diff options
author | Nick Clifton <nickc@redhat.com> | 2007-10-19 17:31:31 +0000 |
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committer | Nick Clifton <nickc@redhat.com> | 2007-10-19 17:31:31 +0000 |
commit | bfff1642494227904c6c9a6c285cbaa6cf615bbb (patch) | |
tree | 7bf1ece58861b5e9c520e056102994251c0a7504 /gas/config/tc-mn10300.c | |
parent | 97030eea009ba78139fe20eae4585984435ac178 (diff) | |
download | fsf-binutils-gdb-bfff1642494227904c6c9a6c285cbaa6cf615bbb.zip fsf-binutils-gdb-bfff1642494227904c6c9a6c285cbaa6cf615bbb.tar.gz fsf-binutils-gdb-bfff1642494227904c6c9a6c285cbaa6cf615bbb.tar.bz2 |
Add MN10300 linker relaxation support for symbol differences
Diffstat (limited to 'gas/config/tc-mn10300.c')
-rw-r--r-- | gas/config/tc-mn10300.c | 144 |
1 files changed, 102 insertions, 42 deletions
diff --git a/gas/config/tc-mn10300.c b/gas/config/tc-mn10300.c index 671c008..5ec58bb 100644 --- a/gas/config/tc-mn10300.c +++ b/gas/config/tc-mn10300.c @@ -2141,15 +2141,21 @@ keep_going: dwarf2_emit_insn (size); } + + /* Label this frag as one that contains instructions. */ + frag_now->tc_frag_data = TRUE; } /* If while processing a fixup, a reloc really needs to be created then it is done here. */ -arelent * +arelent ** tc_gen_reloc (asection *seg ATTRIBUTE_UNUSED, fixS *fixp) { + static arelent * no_relocs = NULL; + static arelent * relocs[MAX_RELOC_EXPANSION + 1]; arelent *reloc; + reloc = xmalloc (sizeof (arelent)); reloc->howto = bfd_reloc_type_lookup (stdoutput, fixp->fx_r_type); @@ -2158,9 +2164,13 @@ tc_gen_reloc (asection *seg ATTRIBUTE_UNUSED, fixS *fixp) as_bad_where (fixp->fx_file, fixp->fx_line, _("reloc %d not supported by object file format"), (int) fixp->fx_r_type); - return NULL; + free (reloc); + return & no_relocs; } + reloc->address = fixp->fx_frag->fr_address + fixp->fx_where; + relocs[0] = reloc; + relocs[1] = NULL; if (fixp->fx_subsy && S_GET_SEGMENT (fixp->fx_subsy) == absolute_section) @@ -2173,44 +2183,33 @@ tc_gen_reloc (asection *seg ATTRIBUTE_UNUSED, fixS *fixp) { reloc->sym_ptr_ptr = NULL; - /* If we got a difference between two symbols, and the - subtracted symbol is in the current section, use a - PC-relative relocation. If both symbols are in the same - section, the difference would have already been simplified - to a constant. */ + /* If we have a difference between two (non-absolute) symbols we must + generate two relocs (one for each symbol) and allow the linker to + resolve them - relaxation may change the distances between symbols, + even local symbols defined in the same segment. */ if (S_GET_SEGMENT (fixp->fx_subsy) == seg) { - reloc->sym_ptr_ptr = xmalloc (sizeof (asymbol *)); - *reloc->sym_ptr_ptr = symbol_get_bfdsym (fixp->fx_addsy); - reloc->addend = (reloc->address - S_GET_VALUE (fixp->fx_subsy) - + fixp->fx_offset); + arelent * reloc2 = xmalloc (sizeof * reloc); - switch (fixp->fx_r_type) - { - case BFD_RELOC_8: - reloc->howto = bfd_reloc_type_lookup (stdoutput, - BFD_RELOC_8_PCREL); - return reloc; + relocs[0] = reloc2; + relocs[1] = reloc; - case BFD_RELOC_16: - reloc->howto = bfd_reloc_type_lookup (stdoutput, - BFD_RELOC_16_PCREL); - return reloc; + reloc2->address = reloc->address; + reloc2->howto = bfd_reloc_type_lookup (stdoutput, BFD_RELOC_MN10300_SYM_DIFF); + reloc2->addend = - S_GET_VALUE (fixp->fx_subsy); + reloc2->sym_ptr_ptr = xmalloc (sizeof (asymbol *)); + *reloc2->sym_ptr_ptr = symbol_get_bfdsym (fixp->fx_subsy); - case BFD_RELOC_24: - reloc->howto = bfd_reloc_type_lookup (stdoutput, - BFD_RELOC_24_PCREL); - return reloc; + reloc->addend = fixp->fx_offset; + if (S_GET_SEGMENT (fixp->fx_addsy) == absolute_section) + reloc->addend += S_GET_VALUE (fixp->fx_addsy); - case BFD_RELOC_32: - reloc->howto = bfd_reloc_type_lookup (stdoutput, - BFD_RELOC_32_PCREL); - return reloc; + reloc->sym_ptr_ptr = xmalloc (sizeof (asymbol *)); + *reloc->sym_ptr_ptr = symbol_get_bfdsym (fixp->fx_addsy); - default: - /* Try to compute the absolute value below. */ - break; - } + fixp->fx_pcrel = 0; + fixp->fx_done = 1; + return relocs; } if ((S_GET_SEGMENT (fixp->fx_addsy) != S_GET_SEGMENT (fixp->fx_subsy)) @@ -2247,14 +2246,14 @@ tc_gen_reloc (asection *seg ATTRIBUTE_UNUSED, fixS *fixp) default: reloc->sym_ptr_ptr = (asymbol **) bfd_abs_section_ptr->symbol_ptr_ptr; - return reloc; + return relocs; } } if (reloc->sym_ptr_ptr) free (reloc->sym_ptr_ptr); free (reloc); - return NULL; + return & no_relocs; } else { @@ -2262,7 +2261,7 @@ tc_gen_reloc (asection *seg ATTRIBUTE_UNUSED, fixS *fixp) *reloc->sym_ptr_ptr = symbol_get_bfdsym (fixp->fx_addsy); reloc->addend = fixp->fx_offset; } - return reloc; + return relocs; } int @@ -2377,11 +2376,14 @@ md_apply_fix (fixS * fixP, valueT * valP, segT seg) bfd_boolean mn10300_fix_adjustable (struct fix *fixp) { - if (TC_FORCE_RELOCATION_LOCAL (fixp)) - return FALSE; - - if (fixp->fx_r_type == BFD_RELOC_VTABLE_INHERIT - || fixp->fx_r_type == BFD_RELOC_VTABLE_ENTRY) + if (fixp->fx_pcrel) + { + if (TC_FORCE_RELOCATION_LOCAL (fixp)) + return FALSE; + } + /* Non-relative relocs can (and must) be adjusted if they do + not meet the criteria below, or the generic criteria. */ + else if (TC_FORCE_RELOCATION (fixp)) return FALSE; /* Do not adjust relocations involving symbols in code sections, @@ -2395,8 +2397,9 @@ mn10300_fix_adjustable (struct fix *fixp) symbols, because they too break relaxation. We do want to adjust other mergable symbols, like .rodata, because code relaxations need section-relative symbols to properly relax them. */ - if (! (S_GET_SEGMENT(fixp->fx_addsy)->flags & SEC_MERGE)) + if (! (S_GET_SEGMENT (fixp->fx_addsy)->flags & SEC_MERGE)) return FALSE; + if (strncmp (S_GET_SEGMENT (fixp->fx_addsy)->name, ".debug", 6) == 0) return FALSE; @@ -2502,3 +2505,60 @@ const pseudo_typeS md_pseudo_table[] = { "mn10300", set_arch_mach, MN103 }, {NULL, 0, 0} }; + +/* Returns FALSE if there is some mn10300 specific reason why the + subtraction of two same-section symbols cannot be computed by + the assembler. */ + +bfd_boolean +mn10300_allow_local_subtract (expressionS * left, expressionS * right, segT section) +{ + bfd_boolean result; + fragS * left_frag; + fragS * right_frag; + fragS * frag; + + /* If we are not performing linker relaxation then we have nothing + to worry about. */ + if (linkrelax == 0) + return TRUE; + + /* If the symbols are not in a code section then they are OK. */ + if ((section->flags & SEC_CODE) == 0) + return TRUE; + + /* Otherwise we have to scan the fragments between the two symbols. + If any instructions are found then we have to assume that linker + relaxation may change their size and so we must delay resolving + the subtraction until the final link. */ + left_frag = symbol_get_frag (left->X_add_symbol); + right_frag = symbol_get_frag (right->X_add_symbol); + + if (left_frag == right_frag) + return ! left_frag->tc_frag_data; + + result = TRUE; + for (frag = left_frag; frag != NULL; frag = frag->fr_next) + { + if (frag->tc_frag_data) + result = FALSE; + if (frag == right_frag) + break; + } + + if (frag == NULL) + for (frag = right_frag; frag != NULL; frag = frag->fr_next) + { + if (frag->tc_frag_data) + result = FALSE; + if (frag == left_frag) + break; + } + + if (frag == NULL) + /* The two symbols are on disjoint fragment chains + - we cannot possibly compute their difference. */ + return FALSE; + + return result; +} |