[debug] implement intuitive semantics for stepping over await call.

src/ia32/builtins-ia32.cc

 // Copyright 2012 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.
 
 #if V8_TARGET_ARCH_IA32
 
 #include "src/code-factory.h"
 #include "src/codegen.h"
 #include "src/deoptimizer.h"
 #include "src/full-codegen/full-codegen.h"
@@ skipping 389 matching lines @@
                       kDontSaveFPRegs);
 
   // Store resume mode into generator object.
   __ mov(FieldOperand(ebx, JSGeneratorObject::kResumeModeOffset), edx);
 
   // Load suspended function and context.
   __ mov(esi, FieldOperand(ebx, JSGeneratorObject::kContextOffset));
   __ mov(edi, FieldOperand(ebx, JSGeneratorObject::kFunctionOffset));
 
   // Flood function if we are stepping.
-  Label skip_flooding;
+  Label prepare_step_in_if_stepping, prepare_step_in_suspended_generator;
+  Label stepping_prepared;
   ExternalReference step_in_enabled =
       ExternalReference::debug_step_in_enabled_address(masm->isolate());
   __ cmpb(Operand::StaticVariable(step_in_enabled), Immediate(0));
-  __ j(equal, &skip_flooding);
-  {
-    FrameScope scope(masm, StackFrame::INTERNAL);
-    __ Push(ebx);
-    __ Push(edx);
-    __ Push(edi);
-    __ CallRuntime(Runtime::kDebugPrepareStepInIfStepping);
-    __ Pop(edx);
-    __ Pop(ebx);
-    __ mov(edi, FieldOperand(ebx, JSGeneratorObject::kFunctionOffset));
-  }
-  __ bind(&skip_flooding);
+  __ j(not_equal, &prepare_step_in_if_stepping);
+
+  // Flood function if we need to continue stepping in the suspended generator.
+  ExternalReference debug_suspended_generator =
+      ExternalReference::debug_suspended_generator_address(masm->isolate());
+  __ cmp(ebx, Operand::StaticVariable(debug_suspended_generator));
+  __ j(equal, &prepare_step_in_suspended_generator);
+  __ bind(&stepping_prepared);
 
   // Pop return address.
   __ PopReturnAddressTo(eax);
 
   // Push receiver.
   __ Push(FieldOperand(ebx, JSGeneratorObject::kReceiverOffset));
 
   // ----------- S t a t e -------------
   //  -- eax    : return address
   //  -- ebx    : the JSGeneratorObject to resume
@@ skipping 75 matching lines @@
     __ mov(edx, FieldOperand(edi, JSFunction::kSharedFunctionInfoOffset));
     __ mov(edx, FieldOperand(edx, SharedFunctionInfo::kCodeOffset));
     __ mov(ecx, FieldOperand(ebx, JSGeneratorObject::kContinuationOffset));
     __ SmiUntag(ecx);
     __ lea(edx, FieldOperand(edx, ecx, times_1, Code::kHeaderSize));
     __ mov(FieldOperand(ebx, JSGeneratorObject::kContinuationOffset),
            Immediate(Smi::FromInt(JSGeneratorObject::kGeneratorExecuting)));
     __ mov(eax, ebx);  // Continuation expects generator object in eax.
     __ jmp(edx);
   }
+
+  __ bind(&prepare_step_in_if_stepping);
+  {
+    FrameScope scope(masm, StackFrame::INTERNAL);
+    __ Push(ebx);
+    __ Push(edx);
+    __ Push(edi);
+    __ CallRuntime(Runtime::kDebugPrepareStepInIfStepping);
+    __ Pop(edx);
+    __ Pop(ebx);
+    __ mov(edi, FieldOperand(ebx, JSGeneratorObject::kFunctionOffset));
+  }
+  __ jmp(&stepping_prepared);
+
+  __ bind(&prepare_step_in_suspended_generator);
+  {
+    FrameScope scope(masm, StackFrame::INTERNAL);
+    __ Push(ebx);
+    __ Push(edx);
+    __ CallRuntime(Runtime::kDebugPrepareStepInSuspendedGenerator);
+    __ Pop(edx);
+    __ Pop(ebx);
+    __ mov(edi, FieldOperand(ebx, JSGeneratorObject::kFunctionOffset));
+  }
+  __ jmp(&stepping_prepared);
 }
 
 static void LeaveInterpreterFrame(MacroAssembler* masm, Register scratch1,
                                   Register scratch2) {
   Register args_count = scratch1;
   Register return_pc = scratch2;
 
   // Get the arguments + reciever count.
   __ mov(args_count,
          Operand(ebp, InterpreterFrameConstants::kBytecodeArrayFromFp));
@@ skipping 2329 matching lines @@
   // And "return" to the OSR entry point of the function.
   __ ret(0);
 }
 
 
 #undef __
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_IA32