[llvm-branch-commits] [llvm] [Dexter] Implement DexStepFunction and DexContinue (PR #152721)

[Orlando Cazalet-Hyams via llvm-branch-commits]

================
@@ -208,17 +297,92 @@ def _run_debugger_custom(self, cmdline):
                         exit_desired = True
                     bp_to_delete.append(bp_id)
                     del self._leading_bp_handles[bp_id]
-                # Add a range of trailing breakpoints covering the lines
-                # requested in the DexLimitSteps command. Ignore first line as
-                # that's covered by the leading bp we just hit and include the
-                # final line.
-                for line in range(bpr.range_from + 1, bpr.range_to + 1):
-                    self.debugger.add_breakpoint(bpr.path, line)
+
+                if bpr.function is not None:
+                    if step_info.frames:
+                        # Add this backtrace to the stack. While the current
+                        # backtrace matches the top of the stack we'll step,
+                        # and while there's a backtrace in the stack that
+                        # is a subset of the current backtrack we'll step-out.
+                        if (
+                            len(step_function_backtraces) == 0
+                            or backtrace != step_function_backtraces[-1]
+                        ):
+                            step_function_backtraces.append(backtrace)
+
+                            # Add an address breakpoint so we don't fall out
+                            # the end of nested DexStepFunctions with a DexContinue.
+                            addr = self.debugger.get_pc(frame_idx=1)
+                            instr_id = self.debugger.add_instruction_breakpoint(addr)
+                            # Note the breakpoint so we don't log the source location
+                            # it in the trace later.
+                            self.instr_bp_ids.add(instr_id)
+
+                elif bpr.is_continue:
+                    debugger_continue = True
+                    self.debugger.add_breakpoint(bpr.path, bpr.range_to)
+
+                else:
+                    # Add a range of trailing breakpoints covering the lines
+                    # requested in the DexLimitSteps command. Ignore first line as
+                    # that's covered by the leading bp we just hit and include the
+                    # final line.
+                    for line in range(bpr.range_from + 1, bpr.range_to + 1):
+                        id = self.debugger.add_breakpoint(bpr.path, line)
+                        self.context.logger.warning(
+                            f"Set trailing breakpoint {id} at {line}"
+                        )
 
             # Remove any trailing or expired leading breakpoints we just hit.
             self.debugger.delete_breakpoints(bp_to_delete)
 
+            debugger_next = False
+            debugger_out = False
+            if not debugger_continue and step_info.current_frame and step_info.frames:
+                while len(step_function_backtraces) > 0:
+                    match_subtrace = False  # Backtrace contains a target trace.
+                    match_trace = False  # Backtrace matches top of target stack.
+                    if len(backtrace) >= len(step_function_backtraces[-1]):
+                        match_subtrace = True
+                        match_trace = len(backtrace) == len(
+                            step_function_backtraces[-1]
+                        )
+                        for i, f in enumerate(reversed(step_function_backtraces[-1])):
+                            if backtrace[-1 - i] != f:
+                                match_subtrace = False
+                                match_trace = False
+                                break
----------------
OCHyams wrote:

👍 also added a comment to hopefully make it clearer  

https://github.com/llvm/llvm-project/pull/152721