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authorBob Wilson <bob.wilson@acm.org>2006-08-08 19:09:34 +0000
committerBob Wilson <bob.wilson@acm.org>2006-08-08 19:09:34 +0000
commit1737851b2005af535e44e89a4e7f341eddddd0f0 (patch)
tree1850d29d718572eef76e443b68821f232ff3a36b /gas/dwarf2dbg.c
parentce928021ab9b37594f8caa625b84783793ee5095 (diff)
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gas/ChangeLog:
* dwarf2dbg.c (DWARF2_USE_FIXED_ADVANCE_PC): New. (out_sleb128): New. (out_fixed_inc_line_addr): New. (process_entries): Use out_fixed_inc_line_addr when DWARF2_USE_FIXED_ADVANCE_PC is set. * config/tc-xtensa.h (DWARF2_USE_FIXED_ADVANCE_PC): Define. gas/testsuite/ChangeLog: * gas/lns/lns-common-1-alt.d: New file. * gas/lns/lns.exp: Use lns-common-1-alt.d for xtensa targets.
Diffstat (limited to 'gas/dwarf2dbg.c')
-rw-r--r--gas/dwarf2dbg.c65
1 files changed, 64 insertions, 1 deletions
diff --git a/gas/dwarf2dbg.c b/gas/dwarf2dbg.c
index 22dde6a..eb9584b 100644
--- a/gas/dwarf2dbg.c
+++ b/gas/dwarf2dbg.c
@@ -88,6 +88,13 @@
#define DL_FILES 1
#define DL_BODY 2
+/* If linker relaxation might change offsets in the code, the DWARF special
+ opcodes and variable-length operands cannot be used. If this macro is
+ nonzero, use the DW_LNS_fixed_advance_pc opcode instead. */
+#ifndef DWARF2_USE_FIXED_ADVANCE_PC
+# define DWARF2_USE_FIXED_ADVANCE_PC 0
+#endif
+
/* First special line opcde - leave room for the standard opcodes.
Note: If you want to change this, you'll have to update the
"standard_opcode_lengths" table that is emitted below in
@@ -191,11 +198,13 @@ static void out_two (int);
static void out_four (int);
static void out_abbrev (int, int);
static void out_uleb128 (addressT);
+static void out_sleb128 (addressT);
static offsetT get_frag_fix (fragS *, segT);
static void out_set_addr (symbolS *);
static int size_inc_line_addr (int, addressT);
static void emit_inc_line_addr (int, addressT, char *, int);
static void out_inc_line_addr (int, addressT);
+static void out_fixed_inc_line_addr (int, symbolS *, symbolS *);
static void relax_inc_line_addr (int, symbolS *, symbolS *);
static void process_entries (segT, struct line_entry *);
static void out_file_list (void);
@@ -744,6 +753,14 @@ out_uleb128 (addressT value)
output_leb128 (frag_more (sizeof_leb128 (value, 0)), value, 0);
}
+/* Emit a signed "little-endian base 128" number. */
+
+static void
+out_sleb128 (addressT value)
+{
+ output_leb128 (frag_more (sizeof_leb128 (value, 1)), value, 1);
+}
+
/* Emit a tuple for .debug_abbrev. */
static inline void
@@ -977,6 +994,45 @@ out_inc_line_addr (int line_delta, addressT addr_delta)
emit_inc_line_addr (line_delta, addr_delta, frag_more (len), len);
}
+/* Write out an alternative form of line and address skips using
+ DW_LNS_fixed_advance_pc opcodes. This uses more space than the default
+ line and address information, but it helps support linker relaxation that
+ changes the code offsets. */
+
+static void
+out_fixed_inc_line_addr (int line_delta, symbolS *to_sym, symbolS *from_sym)
+{
+ expressionS expr;
+
+ /* INT_MAX is a signal that this is actually a DW_LNE_end_sequence. */
+ if (line_delta == INT_MAX)
+ {
+ out_opcode (DW_LNS_fixed_advance_pc);
+ expr.X_op = O_subtract;
+ expr.X_add_symbol = to_sym;
+ expr.X_op_symbol = from_sym;
+ expr.X_add_number = 0;
+ emit_expr (&expr, 2);
+
+ out_opcode (DW_LNS_extended_op);
+ out_byte (1);
+ out_opcode (DW_LNE_end_sequence);
+ return;
+ }
+
+ out_opcode (DW_LNS_advance_line);
+ out_sleb128 (line_delta);
+
+ out_opcode (DW_LNS_fixed_advance_pc);
+ expr.X_op = O_subtract;
+ expr.X_add_symbol = to_sym;
+ expr.X_op_symbol = from_sym;
+ expr.X_add_number = 0;
+ emit_expr (&expr, 2);
+
+ out_opcode (DW_LNS_copy);
+}
+
/* Generate a variant frag that we can use to relax address/line
increments between fragments of the target segment. */
@@ -1127,6 +1183,8 @@ process_entries (segT seg, struct line_entry *e)
out_set_addr (lab);
out_inc_line_addr (line_delta, 0);
}
+ else if (DWARF2_USE_FIXED_ADVANCE_PC)
+ out_fixed_inc_line_addr (line_delta, lab, last_lab);
else if (frag == last_frag)
out_inc_line_addr (line_delta, frag_ofs - last_frag_ofs);
else
@@ -1146,7 +1204,12 @@ process_entries (segT seg, struct line_entry *e)
/* Emit a DW_LNE_end_sequence for the end of the section. */
frag = last_frag_for_seg (seg);
frag_ofs = get_frag_fix (frag, seg);
- if (frag == last_frag)
+ if (DWARF2_USE_FIXED_ADVANCE_PC)
+ {
+ lab = symbol_temp_new (seg, frag_ofs, frag);
+ out_fixed_inc_line_addr (INT_MAX, lab, last_lab);
+ }
+ else if (frag == last_frag)
out_inc_line_addr (INT_MAX, frag_ofs - last_frag_ofs);
else
{