Re: version scripts and default/C language mangling

[Mike Frysinger <vapier at gentoo dot org>]

On Monday, July 12, 2010 04:05:02 Ian Lance Taylor wrote:
> Mike Frysinger writes:
> > first, i'm asking what the default language is for the version script. 
> > i'd expect the answer to be "no language" which means the symbols would
> > be matched against any random leading char a target introduces.  i'm
> > also OK with the answer "C language", although it does prevent working
> > with symbols that lack the prefix char because they were created via
> > assembly code.
> 
> The default language is "C".  I think the right thing to do in that case
> is strip the leading character if present, and otherwise do nothing.
> That is what bfd_demangle does.

works for me

> > yes, but presumably changing ldlang.c to consider that value is
> > unacceptable. the current parsing code is also not given the current
> > bfd, only bfd_elf_version_expr structures, and those dont contain links
> > back to a bfd that i can see.  unless there is a way to get the current
> > "active" bfd ?  then it should be easy to drop in support in
> > lang_vers_match() with the function bfd_get_symbol_leading_char() you
> > pointed out.
> 
> I think it would be entirely reasonable to change lang_vers_match to
> take a BFD parameter, and change the corresponding calling code in
> bfd/elflink.c.  Or, the output BFD is always available in
> link_info.output_bfd.

since the existing bfd_demangle user in this file is using
link_info.output_bfd, i'm going to roll with that.

how does the attached patch look ?  seems to fix things with Blackfin targets,
and no regressions are seen with x86_64-linux-gnu and bfin-linux-uclibc.

i'll do some more system wide testing in the mean time ...
-mike

diff --git a/ld/ldlang.c b/ld/ldlang.c
index 9c4e17b..5875ef6 100644
--- a/ld/ldlang.c
+++ b/ld/ldlang.c
@@ -7179,19 +7179,28 @@ lang_vers_match (struct bfd_elf_version_expr_head *head,
 		 struct bfd_elf_version_expr *prev,
 		 const char *sym)
 {
+  const char *c_sym;
   const char *cxx_sym = sym;
   const char *java_sym = sym;
   struct bfd_elf_version_expr *expr = NULL;
+  enum demangling_styles curr_style;
+
+  curr_style = CURRENT_DEMANGLING_STYLE;
+  c_sym = bfd_demangle (link_info.output_bfd, sym, DMGL_NO_OPTS);
+  if (!c_sym)
+    c_sym = sym;
+  cplus_demangle_set_style (curr_style);
 
   if (head->mask & BFD_ELF_VERSION_CXX_TYPE)
     {
-      cxx_sym = cplus_demangle (sym, DMGL_PARAMS | DMGL_ANSI);
+      cxx_sym = bfd_demangle (link_info.output_bfd, sym,
+			      DMGL_PARAMS | DMGL_ANSI);
       if (!cxx_sym)
 	cxx_sym = sym;
     }
   if (head->mask & BFD_ELF_VERSION_JAVA_TYPE)
     {
-      java_sym = cplus_demangle (sym, DMGL_JAVA);
+      java_sym = bfd_demangle (link_info.output_bfd, sym, DMGL_JAVA);
       if (!java_sym)
 	java_sym = sym;
     }
@@ -7205,10 +7214,10 @@ lang_vers_match (struct bfd_elf_version_expr_head *head,
 	case 0:
 	  if (head->mask & BFD_ELF_VERSION_C_TYPE)
 	    {
-	      e.pattern = sym;
+	      e.pattern = c_sym;
 	      expr = (struct bfd_elf_version_expr *)
                   htab_find ((htab_t) head->htab, &e);
-	      while (expr && strcmp (expr->pattern, sym) == 0)
+	      while (expr && strcmp (expr->pattern, c_sym) == 0)
 		if (expr->mask == BFD_ELF_VERSION_C_TYPE)
 		  goto out_ret;
 		else
@@ -7266,12 +7275,14 @@ lang_vers_match (struct bfd_elf_version_expr_head *head,
       else if (expr->mask == BFD_ELF_VERSION_CXX_TYPE)
 	s = cxx_sym;
       else
-	s = sym;
+	s = c_sym;
       if (fnmatch (expr->pattern, s, 0) == 0)
 	break;
     }
 
  out_ret:
+  if (c_sym != sym)
+    free ((char *) c_sym);
   if (cxx_sym != sym)
     free ((char *) cxx_sym);
   if (java_sym != sym)

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