Re: arm-unknown-linux-gnueabi ABI selection

["Yann E. MORIN" <yann dot morin dot 1998 at anciens dot enib dot fr>]

On Sunday 31 August 2008 17:49:30 Michael Abbott wrote:
> 
> On Sun, 31 Aug 2008, Michael Abbott wrote:
> > > 2. I can't build a good toolchain (sizeof(enum)==1 is a disaster).
> > I may have spotted a discrepancy, with CT_ARCH_ABI_CFLAGS where it looks 
> > as if CT_ARCH_ABI_CFLAG was meant.  
> ...
> > I'll make an update in an hour when the build is complete.
> And ... it still doesn't work.

OK, working on Marc's idea, I managed to have a 'working' EABI toolchain:

# cat test.c
enum test { TEST };
int size() { return sizeof(enum test); }
# ./arm-unknown-linux-gnueabi/bin/arm-unknown-linux-gnueabi-gcc -O2 -S test.c
# cat test.s
        .arch armv5te
        .fpu softvfp
        .eabi_attribute 20, 1
        .eabi_attribute 21, 1
        .eabi_attribute 23, 3
        .eabi_attribute 24, 1
        .eabi_attribute 25, 1
        .eabi_attribute 26, 2
        .eabi_attribute 30, 2
        .eabi_attribute 18, 4
        .file   "test.c"
        .text
        .align  2
        .global size
        .type   size, %function
size:
        @ args = 0, pretend = 0, frame = 0
        @ frame_needed = 0, uses_anonymous_args = 0
        @ link register save eliminated.
        mov     r0, #4
        bx      lr
        .size   size, .-size
        .ident  "GCC: (crosstool-NG-1.2.0+svn_trunk@970M) 4.3.1"
        .section        .note.GNU-stack,"",%progbits
# ./arm-unknown-linux-gnueabi/bin/arm-unknown-linux-gnueabi-gcc -O2 \
  -c test.c -o test.o
# ./arm-unknown-linux-gnueabi/bin/arm-unknown-linux-gnueabi-readelf -h test.o
ELF Header:
  Magic:   7f 45 4c 46 01 01 01 00 00 00 00 00 00 00 00 00
  Class:                             ELF32
  Data:                              2's complement, little endian
  Version:                           1 (current)
  OS/ABI:                            UNIX - System V
  ABI Version:                       0
  Type:                              REL (Relocatable file)
  Machine:                           ARM
  Version:                           0x1
  Entry point address:               0x0
  Start of program headers:          0 (bytes into file)
  Start of section headers:          236 (bytes into file)
  Flags:                             0x4000000, Version4 EABI
  Size of this header:               52 (bytes)
  Size of program headers:           0 (bytes)
  Number of program headers:         0
  Size of section headers:           40 (bytes)
  Number of section headers:         10
  Section header string table index: 7

Seems in the case of EABI, we must entirely leave out the --with-abi and -mabi
flags, as Marc said. So, is the above an EABI-compliant toolchain?

Michael, care to test further the attached patch? If that's OK, then I'll
remove the ABI config option in case EABI is selected.

BTW, Michael, I saw you were using gcc-4.2.4. I'm using 4.3.1, and got the
same results as yours without the patch. I did not test the patch with 4.2.4.

Regards,
Yann E. MORIN.

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Index: ct-ng.trunk/arch/arm/functions
===================================================================
--- ct-ng.trunk/arch/arm/functions	(revision 970)
+++ ct-ng.trunk/arch/arm/functions	(working copy)
@@ -12,20 +12,9 @@
         uClibc,y)   CT_TARGET_SYS=uclibcgnueabi;;
     esac
 
-    case "${CT_ARCH_ABI},${CT_ARCH_ARM_EABI}" in
-        *,) ;;
-        aapcs,y)
-            CT_DoLog DEBUG "'--with-abi=aapcs' is in fact '-mabi=aapcs-linux' when used in CFLAGS."
-            CT_ARCH_ABI_CFLAGS="-mabi=aapcs-linux"
-            ;;
-        ,y)
-            CT_DoLog WARN "Forcing ABI to 'aapcs-linux' for use with EABI."
-            CT_ARCH_WITH_ABI="--with-abi=aapcs"
-            CT_ARCH_ABI_CFLAGS="-mabi=aapcs-linux"
-            ;;
-        *,y)
-            CT_DoLog ERROR "ABI='${CT_ARCH_ABI}' not supported for EABI."
-            CT_Abort "If you know you are right, please edit 'arch/arm/functions' in crosstool-NG sources."
-            ;;
-    esac
+    if [ "${CT_ARCH_ARM_EABI}" = "y" ]; then
+        CT_DoLog DEBUG "Removing any ABI flag for EABI"
+        CT_ARCH_WITH_ABI=
+        CT_ARCH_ABI_CFLAG=
+    fi
 }

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