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.

1 files changed, 24 insertions, 1 deletions

diff --git a/gdb/cp-support.c b/gdb/cp-support.c
index 2379b54..91533e8 100644
--- a/gdb/cp-support.c
+++ b/gdb/cp-support.c
@@ -35,6 +35,7 @@
 #include "expression.h"
 #include "value.h"
 #include "cp-abi.h"
+#include "language.h"
 
 #include "safe-ctype.h"
 
@@ -177,7 +178,29 @@ inspect_type (struct demangle_parse_info *info,
   sym = NULL;
   TRY_CATCH (except, RETURN_MASK_ALL)
   {
-    sym = lookup_symbol (name, 0, VAR_DOMAIN, 0);
+    /* It is not legal to have a typedef and tag name of the same
+       name in C++.  However, anonymous composite types that are defined
+       with a typedef ["typedef struct {...} anonymous_struct;"] WILL
+       have symbols for a TYPE_CODE_TYPEDEF (in VAR_DOMAIN) and a
+       TYPE_CODE_STRUCT (in STRUCT_DOMAIN).
+
+       If VAR_DOMAIN is searched first, it will return the TYPEDEF symbol,
+       and this function will never output the definition of the typedef,
+       since type_print is called below with SHOW = -1. [The typedef hash
+       is never initialized/used when SHOW <= 0 -- and the finder
+       (find_typedef_for_canonicalize) will always return NULL as a result.]
+
+       Consequently, type_print will eventually keep calling this function
+       to replace the typedef (via
+       print_name_maybe_canonical/cp_canonicalize_full).  This leads to
+       infinite recursion.
+
+       This can all be safely avoid by explicitly searching STRUCT_DOMAIN
+       first to find the structure definition.  */
+    if (current_language->la_language == language_cplus)
+      sym = lookup_symbol (name, 0, STRUCT_DOMAIN, 0);
+    if (sym == NULL)
+      sym = lookup_symbol (name, 0, VAR_DOMAIN, NULL);
   }
 
   if (except.reason >= 0 && sym != NULL)