[debugger] flood function for stepping before calling it.

src/arm/macro-assembler-arm.cc

Index: src/arm/macro-assembler-arm.cc
diff --git a/src/arm/macro-assembler-arm.cc b/src/arm/macro-assembler-arm.cc
index 2565328abef594157cc4ee6d5a8420cca5775676..8ad56a81835dff3042e504fc6d67f8dae252b5b0 100644
--- a/src/arm/macro-assembler-arm.cc
+++ b/src/arm/macro-assembler-arm.cc
@@ -1303,18 +1303,65 @@ void MacroAssembler::InvokePrologue(const ParameterCount& expected,
 }
 
 
-void MacroAssembler::InvokeCode(Register code,
-                                Register new_target,
-                                const ParameterCount& expected,
-                                const ParameterCount& actual,
-                                InvokeFlag flag,
-                                const CallWrapper& call_wrapper) {
+void MacroAssembler::FloodFunctionIfStepping(Register fun, Register new_target,
+                                             const ParameterCount& expected,
+                                             const ParameterCount& actual) {
+  Label skip_flooding;
+  ExternalReference debug_step_action =
+      ExternalReference::debug_last_step_action_address(isolate());
+  mov(r4, Operand(debug_step_action));
+  ldrb(r4, MemOperand(r4));
+  cmp(r4, Operand(StepIn));
+  b(ne, &skip_flooding);
+  {
+    FrameScope frame(this,
+                     has_frame() ? StackFrame::NONE : StackFrame::INTERNAL);
+    if (expected.is_reg()) {
+      SmiTag(expected.reg());
+      Push(expected.reg());
+    }
+    if (actual.is_reg()) {
+      SmiTag(actual.reg());
+      Push(actual.reg());
+    }
+    if (new_target.is_valid()) {
+      Push(new_target);
+    }
+    Push(fun);
+    Push(fun);
+    CallRuntime(Runtime::kDebugPrepareStepInIfStepping, 1);
+    Pop(fun);
+    if (new_target.is_valid()) {
+      Pop(new_target);
+    }
+    if (actual.is_reg()) {
+      Pop(actual.reg());
+      SmiUntag(actual.reg());
+    }
+    if (expected.is_reg()) {
+      Pop(expected.reg());
+      SmiUntag(expected.reg());
+    }
+  }
+  bind(&skip_flooding);
+}
+
+
+void MacroAssembler::InvokeFunctionCode(Register function, Register new_target,
+                                        const ParameterCount& expected,
+                                        const ParameterCount& actual,
+                                        InvokeFlag flag,
+                                        const CallWrapper& call_wrapper) {
   // You can't call a function without a valid frame.
   DCHECK(flag == JUMP_FUNCTION || has_frame());
-
-  // Ensure new target is passed in the correct register. Otherwise clear the
-  // appropriate register in case new target is not given.
+  DCHECK(function.is(r1));
   DCHECK_IMPLIES(new_target.is_valid(), new_target.is(r3));
+
+  if (call_wrapper.NeedsDebugStepCheck()) {
+    FloodFunctionIfStepping(function, new_target, expected, actual);
+  }
+
+  // Clear the new.target register if not given.
   if (!new_target.is_valid()) {
     LoadRoot(r3, Heap::kUndefinedValueRootIndex);
   }
@@ -1324,6 +1371,11 @@ void MacroAssembler::InvokeCode(Register code,
   InvokePrologue(expected, actual, &done, &definitely_mismatches, flag,
                  call_wrapper);
   if (!definitely_mismatches) {
+    // We call indirectly through the code field in the function to
+    // allow recompilation to take effect without changing any of the
+    // call sites.
+    Register code = r4;
+    ldr(code, FieldMemOperand(function, JSFunction::kCodeEntryOffset));
     if (flag == CALL_FUNCTION) {
       call_wrapper.BeforeCall(CallSize(code));
       Call(code);
@@ -1352,19 +1404,17 @@ void MacroAssembler::InvokeFunction(Register fun,
   DCHECK(fun.is(r1));
 
   Register expected_reg = r2;
-  Register code_reg = r4;
+  Register temp_reg = r4;
 
-  ldr(code_reg, FieldMemOperand(r1, JSFunction::kSharedFunctionInfoOffset));
+  ldr(temp_reg, FieldMemOperand(r1, JSFunction::kSharedFunctionInfoOffset));
   ldr(cp, FieldMemOperand(r1, JSFunction::kContextOffset));
   ldr(expected_reg,
-      FieldMemOperand(code_reg,
+      FieldMemOperand(temp_reg,
                       SharedFunctionInfo::kFormalParameterCountOffset));
   SmiUntag(expected_reg);
-  ldr(code_reg,
-      FieldMemOperand(r1, JSFunction::kCodeEntryOffset));
 
   ParameterCount expected(expected_reg);
-  InvokeCode(code_reg, new_target, expected, actual, flag, call_wrapper);
+  InvokeFunctionCode(fun, new_target, expected, actual, flag, call_wrapper);
 }
 
 
@@ -1382,11 +1432,7 @@ void MacroAssembler::InvokeFunction(Register function,
   // Get the function and setup the context.
   ldr(cp, FieldMemOperand(r1, JSFunction::kContextOffset));
 
-  // We call indirectly through the code field in the function to
-  // allow recompilation to take effect without changing any of the
-  // call sites.
-  ldr(r4, FieldMemOperand(r1, JSFunction::kCodeEntryOffset));
-  InvokeCode(r4, no_reg, expected, actual, flag, call_wrapper);
+  InvokeFunctionCode(r1, no_reg, expected, actual, flag, call_wrapper);
 }