Hello!
During development and debugging of U-Boot bootloader I got strange
error from ARM GNU assembler, which looks like a bug in binutils or gcc.
Below is simplified code which can trigger it:
$ cat test.S
kernoffs:
.word KERNEL_OFFSET - (. - CONFIG_SYS_TEXT_BASE)
$ arm-linux-gnueabi-gcc -DKERNEL_OFFSET=0x40000
-DCONFIG_SYS_TEXT_BASE=0x80008000 -pipe -c test.S
{standard input}: Assembler messages:
{standard input}: Error: attempt to get value of unresolved symbol `L0'
I do not use any L0 symbol in the code, so error message seems to be
incorrect. And also I do not think that there is issue in that simple
assembler code.
On the other hand, if I declare negated value then compilation passes
without any error/warning. Code is:
kernoffs:
.word . - CONFIG_SYS_TEXT_BASE - KERNEL_OFFSET
It is quite strange that negated value can be compiled by gcc/as without
issue here.
I was told that I should report this issue, so I'm sending email to
binutils and gcc mailing list.
Do you have any idea where is the issue? It is a bug in gcc / as or is
there some syntax / semantic error in that simple example?
Just for the record I'm using standard ARM cross compiler available on
Debian 10 Buster system. Here are version information:
$ arm-linux-gnueabi-gcc -v
Using built-in specs.
COLLECT_GCC=arm-linux-gnueabi-gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc-cross/arm-linux-gnueabi/8/lto-wrapper
Target: arm-linux-gnueabi
Configured with: ../src/configure -v --with-pkgversion='Debian 8.3.0-2'
--with-bugurl=file:///usr/share/doc/gcc-8/README.Bugs
--enable-languages=c,ada,c++,go,d,fortran,objc,obj-c++ --prefix=/usr
--with-gcc-major-version-only --program-suffix=-8 --enable-shared
--enable-linker-build-id --libexecdir=/usr/lib --without-included-gettext
--enable-threads=posix --libdir=/usr/lib --enable-nls --with-sysroot=/
--enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes
--with-default-libstdcxx-abi=new --enable-gnu-unique-object --disable-libitm
--disable-libquadmath --disable-libquadmath-support --enable-plugin
--enable-default-pie --with-system-zlib --with-target-system-zlib
--enable-multiarch --disable-sjlj-exceptions --with-arch=armv5te
--with-float=soft --disable-werror --enable-checking=release
--build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=arm-linux-gnueabi
--program-prefix=arm-linux-gnueabi- --includedir=/usr/arm-linux-gnueabi/include
Thread model: posix
gcc version 8.3.0 (Debian 8.3.0-2)
$ arm-linux-gnueabi-as --version
GNU assembler (GNU Binutils for Debian) 2.31.1
Copyright (C) 2018 Free Software Foundation, Inc.
This program is free software; you may redistribute it under the terms of
the GNU General Public License version 3 or later.
This program has absolutely no warranty.
This assembler was configured for a target of `arm-linux-gnueabi'.
