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authorAlexandre Oliva <aoliva@redhat.com>2000-09-02 02:36:27 +0000
committerAlexandre Oliva <aoliva@redhat.com>2000-09-02 02:36:27 +0000
commita1cc9221e2f5771188b5832633eb73ee2bbbb4c5 (patch)
tree7abae9229c83c3e90771b75ffeeff560c667c8c8
parent37c644f2f5e7b4dce05757b8cd5822f971f6d5d8 (diff)
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* config/tc-sh.h [OBJ_ELF] (TC_FIX_ADJUSTABLE): Define.
* config/tc-sh.c (md_apply_fix): Map 32-bit relocations that become PC-relative to BFD_RELOC_32_PCREL. Reject 16- or 8-bit similar relocs. (sh_obj_adjustable): Return 1 for PC-relative offsets used in branches. * config/tc-sh.h (DIFF_EXPR_OK, GLOBAL_OFFSET_TABLE_NAME, TC_RELOC_GLOBAL_OFFSET_TABLE, TC_RELOC_RTSYM_LOC_FIXUP): Define. * config/tc-sh.c (sh_elf_cons, sh_elf_suffix): New functions. [OBJ_ELF] (md_pseudo_table) <long, int, word, short>: Use them. (GOT_symbol): New variable. (md_undefined_symbol): Set it.
-rw-r--r--gas/ChangeLog18
-rw-r--r--gas/config/tc-sh.c299
-rw-r--r--gas/config/tc-sh.h40
3 files changed, 357 insertions, 0 deletions
diff --git a/gas/ChangeLog b/gas/ChangeLog
index b1df505..ba7429c 100644
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,3 +1,21 @@
+2000-09-01 Alexandre Oliva <aoliva@redhat.com>
+
+ * config/tc-sh.h [OBJ_ELF] (TC_FIX_ADJUSTABLE): Define.
+ * config/tc-sh.c (md_apply_fix): Map 32-bit relocations that
+ become PC-relative to BFD_RELOC_32_PCREL. Reject 16- or 8-bit
+ similar relocs.
+ (sh_obj_adjustable): Return 1 for PC-relative offsets used in
+ branches.
+
+2000-09-01 Niibe Yutaka <gniibe@m17n.org>, Kaz Kojima <kkojima@rr.iij4u.or.jp>, Alexandre Oliva <aoliva@redhat.com>
+
+ * config/tc-sh.h (DIFF_EXPR_OK, GLOBAL_OFFSET_TABLE_NAME,
+ TC_RELOC_GLOBAL_OFFSET_TABLE, TC_RELOC_RTSYM_LOC_FIXUP): Define.
+ * config/tc-sh.c (sh_elf_cons, sh_elf_suffix): New functions.
+ [OBJ_ELF] (md_pseudo_table) <long, int, word, short>: Use them.
+ (GOT_symbol): New variable.
+ (md_undefined_symbol): Set it.
+
2000-09-01 Richard Henderson <rth@cygnus.com>
* config/tc-ia64.c (match): Don't inline.
diff --git a/gas/config/tc-sh.c b/gas/config/tc-sh.c
index 8362896..a2cd7de 100644
--- a/gas/config/tc-sh.c
+++ b/gas/config/tc-sh.c
@@ -51,6 +51,12 @@ static void s_uacons PARAMS ((int));
static sh_opcode_info *find_cooked_opcode PARAMS ((char **));
static unsigned int assemble_ppi PARAMS ((char *, sh_opcode_info *));
+#ifdef OBJ_ELF
+static void sh_elf_cons PARAMS ((int));
+
+symbolS *GOT_symbol; /* Pre-defined "_GLOBAL_OFFSET_TABLE_" */
+#endif
+
int shl = 0;
static void
@@ -69,8 +75,15 @@ little (ignore)
const pseudo_typeS md_pseudo_table[] =
{
+#ifdef OBJ_ELF
+ {"long", sh_elf_cons, 4},
+ {"int", sh_elf_cons, 4},
+ {"word", sh_elf_cons, 2},
+ {"short", sh_elf_cons, 2},
+#else
{"int", cons, 4},
{"word", cons, 2},
+#endif /* OBJ_ELF */
{"form", listing_psize, 0},
{"little", little, 0},
{"heading", listing_title, 0},
@@ -200,6 +213,191 @@ const relax_typeS md_relax_table[C (END, 0)] = {
static struct hash_control *opcode_hash_control; /* Opcode mnemonics */
+
+#ifdef OBJ_ELF
+/* Parse @got, etc. and return the desired relocation.
+ If we have additional arithmetic expression, then we fill in new_exp_p. */
+static bfd_reloc_code_real_type
+sh_elf_suffix (str_p, exp_p, new_exp_p)
+ char **str_p;
+ expressionS *exp_p, *new_exp_p;
+{
+ struct map_bfd {
+ char *string;
+ int length;
+ bfd_reloc_code_real_type reloc;
+ };
+
+ char ident[20];
+ char *str = *str_p;
+ char *str2;
+ int ch;
+ int len;
+ struct map_bfd *ptr;
+
+#define MAP(str,reloc) { str, sizeof(str)-1, reloc }
+
+ static struct map_bfd mapping[] = {
+ MAP ("got", BFD_RELOC_32_GOT_PCREL),
+ MAP ("plt", BFD_RELOC_32_PLT_PCREL),
+ MAP ("gotoff", BFD_RELOC_32_GOTOFF),
+ { (char *)0, 0, BFD_RELOC_UNUSED }
+ };
+
+ if (*str++ != '@')
+ return BFD_RELOC_UNUSED;
+
+ for (ch = *str, str2 = ident;
+ (str2 < ident + sizeof (ident) - 1
+ && (isalnum (ch) || ch == '@'));
+ ch = *++str)
+ {
+ *str2++ = (islower (ch)) ? ch : tolower (ch);
+ }
+
+ *str2 = '\0';
+ len = str2 - ident;
+
+ ch = ident[0];
+ for (ptr = &mapping[0]; ptr->length > 0; ptr++)
+ if (ch == ptr->string[0]
+ && len == ptr->length
+ && memcmp (ident, ptr->string, ptr->length) == 0)
+ {
+ /* Now check for identifier@suffix+constant */
+ if (*str == '-' || *str == '+')
+ {
+ char *orig_line = input_line_pointer;
+
+ input_line_pointer = str;
+ expression (new_exp_p);
+ if (new_exp_p->X_op == O_constant)
+ {
+ exp_p->X_add_number += new_exp_p->X_add_number;
+ str = input_line_pointer;
+ }
+ if (new_exp_p->X_op == O_subtract)
+ str = input_line_pointer;
+
+ if (&input_line_pointer != str_p)
+ input_line_pointer = orig_line;
+ }
+
+ *str_p = str;
+ return ptr->reloc;
+ }
+
+ return BFD_RELOC_UNUSED;
+}
+
+/* The regular cons() function, that reads constants, doesn't support
+ suffixes such as @GOT, @GOTOFF and @PLT, that generate
+ machine-specific relocation types. So we must define it here. */
+/* Clobbers input_line_pointer, checks end-of-line. */
+static void
+sh_elf_cons (nbytes)
+ register int nbytes; /* 1=.byte, 2=.word, 4=.long */
+{
+ expressionS exp, new_exp;
+ bfd_reloc_code_real_type reloc;
+ const char *name;
+
+ if (is_it_end_of_statement ())
+ {
+ demand_empty_rest_of_line ();
+ return;
+ }
+
+ do
+ {
+ expression (&exp);
+ new_exp.X_op = O_absent;
+ new_exp.X_add_symbol = new_exp.X_op_symbol = NULL;
+ /* If the _GLOBAL_OFFSET_TABLE_ symbol hasn't been found yet,
+ use the name of the symbol to tell whether it's the
+ _GLOBAL_OFFSET_TABLE_. If it has, comparing the symbols is
+ sufficient. */
+ if (! GOT_symbol && exp.X_add_symbol)
+ name = S_GET_NAME (exp.X_add_symbol);
+ else
+ name = NULL;
+ /* Check whether this expression involves the
+ _GLOBAL_OFFSET_TABLE_ symbol, by itself or added to a
+ difference of two other symbols. */
+ if (((GOT_symbol && GOT_symbol == exp.X_add_symbol)
+ || (! GOT_symbol && name
+ && strcmp (name, GLOBAL_OFFSET_TABLE_NAME) == 0))
+ && (exp.X_op == O_symbol
+ || (exp.X_op == O_add
+ && ((symbol_get_value_expression (exp.X_op_symbol)->X_op)
+ == O_subtract))))
+ {
+ reloc_howto_type *reloc_howto = bfd_reloc_type_lookup (stdoutput,
+ BFD_RELOC_32);
+ int size = bfd_get_reloc_size (reloc_howto);
+
+ if (GOT_symbol == NULL)
+ GOT_symbol = symbol_find_or_make (GLOBAL_OFFSET_TABLE_NAME);
+
+ if (size > nbytes)
+ as_bad (_("%s relocations do not fit in %d bytes\n"),
+ reloc_howto->name, nbytes);
+ else
+ {
+ register char *p = frag_more ((int) nbytes);
+ int offset = nbytes - size;
+
+ fix_new_exp (frag_now, p - frag_now->fr_literal + offset,
+ size, &exp, 0, TC_RELOC_GLOBAL_OFFSET_TABLE);
+ }
+ }
+ /* Check if this symbol involves one of the magic suffixes, such
+ as @GOT, @GOTOFF or @PLT, and determine which relocation type
+ to use. */
+ else if ((exp.X_op == O_symbol || (exp.X_op == O_add && exp.X_op_symbol))
+ && *input_line_pointer == '@'
+ && ((reloc = sh_elf_suffix (&input_line_pointer, &exp, &new_exp))
+ != BFD_RELOC_UNUSED))
+ {
+ reloc_howto_type *reloc_howto = bfd_reloc_type_lookup (stdoutput,
+ reloc);
+ int size = bfd_get_reloc_size (reloc_howto);
+
+ /* Force a GOT to be generated. */
+ if (GOT_symbol == NULL)
+ GOT_symbol = symbol_find_or_make (GLOBAL_OFFSET_TABLE_NAME);
+
+ if (size > nbytes)
+ as_bad (_("%s relocations do not fit in %d bytes\n"),
+ reloc_howto->name, nbytes);
+ else
+ {
+ register char *p = frag_more ((int) nbytes);
+ int offset = nbytes - size;
+
+ fix_new_exp (frag_now, p - frag_now->fr_literal + offset, size,
+ &exp, 0, reloc);
+ if (new_exp.X_op != O_absent)
+ fix_new_exp (frag_now, p - frag_now->fr_literal + offset, size,
+ &new_exp, 0, BFD_RELOC_32);
+ }
+ }
+ else
+ emit_expr (&exp, (unsigned int) nbytes);
+ }
+ while (*input_line_pointer++ == ',');
+
+ input_line_pointer--; /* Put terminator back into stream. */
+ if (*input_line_pointer == '#' || *input_line_pointer == '!')
+ {
+ while (! is_end_of_line[*input_line_pointer++]);
+ }
+ else
+ demand_empty_rest_of_line ();
+}
+#endif /* OBJ_ELF */
+
+
/* This function is called once, at assembler startup time. This should
set up all the tables, etc that the MD part of the assembler needs. */
@@ -1795,6 +1993,24 @@ symbolS *
md_undefined_symbol (name)
char *name;
{
+#ifdef OBJ_ELF
+ /* Under ELF we need to default _GLOBAL_OFFSET_TABLE. Otherwise we
+ have no need to default values of symbols. */
+ if (strcmp (name, GLOBAL_OFFSET_TABLE_NAME) == 0)
+ {
+ if (!GOT_symbol)
+ {
+ if (symbol_find (name))
+ as_bad ("GOT already in the symbol table");
+
+ GOT_symbol = symbol_new (name, undefined_section,
+ (valueT)0, & zero_address_frag);
+ }
+
+ return GOT_symbol;
+ }
+#endif /* OBJ_ELF */
+
return 0;
}
@@ -2544,6 +2760,20 @@ sh_fix_adjustable (fixP)
if (fixP->fx_addsy == NULL)
return 1;
+ if (fixP->fx_r_type == BFD_RELOC_SH_PCDISP8BY2
+ || fixP->fx_r_type == BFD_RELOC_SH_PCDISP12BY2
+ || fixP->fx_r_type == BFD_RELOC_SH_PCRELIMM8BY2
+ || fixP->fx_r_type == BFD_RELOC_SH_PCRELIMM8BY4
+ || fixP->fx_r_type == BFD_RELOC_8_PCREL
+ || fixP->fx_r_type == BFD_RELOC_SH_SWITCH16
+ || fixP->fx_r_type == BFD_RELOC_SH_SWITCH32)
+ return 1;
+
+ if (! TC_RELOC_RTSYM_LOC_FIXUP (fixP)
+ || fixP->fx_r_type == BFD_RELOC_32_GOTOFF
+ || fixP->fx_r_type == BFD_RELOC_RVA)
+ return 0;
+
/* We need the symbol name for the VTABLE entries */
if (fixP->fx_r_type == BFD_RELOC_VTABLE_INHERIT
|| fixP->fx_r_type == BFD_RELOC_VTABLE_ENTRY)
@@ -2605,6 +2835,35 @@ md_apply_fix (fixP, val)
int shift;
#ifdef BFD_ASSEMBLER
+ /* A difference between two symbols, the second of which is in the
+ current section, is transformed in a PC-relative relocation to
+ the other symbol. We have to adjust the relocation type here. */
+ if (fixP->fx_pcrel)
+ {
+ switch (fixP->fx_r_type)
+ {
+ default:
+ break;
+
+ case BFD_RELOC_32:
+ fixP->fx_r_type = BFD_RELOC_32_PCREL;
+ break;
+
+ /* Currently, we only support 32-bit PCREL relocations.
+ We'd need a new reloc type to handle 16_PCREL, and
+ 8_PCREL is already taken for R_SH_SWITCH8, which
+ apparently does something completely different than what
+ we need. FIXME. */
+ case BFD_RELOC_16:
+ bfd_set_error (bfd_error_bad_value);
+ return false;
+
+ case BFD_RELOC_8:
+ bfd_set_error (bfd_error_bad_value);
+ return false;
+ }
+ }
+
/* The function adjust_reloc_syms won't convert a reloc against a weak
symbol into a reloc against a section, but bfd_install_relocation
will screw up if the symbol is defined, so we have to adjust val here
@@ -2715,6 +2974,7 @@ md_apply_fix (fixP, val)
break;
case BFD_RELOC_32:
+ case BFD_RELOC_32_PCREL:
md_number_to_chars (buf, val, 4);
break;
@@ -2747,6 +3007,43 @@ md_apply_fix (fixP, val)
return;
#endif
+#ifdef OBJ_ELF
+ case BFD_RELOC_32_PLT_PCREL:
+ /* Make the jump instruction point to the address of the operand. At
+ runtime we merely add the offset to the actual PLT entry. */
+ *valp = 0xfffffffc;
+ break;
+
+ case BFD_RELOC_SH_GOTPC:
+ /* This is tough to explain. We end up with this one if we have
+ operands that look like "_GLOBAL_OFFSET_TABLE_+[.-.L284]".
+ The goal here is to obtain the absolute address of the GOT,
+ and it is strongly preferable from a performance point of
+ view to avoid using a runtime relocation for this. There are
+ cases where you have something like:
+
+ .long _GLOBAL_OFFSET_TABLE_+[.-.L66]
+
+ and here no correction would be required. Internally in the
+ assembler we treat operands of this form as not being pcrel
+ since the '.' is explicitly mentioned, and I wonder whether
+ it would simplify matters to do it this way. Who knows. In
+ earlier versions of the PIC patches, the pcrel_adjust field
+ was used to store the correction, but since the expression is
+ not pcrel, I felt it would be confusing to do it this way. */
+ *valp -= 1;
+ md_number_to_chars (buf, val, 4);
+ break;
+
+ case BFD_RELOC_32_GOT_PCREL:
+ *valp = 0; /* Fully resolved at runtime. No addend. */
+ md_number_to_chars (buf, 0, 4);
+ break;
+
+ case BFD_RELOC_32_GOTOFF:
+ break;
+#endif
+
default:
abort ();
}
@@ -3098,6 +3395,8 @@ tc_gen_reloc (section, fixp)
}
else if (fixp->fx_pcrel)
rel->addend = fixp->fx_addnumber;
+ else if (r_type == BFD_RELOC_32 || r_type == BFD_RELOC_32_GOTOFF)
+ rel->addend = fixp->fx_addnumber;
else
rel->addend = 0;
diff --git a/gas/config/tc-sh.h b/gas/config/tc-sh.h
index 4e73b8b..54ba1b9 100644
--- a/gas/config/tc-sh.h
+++ b/gas/config/tc-sh.h
@@ -61,6 +61,10 @@ extern int sh_force_relocation ();
#define obj_fix_adjustable(fixP) sh_fix_adjustable(fixP)
struct fix;
extern boolean sh_fix_adjustable PARAMS ((struct fix *));
+
+/* This arranges for gas/write.c to not apply a relocation if
+ obj_fix_adjustable() says it is not adjustable. */
+#define TC_FIX_ADJUSTABLE(fixP) obj_fix_adjustable (fixP)
#endif
#define IGNORE_NONSTANDARD_ESCAPES
@@ -161,6 +165,42 @@ extern int target_big_endian;
#define elf_tc_final_processing sh_elf_final_processing
extern void sh_elf_final_processing PARAMS ((void));
+#define DIFF_EXPR_OK /* foo-. gets turned into PC relative relocs */
+
+#define GLOBAL_OFFSET_TABLE_NAME "_GLOBAL_OFFSET_TABLE_"
+
+/* This is the relocation type for direct references to
+ GLOBAL_OFFSET_TABLE. It comes up in complicated expressions such
+ as _GLOBAL_OFFSET_TABLE_+[.-.L284], which cannot be expressed
+ normally with the regular expressions. The fixup specified here
+ when used at runtime implies that we should add the address of the
+ GOT to the specified location, and as a result we have simplified
+ the expression into something we can use. */
+#define TC_RELOC_GLOBAL_OFFSET_TABLE BFD_RELOC_SH_GOTPC
+
+/* This expression evaluates to false if the relocation is for a local object
+ for which we still want to do the relocation at runtime. True if we
+ are willing to perform this relocation while building the .o file.
+ This is only used for pcrel relocations, so GOTOFF does not need to be
+ checked here. I am not sure if some of the others are ever used with
+ pcrel, but it is easier to be safe than sorry.
+
+ We can't resolve references to the GOT or the PLT when creating the
+ object file, since these tables are only created by the linker.
+ Also, if the symbol is global, weak, common or not defined, the
+ assembler can't compute the appropriate reloc, since its location
+ can only be determined at link time. */
+
+#define TC_RELOC_RTSYM_LOC_FIXUP(FIX) \
+ ((FIX)->fx_r_type != BFD_RELOC_32_PLT_PCREL \
+ && (FIX)->fx_r_type != BFD_RELOC_32_GOT_PCREL \
+ && (FIX)->fx_r_type != BFD_RELOC_SH_GOTPC \
+ && ((FIX)->fx_addsy == NULL \
+ || (! S_IS_EXTERNAL ((FIX)->fx_addsy) \
+ && ! S_IS_WEAK ((FIX)->fx_addsy) \
+ && S_IS_DEFINED ((FIX)->fx_addsy) \
+ && ! S_IS_COMMON ((FIX)->fx_addsy))))
+
#endif /* OBJ_ELF */
#define md_end() sh_finalize ()