[debugger] flood function for stepping before calling it.

src/mips/macro-assembler-mips.cc

Index: src/mips/macro-assembler-mips.cc
diff --git a/src/mips/macro-assembler-mips.cc b/src/mips/macro-assembler-mips.cc
index 1174808985bda35734b3ce0ff8bfd29d6fcc0ca3..72e668c58e9ae4499ac6c37bc608bfd6a0dbb540 100644
--- a/src/mips/macro-assembler-mips.cc
+++ b/src/mips/macro-assembler-mips.cc
@@ -4010,18 +4010,64 @@ 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());
+  li(t0, Operand(debug_step_action));
+  lb(t0, MemOperand(t0));
+  Branch(&skip_flooding, ne, t0, Operand(StepIn));
+  {
+    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(a1));
   DCHECK_IMPLIES(new_target.is_valid(), new_target.is(a3));
+
+  if (call_wrapper.NeedsDebugStepCheck()) {
+    FloodFunctionIfStepping(function, new_target, expected, actual);
+  }
+
+  // Clear the new.target register if not given.
   if (!new_target.is_valid()) {
     LoadRoot(a3, Heap::kUndefinedValueRootIndex);
   }
@@ -4031,6 +4077,11 @@ 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 = t0;
+    lw(code, FieldMemOperand(function, JSFunction::kCodeEntryOffset));
     if (flag == CALL_FUNCTION) {
       call_wrapper.BeforeCall(CallSize(code));
       Call(code);
@@ -4057,18 +4108,18 @@ void MacroAssembler::InvokeFunction(Register function,
   // Contract with called JS functions requires that function is passed in a1.
   DCHECK(function.is(a1));
   Register expected_reg = a2;
-  Register code_reg = t0;
+  Register temp_reg = t0;
 
-  lw(code_reg, FieldMemOperand(a1, JSFunction::kSharedFunctionInfoOffset));
+  lw(temp_reg, FieldMemOperand(a1, JSFunction::kSharedFunctionInfoOffset));
   lw(cp, FieldMemOperand(a1, JSFunction::kContextOffset));
   lw(expected_reg,
-      FieldMemOperand(code_reg,
-                      SharedFunctionInfo::kFormalParameterCountOffset));
+     FieldMemOperand(temp_reg,
+                     SharedFunctionInfo::kFormalParameterCountOffset));
   sra(expected_reg, expected_reg, kSmiTagSize);
-  lw(code_reg, FieldMemOperand(a1, JSFunction::kCodeEntryOffset));
 
   ParameterCount expected(expected_reg);
-  InvokeCode(code_reg, new_target, expected, actual, flag, call_wrapper);
+  InvokeFunctionCode(function, new_target, expected, actual, flag,
+                     call_wrapper);
 }
 
 
@@ -4086,11 +4137,7 @@ void MacroAssembler::InvokeFunction(Register function,
   // Get the function and setup the context.
   lw(cp, FieldMemOperand(a1, 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.
-  lw(t0, FieldMemOperand(a1, JSFunction::kCodeEntryOffset));
-  InvokeCode(t0, no_reg, expected, actual, flag, call_wrapper);
+  InvokeFunctionCode(a1, no_reg, expected, actual, flag, call_wrapper);
 }