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[patch] Fix DW_OP_call2 and DW_OP_call4 for max-cache-age 0
- From: Jan Kratochvil <jan dot kratochvil at redhat dot com>
- To: gdb-patches at sourceware dot org
- Date: Mon, 23 Aug 2010 20:50:08 +0200
- Subject: [patch] Fix DW_OP_call2 and DW_OP_call4 for max-cache-age 0
Hi,
as discussed on #gdb when you set max-cache-age 0 DW_OP_call{2,4} crashed GDB.
I admit I rather did not test max-cache-age 0 globally.
No regressions on {x86_64,x86_64-m32,i686}-fedora14snapshot-linux-gnu.
OK to check-in?
The problem is not reproducible with max-cache-age 1. Without the
dw2_do_instantiate_symtab patch part GDB no longer crashes on max-cache-age 0
but it will then error out on DW_OP_call{2,4} with that:
+ error (_("Dwarf Error: Cannot read CU for DIE at 0x%x referenced "
+ "in module %s"),
There is a bit weird that functions with parameter per_cu have also parameter
objfile when there is per_cu->objfile. It is because per_cu->objfile is there
only since cf9fe5cf2be8b76820a05c966cdca6df5c2eee24 (Tom Tromey 2010-07-13).
Thanks,
Jan
gdb/
2010-08-23 Jan Kratochvil <jan.kratochvil@redhat.com>
* dwarf2read.c (dw2_do_instantiate_symtab): Move the
age_cached_comp_units call to the top, extend its comment.
(dwarf2_fetch_die_location_block): Initialize cu later. Call
dw2_setup and dw2_do_instantiate_symtab if PER_CU->CU is NULL.
gdb/testsuite/
2010-08-23 Jan Kratochvil <jan.kratochvil@redhat.com>
* gdb.dwarf2/dw2-op-call.exp (maintenance set dwarf2 max-cache-age 0):
New test.
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -1636,6 +1636,11 @@ dw2_do_instantiate_symtab (struct objfile *objfile,
{
struct cleanup *back_to;
+ /* Age the cache, releasing compilation units that have not been used
+ recently. Age them first so that we do not age out the requested PER_CU
+ unit if DWARF2_MAX_CACHE_AGE is too low. */
+ age_cached_comp_units ();
+
back_to = make_cleanup (dwarf2_release_queue, NULL);
queue_comp_unit (per_cu, objfile);
@@ -1647,10 +1652,6 @@ dw2_do_instantiate_symtab (struct objfile *objfile,
process_queue (objfile);
- /* Age the cache, releasing compilation units that have not
- been used recently. */
- age_cached_comp_units ();
-
do_cleanups (back_to);
}
@@ -12720,11 +12721,22 @@ struct dwarf2_locexpr_baton
dwarf2_fetch_die_location_block (unsigned int offset,
struct dwarf2_per_cu_data *per_cu)
{
- struct dwarf2_cu *cu = per_cu->cu;
+ struct dwarf2_cu *cu;
struct die_info *die;
struct attribute *attr;
struct dwarf2_locexpr_baton retval;
+ if (per_cu->cu == NULL)
+ {
+ dw2_setup (per_cu->objfile);
+ dw2_do_instantiate_symtab (per_cu->objfile, per_cu);
+ }
+ if (per_cu->cu == NULL)
+ error (_("Dwarf Error: Cannot read CU for DIE at 0x%x referenced "
+ "in module %s"),
+ offset, per_cu->objfile->name);
+
+ cu = per_cu->cu;
die = follow_die_offset (offset, &cu);
if (!die)
error (_("Dwarf Error: Cannot find DIE at 0x%x referenced in module %s"),
--- a/gdb/testsuite/gdb.dwarf2/dw2-op-call.exp
+++ b/gdb/testsuite/gdb.dwarf2/dw2-op-call.exp
@@ -36,6 +36,9 @@ if { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${objdir}/${subdir}/${execu
clean_restart $executable
+# Additional test to verify the referenced CU is not aged out.
+gdb_test_no_output "maintenance set dwarf2 max-cache-age 0"
+
gdb_test "p array1" " = 1"
gdb_test "p array2" " = 2" "array2 using DW_OP_call2"
gdb_test "p array3" " = 3" "array3 using DW_OP_call4"