Make VM debugger stop at every safe point

runtime/vm/debugger.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/debugger.h"
 
 #include "include/dart_api.h"
 
 #include "vm/code_generator.h"
 #include "vm/code_patcher.h"
@@ skipping 761 matching lines @@
 Debugger::Debugger()
     : isolate_(NULL),
       isolate_id_(ILLEGAL_ISOLATE_ID),
       initialized_(false),
       next_id_(1),
       stack_trace_(NULL),
       obj_cache_(NULL),
       src_breakpoints_(NULL),
       code_breakpoints_(NULL),
       resume_action_(kContinue),
-      last_bpt_line_(-1),
       ignore_breakpoints_(false),
       exc_pause_info_(kNoPauseOnExceptions) {
 }
 
 
 Debugger::~Debugger() {
   PortMap::ClosePort(isolate_id_);
   isolate_id_ = ILLEGAL_ISOLATE_ID;
   ASSERT(src_breakpoints_ == NULL);
   ASSERT(code_breakpoints_ == NULL);
@@ skipping 224 matching lines @@
   if (ignore_breakpoints_ ||
       (stack_trace_ != NULL) ||
       (event_handler_ == NULL) ||
       (exc_pause_info_ == kNoPauseOnExceptions)) {
     return;
   }
   DebuggerStackTrace* stack_trace = CollectStackTrace();
   if (!ShouldPauseOnException(stack_trace, exc)) {
     return;
   }
-  // No single-stepping possible after this pause event.
-  last_bpt_line_ = -1;
   ASSERT(stack_trace_ == NULL);
   stack_trace_ = stack_trace;
   ASSERT(obj_cache_ == NULL);
   obj_cache_ = new RemoteObjectCache(64);
   DebuggerEvent event;
   event.type = kExceptionThrown;
   event.exception = &exc;
   ASSERT(event_handler_ != NULL);
   (*event_handler_)(&event);
   stack_trace_ = NULL;
@@ skipping 486 matching lines @@
   if (FLAG_verbose_debug) {
     OS::Print(">>> hit %s breakpoint at %s:%"Pd" "
               "(token %"Pd") (address %#"Px")\n",
               bpt->IsInternal() ? "internal" : "user",
               String::Handle(bpt->SourceUrl()).ToCString(),
               bpt->LineNumber(),
               bpt->token_pos(),
               top_frame->pc());
   }
 
-  if (!bpt->IsInternal()) {
-    // This is a user-defined breakpoint so we call the breakpoint
-    // callback even if it is on the same line as the previous breakpoint.
-    last_bpt_line_ = -1;
-  }
-
-  bool notify_frontend =
-    (last_bpt_line_ < 0) || (last_bpt_line_ != bpt->LineNumber());
-
-  if (notify_frontend) {
-    resume_action_ = kContinue;
-    if (event_handler_ != NULL) {
-      ASSERT(stack_trace_ == NULL);
-      ASSERT(obj_cache_ == NULL);
-      obj_cache_ = new RemoteObjectCache(64);
-      stack_trace_ = stack_trace;
-      DebuggerEvent event;
-      event.type = kBreakpointReached;
-      ASSERT(stack_trace->Length() > 0);
-      event.top_frame = stack_trace->ActivationFrameAt(0);
-      (*event_handler_)(&event);
-      stack_trace_ = NULL;
-      obj_cache_ = NULL;  // Remote object cache is zone allocated.
-      last_bpt_line_ = bpt->LineNumber();
-    }
+  resume_action_ = kContinue;
+  if (event_handler_ != NULL) {
+    ASSERT(stack_trace_ == NULL);
+    ASSERT(obj_cache_ == NULL);
+    obj_cache_ = new RemoteObjectCache(64);
+    stack_trace_ = stack_trace;
+    DebuggerEvent event;
+    event.type = kBreakpointReached;
+    ASSERT(stack_trace->Length() > 0);
+    event.top_frame = stack_trace->ActivationFrameAt(0);
+    (*event_handler_)(&event);
+    stack_trace_ = NULL;
+    obj_cache_ = NULL;  // Remote object cache is zone allocated.
   }
 
   Function& currently_instrumented_func = Function::Handle();
   if (bpt->IsInternal()) {
     currently_instrumented_func = bpt->function();
   }
   Function& func_to_instrument = Function::Handle();
   if (resume_action_ == kContinue) {
     // Nothing to do here, any potential instrumentation will be removed
     // below.
@@ skipping 79 matching lines @@
     ASSERT(resume_action_ == kStepOut);
     // Set stepping breakpoints in the caller.
     if (stack_trace->Length() > 1) {
       ActivationFrame* caller_frame = stack_trace->ActivationFrameAt(1);
       func_to_instrument = caller_frame->function().raw();
     }
   }
 
   if (func_to_instrument.IsNull() ||
       (func_to_instrument.raw() != currently_instrumented_func.raw())) {
-    last_bpt_line_ = -1;
     RemoveInternalBreakpoints();  // *bpt is now invalid.
     if (!func_to_instrument.IsNull()) {
       InstrumentForStepping(func_to_instrument);
     }
   }
 }
 
 
 void Debugger::Initialize(Isolate* isolate) {
   if (initialized_) {
@@ skipping 171 matching lines @@
 }
 
 
 void Debugger::RegisterCodeBreakpoint(CodeBreakpoint* bpt) {
   ASSERT(bpt->next() == NULL);
   bpt->set_next(code_breakpoints_);
   code_breakpoints_ = bpt;
 }
 
 }  // namespace dart