Move logic out of symbol_find_demangled_name

This patch moves most of the demangling logic out of
symbol_find_demangled_name into the various language_defn objects.

The simplest way to do this seemed to be to add a new method to
language_defn.  This is shame given the existing la_demangle, but
given Ada's unusual needs, and the differing demangling options
between languages, la_demangle didn't seem to fit.

In order to make this work, I made enum language order-sensitive.
This helps preserve the current ordering of demangling operations.

2016-06-23  Tom Tromey  <tom@tromey.com>

	* symtab.c (symbol_find_demangled_name): Loop over languages and
	use language_sniff_from_mangled_name.
	* rust-lang.c (rust_sniff_from_mangled_name): New function.
	(rust_language_defn): Update.
	* p-lang.c (pascal_language_defn): Update.
	* opencl-lang.c (opencl_language_defn): Update.
	* objc-lang.c (objc_sniff_from_mangled_name): New function.
	(objc_language_defn): Update.
	* m2-lang.c (m2_language_defn): Update.
	* language.h (struct language_defn) <la_sniff_from_mangled_name>: New
	field.
	(language_sniff_from_mangled_name): Declare.
	* language.c (language_sniff_from_mangled_name): New function.
	(unknown_language_defn, auto_language_defn, local_language_defn):
	Update.
	* jv-lang.c (java_sniff_from_mangled_name): New function.
	(java_language_defn): Use it.
	* go-lang.c (go_sniff_from_mangled_name): New function.
	(go_language_defn): Use it.
	* f-lang.c (f_language_defn): Update.
	* defs.h (enum language): Reorder.
	* d-lang.c (d_sniff_from_mangled_name): New function.
	(d_language_defn): Use it.
	* cp-support.h (gdb_sniff_from_mangled_name): Declare.
	* cp-support.c (gdb_sniff_from_mangled_name): New function.
	* c-lang.c (c_language_defn, cplus_language_defn)
	(asm_language_defn, minimal_language_defn): Update.
	* ada-lang.c (ada_sniff_from_mangled_name): New function.
	(ada_language_defn): Use it.

1 files changed, 40 insertions, 0 deletions

diff --git a/gdb/ada-lang.c b/gdb/ada-lang.c
index 796dc65..b22b7ac 100644
--- a/gdb/ada-lang.c
+++ b/gdb/ada-lang.c
@@ -1452,6 +1452,45 @@ ada_la_decode (const char *encoded, int options)
   return xstrdup (ada_decode (encoded));
 }
 
+/* Implement la_sniff_from_mangled_name for Ada.  */
+
+static int
+ada_sniff_from_mangled_name (const char *mangled, char **out)
+{
+  const char *demangled = ada_decode (mangled);
+
+  *out = NULL;
+
+  if (demangled != mangled && demangled != NULL && demangled[0] != '<')
+    {
+      /* Set the gsymbol language to Ada, but still return 0.
+	 Two reasons for that:
+
+	 1. For Ada, we prefer computing the symbol's decoded name
+	 on the fly rather than pre-compute it, in order to save
+	 memory (Ada projects are typically very large).
+
+	 2. There are some areas in the definition of the GNAT
+	 encoding where, with a bit of bad luck, we might be able
+	 to decode a non-Ada symbol, generating an incorrect
+	 demangled name (Eg: names ending with "TB" for instance
+	 are identified as task bodies and so stripped from
+	 the decoded name returned).
+
+	 Returning 1, here, but not setting *DEMANGLED, helps us get a
+	 little bit of the best of both worlds.  Because we're last,
+	 we should not affect any of the other languages that were
+	 able to demangle the symbol before us; we get to correctly
+	 tag Ada symbols as such; and even if we incorrectly tagged a
+	 non-Ada symbol, which should be rare, any routing through the
+	 Ada language should be transparent (Ada tries to behave much
+	 like C/C++ with non-Ada symbols).  */
+      return 1;
+    }
+
+  return 0;
+}
+
 /* Returns non-zero iff SYM_NAME matches NAME, ignoring any trailing
    suffixes that encode debugging information or leading _ada_ on
    SYM_NAME (see is_name_suffix commentary for the debugging
@@ -14086,6 +14125,7 @@ const struct language_defn ada_language_defn = {
   ada_lookup_symbol_nonlocal,   /* Looking up non-local symbols.  */
   basic_lookup_transparent_type,        /* lookup_transparent_type */
   ada_la_decode,                /* Language specific symbol demangler */
+  ada_sniff_from_mangled_name,
   NULL,                         /* Language specific
 				   class_name_from_physname */
   ada_op_print_tab,             /* expression operators for printing */