Make strcmp_iw NOT ignore whitespace in the middle of tokens

currently "b func tion" manages to set a breakpoint at "function" !

All these years I had never noticed this, but now that the linespec
completer actually works, this easily happens by accident, with:

  "b func t<tab>"

expecting to get "thread", but getting instead:

  "b func tion"

...

Also, this:

  "b rettypefunc<int>"

manages to set a breakpoint on "rettype func<int>()".

These things happen due to strcmp_iw "magic".

Fix it by teaching strcmp_iw about when can it skip whitespace.  This
required handling user-defined operators, and scope operators,
complicating the code a bit, unfortunately.  I added unit tests for
all the corner cases I stumbled on, as I was developing this, and then
in the end wrote a testsuite testcase covering many of the same things
and more (to be added later).

gdb/ChangeLog:
2017-11-24  Pedro Alves  <palves@redhat.com>

	* cp-support.c (cp_symbol_name_matches_1): New, factored out from
	cp_fq_symbol_name_matches.  Pass language_cplus to
	strncmp_with_mode.
	(cp_fq_symbol_name_matches): Call cp_symbol_name_matches_1.
	(selftests::test_cp_symbol_name_cmp): New.
	(_initialize_cp_support): Register "cp_symbol_name_matches"
	selftests.
	* language.c (default_symbol_name_matcher): Pass language_minimal
	to strncmp_iw_with_mode.
	* utils.c: Include "cp-support.h" and <algorithm>.
	(valid_identifier_name_char, cp_skip_operator_token, skip_ws)
	(cp_is_operator): New functions.
	(strncmp_iw_with_mode): Use them.  Add language parameter.  Don't
	skip whitespace in the symbol name when the lookup name doesn't
	have spaces, and vice versa.
	(strncmp_iw, strcmp_iw): Pass language to strncmp_iw_with_mode.
	* utils.h (strncmp_iw_with_mode): Add language parameter.

1 files changed, 14 insertions, 4 deletions

diff --git a/gdb/utils.h b/gdb/utils.h
index e2fa430..dff4b17 100644
--- a/gdb/utils.h
+++ b/gdb/utils.h
@@ -48,17 +48,24 @@ enum class strncmp_iw_mode
 
 /* Helper for strcmp_iw and strncmp_iw.  Exported so that languages
    can implement both NORMAL and MATCH_PARAMS variants in a single
-   function and defer part of the work to strncmp_iw_with_mode.  */
+   function and defer part of the work to strncmp_iw_with_mode.
+   LANGUAGE is used to implement some context-sensitive
+   language-specific comparisons.  For example, for C++,
+   "string1=operator()" should not match "string2=operator" even in
+   MATCH_PARAMS mode.  */
 extern int strncmp_iw_with_mode (const char *string1,
 				 const char *string2,
 				 size_t string2_len,
-				 strncmp_iw_mode mode);
+				 strncmp_iw_mode mode,
+				 enum language language);
 
 /* Do a strncmp() type operation on STRING1 and STRING2, ignoring any
    differences in whitespace.  STRING2_LEN is STRING2's length.
    Returns 0 if STRING1 matches STRING2_LEN characters of STRING2,
    non-zero otherwise (slightly different than strncmp()'s range of
-   return values).  */
+   return values).  Note: passes language_minimal to
+   strncmp_iw_with_mode, and should therefore be avoided if a more
+   suitable language is available.  */
 extern int strncmp_iw (const char *string1, const char *string2,
 		       size_t string2_len);
 
@@ -70,7 +77,10 @@ extern int strncmp_iw (const char *string1, const char *string2,
    As an extra hack, string1=="FOO(ARGS)" matches string2=="FOO".
    This "feature" is useful when searching for matching C++ function
    names (such as if the user types 'break FOO', where FOO is a
-   mangled C++ function).  */
+   mangled C++ function).
+
+   Note: passes language_minimal to strncmp_iw_with_mode, and should
+   therefore be avoided if a more suitable language is available.  */
 extern int strcmp_iw (const char *string1, const char *string2);
 
 extern int strcmp_iw_ordered (const char *, const char *);