[PATCH v3] Enable tracing of pseudo-registers on ARM

[Antoine Tremblay <antoine.tremblay@ericsson.com>]

In this v3:
* Use gdbarch_remote_register_number to get the remote/tsec register number
Thanks to Pedro for pointing me in the right direction.
-

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/tfile-avx.c: Move to...
	* gdb.trace/tracefile-pseudo-reg.c: Here.
	* gdb.trace/tfile-avx.exp: Move to...
	* gdb.trace/tracefile-pseudo-reg.exp: Here.
---
 gdb/arm-tdep.c                                   | 71 ++++++++++++++++++
 gdb/testsuite/gdb.trace/tfile-avx.c              | 53 -------------
 gdb/testsuite/gdb.trace/tfile-avx.exp            | 73 ------------------
 gdb/testsuite/gdb.trace/tracefile-pseudo-reg.c   | 65 ++++++++++++++++
 gdb/testsuite/gdb.trace/tracefile-pseudo-reg.exp | 94 ++++++++++++++++++++++++
 5 files changed, 230 insertions(+), 126 deletions(-)
 delete mode 100644 gdb/testsuite/gdb.trace/tfile-avx.c
 delete mode 100644 gdb/testsuite/gdb.trace/tfile-avx.exp
 create mode 100644 gdb/testsuite/gdb.trace/tracefile-pseudo-reg.c
 create mode 100644 gdb/testsuite/gdb.trace/tracefile-pseudo-reg.exp

diff --git a/gdb/arm-tdep.c b/gdb/arm-tdep.c
index ccfefa8..1728de1 100644
--- a/gdb/arm-tdep.c
+++ b/gdb/arm-tdep.c
@@ -8718,6 +8718,73 @@ 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;
+
+  /* Get the remote/tdesc register number.  */
+  double_regnum = gdbarch_remote_register_number (gdbarch, double_regnum);
+
+  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)
 {
@@ -9379,6 +9446,10 @@ 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/tfile-avx.c b/gdb/testsuite/gdb.trace/tfile-avx.c
deleted file mode 100644
index 3cc3ec0..0000000
--- a/gdb/testsuite/gdb.trace/tfile-avx.c
+++ /dev/null
@@ -1,53 +0,0 @@
-/* This testcase is part of GDB, the GNU debugger.
-
-   Copyright 2016 Free Software Foundation, Inc.
-
-   This program is free software; you can redistribute it and/or modify
-   it under the terms of the GNU General Public License as published by
-   the Free Software Foundation; either version 3 of the License, or
-   (at your option) any later version.
-
-   This program is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-   GNU General Public License for more details.
-
-   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.
- */
-
-#include <immintrin.h>
-
-void
-dummy (void)
-{
-}
-
-static void
-end (void)
-{
-}
-
-int
-main (void)
-{
-  /* 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") = {
-    0x12340001,
-    0x12340002,
-    0x12340003,
-    0x12340004,
-    0x12340005,
-    0x12340006,
-    0x12340007,
-    0x12340008,
-  };
-  asm volatile ("traceme: call dummy" : : "x" (a));
-  end ();
-  return 0;
-}
diff --git a/gdb/testsuite/gdb.trace/tfile-avx.exp b/gdb/testsuite/gdb.trace/tfile-avx.exp
deleted file mode 100644
index 4c52c64..0000000
--- a/gdb/testsuite/gdb.trace/tfile-avx.exp
+++ /dev/null
@@ -1,73 +0,0 @@
-# Copyright 2016 Free Software Foundation, Inc.
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 3 of the License, or
-# (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# 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)."
-    return
-}
-
-load_lib "trace-support.exp"
-
-standard_testfile
-
-if {[prepare_for_testing $testfile.exp $testfile $srcfile \
-     [list debug additional_flags=-mavx]]} {
-    return -1
-}
-
-if ![runto_main] {
-    fail "Can't run to main to check for trace support"
-    return -1
-}
-
-if ![gdb_target_supports_trace] {
-    unsupported "target does not support trace"
-    return -1
-}
-
-gdb_test_multiple "print \$ymm15" "check for AVX support" {
-    -re " = void.*$gdb_prompt $" {
-	verbose "Skipping tfile AVX test (target doesn't support AVX)."
-	return
-    }
-    -re " = \\{.*}.*$gdb_prompt $" {
-	# All is well.
-    }
-}
-
-gdb_test "trace traceme" ".*"
-
-gdb_trace_setactions "set actions for tracepoint" "" \
-	"collect \$ymm15" "^$"
-
-gdb_breakpoint "end"
-
-gdb_test_no_output "tstart"
-
-gdb_test "continue" ".*Breakpoint $decimal, end .*"
-
-set tracefile [standard_output_file ${testfile}]
-
-# Save trace frames to tfile.
-gdb_test "tsave ${tracefile}.tf" \
-    "Trace data saved to file '${tracefile}.tf'.*" \
-    "save tfile trace file"
-
-# Change target to tfile.
-gdb_test "target tfile ${tracefile}.tf" "" "change to tfile target" \
-  "A program is being debugged already.  Kill it. .y or n. $" "y"
-
-gdb_test "tfind 0" "Found trace frame 0, tracepoint .*"
-
-gdb_test "print/x \$ymm15.v8_int32" " = \\{0x12340001, .*, 0x12340008}"
diff --git a/gdb/testsuite/gdb.trace/tracefile-pseudo-reg.c b/gdb/testsuite/gdb.trace/tracefile-pseudo-reg.c
new file mode 100644
index 0000000..473d805
--- /dev/null
+++ b/gdb/testsuite/gdb.trace/tracefile-pseudo-reg.c
@@ -0,0 +1,65 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2016 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   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.
+ */
+
+#if (defined __x86_64__)
+#include <immintrin.h>
+#elif (defined __arm__ || defined __thumb2__ || defined __thumb__)
+#include <arm_neon.h>
+#endif
+
+void
+dummy (void)
+{
+}
+
+static void
+end (void)
+{
+}
+
+int
+main (void)
+{
+  /* 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.  */
+#if (defined __x86_64__)
+  register __v8si a asm("xmm15") = {
+    0x12340001,
+    0x12340002,
+    0x12340003,
+    0x12340004,
+    0x12340005,
+    0x12340006,
+    0x12340007,
+    0x12340008,
+  };
+  asm volatile ("traceme: call dummy" : : "x" (a));
+#elif (defined __arm__ || defined __thumb2__ || defined __thumb__)
+  register uint32_t a asm("s5") = {
+    0x2
+  };
+  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
new file mode 100644
index 0000000..12a2740
--- /dev/null
+++ b/gdb/testsuite/gdb.trace/tracefile-pseudo-reg.exp
@@ -0,0 +1,94 @@
+# Copyright 2016 Free Software Foundation, Inc.
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# 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] && ! [istarget "arm*-*-*"] } {
+    verbose "Skipping tracefile pseudo register tests, target is not supported."
+    return
+}
+
+load_lib "trace-support.exp"
+
+standard_testfile
+
+if { [is_amd64_regs_target] } {
+ set add_flags "-mavx"
+} elseif { [istarget "arm*-*-*"] } {
+ set add_flags "-mfpu=neon"
+}
+
+if {[prepare_for_testing $testfile.exp $testfile $srcfile \
+     [list debug additional_flags=$add_flags]]} {
+    return -1
+}
+
+if ![runto_main] {
+    fail "Can't run to main to check for trace support"
+    return -1
+}
+
+if ![gdb_target_supports_trace] {
+    unsupported "target does not support trace"
+    return -1
+}
+
+if { [is_amd64_regs_target] } {
+    set reg "\$ymm15"
+    set reg_message "check for AVX support"
+} elseif { [istarget "arm*-*-*"] } {
+    set reg "\$s5"
+    set reg_message "check for Neon support"
+}
+
+gdb_test_multiple "print $reg" $reg_message {
+    -re " = void.*$gdb_prompt $" {
+	verbose "Skipping tracefile pseudo register tests, target is not supported."
+	return
+    }
+    -re " = \\{.*}.*$gdb_prompt $" {
+	# All is well.
+    }
+    -re " = 0.*$gdb_prompt $" {
+	# All is well.
+    }
+}
+
+gdb_test "trace traceme" ".*"
+
+gdb_trace_setactions "set actions for tracepoint" "" \
+	"collect $reg" "^$"
+
+gdb_breakpoint "end"
+
+gdb_test_no_output "tstart"
+
+gdb_test "continue" ".*Breakpoint $decimal, end .*"
+
+set tracefile [standard_output_file ${testfile}]
+
+# Save trace frames to tfile.
+gdb_test "tsave ${tracefile}.tf" \
+    "Trace data saved to file '${tracefile}.tf'.*" \
+    "save tfile trace file"
+
+# Change target to tfile.
+gdb_test "target tfile ${tracefile}.tf" "" "change to tfile target" \
+  "A program is being debugged already.  Kill it. .y or n. $" "y"
+
+gdb_test "tfind 0" "Found trace frame 0, tracepoint .*"
+
+if { [is_amd64_regs_target] } {
+    gdb_test "print/x \$ymm15.v8_int32" " = \\{0x12340001, .*, 0x12340008}"
+} elseif { [istarget "arm*-*-*"] } {
+    gdb_test "print \$s5" "2.80259693e-45"
+}
-- 
2.6.4