[RFA 01/13] Replace really_free_pendings with a scoped_ class

Tom Tromey
2017-11-02T22:36:24Z

This introduces scoped_free_pendings, and changes users of
really_free_pendings to use it instead, removing some clenaups.

I tried to examine the affected code to ensure there aren't dangling
cleanups in the vicinity.

gdb/ChangeLog
2017-11-02 Tom Tromey <tom@tromey.com>

* dwarf2read.c (process_full_comp_unit, process_full_type_unit):
Use scoped_free_pendings.
* dbxread.c (dbx_symfile_read, dbx_psymtab_to_symtab_1): Use
scoped_free_pendings.
* xcoffread.c (xcoff_psymtab_to_symtab_1): Use scoped_free_pendings.
(xcoff_initial_scan): Likewise.
* buildsym.c (reset_symtab_globals): Update comment.
(scoped_free_pendings): Rename from really_free_pendings.
(prepare_for_building): Update comment.
(buildsym_init): Likewise.
* buildsym.h (class scoped_free_pendings): New class.
(really_free_pendings): Don't declare.
---
gdb/ChangeLog | 15 +++++++++++++++
gdb/buildsym.c | 26 ++++++++++----------------
gdb/buildsym.h | 10 +++++++++-
gdb/dbxread.c | 10 ++--------
gdb/dwarf2read.c | 12 ++++--------
gdb/xcoffread.c | 10 ++--------
6 files changed, 42 insertions(+), 41 deletions(-)

diff --git a/gdb/buildsym.c b/gdb/buildsym.c
index 07bfbd5038..d07bfb3d13 100644
--- a/gdb/buildsym.c
+++ b/gdb/buildsym.c
@@ -26,11 +26,10 @@
The basic way this module is used is as follows:

buildsym_init ();
- cleanups = make_cleanup (really_free_pendings, NULL);
+ scoped_free_pendings free_pending;
cust = start_symtab (...);
... read debug info ...
cust = end_symtab (...);
- do_cleanups (cleanups);

The compunit symtab pointer ("cust") is returned from both start_symtab
and end_symtab to simplify the debug info readers.
@@ -42,31 +41,28 @@
Reading DWARF Type Units is another variation:

buildsym_init ();
- cleanups = make_cleanup (really_free_pendings, NULL);
+ scoped_free_pendings free_pending;
cust = start_symtab (...);
... read debug info ...
cust = end_expandable_symtab (...);
- do_cleanups (cleanups);

And then reading subsequent Type Units within the containing "Comp Unit"
will use a second flow:

buildsym_init ();
- cleanups = make_cleanup (really_free_pendings, NULL);
+ scoped_free_pendings free_pending;
cust = restart_symtab (...);
... read debug info ...
cust = augment_type_symtab (...);
- do_cleanups (cleanups);

dbxread.c and xcoffread.c use another variation:

buildsym_init ();
- cleanups = make_cleanup (really_free_pendings, NULL);
+ scoped_free_pendings free_pending;
cust = start_symtab (...);
... read debug info ...
cust = end_symtab (...);
... start_symtab + read + end_symtab repeated ...
- do_cleanups (cleanups);
*/

#include "defs.h"
@@ -269,15 +265,13 @@ find_symbol_in_list (struct pending *list, char *name, int length)
return (NULL);
}

-/* At end of reading syms, or in case of quit, ensure everything associated
- with building symtabs is freed. This is intended to be registered as a
- cleanup before doing psymtab->symtab expansion.
+/* At end of reading syms, or in case of quit, ensure everything
+ associated with building symtabs is freed.

N.B. This is *not* intended to be used when building psymtabs. Some debug
info readers call this anyway, which is harmless if confusing. */

-void
-really_free_pendings (void *dummy)
+scoped_free_pendings::~scoped_free_pendings ()
{
struct pending *next, *next1;

@@ -1028,7 +1022,7 @@ prepare_for_building (const char *name, CORE_ADDR start_addr)
context_stack_depth = 0;

/* These should have been reset either by successful completion of building
- a symtab, or by the really_free_pendings cleanup. */
+ a symtab, or by the scoped_free_pendings destructor. */
gdb_assert (file_symbols == NULL);
gdb_assert (global_symbols == NULL);
gdb_assert (global_using_directives == NULL);
@@ -1169,7 +1163,7 @@ watch_main_source_file_lossage (void)
/* Reset state after a successful building of a symtab.
This exists because dbxread.c and xcoffread.c can call
start_symtab+end_symtab multiple times after one call to buildsym_init,
- and before the really_free_pendings cleanup is called.
+ and before the scoped_free_pendings destructor is called.
We keep the free_pendings list around for dbx/xcoff sake. */

static void
@@ -1753,7 +1747,7 @@ buildsym_init (void)
context_stack = XNEWVEC (struct context_stack, context_stack_size);
}

- /* Ensure the really_free_pendings cleanup was called after
+ /* Ensure the scoped_free_pendings destructor was called after
the last time. */
gdb_assert (free_pendings == NULL);
gdb_assert (pending_blocks == NULL);
diff --git a/gdb/buildsym.h b/gdb/buildsym.h
index 60109a0da2..accb1f0347 100644
--- a/gdb/buildsym.h
+++ b/gdb/buildsym.h
@@ -212,7 +212,15 @@ extern struct block *finish_block (struct symbol *symbol,
extern void record_block_range (struct block *,
CORE_ADDR start, CORE_ADDR end_inclusive);

-extern void really_free_pendings (void *dummy);
+class scoped_free_pendings
+{
+public:
+
+ scoped_free_pendings () = default;
+ ~scoped_free_pendings ();
+
+ DISABLE_COPY_AND_ASSIGN (scoped_free_pendings);
+};

extern void start_subfile (const char *name);

diff --git a/gdb/dbxread.c b/gdb/dbxread.c
index ce00962809..1618a56136 100644
--- a/gdb/dbxread.c
+++ b/gdb/dbxread.c
@@ -516,7 +516,6 @@ dbx_symfile_read (struct objfile *objfile, symfile_add_flags symfile_flags)
{
bfd *sym_bfd;
int val;
- struct cleanup *back_to;

sym_bfd = objfile->obfd;

@@ -539,7 +538,7 @@ dbx_symfile_read (struct objfile *objfile, symfile_add_flags symfile_flags)
symbol_table_offset = DBX_SYMTAB_OFFSET (objfile);

free_pending_blocks ();
- back_to = make_cleanup (really_free_pendings, 0);
+ scoped_free_pendings free_pending;

minimal_symbol_reader reader (objfile);

@@ -551,8 +550,6 @@ dbx_symfile_read (struct objfile *objfile, symfile_add_flags symfile_flags)
minimal symbols for this objfile. */

reader.install ();
-
- do_cleanups (back_to);
}

/* Initialize anything that needs initializing when a completely new
@@ -2186,7 +2183,6 @@ dbx_end_psymtab (struct objfile *objfile, struct partial_symtab *pst,
static void
dbx_psymtab_to_symtab_1 (struct objfile *objfile, struct partial_symtab *pst)
{
- struct cleanup *old_chain;
int i;

if (pst->readin)
@@ -2220,15 +2216,13 @@ dbx_psymtab_to_symtab_1 (struct objfile *objfile, struct partial_symtab *pst)
/* Init stuff necessary for reading in symbols */
stabsread_init ();
buildsym_init ();
- old_chain = make_cleanup (really_free_pendings, 0);
+ scoped_free_pendings free_pending;
file_string_table_offset = FILE_STRING_OFFSET (pst);
symbol_size = SYMBOL_SIZE (pst);

/* Read in this file's symbols. */
bfd_seek (objfile->obfd, SYMBOL_OFFSET (pst), SEEK_SET);
read_ofile_symtab (objfile, pst);
-
- do_cleanups (old_chain);
}

pst->readin = 1;
diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
index 686fa3f3d3..433a9272b8 100644
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -8317,7 +8317,7 @@ process_full_comp_unit (struct dwarf2_per_cu_data *per_cu,
struct gdbarch *gdbarch = get_objfile_arch (objfile);
CORE_ADDR lowpc, highpc;
struct compunit_symtab *cust;
- struct cleanup *back_to, *delayed_list_cleanup;
+ struct cleanup *delayed_list_cleanup;
CORE_ADDR baseaddr;
struct block *static_block;
CORE_ADDR addr;
@@ -8325,7 +8325,7 @@ process_full_comp_unit (struct dwarf2_per_cu_data *per_cu,
baseaddr = ANOFFSET (objfile->section_offsets, SECT_OFF_TEXT (objfile));

buildsym_init ();
- back_to = make_cleanup (really_free_pendings, NULL);
+ scoped_free_pendings free_pending;
delayed_list_cleanup = make_cleanup (free_delayed_list, cu);

cu->list_in_scope = &file_symbols;
@@ -8407,8 +8407,6 @@ process_full_comp_unit (struct dwarf2_per_cu_data *per_cu,

/* Push it for inclusion processing later. */
VEC_safe_push (dwarf2_per_cu_ptr, dwarf2_per_objfile->just_read_cus, per_cu);
-
- do_cleanups (back_to);
}

/* Generate full symbol information for type unit PER_CU, whose DIEs have
@@ -8421,14 +8419,14 @@ process_full_type_unit (struct dwarf2_per_cu_data *per_cu,
struct dwarf2_cu *cu = per_cu->cu;
struct objfile *objfile = per_cu->objfile;
struct compunit_symtab *cust;
- struct cleanup *back_to, *delayed_list_cleanup;
+ struct cleanup *delayed_list_cleanup;
struct signatured_type *sig_type;

gdb_assert (per_cu->is_debug_types);
sig_type = (struct signatured_type *) per_cu;

buildsym_init ();
- back_to = make_cleanup (really_free_pendings, NULL);
+ scoped_free_pendings free_pending;
delayed_list_cleanup = make_cleanup (free_delayed_list, cu);

cu->list_in_scope = &file_symbols;
@@ -8483,8 +8481,6 @@ process_full_type_unit (struct dwarf2_per_cu_data *per_cu,
pst->compunit_symtab = cust;
pst->readin = 1;
}
-
- do_cleanups (back_to);
}

/* Process an imported unit DIE. */
diff --git a/gdb/xcoffread.c b/gdb/xcoffread.c
index ea11b3f966..2e4f30f291 100644
--- a/gdb/xcoffread.c
+++ b/gdb/xcoffread.c
@@ -1833,7 +1833,6 @@ find_linenos (struct bfd *abfd, struct bfd_section *asect, void *vpinfo)
static void
xcoff_psymtab_to_symtab_1 (struct objfile *objfile, struct partial_symtab *pst)
{
- struct cleanup *old_chain;
int i;

if (!pst)
@@ -1870,11 +1869,9 @@ xcoff_psymtab_to_symtab_1 (struct objfile *objfile, struct partial_symtab *pst)
/* Init stuff necessary for reading in symbols. */
stabsread_init ();
buildsym_init ();
- old_chain = make_cleanup (really_free_pendings, 0);

+ scoped_free_pendings free_pending;
read_xcoff_symtab (objfile, pst);
-
- do_cleanups (old_chain);
}

pst->readin = 1;
@@ -2950,7 +2947,6 @@ xcoff_initial_scan (struct objfile *objfile, symfile_add_flags symfile_flags)
{
bfd *abfd;
int val;
- struct cleanup *back_to;
int num_symbols; /* # of symbols */
file_ptr symtab_offset; /* symbol table and */
file_ptr stringtab_offset; /* string table file offsets */
@@ -3027,8 +3023,8 @@ xcoff_initial_scan (struct objfile *objfile, symfile_add_flags symfile_flags)
init_psymbol_list (objfile, num_symbols);

free_pending_blocks ();
- back_to = make_cleanup (really_free_pendings, 0);

+ scoped_free_pendings free_pending;
minimal_symbol_reader reader (objfile);

/* Now that the symbol table data of the executable file are all in core,
@@ -3047,8 +3043,6 @@ xcoff_initial_scan (struct objfile *objfile, symfile_add_flags symfile_flags)
dwarf2_build_psymtabs (objfile);

dwarf2_build_frame_info (objfile);
-
- do_cleanups (back_to);
}
\f
static void
--
2.13.6