[PATCH v7 06/18] [gdbserver/generic] Convert tdesc's expedite_regs to a string vector

Luis Machado via Gdb-patches
2023-09-18T21:29:07Z

Right now the list of expedited registers is stored as an array of char *,
with a nullptr element at the end to signal its last element.

Convert expedite_regs to a std::vector of std::string so it is easier to
manage the elements and the storage is handled automatically.

Eventually we might want to convert all the target functions so they pass a
std::vector of std::string as well. Or maybe expose an interface that target can
use to add expedited registers on-by-one depending on the target description
discovery needs, as opposed to just a static list of char *.

Reviewed-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
Approved-By: Tom Tromey <tom@tromey.com>
---
gdbserver/remote-utils.cc | 13 +++++--------
gdbserver/tdesc.cc | 23 ++++++++++++++---------
gdbserver/tdesc.h | 4 ++--
3 files changed, 21 insertions(+), 19 deletions(-)

diff --git a/gdbserver/remote-utils.cc b/gdbserver/remote-utils.cc
index 722915d30f2..fb5c38d4522 100644
--- a/gdbserver/remote-utils.cc
+++ b/gdbserver/remote-utils.cc
@@ -1068,7 +1068,6 @@ prepare_resume_reply (char *buf, ptid_t ptid, const target_waitstatus &status)
case TARGET_WAITKIND_SYSCALL_ENTRY:
case TARGET_WAITKIND_SYSCALL_RETURN:
{
- const char **regp;
struct regcache *regcache;
char *buf_start = buf;

@@ -1155,8 +1154,6 @@ prepare_resume_reply (char *buf, ptid_t ptid, const target_waitstatus &status)

switch_to_thread (the_target, ptid);

- regp = current_target_desc ()->expedite_regs;
-
regcache = get_thread_regcache (current_thread, 1);

if (the_target->stopped_by_watchpoint ())
@@ -1188,11 +1185,11 @@ prepare_resume_reply (char *buf, ptid_t ptid, const target_waitstatus &status)
buf += strlen (buf);
}

- while (*regp)
- {
- buf = outreg (regcache, find_regno (regcache->tdesc, *regp), buf);
- regp ++;
- }
+ /* Handle the expedited registers. */
+ for (const std::string &expedited_reg :
+ current_target_desc ()->expedite_regs)
+ buf = outreg (regcache, find_regno (regcache->tdesc,
+ expedited_reg.c_str ()), buf);
*buf = '\0';

/* Formerly, if the debugger had not used any thread features
diff --git a/gdbserver/tdesc.cc b/gdbserver/tdesc.cc
index 2c7257c458f..072b88481b2 100644
--- a/gdbserver/tdesc.cc
+++ b/gdbserver/tdesc.cc
@@ -32,14 +32,13 @@ bool target_desc::operator== (const target_desc &other) const
if (reg_defs != other.reg_defs)
return false;

- /* Compare expedite_regs. */
- int i = 0;
- for (; expedite_regs[i] != NULL; i++)
- {
- if (strcmp (expedite_regs[i], other.expedite_regs[i]) != 0)
- return false;
- }
- if (other.expedite_regs[i] != NULL)
+ /* Compare the two vectors of expedited registers. They will only match
+ if the following conditions are met:
+
+ - Both vectors have the same number of elements.
+ - Both vectors contain the same elements.
+ - The elements of both vectors appear in the same order. */
+ if (expedite_regs != other.expedite_regs)
return false;

return true;
@@ -89,7 +88,13 @@ init_target_desc (struct target_desc *tdesc,
gdb_assert (2 * tdesc->registers_size + 32 <= PBUFSIZ);

#ifndef IN_PROCESS_AGENT
- tdesc->expedite_regs = expedite_regs;
+ /* Drop the contents of the previous vector, if any. */
+ tdesc->expedite_regs.clear ();
+
+ /* Initialize the vector with new expedite registers contents. */
+ int expedite_count = 0;
+ while (expedite_regs[expedite_count] != nullptr)
+ tdesc->expedite_regs.push_back (expedite_regs[expedite_count++]);
#endif
}

diff --git a/gdbserver/tdesc.h b/gdbserver/tdesc.h
index 7fe7d0d8eb3..8a29fc6fe6d 100644
--- a/gdbserver/tdesc.h
+++ b/gdbserver/tdesc.h
@@ -40,9 +40,9 @@ struct target_desc final : tdesc_element
std::vector<tdesc_feature_up> features;

#ifndef IN_PROCESS_AGENT
- /* An array of register names. These are the "expedite" registers:
+ /* A vector of register names. These are the "expedite" registers:
registers whose values are sent along with stop replies. */
- const char **expedite_regs = NULL;
+ std::vector<std::string> expedite_regs;

/* Defines what to return when looking for the "target.xml" file in
response to qXfer:features:read. Its contents can either be
--
2.25.1