compile: Use also inferior munmap

Currently inferior memory is allocated by inferior mmap() but it is never
deallocated; despite the injected objfile incl. its symbols is freed.  This was
intentional so that one can do for example:
inferior:
	char *str = "foo";
GDB:
	(gdb) compile code str = "bar";

I believe later patches will be needed to introduce full control over keeping
vs. discarding the injected module as being discussed in:
	compile: objfiles lifetime UI
	https://sourceware.org/ml/gdb/2015-04/msg00051.html
	Message-ID: <20150429135735.GA16974@host1.jankratochvil.net>
	https://sourceware.org/ml/gdb/2015-05/msg00007.html

As decided by Phil it is better not to leak inferior pages as users can
workaround the issue above for example by:
	(gdb) compile code str = strdup ("bar");

I have checked that in fact gdb/doc/ (written by Phil) already expects the
injected code will be unmapped so that does not need to be changed:
	compile code int ff = 5; p = &ff;
	In this example, @code{p} would point to @code{ff} when the
	@code{compile} command is executing the source code provided to it.
	However, as variables in the (example) program persist with their
	assigned values, the variable @code{p} would point to an invalid
	location when the command exists.

gdb/ChangeLog
2015-04-28  Jan Kratochvil  <jan.kratochvil@redhat.com>

	* arch-utils.c (default_infcall_munmap): New.
	* arch-utils.h (default_infcall_munmap): New declaration.
	* compile/compile-object-load.c (struct munmap_list, munmap_list_add)
	(munmap_list_free, munmap_listp_free_cleanup): New.
	(struct setup_sections_data): Add field munmap_list_headp.
	(setup_sections): Call munmap_list_add.
	(compile_object_load): New variable munmap_list_head, initialize
	setup_sections_data.munmap_list_headp, return munmap_list_head.
	* compile/compile-object-load.h (struct munmap_list): New declaration.
	(struct compile_module): Add field munmap_list_head.
	(munmap_list_free): New declaration.
	* compile/compile-object-run.c (struct do_module_cleanup): Add field
	munmap_list_head.
	(do_module_cleanup): Call munmap_list_free.
	(compile_object_run): Pass munmap_list_head to do_module_cleanup.
	* gdbarch.c: Regenerate.
	* gdbarch.h: Regenerate.
	* gdbarch.sh (infcall_munmap): New.
	* linux-tdep.c (linux_infcall_munmap): New.
	(linux_init_abi): Install it.

gdb/testsuite/ChangeLog
2015-04-28  Jan Kratochvil  <jan.kratochvil@redhat.com>

	* gdb.compile/compile.exp (keep jit in memory): Rename to ...
	(do not keep jit in memory): ... this.
	(expect 5): Change it to ...
	(expect no 5): ... this.

1 files changed, 23 insertions, 0 deletions

diff --git a/gdb/gdbarch.c b/gdb/gdbarch.c
index 821ad5e..ebff510 100644
--- a/gdb/gdbarch.c
+++ b/gdb/gdbarch.c
@@ -326,6 +326,7 @@ struct gdbarch
   gdbarch_auxv_parse_ftype *auxv_parse;
   gdbarch_vsyscall_range_ftype *vsyscall_range;
   gdbarch_infcall_mmap_ftype *infcall_mmap;
+  gdbarch_infcall_munmap_ftype *infcall_munmap;
   gdbarch_gcc_target_options_ftype *gcc_target_options;
   gdbarch_gnu_triplet_regexp_ftype *gnu_triplet_regexp;
 };
@@ -426,6 +427,7 @@ gdbarch_alloc (const struct gdbarch_info *info,
   gdbarch->insn_is_jump = default_insn_is_jump;
   gdbarch->vsyscall_range = default_vsyscall_range;
   gdbarch->infcall_mmap = default_infcall_mmap;
+  gdbarch->infcall_munmap = default_infcall_munmap;
   gdbarch->gcc_target_options = default_gcc_target_options;
   gdbarch->gnu_triplet_regexp = default_gnu_triplet_regexp;
   /* gdbarch_alloc() */
@@ -658,6 +660,7 @@ verify_gdbarch (struct gdbarch *gdbarch)
   /* Skip verify of auxv_parse, has predicate.  */
   /* Skip verify of vsyscall_range, invalid_p == 0 */
   /* Skip verify of infcall_mmap, invalid_p == 0 */
+  /* Skip verify of infcall_munmap, invalid_p == 0 */
   /* Skip verify of gcc_target_options, invalid_p == 0 */
   /* Skip verify of gnu_triplet_regexp, invalid_p == 0 */
   buf = ui_file_xstrdup (log, &length);
@@ -1029,6 +1032,9 @@ gdbarch_dump (struct gdbarch *gdbarch, struct ui_file *file)
                       "gdbarch_dump: infcall_mmap = <%s>\n",
                       host_address_to_string (gdbarch->infcall_mmap));
   fprintf_unfiltered (file,
+                      "gdbarch_dump: infcall_munmap = <%s>\n",
+                      host_address_to_string (gdbarch->infcall_munmap));
+  fprintf_unfiltered (file,
                       "gdbarch_dump: gdbarch_info_proc_p() = %d\n",
                       gdbarch_info_proc_p (gdbarch));
   fprintf_unfiltered (file,
@@ -4673,6 +4679,23 @@ set_gdbarch_infcall_mmap (struct gdbarch *gdbarch,
   gdbarch->infcall_mmap = infcall_mmap;
 }
 
+void
+gdbarch_infcall_munmap (struct gdbarch *gdbarch, CORE_ADDR addr, CORE_ADDR size)
+{
+  gdb_assert (gdbarch != NULL);
+  gdb_assert (gdbarch->infcall_munmap != NULL);
+  if (gdbarch_debug >= 2)
+    fprintf_unfiltered (gdb_stdlog, "gdbarch_infcall_munmap called\n");
+  gdbarch->infcall_munmap (addr, size);
+}
+
+void
+set_gdbarch_infcall_munmap (struct gdbarch *gdbarch,
+                            gdbarch_infcall_munmap_ftype infcall_munmap)
+{
+  gdbarch->infcall_munmap = infcall_munmap;
+}
+
 char *
 gdbarch_gcc_target_options (struct gdbarch *gdbarch)
 {