RFA: tweak minsyms check for GNU v3 symbols

[Daniel Jacobowitz <drow@mvista.com>]

This is based on a patch that Kris Warkentin sent out last October, that's
been sitting in my inbox for a while.  It's a little more efficient but the
idea is the same.  Right now, we consider any _Z symbol to imply GNU v3; but
what we really want is for any _Z symbol _which demangled successfully_ to
imply GNU v3.  _Zero is the QNX example of a false positive for the current
check.  It's still not perfect, but it's much better.

Tested in combination with the "set cp-abi" patch, to make sure it behaved
properly; sure enough:
  - we still get GNU v3 for a v3 application
  - we no longer get GNU v3 for a v2 application containing _Zero (before
    the patch, we did).

Is this OK?

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer

2003-03-02  Daniel Jacobowitz  <drow@mvista.com>

	* minsyms.c (install_minimal_symbols): Only switch to gnu-v3 mode
	if the linkage name demangled successfully.

Index: minsyms.c
===================================================================
RCS file: /cvs/src/src/gdb/minsyms.c,v
retrieving revision 1.26
diff -u -p -r1.26 minsyms.c
--- minsyms.c	25 Feb 2003 21:36:18 -0000	1.26
+++ minsyms.c	2 Mar 2003 18:38:28 -0000
@@ -918,8 +918,14 @@ install_minimal_symbols (struct objfile 
 
 	for (i = 0; i < mcount; i++)
 	  {
-	    const char *name = DEPRECATED_SYMBOL_NAME (&objfile->msymbols[i]);
-	    if (name[0] == '_' && name[1] == 'Z')
+	    /* If a symbol's name starts with _Z and was successfully
+	       demangled, then we can assume we've found a GNU v3 symbol.
+	       For now we set the C++ ABI globally; if the user is
+	       mixing ABIs then the user will need to "set cp-abi"
+	       manually.  */
+	    const char *name = SYMBOL_LINKAGE_NAME (&objfile->msymbols[i]);
+	    if (name[0] == '_' && name[1] == 'Z'
+		&& SYMBOL_DEMANGLED_NAME (&objfile->msymbols[i]) != NULL)
 	      {
 		switch_to_cp_abi ("gnu-v3");
 		break;