Revert of Debugger: deduplicate shared function info when setting script break points. (patchset #4 id:60001 of https://codereview.chromium.org/998253005/)

Reason for revert:
Code caching failures.

Original issue's description:
> Debugger: deduplicate shared function info when setting script break points.
>
> Also fix Debug.showBreakPoints for multiple break points at the same location.
>
> BUG=v8:3960
> LOG=N
>
> Committed: https://crrev.com/73b17a71a22564c0b66d9aa7c00948c748f5b290
> Cr-Commit-Position: refs/heads/master@{#27444}

TBR=mstarzinger@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:3960

Review URL: https://codereview.chromium.org/999273003

Cr-Commit-Position: refs/heads/master@{#27448}

src/compiler.cc

@@ -1426,7 +1426,7 @@ Handle<SharedFunctionInfo> Compiler::BuildFunctionInfo(
   result->set_is_toplevel(false);
 
   RecordFunctionCompilation(Logger::FUNCTION_TAG, &info, result);
-  result->set_allows_lazy_compilation(literal->AllowsLazyCompilation());
+  result->set_allows_lazy_compilation(allow_lazy);
   result->set_allows_lazy_compilation_without_context(allow_lazy_without_ctx);
 
   // Set the expected number of properties for instances and return

src/debug.cc

@@ -1506,22 +1506,23 @@ Handle<Object> Debug::GetSourceBreakLocations(
   Handle<FixedArray> locations =
       isolate->factory()->NewFixedArray(debug_info->GetBreakPointCount());
   int count = 0;
-  for (int i = 0; i < debug_info->break_points()->length(); ++i) {
+  for (int i = 0; i < debug_info->break_points()->length(); i++) {
     if (!debug_info->break_points()->get(i)->IsUndefined()) {
       BreakPointInfo* break_point_info =
           BreakPointInfo::cast(debug_info->break_points()->get(i));
-      int break_points = break_point_info->GetBreakPointCount();
-      if (break_points == 0) continue;
-      Smi* position = NULL;
-      switch (position_alignment) {
-        case STATEMENT_ALIGNED:
-          position = break_point_info->statement_position();
-          break;
-        case BREAK_POSITION_ALIGNED:
-          position = break_point_info->source_position();
-          break;
+      if (break_point_info->GetBreakPointCount() > 0) {
+        Smi* position = NULL;
+        switch (position_alignment) {
+          case STATEMENT_ALIGNED:
+            position = break_point_info->statement_position();
+            break;
+          case BREAK_POSITION_ALIGNED:
+            position = break_point_info->source_position();
+            break;
+        }
+
+        locations->set(count++, position);
       }
-      for (int j = 0; j < break_points; ++j) locations->set(count++, position);
     }
   }
   return locations;
@@ -1821,6 +1822,7 @@ static void RecompileAndRelocateSuspendedGenerators(
 static bool SkipSharedFunctionInfo(SharedFunctionInfo* shared,
                                    Object* active_code_marker) {
   if (!shared->allows_lazy_compilation()) return true;
+  if (!shared->script()->IsScript()) return true;
   Object* script = shared->script();
   if (!script->IsScript()) return true;
   if (Script::cast(script)->type()->value() == Script::TYPE_NATIVE) return true;
@@ -2101,21 +2103,6 @@ Handle<Object> Debug::FindSharedFunctionInfoInScript(Handle<Script> script,
     }
   }  // End while loop.
 
-  // JSFunctions from the same literal may not have the same shared function
-  // info. Find those JSFunctions and deduplicate the shared function info.
-  HeapIterator iterator(heap, FLAG_lazy ? HeapIterator::kNoFiltering
-                                        : HeapIterator::kFilterUnreachable);
-  for (HeapObject* obj = iterator.next(); obj != NULL; obj = iterator.next()) {
-    if (!obj->IsJSFunction()) continue;
-    JSFunction* function = JSFunction::cast(obj);
-    SharedFunctionInfo* shared = function->shared();
-    if (shared != *target && shared->script() == target->script() &&
-        shared->start_position_and_type() ==
-            target->start_position_and_type()) {
-      function->set_shared(*target);
-    }
-  }
-
   return target;
 }
 

src/liveedit.cc

@@ -1222,7 +1222,6 @@ void LiveEdit::SetFunctionScript(Handle<JSValue> function_wrapper,
       UnwrapSharedFunctionInfoFromJSValue(function_wrapper);
   CHECK(script_handle->IsScript() || script_handle->IsUndefined());
   shared_info->set_script(*script_handle);
-  shared_info->DisableOptimization(kLiveEdit);
 
   function_wrapper->GetIsolate()->compilation_cache()->Remove(shared_info);
 }

src/runtime/runtime-debug.cc

@@ -2685,15 +2685,6 @@ RUNTIME_FUNCTION(Runtime_ExecuteInDebugContext) {
 }
 
 
-RUNTIME_FUNCTION(Runtime_GetDebugContext) {
-  HandleScope scope(isolate);
-  DCHECK(args.length() == 0);
-  Handle<Context> context = isolate->debug()->GetDebugContext();
-  context->set_security_token(isolate->native_context()->security_token());
-  return context->global_proxy();
-}
-
-
 // Performs a GC.
 // Presently, it only does a full GC.
 RUNTIME_FUNCTION(Runtime_CollectGarbage) {

src/runtime/runtime.h

@@ -578,7 +578,6 @@ namespace internal {
   F(LiveEditRestartFrame, 2, 1)                     \
   F(GetFunctionCodePositionFromSource, 2, 1)        \
   F(ExecuteInDebugContext, 2, 1)                    \
-  F(GetDebugContext, 0, 1)                          \
                                                     \
   F(SetFlags, 1, 1)                                 \
   F(CollectGarbage, 1, 1)                           \

test/mjsunit/debug-liveedit-2.js

@@ -25,7 +25,7 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-// Flags: --expose-debug-as debug --noalways-opt
+// Flags: --expose-debug-as debug
 // Get the Debug object exposed from the debug context global object.
 
 

test/mjsunit/debug-liveedit-4.js

@@ -25,7 +25,7 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-// Flags: --expose-debug-as debug --noalways-opt
+// Flags: --expose-debug-as debug
 // Get the Debug object exposed from the debug context global object.
 
 // In this test case we edit a script so that techincally function text

test/mjsunit/regress/regress-3960.js

@@ -1,36 +0,0 @@
-// Copyright 2015 the V8 project authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-// Flags: --allow-natives-syntax
-
-// Test that setting break point is works correctly when the debugger is
-// activated late, which leads to duplicate shared function infos.
-
-(function() {
-  var Debug = %GetDebugContext().Debug;
-
-  function listener(event, exec_state, event_data, data) {
-    if (event != Debug.DebugEvent.Break) return;
-    try {
-      assertTrue(/foo/.test(exec_state.frame(0).sourceLineText()));
-      break_count++;
-    } catch (e) {
-      exception = e;
-    }
-  }
-
-  for (var i = 0; i < 3; i++) {
-    var foo = function() { a = 1; }
-    var exception = null;
-    var break_count = 0;
-    Debug.setListener(listener);
-    if (i < 2) Debug.setBreakPoint(foo, 0, 0);
-    assertTrue(/\[B\d\]a = 1/.test(Debug.showBreakPoints(foo)));
-    foo();
-    assertEquals(1, break_count);
-    assertNull(exception);
-  }
-
-  Debug.setListener(null);
-})();