Remove symbol_matches_domain. This fixes

PR c++/16253.

symbol_matches_domain was permitting searches for a VAR_DOMAIN
symbol to also match STRUCT_DOMAIN symbols for languages like C++
where STRUCT_DOMAIN symbols also define a typedef of the same name,
e.g., "struct foo {}" introduces a typedef of the name "foo".

Problems occur if there exists both a VAR_DOMAIN and STRUCT_DOMAIN
symbol of the same name. Then it is essentially a race between which
symbol is found first. The other symbol is obscurred.
[This is a relatively common idiom: enum e { ... } e;]

This patchset moves this "language defines a typedef" logic to
lookup_symbol[_in_language], looking first for a symbol in the given
domain and falling back to searching STRUCT_DOMAIN when/if appropriate.

2014-04-14  Keith Seitz  <keiths@redhat.com>

	PR c++/16253
	* ada-lang.c (ada_symbol_matches_domain): Moved here and renamed
	from symbol_matches_domain in symtab.c. All local callers
	of symbol_matches_domain updated.
	(standard_lookup): If DOMAIN is VAR_DOMAIN and no symbol is found,
	search STRUCT_DOMAIN.
	(ada_find_any_type_symbol): Do not search STRUCT_DOMAIN
	independently.  standard_lookup will do that automatically.
	* cp-namespace.c (cp_lookup_symbol_nonlocal): Explain when/why
	VAR_DOMAIN searches may return a STRUCT_DOMAIN match.
	(cp_lookup_symbol_in_namespace): Likewise.
	If no VAR_DOMAIN symbol is found, search STRUCT_DOMAIN.
	(cp_lookup_symbol_exports): Explain when/why VAR_DOMAIN searches
	may return a STRUCT_DOMAIN match.
	(lookup_symbol_file): Search for the class name in STRUCT_DOMAIN.
	* cp-support.c: Include language.h.
	(inspect_type): Explicitly search STRUCT_DOMAIN before searching
	VAR_DOMAIN.
	* psymtab.c (match_partial_symbol): Compare the requested
	domain with the symbol's domain directly.
	(lookup_partial_symbol): Likewise.
	* symtab.c (lookup_symbol_in_language): Explain when/why
	VAR_DOMAIN searches may return a STRUCT_DOMAIN match.
	If no VAR_DOMAIN symbol is found, search STRUCT_DOMAIN for
	appropriate languages.
	(symbol_matches_domain): Renamed `ada_symbol_matches_domain'
	and moved to ada-lang.c
	(lookup_block_symbol): Explain that this function only returns
	symbol matching the requested DOMAIN.
	Compare the requested domain with the symbol's domain directly.
	(iterate_over_symbols): Compare the requested domain with the
	symbol's domain directly.
	* symtab.h (symbol_matches_domain): Remove.

2014-04-14  Keith Seitz  <keiths@redhat.com>

	PR c++/16253
	* gdb.cp/var-tag.cc: New file.
	* gdb.cp/var-tag.exp: New file.
	* gdb.dwarf2/dw2-ada-ffffffff.exp: Set the language to C++.
	* gdb.dwarf2/dw2-anon-mptr.exp: Likewise.
	* gdb.dwarf2/dw2-double-set-die-type.exp: Likewise.
	* gdb.dwarf2/dw2-inheritance.exp: Likewise.

2 files changed, 143 insertions, 0 deletions

diff --git a/gdb/testsuite/gdb.cp/var-tag.cc b/gdb/testsuite/gdb.cp/var-tag.cc
new file mode 100644
index 0000000..93b9caf
--- /dev/null
+++ b/gdb/testsuite/gdb.cp/var-tag.cc
@@ -0,0 +1,44 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2014 Free Software Foundation, Inc.
+
+   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/>.  */
+
+int global = 3;
+
+class C {
+public:
+  struct C1 {} C1;
+  enum E1 {a1, b1, c1} E1;
+  union U1 {int a1; char b1;} U1;
+
+  C () : E1 (b1) {}
+  void global (void) const {}
+  int f (void) const { global (); return 0; }
+} C;
+
+struct S {} S;
+enum E {a, b, c} E;
+union U {int a; char b;} U;
+
+class CC {} cc;
+struct SS {} ss;
+enum EE {ea, eb, ec} ee;
+union UU {int aa; char bb;} uu;
+
+int
+main (void)
+{
+  return C.f ();
+}
diff --git a/gdb/testsuite/gdb.cp/var-tag.exp b/gdb/testsuite/gdb.cp/var-tag.exp
new file mode 100644
index 0000000..7869fa2
--- /dev/null
+++ b/gdb/testsuite/gdb.cp/var-tag.exp
@@ -0,0 +1,99 @@
+# Copyright 2014 Free Software Foundation, Inc.
+
+# 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/>.
+
+# This file is part of the gdb testsuite
+
+# Test expressions in which variable names shadow tag names.
+
+if {[skip_cplus_tests]} { continue }
+
+standard_testfile .cc
+
+if {[prepare_for_testing $testfile.exp $testfile $srcfile {debug c++}]} {
+    return -1
+}
+
+proc do_global_tests {lang} {
+    if {$lang == "c"} {
+	set invalid_print "No symbol \"%s\" in current context."
+	set ptypefmt $invalid_print
+    } else {
+	set invalid_print "Attempt to use a type name as an expression"
+	set ptypefmt "type = (class|enum|union|struct) %s {.*}"
+    }
+
+    with_test_prefix $lang {
+	gdb_test_no_output "set language $lang"
+	gdb_test "ptype C" "type = class C {.*}"
+	gdb_test "print E" "= a"
+	gdb_test "ptype E" "type = enum E {.*}"
+	gdb_test "print S" "= {<No data fields>}"
+	gdb_test "ptype S" "type = struct S {.*}"
+	gdb_test "print U" "= {.*}"
+	gdb_test "ptype U" "type = union U {.*}"
+	gdb_test "print cc" "= {.*}"
+	gdb_test "ptype cc" "type = class CC {.*}"
+	gdb_test "print CC" [format $invalid_print "CC"]
+	gdb_test "ptype CC" [format $ptypefmt "CC"]
+	gdb_test "print ss" "= {<No data fields>}"
+	gdb_test "ptype ss" "type = struct SS {.*}"
+	gdb_test "print SS" [format $invalid_print "SS"]
+	gdb_test "ptype SS" [format $ptypefmt "SS"]
+	gdb_test "print ee" "= .*"
+	gdb_test "ptype ee" "type = enum EE {.*}"
+	gdb_test "print EE" [format $invalid_print "EE"]
+	gdb_test "ptype EE" [format $ptypefmt "EE"]
+	gdb_test "print uu" "= {.*}"
+	gdb_test "ptype uu" "type = union UU {.*}"
+	gdb_test "print UU" [format $invalid_print  "UU"]
+	gdb_test "ptype UU" [format $ptypefmt "UU"]
+    }
+}
+
+# First test expressions when there is no context.
+with_test_prefix "before start" {
+    do_global_tests c++
+    do_global_tests c
+}
+
+# Run to main and test again.
+if {![runto_main]} {
+    perror "couldn't run to main"
+    continue
+}
+
+with_test_prefix "in main" {
+    do_global_tests c++
+    do_global_tests c
+}
+
+# Finally run to C::f and test again
+gdb_breakpoint "C::f"
+gdb_continue_to_breakpoint "continue to C::f"
+with_test_prefix "in C::f" {
+    do_global_tests c++
+    do_global_tests c
+}
+
+# Another hard-to-guess-the-users-intent bug...
+# It would be really nice if we could query the user!
+with_test_prefix "global collision" {
+    gdb_test_no_output "set language c++"
+    setup_kfail "c++/16463" "*-*-*"
+    gdb_test "print global" "= 3"
+
+    # ... with a simple workaround:
+    gdb_test "print ::global" "= 3"
+}