Re: arm-elf snafu? can't mix default-soft-float, explicit -msoft-float

[Nick Clifton <nickc@redhat.com>]

Hi Doug,

> Simple testcase:
>
> bash$ rm foo1.c foo2.c ; touch foo1.c foo2.c
> bash$ arm-elf-gcc -c foo1.c
> bash$ arm-elf-objdump -p foo1.o
> foo1.o:     file format elf32-littlearm
> private flags = 0: [APCS-32] [FPA float format]
> bash$ arm-elf-gcc -c foo2.c -msoft-float
> foo1.o:     file format elf32-littlearm
> private flags = 200: [APCS-32] [FPA float format] [software FP]
> bash$ arm-elf-gcc -nostdlib foo1.o foo2.o
> [links successfully]
> bash$ arm-elf-gcc -nostdlib foo2.o foo1.o
> /samantha/gnu-pure/rel/lib/gcc-lib/arm-elf/3.4/../../../../arm-elf/bin/ld: ERROR: foo1.o uses hardware FP, whereas a.out uses software FP

> This line in gcc/config/arm/elf.h
> 
> #ifndef SUBTARGET_ASM_FLOAT_SPEC
> #define SUBTARGET_ASM_FLOAT_SPEC "\
> %{mapcs-float:-mfloat} %{msoft-float:-mfpu=softfpa}"
> #endif


I think that this is the problem.  If you apply the patch below for
example, then arm-elf targets will always pass -mfpu=softfpa to GAS,
unless -mhard-float is specfied, whereas the arm-linux toolchain will
always pass an explicit -mfpu=fpa unless -msoft-float is specified.

What do you think ?

Cheers
        Nick

gcc/ChangeLog                
2003-07-23  Nick Clifton  <nickc@redhat.com>

	* config/arm/elf.h (SUBTARGET_ASM_FLOAT_SPEC): Pass
	-mfpu=softfpa to GAS by default.
	* config/arm/linux-elf.h (SUBTARGET_ASM_FLOAT_SPEC): Define.
        Pass -mfpu=fpa to GAS by default.

Index: gcc/config/arm/elf.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/arm/elf.h,v
retrieving revision 1.44
diff -c -3 -p -r1.44 elf.h
*** gcc/config/arm/elf.h	19 Jun 2003 21:47:06 -0000	1.44
--- gcc/config/arm/elf.h	23 Jul 2003 18:32:24 -0000
***************
*** 46,52 ****
  
  #ifndef SUBTARGET_ASM_FLOAT_SPEC
  #define SUBTARGET_ASM_FLOAT_SPEC "\
! %{mapcs-float:-mfloat} %{msoft-float:-mfpu=softfpa}"
  #endif
  
  #ifndef ASM_SPEC
--- 46,52 ----
  
  #ifndef SUBTARGET_ASM_FLOAT_SPEC
  #define SUBTARGET_ASM_FLOAT_SPEC "\
! %{mapcs-float:-mfloat} %{!mhard-float:-mfpu=softfpa} %{mhard-float:-mfpu=fpa}"
  #endif
  
  #ifndef ASM_SPEC
  
Index: gcc/config/arm/linux-elf.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/arm/linux-elf.h,v
retrieving revision 1.40
diff -c -3 -p -r1.40 linux-elf.h
*** gcc/config/arm/linux-elf.h	14 Jun 2003 17:11:57 -0000	1.40
--- gcc/config/arm/linux-elf.h	23 Jul 2003 18:32:24 -0000
***************
*** 40,45 ****
--- 40,49 ----
  #define MULTILIB_DEFAULTS \
  	{ "marm", "mlittle-endian", "mhard-float", "mapcs-32", "mno-thumb-interwork" }
  
+ #undef  SUBTARGET_ASM_FLOAT_SPEC
+ #define SUBTARGET_ASM_FLOAT_SPEC "\
+   %{mapcs-float:-mfloat} %{!msoft-float:-mfpu=fpa} %{msoft-float:-mfpu=softfpa}"
+ 
  #define CPP_APCS_PC_DEFAULT_SPEC "-D__APCS_32__"
  
  /* The GNU C++ standard library requires that these macros be defined.  */