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dwarf2read.c: Make dir_index and file_name_index strong typedefs

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This should help catch mistakes related to mixing the 1-based DWARF
indexes with 0-based std::vector indexes, since the new types do not
implicitly convert to anything.

The change in read_formatted_entries relates to the fact that doing
the seemingly simpler:

 -	      uintp = &fe.dir_index;
 +	      uintp = (unsigned int *) &fe.dir_index;

would be undefined C/C++.  So to address that, I made the function
extract the form before assigning to the file_entry.  It felt natural
to use gdb::optional for "do I have this value", and this is what
motivated the previous patch that added the missing observer methods
to gdb::optional.

gdb/ChangeLog:
2017-04-04  Pedro Alves  <palves@redhat.com>

	* common/underlying.h: New file.
	* dwarf2read.c: Include "common/gdb_optional.h" and
	"common/underlying.h".
	(dir_index, file_name_index): New types.
	(file_entry): Use them.
	(file_entry::include): Use to_underlying.
	(line_header::add_file_name): Use dir_index.
	(read_formatted_entries): Use gdb::optional.  Read form before
	writting to file_entry.
	(dwarf_decode_line_header): Use dir_index.
	(lnp_state_machine::current_file): Use to_underlying.
	(lnp_state_machine::file): Change type to file_name_index.
	(dwarf_record_line): Use to_underlying.
	(init_lnp_state_machine): Use file_name_index.
	(dwarf_decode_lines_1): Use dir_index and file_name_index.
This commit is contained in:
Pedro Alves 2017-04-04 20:03:25 +01:00
parent d194f1fe51
commit ecfb656c37
3 changed files with 149 additions and 74 deletions
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18
gdb/ChangeLog
View File

@ -1,3 +1,21 @@
2017-04-04 Pedro Alves <palves@redhat.com>
* common/underlying.h: New file.
* dwarf2read.c: Include "common/gdb_optional.h" and
"common/underlying.h".
(dir_index, file_name_index): New types.
(file_entry): Use them.
(file_entry::include): Use to_underlying.
(line_header::add_file_name): Use dir_index.
(read_formatted_entries): Use gdb::optional. Read form before
writting to file_entry.
(dwarf_decode_line_header): Use dir_index.
(lnp_state_machine::current_file): Use to_underlying.
(lnp_state_machine::file): Change type to file_name_index.
(dwarf_record_line): Use to_underlying.
(init_lnp_state_machine): Use file_name_index.
(dwarf_decode_lines_1): Use dir_index and file_name_index.
2017-04-04 Pedro Alves <palves@redhat.com>
* common/gdb_optional.h (gdb::optiona): Add operator->, operator*,

32
gdb/common/underlying.h Normal file
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@ -0,0 +1,32 @@
/* Copyright (C) 2017 Free Software Foundation, Inc.
This file is part of GDB.
This program 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 3 of the License, or
(at your option) any later version.
This program 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 this program. If not, see <http://www.gnu.org/licenses/>. */
#ifndef COMMON_UNDERLYING_H
#define COMMON_UNDERLYING_H
#include <type_traits>
/* Convert an enum to its underlying value. */
template<typename E>
constexpr typename std::underlying_type<E>::type
to_underlying (E val) noexcept
{
return static_cast<typename std::underlying_type<E>::type> (val);
}
#endif

173
gdb/dwarf2read.c
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@ -71,6 +71,8 @@
#include "namespace.h"
#include "common/gdb_unlinker.h"
#include "common/function-view.h"
#include "common/gdb_optional.h"
#include "common/underlying.h"
#include <fcntl.h>
#include <sys/types.h>
@ -1052,20 +1054,28 @@ typedef void (die_reader_func_ftype) (const struct die_reader_specs *reader,
int has_children,
void *data);
/* A 1-based directory index. This is a strong typedef to prevent
accidentally using a directory index as a 0-based index into an
array/vector. */
enum class dir_index : unsigned int {};
/* Likewise, a 1-based file name index. */
enum class file_name_index : unsigned int {};
struct file_entry
{
file_entry () = default;
file_entry (const char *name_, unsigned int dir_index_,
file_entry (const char *name_, dir_index d_index_,
unsigned int mod_time_, unsigned int length_)
: name (name_),
dir_index (dir_index_),
d_index (d_index_),
mod_time (mod_time_),
length (length_)
{}
/* Return the include directory at DIR_INDEX stored in LH. Returns
NULL if DIR_INDEX is out of bounds. */
/* Return the include directory at D_INDEX stored in LH. Returns
NULL if D_INDEX is out of bounds. */
const char *include_dir (const line_header *lh) const;
/* The file name. Note this is an observing pointer. The memory is
@ -1073,7 +1083,7 @@ struct file_entry
const char *name {};
/* The directory index (1-based). */
unsigned int dir_index {};
dir_index d_index {};
unsigned int mod_time {};
@ -1099,25 +1109,33 @@ struct line_header
void add_include_dir (const char *include_dir);
/* Add an entry to the file name table. */
void add_file_name (const char *name, unsigned int dir_index,
void add_file_name (const char *name, dir_index d_index,
unsigned int mod_time, unsigned int length);
/* Return the include dir at INDEX (0-based). Returns NULL if INDEX
/* Return the include dir at INDEX (1-based). Returns NULL if INDEX
is out of bounds. */
const char *include_dir_at (unsigned int index) const
const char *include_dir_at (dir_index index) const
{
if (index >= include_dirs.size ())
/* Convert directory index number (1-based) to vector index
(0-based). */
size_t vec_index = to_underlying (index) - 1;
if (vec_index >= include_dirs.size ())
return NULL;
return include_dirs[index];
return include_dirs[vec_index];
}
/* Return the file name at INDEX (0-based). Returns NULL if INDEX
/* Return the file name at INDEX (1-based). Returns NULL if INDEX
is out of bounds. */
file_entry *file_name_at (unsigned int index)
file_entry *file_name_at (file_name_index index)
{
if (index >= file_names.size ())
/* Convert file name index number (1-based) to vector index
(0-based). */
size_t vec_index = to_underlying (index) - 1;
if (vec_index >= file_names.size ())
return NULL;
return &file_names[index];
return &file_names[vec_index];
}
/* Const version of the above. */
@ -1167,9 +1185,7 @@ typedef std::unique_ptr<line_header> line_header_up;
const char *
file_entry::include_dir (const line_header *lh) const
{
/* lh->include_dirs is 0-based, but the directory index numbers in
the statement program are 1-based. */
return lh->include_dir_at (dir_index - 1);
return lh->include_dir_at (d_index);
}
/* When we construct a partial symbol table entry we only
@ -17603,7 +17619,7 @@ line_header::add_include_dir (const char *include_dir)
void
line_header::add_file_name (const char *name,
unsigned int dir_index,
dir_index d_index,
unsigned int mod_time,
unsigned int length)
{
@ -17611,7 +17627,7 @@ line_header::add_file_name (const char *name,
fprintf_unfiltered (gdb_stdlog, "Adding file %u: %s\n",
(unsigned) file_names.size () + 1, name);
file_names.emplace_back (name, dir_index, mod_time, length);
file_names.emplace_back (name, d_index, mod_time, length);
}
/* A convenience function to find the proper .debug_line section for a CU. */
@ -17648,7 +17664,7 @@ read_formatted_entries (bfd *abfd, const gdb_byte **bufp,
const struct comp_unit_head *cu_header,
void (*callback) (struct line_header *lh,
const char *name,
unsigned int dir_index,
dir_index d_index,
unsigned int mod_time,
unsigned int length))
{
@ -17679,71 +17695,51 @@ read_formatted_entries (bfd *abfd, const gdb_byte **bufp,
for (formati = 0; formati < format_count; formati++)
{
ULONGEST content_type, form;
const char *string_trash;
const char **stringp = &string_trash;
unsigned int uint_trash, *uintp = &uint_trash;
content_type = read_unsigned_leb128 (abfd, format, &bytes_read);
ULONGEST content_type = read_unsigned_leb128 (abfd, format, &bytes_read);
format += bytes_read;
switch (content_type)
{
case DW_LNCT_path:
stringp = &fe.name;
break;
case DW_LNCT_directory_index:
uintp = &fe.dir_index;
break;
case DW_LNCT_timestamp:
uintp = &fe.mod_time;
break;
case DW_LNCT_size:
uintp = &fe.length;
break;
case DW_LNCT_MD5:
break;
default:
complaint (&symfile_complaints,
_("Unknown format content type %s"),
pulongest (content_type));
}
form = read_unsigned_leb128 (abfd, format, &bytes_read);
ULONGEST form = read_unsigned_leb128 (abfd, format, &bytes_read);
format += bytes_read;
gdb::optional<const char *> string;
gdb::optional<unsigned int> uint;
switch (form)
{
case DW_FORM_string:
*stringp = read_direct_string (abfd, buf, &bytes_read);
string.emplace (read_direct_string (abfd, buf, &bytes_read));
buf += bytes_read;
break;
case DW_FORM_line_strp:
*stringp = read_indirect_line_string (abfd, buf, cu_header, &bytes_read);
string.emplace (read_indirect_line_string (abfd, buf,
cu_header,
&bytes_read));
buf += bytes_read;
break;
case DW_FORM_data1:
*uintp = read_1_byte (abfd, buf);
uint.emplace (read_1_byte (abfd, buf));
buf += 1;
break;
case DW_FORM_data2:
*uintp = read_2_bytes (abfd, buf);
uint.emplace (read_2_bytes (abfd, buf));
buf += 2;
break;
case DW_FORM_data4:
*uintp = read_4_bytes (abfd, buf);
uint.emplace (read_4_bytes (abfd, buf));
buf += 4;
break;
case DW_FORM_data8:
*uintp = read_8_bytes (abfd, buf);
uint.emplace (read_8_bytes (abfd, buf));
buf += 8;
break;
case DW_FORM_udata:
*uintp = read_unsigned_leb128 (abfd, buf, &bytes_read);
uint.emplace (read_unsigned_leb128 (abfd, buf, &bytes_read));
buf += bytes_read;
break;
@ -17752,9 +17748,35 @@ read_formatted_entries (bfd *abfd, const gdb_byte **bufp,
current GDB. */
break;
}
switch (content_type)
{
case DW_LNCT_path:
if (string.has_value ())
fe.name = *string;
break;
case DW_LNCT_directory_index:
if (uint.has_value ())
fe.d_index = (dir_index) *uint;
break;
case DW_LNCT_timestamp:
if (uint.has_value ())
fe.mod_time = *uint;
break;
case DW_LNCT_size:
if (uint.has_value ())
fe.length = *uint;
break;
case DW_LNCT_MD5:
break;
default:
complaint (&symfile_complaints,
_("Unknown format content type %s"),
pulongest (content_type));
}
}
callback (lh, fe.name, fe.dir_index, fe.mod_time, fe.length);
callback (lh, fe.name, fe.d_index, fe.mod_time, fe.length);
}
*bufp = buf;
@ -17892,7 +17914,7 @@ dwarf_decode_line_header (unsigned int offset, struct dwarf2_cu *cu)
/* Read directory table. */
read_formatted_entries (abfd, &line_ptr, lh.get (), &cu->header,
[] (struct line_header *lh, const char *name,
unsigned int dir_index, unsigned int mod_time,
dir_index d_index, unsigned int mod_time,
unsigned int length)
{
lh->add_include_dir (name);
@ -17901,10 +17923,10 @@ dwarf_decode_line_header (unsigned int offset, struct dwarf2_cu *cu)
/* Read file name table. */
read_formatted_entries (abfd, &line_ptr, lh.get (), &cu->header,
[] (struct line_header *lh, const char *name,
unsigned int dir_index, unsigned int mod_time,
dir_index d_index, unsigned int mod_time,
unsigned int length)
{
lh->add_file_name (name, dir_index, mod_time, length);
lh->add_file_name (name, d_index, mod_time, length);
});
}
else
@ -17920,17 +17942,18 @@ dwarf_decode_line_header (unsigned int offset, struct dwarf2_cu *cu)
/* Read file name table. */
while ((cur_file = read_direct_string (abfd, line_ptr, &bytes_read)) != NULL)
{
unsigned int dir_index, mod_time, length;
unsigned int mod_time, length;
dir_index d_index;
line_ptr += bytes_read;
dir_index = read_unsigned_leb128 (abfd, line_ptr, &bytes_read);
d_index = (dir_index) read_unsigned_leb128 (abfd, line_ptr, &bytes_read);
line_ptr += bytes_read;
mod_time = read_unsigned_leb128 (abfd, line_ptr, &bytes_read);
line_ptr += bytes_read;
length = read_unsigned_leb128 (abfd, line_ptr, &bytes_read);
line_ptr += bytes_read;
lh->add_file_name (cur_file, dir_index, mod_time, length);
lh->add_file_name (cur_file, d_index, mod_time, length);
}
line_ptr += bytes_read;
}
@ -18036,7 +18059,7 @@ struct lnp_state_machine
{
/* lh->file_names is 0-based, but the file name numbers in the
statement program are 1-based. */
return the_line_header->file_name_at (file - 1);
return the_line_header->file_name_at (file);
}
/* The line number header. */
@ -18046,7 +18069,7 @@ struct lnp_state_machine
unsigned char op_index;
/* The line table index (1-based) of the current file. */
unsigned int file;
file_name_index file;
unsigned int line;
CORE_ADDR address;
int is_stmt;
@ -18206,7 +18229,7 @@ dwarf_record_line (lnp_reader_state *reader, lnp_state_machine *state,
fprintf_unfiltered (gdb_stdlog,
"Processing actual line %u: file %u,"
" address %s, is_stmt %u, discrim %u\n",
line, state->file,
line, to_underlying (state->file),
paddress (reader->gdbarch, state->address),
is_stmt, discriminator);
}
@ -18265,7 +18288,7 @@ init_lnp_state_machine (lnp_state_machine *state,
/* Initialize these according to the DWARF spec. */
state->op_index = 0;
state->file = 1;
state->file = (file_name_index) 1;
state->line = 1;
/* Call `gdbarch_adjust_dwarf2_line' on the initial 0 address as if there
was a line entry for it so that the backend has a chance to adjust it
@ -18423,12 +18446,13 @@ dwarf_decode_lines_1 (struct line_header *lh, struct dwarf2_cu *cu,
case DW_LNE_define_file:
{
const char *cur_file;
unsigned int dir_index, mod_time, length;
unsigned int mod_time, length;
dir_index dindex;
cur_file = read_direct_string (abfd, line_ptr,
&bytes_read);
line_ptr += bytes_read;
dir_index =
dindex = (dir_index)
read_unsigned_leb128 (abfd, line_ptr, &bytes_read);
line_ptr += bytes_read;
mod_time =
@ -18437,7 +18461,7 @@ dwarf_decode_lines_1 (struct line_header *lh, struct dwarf2_cu *cu,
length =
read_unsigned_leb128 (abfd, line_ptr, &bytes_read);
line_ptr += bytes_read;
lh->add_file_name (cur_file, dir_index, mod_time, length);
lh->add_file_name (cur_file, dindex, mod_time, length);
}
break;
case DW_LNE_set_discriminator:
@ -18501,8 +18525,9 @@ dwarf_decode_lines_1 (struct line_header *lh, struct dwarf2_cu *cu,
break;
case DW_LNS_set_file:
{
state_machine.file = read_unsigned_leb128 (abfd, line_ptr,
&bytes_read);
state_machine.file
= (file_name_index) read_unsigned_leb128 (abfd, line_ptr,
&bytes_read);
line_ptr += bytes_read;
const file_entry *fe = state_machine.current_file ();
@ -18866,11 +18891,11 @@ new_symbol_full (struct die_info *die, struct type *type, struct dwarf2_cu *cu,
cu);
if (attr)
{
unsigned int file_index = DW_UNSND (attr);
file_name_index file_index = (file_name_index) DW_UNSND (attr);
struct file_entry *fe;
if (cu->line_header != NULL && file_index > 0)
fe = cu->line_header->file_name_at (file_index - 1);
if (cu->line_header != NULL)
fe = cu->line_header->file_name_at (file_index);
else
fe = NULL;