binutils-gdb/gdb/cp-support.h
Pedro Alves a20714ff39 Make "break foo" find "A::foo", A::B::foo", etc. [C++ and wild matching]
This patch teaches GDB about setting breakpoints in all scopes
(namespaces and classes) by default.

Here's a contrived example:

  (gdb) b func<tab>
  (anonymous namespace)::A::function()            Bn::(anonymous namespace)::B::function()        function(int, int)
  (anonymous namespace)::B::function()            Bn::(anonymous namespace)::function()           gdb::(anonymous namespace)::A::function()
  (anonymous namespace)::B::function() const      Bn::(anonymous namespace)::function(int, int)   gdb::(anonymous namespace)::function()
  (anonymous namespace)::function()               Bn::B::func()                                   gdb::(anonymous namespace)::function(int, int)
  (anonymous namespace)::function(int, int)       Bn::B::function()                               gdb::A::func()
  A::func()                                       Bn::func()                                      gdb::A::function()
  A::function()                                   Bn::function()                                  gdb::func()
  B::func()                                       Bn::function(int, int)                          gdb::function()
  B::function()                                   Bn::function(long)                              gdb::function(int, int)
  B::function() const                             func()                                          gdb::function(long)
  B::function_const() const                       function()
  (gdb) b function
  Breakpoint 1 at 0x4005ce: function. (26 locations)

  (gdb) b B::function<tab>
  (anonymous namespace)::B::function()        B::function() const                         Bn::B::function()
  (anonymous namespace)::B::function() const  B::function_const() const
  B::function()                               Bn::(anonymous namespace)::B::function()
  (gdb) b B::function
  Breakpoint 1 at 0x40072c: B::function. (6 locations)

To get back the original behavior of interpreting the function name as
a fully-qualified name, you can use the new "-qualified" (or "-q")
option/flag (added by this commit).  For example:

 (gdb) b B::function
 (anonymous namespace)::B::function()        B::function() const                         Bn::B::function()
 (anonymous namespace)::B::function() const  B::function_const() const
 B::function()                               Bn::(anonymous namespace)::B::function()

vs:

 (gdb) b -qualified B::function
 B::function()              B::function() const        B::function_const() const

I've chosen "-qualified" / "-q" because "-f" (for "full" or
"fully-qualified") is already taken for "-function".

Note: the "-qualified" option works with both linespecs and explicit
locations.  I.e., these are equivalent:

 (gdb) b -q func
 (gdb) b -q -f func

and so are these:

 (gdb) b -q filename.cc:func
 (gdb) b -q -s filename.cc -f func
 (gdb) b -s filename.cc -q -f func
 (gdb) b -s filename.cc -f func -q

To better understand why I consider wild matching the better default,
consider what happens when we get to the point when _all_ of GDB is
wrapped under "namespace gdb {}".  I have a patch series that does
that, and when I started debugging that GDB, I immediately became
frustrated.  You'd have to write "b gdb::internal_error", "b
gdb::foo", "b gdb::bar", etc. etc., which gets annoying pretty
quickly.  OTOH, consider how this makes it very easy to set
breakpoints in classes wrapped in anonymous namespaces.  You just
don't think of them, GDB finds the symbols for you automatically.

(At the Cauldron a couple months ago, several people told me that they
run into a similar issue when debugging other C++ projects.  One
example was when debugging LLVM, which puts all its code under the
"llvm" namespace.)

Implementation-wise, what the patch does is:

  - makes C++ symbol name hashing only consider the last component of
    a symbol name. (so that we can look up symbol names by
    last-component name only).

  - adds a C++ symbol name matcher for symbol_name_match_type::WILD,
    which ignores missing leading specifiers / components.

  - adjusts a few preexisting testsuite tests to use "-qualified" when
    they mean it.

  - adds new testsuite tests.

  - adds unit tests.

Grows the gdb.linespec/ tests like this:

  -# of expected passes           7823
  +# of expected passes           8977

gdb/ChangeLog:
2017-11-29  Pedro Alves  <palves@redhat.com>

	* NEWS: Mention that breakpoints on C++ functions are now set on
	on all namespaces/classes by default, and mention "break
	-qualified".
	* ax-gdb.c (agent_command_1): Adjust to pass a
	symbol_name_match_type to new_linespec_location.
	* breakpoint.c (parse_breakpoint_sals): Adjust to
	get_linespec_location's return type change.
	(strace_marker_create_sals_from_location): Adjust to pass a
	symbol_name_match_type to new_linespec_location.
	(strace_marker_decode_location): Adjust to get_linespec_location's
	return type change.
	(strace_command): Adjust to pass a symbol_name_match_type to
	new_linespec_location.
	(LOCATION_HELP_STRING): Add paragraph about wildmatching, and
	mention "-qualified".
	* c-lang.c (cplus_language_defn): Install cp_search_name_hash.
	* completer.c (explicit_location_match_type::MATCH_QUALIFIED): New
	enumerator.
	(complete_address_and_linespec_locations): New parameter
	'match_type'.  Pass it down.
	(explicit_options): Add "-qualified".
	(collect_explicit_location_matches): Pass the requested match type
	to the linespec completers.  Handle MATCH_QUALIFIED.
	(location_completer): Handle "-qualified" combined with linespecs.
	* cp-support.c (cp_search_name_hash): New.
	(cp_symbol_name_matches_1): Implement wild matching for C++.
	(cp_fq_symbol_name_matches): Reimplement.
	(cp_get_symbol_name_matcher): Return different matchers depending
	on the lookup name's match type.
	(selftests::test_cp_symbol_name_matches): Add wild matching tests.
	* cp-support.h (cp_search_name_hash): New declaration.
	* dwarf2read.c
	(selftests::dw2_expand_symtabs_matching::test_symbols): Add
	symbols.
	(test_dw2_expand_symtabs_matching_symbol): Add wild matching
	tests.
	* guile/scm-breakpoint.c (gdbscm_register_breakpoint_x): Adjust to
	pass a symbol_name_match_type to new_linespec_location.
	* linespec.c (linespec_parse_basic): Lookup function symbols using
	the parser's symbol name match type.
	(convert_explicit_location_to_linespec): New
	symbol_name_match_type parameter.  Pass it down to
	find_linespec_symbols.
	(convert_explicit_location_to_sals): Pass the location's name
	match type to convert_explicit_location_to_linespec.
	(parse_linespec): New match_type parameter.  Save it in the
	parser.
	(linespec_parser_new): Default to symbol_name_match_type::WILD.
	(linespec_complete_function): New symbol_name_match_type
	parameter.  Use it.
	(complete_linespec_component): Pass down the parser's recorded
	name match type.
	(linespec_complete_label): New symbol_name_match_type parameter.
	Use it.
	(linespec_complete): New symbol_name_match_type parameter.  Save
	it in the parser and pass it down.  Adjust to
	get_linespec_location's prototype change.
	(find_function_symbols, find_linespec_symbols): New
	symbol_name_match_type parameter.  Pass it down instead of
	assuming symbol_name_match_type::WILD.
	* linespec.h (linespec_complete, linespec_complete_function)
	(linespec_complete_label): New symbol_name_match_type parameter.
	* location.c (event_location::linespec_location): Now a struct
	linespec_location.
	(EL_LINESPEC): Adjust.
	(initialize_explicit_location): Default to
	symbol_name_match_type::WILD.
	(new_linespec_location): New symbol_name_match_type parameter.
	Record it in the location.
	(get_linespec_location): Now returns a struct linespec_location.
	(new_explicit_location): Also copy func_name_match_type.
	(explicit_to_string_internal)
	(string_to_explicit_location): Handle "-qualified".
	(copy_event_location): Adjust to LINESPEC_LOCATION type change.
	Copy symbol_name_match_type fields.
	(event_location_deleter::operator()): Adjust to LINESPEC_LOCATION
	type change.
	(event_location_to_string): Adjust to LINESPEC_LOCATION type
	change.  Handle "-qualfied".
	(string_to_explicit_location): Handle "-qualified".
	(string_to_event_location_basic): New symbol_name_match_type
	parameter.  Pass it down.
	(string_to_event_location): Handle "-qualified".
	* location.h (struct linespec_location): New.
	(explicit_location::func_name_match_type): New field.
	(new_linespec_location): Now returns a const linespec_location *.
	(string_to_event_location_basic): New symbol_name_match_type
	parameter.
	(explicit_completion_info::saw_explicit_location_option): New
	field.
	* mi/mi-cmd-break.c (mi_cmd_break_insert_1): Adjust to pass a
	symbol_name_match_type to new_linespec_location.
	* python/py-breakpoint.c (bppy_init): Likewise.
	* python/python.c (gdbpy_decode_line): Likewise.

gdb/testsuite/ChangeLog:
2017-11-29  Pedro Alves  <palves@redhat.com>

	* gdb.base/langs.exp: Use -qualified.
	* gdb.cp/meth-typedefs.exp: Use -qualified, and add tests without
	it.
	* gdb.cp/namespace.exp: Use -qualified.
	* gdb.linespec/cpcompletion.exp (overload-2, fqn, fqn-2)
	(overload-3, template-overload, template-ret-type, const-overload)
	(const-overload-quoted, anon-ns, ambiguous-prefix): New
	procedures.
	(test_driver): Call them.
	* gdb.cp/save-bp-qualified.cc: New.
	* gdb.cp/save-bp-qualified.exp: New.
	* gdb.linespec/explicit.exp: Test -qualified.
	* lib/completion-support.exp (completion::explicit_opts_list): Add
	"-qualified".
	* lib/gdb.exp (gdb_breakpoint): Handle "qualified".

gdb/doc/ChangeLog:
2017-11-29  Pedro Alves  <palves@redhat.com>

	* gdb.texinfo (Linespec Locations): Document how "function" is
	interpreted in C++ and Ada.  Document "-qualified".
	(Explicit Locations): Document how "-function" is interpreted in
	C++ and Ada.  Document "-qualified".
2017-11-29 19:43:48 +00:00

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C++

/* Helper routines for C++ support in GDB.
Copyright (C) 2002-2017 Free Software Foundation, Inc.
Contributed by MontaVista Software.
Namespace support contributed by David Carlton.
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 CP_SUPPORT_H
#define CP_SUPPORT_H
/* We need this for 'domain_enum', alas... */
#include "symtab.h"
#include "vec.h"
#include "gdb_vecs.h"
#include "gdb_obstack.h"
/* Opaque declarations. */
struct symbol;
struct block;
struct objfile;
struct type;
struct demangle_component;
struct using_direct;
/* A string representing the name of the anonymous namespace used in GDB. */
#define CP_ANONYMOUS_NAMESPACE_STR "(anonymous namespace)"
/* The length of the string representing the anonymous namespace. */
#define CP_ANONYMOUS_NAMESPACE_LEN 21
/* A string representing the start of an operator name. */
#define CP_OPERATOR_STR "operator"
/* The length of CP_OPERATOR_STR. */
#define CP_OPERATOR_LEN 8
/* The result of parsing a name. */
struct demangle_parse_info
{
demangle_parse_info ();
~demangle_parse_info ();
/* The memory used during the parse. */
struct demangle_info *info;
/* The result of the parse. */
struct demangle_component *tree;
/* Any temporary memory used during typedef replacement. */
struct obstack obstack;
};
/* Functions from cp-support.c. */
extern std::string cp_canonicalize_string (const char *string);
extern std::string cp_canonicalize_string_no_typedefs (const char *string);
typedef const char *(canonicalization_ftype) (struct type *, void *);
extern std::string cp_canonicalize_string_full (const char *string,
canonicalization_ftype *finder,
void *data);
extern char *cp_class_name_from_physname (const char *physname);
extern char *method_name_from_physname (const char *physname);
extern unsigned int cp_find_first_component (const char *name);
extern unsigned int cp_entire_prefix_len (const char *name);
extern char *cp_func_name (const char *full_name);
extern gdb::unique_xmalloc_ptr<char> cp_remove_params
(const char *demanged_name);
/* DEMANGLED_NAME is the name of a function, (optionally) including
parameters and (optionally) a return type. Return the name of the
function without parameters or return type, or NULL if we can not
parse the name. If COMPLETION_MODE is true, then tolerate a
non-existing or unbalanced parameter list. */
extern gdb::unique_xmalloc_ptr<char> cp_remove_params_if_any
(const char *demangled_name, bool completion_mode);
extern struct symbol **make_symbol_overload_list (const char *,
const char *);
extern struct symbol **make_symbol_overload_list_adl (struct type **arg_types,
int nargs,
const char *func_name);
extern struct type *cp_lookup_rtti_type (const char *name,
struct block *block);
/* Produce an unsigned hash value from SEARCH_NAME that is compatible
with cp_symbol_name_matches. Only the last component in
"foo::bar::function()" is considered for hashing purposes (i.e.,
the entire prefix is skipped), so that later on looking up for
"function" or "bar::function" in all namespaces is possible. */
extern unsigned int cp_search_name_hash (const char *search_name);
/* Implement the "la_get_symbol_name_matcher" language_defn method for
C++. */
extern symbol_name_matcher_ftype *cp_get_symbol_name_matcher
(const lookup_name_info &lookup_name);
/* Functions/variables from cp-namespace.c. */
extern int cp_is_in_anonymous (const char *symbol_name);
extern void cp_scan_for_anonymous_namespaces (const struct symbol *symbol,
struct objfile *objfile);
extern struct block_symbol cp_lookup_symbol_nonlocal
(const struct language_defn *langdef,
const char *name,
const struct block *block,
const domain_enum domain);
extern struct block_symbol
cp_lookup_symbol_namespace (const char *the_namespace,
const char *name,
const struct block *block,
const domain_enum domain);
extern struct block_symbol cp_lookup_symbol_imports_or_template
(const char *scope,
const char *name,
const struct block *block,
const domain_enum domain);
extern struct block_symbol
cp_lookup_nested_symbol (struct type *parent_type,
const char *nested_name,
const struct block *block,
const domain_enum domain);
struct type *cp_lookup_transparent_type (const char *name);
/* See description in cp-namespace.c. */
struct type *cp_find_type_baseclass_by_name (struct type *parent_type,
const char *name);
/* Functions from cp-name-parser.y. */
extern std::unique_ptr<demangle_parse_info> cp_demangled_name_to_comp
(const char *demangled_name, const char **errmsg);
extern gdb::unique_xmalloc_ptr<char> cp_comp_to_string
(struct demangle_component *result, int estimated_len);
extern void cp_merge_demangle_parse_infos (struct demangle_parse_info *,
struct demangle_component *,
struct demangle_parse_info *);
/* The list of "maint cplus" commands. */
extern struct cmd_list_element *maint_cplus_cmd_list;
/* A wrapper for bfd_demangle. */
char *gdb_demangle (const char *name, int options);
/* Like gdb_demangle, but suitable for use as la_sniff_from_mangled_name. */
int gdb_sniff_from_mangled_name (const char *mangled, char **demangled);
#endif /* CP_SUPPORT_H */