[PATCH 02/24] gdb: use reg_buffer_common throughout gdbsupport/common-regcache.h

Simon Marchi
2023-11-08T05:13:22Z

From: Simon Marchi <simon.marchi@efficios.com>

Right now, gdbsupport/common-regcache.h contains two abstractons for a
regcache. An opaque type `regcache` (gdb and gdbserver both have their
own regcache that is the concrete version of this) and an abstract base
class `reg_buffer_common`, that is the base of regcaches on both sides.
These abstractions allow code to be written for both gdb and gdbserver,
for instance in the gdb/arch sub-directory.

However, having two
different abstractions is impractical. If some common code has a regcache,
and wants to use an operation defined on reg_buffer_common, it can't.
It would be better to have just one. Change all instances of `regcache
*` in gdbsupport/common-regcache.h to be `reg_buffer_common *`, then fix
fallouts.

Implementations in gdb and gdbserver now need to down-cast (using
gdb::checked_static_cast) from reg_buffer_common to their concrete
regcache type. Some of them could be avoided by changing free functions
(like regcache_register_size) to be virtual methods on
reg_buffer_common. I tried it, it seems to work, but I did not include
it in this series to avoid adding unnecessary changes.

Change-Id: Ia5503adb6b5509a0f4604bd2a68b4642cc5283fd
---
gdb/arch/arm-get-next-pcs.c | 6 +++---
gdb/arch/arm-get-next-pcs.h | 5 +++--
gdb/arch/arm.c | 2 +-
gdb/arch/arm.h | 4 ++--
gdb/arm-linux-tdep.c | 11 ++++++-----
gdb/arm-tdep.c | 5 +++--
gdb/nat/aarch64-hw-point.c | 3 +--
gdb/nat/linux-btrace.c | 3 +--
gdb/regcache.c | 17 ++++++++++-------
gdbserver/linux-arm-low.cc | 4 +++-
gdbserver/regcache.cc | 19 ++++++++++++-------
gdbsupport/common-regcache.cc | 2 +-
gdbsupport/common-regcache.h | 17 ++++++++++-------
13 files changed, 56 insertions(+), 42 deletions(-)

diff --git a/gdb/arch/arm-get-next-pcs.c b/gdb/arch/arm-get-next-pcs.c
index dcbb5a5e2e69..6b033993304b 100644
--- a/gdb/arch/arm-get-next-pcs.c
+++ b/gdb/arch/arm-get-next-pcs.c
@@ -32,7 +32,7 @@ arm_get_next_pcs_ctor (struct arm_get_next_pcs *self,
int byte_order,
int byte_order_for_code,
int has_thumb2_breakpoint,
- struct regcache *regcache)
+ reg_buffer_common *regcache)
{
self->ops = ops;
self->byte_order = byte_order;
@@ -273,7 +273,7 @@ thumb_get_next_pcs_raw (struct arm_get_next_pcs *self)
unsigned short inst1;
CORE_ADDR nextpc = pc + 2; /* Default is next instruction. */
ULONGEST status, itstate;
- struct regcache *regcache = self->regcache;
+ reg_buffer_common *regcache = self->regcache;
std::vector<CORE_ADDR> next_pcs;

nextpc = MAKE_THUMB_ADDR (nextpc);
@@ -653,7 +653,7 @@ arm_get_next_pcs_raw (struct arm_get_next_pcs *self)
unsigned long this_instr = 0;
unsigned long status;
CORE_ADDR nextpc;
- struct regcache *regcache = self->regcache;
+ reg_buffer_common *regcache = self->regcache;
CORE_ADDR pc = regcache_read_pc (self->regcache);
std::vector<CORE_ADDR> next_pcs;

diff --git a/gdb/arch/arm-get-next-pcs.h b/gdb/arch/arm-get-next-pcs.h
index e6bb8d832286..ec347f01b4fd 100644
--- a/gdb/arch/arm-get-next-pcs.h
+++ b/gdb/arch/arm-get-next-pcs.h
@@ -24,6 +24,7 @@

/* Forward declaration. */
struct arm_get_next_pcs;
+struct reg_buffer_common;

/* get_next_pcs operations. */
struct arm_get_next_pcs_ops
@@ -50,7 +51,7 @@ struct arm_get_next_pcs
not. */
int has_thumb2_breakpoint;
/* Registry cache. */
- struct regcache *regcache;
+ reg_buffer_common *regcache;
};

/* Initialize arm_get_next_pcs. */
@@ -59,7 +60,7 @@ void arm_get_next_pcs_ctor (struct arm_get_next_pcs *self,
int byte_order,
int byte_order_for_code,
int has_thumb2_breakpoint,
- struct regcache *regcache);
+ reg_buffer_common *regcache);

/* Find the next possible PCs after the current instruction executes. */
std::vector<CORE_ADDR> arm_get_next_pcs (struct arm_get_next_pcs *self);
diff --git a/gdb/arch/arm.c b/gdb/arch/arm.c
index 4720c201c532..88737fc357f8 100644
--- a/gdb/arch/arm.c
+++ b/gdb/arch/arm.c
@@ -322,7 +322,7 @@ thumb2_instruction_changes_pc (unsigned short inst1, unsigned short inst2)
/* See arm.h. */

unsigned long
-shifted_reg_val (struct regcache *regcache, unsigned long inst,
+shifted_reg_val (reg_buffer_common *regcache, unsigned long inst,
int carry, unsigned long pc_val, unsigned long status_reg)
{
unsigned long res, shift;
diff --git a/gdb/arch/arm.h b/gdb/arch/arm.h
index c64a15600de3..b6c316191877 100644
--- a/gdb/arch/arm.h
+++ b/gdb/arch/arm.h
@@ -188,7 +188,7 @@ enum system_register_address : CORE_ADDR
((CORE_ADDR) (((unsigned long) (addr)) + 8 + (sbits (instr, 0, 23) << 2)))

/* Forward declaration. */
-struct regcache;
+struct reg_buffer_common;

/* Return the size in bytes of the complete Thumb instruction whose
first halfword is INST1. */
@@ -213,7 +213,7 @@ int thumb_advance_itstate (unsigned int itstate);

/* Decode shifted register value. */

-unsigned long shifted_reg_val (struct regcache *regcache,
+unsigned long shifted_reg_val (reg_buffer_common *regcache,
unsigned long inst,
int carry,
unsigned long pc_val,
diff --git a/gdb/arm-linux-tdep.c b/gdb/arm-linux-tdep.c
index dfa816990ff5..909a20324fd5 100644
--- a/gdb/arm-linux-tdep.c
+++ b/gdb/arm-linux-tdep.c
@@ -869,8 +869,10 @@ static CORE_ADDR
arm_linux_get_next_pcs_syscall_next_pc (struct arm_get_next_pcs *self)
{
CORE_ADDR next_pc = 0;
- CORE_ADDR pc = regcache_read_pc (self->regcache);
- int is_thumb = arm_is_thumb (self->regcache);
+ regcache *regcache
+ = gdb::checked_static_cast<struct regcache *> (self->regcache);
+ CORE_ADDR pc = regcache_read_pc (regcache);
+ int is_thumb = arm_is_thumb (regcache);
ULONGEST svc_number = 0;

if (is_thumb)
@@ -880,7 +882,7 @@ arm_linux_get_next_pcs_syscall_next_pc (struct arm_get_next_pcs *self)
}
else
{
- struct gdbarch *gdbarch = self->regcache->arch ();
+ struct gdbarch *gdbarch = regcache->arch ();
enum bfd_endian byte_order_for_code =
gdbarch_byte_order_for_code (gdbarch);
unsigned long this_instr =
@@ -903,8 +905,7 @@ arm_linux_get_next_pcs_syscall_next_pc (struct arm_get_next_pcs *self)
{
/* SIGRETURN or RT_SIGRETURN may affect the arm thumb mode, so
update IS_THUMB. */
- next_pc = arm_linux_sigreturn_next_pc (self->regcache, svc_number,
- &is_thumb);
+ next_pc = arm_linux_sigreturn_next_pc (regcache, svc_number, &is_thumb);
}

/* Addresses for calling Thumb functions have the bit 0 set. */
diff --git a/gdb/arm-tdep.c b/gdb/arm-tdep.c
index d4047ddbb868..2018f4ed0edd 100644
--- a/gdb/arm-tdep.c
+++ b/gdb/arm-tdep.c
@@ -7255,7 +7255,8 @@ CORE_ADDR
arm_get_next_pcs_addr_bits_remove (struct arm_get_next_pcs *self,
CORE_ADDR val)
{
- return gdbarch_addr_bits_remove (self->regcache->arch (), val);
+ return gdbarch_addr_bits_remove
+ (gdb::checked_static_cast<regcache *> (self->regcache)->arch (), val);
}

/* Wrapper over syscall_next_pc for use in get_next_pcs. */
@@ -7271,7 +7272,7 @@ arm_get_next_pcs_syscall_next_pc (struct arm_get_next_pcs *self)
int
arm_get_next_pcs_is_thumb (struct arm_get_next_pcs *self)
{
- return arm_is_thumb (self->regcache);
+ return arm_is_thumb (gdb::checked_static_cast<regcache *> (self->regcache));
}

/* single_step() is called just before we want to resume the inferior,
diff --git a/gdb/nat/aarch64-hw-point.c b/gdb/nat/aarch64-hw-point.c
index 6747e61e0265..8e9a532cd2a4 100644
--- a/gdb/nat/aarch64-hw-point.c
+++ b/gdb/nat/aarch64-hw-point.c
@@ -137,8 +137,7 @@ aarch64_point_is_aligned (ptid_t ptid, int is_watchpoint, CORE_ADDR addr,
alignment = AARCH64_HWP_ALIGNMENT;
else
{
- struct regcache *regcache
- = get_thread_regcache_for_ptid (ptid);
+ reg_buffer_common *regcache = get_thread_regcache_for_ptid (ptid);

/* Set alignment to 2 only if the current process is 32-bit,
since thumb instruction can be 2-byte aligned. Otherwise, set
diff --git a/gdb/nat/linux-btrace.c b/gdb/nat/linux-btrace.c
index 3c217daa4886..7c4b40e40b8a 100644
--- a/gdb/nat/linux-btrace.c
+++ b/gdb/nat/linux-btrace.c
@@ -284,13 +284,12 @@ perf_event_read_bts (btrace_target_info *tinfo, const uint8_t *begin,
struct perf_event_sample sample;
size_t read = 0;
struct btrace_block block = { 0, 0 };
- struct regcache *regcache;

gdb_assert (begin <= start);
gdb_assert (start <= end);

/* The first block ends at the current pc. */
- regcache = get_thread_regcache_for_ptid (tinfo->ptid);
+ reg_buffer_common *regcache = get_thread_regcache_for_ptid (tinfo->ptid);
block.end = regcache_read_pc (regcache);

/* The buffer may contain a partial record as its last entry (i.e. when the
diff --git a/gdb/regcache.c b/gdb/regcache.c
index 2e48c0258091..11a6ecc3469e 100644
--- a/gdb/regcache.c
+++ b/gdb/regcache.c
@@ -180,9 +180,10 @@ register_size (struct gdbarch *gdbarch, int regnum)
/* See gdbsupport/common-regcache.h. */

int
-regcache_register_size (const struct regcache *regcache, int n)
+regcache_register_size (const reg_buffer_common *regcache, int n)
{
- return register_size (regcache->arch (), n);
+ return register_size
+ ( gdb::checked_static_cast<const struct regcache *> (regcache)->arch (), n);
}

reg_buffer::reg_buffer (gdbarch *gdbarch, bool has_pseudo)
@@ -435,7 +436,7 @@ get_current_regcache (void)

/* See gdbsupport/common-regcache.h. */

-struct regcache *
+reg_buffer_common *
get_thread_regcache_for_ptid (ptid_t ptid)
{
/* This function doesn't take a process_stratum_target parameter
@@ -648,11 +649,12 @@ readable_regcache::raw_read (int regnum, T *val)
}

enum register_status
-regcache_raw_read_unsigned (struct regcache *regcache, int regnum,
+regcache_raw_read_unsigned (reg_buffer_common *regcache, int regnum,
ULONGEST *val)
{
gdb_assert (regcache != NULL);
- return regcache->raw_read (regnum, val);
+ return gdb::checked_static_cast<struct regcache *> (regcache)->raw_read
+ (regnum, val);
}

void
@@ -1332,8 +1334,9 @@ reg_buffer::raw_compare (int regnum, const void *buf, int offset) const
/* Special handling for register PC. */

CORE_ADDR
-regcache_read_pc (struct regcache *regcache)
+regcache_read_pc (reg_buffer_common *reg_buf)
{
+ regcache *regcache = gdb::checked_static_cast<struct regcache *> (reg_buf);
struct gdbarch *gdbarch = regcache->arch ();

CORE_ADDR pc_val;
@@ -1360,7 +1363,7 @@ regcache_read_pc (struct regcache *regcache)
/* See gdbsupport/common-regcache.h. */

CORE_ADDR
-regcache_read_pc_protected (regcache *regcache)
+regcache_read_pc_protected (reg_buffer_common *regcache)
{
CORE_ADDR pc;
try
diff --git a/gdbserver/linux-arm-low.cc b/gdbserver/linux-arm-low.cc
index 5975b44af0ae..0a6f3622695a 100644
--- a/gdbserver/linux-arm-low.cc
+++ b/gdbserver/linux-arm-low.cc
@@ -24,6 +24,7 @@
#include "linux-aarch32-low.h"
#include "linux-aarch32-tdesc.h"
#include "linux-arm-tdesc.h"
+#include "gdbsupport/gdb-checked-static-cast.h"

#include <sys/uio.h>
/* Don't include elf.h if linux/elf.h got included by gdb_proc_service.h.
@@ -913,7 +914,8 @@ get_next_pcs_syscall_next_pc (struct arm_get_next_pcs *self)
CORE_ADDR pc = regcache_read_pc (self->regcache);
int is_thumb = arm_is_thumb_mode ();
ULONGEST svc_number = 0;
- struct regcache *regcache = self->regcache;
+ regcache *regcache
+ = gdb::checked_static_cast<struct regcache *> (self->regcache);

if (is_thumb)
{
diff --git a/gdbserver/regcache.cc b/gdbserver/regcache.cc
index 0b1141662ac6..4ac0fb659c3b 100644
--- a/gdbserver/regcache.cc
+++ b/gdbserver/regcache.cc
@@ -21,6 +21,8 @@
#include "gdbthread.h"
#include "tdesc.h"
#include "gdbsupport/rsp-low.h"
+#include "gdbsupport/gdb-checked-static-cast.h"
+
#ifndef IN_PROCESS_AGENT

struct regcache *
@@ -64,7 +66,7 @@ get_thread_regcache (struct thread_info *thread, int fetch)

/* See gdbsupport/common-regcache.h. */

-struct regcache *
+reg_buffer_common *
get_thread_regcache_for_ptid (ptid_t ptid)
{
return get_thread_regcache (find_thread_ptid (ptid), 1);
@@ -307,9 +309,10 @@ register_size (const struct target_desc *tdesc, int n)
/* See gdbsupport/common-regcache.h. */

int
-regcache_register_size (const struct regcache *regcache, int n)
+regcache_register_size (const reg_buffer_common *regcache, int n)
{
- return register_size (regcache->tdesc, n);
+ return register_size
+ (gdb::checked_static_cast<const struct regcache *> (regcache)->tdesc, n);
}

static unsigned char *
@@ -437,13 +440,14 @@ regcache::raw_collect (int n, void *buf) const
}

enum register_status
-regcache_raw_read_unsigned (struct regcache *regcache, int regnum,
+regcache_raw_read_unsigned (reg_buffer_common *reg_buf, int regnum,
ULONGEST *val)
{
int size;
+ regcache *regcache = gdb::checked_static_cast<struct regcache *> (reg_buf);

gdb_assert (regcache != NULL);
-
+
size = register_size (regcache->tdesc, regnum);

if (size > (int) sizeof (ULONGEST))
@@ -486,9 +490,10 @@ collect_register_by_name (struct regcache *regcache,
/* Special handling for register PC. */

CORE_ADDR
-regcache_read_pc (struct regcache *regcache)
+regcache_read_pc (reg_buffer_common *regcache)
{
- return the_target->read_pc (regcache);
+ return the_target->read_pc
+ (gdb::checked_static_cast<struct regcache *> (regcache));
}

void
diff --git a/gdbsupport/common-regcache.cc b/gdbsupport/common-regcache.cc
index 3515bedb3830..b6f02bac16e2 100644
--- a/gdbsupport/common-regcache.cc
+++ b/gdbsupport/common-regcache.cc
@@ -23,7 +23,7 @@
/* Return the register's value or throw if it's not available. */

ULONGEST
-regcache_raw_get_unsigned (struct regcache *regcache, int regnum)
+regcache_raw_get_unsigned (reg_buffer_common *regcache, int regnum)
{
ULONGEST value;
enum register_status status;
diff --git a/gdbsupport/common-regcache.h b/gdbsupport/common-regcache.h
index e462f532407b..6d98ca8c92ed 100644
--- a/gdbsupport/common-regcache.h
+++ b/gdbsupport/common-regcache.h
@@ -20,6 +20,8 @@
#ifndef COMMON_COMMON_REGCACHE_H
#define COMMON_COMMON_REGCACHE_H

+struct reg_buffer_common;
+
/* This header is a stopgap until we have an independent regcache. */

enum register_status : signed char
@@ -44,28 +46,29 @@ enum register_status : signed char
thread specified by PTID. This function must be provided by
the client. */

-extern struct regcache *get_thread_regcache_for_ptid (ptid_t ptid);
+extern reg_buffer_common *get_thread_regcache_for_ptid (ptid_t ptid);

/* Return the size of register numbered N in REGCACHE. This function
must be provided by the client. */

-extern int regcache_register_size (const struct regcache *regcache, int n);
+extern int regcache_register_size (const reg_buffer_common *regcache, int n);

/* Read the PC register. This function must be provided by the
client. */

-extern CORE_ADDR regcache_read_pc (struct regcache *regcache);
+extern CORE_ADDR regcache_read_pc (reg_buffer_common *regcache);

/* Read the PC register. If PC cannot be read, return 0.
This is a wrapper around 'regcache_read_pc'. */

-extern CORE_ADDR regcache_read_pc_protected (regcache *regcache);
+extern CORE_ADDR regcache_read_pc_protected (reg_buffer_common *regcache);

/* Read a raw register into a unsigned integer. */
-extern enum register_status regcache_raw_read_unsigned
- (struct regcache *regcache, int regnum, ULONGEST *val);
+extern enum register_status
+regcache_raw_read_unsigned (reg_buffer_common *regcache, int regnum,
+ ULONGEST *val);

-ULONGEST regcache_raw_get_unsigned (struct regcache *regcache, int regnum);
+ULONGEST regcache_raw_get_unsigned (reg_buffer_common *regcache, int regnum);

struct reg_buffer_common
{
--
2.42.1