aboutsummaryrefslogtreecommitdiff
path: root/gas/cgen.c
diff options
context:
space:
mode:
authorDave Brolley <brolley@redhat.com>2007-02-05 20:10:25 +0000
committerDave Brolley <brolley@redhat.com>2007-02-05 20:10:25 +0000
commit280d71bf40a544853567763c706e03334d6fd950 (patch)
treebba086524f3234ef357fe8beb0ce2d80a3aa8af4 /gas/cgen.c
parentbd2f2e55ad54541340e5ea415f1aba65aa80717e (diff)
downloadgdb-280d71bf40a544853567763c706e03334d6fd950.zip
gdb-280d71bf40a544853567763c706e03334d6fd950.tar.gz
gdb-280d71bf40a544853567763c706e03334d6fd950.tar.bz2
Support for Toshiba MeP and for complex relocations.
Diffstat (limited to 'gas/cgen.c')
-rw-r--r--gas/cgen.c327
1 files changed, 326 insertions, 1 deletions
diff --git a/gas/cgen.c b/gas/cgen.c
index 5a53789..5b0694b 100644
--- a/gas/cgen.c
+++ b/gas/cgen.c
@@ -26,6 +26,27 @@
#include "cgen.h"
#include "dwarf2dbg.h"
+#include "symbols.h"
+#include "struc-symbol.h"
+
+#ifdef OBJ_COMPLEX_RELC
+static expressionS * make_right_shifted_expr
+ (expressionS *, const int, const int);
+
+static unsigned long gas_cgen_encode_addend
+ (const unsigned long, const unsigned long, const unsigned long, \
+ const unsigned long, const unsigned long, const unsigned long, \
+ const unsigned long);
+
+static char * weak_operand_overflow_check
+ (const expressionS *, const CGEN_OPERAND *);
+
+static void queue_fixup_recursively
+ (const int, const int, expressionS *, \
+ const CGEN_MAYBE_MULTI_IFLD *, const int, const int);
+
+static int rightshift = 0;
+#endif
static void queue_fixup (int, int, expressionS *);
/* Opcode table descriptor, must be set by md_begin. */
@@ -63,6 +84,8 @@ struct fixup
int opindex;
int opinfo;
expressionS exp;
+ struct cgen_maybe_multi_ifield * field;
+ int msb_field_p;
};
static struct fixup fixups[GAS_CGEN_MAX_FIXUPS];
@@ -246,6 +269,8 @@ gas_cgen_record_fixup (frag, where, insn, length, operand, opinfo, symbol, offse
+ (int) operand->type));
fixP->fx_cgen.insn = insn;
fixP->fx_cgen.opinfo = opinfo;
+ fixP->fx_cgen.field = NULL;
+ fixP->fx_cgen.msb_field_p = 0;
return fixP;
}
@@ -284,10 +309,26 @@ gas_cgen_record_fixup_exp (frag, where, insn, length, operand, opinfo, exp)
+ (int) operand->type));
fixP->fx_cgen.insn = insn;
fixP->fx_cgen.opinfo = opinfo;
+ fixP->fx_cgen.field = NULL;
+ fixP->fx_cgen.msb_field_p = 0;
return fixP;
}
+#ifdef OBJ_COMPLEX_RELC
+static symbolS *
+expr_build_binary (operatorT op, symbolS * s1, symbolS * s2)
+{
+ expressionS e;
+
+ e.X_op = op;
+ e.X_add_symbol = s1;
+ e.X_op_symbol = s2;
+ e.X_add_number = 0;
+ return make_expr_symbol (& e);
+}
+#endif
+
/* Used for communication between the next two procedures. */
static jmp_buf expr_jmp_buf;
static int expr_jmp_buf_p;
@@ -305,7 +346,12 @@ static int expr_jmp_buf_p;
const char *
gas_cgen_parse_operand (cd, want, strP, opindex, opinfo, resultP, valueP)
+
+#ifdef OBJ_COMPLEX_RELC
+ CGEN_CPU_DESC cd;
+#else
CGEN_CPU_DESC cd ATTRIBUTE_UNUSED;
+#endif
enum cgen_parse_operand_type want;
const char **strP;
int opindex;
@@ -326,6 +372,13 @@ gas_cgen_parse_operand (cd, want, strP, opindex, opinfo, resultP, valueP)
const char *errmsg;
expressionS exp;
+#ifdef OBJ_COMPLEX_RELC
+ volatile int signed_p = 0;
+ symbolS * stmp = NULL;
+ bfd_reloc_code_real_type reloc_type;
+ const CGEN_OPERAND * operand;
+ fixS dummy_fixup;
+#endif
if (want == CGEN_PARSE_OPERAND_INIT)
{
gas_cgen_init_parse ();
@@ -383,9 +436,82 @@ gas_cgen_parse_operand (cd, want, strP, opindex, opinfo, resultP, valueP)
break;
de_fault:
default:
+#ifdef OBJ_COMPLEX_RELC
+ /* Look up operand, check to see if there's an obvious
+ overflow (this helps disambiguate some insn parses). */
+ operand = cgen_operand_lookup_by_num (cd, opindex);
+ errmsg = weak_operand_overflow_check (& exp, operand);
+
+ if (! errmsg)
+ {
+ /* Fragment the expression as necessary, and queue a reloc. */
+ memset (& dummy_fixup, 0, sizeof (fixS));
+
+ reloc_type = md_cgen_lookup_reloc (0, operand, & dummy_fixup);
+
+ if (exp.X_op == O_symbol
+ && reloc_type == BFD_RELOC_RELC
+ && exp.X_add_symbol->sy_value.X_op == O_constant
+ && exp.X_add_symbol->bsym->section != expr_section
+ && exp.X_add_symbol->bsym->section != absolute_section
+ && exp.X_add_symbol->bsym->section != undefined_section)
+ {
+ /* Local labels will have been (eagerly) turned into constants
+ by now, due to the inappropriately deep insight of the
+ expression parser. Unfortunately make_expr_symbol
+ prematurely dives into the symbol evaluator, and in this
+ case it gets a bad answer, so we manually create the
+ expression symbol we want here. */
+ stmp = symbol_create (FAKE_LABEL_NAME, expr_section, 0,
+ & zero_address_frag);
+ symbol_set_value_expression (stmp, & exp);
+ }
+ else
+ stmp = make_expr_symbol (& exp);
+
+ /* If this is a pc-relative RELC operand, we
+ need to subtract "." from the expression. */
+ if (reloc_type == BFD_RELOC_RELC
+ && CGEN_OPERAND_ATTR_VALUE (operand, CGEN_OPERAND_PCREL_ADDR))
+ stmp = expr_build_binary (O_subtract, stmp, expr_build_dot ());
+
+ /* FIXME: this is not a perfect heuristic for figuring out
+ whether an operand is signed: it only works when the operand
+ is an immediate. it's not terribly likely that any other
+ values will be signed relocs, but it's possible. */
+ if (operand && (operand->hw_type == HW_H_SINT))
+ signed_p = 1;
+
+ if (stmp->bsym && (stmp->bsym->section == expr_section))
+ {
+ if (signed_p)
+ stmp->bsym->flags |= BSF_SRELC;
+ else
+ stmp->bsym->flags |= BSF_RELC;
+ }
+
+ /* Now package it all up for the fixup emitter. */
+ exp.X_op = O_symbol;
+ exp.X_op_symbol = 0;
+ exp.X_add_symbol = stmp;
+ exp.X_add_number = 0;
+
+ /* Re-init rightshift quantity, just in case. */
+ rightshift = operand->length;
+ queue_fixup_recursively (opindex, opinfo_1, & exp,
+ (reloc_type == BFD_RELOC_RELC) ?
+ & (operand->index_fields) : 0,
+ signed_p, -1);
+ }
+ * resultP = errmsg
+ ? CGEN_PARSE_OPERAND_RESULT_ERROR
+ : CGEN_PARSE_OPERAND_RESULT_QUEUED;
+ *valueP = 0;
+#else
queue_fixup (opindex, opinfo_1, &exp);
*valueP = 0;
*resultP = CGEN_PARSE_OPERAND_RESULT_QUEUED;
+#endif
break;
}
@@ -553,6 +679,8 @@ gas_cgen_finish_insn (insn, buf, length, relax_p, result)
insn, length, operand,
fixups[i].opinfo,
&fixups[i].exp);
+ fixP->fx_cgen.field = fixups[i].field;
+ fixP->fx_cgen.msb_field_p = fixups[i].msb_field_p;
if (result)
result->fixups[i] = fixP;
}
@@ -564,6 +692,167 @@ gas_cgen_finish_insn (insn, buf, length, relax_p, result)
}
}
+#ifdef OBJ_COMPLEX_RELC
+/* Queue many fixups, recursively. If the field is a multi-ifield,
+ repeatedly queue its sub-parts, right shifted to fit into the field (we
+ assume here multi-fields represent a left-to-right, MSB0-LSB0
+ reading). */
+
+static void
+queue_fixup_recursively (const int opindex,
+ const int opinfo,
+ expressionS * expP,
+ const CGEN_MAYBE_MULTI_IFLD * field,
+ const int signed_p,
+ const int part_of_multi)
+{
+ if (field && field->count)
+ {
+ int i;
+
+ for (i = 0; i < field->count; ++ i)
+ queue_fixup_recursively (opindex, opinfo, expP,
+ & (field->val.multi[i]), signed_p, i);
+ }
+ else
+ {
+ expressionS * new_exp = expP;
+
+#ifdef DEBUG
+ printf ("queueing fixup for field %s\n",
+ (field ? field->val.leaf->name : "??"));
+ print_symbol_value (expP->X_add_symbol);
+#endif
+ if (field && part_of_multi != -1)
+ {
+ rightshift -= field->val.leaf->length;
+
+ /* Shift reloc value by number of bits remaining after this
+ field. */
+ if (rightshift)
+ new_exp = make_right_shifted_expr (expP, rightshift, signed_p);
+ }
+
+ /* Truncate reloc values to length, *after* leftmost one. */
+ fixups[num_fixups].msb_field_p = (part_of_multi <= 0);
+ fixups[num_fixups].field = (CGEN_MAYBE_MULTI_IFLD *) field;
+
+ queue_fixup (opindex, opinfo, new_exp);
+ }
+}
+
+/* Encode the self-describing RELC reloc format's addend. */
+
+static unsigned long
+gas_cgen_encode_addend (const unsigned long start, /* in bits */
+ const unsigned long len, /* in bits */
+ const unsigned long oplen, /* in bits */
+ const unsigned long wordsz, /* in bytes */
+ const unsigned long chunksz, /* in bytes */
+ const unsigned long signed_p,
+ const unsigned long trunc_p)
+{
+ unsigned long res = 0L;
+
+ res |= start & 0x3F;
+ res |= (oplen & 0x3F) << 6;
+ res |= (len & 0x3F) << 12;
+ res |= (wordsz & 0xF) << 18;
+ res |= (chunksz & 0xF) << 22;
+ res |= (CGEN_INSN_LSB0_P ? 1 : 0) << 27;
+ res |= signed_p << 28;
+ res |= trunc_p << 29;
+
+ return res;
+}
+
+/* Purpose: make a weak check that the expression doesn't overflow the
+ operand it's to be inserted into.
+
+ Rationale: some insns used to use %operators to disambiguate during a
+ parse. when these %operators are translated to expressions by the macro
+ expander, the ambiguity returns. we attempt to disambiguate by field
+ size.
+
+ Method: check to see if the expression's top node is an O_and operator,
+ and the mask is larger than the operand length. This would be an
+ overflow, so signal it by returning an error string. Any other case is
+ ambiguous, so we assume it's OK and return NULL. */
+
+static char *
+weak_operand_overflow_check (const expressionS * exp,
+ const CGEN_OPERAND * operand)
+{
+ const unsigned long len = operand->length;
+ unsigned long mask;
+ unsigned long opmask = (((1L << (len - 1)) - 1) << 1) | 1;
+
+ if (!exp)
+ return NULL;
+
+ if (exp->X_op != O_bit_and)
+ {
+ /* Check for implicit overflow flag. */
+ if (CGEN_OPERAND_ATTR_VALUE
+ (operand, CGEN_OPERAND_RELOC_IMPLIES_OVERFLOW))
+ return _("a reloc on this operand implies an overflow");
+ return NULL;
+ }
+
+ mask = exp->X_add_number;
+
+ if (exp->X_add_symbol &&
+ exp->X_add_symbol->sy_value.X_op == O_constant)
+ mask |= exp->X_add_symbol->sy_value.X_add_number;
+
+ if (exp->X_op_symbol &&
+ exp->X_op_symbol->sy_value.X_op == O_constant)
+ mask |= exp->X_op_symbol->sy_value.X_add_number;
+
+ /* Want to know if mask covers more bits than opmask.
+ this is the same as asking if mask has any bits not in opmask,
+ or whether (mask & ~opmask) is nonzero. */
+ if (mask && (mask & ~opmask))
+ {
+#ifdef DEBUG
+ printf ("overflow: (mask = %8.8x, ~opmask = %8.8x, AND = %8.8x)\n",
+ mask, ~opmask, (mask & ~opmask));
+#endif
+ return _("operand mask overflow");
+ }
+
+ return NULL;
+}
+
+
+static expressionS *
+make_right_shifted_expr (expressionS * exp,
+ const int amount,
+ const int signed_p)
+{
+ symbolS * stmp = 0;
+ expressionS * new_exp;
+
+ stmp = expr_build_binary (O_right_shift,
+ make_expr_symbol (exp),
+ expr_build_uconstant (amount));
+
+ if (signed_p)
+ stmp->bsym->flags |= BSF_SRELC;
+ else
+ stmp->bsym->flags |= BSF_RELC;
+
+ /* Then wrap that in a "symbol expr" for good measure. */
+ new_exp = xmalloc (sizeof (expressionS));
+ memset (new_exp, 0, sizeof (expressionS));
+ new_exp->X_op = O_symbol;
+ new_exp->X_op_symbol = 0;
+ new_exp->X_add_symbol = stmp;
+ new_exp->X_add_number = 0;
+
+ return new_exp;
+}
+#endif
/* Apply a fixup to the object code. This is called for all the
fixups we generated by the call to fix_new_exp, above. In the call
above we used a reloc code which was the largest legal reloc code
@@ -602,6 +891,30 @@ gas_cgen_md_apply_fix (fixP, valP, seg)
bfd_reloc_code_real_type reloc_type;
CGEN_FIELDS *fields = alloca (CGEN_CPU_SIZEOF_FIELDS (cd));
const CGEN_INSN *insn = fixP->fx_cgen.insn;
+ int start;
+ int length;
+ int signed_p = 0;
+
+ if (fixP->fx_cgen.field)
+ {
+ /* Use the twisty little pointer path
+ back to the ifield if it exists. */
+ start = fixP->fx_cgen.field->val.leaf->start;
+ length = fixP->fx_cgen.field->val.leaf->length;
+ }
+ else
+ {
+ /* Or the far less useful operand-size guesstimate. */
+ start = operand->start;
+ length = operand->length;
+ }
+
+ /* FIXME: this is not a perfect heuristic for figuring out
+ whether an operand is signed: it only works when the operand
+ is an immediate. it's not terribly likely that any other
+ values will be signed relocs, but it's possible. */
+ if (operand && (operand->hw_type == HW_H_SINT))
+ signed_p = 1;
/* If the reloc has been fully resolved finish the operand here. */
/* FIXME: This duplicates the capabilities of code in BFD. */
@@ -644,6 +957,18 @@ gas_cgen_md_apply_fix (fixP, valP, seg)
partial_inplace == false. */
reloc_type = md_cgen_lookup_reloc (insn, operand, fixP);
+#ifdef OBJ_COMPLEX_RELC
+ if (reloc_type == BFD_RELOC_RELC)
+ {
+ /* Change addend to "self-describing" form,
+ for BFD to handle in the linker. */
+ value = gas_cgen_encode_addend (start, operand->length,
+ length, fixP->fx_size,
+ cd->insn_chunk_bitsize / 8,
+ signed_p,
+ ! (fixP->fx_cgen.msb_field_p));
+ }
+#endif
if (reloc_type != BFD_RELOC_NONE)
fixP->fx_r_type = reloc_type;
@@ -699,7 +1024,6 @@ gas_cgen_tc_gen_reloc (section, fixP)
fixS * fixP;
{
arelent *reloc;
-
reloc = (arelent *) xmalloc (sizeof (arelent));
reloc->howto = bfd_reloc_type_lookup (stdoutput, fixP->fx_r_type);
@@ -737,3 +1061,4 @@ gas_cgen_begin ()
else
cgen_clear_signed_overflow_ok (gas_cgen_cpu_desc);
}
+