ELF targets: avoid putting jump tables in .text section

Some systems (e.g. OpenBSD) can make the text section not readable.

Use .rodata section instead of .text.

Fixes: #508

Author: xavierleroy

powerpc/TargetPrinter.ml

@@ -130,7 +130,7 @@ module Linux_System : SYSTEM =
           elf_mergeable_string_section sz ".section	.rodata"
       | Section_literal sz ->
           elf_mergeable_literal_section sz ".section	.rodata"
-      | Section_jumptable -> ".text"
+      | Section_jumptable -> ".section	.rodata"
       | Section_user(s, wr, ex) ->
           sprintf ".section	\"%s\",\"a%s%s\",@progbits"
             s (if wr then "w" else "") (if ex then "x" else "")

x86/TargetPrinter.ml

@@ -152,7 +152,7 @@ module ELF_System : SYSTEM =
           elf_mergeable_string_section sz ".section	.rodata"
       | Section_literal sz ->
           elf_mergeable_literal_section sz ".section	.rodata"
-      | Section_jumptable -> ".text"
+      | Section_jumptable -> ".section	.rodata"
       | Section_user(s, wr, ex) ->
           sprintf ".section	\"%s\",\"a%s%s\",@progbits"
             s (if wr then "w" else "") (if ex then "x" else "")