Re: [PATCH] Make mergeable read-only sections per-function, if requested.

[Segher Boessenkool]

On Thu, May 07, 2015 at 10:15:08AM +0200, Marek Polacek wrote:
> > +const char *
> > +function_mergeable_rodata_prefix (void)
> 
> This function needs a comment.

And much more importantly, I forgot to make it static.  Fixed.

> > +{
> > +  section *s = targetm.asm_out.function_rodata_section 
> > (current_function_decl);
> > +  if (SECTION_STYLE (s) == SECTION_NAMED)
> > +    return s->named.name;
> > +      else
> > +    return targetm.asm_out.mergeable_rodata_prefix;
> 
> else is wrongly formatted.

Huh, how did I do this.  Fixed.

Thanks for the review.  New patch:

- - -

Make mergeable read-only sections per-function, if requested.

Currently GCC does not put mergeable read-only data in a per-function
section, so the --gc-sections linker option does not do much for such
data.  Fix that.

Bootstrapped and tested on powerpc64-linux; no regressions.

Is this okay for trunk?


Segher


2015-05-07  Segher Boessenkool  <seg...@kernel.crashing.org>

        PR middle-end/192
        PR middle-end/54303
        * varasm.c (function_mergeable_rodata_prefix): New function.
        (mergeable_string_section): Use it.
        (mergeable_constant_section): Use it.
---
 gcc/varasm.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/gcc/varasm.c b/gcc/varasm.c
index 62d5163..11cb2c5 100644
--- a/gcc/varasm.c
+++ b/gcc/varasm.c
@@ -783,6 +783,18 @@ default_no_function_rodata_section (tree decl 
ATTRIBUTE_UNUSED)
   return readonly_data_section;
 }
 
+/* A subroutine of mergeable_string_section and mergeable_constant_section.  */
+
+static const char *
+function_mergeable_rodata_prefix (void)
+{
+  section *s = targetm.asm_out.function_rodata_section (current_function_decl);
+  if (SECTION_STYLE (s) == SECTION_NAMED)
+    return s->named.name;
+  else
+    return targetm.asm_out.mergeable_rodata_prefix;
+}
+
 /* Return the section to use for string merging.  */
 
 static section *
@@ -804,7 +816,7 @@ mergeable_string_section (tree decl ATTRIBUTE_UNUSED,
       const char *str;
       HOST_WIDE_INT i;
       int j, unit;
-      const char *prefix = targetm.asm_out.mergeable_rodata_prefix;
+      const char *prefix = function_mergeable_rodata_prefix ();
       char *name = (char *) alloca (strlen (prefix) + 30);
 
       mode = TYPE_MODE (TREE_TYPE (TREE_TYPE (decl)));
@@ -857,7 +869,7 @@ mergeable_constant_section (machine_mode mode 
ATTRIBUTE_UNUSED,
       && align <= 256
       && (align & (align - 1)) == 0)
     {
-      const char *prefix = targetm.asm_out.mergeable_rodata_prefix;
+      const char *prefix = function_mergeable_rodata_prefix ();
       char *name = (char *) alloca (strlen (prefix) + 30);
 
       sprintf (name, "%s.cst%d", prefix, (int) (align / 8));
-- 
1.8.1.4