Re: [patch v4 06/13] linux, i386, amd64: enable btrace for 32bit and 64bit linux native

Pedro Alves
2012-11-28T18:40:02Z

On 11/27/2012 10:49 AM, markus.t.metzger@intel.com wrote:
> From: Markus Metzger <markus.t.metzger@intel.com>
>
> Install the btrace target ops for i386-linux-nat and amd64-linux-nat.
>
> 2012-11-27 Markus Metzger <markus.t.metzger@intel.com>
>
> * amd64-linux-nat.c: Include btrace.h and linux-btrace.h.
> (_initialize_amd64_linux_nat): Initialize btrace ops.
> * i386-linux.nat.c: Include btrace.h and linux-btrace.h.
> (_initialize_i386_linux_nat): Initialize btrace ops.
> * config/i386/linux.mh: Add linux-btrace.o.
> * config/i386/linux64.mh: Add linux-btrace.o.
>
>
> ---
> gdb/amd64-linux-nat.c | 51 ++++++++++++++++++++++++++++++++++++++++++++
> gdb/config/i386/linux.mh | 3 +-
> gdb/config/i386/linux64.mh | 2 +-
> gdb/i386-linux-nat.c | 51 ++++++++++++++++++++++++++++++++++++++++++++
> 4 files changed, 105 insertions(+), 2 deletions(-)
>
> diff --git a/gdb/amd64-linux-nat.c b/gdb/amd64-linux-nat.c
> index f4a12db..0e38a57 100644
> --- a/gdb/amd64-linux-nat.c
> +++ b/gdb/amd64-linux-nat.c
> @@ -25,6 +25,8 @@
> #include "regset.h"
> #include "linux-nat.h"
> #include "amd64-linux-tdep.h"
> +#include "linux-btrace.h"
> +#include "btrace.h"
>
> #include "gdb_assert.h"
> #include "gdb_string.h"
> @@ -1079,6 +1081,48 @@ amd64_linux_read_description (struct target_ops *ops)
> }
> }
>
> +/* Enable branch tracing for @ptid. */
> +static struct btrace_target_info *
> +amd64_linux_enable_btrace (ptid_t ptid)
> +{
> + struct btrace_target_info *tinfo;
> +
> + errno = 0;
> + tinfo = linux_enable_btrace (ptid);
> +
> + if (!tinfo)
> + error (_("Could not enable branch tracing for %s: %s."),
> + target_pid_to_str (ptid), safe_strerror (errno));
> +
> + return tinfo;
> +}
> +
> +/* Disable branch tracing for @ptid. */
> +static void
> +amd64_linux_disable_btrace (struct btrace_target_info *tinfo)
> +{
> + int errcode = linux_disable_btrace (tinfo);
> +
> + if (errcode)
> + error (_("Could not disable branch tracing: %s."), safe_strerror (errcode));
> +}
> +
> +/* Read branch trace data for @tinfo. */
> +static VEC (btrace_block_s) *
> +amd64_linux_read_btrace (struct btrace_target_info *tinfo)
> +{
> + /* Fill in the number of bits in a pointer for this architecture. */
> + if (!tinfo->ptr_bits)
> + {
> + struct gdbarch *gdbarch = target_gdbarch ();
> +
> + if (gdbarch)

You shouldn't ever see a NULL here.

> + tinfo->ptr_bits = gdbarch_ptr_bit (gdbarch);

It seems like this is something that should always be able
to compute on demand, without needing to store it once
per thread. This seems to have the same issue I pointed out
in a previous patch, with assuming TINFO is the same thread
as the current thread/inferior, and therefore that
target_gdbarch is appropriate for TINFO.

> + }
> +
> + return linux_read_btrace (tinfo);
> +}
> +
> /* Provide a prototype to silence -Wmissing-prototypes. */
> void _initialize_amd64_linux_nat (void);
>
> @@ -1117,6 +1161,13 @@ _initialize_amd64_linux_nat (void)
>
> t->to_read_description = amd64_linux_read_description;
>
> + /* Add btrace methods. */
> + t->to_supports_btrace = linux_supports_btrace;
> + t->to_enable_btrace = amd64_linux_enable_btrace;
> + t->to_disable_btrace = amd64_linux_disable_btrace;
> + t->to_btrace_has_changed = linux_btrace_has_changed;
> + t->to_read_btrace = amd64_linux_read_btrace;
> +
> /* Register the target. */
> linux_nat_add_target (t);
> linux_nat_set_new_thread (t, amd64_linux_new_thread);
> diff --git a/gdb/config/i386/linux.mh b/gdb/config/i386/linux.mh
> index 8316d87..7c64e83 100644
> --- a/gdb/config/i386/linux.mh
> +++ b/gdb/config/i386/linux.mh
> @@ -4,7 +4,8 @@ NAT_FILE= config/nm-linux.h
> NATDEPFILES= inf-ptrace.o fork-child.o \
> i386-nat.o i386-linux-nat.o \
> proc-service.o linux-thread-db.o \
> - linux-nat.o linux-osdata.o linux-fork.o linux-procfs.o linux-ptrace.o
> + linux-nat.o linux-osdata.o linux-fork.o linux-procfs.o linux-ptrace.o \
> + linux-btrace.o
> NAT_CDEPS = $(srcdir)/proc-service.list
>
> # The dynamically loaded libthread_db needs access to symbols in the
> diff --git a/gdb/config/i386/linux64.mh b/gdb/config/i386/linux64.mh
> index d2b95fd..8d782c1 100644
> --- a/gdb/config/i386/linux64.mh
> +++ b/gdb/config/i386/linux64.mh
> @@ -3,7 +3,7 @@ NATDEPFILES= inf-ptrace.o fork-child.o \
> i386-nat.o amd64-nat.o amd64-linux-nat.o \
> linux-nat.o linux-osdata.o \
> proc-service.o linux-thread-db.o linux-fork.o \
> - linux-procfs.o linux-ptrace.o
> + linux-procfs.o linux-ptrace.o linux-btrace.o
> NAT_FILE= config/nm-linux.h
> NAT_CDEPS = $(srcdir)/proc-service.list
>
> diff --git a/gdb/i386-linux-nat.c b/gdb/i386-linux-nat.c
> index 5a65ef6..c12d94a 100644
> --- a/gdb/i386-linux-nat.c
> +++ b/gdb/i386-linux-nat.c
> @@ -25,6 +25,8 @@
> #include "regset.h"
> #include "target.h"
> #include "linux-nat.h"
> +#include "linux-btrace.h"
> +#include "btrace.h"
>
> #include "gdb_assert.h"
> #include "gdb_string.h"
> @@ -1008,6 +1010,48 @@ i386_linux_read_description (struct target_ops *ops)
> return tdesc_i386_linux;
> }
>
> +/* Enable branch tracing for @ptid. */
> +static struct btrace_target_info *
> +i386_linux_enable_btrace (ptid_t ptid)
> +{
> + struct btrace_target_info *tinfo;
> +
> + errno = 0;
> + tinfo = linux_enable_btrace (ptid);
> +
> + if (!tinfo)
> + error (_("Could not enable branch tracing for %s: %s."),
> + target_pid_to_str (ptid), safe_strerror (errno));
> +
> + return tinfo;
> +}
> +
> +/* Disable branch tracing for @ptid. */
> +static void
> +i386_linux_disable_btrace (struct btrace_target_info *tinfo)
> +{
> + int errcode = linux_disable_btrace (tinfo);
> +
> + if (errcode)
> + error (_("Could not disable branch tracing: %s."), safe_strerror (errcode));
> +}
> +
> +/* Read branch trace data for @tinfo. */
> +static VEC (btrace_block_s) *
> +i386_linux_read_btrace (struct btrace_target_info *tinfo)
> +{
> + /* Fill in the number of bits in a pointer for this architecture. */
> + if (!tinfo->ptr_bits)
> + {
> + struct gdbarch *gdbarch = target_gdbarch ();
> +
> + if (gdbarch)
> + tinfo->ptr_bits = gdbarch_ptr_bit (gdbarch);
> + }
> +
> + return linux_read_btrace (tinfo);
> +}
> +
> /* -Wmissing-prototypes */
> extern initialize_file_ftype _initialize_i386_linux_nat;
>
> @@ -1041,6 +1085,13 @@ _initialize_i386_linux_nat (void)
>
> t->to_read_description = i386_linux_read_description;
>
> + /* Add btrace methods. */
> + t->to_supports_btrace = linux_supports_btrace;
> + t->to_enable_btrace = i386_linux_enable_btrace;
> + t->to_disable_btrace = i386_linux_disable_btrace;
> + t->to_btrace_has_changed = linux_btrace_has_changed;
> + t->to_read_btrace = i386_linux_read_btrace;
> +
> /* Register the target. */
> linux_nat_add_target (t);
> linux_nat_set_new_thread (t, i386_linux_new_thread);
> -- 1.7.1

--
Pedro Alves