From: Pedro Alves <palves@redhat.com>
To: gdb-patches@sourceware.org
Subject: [PATCH 3/5] dwarf2read.c: Make dir_index and file_name_index strong typedefs
Date: Wed, 29 Mar 2017 02:25:00 -0000 [thread overview]
Message-ID: <1490754298-9455-4-git-send-email-palves@redhat.com> (raw)
In-Reply-To: <1490754298-9455-1-git-send-email-palves@redhat.com>
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:
yyyy-mm-dd 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.
---
gdb/common/underlying.h | 32 +++++++++++
gdb/dwarf2read.c | 141 +++++++++++++++++++++++++++---------------------
2 files changed, 112 insertions(+), 61 deletions(-)
create mode 100644 gdb/common/underlying.h
diff --git a/gdb/common/underlying.h b/gdb/common/underlying.h
new file mode 100644
index 0000000..41ff117
--- /dev/null
+++ b/gdb/common/underlying.h
@@ -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
diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
index e54e818..fddec86 100644
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -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 {};
@@ -1099,7 +1109,7 @@ 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
@@ -1169,7 +1179,7 @@ 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 (to_underlying (d_index) - 1);
}
/* When we construct a partial symbol table entry we only
@@ -17603,7 +17613,7 @@ 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 +17621,7 @@ 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 +17658,7 @@ 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 +17689,51 @@ 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 +17742,35 @@ 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 +17908,7 @@ 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 +17917,10 @@ 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 +17936,18 @@ 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 +18053,7 @@ 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 (to_underlying (file) - 1);
}
/* The line number header. */
@@ -18046,7 +18063,7 @@ 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 +18223,7 @@ 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 +18282,7 @@ 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 +18440,13 @@ 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 +18455,7 @@ 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 +18519,9 @@ 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 ();
--
2.5.5
next prev parent reply other threads:[~2017-03-29 2:25 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-29 2:25 [PATCH 0/5] dwarf2read.c: Some C++fycation Pedro Alves
2017-03-29 2:25 ` Pedro Alves [this message]
2017-03-29 15:36 ` [PATCH 3/5] dwarf2read.c: Make dir_index and file_name_index strong typedefs Simon Marchi
2017-04-04 18:54 ` Pedro Alves
2017-04-04 19:06 ` Pedro Alves
2017-03-29 2:25 ` [PATCH 5/5] dwarf2read.c: C++fy lnp_state_machine Pedro Alves
2017-03-29 2:25 ` [PATCH 2/5] gdb::optional: Add observers Pedro Alves
2017-03-29 2:25 ` [PATCH 1/5] dwarf2read.c: Some C++fycation, use std::vector, std::unique_ptr Pedro Alves
2017-03-29 15:06 ` Simon Marchi
2017-04-04 18:57 ` Pedro Alves
2017-03-29 2:32 ` [PATCH 4/5] Make sect_offset and cu_offset strong typedefs instead of structs Pedro Alves
2017-03-29 15:46 ` Simon Marchi
2017-04-05 15:13 ` Pedro Alves
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