Hi,
I am trying to compile a C++ program using templates for uClinux.
I get massive problems with weak symbols - it looks like the
elf2flt and/or ld is not able to use the weak symbols.
The toolchain is a self-compiled binutils 2.17, gcc 4.2.1-based one.
Compiling and linking the files in attach gets me bogus message
ERROR: text=0xbec0 overlaps data=0x0 ?
collect2: ld returned 1 exit status
The code compiles fine with -fno-weak, but this is
an unsupported flag and creates other problems.
objdump gives me (uninteresting debug/comment sections stripped):
weak1.o: file format elf32-littlearm
Sections:
Idx Name Size VMA LMA File off Algn
0 _ZN7MyClassIiEC1Ev 00000008 00000000 00000000 00000034 2**2
CONTENTS, READONLY, EXCLUDE, GROUP, LINK_ONCE_DISCARD
1 _ZN7MyClassIiED0Ev 00000008 00000000 00000000 0000003c 2**2
CONTENTS, READONLY, EXCLUDE, GROUP, LINK_ONCE_DISCARD
2 _ZN7MyClassIiED1Ev 00000008 00000000 00000000 00000044 2**2
CONTENTS, READONLY, EXCLUDE, GROUP, LINK_ONCE_DISCARD
3 _ZTV7MyClassIiE 00000008 00000000 00000000 0000004c 2**2
CONTENTS, READONLY, EXCLUDE, GROUP, LINK_ONCE_DISCARD
4 .text 00000070 00000000 00000000 00000054 2**2
CONTENTS, ALLOC, LOAD, RELOC, READONLY, CODE
5 .data 00000000 00000000 00000000 000000c4 2**0
CONTENTS, ALLOC, LOAD, DATA
6 .bss 00000000 00000000 00000000 000000c4 2**0
ALLOC
10 .text._ZN7MyClassIiEC1Ev 00000028 00000000 00000000 0000046c 2**2
CONTENTS, ALLOC, LOAD, RELOC, READONLY, CODE
11 .text._ZN7MyClassIiED0Ev 00000040 00000000 00000000 00000494 2**2
CONTENTS, ALLOC, LOAD, RELOC, READONLY, CODE
12 .text._ZN7MyClassIiED1Ev 00000040 00000000 00000000 000004d4 2**2
CONTENTS, ALLOC, LOAD, RELOC, READONLY, CODE
13 .rodata._ZTV7MyClassIiE 00000010 00000000 00000000 00000514 2**2
CONTENTS, ALLOC, LOAD, RELOC, READONLY, DATA
weak2.o: file format elf32-littlearm
Sections:
Idx Name Size VMA LMA File off Algn
0 _ZN7MyClassIiEC1Ev 00000008 00000000 00000000 00000034 2**2
CONTENTS, READONLY, EXCLUDE, GROUP, LINK_ONCE_DISCARD
1 _ZN7MyClassIiED0Ev 00000008 00000000 00000000 0000003c 2**2
CONTENTS, READONLY, EXCLUDE, GROUP, LINK_ONCE_DISCARD
2 _ZN7MyClassIiED1Ev 00000008 00000000 00000000 00000044 2**2
CONTENTS, READONLY, EXCLUDE, GROUP, LINK_ONCE_DISCARD
3 _ZTV7MyClassIiE 00000008 00000000 00000000 0000004c 2**2
CONTENTS, READONLY, EXCLUDE, GROUP, LINK_ONCE_DISCARD
4 .text 00000048 00000000 00000000 00000054 2**2
CONTENTS, ALLOC, LOAD, RELOC, READONLY, CODE
5 .data 00000000 00000000 00000000 0000009c 2**0
CONTENTS, ALLOC, LOAD, DATA
6 .bss 00000000 00000000 00000000 0000009c 2**0
ALLOC
10 .text._ZN7MyClassIiEC1Ev 00000028 00000000 00000000 000003c8 2**2
CONTENTS, ALLOC, LOAD, RELOC, READONLY, CODE
11 .text._ZN7MyClassIiED0Ev 00000040 00000000 00000000 000003f0 2**2
CONTENTS, ALLOC, LOAD, RELOC, READONLY, CODE
12 .text._ZN7MyClassIiED1Ev 00000040 00000000 00000000 00000430 2**2
CONTENTS, ALLOC, LOAD, RELOC, READONLY, CODE
13 .rodata._ZTV7MyClassIiE 00000010 00000000 00000000 00000470 2**2
CONTENTS, ALLOC, LOAD, RELOC, READONLY, DATA
The elf-linked file as produced by the elf2flt script:
weak.elf: file format elf32-littlearm
Sections:
Idx Name Size VMA LMA File off Algn
0 _ZN7MyClassIiEC1Ev 00000008 00000000 00000000 00000034 2**2
CONTENTS, READONLY, EXCLUDE, GROUP, LINK_ONCE_DISCARD
1 _ZN7MyClassIiED0Ev 00000008 00000000 00000000 0000003c 2**2
CONTENTS, READONLY, EXCLUDE, GROUP, LINK_ONCE_DISCARD
2 _ZN7MyClassIiED1Ev 00000008 00000000 00000000 00000044 2**2
CONTENTS, READONLY, EXCLUDE, GROUP, LINK_ONCE_DISCARD
3 _ZTV7MyClassIiE 00000008 00000000 00000000 0000004c 2**2
CONTENTS, READONLY, EXCLUDE, GROUP, LINK_ONCE_DISCARD
4 .text 0000bec0 00000000 00000000 00000060 2**4
CONTENTS, ALLOC, LOAD, RELOC, CODE
5 .text._ZN7MyClassIiEC1Ev 00000028 00000000 00000000 0000bf20 2**2
CONTENTS, ALLOC, LOAD, RELOC, READONLY, CODE
6 .text._ZN7MyClassIiED0Ev 00000040 00000000 00000000 0000bf48 2**2
CONTENTS, ALLOC, LOAD, RELOC, READONLY, CODE
7 .text._ZN7MyClassIiED1Ev 00000040 00000000 00000000 0000bf88 2**2
CONTENTS, ALLOC, LOAD, RELOC, READONLY, CODE
8 .rodata._ZTV7MyClassIiE 00000010 00000000 00000000 0000bfc8 2**2
CONTENTS, ALLOC, LOAD, RELOC, READONLY, DATA
9 .data 00001130 0000bec0 0000bec0 0000bfd8 2**2
CONTENTS, ALLOC, LOAD, RELOC, DATA
10 .bss 00000a50 0000cff0 0000cff0 0000d108 2**2
ALLOC
11 .stack 00000000 00000010 00000010 0000d108 2**0
CONTENTS
18 .note.GNU-stack 00000000 00000000 00000000 0000ef80 2**0
CONTENTS, READONLY, CODE
The .gdb linked file looks ok:
weak.gdb: file format elf32-littlearm
Sections:
Idx Name Size VMA LMA File off Algn
0 .text 0000bf60 00000000 00000000 00008000 2**4
CONTENTS, ALLOC, LOAD, READONLY, CODE
1 .data 00001110 0000bf60 0000bf60 00013f60 2**2
CONTENTS, ALLOC, LOAD, DATA
2 .bss 00000a50 0000d070 0000d070 00015070 2**2
ALLOC
3 .comment 000001c6 00000000 00000000 00015070 2**0
CONTENTS, READONLY
I don't understand the linker script and flags enough to be able
to debug and fix this - it looks like the elf2flt step has problems
with LINK_ONCE_DISCARD or .text.* symbols and is not able to put
them to the .text section where they belong.
Any hints?
Regards
--
Stano
#include "weak.h"
void foo()
{
MyClass<int> c;
}
main(int argc, char **argv)
{
}
#include "weak.h"
void bar()
{
MyClass<int> c;
}
template <typename T> class MyClass
{
public:
virtual ~MyClass() {}
private:
T m;
};
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