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[PATCH v2] gdb.trace: Fix string collection for 64-bit platforms.
- From: Marcin KoÅcielnicki <koriakin at 0x04 dot net>
- To: palves at redhat dot com
- Cc: gdb-patches at sourceware dot org, Marcin KoÅcielnicki <koriakin at 0x04 dot net>
- Date: Thu, 21 Jan 2016 17:43:11 +0100
- Subject: [PATCH v2] gdb.trace: Fix string collection for 64-bit platforms.
- Authentication-results: sourceware.org; auth=none
- References: <56A103D5 dot 2090505 at redhat dot com>
String collection always used ref32 to fetch the string pointer. Make it
use gen_fetch instead.
As a side effect, this patch changes dup+const+trace+pop sequence used
for collecting the string's address to a trace_quick opcode. This
results in a shorter agent expression.
This appeared to work on x86_64 since it's a little-endian platform, and
malloc (used in gdb.trace/collection.exp) returns addresses in low 4GB.
Noticed and tested on s390x-ibm-linux-gnu, also tested on
i686-unknown-linux-gnu and x86_64-unknown-linux-gnu.
gdb/ChangeLog:
* ax-gdb.c (gen_traced_pop): Use gen_fetch for string collection.
---
Instead of factoring out the switch, I just delegated to gen_fetch.
Turns out we can shave off a few ops this way, too. Likewise tested
on s390, s390x, i686, x86_64.
gdb/ChangeLog | 4 ++++
gdb/ax-gdb.c | 23 +++++++++++------------
2 files changed, 15 insertions(+), 12 deletions(-)
diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 45d8ef9..28173b0 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,7 @@
+2016-01-21 Marcin KoÅcielnicki <koriakin@0x04.net>
+
+ * ax-gdb.c (gen_traced_pop): Use gen_fetch for string collection.
+
2016-01-21 Andrew Burgess <andrew.burgess@embecosm.com>
* disasm.c (maybe_add_dis_line_entry): Rename to...
diff --git a/gdb/ax-gdb.c b/gdb/ax-gdb.c
index dd6eee6..7c6cb64 100644
--- a/gdb/ax-gdb.c
+++ b/gdb/ax-gdb.c
@@ -394,26 +394,25 @@ gen_traced_pop (struct gdbarch *gdbarch,
case axs_lvalue_memory:
{
- if (string_trace)
- ax_simple (ax, aop_dup);
-
/* Initialize the TYPE_LENGTH if it is a typedef. */
check_typedef (value->type);
- /* There's no point in trying to use a trace_quick bytecode
- here, since "trace_quick SIZE pop" is three bytes, whereas
- "const8 SIZE trace" is also three bytes, does the same
- thing, and the simplest code which generates that will also
- work correctly for objects with large sizes. */
- ax_const_l (ax, TYPE_LENGTH (value->type));
- ax_simple (ax, aop_trace);
-
if (string_trace)
{
- ax_simple (ax, aop_ref32);
+ gen_fetch (ax, value->type);
ax_const_l (ax, ax->trace_string);
ax_simple (ax, aop_tracenz);
}
+ else
+ {
+ /* There's no point in trying to use a trace_quick bytecode
+ here, since "trace_quick SIZE pop" is three bytes, whereas
+ "const8 SIZE trace" is also three bytes, does the same
+ thing, and the simplest code which generates that will also
+ work correctly for objects with large sizes. */
+ ax_const_l (ax, TYPE_LENGTH (value->type));
+ ax_simple (ax, aop_trace);
+ }
}
break;
--
2.7.0