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authorRichard Henderson <rth@redhat.com>1999-05-03 07:29:11 +0000
committerRichard Henderson <rth@redhat.com>1999-05-03 07:29:11 +0000
commit252b5132c753830d5fd56823373aed85f2a0db63 (patch)
tree1af963bfd8d3e55167b81def4207f175eaff3a56 /gas/frags.c
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19990502 sourceware importbinu_ss_19990502
Diffstat (limited to 'gas/frags.c')
-rw-r--r--gas/frags.c359
1 files changed, 359 insertions, 0 deletions
diff --git a/gas/frags.c b/gas/frags.c
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--- /dev/null
+++ b/gas/frags.c
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+/* frags.c - manage frags -
+ Copyright (C) 1987, 90, 91, 92, 93, 94, 95, 96, 97, 1998
+ Free Software Foundation, Inc.
+
+ This file is part of GAS, the GNU Assembler.
+
+ GAS is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2, or (at your option)
+ any later version.
+
+ GAS is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with GAS; see the file COPYING. If not, write to the Free
+ Software Foundation, 59 Temple Place - Suite 330, Boston, MA
+ 02111-1307, USA. */
+
+#include "as.h"
+#include "subsegs.h"
+#include "obstack.h"
+
+extern fragS zero_address_frag;
+extern fragS bss_address_frag;
+
+/* Initialization for frag routines. */
+void
+frag_init ()
+{
+ zero_address_frag.fr_type = rs_fill;
+ bss_address_frag.fr_type = rs_fill;
+}
+
+/* Allocate a frag on the specified obstack.
+ Call this routine from everywhere else, so that all the weird alignment
+ hackery can be done in just one place. */
+fragS *
+frag_alloc (ob)
+ struct obstack *ob;
+{
+ fragS *ptr;
+ int oalign;
+
+ (void) obstack_alloc (ob, 0);
+ oalign = obstack_alignment_mask (ob);
+ obstack_alignment_mask (ob) = 0;
+ ptr = (fragS *) obstack_alloc (ob, SIZEOF_STRUCT_FRAG);
+ obstack_alignment_mask (ob) = oalign;
+ memset (ptr, 0, SIZEOF_STRUCT_FRAG);
+ return ptr;
+}
+
+/*
+ * frag_grow()
+ *
+ * Try to augment current frag by nchars chars.
+ * If there is no room, close of the current frag with a ".fill 0"
+ * and begin a new frag. Unless the new frag has nchars chars available
+ * do not return. Do not set up any fields of *now_frag.
+ */
+void
+frag_grow (nchars)
+ unsigned int nchars;
+{
+ if (obstack_room (&frchain_now->frch_obstack) < nchars)
+ {
+ unsigned int n;
+ long oldc;
+
+ frag_wane (frag_now);
+ frag_new (0);
+ oldc = frchain_now->frch_obstack.chunk_size;
+ frchain_now->frch_obstack.chunk_size = 2 * nchars + SIZEOF_STRUCT_FRAG;
+ while ((n = obstack_room (&frchain_now->frch_obstack)) < nchars)
+ {
+ frag_wane (frag_now);
+ frag_new (0);
+ }
+ frchain_now->frch_obstack.chunk_size = oldc;
+ }
+ if (obstack_room (&frchain_now->frch_obstack) < nchars)
+ as_fatal (_("Can't extend frag %d. chars"), nchars);
+}
+
+/*
+ * frag_new()
+ *
+ * Call this to close off a completed frag, and start up a new (empty)
+ * frag, in the same subsegment as the old frag.
+ * [frchain_now remains the same but frag_now is updated.]
+ * Because this calculates the correct value of fr_fix by
+ * looking at the obstack 'frags', it needs to know how many
+ * characters at the end of the old frag belong to (the maximal)
+ * fr_var: the rest must belong to fr_fix.
+ * It doesn't actually set up the old frag's fr_var: you may have
+ * set fr_var == 1, but allocated 10 chars to the end of the frag:
+ * in this case you pass old_frags_var_max_size == 10.
+ *
+ * Make a new frag, initialising some components. Link new frag at end
+ * of frchain_now.
+ */
+void
+frag_new (old_frags_var_max_size)
+ /* Number of chars (already allocated on obstack frags) in
+ variable_length part of frag. */
+ int old_frags_var_max_size;
+{
+ fragS *former_last_fragP;
+ frchainS *frchP;
+
+ assert (frchain_now->frch_last == frag_now);
+
+ /* Fix up old frag's fr_fix. */
+ frag_now->fr_fix = frag_now_fix () - old_frags_var_max_size;
+ /* Make sure its type is valid. */
+ assert (frag_now->fr_type != 0);
+
+ /* This will align the obstack so the next struct we allocate on it
+ will begin at a correct boundary. */
+ obstack_finish (&frchain_now->frch_obstack);
+ frchP = frchain_now;
+ know (frchP);
+ former_last_fragP = frchP->frch_last;
+ assert (former_last_fragP != 0);
+ assert (former_last_fragP == frag_now);
+ frag_now = frag_alloc (&frchP->frch_obstack);
+
+ as_where (&frag_now->fr_file, &frag_now->fr_line);
+
+ /* Generally, frag_now->points to an address rounded up to next
+ alignment. However, characters will add to obstack frags
+ IMMEDIATELY after the struct frag, even if they are not starting
+ at an alignment address. */
+ former_last_fragP->fr_next = frag_now;
+ frchP->frch_last = frag_now;
+
+#ifndef NO_LISTING
+ {
+ extern struct list_info_struct *listing_tail;
+ frag_now->line = listing_tail;
+ }
+#endif
+
+ assert (frchain_now->frch_last == frag_now);
+
+ frag_now->fr_next = NULL;
+} /* frag_new() */
+
+/*
+ * frag_more()
+ *
+ * Start a new frag unless we have n more chars of room in the current frag.
+ * Close off the old frag with a .fill 0.
+ *
+ * Return the address of the 1st char to write into. Advance
+ * frag_now_growth past the new chars.
+ */
+
+char *
+frag_more (nchars)
+ int nchars;
+{
+ register char *retval;
+
+ if (now_seg == absolute_section)
+ {
+ as_bad (_("attempt to allocate data in absolute section"));
+ subseg_set (text_section, 0);
+ }
+
+ if (mri_common_symbol != NULL)
+ {
+ as_bad (_("attempt to allocate data in common section"));
+ mri_common_symbol = NULL;
+ }
+
+ frag_grow (nchars);
+ retval = obstack_next_free (&frchain_now->frch_obstack);
+ obstack_blank_fast (&frchain_now->frch_obstack, nchars);
+ return (retval);
+} /* frag_more() */
+
+/*
+ * frag_var()
+ *
+ * Start a new frag unless we have max_chars more chars of room in the current frag.
+ * Close off the old frag with a .fill 0.
+ *
+ * Set up a machine_dependent relaxable frag, then start a new frag.
+ * Return the address of the 1st char of the var part of the old frag
+ * to write into.
+ */
+
+char *
+frag_var (type, max_chars, var, subtype, symbol, offset, opcode)
+ relax_stateT type;
+ int max_chars;
+ int var;
+ relax_substateT subtype;
+ symbolS *symbol;
+ offsetT offset;
+ char *opcode;
+{
+ register char *retval;
+
+ frag_grow (max_chars);
+ retval = obstack_next_free (&frchain_now->frch_obstack);
+ obstack_blank_fast (&frchain_now->frch_obstack, max_chars);
+ frag_now->fr_var = var;
+ frag_now->fr_type = type;
+ frag_now->fr_subtype = subtype;
+ frag_now->fr_symbol = symbol;
+ frag_now->fr_offset = offset;
+ frag_now->fr_opcode = opcode;
+#ifdef USING_CGEN
+ frag_now->fr_cgen.insn = 0;
+ frag_now->fr_cgen.opindex = 0;
+ frag_now->fr_cgen.opinfo = 0;
+#endif
+#ifdef TC_FRAG_INIT
+ TC_FRAG_INIT (frag_now);
+#endif
+ as_where (&frag_now->fr_file, &frag_now->fr_line);
+ frag_new (max_chars);
+ return (retval);
+}
+
+/*
+ * frag_variant()
+ *
+ * OVE: This variant of frag_var assumes that space for the tail has been
+ * allocated by caller.
+ * No call to frag_grow is done.
+ */
+
+char *
+frag_variant (type, max_chars, var, subtype, symbol, offset, opcode)
+ relax_stateT type;
+ int max_chars;
+ int var;
+ relax_substateT subtype;
+ symbolS *symbol;
+ offsetT offset;
+ char *opcode;
+{
+ register char *retval;
+
+ retval = obstack_next_free (&frchain_now->frch_obstack);
+ frag_now->fr_var = var;
+ frag_now->fr_type = type;
+ frag_now->fr_subtype = subtype;
+ frag_now->fr_symbol = symbol;
+ frag_now->fr_offset = offset;
+ frag_now->fr_opcode = opcode;
+#ifdef USING_CGEN
+ frag_now->fr_cgen.insn = 0;
+ frag_now->fr_cgen.opindex = 0;
+ frag_now->fr_cgen.opinfo = 0;
+#endif
+#ifdef TC_FRAG_INIT
+ TC_FRAG_INIT (frag_now);
+#endif
+ as_where (&frag_now->fr_file, &frag_now->fr_line);
+ frag_new (max_chars);
+ return (retval);
+} /* frag_variant() */
+
+/*
+ * frag_wane()
+ *
+ * Reduce the variable end of a frag to a harmless state.
+ */
+void
+frag_wane (fragP)
+ register fragS *fragP;
+{
+ fragP->fr_type = rs_fill;
+ fragP->fr_offset = 0;
+ fragP->fr_var = 0;
+}
+
+/* Make an alignment frag. The size of this frag will be adjusted to
+ force the next frag to have the appropriate alignment. ALIGNMENT
+ is the power of two to which to align. FILL_CHARACTER is the
+ character to use to fill in any bytes which are skipped. MAX is
+ the maximum number of characters to skip when doing the alignment,
+ or 0 if there is no maximum. */
+
+void
+frag_align (alignment, fill_character, max)
+ int alignment;
+ int fill_character;
+ int max;
+{
+ if (now_seg == absolute_section)
+ {
+ addressT new_off;
+
+ new_off = ((abs_section_offset + alignment - 1)
+ &~ ((1 << alignment) - 1));
+ if (max == 0 || new_off - abs_section_offset <= (addressT) max)
+ abs_section_offset = new_off;
+ }
+ else
+ {
+ char *p;
+
+ p = frag_var (rs_align, 1, 1, (relax_substateT) max,
+ (symbolS *) 0, (offsetT) alignment, (char *) 0);
+ *p = fill_character;
+ }
+}
+
+/* Make an alignment frag like frag_align, but fill with a repeating
+ pattern rather than a single byte. ALIGNMENT is the power of two
+ to which to align. FILL_PATTERN is the fill pattern to repeat in
+ the bytes which are skipped. N_FILL is the number of bytes in
+ FILL_PATTERN. MAX is the maximum number of characters to skip when
+ doing the alignment, or 0 if there is no maximum. */
+
+void
+frag_align_pattern (alignment, fill_pattern, n_fill, max)
+ int alignment;
+ const char *fill_pattern;
+ int n_fill;
+ int max;
+{
+ char *p;
+
+ p = frag_var (rs_align, n_fill, n_fill, (relax_substateT) max,
+ (symbolS *) 0, (offsetT) alignment, (char *) 0);
+ memcpy (p, fill_pattern, n_fill);
+}
+
+addressT
+frag_now_fix ()
+{
+ if (now_seg == absolute_section)
+ return abs_section_offset;
+ return (addressT) ((char*) obstack_next_free (&frchain_now->frch_obstack)
+ - frag_now->fr_literal);
+}
+
+void
+frag_append_1_char (datum)
+ int datum;
+{
+ if (obstack_room (&frchain_now->frch_obstack) <= 1)
+ {
+ frag_wane (frag_now);
+ frag_new (0);
+ }
+ obstack_1grow (&frchain_now->frch_obstack, datum);
+}
+
+/* end of frags.c */