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

src/mips/builtins-mips.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_MIPS
 
 #include "src/codegen.h"
 #include "src/debug/debug.h"
 #include "src/deoptimizer.h"
 #include "src/full-codegen/full-codegen.h"
@@ skipping 823 matching lines @@
                       kRAHasNotBeenSaved, kDontSaveFPRegs);
 
   // Store resume mode into generator object.
   __ sw(a2, FieldMemOperand(a1, JSGeneratorObject::kResumeModeOffset));
 
   // Load suspended function and context.
   __ lw(cp, FieldMemOperand(a1, JSGeneratorObject::kContextOffset));
   __ lw(t0, FieldMemOperand(a1, 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());
   __ li(t1, Operand(step_in_enabled));
   __ lb(t1, MemOperand(t1));
-  __ Branch(&skip_flooding, eq, t1, Operand(zero_reg));
-  {
-    FrameScope scope(masm, StackFrame::INTERNAL);
-    __ Push(a1, a2, t0);
-    __ CallRuntime(Runtime::kDebugPrepareStepInIfStepping);
-    __ Pop(a1, a2);
-    __ lw(t0, FieldMemOperand(a1, JSGeneratorObject::kFunctionOffset));
-  }
-  __ bind(&skip_flooding);
+  __ Branch(&prepare_step_in_if_stepping, ne, t1, Operand(zero_reg));
+
+  // Flood function if we need to continue stepping in the suspended generator.
+  ExternalReference debug_suspended_generator =
+      ExternalReference::debug_suspended_generator_address(masm->isolate());
+  __ li(t1, Operand(debug_suspended_generator));
+  __ lw(t1, MemOperand(t1));
+  __ Branch(&prepare_step_in_suspended_generator, eq, t1, Operand(zero_reg));
+  __ bind(&stepping_prepared);
 
   // Push receiver.
   __ lw(t1, FieldMemOperand(a1, JSGeneratorObject::kReceiverOffset));
   __ Push(t1);
 
   // ----------- S t a t e -------------
   //  -- a1    : the JSGeneratorObject to resume
   //  -- a2    : the resume mode (tagged)
   //  -- t0    : generator function
   //  -- cp    : generator context
@@ skipping 75 matching lines @@
     __ lw(a3, FieldMemOperand(a3, SharedFunctionInfo::kCodeOffset));
     __ Addu(a3, a3, Operand(Code::kHeaderSize - kHeapObjectTag));
     __ lw(a2, FieldMemOperand(a1, JSGeneratorObject::kContinuationOffset));
     __ SmiUntag(a2);
     __ Addu(a3, a3, Operand(a2));
     __ li(a2, Operand(Smi::FromInt(JSGeneratorObject::kGeneratorExecuting)));
     __ sw(a2, FieldMemOperand(a1, JSGeneratorObject::kContinuationOffset));
     __ Move(v0, a1);  // Continuation expects generator object in v0.
     __ Jump(a3);
   }
+
+  __ bind(&prepare_step_in_if_stepping);
+  {
+    FrameScope scope(masm, StackFrame::INTERNAL);
+    __ Push(a1, a2, t0);
+    __ CallRuntime(Runtime::kDebugPrepareStepInIfStepping);
+    __ Pop(a1, a2);
+  }
+  __ Branch(USE_DELAY_SLOT, &stepping_prepared);
+  __ lw(t0, FieldMemOperand(a1, JSGeneratorObject::kFunctionOffset));
+
+  __ bind(&prepare_step_in_suspended_generator);
+  {
+    FrameScope scope(masm, StackFrame::INTERNAL);
+    __ Push(a1, a2);
+    __ CallRuntime(Runtime::kDebugPrepareStepInSuspendedGenerator);
+    __ Pop(a1, a2);
+  }
+  __ Branch(USE_DELAY_SLOT, &stepping_prepared);
+  __ lw(t0, FieldMemOperand(a1, JSGeneratorObject::kFunctionOffset));
 }
 
 static void LeaveInterpreterFrame(MacroAssembler* masm, Register scratch) {
   Register args_count = scratch;
 
   // Get the arguments + receiver count.
   __ lw(args_count,
         MemOperand(fp, InterpreterFrameConstants::kBytecodeArrayFromFp));
   __ lw(args_count,
         FieldMemOperand(args_count, BytecodeArray::kParameterSizeOffset));
@@ skipping 1897 matching lines @@
   }
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_MIPS