Re: ld bug - thumb code

[andy parker]

Hi Nick,

Apologies for confusion over the test case. cdbg() is a home-spun output 
stream providing some iostream-like functionality via a serial port. You 
can just delete these lines or replace with cdbg() with cout, if your 
system supports it.

The arm compiler I'm using is arm-elf-g++ version 3.2.
My compiler command line is:

arm-elf-g++ -pipe -Wall -Wmissing-declarations -Wmissing-prototypes 
-Wstrict-prototypes -Wpointer-arith -fno-omit-frame-pointer 
-mlittle-endian -fbuiltin -fno-exceptions -fno-rtti -mcpu=arm9 
-mno-sched-prolog  -fno-exceptions -fno-rtti -Os -finline-functions 
-finline-limit=250  -mthumb -Isrc -c src/a.cxx -o object/a.o

I have stripped out the the internal library calls and attached an 
example tarball which builds two simple test cases, one arm and one 
thumb. In this case, the linker does not produce a relocation eror, but 
I believe the code is wrong, and this may be related the original 
relocation error.

The disassembled thumb image appears to contain a corrupted thunk:

00000188 <_ZThn4_N1C1FEv>:
 188:    3804          sub    r0, #4
 18a:    e345          b    818 <_ramstart+0x68c>
since no valid code exists at 818.

However, the arm case correctly branches to C::F(),
00000194 <_ZThn4_N1C1FEv>:
 194:    e2400004     sub    r0, r0, #4    ; 0x4
 198:    eaffffd2     b    e8 <_ZN1C1FEv>

Any thoughts ?

Cheers,
Andy Parker

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Description: GNU Zip compressed data