[Brad Smith]

On Sat, Jan 05, 2013 at 04:51:01PM +0000, Blue Swirl wrote:
> On Sat, Jan 5, 2013 at 1:48 AM, Brad Smith <address@hidden> wrote:
> > Supposedly QEMU is able to build with Clang and yet trying to do so
> > I am seeing the build fail as follows..
> >
> > Comments?
> 
> Clang does not support this kind of assembly code yet. The attached
> patch avoids this by using 'as' and 'cpp' for .S files, please try. It
> could still fail if the 'as' does not come from binutils.

Could this please use $CC -E instead unless overridden? It just
makes it easier if I only have to override CC and not CPP as well
if using LLVM/Clang or even say another copy of GCC and have it
use the appropriate C preprocessor.

BTW, there are some interesting warnings spit out while compiling
with Clang and most of them look to be legit issues with the code.

QEMU builds and works fine with Clang with this patch applied.

> >
> >
> > gmake[1]: Entering directory `/home/brad/qemu/pc-bios/optionrom'
> > clang -I. -I/home/brad/qemu -I/home/brad/qemu/include 
> > -I/home/brad/qemu/libcacard -Wall -Wstrict-prototypes -Werror 
> > -fomit-frame-pointer -fno-builtin -I/home/brad/qemu   -fno-stack-protector 
> > -MMD -MP -MT multiboot.o -MF ./multiboot.d -Wall -Wstrict-prototypes 
> > -Werror -fomit-frame-pointer -fno-builtin -I/home/brad/qemu   
> > -fno-stack-protector -c -o multiboot.o multiboot.S
> > multiboot.S:31:1: error: unexpected directive .code16
> > .code16; .text; .global _start; _start:; .short 0xaa55; .byte (_end - 
> > _start) / 512; lret; .org 0x18; .short 0; .short _pnph; _pnph: .ascii 
> > "$PnP"; .byte 0x01; .byte ( _pnph_len / 16 ); .short 0x0000; .byte 0x00; 
> > .byte 0x00; .long 0x00000000; .short _manufacturer; .short _product; .long 
> > 0x00000000; .short 0x0000; .short 0x0000; .short _bev; .short 0x0000; 
> > .short 0x0000; .equ _pnph_len, . - _pnph; _bev:; movw %cs, %ax; movw %ax, 
> > %ds;
> > ^
> > multiboot.S:31:8: error: .code16 not supported yet
> > .code16; .text; .global _start; _start:; .short 0xaa55; .byte (_end - 
> > _start) / 512; lret; .org 0x18; .short 0; .short _pnph; _pnph: .ascii 
> > "$PnP"; .byte 0x01; .byte ( _pnph_len / 16 ); .short 0x0000; .byte 0x00; 
> > .byte 0x00; .long 0x00000000; .short _manufacturer; .short _product; .long 
> > 0x00000000; .short 0x0000; .short 0x0000; .short _bev; .short 0x0000; 
> > .short 0x0000; .equ _pnph_len, . - _pnph; _bev:; movw %cs, %ax; movw %ax, 
> > %ds;
> >        ^
> > multiboot.S:71:135: error: unknown directive
> >  read_fw 0x0a; mov %eax, %edi; read_fw 0x0b; mov %eax, %ecx; mov $0x12, 
> > %ax; mov $0x510, %edx; outw %ax, (%dx); mov $0x511, %dx; cld; .dc.b 
> > 0xf3,0x6c
> >                                                                             
> >                                                           ^
> > multiboot.S:102:2: error: unknown directive
> >  .dc.b 0x26,0x67,0x66,0x89,0x4f,0xfc
> >  ^
> > multiboot.S:130:17: error: unexpected token in argument list
> >  data32 lgdt %gs:6
> >                 ^
> > multiboot.S:138:15: error: unknown token in expression
> >  data32 ljmp *%gs:0
> >               ^
> > multiboot.S:152:135: error: unknown directive
> >  read_fw 0x07; mov %eax, %edi; read_fw 0x08; mov %eax, %ecx; mov $0x11, 
> > %ax; mov $0x510, %edx; outw %ax, (%dx); mov $0x511, %dx; cld; .dc.b 
> > 0xf3,0x6c
> >                                                                             
> >                                                           ^
> > gmake[1]: *** [multiboot.o] Error 1

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