Ian Lance Taylor <ian@airs.com> writes:
> DJ Delorie <[EMAIL PROTECTED]> writes:
>> For mips-elf builds, crtbegin.o is built with -G 0 ("in case $gp isn't
>> used"). This makes __dso_handle be put in .data. However, the
>> "prototype" created by cp/decl.c is "void *__dso_data" which causes
>> GPrel addressing if your application is built without -G 0 (i.e. the
>> default), which causes link problems. This is causing numerous
>> testsuite failures like this example:
>>
>> /dev/shm/ccvHNaHr.o: In function
>> `__static_initialization_and_destruction_0(int, int)':
>> omit-frame-pointer.C:(.text+0x58): relocation truncated to fit:
>> R_MIPS_GPREL16 against `__dso_handle'
>>
>> Ideas?
>
> Hack mips_in_small_data_p to check for this magic symbol and return
> false for it?
I think that's the wrong way around. This looks to me like just another
case of the general rule that compiling x.c with -G0 and y.c with -GA (A>0)
is not safe if y.c refers to a normal B-byte (B<=A) variable in x.c.
Since the point of compiling libgcc and crt* with -G0 is precisely
to allow them to be linked with such -GA code, I think each variable
exported by them should be put into a small data section using
__attribute__((section...)). This is what newlib does with its
_impure_ptr, for example.
[IMO, MIPS linker scripts should always include *(.sdata), even if every
object is compiled with -G0. But even if a linker script doesn't include
.sdata, the linker orphan placement code should do something sensible.]
DJ: I was planning to look at this myself, but it sounds like your need
is more urgent than mine. Are you going to be doing this very soon?
Richard
