Breakpoints in symbols with ABI tags (PR c++/19436)

Trying to set a breakpoint in a function with an ABI tag does not work
currently.  E.g., debugging gdb itself, we see this with the
"string_printf" function:

 (top-gdb) b string_print                               [TAB]
 (top-gdb) b string_printf[abi:cxx11](char const*, ...) [RET]
 No source file named string_printf[abi.
 Make breakpoint pending on future shared library load? (y or [n])

Quoting doesn't help:
 (top-gdb) b 'string_printf[abi:cxx11]'(char const*, ...)
 malformed linespec error: unexpected string, "(char const*, ...)"
 (top-gdb) b 'string_printf[abi:cxx11](char const*, ...)'
 No source file named string_printf[abi.
 Make breakpoint pending on future shared library load? (y or [n]) n

This patch fixes this, and takes it a bit further.

The actual symbol name as demangled by libiberty's demangler is really

 string_printf[abi:cxx11](char const*, ...)

however, this patch makes it possible to set the breakpoint with

 string_printf(char const*, ...)

too.  I.e., ignoring the ABI tag.

And to match, it teaches the completer to complete the symbol name
without the ABI tag, i.e.,

  "string_pri<TAB>"  -> "string_printf(char const*, ...)"

If however, you really want to break on a symbol with the tag, then
you simply start writing the tag, and GDB will preserve it, like:

  "string_printf[a<TAB>"  -> "string_printf[abi:cxx11](char const*, ...)"

Grows the gdb.linespec/ tests like this:

  -# of expected passes           8977
  +# of expected passes           9176

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

	PR c++/19436
	* NEWS: Mention setting breakpoints on functions with C++ ABI
	tags.
	* completer.h (completion_match_for_lcd) <match,
	mark_ignored_range>: New methods.
	<finish>: Consider ignored ranges.
	<clear>: Clear ignored ranges.
	<m_ignored_ranges, m_finished_storage>: New fields.
	* cp-support.c (cp_search_name_hash): Ignore ABI tags.
	(cp_symbol_name_matches_1, cp_fq_symbol_name_matches): Pass the
	completion_match_for_lcd pointer to strncmp_iw_with_mode.
	(test_cp_symbol_name_cmp): Add [abi:...] tags unit tests.
	* language.c (default_symbol_name_matcher): Pass the
	completion_match_for_lcd pointer to strncmp_iw_with_mode.
	* linespec.c (linespec_lexer_lex_string): Don't tokenize ABI tags.
	* utils.c (skip_abi_tag): New function.
	(strncmp_iw_with_mode): Add completion_match_for_lcd parameter.
	Handle ABI tags.
	* utils.h (strncmp_iw_with_mode): Add completion_match_for_lcd
	parameter.

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

	PR c++/19436
	* gdb.linespec/cpls-abi-tag.cc: New file.
	* gdb.linespec/cpls-abi-tag.exp: New file.

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

	PR c++/19436
	* gdb.texinfo (Debugging C Plus Plus): Document setting
	breakpoints in functions with ABI tags.

1 files changed, 49 insertions, 4 deletions

diff --git a/gdb/cp-support.c b/gdb/cp-support.c
index 172d8219f4..34a84395f4 100644
--- a/gdb/cp-support.c
+++ b/gdb/cp-support.c
@@ -1629,7 +1629,23 @@ cp_search_name_hash (const char *search_name)
   if (prefix_len != 0)
     search_name += prefix_len + 2;
 
-  return default_search_name_hash (search_name);
+  unsigned int hash = 0;
+  for (const char *string = search_name; *string != '\0'; ++string)
+    {
+      string = skip_spaces (string);
+
+      if (*string == '(')
+	break;
+
+      /* Ignore ABI tags such as "[abi:cxx11].  */
+      if (*string == '['
+	  && startswith (string + 1, "abi:")
+	  && string[5] != ':')
+	break;
+
+      hash = SYMBOL_HASH_NEXT (hash, *string);
+    }
+  return hash;
 }
 
 /* Helper for cp_symbol_name_matches (i.e., symbol_name_matcher_ftype
@@ -1674,11 +1690,13 @@ cp_symbol_name_matches_1 (const char *symbol_search_name,
 			  completion_match_result *comp_match_res)
 {
   const char *sname = symbol_search_name;
+  completion_match_for_lcd *match_for_lcd
+    = (comp_match_res != NULL ? &comp_match_res->match_for_lcd : NULL);
 
   while (true)
     {
       if (strncmp_iw_with_mode (sname, lookup_name, lookup_name_len,
-				mode, language_cplus) == 0)
+				mode, language_cplus, match_for_lcd) == 0)
 	{
 	  if (comp_match_res != NULL)
 	    {
@@ -1728,14 +1746,15 @@ cp_fq_symbol_name_matches (const char *symbol_search_name,
 {
   /* Get the demangled name.  */
   const std::string &name = lookup_name.cplus ().lookup_name ();
-
+  completion_match_for_lcd *match_for_lcd
+    = (comp_match_res != NULL ? &comp_match_res->match_for_lcd : NULL);
   strncmp_iw_mode mode = (lookup_name.completion_mode ()
 			  ? strncmp_iw_mode::NORMAL
 			  : strncmp_iw_mode::MATCH_PARAMS);
 
   if (strncmp_iw_with_mode (symbol_search_name,
 			    name.c_str (), name.size (),
-			    mode, language_cplus) == 0)
+			    mode, language_cplus, match_for_lcd) == 0)
     {
       if (comp_match_res != NULL)
 	comp_match_res->set_match (symbol_search_name);
@@ -1950,6 +1969,32 @@ test_cp_symbol_name_matches ()
   CHECK_NOT_MATCH_C ("foo::function()", "::function()");
   CHECK_NOT_MATCH_C ("foo::function(int)", "::function()");
   CHECK_NOT_MATCH_C ("foo::function(int)", "::function(int)");
+
+  /* Test ABI tag matching/ignoring.  */
+
+  /* If the symbol name has an ABI tag, but the lookup name doesn't,
+     then the ABI tag in the symbol name is ignored.  */
+  CHECK_MATCH_C ("function[abi:foo]()", "function");
+  CHECK_MATCH_C ("function[abi:foo](int)", "function");
+  CHECK_MATCH_C ("function[abi:foo]()", "function ()");
+  CHECK_NOT_MATCH_C ("function[abi:foo]()", "function (int)");
+
+  CHECK_MATCH_C ("function[abi:foo]()", "function[abi:foo]");
+  CHECK_MATCH_C ("function[abi:foo](int)", "function[abi:foo]");
+  CHECK_MATCH_C ("function[abi:foo]()", "function[abi:foo] ()");
+  CHECK_MATCH_C ("function[abi:foo][abi:bar]()", "function");
+  CHECK_MATCH_C ("function[abi:foo][abi:bar](int)", "function");
+  CHECK_MATCH_C ("function[abi:foo][abi:bar]()", "function[abi:foo]");
+  CHECK_MATCH_C ("function[abi:foo][abi:bar](int)", "function[abi:foo]");
+  CHECK_MATCH_C ("function[abi:foo][abi:bar]()", "function[abi:foo] ()");
+  CHECK_NOT_MATCH_C ("function[abi:foo][abi:bar]()", "function[abi:foo] (int)");
+
+  CHECK_MATCH_C ("function  [abi:foo][abi:bar] ( )", "function [abi:foo]");
+
+  /* If the symbol name does not have an ABI tag, while the lookup
+     name has one, then there's no match.  */
+  CHECK_NOT_MATCH_C ("function()", "function[abi:foo]()");
+  CHECK_NOT_MATCH_C ("function()", "function[abi:foo]");
 }
 
 /* If non-NULL, return STR wrapped in quotes.  Otherwise, return a