[v7,01/10] btrace: Introduce auxiliary instructions.
Commit Message
Auxiliary instructions are pseudo instructions pointing to auxiliary data.
This auxiliary data can be printed in all commands displaying (record
function-call-history, record instruction-history) or stepping through
(stepi etc.) the execution history, which will be introduced in the next
commits.
This patch is in preparation for the new ptwrite feature, which is based on
auxiliary instructions.
---
gdb/btrace.c | 2 ++
gdb/btrace.h | 24 +++++++++++++++++++++---
gdb/doc/gdb.texinfo | 3 +++
3 files changed, 26 insertions(+), 3 deletions(-)
Comments
> Date: Fri, 21 Oct 2022 13:59:38 +0200
> From: Felix Willgerodt via Gdb-patches <gdb-patches@sourceware.org>
>
> Auxiliary instructions are pseudo instructions pointing to auxiliary data.
> This auxiliary data can be printed in all commands displaying (record
> function-call-history, record instruction-history) or stepping through
> (stepi etc.) the execution history, which will be introduced in the next
> commits.
>
> This patch is in preparation for the new ptwrite feature, which is based on
> auxiliary instructions.
> ---
> gdb/btrace.c | 2 ++
> gdb/btrace.h | 24 +++++++++++++++++++++---
> gdb/doc/gdb.texinfo | 3 +++
> 3 files changed, 26 insertions(+), 3 deletions(-)
Thanks, the documentation part is OK.
@@ -1823,6 +1823,8 @@ btrace_clear_history (struct btrace_thread_info *btinfo)
btinfo->insn_history = NULL;
btinfo->call_history = NULL;
btinfo->replay = NULL;
+
+ btinfo->aux_data.clear ();
}
/* Clear the branch trace maintenance histories in BTINFO. */
@@ -52,7 +52,10 @@ enum btrace_insn_class
BTRACE_INSN_RETURN,
/* The instruction is an unconditional jump. */
- BTRACE_INSN_JUMP
+ BTRACE_INSN_JUMP,
+
+ /* The instruction is a pseudo instruction containing auxiliary data. */
+ BTRACE_INSN_AUX
};
/* Instruction flags. */
@@ -68,8 +71,19 @@ DEF_ENUM_FLAGS_TYPE (enum btrace_insn_flag, btrace_insn_flags);
This represents a single instruction in a branch trace. */
struct btrace_insn
{
- /* The address of this instruction. */
- CORE_ADDR pc;
+ union
+ {
+ /* The address of this instruction. Applies to btrace_insn with
+ iclass == BTRACE_INSN_OTHER or
+ iclass == BTRACE_INSN_CALL or
+ iclass == BTRACE_INSN_RETURN or
+ iclass == BTRACE_INSN_JUMP. */
+ CORE_ADDR pc;
+
+ /* Index into btrace_info::aux_data. Applies to btrace_insn with
+ iclass == BTRACE_INSN_AUX. */
+ uint64_t aux_data_index;
+ };
/* The size of this instruction in bytes. */
gdb_byte size;
@@ -330,6 +344,10 @@ struct btrace_thread_info
function segment i will be at index (i - 1). */
std::vector<btrace_function> functions;
+ /* Optional auxiliary information that is printed in all commands
+ displaying or stepping through the execution history. */
+ std::vector<std::string> aux_data;
+
/* The function level offset. When added to each function's LEVEL,
this normalizes the function levels such that the smallest level
becomes zero. */
@@ -7545,6 +7545,9 @@ Moxie, PowerPC, PowerPC64, S/390, and x86 (i386/amd64) running
GNU/Linux. Process record and replay can be used both when native
debugging, and when remote debugging via @code{gdbserver}.
+When recording an inferior, @value{GDBN} may print auxiliary information
+during stepping commands and commands displaying the execution history.
+
For architecture environments that support process record and replay,
@value{GDBN} provides the following commands: