Reapply "Per-closure breakpoints; restructure breakpoint implementation to keep a list of condition…

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 45 matching lines @@
   }
 
  private:
   GrowableObjectArray* objs_;
 
   DISALLOW_COPY_AND_ASSIGN(RemoteObjectCache);
 };
 
 
 // Create an unresolved breakpoint in given token range and script.
-SourceBreakpoint::SourceBreakpoint(intptr_t id,
-                                   const Script& script,
-                                   intptr_t token_pos,
-                                   intptr_t end_token_pos)
-    : id_(id),
-      script_(script.raw()),
+BreakpointLocation::BreakpointLocation(const Script& script,
+                                       intptr_t token_pos,
+                                       intptr_t end_token_pos)
+    : script_(script.raw()),
       url_(script.url()),
       token_pos_(token_pos),
       end_token_pos_(end_token_pos),
       is_resolved_(false),
-      is_enabled_(false),
-      is_one_shot_(false),
       next_(NULL),
+      conditions_(NULL),
       function_(Function::null()),
       line_number_(-1) {
-  ASSERT(id_ > 0);
   ASSERT(!script.IsNull());
   ASSERT(token_pos_ >= 0);
 }
 
 // Create a latent breakpoint at given url and line number.
-SourceBreakpoint::SourceBreakpoint(intptr_t id,
-                                   const String& url,
-                                   intptr_t line_number)
-    : id_(id),
-      script_(Script::null()),
+BreakpointLocation::BreakpointLocation(const String& url,
+                                       intptr_t line_number)
+    : script_(Script::null()),
       url_(url.raw()),
       token_pos_(-1),
       end_token_pos_(-1),
       is_resolved_(false),
-      is_enabled_(false),
-      is_one_shot_(false),
       next_(NULL),
+      conditions_(NULL),
       function_(Function::null()),
       line_number_(line_number) {
-  ASSERT(id >= 0);
   ASSERT(line_number_ >= 0);
 }
 
-void SourceBreakpoint::Enable() {
-  is_enabled_ = true;
-  Isolate::Current()->debugger()->SyncBreakpoint(this);
+
+BreakpointLocation::~BreakpointLocation() {
+  Breakpoint* bpt = breakpoints();
+  while (bpt != NULL) {
+    Breakpoint* temp = bpt;
+    bpt = bpt->next();
+    delete temp;
+  }
 }
 
 
-void SourceBreakpoint::Disable() {
-  is_enabled_ = false;
-  Isolate::Current()->debugger()->SyncBreakpoint(this);
+bool BreakpointLocation::AnyEnabled() const {
+  return breakpoints() != NULL;
 }
 
 
-void SourceBreakpoint::SetResolved(const Function& func, intptr_t token_pos) {
+void BreakpointLocation::SetResolved(const Function& func, intptr_t token_pos) {
   ASSERT(!IsLatent());
   ASSERT(func.script() == script_);
   ASSERT((func.token_pos() <= token_pos) &&
          (token_pos <= func.end_token_pos()));
   ASSERT(func.is_debuggable());
   function_ = func.raw();
   token_pos_ = token_pos;
   end_token_pos_ = token_pos;
   line_number_ = -1;  // Recalculate lazily.
   is_resolved_ = true;
 }
 
 
 // TODO(hausner): Get rid of library parameter. A source breakpoint location
 // does not imply a library, since the same source code can be included
 // in more than one library, e.g. the text location of mixin functions.
-void SourceBreakpoint::GetCodeLocation(Library* lib,
-                                       Script* script,
-                                       intptr_t* pos) {
+void BreakpointLocation::GetCodeLocation(Library* lib,
+                                         Script* script,
+                                         intptr_t* pos) {
   if (IsLatent()) {
     *lib = Library::null();
     *script = Script::null();
     *pos = -1;
   } else {
     *script = this->script();
     *pos = token_pos_;
     if (IsResolved()) {
       const Function& func = Function::Handle(function_);
       ASSERT(!func.IsNull());
       const Class& cls = Class::Handle(func.origin());
       *lib = cls.library();
     } else {
       *lib = Library::null();
     }
   }
 }
 
 
-intptr_t SourceBreakpoint::LineNumber() {
+intptr_t BreakpointLocation::LineNumber() {
   // Latent breakpoints must have a requested line number >= 0.
   ASSERT(!IsLatent() || line_number_ >= 0);
   // Compute line number lazily since it causes scanning of the script.
   if (line_number_ < 0) {
     const Script& script = Script::Handle(this->script());
     script.GetTokenLocation(token_pos_, &line_number_, NULL);
   }
   return line_number_;
 }
 
 
-void SourceBreakpoint::VisitObjectPointers(ObjectPointerVisitor* visitor) {
+void Breakpoint::set_bpt_location(BreakpointLocation* new_bpt_location) {
+  ASSERT(bpt_location_->IsLatent());  // Only reason to move.
+  bpt_location_ = new_bpt_location;
+}
+
+
+void Breakpoint::VisitObjectPointers(ObjectPointerVisitor* visitor) {
+  visitor->VisitPointer(reinterpret_cast<RawObject**>(&closure_));
+}
+
+
+void BreakpointLocation::VisitObjectPointers(ObjectPointerVisitor* visitor) {
   visitor->VisitPointer(reinterpret_cast<RawObject**>(&script_));
   visitor->VisitPointer(reinterpret_cast<RawObject**>(&url_));
   visitor->VisitPointer(reinterpret_cast<RawObject**>(&function_));
+
+  Breakpoint* bpt = conditions_;
+  while (bpt != NULL) {
+    bpt -> VisitObjectPointers(visitor);
+    bpt = bpt->next();
+  }
 }
 
 
-void SourceBreakpoint::PrintJSON(JSONStream* stream) {
+void Breakpoint::PrintJSON(JSONStream* stream) {
   Isolate* isolate = Isolate::Current();
 
   JSONObject jsobj(stream);
   jsobj.AddProperty("type", "Breakpoint");
 
   jsobj.AddFixedServiceId("breakpoints/%" Pd "", id());
   jsobj.AddProperty("breakpointNumber", id());
-  jsobj.AddProperty("resolved", IsResolved());
+  jsobj.AddProperty("resolved", bpt_location_->IsResolved());
 
   Library& library = Library::Handle(isolate);
   Script& script = Script::Handle(isolate);
   intptr_t token_pos;
-  GetCodeLocation(&library, &script, &token_pos);
+  bpt_location_->GetCodeLocation(&library, &script, &token_pos);
   {
     JSONObject location(&jsobj, "location");
     location.AddProperty("type", "Location");
     location.AddProperty("script", script);
     location.AddProperty("tokenPos", token_pos);
   }
 }
 
 
 void CodeBreakpoint::VisitObjectPointers(ObjectPointerVisitor* visitor) {
@@ skipping 88 matching lines @@
     Debugger* debugger = Isolate::Current()->debugger();
     ASSERT(debugger != NULL);
     debugger->SignalIsolateEvent(DebuggerEvent::kIsolateInterrupted);
   }
 }
 
 
 // The vm service handles breakpoint notifications in a different way
 // than the regular debugger breakpoint notifications.
 static void SendServiceBreakpointEvent(ServiceEvent::EventType type,
-                                       SourceBreakpoint* bpt) {
+                                       Breakpoint* bpt) {
   if (Service::NeedsEvents()) {
     ServiceEvent service_event(Isolate::Current(), type);
     service_event.set_breakpoint(bpt);
     Service::HandleEvent(&service_event);
   }
 }
 
 
+void BreakpointLocation::AddBreakpoint(Breakpoint* bpt, Debugger* dbg) {
+  bpt->set_next(breakpoints());
+  set_breakpoints(bpt);
+
+  dbg->SyncBreakpointLocation(this);
+
+  if (IsResolved()) {
+    dbg->SignalBpResolved(bpt);
+  }
+  SendServiceBreakpointEvent(ServiceEvent::kBreakpointAdded, bpt);
+}
+
+
+Breakpoint* BreakpointLocation::AddRepeated(Debugger* dbg) {
+  Breakpoint* bpt = breakpoints();
+  while (bpt != NULL) {
+    if (bpt->IsRepeated()) break;
+    bpt = bpt->next();
+  }
+  if (bpt == NULL) {
+    bpt = new Breakpoint(dbg->nextId(), this);
+    bpt->SetIsRepeated();
+    AddBreakpoint(bpt, dbg);
+  }
+  return bpt;
+}
+
+
+Breakpoint* BreakpointLocation::AddSingleShot(Debugger* dbg) {
+  Breakpoint* bpt = breakpoints();
+  while (bpt != NULL) {
+    if (bpt->IsSingleShot()) break;
+    bpt = bpt->next();
+  }
+  if (bpt == NULL) {
+    bpt = new Breakpoint(dbg->nextId(), this);
+    bpt->SetIsSingleShot();
+    AddBreakpoint(bpt, dbg);
+  }
+  return bpt;
+}
+
+
+Breakpoint* BreakpointLocation::AddPerClosure(Debugger* dbg,
+                                              const Instance& closure) {
+  Breakpoint* bpt = breakpoints();
+  while (bpt != NULL) {
+    if (bpt->IsPerClosure() && bpt->closure() == closure.raw()) break;
+    bpt = bpt->next();
+  }
+  if (bpt == NULL) {
+    bpt = new Breakpoint(dbg->nextId(), this);
+    bpt->SetIsPerClosure(closure);
+    AddBreakpoint(bpt, dbg);
+  }
+  return bpt;
+}
+
+
 const char* Debugger::QualifiedFunctionName(const Function& func) {
   const String& func_name = String::Handle(func.name());
   Class& func_class = Class::Handle(func.Owner());
   String& class_name = String::Handle(func_class.Name());
 
   const char* kFormat = "%s%s%s";
   intptr_t len = OS::SNPrint(NULL, 0, kFormat,
       func_class.IsTopLevel() ? "" : class_name.ToCString(),
       func_class.IsTopLevel() ? "" : ".",
       func_name.ToCString());
@@ skipping 20 matching lines @@
 }
 
 
 bool Debugger::HasBreakpoint(const Function& func) {
   if (!func.HasCode()) {
     // If the function is not compiled yet, just check whether there
     // is a user-defined breakpoint that falls into the token
     // range of the function. This may be a false positive: the breakpoint
     // might be inside a local closure.
     Script& script = Script::Handle(isolate_);
-    SourceBreakpoint* sbpt = src_breakpoints_;
+    BreakpointLocation* sbpt = breakpoint_locations_;
     while (sbpt != NULL) {
       script = sbpt->script();
       if (FunctionContains(func, script, sbpt->token_pos())) {
         return true;
       }
       sbpt = sbpt->next_;
     }
     return false;
   }
   CodeBreakpoint* cbpt = code_breakpoints_;
@@ skipping 13 matching lines @@
     if (code.raw() == cbpt->code_) {
       return true;
     }
     cbpt = cbpt->next_;
   }
   return false;
 }
 
 
 void Debugger::PrintBreakpointsToJSONArray(JSONArray* jsarr) const {
-  SourceBreakpoint* sbpt = src_breakpoints_;
+  BreakpointLocation* sbpt = breakpoint_locations_;
   while (sbpt != NULL) {
-    jsarr->AddValue(sbpt);
+    Breakpoint* bpt = sbpt->breakpoints();
+    while (bpt != NULL) {
+      jsarr->AddValue(bpt);
+      bpt = bpt->next();
+    }
     sbpt = sbpt->next_;
   }
 }
 
 
 RawString* ActivationFrame::QualifiedFunctionName() {
   return String::New(Debugger::QualifiedFunctionName(function()));
 }
 
 
@@ skipping 276 matching lines @@
   vars_initialized_ = true;
 }
 
 
 intptr_t ActivationFrame::NumLocalVariables() {
   GetDescIndices();
   return desc_indices_.length();
 }
 
 
+RawObject* ActivationFrame::GetParameter(intptr_t index) {
+  intptr_t num_parameters = function().num_fixed_parameters();
+  ASSERT(0 <= index && index < num_parameters);
+  intptr_t reverse_index = num_parameters - index;
+
+  if (function().NumOptionalParameters() > 0) {
+    // If the function has optional parameters, the first positional parameter
+    // can be in a number of places in the caller's frame depending on how many
+    // were actually supplied at the call site, but they are copied to a fixed
+    // place in the callee's frame.
+    uword var_address = fp() + ((kFirstLocalSlotFromFp - index) * kWordSize);
+    return reinterpret_cast<RawObject*>(
+        *reinterpret_cast<uword*>(var_address));
+  } else {
+    uword var_address = fp() + (kParamEndSlotFromFp * kWordSize)
+                             + (reverse_index * kWordSize);
+    return reinterpret_cast<RawObject*>(
+        *reinterpret_cast<uword*>(var_address));
+  }
+}
+
+
+RawObject* ActivationFrame::GetClosure() {
+  ASSERT(function().IsClosureFunction());
+  return GetParameter(0);
+}
+
+
 RawObject* ActivationFrame::GetLocalVar(intptr_t slot_index) {
   if (deopt_frame_.IsNull()) {
     uword var_address = fp() + slot_index * kWordSize;
     return reinterpret_cast<RawObject*>(
         *reinterpret_cast<uword*>(var_address));
   } else {
     return deopt_frame_.At(deopt_frame_offset_ + slot_index);
   }
 }
 
@@ skipping 250 matching lines @@
 
 CodeBreakpoint::CodeBreakpoint(const Code& code,
                                intptr_t token_pos,
                                uword pc,
                                RawPcDescriptors::Kind kind)
     : code_(code.raw()),
       token_pos_(token_pos),
       pc_(pc),
       line_number_(-1),
       is_enabled_(false),
-      src_bpt_(NULL),
+      bpt_location_(NULL),
       next_(NULL),
       breakpoint_kind_(kind),
       saved_value_(0) {
   ASSERT(!code.IsNull());
   ASSERT(token_pos_ > 0);
   ASSERT(pc_ != 0);
   ASSERT((breakpoint_kind_ & kSafepointKind) != 0);
 }
 
 
 CodeBreakpoint::~CodeBreakpoint() {
   // Make sure we don't leave patched code behind.
   ASSERT(!IsEnabled());
   // Poison the data so we catch use after free errors.
 #ifdef DEBUG
   code_ = Code::null();
   pc_ = 0ul;
-  src_bpt_ = NULL;
+  bpt_location_ = NULL;
   next_ = NULL;
   breakpoint_kind_ = RawPcDescriptors::kOther;
 #endif
 }
 
 
 RawFunction* CodeBreakpoint::function() const {
   return Code::Handle(code_).function();
 }
 
@@ skipping 58 matching lines @@
   ASSERT(IsValidId(obj_id));
   return objs_->At(obj_id);
 }
 
 
 Debugger::Debugger()
     : isolate_(NULL),
       isolate_id_(ILLEGAL_ISOLATE_ID),
       initialized_(false),
       next_id_(1),
-      latent_breakpoints_(NULL),
-      src_breakpoints_(NULL),
+      latent_locations_(NULL),
+      breakpoint_locations_(NULL),
       code_breakpoints_(NULL),
       resume_action_(kContinue),
       ignore_breakpoints_(false),
       pause_event_(NULL),
       obj_cache_(NULL),
       stack_trace_(NULL),
       stepping_fp_(0),
       exc_pause_info_(kNoPauseOnExceptions) {
 }
 
 
 Debugger::~Debugger() {
   isolate_id_ = ILLEGAL_ISOLATE_ID;
   ASSERT(!IsPaused());
-  ASSERT(latent_breakpoints_ == NULL);
-  ASSERT(src_breakpoints_ == NULL);
+  ASSERT(latent_locations_ == NULL);
+  ASSERT(breakpoint_locations_ == NULL);
   ASSERT(code_breakpoints_ == NULL);
   ASSERT(stack_trace_ == NULL);
   ASSERT(obj_cache_ == NULL);
 }
 
 
 void Debugger::Shutdown() {
-  while (src_breakpoints_ != NULL) {
-    SourceBreakpoint* bpt = src_breakpoints_;
-    src_breakpoints_ = src_breakpoints_->next();
+  while (breakpoint_locations_ != NULL) {
+    BreakpointLocation* bpt = breakpoint_locations_;
+    breakpoint_locations_ = breakpoint_locations_->next();
     delete bpt;
   }
-  while (latent_breakpoints_ != NULL) {
-    SourceBreakpoint* bpt = latent_breakpoints_;
-    latent_breakpoints_ = latent_breakpoints_->next();
+  while (latent_locations_ != NULL) {
+    BreakpointLocation* bpt = latent_locations_;
+    latent_locations_ = latent_locations_->next();
     delete bpt;
   }
   while (code_breakpoints_ != NULL) {
     CodeBreakpoint* bpt = code_breakpoints_;
     code_breakpoints_ = code_breakpoints_->next();
     bpt->Disable();
     delete bpt;
   }
   // Signal isolate shutdown event.
   if (!ServiceIsolate::IsServiceIsolateDescendant(isolate_)) {
@@ skipping 97 matching lines @@
           if (function.HasOptimizedCode()) {
             function.SwitchToUnoptimizedCode();
           }
         }
       }
     }
   }
 }
 
 
-void Debugger::SignalBpResolved(SourceBreakpoint* bpt) {
-  if (HasEventHandler() && !bpt->IsOneShot()) {
+void Debugger::SignalBpResolved(Breakpoint* bpt) {
+  if (HasEventHandler() && !bpt->IsSingleShot()) {
     DebuggerEvent event(isolate_, DebuggerEvent::kBreakpointResolved);
     event.set_breakpoint(bpt);
     InvokeEventHandler(&event);
   }
 }
 
 
 ActivationFrame* Debugger::CollectDartFrame(Isolate* isolate,
                                             uword pc,
                                             StackFrame* frame,
@@ skipping 297 matching lines @@
   // We didn't find a safe point in the given token range. Try and find
   // a safe point in the remaining source code of the function.
   if (last_token_pos < func.end_token_pos()) {
     return ResolveBreakpointPos(func, last_token_pos, func.end_token_pos());
   }
   return -1;
 }
 
 
 void Debugger::MakeCodeBreakpointAt(const Function& func,
-                                    SourceBreakpoint* bpt) {
-  ASSERT(bpt->token_pos_ != Scanner::kNoSourcePos);
-  ASSERT((bpt != NULL) && bpt->IsResolved());
+                                    BreakpointLocation* loc) {
+  ASSERT(loc->token_pos_ != Scanner::kNoSourcePos);
+  ASSERT((loc != NULL) && loc->IsResolved());
   ASSERT(!func.HasOptimizedCode());
   Code& code = Code::Handle(func.unoptimized_code());
   ASSERT(!code.IsNull());
   PcDescriptors& desc = PcDescriptors::Handle(code.pc_descriptors());
   uword lowest_pc_offset = kUwordMax;
   RawPcDescriptors::Kind lowest_kind = RawPcDescriptors::kAnyKind;
   // Find the safe point with the lowest compiled code address
   // that maps to the token position of the source breakpoint.
   PcDescriptors::Iterator iter(desc, kSafepointKind);
   while (iter.MoveNext()) {
-    if (iter.TokenPos() == bpt->token_pos_) {
+    if (iter.TokenPos() == loc->token_pos_) {
       if (iter.PcOffset() < lowest_pc_offset) {
         lowest_pc_offset = iter.PcOffset();
         lowest_kind = iter.Kind();
       }
     }
   }
   if (lowest_pc_offset == kUwordMax) {
     return;
   }
   uword lowest_pc = code.EntryPoint() + lowest_pc_offset;
   CodeBreakpoint* code_bpt = GetCodeBreakpoint(lowest_pc);
   if (code_bpt == NULL) {
     // No code breakpoint for this code exists; create one.
-    code_bpt = new CodeBreakpoint(code, bpt->token_pos_,
+    code_bpt = new CodeBreakpoint(code, loc->token_pos_,
                                   lowest_pc, lowest_kind);
     RegisterCodeBreakpoint(code_bpt);
   }
-  code_bpt->set_src_bpt(bpt);
-  if (bpt->IsEnabled()) {
+  code_bpt->set_bpt_location(loc);
+  if (loc->AnyEnabled()) {
     code_bpt->Enable();
   }
 }
 
 
 void Debugger::FindCompiledFunctions(const Script& script,
                                      intptr_t start_pos,
                                      intptr_t end_pos,
                                      GrowableObjectArray* function_list) {
   Class& cls = Class::Handle(isolate_);
@@ skipping 131 matching lines @@
             SelectBestFit(&best_fit, &function);
           }
         }
       }
     }
   }
   return best_fit.raw();
 }
 
 
-SourceBreakpoint* Debugger::SetBreakpoint(const Script& script,
+BreakpointLocation* Debugger::SetBreakpoint(const Script& script,
                                           intptr_t token_pos,
                                           intptr_t last_token_pos) {
   Function& func = Function::Handle(isolate_);
   func = FindBestFit(script, token_pos);
   if (func.IsNull()) {
     return NULL;
   }
   // There may be more than one function object for a given function
   // in source code. There may be implicit closure functions, and
   // there may be copies of mixin functions. Collect all compiled
   // functions whose source code range matches exactly the best fit
   // function we found.
   GrowableObjectArray& functions =
       GrowableObjectArray::Handle(GrowableObjectArray::New());
   FindCompiledFunctions(script,
                         func.token_pos(),
                         func.end_token_pos(),
                         &functions);
 
   if (functions.Length() > 0) {
     // One or more function object containing this breakpoint location
     // have already been compiled. We can resolve the breakpoint now.
     DeoptimizeWorld();
     func ^= functions.At(0);
     intptr_t breakpoint_pos =
         ResolveBreakpointPos(func, token_pos, last_token_pos);
     if (breakpoint_pos >= 0) {
-      SourceBreakpoint* bpt = GetSourceBreakpoint(script, breakpoint_pos);
+      BreakpointLocation* bpt = GetBreakpointLocation(script, breakpoint_pos);
       if (bpt != NULL) {
         // A source breakpoint for this location already exists.
         return bpt;
       }
-      bpt = new SourceBreakpoint(nextId(), script, token_pos, last_token_pos);
+      bpt = new BreakpointLocation(script, token_pos, last_token_pos);
       bpt->SetResolved(func, breakpoint_pos);
-      RegisterSourceBreakpoint(bpt);
+      RegisterBreakpointLocation(bpt);
 
       // Create code breakpoints for all compiled functions we found.
       const intptr_t num_functions = functions.Length();
       for (intptr_t i = 0; i < num_functions; i++) {
         func ^= functions.At(i);
         ASSERT(func.HasCode());
         MakeCodeBreakpointAt(func, bpt);
       }
-      bpt->Enable();
       if (FLAG_verbose_debug) {
         intptr_t line_number;
         script.GetTokenLocation(breakpoint_pos, &line_number, NULL);
         OS::Print("Resolved BP for "
                   "function '%s' at line %" Pd "\n",
                   func.ToFullyQualifiedCString(),
                   line_number);
       }
-      SignalBpResolved(bpt);
-      SendServiceBreakpointEvent(ServiceEvent::kBreakpointAdded, bpt);
       return bpt;
     }
   }
   // There is no compiled function at this token position.
   // Register an unresolved breakpoint.
   if (FLAG_verbose_debug && !func.IsNull()) {
     intptr_t line_number;
     script.GetTokenLocation(token_pos, &line_number, NULL);
     OS::Print("Registering pending breakpoint for "
               "uncompiled function '%s' at line %" Pd "\n",
               func.ToFullyQualifiedCString(),
               line_number);
   }
-  SourceBreakpoint* bpt = GetSourceBreakpoint(script, token_pos);
+  BreakpointLocation* bpt = GetBreakpointLocation(script, token_pos);
   if (bpt == NULL) {
-    bpt = new SourceBreakpoint(nextId(), script, token_pos, last_token_pos);
-    RegisterSourceBreakpoint(bpt);
-    SendServiceBreakpointEvent(ServiceEvent::kBreakpointAdded, bpt);
+    bpt = new BreakpointLocation(script, token_pos, last_token_pos);
+    RegisterBreakpointLocation(bpt);
   }
-  bpt->Enable();
   return bpt;
 }
 
 
 // Synchronize the enabled/disabled state of all code breakpoints
-// associated with the source breakpoint bpt.
-void Debugger::SyncBreakpoint(SourceBreakpoint* bpt) {
+// associated with the breakpoint location loc.
+void Debugger::SyncBreakpointLocation(BreakpointLocation* loc) {
+  bool any_enabled = loc->AnyEnabled();
+
   CodeBreakpoint* cbpt = code_breakpoints_;
   while (cbpt != NULL) {
-    if (bpt == cbpt->src_bpt()) {
-      if (bpt->IsEnabled()) {
+    if (loc == cbpt->bpt_location()) {
+      if (any_enabled) {
         cbpt->Enable();
       } else {
         cbpt->Disable();
       }
     }
     cbpt = cbpt->next();
   }
 }
 
 
 RawError* Debugger::OneTimeBreakAtEntry(const Function& target_function) {
   LongJumpScope jump;
   if (setjmp(*jump.Set()) == 0) {
-    SourceBreakpoint* bpt = SetBreakpointAtEntry(target_function);
-    if (bpt != NULL) {
-      bpt->SetIsOneShot();
-    }
+    SetBreakpointAtEntry(target_function, true);
     return Error::null();
   } else {
     return isolate_->object_store()->sticky_error();
   }
 }
 
 
-SourceBreakpoint* Debugger::SetBreakpointAtEntry(
-      const Function& target_function) {
+Breakpoint* Debugger::SetBreakpointAtEntry(const Function& target_function,
+                                           bool single_shot) {
   ASSERT(!target_function.IsNull());
   if (!target_function.is_debuggable()) {
     return NULL;
   }
   const Script& script = Script::Handle(target_function.script());
-  return SetBreakpoint(script,
-                       target_function.token_pos(),
-                       target_function.end_token_pos());
+  BreakpointLocation* bpt_location =
+      SetBreakpoint(script,
+                    target_function.token_pos(),
+                    target_function.end_token_pos());
+  if (single_shot) {
+    return bpt_location->AddSingleShot(this);
+  } else {
+    return bpt_location->AddRepeated(this);
+  }
 }
 
 
-SourceBreakpoint* Debugger::SetBreakpointAtLine(const String& script_url,
-                                                intptr_t line_number) {
+Breakpoint* Debugger::SetBreakpointAtActivation(
+    const Instance& closure) {
+  if (!closure.IsClosure()) {
+    return NULL;
+  }
+  const Function& func = Function::Handle(Closure::function(closure));
+  const Script& script = Script::Handle(func.script());
+  BreakpointLocation* bpt = SetBreakpoint(script,
+                                          func.token_pos(),
+                                          func.end_token_pos());
+  return bpt->AddPerClosure(this, closure);
+}
+
+
+Breakpoint* Debugger::SetBreakpointAtLine(const String& script_url,
+                                          intptr_t line_number) {
+  BreakpointLocation* loc = BreakpointLocationAtLine(script_url, line_number);
+  if (loc != NULL) {
+    return loc->AddRepeated(this);
+  }
+  return NULL;
+}
+
+
+BreakpointLocation* Debugger::BreakpointLocationAtLine(const String& script_url,
+                                                       intptr_t line_number) {
   Library& lib = Library::Handle(isolate_);
   Script& script = Script::Handle(isolate_);
   const GrowableObjectArray& libs =
       GrowableObjectArray::Handle(isolate_->object_store()->libraries());
   const GrowableObjectArray& scripts =
     GrowableObjectArray::Handle(isolate_, GrowableObjectArray::New());
   for (intptr_t i = 0; i < libs.Length(); i++) {
     lib ^= libs.At(i);
     script = lib.LookupScript(script_url);
     if (!script.IsNull()) {
       scripts.Add(script);
     }
   }
   if (scripts.Length() == 0) {
     // No script found with given url. Create a latent breakpoint which
     // will be set if the url is loaded later.
-    SourceBreakpoint* latent_bpt = GetLatentBreakpoint(script_url, line_number);
+    BreakpointLocation* latent_bpt = GetLatentBreakpoint(script_url,
+                                                         line_number);
     if (FLAG_verbose_debug) {
       OS::Print("Set latent breakpoint in url '%s' at line %" Pd "\n",
                 script_url.ToCString(),
                 line_number);
     }
     return latent_bpt;
   }
   if (scripts.Length() > 1) {
     if (FLAG_verbose_debug) {
       OS::Print("Multiple scripts match url '%s'\n", script_url.ToCString());
@@ skipping 12 matching lines @@
     return NULL;
   } else if (last_token_idx < 0) {
     // Line does not contain any tokens.
     if (FLAG_verbose_debug) {
       OS::Print("No executable code at line %" Pd " in '%s'\n",
                 line_number, script_url.ToCString());
     }
     return NULL;
   }
 
-  SourceBreakpoint* bpt = NULL;
+  BreakpointLocation* bpt = NULL;
   ASSERT(first_token_idx <= last_token_idx);
   while ((bpt == NULL) && (first_token_idx <= last_token_idx)) {
     bpt = SetBreakpoint(script, first_token_idx, last_token_idx);
     first_token_idx++;
   }
   if ((bpt == NULL) && FLAG_verbose_debug) {
     OS::Print("No executable code at line %" Pd " in '%s'\n",
                 line_number, script_url.ToCString());
   }
   return bpt;
@@ skipping 193 matching lines @@
       CollectLibraryFields(field_list, imported, prefix_name, false);
     }
   }
   return Array::MakeArray(field_list);
 }
 
 
 // static
 void Debugger::VisitObjectPointers(ObjectPointerVisitor* visitor) {
   ASSERT(visitor != NULL);
-  SourceBreakpoint* bpt = src_breakpoints_;
+  BreakpointLocation* bpt = breakpoint_locations_;
   while (bpt != NULL) {
     bpt->VisitObjectPointers(visitor);
     bpt = bpt->next();
   }
-  bpt = latent_breakpoints_;
+  bpt = latent_locations_;
   while (bpt != NULL) {
     bpt->VisitObjectPointers(visitor);
     bpt = bpt->next();
   }
   CodeBreakpoint* cbpt = code_breakpoints_;
   while (cbpt != NULL) {
     cbpt->VisitObjectPointers(visitor);
     cbpt = cbpt->next();
   }
 }
@@ skipping 62 matching lines @@
   if (ServiceIsolate::IsRunning()) {
     return true;
   }
   const Class& cls = Class::Handle(func.Owner());
   const Library& lib = Library::Handle(cls.library());
   return lib.IsDebuggable();
 }
 
 
 void Debugger::SignalPausedEvent(ActivationFrame* top_frame,
-                                 SourceBreakpoint* bpt) {
+                                 Breakpoint* bpt) {
   resume_action_ = kContinue;
   stepping_fp_ = 0;
   isolate_->set_single_step(false);
   ASSERT(!IsPaused());
   ASSERT(obj_cache_ == NULL);
-  if ((bpt != NULL) && bpt->IsOneShot()) {
+  if ((bpt != NULL) && bpt->IsSingleShot())  {
     RemoveBreakpoint(bpt->id());
     bpt = NULL;
   }
   DebuggerEvent event(isolate_, DebuggerEvent::kBreakpointReached);
   event.set_top_frame(top_frame);
   event.set_breakpoint(bpt);
   Pause(&event);
 }
 
 
@@ skipping 61 matching lines @@
   // We ignore this breakpoint when the VM is executing code invoked
   // by the debugger to evaluate variables values, or when we see a nested
   // breakpoint or exception event.
   if (ignore_breakpoints_ || IsPaused() || !HasEventHandler()) {
     return;
   }
   DebuggerStackTrace* stack_trace = CollectStackTrace();
   ASSERT(stack_trace->Length() > 0);
   ActivationFrame* top_frame = stack_trace->FrameAt(0);
   ASSERT(top_frame != NULL);
-  CodeBreakpoint* bpt = GetCodeBreakpoint(top_frame->pc());
-  ASSERT(bpt != NULL);
+  CodeBreakpoint* cbpt = GetCodeBreakpoint(top_frame->pc());
+  ASSERT(cbpt != NULL);
+
+  BreakpointLocation* bpt_location = cbpt->bpt_location_;
+  Breakpoint* bpt_hit = NULL;
+
+  // There may be more than one applicable breakpoint at this location, but we
+  // will report only one as reached. If there is a single-shot breakpoint, we
+  // favor it; then a closure-specific breakpoint ; then an general breakpoint.
+  if (bpt_location != NULL) {
+    Breakpoint* bpt = bpt_location->breakpoints();
+    while (bpt != NULL) {
+      if (bpt->IsSingleShot()) {
+        bpt_hit = bpt;
+        break;
+      }
+      bpt = bpt->next();
+    }
+
+    if (bpt_hit == NULL) {
+      bpt = bpt_location->breakpoints();
+      while (bpt != NULL) {
+        if (bpt->IsPerClosure()) {
+          Object& closure = Object::Handle(top_frame->GetClosure());
+          ASSERT(closure.IsInstance());
+          ASSERT(Instance::Cast(closure).IsClosure());
+          if (closure.raw() == bpt->closure()) {
+            bpt_hit = bpt;
+            break;
+          }
+        }
+        bpt = bpt->next();
+      }
+    }
+
+    if (bpt_hit == NULL) {
+      bpt = bpt_location->breakpoints();
+      while (bpt != NULL) {
+        if (bpt->IsRepeated()) {
+          bpt_hit = bpt;
+          break;
+        }
+        bpt = bpt->next();
+      }
+    }
+  }
+
+  if (bpt_hit == NULL) {
+    return;
+  }
 
   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(),
+              cbpt->IsInternal() ? "internal" : "user",
+              String::Handle(cbpt->SourceUrl()).ToCString(),
+              cbpt->LineNumber(),
+              cbpt->token_pos(),
               top_frame->pc());
   }
 
   ASSERT(stack_trace_ == NULL);
   stack_trace_ = stack_trace;
-  SignalPausedEvent(top_frame, bpt->src_bpt_);
+  SignalPausedEvent(top_frame, bpt_hit);
   HandleSteppingRequest(stack_trace_);
   stack_trace_ = NULL;
-  if (bpt->IsInternal()) {
+  if (cbpt->IsInternal()) {
     RemoveInternalBreakpoints();
   }
 }
 
 
 void Debugger::BreakHere(const String& msg) {
   // We ignore this breakpoint when the VM is executing code invoked
   // by the debugger to evaluate variables values, or when we see a nested
   // breakpoint or exception event.
   if (ignore_breakpoints_ || IsPaused() || !HasEventHandler()) {
@@ skipping 65 matching lines @@
         (token_pos <= closure.end_token_pos()) &&
         (closure.script() == outer_origin.raw())) {
       SelectBestFit(&best_fit, &closure);
     }
   }
   return best_fit.raw();
 }
 
 
 void Debugger::NotifyCompilation(const Function& func) {
-  if (src_breakpoints_ == NULL) {
+  if (breakpoint_locations_ == NULL) {
     // Return with minimal overhead if there are no breakpoints.
     return;
   }
   if (!func.is_debuggable()) {
     // Nothing to do if the function is not debuggable. If there is
     // a pending breakpoint in an inner function (that is debuggable),
     // we'll resolve the breakpoint when the inner function is compiled.
     return;
   }
   // Iterate over all source breakpoints to check whether breakpoints
   // need to be set in the newly compiled function.
   Script& script = Script::Handle(isolate_);
-  for (SourceBreakpoint* bpt = src_breakpoints_;
-      bpt != NULL;
-      bpt = bpt->next()) {
-    script = bpt->script();
-    if (FunctionContains(func, script, bpt->token_pos())) {
+  for (BreakpointLocation* loc = breakpoint_locations_;
+      loc != NULL;
+      loc = loc->next()) {
+    script = loc->script();
+    if (FunctionContains(func, script, loc->token_pos())) {
       Function& inner_function = Function::Handle(isolate_);
-      inner_function = FindInnermostClosure(func, bpt->token_pos());
+      inner_function = FindInnermostClosure(func, loc->token_pos());
       if (!inner_function.IsNull()) {
         // The local function of a function we just compiled cannot
         // be compiled already.
         ASSERT(!inner_function.HasCode());
         if (FLAG_verbose_debug) {
           OS::Print("Pending BP remains unresolved in inner function '%s'\n",
                     inner_function.ToFullyQualifiedCString());
         }
         continue;
       }
 
       // TODO(hausner): What should we do if function is optimized?
       // Can we deoptimize the function?
       ASSERT(!func.HasOptimizedCode());
 
       // There is no local function within func that contains the
       // breakpoint token position. Resolve the breakpoint if necessary
       // and set the code breakpoints.
-      if (!bpt->IsResolved()) {
+      if (!loc->IsResolved()) {
         // Resolve source breakpoint in the newly compiled function.
         intptr_t bp_pos =
-            ResolveBreakpointPos(func, bpt->token_pos(), bpt->end_token_pos());
+            ResolveBreakpointPos(func, loc->token_pos(), loc->end_token_pos());
         if (bp_pos < 0) {
           if (FLAG_verbose_debug) {
             OS::Print("Failed resolving breakpoint for function '%s'\n",
                       String::Handle(func.name()).ToCString());
           }
           continue;
         }
-        intptr_t requested_pos = bpt->token_pos();
-        intptr_t requested_end_pos = bpt->end_token_pos();
-        bpt->SetResolved(func, bp_pos);
-        if (FLAG_verbose_debug) {
-          OS::Print("Resolved BP %" Pd " to pos %" Pd ", line %" Pd ", "
-                    "function '%s' (requested range %" Pd "-%" Pd ")\n",
+        intptr_t requested_pos = loc->token_pos();
+        intptr_t requested_end_pos = loc->end_token_pos();
+        loc->SetResolved(func, bp_pos);
+        Breakpoint* bpt = loc->breakpoints();
+        while (bpt != NULL) {
+          if (FLAG_verbose_debug) {
+            OS::Print("Resolved BP %" Pd " to pos %" Pd ", line %" Pd ", "
+                      "function '%s' (requested range %" Pd "-%" Pd ")\n",
+                      bpt->id(),
+                      loc->token_pos(),
+                      loc->LineNumber(),
+                      func.ToFullyQualifiedCString(),
+                      requested_pos,
+                      requested_end_pos);
+          }
+          SignalBpResolved(bpt);
+          SendServiceBreakpointEvent(ServiceEvent::kBreakpointResolved, bpt);
+          bpt = bpt->next();
+        }
+      }
+      ASSERT(loc->IsResolved());
+      if (FLAG_verbose_debug) {
+        Breakpoint* bpt = loc->breakpoints();
+        while (bpt != NULL) {
+          OS::Print("Setting breakpoint %" Pd " at line %" Pd " for %s '%s'\n",
                     bpt->id(),
-                    bpt->token_pos(),
-                    bpt->LineNumber(),
-                    func.ToFullyQualifiedCString(),
-                    requested_pos,
-                    requested_end_pos);
+                    loc->LineNumber(),
+                    func.IsClosureFunction() ? "closure" : "function",
+                    String::Handle(func.name()).ToCString());
+          bpt = bpt->next();
         }
-        SignalBpResolved(bpt);
-        SendServiceBreakpointEvent(ServiceEvent::kBreakpointResolved, bpt);
       }
-      ASSERT(bpt->IsResolved());
-      if (FLAG_verbose_debug) {
-        OS::Print("Setting breakpoint %" Pd " at line %" Pd " for %s '%s'\n",
-                  bpt->id(),
-                  bpt->LineNumber(),
-                  func.IsClosureFunction() ? "closure" : "function",
-                  String::Handle(func.name()).ToCString());
-      }
-      MakeCodeBreakpointAt(func, bpt);
+      MakeCodeBreakpointAt(func, loc);
     }
   }
 }
 
 
 void Debugger::NotifyDoneLoading() {
-  if (latent_breakpoints_ == NULL) {
+  if (latent_locations_ == NULL) {
     // Common, fast path.
     return;
   }
   Library& lib = Library::Handle(isolate_);
   Script& script = Script::Handle(isolate_);
   String& url = String::Handle(isolate_);
-  SourceBreakpoint* bpt = latent_breakpoints_;
-  SourceBreakpoint* prev_bpt = NULL;
+  BreakpointLocation* loc = latent_locations_;
+  BreakpointLocation* prev_loc = NULL;
   const GrowableObjectArray& libs =
       GrowableObjectArray::Handle(isolate_->object_store()->libraries());
-  while (bpt != NULL) {
-    url = bpt->url();
+  while (loc != NULL) {
+    url = loc->url();
     bool found_match = false;
     for (intptr_t i = 0; i < libs.Length(); i++) {
       lib ^= libs.At(i);
       script = lib.LookupScript(url);
       if (!script.IsNull()) {
         // Found a script with matching url for this latent breakpoint.
         // Unlink the latent breakpoint from the list.
         found_match = true;
-        SourceBreakpoint* matched_bpt = bpt;
-        bpt = bpt->next();
-        if (prev_bpt == NULL) {
-          latent_breakpoints_ = bpt;
+        BreakpointLocation* matched_loc = loc;
+        loc = loc->next();
+        if (prev_loc == NULL) {
+          latent_locations_ = loc;
         } else {
-          prev_bpt->set_next(bpt);
+          prev_loc->set_next(loc);
         }
         // Now find the token range at the requested line and make a
         // new unresolved source breakpoint.
-        intptr_t line_number = matched_bpt->LineNumber();
+        intptr_t line_number = matched_loc->LineNumber();
         ASSERT(line_number >= 0);
         intptr_t first_token_pos, last_token_pos;
         script.TokenRangeAtLine(line_number, &first_token_pos, &last_token_pos);
         if ((first_token_pos < 0) ||
             (last_token_pos < 0)) {
           // Script does not contain the given line number or there are no
           // tokens on the line. Drop the breakpoint silently.
-          if (FLAG_verbose_debug) {
-            OS::Print("No code found at line %" Pd ": "
-                      "dropping latent breakpoint %" Pd " in '%s'\n",
-                      line_number,
-                      matched_bpt->id(),
-                      url.ToCString());
+          Breakpoint* bpt = matched_loc->breakpoints();
+          while (bpt != NULL) {
+            if (FLAG_verbose_debug) {
+              OS::Print("No code found at line %" Pd ": "
+                        "dropping latent breakpoint %" Pd " in '%s'\n",
+                        line_number,
+                        bpt->id(),
+                        url.ToCString());
+            }
+            Breakpoint* prev = bpt;
+            bpt = bpt->next();
+            delete prev;
           }
-          delete matched_bpt;
+          delete matched_loc;
         } else {
           // We don't expect to already have a breakpoint for this location.
           // If there is one, assert in debug build but silently drop
           // the latent breakpoint in release build.
-          SourceBreakpoint* existing_bpt =
-              GetSourceBreakpoint(script, first_token_pos);
-          ASSERT(existing_bpt == NULL);
-          if (existing_bpt == NULL) {
+          BreakpointLocation* existing_loc =
+              GetBreakpointLocation(script, first_token_pos);
+          ASSERT(existing_loc == NULL);
+          if (existing_loc == NULL) {
             // Create and register a new source breakpoint for the
             // latent breakpoint.
-            SourceBreakpoint* unresolved_bpt =
-                new SourceBreakpoint(matched_bpt->id(),
-                                     script,
-                                     first_token_pos,
-                                     last_token_pos);
-            RegisterSourceBreakpoint(unresolved_bpt);
-            unresolved_bpt->Enable();
-            if (FLAG_verbose_debug) {
-              OS::Print("Converted latent breakpoint "
-                        "%" Pd " in '%s' at line %" Pd "\n",
-                        matched_bpt->id(),
-                        url.ToCString(),
-                        line_number);
+            BreakpointLocation* unresolved_loc =
+                new BreakpointLocation(script,
+                                       first_token_pos,
+                                       last_token_pos);
+            RegisterBreakpointLocation(unresolved_loc);
+
+            // Move breakpoints over.
+            Breakpoint* bpt = matched_loc->breakpoints();
+            unresolved_loc->set_breakpoints(bpt);
+            matched_loc->set_breakpoints(NULL);
+            while (bpt != NULL) {
+              bpt->set_bpt_location(unresolved_loc);
+              if (FLAG_verbose_debug) {
+                OS::Print("Converted latent breakpoint "
+                          "%" Pd " in '%s' at line %" Pd "\n",
+                          bpt->id(),
+                          url.ToCString(),
+                          line_number);
+              }
+              bpt = bpt->next();
             }
+            SyncBreakpointLocation(unresolved_loc);
           }
-          delete matched_bpt;
+          delete matched_loc;
           // Break out of the iteration over loaded libraries. If the
           // same url has been loaded into more than one library, we
           // only set a breakpoint in the first one.
           // TODO(hausner): There is one possible pitfall here.
           // If the user sets a latent breakpoint using a partial url that
           // ends up matching more than one script, the breakpoint might
           // get set in the wrong script.
           // It would be better if we could warn the user if multiple
           // scripts are matching.
           break;
         }
       }
     }
     if (!found_match) {
       // No matching url found in any of the libraries.
       if (FLAG_verbose_debug) {
-        OS::Print("No match found for latent breakpoint id "
-                  "%" Pd " with url '%s'\n",
-                  bpt->id(),
-                  url.ToCString());
+        Breakpoint* bpt = loc->breakpoints();
+        while (bpt != NULL) {
+          OS::Print("No match found for latent breakpoint id "
+                    "%" Pd " with url '%s'\n",
+                    bpt->id(),
+                    url.ToCString());
+          bpt = bpt->next();
+        }
       }
-      bpt = bpt->next();
+      loc = loc->next();
     }
   }
 }
 
 
 // TODO(hausner): Could potentially make this faster by checking
 // whether the call target at pc is a debugger stub.
 bool Debugger::HasActiveBreakpoint(uword pc) {
   CodeBreakpoint* bpt = GetCodeBreakpoint(pc);
   return (bpt != NULL) && (bpt->IsEnabled());
@@ skipping 18 matching lines @@
     return bpt->OrigStubAddress();
   }
   UNREACHABLE();
   return 0L;
 }
 
 
 // Remove and delete the source breakpoint bpt and its associated
 // code breakpoints.
 void Debugger::RemoveBreakpoint(intptr_t bp_id) {
-  SourceBreakpoint* prev_bpt = NULL;
-  SourceBreakpoint* curr_bpt = src_breakpoints_;
-  while (curr_bpt != NULL) {
-    if (curr_bpt->id() == bp_id) {
-      if (prev_bpt == NULL) {
-        src_breakpoints_ = src_breakpoints_->next();
+  BreakpointLocation* prev_loc = NULL;
+  BreakpointLocation* curr_loc = breakpoint_locations_;
+  while (curr_loc != NULL) {
+    Breakpoint* prev_bpt = NULL;
+    Breakpoint* curr_bpt = curr_loc->breakpoints();
+    while (curr_bpt != NULL) {
+      if (curr_bpt->id() == bp_id) {
+        if (prev_bpt == NULL) {
+          curr_loc->set_breakpoints(curr_bpt->next());
+        } else {
+          prev_bpt->set_next(curr_bpt->next());
+        }
+
+        SendServiceBreakpointEvent(ServiceEvent::kBreakpointRemoved, curr_bpt);
+
+        // Remove references from the current debugger pause event.
+        if (pause_event_ != NULL &&
+            pause_event_->type() == DebuggerEvent::kBreakpointReached &&
+            pause_event_->breakpoint() == curr_bpt) {
+          pause_event_->set_breakpoint(NULL);
+        }
+        return;
+      }
+
+      prev_bpt = curr_bpt;
+      curr_bpt = curr_bpt->next();
+    }
+
+    if (curr_loc->breakpoints() == NULL) {
+      if (prev_loc == NULL) {
+        breakpoint_locations_ = breakpoint_locations_->next();
       } else {
-        prev_bpt->set_next(curr_bpt->next());
+        prev_loc->set_next(curr_loc->next());
       }
-      SendServiceBreakpointEvent(ServiceEvent::kBreakpointRemoved, curr_bpt);
 
       // Remove references from code breakpoints to this source breakpoint,
       // and disable the code breakpoints.
-      UnlinkCodeBreakpoints(curr_bpt);
-      delete curr_bpt;
+      UnlinkCodeBreakpoints(curr_loc);
+      delete curr_loc;
+    }
 
-      // Remove references from the current debugger pause event.
-      if (pause_event_ != NULL &&
-          pause_event_->type() == DebuggerEvent::kBreakpointReached &&
-          pause_event_->breakpoint() == curr_bpt) {
-        pause_event_->set_breakpoint(NULL);
-      }
-      return;
-    }
-    prev_bpt = curr_bpt;
-    curr_bpt = curr_bpt->next();
+    prev_loc = curr_loc;
+    curr_loc = curr_loc->next();
   }
   // bpt is not a registered breakpoint, nothing to do.
 }
 
 
 // Turn code breakpoints associated with the given source breakpoint into
 // internal breakpoints. They will later be deleted when control
 // returns from the user-defined breakpoint callback. Also, disable the
 // breakpoint so it no longer fires if it should be hit before it gets
 // deleted.
-void Debugger::UnlinkCodeBreakpoints(SourceBreakpoint* src_bpt) {
-  ASSERT(src_bpt != NULL);
+void Debugger::UnlinkCodeBreakpoints(BreakpointLocation* bpt_location) {
+  ASSERT(bpt_location != NULL);
   CodeBreakpoint* curr_bpt = code_breakpoints_;
   while (curr_bpt != NULL) {
-    if (curr_bpt->src_bpt() == src_bpt) {
+    if (curr_bpt->bpt_location() == bpt_location) {
       curr_bpt->Disable();
-      curr_bpt->set_src_bpt(NULL);
+      curr_bpt->set_bpt_location(NULL);
     }
     curr_bpt = curr_bpt->next();
   }
 }
 
 
 // Remove and delete internal breakpoints, i.e. breakpoints that
 // are not associated with a source breakpoint.
 void Debugger::RemoveInternalBreakpoints() {
   CodeBreakpoint* prev_bpt = NULL;
   CodeBreakpoint* curr_bpt = code_breakpoints_;
   while (curr_bpt != NULL) {
-    if (curr_bpt->src_bpt() == NULL) {
+    if (curr_bpt->bpt_location() == NULL) {
       if (prev_bpt == NULL) {
         code_breakpoints_ = code_breakpoints_->next();
       } else {
         prev_bpt->set_next(curr_bpt->next());
       }
       CodeBreakpoint* temp_bpt = curr_bpt;
       curr_bpt = curr_bpt->next();
       temp_bpt->Disable();
       delete temp_bpt;
     } else {
       prev_bpt = curr_bpt;
       curr_bpt = curr_bpt->next();
     }
   }
 }
 
 
-SourceBreakpoint* Debugger::GetSourceBreakpoint(const Script& script,
-                                                intptr_t token_pos) {
-  SourceBreakpoint* bpt = src_breakpoints_;
+BreakpointLocation* Debugger::GetBreakpointLocation(const Script& script,
+                                                    intptr_t token_pos) {
+  BreakpointLocation* bpt = breakpoint_locations_;
   while (bpt != NULL) {
     if ((bpt->script_ == script.raw()) && (bpt->token_pos_ == token_pos)) {
       return bpt;
     }
     bpt = bpt->next();
   }
   return NULL;
 }
 
 
-SourceBreakpoint* Debugger::GetBreakpointById(intptr_t id) {
-  SourceBreakpoint* bpt = src_breakpoints_;
-  while (bpt != NULL) {
-    if (bpt->id() == id) {
-      return bpt;
+Breakpoint* Debugger::GetBreakpointById(intptr_t id) {
+  BreakpointLocation* loc = breakpoint_locations_;
+  while (loc != NULL) {
+    Breakpoint* bpt = loc->breakpoints();
+    while (bpt != NULL) {
+      if (bpt->id() == id) {
+        return bpt;
+      }
+      bpt = bpt->next();
     }
-    bpt = bpt->next();
+    loc = loc->next();
   }
   return NULL;
 }
 
 
-SourceBreakpoint* Debugger::GetLatentBreakpoint(const String& url,
-                                                intptr_t line) {
-  SourceBreakpoint* bpt = latent_breakpoints_;
+BreakpointLocation* Debugger::GetLatentBreakpoint(const String& url,
+                                                  intptr_t line) {
+  BreakpointLocation* bpt = latent_locations_;
   String& bpt_url = String::Handle(isolate_);
   while (bpt != NULL) {
     bpt_url = bpt->url();
     if (bpt_url.Equals(url) && (bpt->LineNumber() == line)) {
       return bpt;
     }
     bpt = bpt->next();
   }
   // No breakpint for this url and line requested. Allocate new one.
-  bpt = new SourceBreakpoint(nextId(), url, line);
-  bpt->set_next(latent_breakpoints_);
-  latent_breakpoints_ = bpt;
+  bpt = new BreakpointLocation(url, line);
+  bpt->set_next(latent_locations_);
+  latent_locations_ = bpt;
   return bpt;
 }
 
 
-void Debugger::RegisterSourceBreakpoint(SourceBreakpoint* bpt) {
+void Debugger::RegisterBreakpointLocation(BreakpointLocation* bpt) {
   ASSERT(bpt->next() == NULL);
-  bpt->set_next(src_breakpoints_);
-  src_breakpoints_ = bpt;
+  bpt->set_next(breakpoint_locations_);
+  breakpoint_locations_ = bpt;
 }
 
 
 void Debugger::RegisterCodeBreakpoint(CodeBreakpoint* bpt) {
   ASSERT(bpt->next() == NULL);
   bpt->set_next(code_breakpoints_);
   code_breakpoints_ = bpt;
 }
 
 }  // namespace dart