[PATCH V2 2/5] Enable tracing of pseudo-registers on ARM

Antoine Tremblay
2016-11-03T14:33:29Z

This patch implements the ax_pseudo_register_push_stack and
ax_pseudo_register_collect gdbarch functions so that a pseudo-register can
be traced.

No regressions, tested on ubuntu 14.04 ARMv7 and x86.
With gdbserver-{native,extended} / { -marm -mthumb }

gdb/ChangeLog:

* arm-tdep.c (arm_pseudo_register_to_register): New function.
(arm_ax_pseudo_register_collect): New function.
(arm_ax_pseudo_register_push_stack): New function.
(arm_gdbarch_init): Set
gdbarch_ax_pseudo_register_{collect,push_stack} functions.

gdb/testsuite/ChangeLog:

* gdb.trace/tracefile-pseudo-reg.c: Include arm_neon.h if on arm.
(main): Add a register variable and a tracepoint label.
* gdb.trace/tracefile-pseudo-reg.exp: Add arm pseudo register
tracing test with s5 pseudo register.
---
gdb/arm-tdep.c | 68 ++++++++++++++++++++++++
gdb/testsuite/gdb.trace/tracefile-pseudo-reg.c | 16 ++++--
gdb/testsuite/gdb.trace/tracefile-pseudo-reg.exp | 35 +++++++++---
3 files changed, 108 insertions(+), 11 deletions(-)

diff --git a/gdb/arm-tdep.c b/gdb/arm-tdep.c
index 75343dd..6c00dac 100644
--- a/gdb/arm-tdep.c
+++ b/gdb/arm-tdep.c
@@ -8876,6 +8876,70 @@ arm_pseudo_write (struct gdbarch *gdbarch, struct regcache *regcache,
}
}

+/* Map the pseudo register number REG to the proper register number. */
+
+static int
+arm_pseudo_register_to_register (struct gdbarch *gdbarch, int reg)
+{
+ int double_regnum = 0;
+ int num_regs = gdbarch_num_regs (gdbarch);
+ char name_buf[4];
+
+ /* Single precision pseudo registers. s0-s31. */
+ if (reg >= num_regs && reg < num_regs + 32)
+ {
+ xsnprintf (name_buf, sizeof (name_buf), "d%d", (reg - num_regs) / 2);
+ double_regnum = user_reg_map_name_to_regnum (gdbarch, name_buf,
+ strlen (name_buf));
+ }
+ /* Quadruple precision pseudo regisers. q0-q15. */
+ else if (reg >= num_regs + 32 && reg < num_regs + 32 + 16)
+ {
+ xsnprintf (name_buf, sizeof (name_buf), "d%d", (reg - num_regs - 32) * 2);
+ double_regnum = user_reg_map_name_to_regnum (gdbarch, name_buf,
+ strlen (name_buf));
+ }
+ /* Error bad register number. */
+ else
+ return -1;
+
+ return double_regnum;
+}
+
+/* Implementation of the ax_pseudo_register_collect gdbarch function. */
+
+static int
+arm_ax_pseudo_register_collect (struct gdbarch *gdbarch,
+ struct agent_expr *ax, int reg)
+{
+ int rawnum = arm_pseudo_register_to_register (gdbarch, reg);
+
+ /* Error. */
+ if (rawnum < 0)
+ return 1;
+
+ ax_reg_mask (ax, rawnum);
+
+ return 0;
+}
+
+/* Implementation of the ax_pseudo_register_push_stack gdbarch function. */
+
+static int
+arm_ax_pseudo_register_push_stack (struct gdbarch *gdbarch,
+ struct agent_expr *ax, int reg)
+{
+ int rawnum = arm_pseudo_register_to_register (gdbarch, reg);
+
+ /* Error. */
+ if (rawnum < 0)
+ return 1;
+
+ ax_reg (ax, rawnum);
+
+ return 0;
+}
+
static struct value *
value_of_arm_user_reg (struct frame_info *frame, const void *baton)
{
@@ -9557,6 +9621,10 @@ arm_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
set_gdbarch_num_pseudo_regs (gdbarch, num_pseudos);
set_gdbarch_pseudo_register_read (gdbarch, arm_pseudo_read);
set_gdbarch_pseudo_register_write (gdbarch, arm_pseudo_write);
+ set_gdbarch_ax_pseudo_register_push_stack
+ (gdbarch, arm_ax_pseudo_register_push_stack);
+ set_gdbarch_ax_pseudo_register_collect
+ (gdbarch, arm_ax_pseudo_register_collect);
}

if (tdesc_data)
diff --git a/gdb/testsuite/gdb.trace/tracefile-pseudo-reg.c b/gdb/testsuite/gdb.trace/tracefile-pseudo-reg.c
index 3cc3ec0..1a751ee 100644
--- a/gdb/testsuite/gdb.trace/tracefile-pseudo-reg.c
+++ b/gdb/testsuite/gdb.trace/tracefile-pseudo-reg.c
@@ -15,12 +15,14 @@
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */

-/*
- * Test program for reading target description from tfile: collects AVX
- * registers on x86_64.
- */
+/* Test program for reading target description from tfile: collects pseudo
+ registers on the target. */

+#if (defined __x86_64__)
#include <immintrin.h>
+#elif (defined __arm__)
+#include <stdint.h>
+#endif

void
dummy (void)
@@ -35,6 +37,7 @@ end (void)
int
main (void)
{
+#if (defined __x86_64__)
/* Strictly speaking, it should be ymm15 (xmm15 is 128-bit), but gcc older
than 4.9 doesn't recognize "ymm15" as a valid register name. */
register __v8si a asm("xmm15") = {
@@ -48,6 +51,11 @@ main (void)
0x12340008,
};
asm volatile ("traceme: call dummy" : : "x" (a));
+#elif (defined __arm__)
+ register uint32_t a asm("s5") = 0x3f800000; /* 1. */
+ asm volatile ("traceme: bl dummy" : : "x" (a));
+#endif
+
end ();
return 0;
}
diff --git a/gdb/testsuite/gdb.trace/tracefile-pseudo-reg.exp b/gdb/testsuite/gdb.trace/tracefile-pseudo-reg.exp
index 4c52c64..6125c23 100644
--- a/gdb/testsuite/gdb.trace/tracefile-pseudo-reg.exp
+++ b/gdb/testsuite/gdb.trace/tracefile-pseudo-reg.exp
@@ -12,8 +12,8 @@
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.

-if { ! [is_amd64_regs_target] } {
- verbose "Skipping tfile AVX test (target is not x86_64)."
+if { ! [is_amd64_regs_target] && ! [istarget "arm*-*-*"] } {
+ verbose "Skipping tracefile pseudo register tests, target is not supported."
return
}

@@ -21,8 +21,14 @@ load_lib "trace-support.exp"

standard_testfile

+set add_flags ""
+
+if { [is_amd64_regs_target] } {
+ set add_flags "-mavx"
+}
+
if {[prepare_for_testing $testfile.exp $testfile $srcfile \
- [list debug additional_flags=-mavx]]} {
+ [list debug additional_flags=$add_flags]]} {
return -1
}

@@ -36,20 +42,31 @@ if ![gdb_target_supports_trace] {
return -1
}

-gdb_test_multiple "print \$ymm15" "check for AVX support" {
+if { [is_amd64_regs_target] } {
+ set reg "\$ymm15"
+} elseif { [istarget "arm*-*-*"] } {
+ set reg "\$s5"
+}
+
+set reg_message "check for register $reg"
+
+gdb_test_multiple "print $reg" $reg_message {
-re " = void.*$gdb_prompt $" {
- verbose "Skipping tfile AVX test (target doesn't support AVX)."
+ verbose "Skipping tracefile pseudo register tests, target is not supported."
return
}
-re " = \\{.*}.*$gdb_prompt $" {
# All is well.
}
+ -re " = 0.*$gdb_prompt $" {
+ # All is well.
+ }
}

gdb_test "trace traceme" ".*"

gdb_trace_setactions "set actions for tracepoint" "" \
- "collect \$ymm15" "^$"
+ "collect $reg" "^$"

gdb_breakpoint "end"

@@ -70,4 +87,8 @@ gdb_test "target tfile ${tracefile}.tf" "" "change to tfile target" \

gdb_test "tfind 0" "Found trace frame 0, tracepoint .*"

-gdb_test "print/x \$ymm15.v8_int32" " = \\{0x12340001, .*, 0x12340008}"
+if { [is_amd64_regs_target] } {
+ gdb_test "print/x \$ymm15.v8_int32" " = \\{0x12340001, .*, 0x12340008}"
+} elseif { [istarget "arm*-*-*"] } {
+ gdb_test "print \$s5" "1"
+}
--
2.9.2