Relocatable read-only section support for absolute jump table

This patch puts absolute jump tables into a relocatable read-only section
if they are on ELF target and relocation is supported.

gcc/ChangeLog:

	* final.c (final_scan_insn_1): Set jump table relocatable as the
	second argument of targetm.asm_out.function_rodata_section.
	* output.h (default_function_rodata_section,
	default_no_function_rodata_section): Add the second argument to the
	declarations.
	* target.def (function_rodata_section): Change the doc and add
	the second argument.
	* doc/tm.texi: Regenerate.
	* varasm.c (jumptable_relocatable): Implement.
	(default_function_rodata_section): Add the second argument
	and the support for relocatable read only sections.
	(default_no_function_rodata_section): Add the second argument.
	(function_mergeable_rodata_prefix): Set the second argument to false.
	* config/mips/mips.c (mips_function_rodata_section): Add the second
	arugment and set it to false.
	* config/s390/s390.c (targetm.asm_out.function_rodata_section): Set
	the second argument to false.
	* config/s390/s390.md: Likewise.

1 files changed, 20 insertions, 2 deletions

diff --git a/gcc/final.c b/gcc/final.c
index 80423d1..fc9a05e 100644
--- a/gcc/final.c
+++ b/gcc/final.c
@@ -81,6 +81,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "rtl-iter.h"
 #include "print-rtl.h"
 #include "function-abi.h"
+#include "common/common-target.h"
 
 #ifdef XCOFF_DEBUGGING_INFO
 #include "xcoffout.h"		/* Needed for external data declarations.  */
@@ -2154,6 +2155,21 @@ asm_show_source (const char *filename, int linenum)
   fputc ('\n', asm_out_file);
 }
 
+/* Judge if an absolute jump table is relocatable.  */
+
+bool
+jumptable_relocatable (void)
+{
+  bool relocatable = false;
+
+  if (!CASE_VECTOR_PC_RELATIVE
+      && !targetm.asm_out.generate_pic_addr_diff_vec ()
+      && targetm_common.have_named_sections)
+     relocatable = targetm.asm_out.reloc_rw_mask ();
+
+  return relocatable;
+}
+
 /* The final scan for one insn, INSN.
    Args are same as in `final', except that INSN
    is the insn being scanned.
@@ -2493,7 +2509,8 @@ final_scan_insn_1 (rtx_insn *insn, FILE *file, int optimize_p ATTRIBUTE_UNUSED,
 	      int log_align;
 
 	      switch_to_section (targetm.asm_out.function_rodata_section
-				 (current_function_decl));
+				 (current_function_decl,
+				  jumptable_relocatable ()));
 
 #ifdef ADDR_VEC_ALIGN
 	      log_align = ADDR_VEC_ALIGN (table);
@@ -2572,7 +2589,8 @@ final_scan_insn_1 (rtx_insn *insn, FILE *file, int optimize_p ATTRIBUTE_UNUSED,
 
 	    if (! JUMP_TABLES_IN_TEXT_SECTION)
 	      switch_to_section (targetm.asm_out.function_rodata_section
-				 (current_function_decl));
+				 (current_function_decl,
+				  jumptable_relocatable ()));
 	    else
 	      switch_to_section (current_function_section ());