On 2018-06-21 05:38 AM, Alan Hayward wrote:
> Additionally, tidy up the functions: Remove asserts, use gdb_byte,
> update comments.
Thanks, that's a nice cleanup.
Just two nits, the patch LGTM with those fixed.
> diff --git a/gdb/regcache.c b/gdb/regcache.c
> index 6276b149a2..fe4742c2ee 100644
> --- a/gdb/regcache.c
> +++ b/gdb/regcache.c
> @@ -775,77 +775,75 @@ regcache::cooked_write (int regnum, const gdb_byte *buf)
> regnum, buf);
> }
>
> -/* Perform a partial register transfer using a read, modify, write
> - operation. */
> +/* See regcache.h. */
>
> enum register_status
> -readable_regcache::read_part (int regnum, int offset, int len, void *in,
> - bool is_raw)
> +readable_regcache::read_part (int regnum, int offset, int len,
> + gdb_byte *out, bool is_raw)
> {
> - struct gdbarch *gdbarch = arch ();
> - gdb_byte *reg = (gdb_byte *) alloca (register_size (gdbarch, regnum));
> + int reg_size = register_size (arch (), regnum);
>
> - gdb_assert (in != NULL);
> - gdb_assert (offset >= 0 && offset <= m_descr->sizeof_register[regnum]);
> - gdb_assert (len >= 0 && offset + len <= m_descr->sizeof_register[regnum]);
> - /* Something to do? */
> - if (offset + len == 0)
> + gdb_assert (out != NULL);
> + gdb_assert (offset >= 0 && len >= 0 && offset + len <= reg_size);
> +
> + if (offset == 0 && len == 0)
> return REG_VALID;
> - /* Read (when needed) ... */
> +
> + if (offset == 0 && len == reg_size)
> + return (is_raw) ? raw_read (regnum, out) : cooked_read (regnum, out);
Could you add some comments to help the reader quickly know what's
going on? Something like:
if (offset == 0 && len == 0)
{
/* We don't read anything at all. */
return REG_VALID;
}
if (offset == 0 && len == reg_size)
{
/* We read the whole register. */
return (is_raw) ? raw_read (regnum, out) : cooked_read (regnum, out);
}
/* We read only part of the register. */
Same for write_part.
> @@ -355,9 +358,10 @@ private:
> int regnum, const void *in_buf,
> void *out_buf, size_t size) const;
>
> + /* Perform a partial register transfer using a read, modify, write
> + operation. */
> enum register_status write_part (int regnum, int offset, int len,
> - const void *out, bool is_raw);
> -
> + const gdb_byte *out, bool is_raw);
Rename out to in?
Thanks,
Simon
@@ -775,77 +775,75 @@ regcache::cooked_write (int regnum, const gdb_byte *buf)
regnum, buf);
}
-/* Perform a partial register transfer using a read, modify, write
- operation. */
+/* See regcache.h. */
enum register_status
-readable_regcache::read_part (int regnum, int offset, int len, void *in,
- bool is_raw)
+readable_regcache::read_part (int regnum, int offset, int len,
+ gdb_byte *out, bool is_raw)
{
- struct gdbarch *gdbarch = arch ();
- gdb_byte *reg = (gdb_byte *) alloca (register_size (gdbarch, regnum));
+ int reg_size = register_size (arch (), regnum);
- gdb_assert (in != NULL);
- gdb_assert (offset >= 0 && offset <= m_descr->sizeof_register[regnum]);
- gdb_assert (len >= 0 && offset + len <= m_descr->sizeof_register[regnum]);
- /* Something to do? */
- if (offset + len == 0)
+ gdb_assert (out != NULL);
+ gdb_assert (offset >= 0 && len >= 0 && offset + len <= reg_size);
+
+ if (offset == 0 && len == 0)
return REG_VALID;
- /* Read (when needed) ... */
+
+ if (offset == 0 && len == reg_size)
+ return (is_raw) ? raw_read (regnum, out) : cooked_read (regnum, out);
+
enum register_status status;
+ gdb_byte *reg = (gdb_byte *) alloca (reg_size);
- if (is_raw)
- status = raw_read (regnum, reg);
- else
- status = cooked_read (regnum, reg);
+ /* Read full register to buffer. */
+ status = (is_raw) ? raw_read (regnum, reg) : cooked_read (regnum, reg);
if (status != REG_VALID)
return status;
- /* ... modify ... */
- memcpy (in, reg + offset, len);
-
+ /* Copy out. */
+ memcpy (out, reg + offset, len);
return REG_VALID;
}
+/* See regcache.h. */
+
enum register_status
regcache::write_part (int regnum, int offset, int len,
- const void *out, bool is_raw)
+ const gdb_byte *in, bool is_raw)
{
- struct gdbarch *gdbarch = arch ();
- gdb_byte *reg = (gdb_byte *) alloca (register_size (gdbarch, regnum));
+ int reg_size = register_size (arch (), regnum);
- gdb_assert (out != NULL);
- gdb_assert (offset >= 0 && offset <= m_descr->sizeof_register[regnum]);
- gdb_assert (len >= 0 && offset + len <= m_descr->sizeof_register[regnum]);
- /* Something to do? */
- if (offset + len == 0)
+ gdb_assert (in != NULL);
+ gdb_assert (offset >= 0 && len >= 0 && offset + len <= reg_size);
+
+ if (offset == 0 && len == 0)
return REG_VALID;
- /* Read (when needed) ... */
- if (offset > 0
- || offset + len < m_descr->sizeof_register[regnum])
- {
- enum register_status status;
- if (is_raw)
- status = raw_read (regnum, reg);
- else
- status = cooked_read (regnum, reg);
- if (status != REG_VALID)
- return status;
+ if (offset == 0 && len == reg_size)
+ {
+ (is_raw) ? raw_write (regnum, in) : cooked_write (regnum, in);
+ return REG_VALID;
}
- memcpy (reg + offset, out, len);
- /* ... write (when needed). */
- if (is_raw)
- raw_write (regnum, reg);
- else
- cooked_write (regnum, reg);
+ enum register_status status;
+ gdb_byte *reg = (gdb_byte *) alloca (reg_size);
+
+ /* Read existing register to buffer. */
+ status = (is_raw) ? raw_read (regnum, reg) : cooked_read (regnum, reg);
+ if (status != REG_VALID)
+ return status;
+ /* Update buffer, then write back to regcache. */
+ memcpy (reg + offset, in, len);
+ is_raw ? raw_write (regnum, reg) : cooked_write (regnum, reg);
return REG_VALID;
}
+/* See regcache.h. */
+
enum register_status
-readable_regcache::raw_read_part (int regnum, int offset, int len, gdb_byte *buf)
+readable_regcache::raw_read_part (int regnum, int offset, int len,
+ gdb_byte *buf)
{
assert_regnum (regnum);
return read_part (regnum, offset, len, buf, true);
@@ -861,6 +859,8 @@ regcache::raw_write_part (int regnum, int offset, int len,
write_part (regnum, offset, len, buf, true);
}
+/* See regcache.h. */
+
enum register_status
readable_regcache::cooked_read_part (int regnum, int offset, int len,
gdb_byte *buf)
@@ -869,6 +869,8 @@ readable_regcache::cooked_read_part (int regnum, int offset, int len,
return read_part (regnum, offset, len, buf, false);
}
+/* See regcache.h. */
+
void
regcache::cooked_write_part (int regnum, int offset, int len,
const gdb_byte *buf)
@@ -253,8 +253,11 @@ public:
struct value *cooked_read_value (int regnum);
protected:
- enum register_status read_part (int regnum, int offset, int len, void *in,
- bool is_raw);
+
+ /* Perform a partial register transfer using a read, modify, write
+ operation. Will fail if register is currently invalid. */
+ enum register_status read_part (int regnum, int offset, int len,
+ gdb_byte *out, bool is_raw);
};
/* Buffer of registers, can be read and written. */
@@ -355,9 +358,10 @@ private:
int regnum, const void *in_buf,
void *out_buf, size_t size) const;
+ /* Perform a partial register transfer using a read, modify, write
+ operation. */
enum register_status write_part (int regnum, int offset, int len,
- const void *out, bool is_raw);
-
+ const gdb_byte *out, bool is_raw);
/* The address space of this register cache (for registers where it
makes sense, like PC or SP). */