return flag;
}
+/*
+FUNCTION
+ bfd_install_relocation
+
+SYNOPSIS
+ bfd_reloc_status_type
+ bfd_install_relocation
+ (bfd *abfd,
+ arelent *reloc_entry,
+ PTR data, bfd_vma data_start,
+ asection *input_section,
+ char **error_message);
+
+DESCRIPTION
+ This looks remarkably like <<bfd_perform_relocation>>, except it
+ does not expect that the section contents have been filled in.
+ I.e., it's suitable for use when creating, rather than applying
+ a relocation.
+
+ For now, this function should be considered reserved for the
+ assembler.
+
+*/
+
+
+bfd_reloc_status_type
+bfd_install_relocation (abfd, reloc_entry, data_start, data_start_offset,
+ input_section, error_message)
+ bfd *abfd;
+ arelent *reloc_entry;
+ PTR data_start;
+ bfd_vma data_start_offset;
+ asection *input_section;
+ char **error_message;
+{
+ bfd_vma relocation;
+ bfd_reloc_status_type flag = bfd_reloc_ok;
+ bfd_size_type addr = reloc_entry->address;
+ bfd_vma output_base = 0;
+ const reloc_howto_type *howto = reloc_entry->howto;
+ asection *reloc_target_output_section;
+ asymbol *symbol;
+ PTR data;
+
+ symbol = *(reloc_entry->sym_ptr_ptr);
+ if (bfd_is_abs_section (symbol->section))
+ {
+ reloc_entry->address += input_section->output_offset;
+ return bfd_reloc_ok;
+ }
+
+ /* If there is a function supplied to handle this relocation type,
+ call it. It'll return `bfd_reloc_continue' if further processing
+ can be done. */
+ if (howto->special_function)
+ {
+ bfd_reloc_status_type cont;
+ /* XXX - The special_function calls haven't been fixed up to deal
+ with creating new relocations and section contents. */
+ cont = howto->special_function (abfd, reloc_entry, symbol,
+ /* XXX - Non-portable! */
+ ((bfd_byte *) data_start
+ - data_start_offset),
+ input_section, abfd, error_message);
+ if (cont != bfd_reloc_continue)
+ return cont;
+ }
+
+ /* Is the address of the relocation really within the section? */
+ if (reloc_entry->address > input_section->_cooked_size)
+ return bfd_reloc_outofrange;
+
+ /* Work out which section the relocation is targetted at and the
+ initial relocation command value. */
+
+ /* Get symbol value. (Common symbols are special.) */
+ if (bfd_is_com_section (symbol->section))
+ relocation = 0;
+ else
+ relocation = symbol->value;
+
+
+ reloc_target_output_section = symbol->section->output_section;
+
+ /* Convert input-section-relative symbol value to absolute. */
+ if (howto->partial_inplace == false)
+ output_base = 0;
+ else
+ output_base = reloc_target_output_section->vma;
+
+ relocation += output_base + symbol->section->output_offset;
+
+ /* Add in supplied addend. */
+ relocation += reloc_entry->addend;
+
+ /* Here the variable relocation holds the final address of the
+ symbol we are relocating against, plus any addend. */
+
+ if (howto->pc_relative == true)
+ {
+ /* This is a PC relative relocation. We want to set RELOCATION
+ to the distance between the address of the symbol and the
+ location. RELOCATION is already the address of the symbol.
+
+ We start by subtracting the address of the section containing
+ the location.
+
+ If pcrel_offset is set, we must further subtract the position
+ of the location within the section. Some targets arrange for
+ the addend to be the negative of the position of the location
+ within the section; for example, i386-aout does this. For
+ i386-aout, pcrel_offset is false. Some other targets do not
+ include the position of the location; for example, m88kbcs,
+ or ELF. For those targets, pcrel_offset is true.
+
+ If we are producing relocateable output, then we must ensure
+ that this reloc will be correctly computed when the final
+ relocation is done. If pcrel_offset is false we want to wind
+ up with the negative of the location within the section,
+ which means we must adjust the existing addend by the change
+ in the location within the section. If pcrel_offset is true
+ we do not want to adjust the existing addend at all.
+
+ FIXME: This seems logical to me, but for the case of
+ producing relocateable output it is not what the code
+ actually does. I don't want to change it, because it seems
+ far too likely that something will break. */
+
+ relocation -=
+ input_section->output_section->vma + input_section->output_offset;
+
+ if (howto->pcrel_offset == true && howto->partial_inplace == true)
+ relocation -= reloc_entry->address;
+ }
+
+ if (howto->partial_inplace == false)
+ {
+ /* This is a partial relocation, and we want to apply the relocation
+ to the reloc entry rather than the raw data. Modify the reloc
+ inplace to reflect what we now know. */
+ reloc_entry->addend = relocation;
+ reloc_entry->address += input_section->output_offset;
+ return flag;
+ }
+ else
+ {
+ /* This is a partial relocation, but inplace, so modify the
+ reloc record a bit.
+
+ If we've relocated with a symbol with a section, change
+ into a ref to the section belonging to the symbol. */
+
+ reloc_entry->address += input_section->output_offset;
+
+ /* WTF?? */
+ if (abfd->xvec->flavour == bfd_target_coff_flavour
+ && strcmp (abfd->xvec->name, "aixcoff-rs6000") != 0
+ && strcmp (abfd->xvec->name, "coff-Intel-little") != 0
+ && strcmp (abfd->xvec->name, "coff-Intel-big") != 0)
+ {
+#if 1
+/* For m68k-coff, the addend was being subtracted twice during
+ relocation with -r. Removing the line below this comment
+ fixes that problem; see PR 2953.
+
+However, Ian wrote the following, regarding removing the line below,
+which explains why it is still enabled: --djm
+
+If you put a patch like that into BFD you need to check all the COFF
+linkers. I am fairly certain that patch will break coff-i386 (e.g.,
+SCO); see coff_i386_reloc in coff-i386.c where I worked around the
+problem in a different way. There may very well be a reason that the
+code works as it does.
+
+Hmmm. The first obvious point is that bfd_install_relocation should
+not have any tests that depend upon the flavour. It's seem like
+entirely the wrong place for such a thing. The second obvious point
+is that the current code ignores the reloc addend when producing
+relocateable output for COFF. That's peculiar. In fact, I really
+have no idea what the point of the line you want to remove is.
+
+A typical COFF reloc subtracts the old value of the symbol and adds in
+the new value to the location in the object file (if it's a pc
+relative reloc it adds the difference between the symbol value and the
+location). When relocating we need to preserve that property.
+
+BFD handles this by setting the addend to the negative of the old
+value of the symbol. Unfortunately it handles common symbols in a
+non-standard way (it doesn't subtract the old value) but that's a
+different story (we can't change it without losing backward
+compatibility with old object files) (coff-i386 does subtract the old
+value, to be compatible with existing coff-i386 targets, like SCO).
+
+So everything works fine when not producing relocateable output. When
+we are producing relocateable output, logically we should do exactly
+what we do when not producing relocateable output. Therefore, your
+patch is correct. In fact, it should probably always just set
+reloc_entry->addend to 0 for all cases, since it is, in fact, going to
+add the value into the object file. This won't hurt the COFF code,
+which doesn't use the addend; I'm not sure what it will do to other
+formats (the thing to check for would be whether any formats both use
+the addend and set partial_inplace).
+
+When I wanted to make coff-i386 produce relocateable output, I ran
+into the problem that you are running into: I wanted to remove that
+line. Rather than risk it, I made the coff-i386 relocs use a special
+function; it's coff_i386_reloc in coff-i386.c. The function
+specifically adds the addend field into the object file, knowing that
+bfd_install_relocation is not going to. If you remove that line, then
+coff-i386.c will wind up adding the addend field in twice. It's
+trivial to fix; it just needs to be done.
+
+The problem with removing the line is just that it may break some
+working code. With BFD it's hard to be sure of anything. The right
+way to deal with this is simply to build and test at least all the
+supported COFF targets. It should be straightforward if time and disk
+space consuming. For each target:
+ 1) build the linker
+ 2) generate some executable, and link it using -r (I would
+ probably use paranoia.o and link against newlib/libc.a, which
+ for all the supported targets would be available in
+ /usr/cygnus/progressive/H-host/target/lib/libc.a).
+ 3) make the change to reloc.c
+ 4) rebuild the linker
+ 5) repeat step 2
+ 6) if the resulting object files are the same, you have at least
+ made it no worse
+ 7) if they are different you have to figure out which version is
+ right
+*/
+ relocation -= reloc_entry->addend;
+#endif
+ reloc_entry->addend = 0;
+ }
+ else
+ {
+ reloc_entry->addend = relocation;
+ }
+ }
+
+ /* FIXME: This overflow checking is incomplete, because the value
+ might have overflowed before we get here. For a correct check we
+ need to compute the value in a size larger than bitsize, but we
+ can't reasonably do that for a reloc the same size as a host
+ machine word.
+
+ FIXME: We should also do overflow checking on the result after
+ adding in the value contained in the object file. */
+ if (howto->complain_on_overflow != complain_overflow_dont)
+ {
+ bfd_vma check;
+
+ /* Get the value that will be used for the relocation, but
+ starting at bit position zero. */
+ if (howto->rightshift > howto->bitpos)
+ check = relocation >> (howto->rightshift - howto->bitpos);
+ else
+ check = relocation << (howto->bitpos - howto->rightshift);
+ switch (howto->complain_on_overflow)
+ {
+ case complain_overflow_signed:
+ {
+ /* Assumes two's complement. */
+ bfd_signed_vma reloc_signed_max = (1 << (howto->bitsize - 1)) - 1;
+ bfd_signed_vma reloc_signed_min = ~reloc_signed_max;
+
+ /* The above right shift is incorrect for a signed value.
+ Fix it up by forcing on the upper bits. */
+ if (howto->rightshift > howto->bitpos
+ && (bfd_signed_vma) relocation < 0)
+ check |= ((bfd_vma) - 1
+ & ~((bfd_vma) - 1
+ >> (howto->rightshift - howto->bitpos)));
+ if ((bfd_signed_vma) check > reloc_signed_max
+ || (bfd_signed_vma) check < reloc_signed_min)
+ flag = bfd_reloc_overflow;
+ }
+ break;
+ case complain_overflow_unsigned:
+ {
+ /* Assumes two's complement. This expression avoids
+ overflow if howto->bitsize is the number of bits in
+ bfd_vma. */
+ bfd_vma reloc_unsigned_max =
+ (((1 << (howto->bitsize - 1)) - 1) << 1) | 1;
+
+ if ((bfd_vma) check > reloc_unsigned_max)
+ flag = bfd_reloc_overflow;
+ }
+ break;
+ case complain_overflow_bitfield:
+ {
+ /* Assumes two's complement. This expression avoids
+ overflow if howto->bitsize is the number of bits in
+ bfd_vma. */
+ bfd_vma reloc_bits = (((1 << (howto->bitsize - 1)) - 1) << 1) | 1;
+
+ if (((bfd_vma) check & ~reloc_bits) != 0
+ && ((bfd_vma) check & ~reloc_bits) != (-1 & ~reloc_bits))
+ {
+ /* The above right shift is incorrect for a signed
+ value. See if turning on the upper bits fixes the
+ overflow. */
+ if (howto->rightshift > howto->bitpos
+ && (bfd_signed_vma) relocation < 0)
+ {
+ check |= ((bfd_vma) - 1
+ & ~((bfd_vma) - 1
+ >> (howto->rightshift - howto->bitpos)));
+ if (((bfd_vma) check & ~reloc_bits) != (-1 & ~reloc_bits))
+ flag = bfd_reloc_overflow;
+ }
+ else
+ flag = bfd_reloc_overflow;
+ }
+ }
+ break;
+ default:
+ abort ();
+ }
+ }
+
+ /*
+ Either we are relocating all the way, or we don't want to apply
+ the relocation to the reloc entry (probably because there isn't
+ any room in the output format to describe addends to relocs)
+ */
+
+ /* The cast to bfd_vma avoids a bug in the Alpha OSF/1 C compiler
+ (OSF version 1.3, compiler version 3.11). It miscompiles the
+ following program:
+
+ struct str
+ {
+ unsigned int i0;
+ } s = { 0 };
+
+ int
+ main ()
+ {
+ unsigned long x;
+
+ x = 0x100000000;
+ x <<= (unsigned long) s.i0;
+ if (x == 0)
+ printf ("failed\n");
+ else
+ printf ("succeeded (%lx)\n", x);
+ }
+ */
+
+ relocation >>= (bfd_vma) howto->rightshift;
+
+ /* Shift everything up to where it's going to be used */
+
+ relocation <<= (bfd_vma) howto->bitpos;
+
+ /* Wait for the day when all have the mask in them */
+
+ /* What we do:
+ i instruction to be left alone
+ o offset within instruction
+ r relocation offset to apply
+ S src mask
+ D dst mask
+ N ~dst mask
+ A part 1
+ B part 2
+ R result
+
+ Do this:
+ i i i i i o o o o o from bfd_get<size>
+ and S S S S S to get the size offset we want
+ + r r r r r r r r r r to get the final value to place
+ and D D D D D to chop to right size
+ -----------------------
+ A A A A A
+ And this:
+ ... i i i i i o o o o o from bfd_get<size>
+ and N N N N N get instruction
+ -----------------------
+ ... B B B B B
+
+ And then:
+ B B B B B
+ or A A A A A
+ -----------------------
+ R R R R R R R R R R put into bfd_put<size>
+ */
+
+#define DOIT(x) \
+ x = ( (x & ~howto->dst_mask) | (((x & howto->src_mask) + relocation) & howto->dst_mask))
+
+ data = (bfd_byte *) data_start + (addr - data_start_offset);
+
+ switch (howto->size)
+ {
+ case 0:
+ {
+ char x = bfd_get_8 (abfd, (char *) data);
+ DOIT (x);
+ bfd_put_8 (abfd, x, (unsigned char *) data);
+ }
+ break;
+
+ case 1:
+ if (relocation)
+ {
+ short x = bfd_get_16 (abfd, (bfd_byte *) data);
+ DOIT (x);
+ bfd_put_16 (abfd, x, (unsigned char *) data);
+ }
+ break;
+ case 2:
+ if (relocation)
+ {
+ long x = bfd_get_32 (abfd, (bfd_byte *) data);
+ DOIT (x);
+ bfd_put_32 (abfd, x, (bfd_byte *) data);
+ }
+ break;
+ case -2:
+ {
+ long x = bfd_get_32 (abfd, (bfd_byte *) data);
+ relocation = -relocation;
+ DOIT (x);
+ bfd_put_32 (abfd, x, (bfd_byte *) data);
+ }
+ break;
+
+ case 3:
+ /* Do nothing */
+ break;
+
+ case 4:
+ if (relocation)
+ {
+ bfd_vma x = bfd_get_64 (abfd, (bfd_byte *) data);
+ DOIT (x);
+ bfd_put_64 (abfd, x, (bfd_byte *) data);
+ }
+ break;
+ default:
+ return bfd_reloc_other;
+ }
+
+ return flag;
+}
+
/* This relocation routine is used by some of the backend linkers.
They do not construct asymbol or arelent structures, so there is no
reason for them to use bfd_perform_relocation. Also,
probably a 32 bit wide absolute relocation, but the target can choose.
It generally does map to one of the other relocation types.
+ENUM
+ BFD_RELOC_ARM_PCREL_BRANCH
+ENUMDOC
+ ARM 26 bit pc-relative branch. The lowest two bits must be zero and are
+ not stored in the instruction.
+ENUM
+ BFD_RELOC_ARM_IMMEDIATE
+ENUMX
+ BFD_RELOC_ARM_OFFSET_IMM
+ENUMX
+ BFD_RELOC_ARM_SHIFT_IMM
+ENUMX
+ BFD_RELOC_ARM_SWI
+ENUMX
+ BFD_RELOC_ARM_MULTI
+ENUMX
+ BFD_RELOC_ARM_CP_OFF_IMM
+ENUMDOC
+ These relocs are only used within the ARM assembler. They are not
+ (at present) written to any object files.
+
ENDSENUM
BFD_RELOC_UNUSED
projects / binutils-gdb.git / commitdiff