ARM bootstrap failure PR 46040 (Re: [PATCH] move DECLARE_LIBRARY_RENAMES to libgcc headers)

["Ulrich Weigand" <uweigand at de dot ibm dot com>]

Nathan Froyd wrote:

> (The intent is to move as much target library-specific stuff into libgcc
> first, then eventually move all the configuration hunks into libgcc's
> configury.  Doing so should be straightforward, as the
> ../../libgcc/config/ paths stick out like sore thumbs.  If other people
> have ideas on how the transition should go, I'm happy to hear them.)

It seems this patch broke bootstrap on ARM, causing PR 46040:

uweigand@localhost:~/gcc-head-build/armv7l-unknown-linux-gnueabi/libgcc$ /home/uweigand/gcc-head-build/./gcc/xgcc -B/home/uweigand/gcc-head-build/./gcc/ -B/home/uweigand/gcc-head-install/armv7l-unknown-linux-gnueabi/bin/ -B/home/uweigand/gcc-head-install/armv7l-unknown-linux-gnueabi/lib/ -isystem /home/uweigand/gcc-head-install/armv7l-unknown-linux-gnueabi/include -isystem /home/uweigand/gcc-head-install/armv7l-unknown-linux-gnueabi/sys-include    -g -O2 -O2 -g -O2 -DIN_GCC   -W -Wall -Wwrite-strings -Wcast-qual -Wstrict-prototypes -Wmissing-prototypes -Wold-style-definition  -isystem ./include  -I. -I. -I../../gcc-head/gcc -I../../gcc-head/gcc/. -I../../gcc-head/gcc/../include -I../../gcc-head/gcc/../libcpp/include  -I../../gcc-head/gcc/../libdecnumber -I../../gcc-head/gcc/../libdecnumber/dpd -I../libdecnumber    -g0 -finhibit-size-directive -fno-inline -fno-exceptions -fno-zero-initialized-in-bss -fno-toplevel-reorder -fno-tree-vectorize -fno-stack-protector  -I. -I. -I../!
 .././gcc -I../../../gcc-head/libgcc -I../../../gcc-head/libgcc/. -I../../../gcc-head/libgcc/../gcc -I../../../gcc-head/libgcc/../include  -o crtbegin.o -MT crtbegin.o -MD -MP -MF crtbegin.dep            -c ../../../gcc-head/libgcc/../gcc/crtstuff.c -DCRT_BEGIN
../../../gcc-head/libgcc/../gcc/crtstuff.c: In function "__do_global_dtors_aux":
../../../gcc-head/libgcc/../gcc/crtstuff.c:308:26: error: "__DTOR_LIST__" undeclared (first use in this function)
../../../gcc-head/libgcc/../gcc/crtstuff.c:308:26: note: each undeclared identifier is reported only once for each function it appears in

The problem is this change:

>  	case ${target} in
>  	arm*-*-linux-*eabi)
>  	    tm_file="$tm_file arm/bpabi.h arm/linux-eabi.h"
> +	    tm_file="$tm_file ../../libgcc/config/arm/bpabi.h"
>  	    tmake_file="$tmake_file arm/t-arm-elf arm/t-bpabi arm/t-linux-eabi t-slibgcc-libgcc"
>  	    # Define multilib configuration for arm-linux-androideabi.
>  	    case ${target} in

While compiling GCC itself, we're pulling in both files
    gcc/config/arm/bpabi.h
    libgcc/config/arm/bpapi.h
so everything works as before.

But if we're compiling libgcc, the relative path "arm/bpabi.h"
already refers to the file libgcc/config/arm/bpapi.h, so this
gets included twice, and gcc/config/arm/bpabi.h does not get
included at all any more.

However, there are certain defines in the latter file that also
influence libgcc, in particular those lines:

/* The BPABI specifies the use of .{init,fini}_array.  Therefore, we
   do not want GCC to put anything into the .{init,fini} sections.  */
#undef INIT_SECTION_ASM_OP
#undef FINI_SECTION_ASM_OP
#define INIT_ARRAY_SECTION_ASM_OP ARM_EABI_CTORS_SECTION_OP
#define FINI_ARRAY_SECTION_ASM_OP ARM_EABI_DTORS_SECTION_OP

Since these are now no longer present, we're running into inconsistencies
while building the crt* startup files.

Bye,
Ulrich

-- 
  Dr. Ulrich Weigand
  GNU Toolchain for Linux on System z and Cell BE
  Ulrich.Weigand@de.ibm.com