[PATCH] Put .gnu.linkonce.t.* owned jumptables into .gnu.linkonce.r.* instead of .rodata

[Jakub Jelinek <jakub at redhat dot com>]

Hi!

With the latest binutils, it is impossible to link many bigger C++ programs,
with errors like:
`.LAAAA' referenced in section `.rodata' of BBBB.o: defined in discarded section `.gnu.linkonce.t.CCCC' of DDDD.o
I know H.J.Lu posted a patch which did the support using section groups,
but that on the other side requires the very latest binutils,
while using .gnu.linkonce.r.* should IMHO work even with older binutils.

Is it enough like this or should function_readonly_data_section call
a target hook, whose default implementation would do what is in ATM
and targets whcih don't use default_unique_section_1 would override it
to simple readonly_data_section () call (or something else if they prefer)?

2004-08-11  Jakub Jelinek  <jakub@redhat.com>

	PR c++/16276
	* output.h (function_readonly_data_section): New prototype.
	* varasm.c (function_readonly_data_section): New function.
	* final.c (final_scan_insn): Call it instead of
	readonly_data_section.

	* g++.old-deja/g++.other/comdat4.C: New test.
	* g++.old-deja/g++.other/comdat4-aux.cc: New.

--- gcc/final.c.jj	2004-08-10 15:16:22.000000000 +0200
+++ gcc/final.c	2004-08-11 17:08:31.169998412 +0200
@@ -1966,7 +1966,7 @@ final_scan_insn (rtx insn, FILE *file, i
 		{
 		  int log_align;
 
-		  readonly_data_section ();
+		  function_readonly_data_section (current_function_decl);
 
 #ifdef ADDR_VEC_ALIGN
 		  log_align = ADDR_VEC_ALIGN (NEXT_INSN (insn));
--- gcc/varasm.c.jj	2004-08-05 12:06:06.000000000 +0200
+++ gcc/varasm.c	2004-08-11 17:59:49.359366083 +0200
@@ -541,6 +541,45 @@ function_section (tree decl)
     }
 }
 
+/* Switch to read-only data section associated with function DECL.
+
+   If DECL is NULL_TREE, switch to readonly_data_section ().  */
+
+void
+function_readonly_data_section (tree decl)
+{
+  if (decl != NULL_TREE && DECL_SECTION_NAME (decl))
+    {
+      const char *name = TREE_STRING_POINTER (DECL_SECTION_NAME (decl));
+
+      /* For .gnu.linkonce.t.foo we want to use .gnu.linkonce.r.foo.  */
+      if (DECL_ONE_ONLY (decl) && strncmp (name, ".gnu.linkonce.t.", 16) == 0)
+	{
+	  size_t len = strlen (name) + 1;
+	  char *rname = alloca (len);
+
+	  memcpy (rname, name, len);
+	  rname[14] = 'r';
+	  named_section_flags (rname, SECTION_LINKONCE);
+	  return;
+	}
+      /* For .text.foo we want to use .rodata.foo.  */
+      else if (flag_function_sections && flag_data_sections
+	       && strncmp (name, ".text.", 6) == 0)
+	{
+	  size_t len = strlen (name) + 1;
+	  char *rname = alloca (len + 2);
+
+	  memcpy (rname, ".rodata", 7);
+	  memcpy (rname + 7, name + 5, len - 5);
+	  named_section_flags (rname, 0);
+	  return;
+	}
+    }
+
+  readonly_data_section ();
+}
+
 /* Switch to section for variable DECL.  RELOC is the same as the
    argument to SELECT_SECTION.  */
 
--- gcc/output.h.jj	2004-07-09 13:50:55.000000000 +0200
+++ gcc/output.h	2004-08-11 17:01:49.665156409 +0200
@@ -214,6 +214,10 @@ extern void named_section (tree, const c
 /* Tell assembler to switch to the section for function DECL.  */
 extern void function_section (tree);
 
+/* Tell assembler to switch to the readonly data section associated
+   with function DECL.  */
+extern void function_readonly_data_section (tree);
+
 /* Tell assembler to switch to the section for string merging.  */
 extern void mergeable_string_section (tree, unsigned HOST_WIDE_INT,
 				      unsigned int);
--- gcc/testsuite/g++.old-deja/g++.other/comdat4.C.jj	2004-08-11 11:56:16.000000000 +0200
+++ gcc/testsuite/g++.old-deja/g++.other/comdat4.C	2004-08-11 18:47:45.770243910 +0200
@@ -0,0 +1,57 @@
+// PR c++/16276
+// { dg-do link }
+// { dg-additional-sources " comdat4-aux.cc" }
+// { dg-options "-O2" }
+
+extern void
+bar (int x);
+
+inline void
+foo (int i)
+{
+  switch (i)
+    {
+    case 3:
+    case 5:
+    case 6:
+    case 9:
+    case 15:
+      bar (1);
+      break;
+    case 2:
+    case 4:
+    case 7:
+    case 10:
+    case 11:
+    case 12:
+      bar (2);
+      break;
+    case 0:
+    case 1:
+    case 8:
+    case 13:
+    case 16:
+      bar (3);
+      break;
+    case 14:
+      bar (4);
+      break;
+    default:
+      bar (5);
+      break;
+    }
+}
+
+void *fooaddr = (void *) foo;
+
+void
+bar (int x)
+{
+  __asm __volatile ("" : : "r" (x));
+}
+
+int
+main (void)
+{
+  return 0;
+}
--- gcc/testsuite/g++.old-deja/g++.other/comdat4-aux.cc.jj	2004-08-11 11:56:19.000000000 +0200
+++ gcc/testsuite/g++.old-deja/g++.other/comdat4-aux.cc	2004-08-11 11:56:47.000000000 +0200
@@ -0,0 +1,40 @@
+extern void
+bar (int x);
+
+inline void
+foo (int i)
+{
+  switch (i)
+    {
+    case 3:
+    case 5:
+    case 6:
+    case 9:
+    case 15:
+      bar (1);
+      break;
+    case 2:
+    case 4:
+    case 7:
+    case 10:
+    case 11:
+    case 12:
+      bar (2);
+      break;
+    case 0:
+    case 1:
+    case 8:
+    case 13:
+    case 16:
+      bar (3);
+      break;
+    case 14:
+      bar (4);
+      break;
+    default:
+      bar (5);
+      break;
+    }
+}
+
+void *fooaddr2 = (void *) foo;

	Jakub