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

src/arm/builtins-arm.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_ARM
 
 #include "src/codegen.h"
 #include "src/debug/debug.h"
 #include "src/deoptimizer.h"
 #include "src/full-codegen/full-codegen.h"
@@ skipping 702 matching lines @@
                       kLRHasNotBeenSaved, kDontSaveFPRegs);
 
   // Store resume mode into generator object.
   __ str(r2, FieldMemOperand(r1, JSGeneratorObject::kResumeModeOffset));
 
   // Load suspended function and context.
   __ ldr(cp, FieldMemOperand(r1, JSGeneratorObject::kContextOffset));
   __ ldr(r4, FieldMemOperand(r1, 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());
   __ mov(ip, Operand(step_in_enabled));
   __ ldrb(ip, MemOperand(ip));
   __ cmp(ip, Operand(0));
-  __ b(eq, &skip_flooding);
-  {
-    FrameAndConstantPoolScope scope(masm, StackFrame::INTERNAL);
-    __ Push(r1, r2, r4);
-    __ CallRuntime(Runtime::kDebugPrepareStepInIfStepping);
-    __ Pop(r1, r2);
-    __ ldr(r4, FieldMemOperand(r1, JSGeneratorObject::kFunctionOffset));
-  }
-  __ bind(&skip_flooding);
+  __ b(ne, &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());
+  __ mov(ip, Operand(debug_suspended_generator));
+  __ ldr(ip, MemOperand(ip));
+  __ cmp(ip, Operand(r1));
+  __ b(eq, &prepare_step_in_suspended_generator);
+  __ bind(&stepping_prepared);
 
   // Push receiver.
   __ ldr(ip, FieldMemOperand(r1, JSGeneratorObject::kReceiverOffset));
   __ Push(ip);
 
   // ----------- S t a t e -------------
   //  -- r1    : the JSGeneratorObject to resume
   //  -- r2    : the resume mode (tagged)
   //  -- r4    : generator function
   //  -- cp    : generator context
@@ skipping 75 matching lines @@
     __ ldr(r3, FieldMemOperand(r4, JSFunction::kSharedFunctionInfoOffset));
     __ ldr(r3, FieldMemOperand(r3, SharedFunctionInfo::kCodeOffset));
     __ add(r3, r3, Operand(Code::kHeaderSize - kHeapObjectTag));
     __ ldr(r2, FieldMemOperand(r1, JSGeneratorObject::kContinuationOffset));
     __ add(r3, r3, Operand(r2, ASR, 1));
     __ mov(r2, Operand(Smi::FromInt(JSGeneratorObject::kGeneratorExecuting)));
     __ str(r2, FieldMemOperand(r1, JSGeneratorObject::kContinuationOffset));
     __ Move(r0, r1);  // Continuation expects generator object in r0.
     __ Jump(r3);
   }
+
+  __ bind(&prepare_step_in_if_stepping);
+  {
+    FrameAndConstantPoolScope scope(masm, StackFrame::INTERNAL);
+    __ Push(r1, r2, r4);
+    __ CallRuntime(Runtime::kDebugPrepareStepInIfStepping);
+    __ Pop(r1, r2);
+    __ ldr(r4, FieldMemOperand(r1, JSGeneratorObject::kFunctionOffset));
+  }
+  __ b(&stepping_prepared);
+
+  __ bind(&prepare_step_in_suspended_generator);
+  {
+    FrameAndConstantPoolScope scope(masm, StackFrame::INTERNAL);
+    __ Push(r1, r2);
+    __ CallRuntime(Runtime::kDebugPrepareStepInSuspendedGenerator);
+    __ Pop(r1, r2);
+    __ ldr(r4, FieldMemOperand(r1, JSGeneratorObject::kFunctionOffset));
+  }
+  __ b(&stepping_prepared);
 }
 
 void Builtins::Generate_ConstructedNonConstructable(MacroAssembler* masm) {
   FrameScope scope(masm, StackFrame::INTERNAL);
   __ push(r1);
   __ CallRuntime(Runtime::kThrowConstructedNonConstructable);
 }
 
 
 enum IsTagged { kArgcIsSmiTagged, kArgcIsUntaggedInt };
@@ skipping 1932 matching lines @@
   }
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_ARM