Bug 6726

Created attachment 2817 [details]
contains the Makefile, Assembly file and C file to reproduce the problem

Makefile, ARM assembly, C code to reproduce the problem

here are the output and error messages:

----------------------------------------------------------------------------

veneer2> make
arm-elf-as  -mno-fpu -march=armv4t -mcpu=arm7tdmi -mthumb-interwork -o 
FirstAsm.
o FirstAsm.s
arm-elf-as  -mno-fpu -march=armv4t -mcpu=arm7tdmi -mthumb-interwork -o 
SecondAsm
.o SecondAsm.s
arm-elf-gcc -O0  -march=armv4t -mcpu=arm7tdmi -mthumb-interwork -mthumb 
-c -o Th
irdC.o ThirdC.c
arm-elf-objdump -S FirstAsm.o > FirstAsm.lst
arm-elf-objdump -S SecondAsm.o > SecondAsm.lst
arm-elf-objdump -S ThirdC.o > ThirdC.lst
arm-elf-ld --gc-sections -Ttext 0x40001000 --section-start 
FirstSection=0x400000
00 --defsym _start=0x400C0000 -o FinalProgram.elf FirstAsm.o SecondAsm.o 
ThirdC.
o
arm-elf-ld: internal error ../../binutils-2.17/ld/ldlang.c 4275
make: *** [all] Error 1

----------------------------------------------------------------------------

as you can see, we get the error from ldlang.c line 4275. as soon as you
remove -gc-sections, this error goes away.

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Created attachment 2818 [details]
contains the Makefile, Assembly file and C file to reproduce the problem

contains the Makefile, Assembly file and C file to reproduce the problem

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Created attachment 2819 [details]
Makefile, 2 assembly files, C file to prevent the error

Makefile, 2 assembly files, C file to prevent the error

i found a way to prevent the error from occuring.
all you have to do is to insert a global symbol
in the first section that is resolved by another
file that is also linked in at the same time.
voila! the problem disappears!

i found out how to eliminate the problem:

- when you enable --gc-sections and Thumb interworking,
  all you need to do is to define the entry point.
  either define _start or the symbol defined using
  --entry=<entry_point>

in t2, we have defined _start, that solved the problem.

Hi Aaron,

  I believe that this is an old problem, and that if you try the latest binutils
sources (from the mainline of the CVS repository) you will find that the bug
goes away.

Cheers
  Nick

Additional:

  I should also point out that you should not be invoking the linker directly. 
Please use gcc to run the linker as this will ensure that the correct command
line options are used.

Cheers
  Nick

good day Nick:

> if you try the latest binutils sources (from the mainline of the CVS
> repository) you will find that the bug goes away.

how do i build binutils from source for ARM?
i followed instructions on http://www.gnuarm.com/support.html

# cd [binutils-build]
# [binutils-source]/configure --target=arm-elf --prefix=[toolchain-prefix]
#   --enable-interwork --enable-multilib
# make all install

i found this to be incorrect. so, i changed it to:
--program-prefix=arm-elf --prefix=${HOME}/local --target=arm-elf

however, i get a message that i am building for arm-unknown-elf.
what should i do?

btw, i am no longer on the GCC list, so you know.

Aaron

hello Nick again:

> I should also point out that you should not be invoking the linker directly. 
> Please use gcc to run the linker as this will ensure that the correct command
> line options are used.

however, if i use GCC to link, i will not be able to position the
objects and libraries in the order i want. currently, i want to:
- skip linking with crt0.o
- optionally link in crtbegin.o and the others when they are needed
- link one of my objects first
- link the other objects
- link the libraries
- link another of my objects last

if i use GCC for linking, i cannot do this.

also, i have to change all the linker options to
-Wl, style whereas with LD i can place simple space
separated options.

Aaron

i just checked with the latest GNUARM distribution from GNUARM.org.
as you stated, the problem has been solved in the latest binutils.

this is the latest GNUARM package that i used for confirming the fix.
binutils-2.18, gcc-4.2.2-c-c++, newlib-1.15.0 (reentrant), insight-6.7.1,
setup.exe [102MB]

i was able to download and build binutils-2.18.50 that was released today.
after building it, i verified that the bug described in this report has
been fixed. also, i confirmed that problem in bug6727 has also been fixed.