return;
}
+/* Return non-zero if we should add LINE to the line number table.
+ LINE is the line to add, LAST_LINE is the last line that was added,
+ LAST_SUBFILE is the subfile for LAST_LINE.
+ LINE_HAS_NON_ZERO_DISCRIMINATOR is non-zero if LINE has ever
+ had a non-zero discriminator.
+
+ We have to be careful in the presence of discriminators.
+ E.g., for this line:
+
+ for (i = 0; i < 100000; i++);
+
+ clang can emit four line number entries for that one line,
+ each with a different discriminator.
+ See gdb.dwarf2/dw2-single-line-discriminators.exp for an example.
+
+ However, we want gdb to coalesce all four entries into one.
+ Otherwise the user could stepi into the middle of the line and
+ gdb would get confused about whether the pc really was in the
+ middle of the line.
+
+ Things are further complicated by the fact that two consecutive
+ line number entries for the same line is a heuristic used by gcc
+ to denote the end of the prologue. So we can't just discard duplicate
+ entries, we have to be selective about it. The heuristic we use is
+ that we only collapse consecutive entries for the same line if at least
+ one of those entries has a non-zero discriminator. PR 17276.
+
+ Note: Addresses in the line number state machine can never go backwards
+ within one sequence, thus this coalescing is ok. */
+
+static int
+dwarf_record_line_p (unsigned int line, unsigned int last_line,
+ int line_has_non_zero_discriminator,
+ struct subfile *last_subfile)
+{
+ if (current_subfile != last_subfile)
+ return 1;
+ if (line != last_line)
+ return 1;
+ /* Same line for the same file that we've seen already.
+ As a last check, for pr 17276, only record the line if the line
+ has never had a non-zero discriminator. */
+ if (!line_has_non_zero_discriminator)
+ return 1;
+ return 0;
+}
+
/* Use P_RECORD_LINE to record line number LINE beginning at address ADDRESS
in the line table of subfile SUBFILE. */
int is_stmt = lh->default_is_stmt;
int end_sequence = 0;
unsigned char op_index = 0;
+ unsigned int discriminator = 0;
+ /* The last line number that was recorded, used to coalesce
+ consecutive entries for the same line. This can happen, for
+ example, when discriminators are present. PR 17276. */
+ unsigned int last_line = 0;
+ int line_has_non_zero_discriminator = 0;
if (!decode_for_pst_p && lh->num_file_names >= file)
{
{
/* Special opcode. */
unsigned char adj_opcode;
+ int line_delta;
adj_opcode = op_code - lh->opcode_base;
address += (((op_index + (adj_opcode / lh->line_range))
* lh->minimum_instruction_length);
op_index = ((op_index + (adj_opcode / lh->line_range))
% lh->maximum_ops_per_instruction);
- line += lh->line_base + (adj_opcode % lh->line_range);
+ line_delta = lh->line_base + (adj_opcode % lh->line_range);
+ line += line_delta;
+ if (line_delta != 0)
+ line_has_non_zero_discriminator = discriminator != 0;
if (lh->num_file_names < file || file == 0)
dwarf2_debug_line_missing_file_complaint ();
/* For now we ignore lines not starting on an
{
dwarf_finish_line (gdbarch, last_subfile,
address, p_record_line);
- last_subfile = current_subfile;
}
- /* Append row to matrix using current values. */
- dwarf_record_line (gdbarch, current_subfile,
- line, address, p_record_line);
+ if (dwarf_record_line_p (line, last_line,
+ line_has_non_zero_discriminator,
+ last_subfile))
+ {
+ dwarf_record_line (gdbarch, current_subfile,
+ line, address, p_record_line);
+ }
+ last_subfile = current_subfile;
+ last_line = line;
}
}
+ discriminator = 0;
}
else switch (op_code)
{
break;
case DW_LNE_set_discriminator:
/* The discriminator is not interesting to the debugger;
- just ignore it. */
- line_ptr = extended_end;
+ just ignore it. We still need to check its value though:
+ if there are consecutive entries for the same
+ (non-prologue) line we want to coalesce them.
+ PR 17276. */
+ discriminator = read_unsigned_leb128 (abfd, line_ptr,
+ &bytes_read);
+ line_has_non_zero_discriminator |= discriminator != 0;
+ line_ptr += bytes_read;
break;
default:
complaint (&symfile_complaints,
{
dwarf_finish_line (gdbarch, last_subfile,
address, p_record_line);
- last_subfile = current_subfile;
}
- dwarf_record_line (gdbarch, current_subfile,
- line, address, p_record_line);
+ if (dwarf_record_line_p (line, last_line,
+ line_has_non_zero_discriminator,
+ last_subfile))
+ {
+ dwarf_record_line (gdbarch, current_subfile,
+ line, address, p_record_line);
+ }
+ last_subfile = current_subfile;
+ last_line = line;
}
}
+ discriminator = 0;
break;
case DW_LNS_advance_pc:
{
}
break;
case DW_LNS_advance_line:
- line += read_signed_leb128 (abfd, line_ptr, &bytes_read);
- line_ptr += bytes_read;
+ {
+ int line_delta
+ = read_signed_leb128 (abfd, line_ptr, &bytes_read);
+
+ line += line_delta;
+ if (line_delta != 0)
+ line_has_non_zero_discriminator = discriminator != 0;
+ line_ptr += bytes_read;
+ }
break;
case DW_LNS_set_file:
{
if (!decode_for_pst_p)
{
last_subfile = current_subfile;
+ line_has_non_zero_discriminator = discriminator != 0;
dwarf2_start_subfile (fe->name, dir, comp_dir);
}
}
projects / deliverable / binutils-gdb.git / blobdiff