[binutils-gdb] Fix gdb.ada/complete.exp's "complete break ada" test (PR gdb/22670)

[Pedro Alves <palves at sourceware dot org>]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=d4c2a405cb7535d25b88e9b8dad0e557242950ca

commit d4c2a405cb7535d25b88e9b8dad0e557242950ca
Author: Pedro Alves <palves@redhat.com>
Date:   Wed Jan 10 20:38:07 2018 +0000

    Fix gdb.ada/complete.exp's "complete break ada" test (PR gdb/22670)
    
    This patch fixes the regression covered by the test added by:
    
        commit 344420da6beac1e0b2f7964e7101f8dcdb509b0d
        Date: Thu Jan 4 03:30:37 2018 -0500
        Subject: Add "complete break ada" test to gdb.ada/complete.exp
    
    The regression had been introduced by:
    
        commit b5ec771e60c1a0863e51eb491c85c674097e9e13
        Date:   Wed Nov 8 14:22:32 2017 +0000
        Subject: Introduce lookup_name_info and generalize Ada's FULL/WILD name matching
    
    The gist of it is that linespec completion in Ada mode is generating
    additional matches that should not appear in the match list
    (internally generated symbols, or symbols that should be enclosed
    between "<...>").  These extraneous entries have uppercase characters, such as:
    
        break ada__stringsS
        break ada__strings__R11s
        [etc]
    
    These matches come from minimal symbols.  The problem is that Ada
    minsyms end up with no language set (language_auto), and thus we end
    up using the generic symbol name matcher for those instead of Ada's.
    We already had a special case for in compare_symbol_name to handle
    this, but it was limited to expressions, while the case at hand is
    completing a linespec.  Fix this by applying the special case to
    linespec completion as well.  I.e., remove the EXPRESSION check from
    compare_symbol_name.  That alone turns out to not be sufficient still
    -- GDB would still show a couple entries that shouldn't be there:
    
    ~~
        break ada__exceptions__exception_data__append_info_exception_name__2Xn
        break ada__exceptions__exception_data__exception_name_length__2Xn
    ~~
    
    The reason is that these minimal symbols end up with their language
    set to language_cplus / C++, because those encoded names manage to
    demangle successfully as C++ symbols (using an old C++ mangling
    scheme):
    
      $ echo ada__exceptions__exception_data__append_info_exception_name__2Xn | c++filt
      Xn::ada__exceptions__exception_data__append_info_exception_name(void)
    
    It's unfortunate that Ada's encoding scheme doesn't start with some
    unique prefix like "_Z" in the C++ Itanium ABI mangling scheme.  For
    now, paper over that by treating C++ minsyms as Ada minsyms.
    
    gdb/ChangeLog:
    2018-01-10  Pedro Alves  <palves@redhat.com>
    
            PR gdb/22670
    	* ada-lang.c (ada_collect_symbol_completion_matches): If the
    	minsym's language is language_auto or language_cplus, pass down
    	language_ada instead.
    	* symtab.c (compare_symbol_name): Don't frob symbol language here.
    
    gdb/testsuite/ChangeLog:
    2018-01-10  Pedro Alves  <palves@redhat.com>
    
            PR gdb/22670
    	* gdb.ada/complete.exp ("complete break ada"): Replace kfail with
    	a fail.

Diff:
---
 gdb/ChangeLog                      |  8 ++++++++
 gdb/ada-lang.c                     | 19 ++++++++++++++++++-
 gdb/symtab.c                       | 16 +---------------
 gdb/testsuite/ChangeLog            |  6 ++++++
 gdb/testsuite/gdb.ada/complete.exp |  4 ++--
 5 files changed, 35 insertions(+), 18 deletions(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index f845705..a0df1a3 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,6 +1,14 @@
 2018-01-10  Pedro Alves  <palves@redhat.com>
 
 	PR gdb/22670
+	* ada-lang.c (ada_collect_symbol_completion_matches): If the
+	minsym's language is language_auto or language_cplus, pass down
+	language_ada instead.
+	* symtab.c (compare_symbol_name): Don't frob symbol language here.
+
+2018-01-10  Pedro Alves  <palves@redhat.com>
+
+	PR gdb/22670
 	* minsyms.c (linkage_name_str): New function.
 	(iterate_over_minimal_symbols): Use it.
 
diff --git a/gdb/ada-lang.c b/gdb/ada-lang.c
index 622cfd0..ab10838 100644
--- a/gdb/ada-lang.c
+++ b/gdb/ada-lang.c
@@ -6499,8 +6499,25 @@ ada_collect_symbol_completion_matches (completion_tracker &tracker,
     if (completion_skip_symbol (mode, msymbol))
       continue;
 
+    language symbol_language = MSYMBOL_LANGUAGE (msymbol);
+
+    /* Ada minimal symbols won't have their language set to Ada.  If
+       we let completion_list_add_name compare using the
+       default/C-like matcher, then when completing e.g., symbols in a
+       package named "pck", we'd match internal Ada symbols like
+       "pckS", which are invalid in an Ada expression, unless you wrap
+       them in '<' '>' to request a verbatim match.
+
+       Unfortunately, some Ada encoded names successfully demangle as
+       C++ symbols (using an old mangling scheme), such as "name__2Xn"
+       -> "Xn::name(void)" and thus some Ada minimal symbols end up
+       with the wrong language set.  Paper over that issue here.  */
+    if (symbol_language == language_auto
+	|| symbol_language == language_cplus)
+      symbol_language = language_ada;
+
     completion_list_add_name (tracker,
-			      MSYMBOL_LANGUAGE (msymbol),
+			      symbol_language,
 			      MSYMBOL_LINKAGE_NAME (msymbol),
 			      lookup_name, text, word);
   }
diff --git a/gdb/symtab.c b/gdb/symtab.c
index 146dc2e..2fe2496 100644
--- a/gdb/symtab.c
+++ b/gdb/symtab.c
@@ -4704,21 +4704,7 @@ compare_symbol_name (const char *symbol_name, language symbol_language,
 		     const lookup_name_info &lookup_name,
 		     completion_match_result &match_res)
 {
-  const language_defn *lang;
-
-  /* If we're completing for an expression and the symbol doesn't have
-     an explicit language set, fallback to the current language.  Ada
-     minimal symbols won't have their language set to Ada, for
-     example, and if we compared using the default/C-like matcher,
-     then when completing e.g., symbols in a package named "pck", we'd
-     match internal Ada symbols like "pckS", which are invalid in an
-     Ada expression, unless you wrap them in '<' '>' to request a
-     verbatim match.  */
-  if (symbol_language == language_auto
-      && lookup_name.match_type () == symbol_name_match_type::EXPRESSION)
-    lang = current_language;
-  else
-    lang = language_def (symbol_language);
+  const language_defn *lang = language_def (symbol_language);
 
   symbol_name_matcher_ftype *name_match
     = language_get_symbol_name_matcher (lang, lookup_name);
diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index ec763fc..7a2ffb6 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,6 +1,12 @@
 2018-01-10  Pedro Alves  <palves@redhat.com>
 
 	PR gdb/22670
+	* gdb.ada/complete.exp ("complete break ada"): Replace kfail with
+	a fail.
+
+2018-01-10  Pedro Alves  <palves@redhat.com>
+
+	PR gdb/22670
 	* gdb.ada/bp_c_mixed_case.exp: Remove setup_kfail calls.
 
 2018-01-08  Simon Marchi  <simon.marchi@ericsson.com>
diff --git a/gdb/testsuite/gdb.ada/complete.exp b/gdb/testsuite/gdb.ada/complete.exp
index c1f22c2..cb9e4ae 100644
--- a/gdb/testsuite/gdb.ada/complete.exp
+++ b/gdb/testsuite/gdb.ada/complete.exp
@@ -212,7 +212,7 @@ test_gdb_complete "ambiguous_func" \
 # However, we want to sanity-check each one of them, knowing that
 # each result should start with "break ada" and that the proposed
 # completion should look like a valid symbol name (in particular,
-# no uppercase letters...).
+# no uppercase letters...).  See gdb/22670.
 
 gdb_test_no_output "set max-completions unlimited"
 
@@ -222,6 +222,6 @@ gdb_test_multiple "$test" $test {
         pass $test
     }
     -re "\[A-Z\].*$gdb_prompt $" {
-        kfail gdb/22670 $test
+	fail "$test (gdb/22670)"
     }
 }