/* Displaced stepping related things.
- Copyright (C) 2020 Free Software Foundation, Inc.
+ Copyright (C) 2020-2022 Free Software Foundation, Inc.
This file is part of GDB.
#ifndef DISPLACED_STEPPING_H
#define DISPLACED_STEPPING_H
+#include "gdbsupport/array-view.h"
+#include "gdbsupport/byte-vector.h"
+
+struct gdbarch;
+struct thread_info;
+
+/* True if we are debugging displaced stepping. */
+
+extern bool debug_displaced;
+
+/* Print a "displaced" debug statement. */
+
+#define displaced_debug_printf(fmt, ...) \
+ debug_prefixed_printf_cond (debug_displaced, "displaced",fmt, ##__VA_ARGS__)
+
enum displaced_step_prepare_status
{
/* A displaced stepping buffer was successfully allocated and prepared. */
DISPLACED_STEP_FINISH_STATUS_NOT_EXECUTED,
};
+/* Data returned by a gdbarch displaced_step_copy_insn method, to be passed to
+ the matching displaced_step_fixup method. */
+
+struct displaced_step_copy_insn_closure
+{
+ virtual ~displaced_step_copy_insn_closure () = 0;
+};
+
+using displaced_step_copy_insn_closure_up
+ = std::unique_ptr<displaced_step_copy_insn_closure>;
+
+/* A simple displaced step closure that contains only a byte buffer. */
+
+struct buf_displaced_step_copy_insn_closure : displaced_step_copy_insn_closure
+{
+ buf_displaced_step_copy_insn_closure (int buf_size)
+ : buf (buf_size)
+ {}
+
+ /* The content of this buffer is up to the user of the class, but typically
+ original instruction bytes, used during fixup to determine what needs to
+ be fixed up. */
+ gdb::byte_vector buf;
+};
+
+/* Per-inferior displaced stepping state. */
+
+struct displaced_step_inferior_state
+{
+ displaced_step_inferior_state ()
+ {
+ reset ();
+ }
+
+ /* Put this object back in its original state. */
+ void reset ()
+ {
+ failed_before = false;
+ in_progress_count = 0;
+ unavailable = false;
+ }
+
+ /* True if preparing a displaced step ever failed. If so, we won't
+ try displaced stepping for this inferior again. */
+ bool failed_before;
+
+ /* Number of displaced steps in progress for this inferior. */
+ unsigned int in_progress_count;
+
+ /* If true, this tells GDB that it's not worth asking the gdbarch displaced
+ stepping implementation to prepare a displaced step, because it would
+ return UNAVAILABLE. This is set and reset by the gdbarch in the
+ displaced_step_prepare and displaced_step_finish methods. */
+ bool unavailable;
+};
+
+/* Per-thread displaced stepping state. */
+
+struct displaced_step_thread_state
+{
+ /* Return true if this thread is currently executing a displaced step. */
+ bool in_progress () const
+ {
+ return m_original_gdbarch != nullptr;
+ }
+
+ /* Return the gdbarch of the thread prior to the step. */
+ gdbarch *get_original_gdbarch () const
+ {
+ return m_original_gdbarch;
+ }
+
+ /* Mark this thread as currently executing a displaced step.
+
+ ORIGINAL_GDBARCH is the current gdbarch of the thread (before the step
+ is executed). */
+ void set (gdbarch *original_gdbarch)
+ {
+ m_original_gdbarch = original_gdbarch;
+ }
+
+ /* Mark this thread as no longer executing a displaced step. */
+ void reset ()
+ {
+ m_original_gdbarch = nullptr;
+ }
+
+private:
+ gdbarch *m_original_gdbarch = nullptr;
+};
+
+/* Control access to multiple displaced stepping buffers at fixed addresses. */
+
+struct displaced_step_buffers
+{
+ explicit displaced_step_buffers (gdb::array_view<CORE_ADDR> buffer_addrs)
+ {
+ gdb_assert (buffer_addrs.size () > 0);
+
+ m_buffers.reserve (buffer_addrs.size ());
+
+ for (CORE_ADDR buffer_addr : buffer_addrs)
+ m_buffers.emplace_back (buffer_addr);
+ }
+
+ displaced_step_prepare_status prepare (thread_info *thread,
+ CORE_ADDR &displaced_pc);
+
+ displaced_step_finish_status finish (gdbarch *arch, thread_info *thread,
+ gdb_signal sig);
+
+ const displaced_step_copy_insn_closure *
+ copy_insn_closure_by_addr (CORE_ADDR addr);
+
+ void restore_in_ptid (ptid_t ptid);
+
+private:
+
+ /* State of a single buffer. */
+
+ struct displaced_step_buffer
+ {
+ explicit displaced_step_buffer (CORE_ADDR addr)
+ : addr (addr)
+ {}
+
+ /* Address of the buffer. */
+ const CORE_ADDR addr;
+
+ /* The original PC of the instruction currently being stepped. */
+ CORE_ADDR original_pc = 0;
+
+ /* If set, the thread currently using the buffer. If unset, the buffer is not
+ used. */
+ thread_info *current_thread = nullptr;
+
+ /* Saved copy of the bytes in the displaced buffer, to be restored once the
+ buffer is no longer used. */
+ gdb::byte_vector saved_copy;
+
+ /* Closure obtained from gdbarch_displaced_step_copy_insn, to be passed to
+ gdbarch_displaced_step_fixup_insn. */
+ displaced_step_copy_insn_closure_up copy_insn_closure;
+ };
+
+ std::vector<displaced_step_buffer> m_buffers;
+};
+
#endif /* DISPLACED_STEPPING_H */
projects / binutils-gdb.git / blobdiff