[PATCH 04/10] Class readonly_detached_regcache

Yao Qi
2018-02-07T10:33:12Z

This patch adds a new class (type) for readonly regcache, which is
created via regcache::save. readonly_detached_regcache inherits
readable_regcache.

gdb:

2017-11-28 Yao Qi <yao.qi@linaro.org>

* dummy-frame.c (dummy_frame_cache) <prev_regcache>: Use
readonly_detached_regcache.
(dummy_frame_prev_register): Use regcache->cooked_read.
* frame.c (frame_save_as_regcache): Change return type.
(frame_pop): Update.
* frame.h (frame_save_as_regcache): Update declaration.
* inferior.h (get_infcall_suspend_state_regcache): Update
declaration.
* infrun.c (infcall_suspend_state) <registers>: use
readonly_detached_regcache.
(save_infcall_suspend_state): Don't use regcache_dup.
(get_infcall_suspend_state_regcache): Change return type.
* linux-fork.c (struct fork_info) <savedregs>: Change to
readonly_detached_regcache.
<pc>: New field.
(fork_save_infrun_state): Don't use regcache_dup.
(info_checkpoints_command): Adjust.
* mi/mi-main.c (register_changed_p): Update declaration.
(mi_cmd_data_list_changed_registers): Use
readonly_detached_regcache.
(register_changed_p): Change parameter type to
readonly_detached_regcache.
* ppc-linux-tdep.c (ppu2spu_cache) <regcache>: Use
readonly_detached_regcache.
(ppu2spu_sniffer): Construct a new readonly_detached_regcache.
* regcache.c (readonly_detached_regcache::readonly_detached_regcache):
New.
(regcache::save): Move it to reg_buffer.
(regcache::restore): Change parameter type.
(regcache_dup): Remove.
* regcache.h (reg_buffer) <save>: New method.
(readonly_detached_regcache): New class.
* spu-tdep.c (spu2ppu_cache) <regcache>: Use
readonly_detached_regcache.
(spu2ppu_sniffer): Construct a new readonly_detached_regcache.
---
gdb/dummy-frame.c | 6 +++---
gdb/frame.c | 10 +++++-----
gdb/frame.h | 3 ++-
gdb/inferior.h | 2 +-
gdb/infrun.c | 6 +++---
gdb/linux-fork.c | 18 ++++++++----------
gdb/mi/mi-main.c | 12 ++++++------
gdb/ppc-linux-tdep.c | 10 +++++-----
gdb/regcache.c | 27 +++++++++++----------------
gdb/regcache.h | 43 +++++++++++++++++++++++++++++++++----------
gdb/spu-tdep.c | 6 +++---
11 files changed, 80 insertions(+), 63 deletions(-)

diff --git a/gdb/dummy-frame.c b/gdb/dummy-frame.c
index db8ba1b..a67033e 100644
--- a/gdb/dummy-frame.c
+++ b/gdb/dummy-frame.c
@@ -282,7 +282,7 @@ cleanup_dummy_frames (struct target_ops *target, int from_tty)
struct dummy_frame_cache
{
struct frame_id this_id;
- struct regcache *prev_regcache;
+ readonly_detached_regcache *prev_regcache;
};

static int
@@ -352,8 +352,8 @@ dummy_frame_prev_register (struct frame_info *this_frame,
/* Use the regcache_cooked_read() method so that it, on the fly,
constructs either a raw or pseudo register from the raw
register cache. */
- regcache_cooked_read (cache->prev_regcache, regnum,
- value_contents_writeable (reg_val));
+ cache->prev_regcache->cooked_read (regnum,
+ value_contents_writeable (reg_val));
return reg_val;
}

diff --git a/gdb/frame.c b/gdb/frame.c
index 773fd04..0b04a4e 100644
--- a/gdb/frame.c
+++ b/gdb/frame.c
@@ -1017,13 +1017,13 @@ do_frame_register_read (void *src, int regnum, gdb_byte *buf)
return REG_VALID;
}

-std::unique_ptr<struct regcache>
+std::unique_ptr<readonly_detached_regcache>
frame_save_as_regcache (struct frame_info *this_frame)
{
- std::unique_ptr<struct regcache> regcache
- (new struct regcache (get_frame_arch (this_frame)));
+ std::unique_ptr<readonly_detached_regcache> regcache
+ (new readonly_detached_regcache (get_frame_arch (this_frame),
+ do_frame_register_read, this_frame));

- regcache->save (do_frame_register_read, this_frame);
return regcache;
}

@@ -1057,7 +1057,7 @@ frame_pop (struct frame_info *this_frame)
Save them in a scratch buffer so that there isn't a race between
trying to extract the old values from the current regcache while
at the same time writing new values into that same cache. */
- std::unique_ptr<struct regcache> scratch
+ std::unique_ptr<readonly_detached_regcache> scratch
= frame_save_as_regcache (prev_frame);

/* FIXME: cagney/2003-03-16: It should be possible to tell the
diff --git a/gdb/frame.h b/gdb/frame.h
index 8293a49..d5800b7 100644
--- a/gdb/frame.h
+++ b/gdb/frame.h
@@ -680,8 +680,9 @@ extern void *frame_obstack_zalloc (unsigned long size);
#define FRAME_OBSTACK_CALLOC(NUMBER,TYPE) \
((TYPE *) frame_obstack_zalloc ((NUMBER) * sizeof (TYPE)))

+class readonly_detached_regcache;
/* Create a regcache, and copy the frame's registers into it. */
-std::unique_ptr<struct regcache> frame_save_as_regcache
+std::unique_ptr<readonly_detached_regcache> frame_save_as_regcache
(struct frame_info *this_frame);

extern const struct block *get_frame_block (struct frame_info *,
diff --git a/gdb/inferior.h b/gdb/inferior.h
index 22008a0..391a5fd 100644
--- a/gdb/inferior.h
+++ b/gdb/inferior.h
@@ -70,7 +70,7 @@ extern struct cleanup *make_cleanup_restore_infcall_control_state
extern void discard_infcall_suspend_state (struct infcall_suspend_state *);
extern void discard_infcall_control_state (struct infcall_control_state *);

-extern struct regcache *
+extern readonly_detached_regcache *
get_infcall_suspend_state_regcache (struct infcall_suspend_state *);

extern void set_sigint_trap (void);
diff --git a/gdb/infrun.c b/gdb/infrun.c
index 742d130..92f668a 100644
--- a/gdb/infrun.c
+++ b/gdb/infrun.c
@@ -8809,7 +8809,7 @@ struct infcall_suspend_state

/* Other fields: */
CORE_ADDR stop_pc;
- struct regcache *registers;
+ readonly_detached_regcache *registers;

/* Format of SIGINFO_DATA or NULL if it is not present. */
struct gdbarch *siginfo_gdbarch;
@@ -8865,7 +8865,7 @@ save_infcall_suspend_state (void)

inf_state->stop_pc = stop_pc;

- inf_state->registers = regcache_dup (regcache);
+ inf_state->registers = new readonly_detached_regcache (*regcache);

return inf_state;
}
@@ -8922,7 +8922,7 @@ discard_infcall_suspend_state (struct infcall_suspend_state *inf_state)
xfree (inf_state);
}

-struct regcache *
+readonly_detached_regcache *
get_infcall_suspend_state_regcache (struct infcall_suspend_state *inf_state)
{
return inf_state->registers;
diff --git a/gdb/linux-fork.c b/gdb/linux-fork.c
index df7ea4e..9ffab1f 100644
--- a/gdb/linux-fork.c
+++ b/gdb/linux-fork.c
@@ -45,8 +45,9 @@ struct fork_info
ptid_t ptid;
ptid_t parent_ptid;
int num; /* Convenient handle (GDB fork id). */
- struct regcache *savedregs; /* Convenient for info fork, saves
+ readonly_detached_regcache *savedregs; /* Convenient for info fork, saves
having to actually switch contexts. */
+ CORE_ADDR pc;
int clobber_regs; /* True if we should restore saved regs. */
off_t *filepos; /* Set of open file descriptors' offsets. */
int maxfd;
@@ -294,7 +295,8 @@ fork_save_infrun_state (struct fork_info *fp, int clobber_regs)
if (fp->savedregs)
delete fp->savedregs;

- fp->savedregs = regcache_dup (get_current_regcache ());
+ fp->savedregs = new readonly_detached_regcache (*get_current_regcache ());
+ fp->pc = regcache_read_pc (get_current_regcache ());
fp->clobber_regs = clobber_regs;

if (clobber_regs)
@@ -590,15 +592,11 @@ info_checkpoints_command (const char *arg, int from_tty)

printed = fp;
if (ptid_equal (fp->ptid, inferior_ptid))
- {
- printf_filtered ("* ");
- pc = regcache_read_pc (get_current_regcache ());
- }
+ printf_filtered ("* ");
else
- {
- printf_filtered (" ");
- pc = regcache_read_pc (fp->savedregs);
- }
+ printf_filtered (" ");
+
+ pc = fp->pc;
printf_filtered ("%d %s", fp->num, target_pid_to_str (fp->ptid));
if (fp->num == 0)
printf_filtered (_(" (main process)"));
diff --git a/gdb/mi/mi-main.c b/gdb/mi/mi-main.c
index 51d33c9..1716a7f 100644
--- a/gdb/mi/mi-main.c
+++ b/gdb/mi/mi-main.c
@@ -96,8 +96,8 @@ static void mi_execute_cli_command (const char *cmd, int args_p,
const char *args);
static void mi_execute_async_cli_command (const char *cli_command,
char **argv, int argc);
-static bool register_changed_p (int regnum, regcache *,
- regcache *);
+static bool register_changed_p (int regnum, readonly_detached_regcache *,
+ readonly_detached_regcache *);
static void output_register (struct frame_info *, int regnum, int format,
int skip_unavailable);

@@ -931,9 +931,9 @@ mi_cmd_data_list_register_names (const char *command, char **argv, int argc)
void
mi_cmd_data_list_changed_registers (const char *command, char **argv, int argc)
{
- static std::unique_ptr<struct regcache> this_regs;
+ static std::unique_ptr<readonly_detached_regcache> this_regs;
struct ui_out *uiout = current_uiout;
- std::unique_ptr<struct regcache> prev_regs;
+ std::unique_ptr<readonly_detached_regcache> prev_regs;
struct gdbarch *gdbarch;
int regnum, numregs;
int i;
@@ -995,8 +995,8 @@ mi_cmd_data_list_changed_registers (const char *command, char **argv, int argc)
}

static bool
-register_changed_p (int regnum, struct regcache *prev_regs,
- struct regcache *this_regs)
+register_changed_p (int regnum, readonly_detached_regcache *prev_regs,
+ readonly_detached_regcache *this_regs)
{
struct gdbarch *gdbarch = this_regs->arch ();
struct value *prev_value, *this_value;
diff --git a/gdb/ppc-linux-tdep.c b/gdb/ppc-linux-tdep.c
index 13a50d6..d6a98fc 100644
--- a/gdb/ppc-linux-tdep.c
+++ b/gdb/ppc-linux-tdep.c
@@ -1262,7 +1262,7 @@ ppc_linux_spe_context (int wordsize, enum bfd_endian byte_order,
struct ppu2spu_cache
{
struct frame_id frame_id;
- struct regcache *regcache;
+ readonly_detached_regcache *regcache;
};

static struct gdbarch *
@@ -1369,10 +1369,10 @@ ppu2spu_sniffer (const struct frame_unwind *self,
{
struct ppu2spu_cache *cache
= FRAME_OBSTACK_CALLOC (1, struct ppu2spu_cache);
- std::unique_ptr<struct regcache> regcache
- (new struct regcache (data.gdbarch));
-
- regcache->save (ppu2spu_unwind_register, &data);
+ std::unique_ptr<readonly_detached_regcache> regcache
+ (new readonly_detached_regcache (data.gdbarch,
+ ppu2spu_unwind_register,
+ &data));

cache->frame_id = frame_id_build (base, func);
cache->regcache = regcache.release ();
diff --git a/gdb/regcache.c b/gdb/regcache.c
index 0df6a88..ebe3c7b 100644
--- a/gdb/regcache.c
+++ b/gdb/regcache.c
@@ -226,6 +226,11 @@ regcache::regcache (readonly_t, const regcache &src)
save (do_cooked_read, (void *) &src);
}

+readonly_detached_regcache::readonly_detached_regcache (const regcache &src)
+ : readonly_detached_regcache (src.arch (), do_cooked_read, (void *) &src)
+{
+}
+
gdbarch *
reg_buffer::arch () const
{
@@ -282,16 +287,14 @@ reg_buffer::register_buffer (int regnum) const
}

void
-regcache::save (regcache_cooked_read_ftype *cooked_read,
- void *src)
+reg_buffer::save (regcache_cooked_read_ftype *cooked_read,
+ void *src)
{
struct gdbarch *gdbarch = m_descr->gdbarch;
int regnum;

- /* The DST should be `read-only', if it wasn't then the save would
- end up trying to write the register values back out to the
- target. */
- gdb_assert (m_readonly_p);
+ /* It should have pseudo registers. */
+ gdb_assert (m_has_pseudo);
/* Clear the dest. */
memset (m_registers, 0, m_descr->sizeof_cooked_registers);
memset (m_register_status, 0, m_descr->nr_cooked_registers);
@@ -317,16 +320,14 @@ regcache::save (regcache_cooked_read_ftype *cooked_read,
}

void
-regcache::restore (struct regcache *src)
+regcache::restore (readonly_detached_regcache *src)
{
struct gdbarch *gdbarch = m_descr->gdbarch;
int regnum;

gdb_assert (src != NULL);
- /* The dst had better not be read-only. If it is, the `restore'
- doesn't make much sense. */
gdb_assert (!m_readonly_p);
- gdb_assert (src->m_readonly_p);
+ gdb_assert (src->m_has_pseudo);

gdb_assert (gdbarch == src->arch ());

@@ -344,12 +345,6 @@ regcache::restore (struct regcache *src)
}
}

-struct regcache *
-regcache_dup (struct regcache *src)
-{
- return new regcache (regcache::readonly, *src);
-}
-
enum register_status
regcache_register_status (const struct regcache *regcache, int regnum)
{
diff --git a/gdb/regcache.h b/gdb/regcache.h
index e1ab2e7..d4a9d9b 100644
--- a/gdb/regcache.h
+++ b/gdb/regcache.h
@@ -243,6 +243,11 @@ protected:

gdb_byte *register_buffer (int regnum) const;

+ /* Save a register cache. The set of registers saved into the
+ regcache determined by the save_reggroup. COOKED_READ returns
+ zero iff the register's value can't be returned. */
+ void save (regcache_cooked_read_ftype *cooked_read, void *src);
+
struct regcache_descr *m_descr;

bool m_has_pseudo;
@@ -250,6 +255,8 @@ protected:
gdb_byte *m_registers;
/* Register cache status. */
signed char *m_register_status;
+
+ friend class regcache;
};

/* An abstract class which only has methods doing read. */
@@ -284,6 +291,8 @@ protected:
bool is_raw);
};

+class readonly_detached_regcache;
+
/* The register cache for storing raw register values. */

class regcache : public readable_regcache
@@ -307,14 +316,11 @@ public:
return m_aspace;
}

-/* Save/restore a register cache. The set of registers saved /
- restored into the regcache determined by the save_reggroup /
- restore_reggroup respectively. COOKED_READ returns zero iff the
- register's value can't be returned. */
- void save (regcache_cooked_read_ftype *cooked_read, void *src);
- /* Writes to regcache will go through to the target. SRC is a
+ /* Restore a register cache. The set of registers restored into
+ the regcache determined by the restore_reggroup.
+ Writes to regcache will go through to the target. SRC is a
read-only register cache. */
- void restore (struct regcache *src);
+ void restore (readonly_detached_regcache *src);

void cooked_write (int regnum, const gdb_byte *buf);

@@ -412,9 +418,26 @@ private:
registers_changed_ptid (ptid_t ptid);
};

-/* Duplicate the contents of a register cache to a read-only register
- cache. The operation is pass-through. */
-extern struct regcache *regcache_dup (struct regcache *regcache);
+class readonly_detached_regcache : public readable_regcache
+{
+public:
+ readonly_detached_regcache (const regcache &src);
+
+ /* Create a readonly regcache by getting contents from COOKED_READ. */
+
+ readonly_detached_regcache (gdbarch *gdbarch,
+ regcache_cooked_read_ftype *cooked_read,
+ void *src)
+ : readable_regcache (gdbarch, true)
+ {
+ save (cooked_read, src);
+ }
+
+ DISABLE_COPY_AND_ASSIGN (readonly_detached_regcache);
+
+ void raw_update (int regnum) override
+ {}
+};

extern void registers_changed (void);
extern void registers_changed_ptid (ptid_t);
diff --git a/gdb/spu-tdep.c b/gdb/spu-tdep.c
index da7b937..a632c06 100644
--- a/gdb/spu-tdep.c
+++ b/gdb/spu-tdep.c
@@ -1202,7 +1202,7 @@ spu_write_pc (struct regcache *regcache, CORE_ADDR pc)
struct spu2ppu_cache
{
struct frame_id frame_id;
- struct regcache *regcache;
+ readonly_detached_regcache *regcache;
};

static struct gdbarch *
@@ -1229,7 +1229,7 @@ spu2ppu_prev_register (struct frame_info *this_frame,
gdb_byte *buf;

buf = (gdb_byte *) alloca (register_size (gdbarch, regnum));
- regcache_cooked_read (cache->regcache, regnum, buf);
+ cache->regcache->cooked_read (regnum, buf);
return frame_unwind_got_bytes (this_frame, regnum, buf);
}

@@ -1274,7 +1274,7 @@ spu2ppu_sniffer (const struct frame_unwind *self,
{
struct regcache *regcache;
regcache = get_thread_arch_regcache (inferior_ptid, target_gdbarch ());
- cache->regcache = regcache_dup (regcache);
+ cache->regcache = new readonly_detached_regcache (*regcache);
*this_prologue_cache = cache;
return 1;
}
--
1.9.1