--- /dev/null
+/* dwarf2dbg.c - DWARF2 debug support
+ Copyright (C) 1999 Hewlett-Packard Co
+ Contributed by David Mosberger-Tang <davidm@hpl.hp.com>
+
+ 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.
+
+ Logical line numbers can be controlled by the compiler via the
+ following two directives:
+
+ .file FILENO "file.c"
+ .loc FILENO LINENO [COLUMN]
+
+ FILENO is the filenumber. */
+
+#include "ansidecl.h"
+
+#include "as.h"
+#include "dwarf2dbg.h"
+#include "subsegs.h"
+
+#include <elf/dwarf2.h>
+
+#define BYTES_PER_ADDRESS (BFD_ARCH_SIZE / 8)
+
+/* Since we can't generate the prolog until the body is complete, we
+ use three different subsegments for .debug_line: one holding the
+ prolog, one for the directory and filename info, and one for the
+ body ("statement program"). */
+#define DL_PROLOG 0
+#define DL_FILES 1
+#define DL_BODY 2
+
+/* 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
+ dwarf2_finish(). */
+#define DWARF2_LINE_OPCODE_BASE 10
+
+#ifndef DWARF2_LINE_BASE
+ /* Minimum line offset in a special line info. opcode. This value
+ was chosen to give a reasonable range of values. */
+# define DWARF2_LINE_BASE -5
+#endif
+
+/* Range of line offsets in a special line info. opcode. */
+#ifndef DWARF2_LINE_RANGE
+# define DWARF2_LINE_RANGE 14
+#endif
+
+#ifndef DWARF2_LINE_MIN_INSN_LENGTH
+ /* Define the architecture-dependent minimum instruction length (in
+ bytes). This value should be rather too small than too big. */
+# define DWARF2_LINE_MIN_INSN_LENGTH 4
+#endif
+
+/* Flag that indicates the initial value of the is_stmt_start flag.
+ In the present implementation, we do not mark any lines as
+ the beginning of a source statement, because that information
+ is not made available by the GCC front-end. */
+#define DWARF2_LINE_DEFAULT_IS_STMT 1
+
+/* Flag that indicates the initial value of the is_stmt_start flag.
+ In the present implementation, we do not mark any lines as
+ the beginning of a source statement, because that information
+ is not made available by the GCC front-end. */
+#define DWARF2_LINE_DEFAULT_IS_STMT 1
+
+/* Given a special op, return the line skip amount: */
+#define SPECIAL_LINE(op) \
+ (((op) - DWARF2_LINE_OPCODE_BASE)%DWARF2_LINE_RANGE + DWARF2_LINE_BASE)
+
+/* Given a special op, return the address skip amount (in units of
+ DWARF2_LINE_MIN_INSN_LENGTH. */
+#define SPECIAL_ADDR(op) (((op) - DWARF2_LINE_OPCODE_BASE)/DWARF2_LINE_RANGE)
+
+/* The maximum address skip amont that can be encoded with a special op: */
+#define MAX_SPECIAL_ADDR_DELTA SPECIAL_ADDR(255)
+
+#define INITIAL_STATE \
+ /* initialize as per DWARF2.0 standard: */ \
+ 0, /* address */ \
+ 1, /* file */ \
+ 1, /* line */ \
+ 0, /* column */ \
+ DWARF2_LINE_DEFAULT_IS_STMT, /* is_stmt */ \
+ 0, /* basic_block */ \
+ 1 /* empty_sequence */
+
+static struct
+ {
+ /* state machine state as per DWARF2 manual: */
+ struct dwarf2_sm
+ {
+ bfd_vma addr;
+ unsigned int filenum;
+ unsigned int line;
+ unsigned int column;
+ unsigned int
+ is_stmt : 1,
+ basic_block : 1,
+ empty_sequence : 1; /* current code sequence has no DWARF2 directives? */
+ }
+ sm;
+
+ unsigned int
+ any_dwarf2_directives : 1; /* did we emit any DWARF2 line debug directives? */
+
+ segT text_seg; /* text segment "addr" is relative to */
+ subsegT text_subseg;
+ segT line_seg; /* ".debug_line" segment */
+ int last_filename; /* index of last filename that was used */
+ int num_filenames; /* index of last filename in use */
+ int filename_len; /* length of the filename array */
+ struct
+ {
+ int dir; /* valid after gen_dir_list() only */
+ char *name; /* full path before gen_dir_list(), filename afterwards */
+ }
+ *file;
+
+ struct dwarf2_line_info current; /* current source info: */
+
+ /* counters for statistical purposes: */
+ unsigned int num_line_entries;
+ unsigned int opcode_hist[256]; /* histogram of opcode frequencies */
+ }
+ls =
+ {
+ {
+ INITIAL_STATE
+ },
+ };
+
+#define out_byte(byte) FRAG_APPEND_1_CHAR(byte)
+#define out_opcode(opc) (out_byte ((opc)), ++ls.opcode_hist[(opc) & 0xff])
+
+/* Output an unsigned "little-endian base 128" number. */
+static void
+out_uleb128 (bfd_vma value)
+{
+ unsigned char byte, more = 0x80;
+
+ do
+ {
+ byte = value & 0x7f;
+ value >>= 7;
+ if (value == 0)
+ more = 0;
+ out_byte (more | byte);
+ }
+ while (more);
+}
+
+/* Output a signed "little-endian base 128" number. */
+static void
+out_sleb128 (bfd_signed_vma value)
+{
+ unsigned char byte, more = 0x80;
+
+ do
+ {
+ byte = value & 0x7f;
+ value >>= 7;
+ if (((value == 0) && ((byte & 0x40) == 0))
+ || ((value == -1) && ((byte & 0x40) != 0)))
+ more = 0;
+ out_byte (more | byte);
+ }
+ while (more);
+}
+
+/* Encode a pair of line and address skips as efficiently as possible.
+ Note that the line skip is signed, whereas the address skip is
+ unsigned. */
+static void
+gen_addr_line (int line_delta, bfd_vma addr_delta)
+{
+ unsigned int tmp, opcode;
+
+ tmp = line_delta - DWARF2_LINE_BASE;
+
+ if (tmp >= DWARF2_LINE_RANGE)
+ {
+ out_opcode (DW_LNS_advance_line);
+ out_sleb128 (line_delta);
+ tmp = 0 - DWARF2_LINE_BASE;
+ line_delta = 0;
+ }
+
+ tmp += DWARF2_LINE_OPCODE_BASE;
+
+ /* try using a special opcode: */
+ opcode = tmp + addr_delta*DWARF2_LINE_RANGE;
+ if (opcode <= 255)
+ {
+ out_opcode (opcode);
+ return;
+ }
+
+ /* try using DW_LNS_const_add_pc followed by special op: */
+ opcode = tmp + (addr_delta - MAX_SPECIAL_ADDR_DELTA)*DWARF2_LINE_RANGE;
+ if (opcode <= 255)
+ {
+ out_opcode (DW_LNS_const_add_pc);
+ out_opcode (opcode);
+ return;
+ }
+
+ out_opcode (DW_LNS_advance_pc);
+ out_uleb128 (addr_delta);
+
+ if (line_delta)
+ out_opcode (tmp); /* output line-delta */
+ else
+ out_opcode (DW_LNS_copy); /* append new row with current info */
+}
+
+static void
+reset_state_machine (void)
+{
+ static const struct dwarf2_sm initial_state = { INITIAL_STATE };
+
+ ls.sm = initial_state;
+}
+
+/* Set an absolute address (may results in a relocation entry): */
+static void
+out_set_addr (bfd_vma addr)
+{
+ subsegT saved_subseg;
+ segT saved_seg;
+ expressionS expr;
+ symbolS *sym;
+
+ saved_seg = now_seg;
+ saved_subseg = now_subseg;
+
+ subseg_set (ls.text_seg, ls.text_subseg);
+ sym = symbol_new (".L0\001", now_seg, addr, frag_now);
+
+ subseg_set (saved_seg, saved_subseg);
+
+ out_opcode (DW_LNS_extended_op);
+ out_uleb128 (BYTES_PER_ADDRESS + 1);
+
+ out_opcode (DW_LNE_set_address);
+ expr.X_op = O_symbol;
+ expr.X_add_symbol = sym;
+ expr.X_add_number = 0;
+ emit_expr (&expr, BYTES_PER_ADDRESS);
+}
+
+/* Emit DW_LNS_end_sequence and reset state machine. Does not
+ preserve the current segment/sub-segment! */
+static void
+out_end_sequence (void)
+{
+ bfd_vma addr, delta;
+
+ if (ls.text_seg)
+ {
+ subseg_set (ls.text_seg, ls.text_subseg);
+#ifdef md_current_text_addr
+ addr = md_current_text_addr ();
+#else
+ addr = frag_now_fix ();
+#endif
+ subseg_set (ls.line_seg, DL_BODY);
+ if (addr < ls.sm.addr)
+ {
+ out_set_addr (addr);
+ ls.sm.addr = addr;
+ }
+ else
+ {
+ delta = addr - ls.sm.addr;
+ if (delta > 0)
+ gen_addr_line (0, delta / DWARF2_LINE_MIN_INSN_LENGTH);
+ }
+ }
+ else
+ subseg_set (ls.line_seg, DL_BODY);
+
+ out_opcode (DW_LNS_extended_op);
+ out_uleb128 (1);
+ out_byte (DW_LNE_end_sequence);
+
+ reset_state_machine ();
+}
+
+/* Look up a filenumber either by filename or by filenumber. If both
+ a filenumber and a filename are specified, lookup by filename takes
+ precedence. If the filename cannot be found, it is added to the
+ filetable the filenumber for the new entry is returned. */
+static int
+get_filenum (int filenum, char *file)
+{
+ int i, last = filenum - 1;
+ char char0 = file[0];
+
+ if ((unsigned) last >= ls.num_filenames)
+ last = ls.last_filename;
+
+ /* do a quick check against the previously used filename: */
+ if (ls.num_filenames > 0 && ls.file[last].name[0] == char0
+ && strcmp (ls.file[last].name + 1, file + 1) == 0)
+ return last + 1;
+
+ /* no match, fall back to simple linear scan: */
+ for (i = 0; i < ls.num_filenames; ++i)
+ {
+ if (ls.file[i].name[0] == char0
+ && strcmp (ls.file[i].name + 1, file + 1) == 0)
+ {
+ ls.last_filename = i;
+ return i + 1;
+ }
+ }
+
+ /* no match: enter new filename */
+ if (ls.num_filenames >= ls.filename_len)
+ {
+ ls.filename_len += 13;
+ ls.file = xrealloc (ls.file, ls.filename_len * sizeof (ls.file[0]));
+ }
+ ls.file[ls.num_filenames].dir = 0;
+ ls.file[ls.num_filenames].name = file;
+ return ++ls.num_filenames;
+}
+
+void
+dwarf2_gen_line_info (bfd_vma addr, struct dwarf2_line_info *l)
+{
+ unsigned int filenum = l->filenum;
+ unsigned int any_output = 0;
+ subsegT saved_subseg;
+ segT saved_seg;
+ char *frag;
+
+ if (flag_debug)
+ fprintf (stderr, "line: addr %llx file `%s' line %u col %u flags %lx\n",
+ (long long) addr, l->filename, l->line, l->column, l->flags);
+
+ if (filenum > 0 && !l->filename)
+ {
+ if (filenum >= ls.num_filenames)
+ {
+ as_warn ("Encountered bad file number in line number debug info!");
+ return;
+ }
+ }
+ else if (l->filename)
+ filenum = get_filenum (filenum, l->filename);
+ else
+ return; /* no filename, no filnum => no play */
+
+ if (!ls.line_seg)
+ {
+ symbolS *secsym;
+
+ ls.line_seg = subseg_get (".debug_line", DL_BODY);
+ bfd_set_section_flags (stdoutput, ls.line_seg, SEC_READONLY);
+ secsym = symbol_find (".debug_line");
+ if (secsym)
+ secsym->bsym = ls.line_seg->symbol;
+ else
+ symbol_table_insert (section_symbol (ls.line_seg));
+ }
+
+ saved_seg = now_seg;
+ saved_subseg = now_subseg;
+ subseg_set (ls.line_seg, DL_BODY);
+
+ if (ls.text_seg != saved_seg || ls.text_subseg != saved_subseg)
+ {
+ if (!ls.sm.empty_sequence)
+ {
+ out_end_sequence (); /* terminate previous sequence */
+ ls.sm.empty_sequence = 1;
+ }
+ any_output = 1;
+ ls.text_seg = saved_seg;
+ ls.text_subseg = saved_subseg;
+ out_set_addr (addr);
+ ls.sm.addr = addr;
+ }
+
+ if (ls.sm.filenum != filenum)
+ {
+ any_output = 1;
+ out_opcode (DW_LNS_set_file);
+ out_uleb128 (filenum);
+ ls.sm.filenum = filenum;
+ }
+
+ if (ls.sm.column != l->column)
+ {
+ any_output = 1;
+ out_opcode (DW_LNS_set_column);
+ out_uleb128 (l->column);
+ ls.sm.column = l->column;
+ }
+
+ if (((l->flags & DWARF2_FLAG_BEGIN_STMT) != 0) != ls.sm.is_stmt)
+ {
+ any_output = 1;
+ out_opcode (DW_LNS_negate_stmt);
+ }
+
+ if (l->flags & DWARF2_FLAG_BEGIN_BLOCK)
+ {
+ any_output = 1;
+ out_opcode (DW_LNS_set_basic_block);
+ }
+
+ if (ls.sm.line != l->line)
+ {
+ any_output = 1;
+ if (addr < ls.sm.addr)
+ {
+ if (!ls.sm.empty_sequence)
+ {
+ out_end_sequence ();
+ ls.sm.empty_sequence = 1;
+ }
+ out_set_addr (addr);
+ ls.sm.addr = addr;
+ }
+ gen_addr_line (l->line - ls.sm.line,
+ (addr - ls.sm.addr) / DWARF2_LINE_MIN_INSN_LENGTH);
+ ls.sm.basic_block = 0;
+ ls.sm.line = l->line;
+ ls.sm.addr = addr;
+ }
+
+ subseg_set (saved_seg, saved_subseg);
+
+ ls.num_line_entries += any_output;
+ if (any_output)
+ ls.sm.empty_sequence = 0;
+}
+
+static void
+gen_dir_list (void)
+{
+ char *str, *slash, *dir_list, *dp, *cp;
+ int i, j, num_dirs;
+
+ dir_list = frag_more (0);
+ num_dirs = 0;
+
+ for (i = 0; i < ls.num_filenames; ++i)
+ {
+ str = ls.file[i].name;
+ slash = strrchr (str, '/');
+ if (slash)
+ {
+ *slash = '\0';
+ for (j = 0, dp = dir_list; j < num_dirs; ++j)
+ {
+ if (strcmp (str, dp) == 0)
+ {
+ ls.file[i].dir = j;
+ break;
+ }
+ dp += strlen (dp);
+ }
+ if (j >= num_dirs)
+ {
+ /* didn't find this directory: append it to the list */
+ size_t size = strlen (str) + 1;
+ cp = frag_more (size);
+ memcpy (cp, str, size);
+ ls.file[i].dir = ++num_dirs;
+ }
+ *slash = '/';
+ ls.file[i].name = slash + 1;
+ }
+ }
+ out_byte ('\0'); /* terminate directory list */
+}
+
+static void
+gen_file_list (void)
+{
+ size_t size;
+ char *cp;
+ int i;
+
+ for (i = 0; i < ls.num_filenames; ++i)
+ {
+ size = strlen (ls.file[i].name) + 1;
+ cp = frag_more (size);
+ memcpy (cp, ls.file[i].name, size);
+
+ out_uleb128 (ls.file[i].dir); /* directory number */
+ out_uleb128 (0); /* last modification timestamp */
+ out_uleb128 (0); /* filesize */
+ }
+ out_byte (0); /* terminate filename list */
+}
+
+void
+print_stats (unsigned long total_size)
+{
+ static const char *opc_name[] =
+ {
+ "extended", "copy", "advance_pc", "advance_line", "set_file",
+ "set_column", "negate_stmt", "set_basic_block", "const_add_pc",
+ "fixed_advance_pc"
+ };
+ int i, j;
+
+ fprintf (stderr, "Average size: %g bytes/line\n",
+ total_size / (double) ls.num_line_entries);
+
+ fprintf (stderr, "\nStandard opcode histogram:\n");
+
+ for (i = 0; i < sizeof (opc_name)/sizeof (opc_name[0]); ++i)
+ {
+ fprintf (stderr, "%s", opc_name[i]);
+ for (j = strlen (opc_name[i]); j < 16; ++j)
+ fprintf (stderr, " ");
+ fprintf (stderr, ": %u\n", ls.opcode_hist[i]);
+ }
+
+ fprintf (stderr, "\nSpecial opcodes:\naddr\t\t\t\tline skip\n");
+
+ fprintf (stderr, "skip: ");
+ for (j = DWARF2_LINE_BASE; j < DWARF2_LINE_BASE + DWARF2_LINE_RANGE; ++j)
+ fprintf (stderr, "%3d", j);
+ fprintf (stderr, "\n-----");
+
+ for (; i < 256; ++i)
+ {
+ j = SPECIAL_LINE (i);
+ if (j == DWARF2_LINE_BASE)
+ fprintf (stderr, "\n%4u: ",
+ DWARF2_LINE_MIN_INSN_LENGTH*SPECIAL_ADDR (i));
+ fprintf (stderr, " %2u", ls.opcode_hist[i]);
+ }
+ fprintf (stderr, "\n");
+}
+
+void
+dwarf2_finish (void)
+{
+ bfd_vma addr, body_size, total_size, prolog_size;
+ subsegT saved_subseg, line_prolog;
+ segT saved_seg;
+ char *cp;
+
+ if (!ls.line_seg)
+ /* no .debug_line segment, no work to do... */
+ return;
+
+ saved_seg = now_seg;
+ saved_subseg = now_subseg;
+
+ if (!ls.sm.empty_sequence)
+ out_end_sequence ();
+ total_size = body_size = frag_now_fix ();
+
+ /* now generate the directory and file lists: */
+ subseg_set (ls.line_seg, DL_FILES);
+ gen_dir_list ();
+ gen_file_list ();
+ total_size += frag_now_fix ();
+
+ /* and now the header ("statement program prolog", in DWARF2 lingo...) */
+ subseg_set (ls.line_seg, DL_PROLOG);
+
+ cp = frag_more (15 + DWARF2_LINE_OPCODE_BASE - 1);
+
+ total_size += frag_now_fix ();
+ prolog_size = total_size - body_size - 10;
+
+# define STUFF(val,size) md_number_to_chars (cp, val, size); cp += size;
+ STUFF (total_size - 4, 4); /* length */
+ STUFF (2, 2); /* version */
+ STUFF (prolog_size, 4); /* prologue_length */
+ STUFF (DWARF2_LINE_MIN_INSN_LENGTH, 1);
+ STUFF (DWARF2_LINE_DEFAULT_IS_STMT, 1);
+ STUFF (DWARF2_LINE_BASE, 1);
+ STUFF (DWARF2_LINE_RANGE, 1);
+ STUFF (DWARF2_LINE_OPCODE_BASE, 1);
+
+ /* standard_opcode_lengths: */
+ STUFF (0, 1); /* DW_LNS_copy */
+ STUFF (1, 1); /* DW_LNS_advance_pc */
+ STUFF (1, 1); /* DW_LNS_advance_line */
+ STUFF (1, 1); /* DW_LNS_set_file */
+ STUFF (1, 1); /* DW_LNS_set_column */
+ STUFF (0, 1); /* DW_LNS_negate_stmt */
+ STUFF (0, 1); /* DW_LNS_set_basic_block */
+ STUFF (0, 1); /* DW_LNS_const_add_pc */
+ STUFF (1, 1); /* DW_LNS_fixed_advance_pc */
+
+ subseg_set (saved_seg, saved_subseg);
+
+ if (flag_debug)
+ print_stats (total_size);
+}
+
+void
+dwarf2_directive_file (int dummy)
+{
+ int len;
+
+ ls.any_dwarf2_directives = 1;
+
+ if (debug_type == DEBUG_NONE)
+ /* Automatically turn on DWARF2 debug info unless something else
+ has been selected. */
+ debug_type = DEBUG_DWARF2;
+
+ ls.current.filenum = get_absolute_expression ();
+ ls.current.filename = demand_copy_C_string (&len);
+
+ demand_empty_rest_of_line ();
+}
+
+void
+dwarf2_directive_loc (int dummy)
+{
+ ls.any_dwarf2_directives = 1;
+
+ ls.current.filenum = get_absolute_expression ();
+ SKIP_WHITESPACE ();
+ ls.current.line = get_absolute_expression ();
+ SKIP_WHITESPACE ();
+ ls.current.column = get_absolute_expression ();
+ demand_empty_rest_of_line ();
+
+ ls.current.flags = DWARF2_FLAG_BEGIN_STMT;
+
+#ifndef NO_LISTING
+ if (listing)
+ listing_source_line (ls.current.line);
+#endif
+}
+
+void
+dwarf2_where (struct dwarf2_line_info *line)
+{
+ if (ls.any_dwarf2_directives)
+ *line = ls.current;
+ else
+ {
+ char *filename;
+
+ as_where (&line->filename, &line->line);
+ line->filenum = 0;
+ line->column = 0;
+ line->flags = DWARF2_FLAG_BEGIN_STMT;
+ }
+}
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