[debugger] flood function for stepping before calling it.

src/ia32/macro-assembler-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/base/bits.h"
 #include "src/base/division-by-constant.h"
 #include "src/bootstrapper.h"
 #include "src/codegen.h"
@@ skipping 1968 matching lines @@
         jmp(done, done_near);
       }
     } else {
       jmp(adaptor, RelocInfo::CODE_TARGET);
     }
     bind(&invoke);
   }
 }
 
 
-void MacroAssembler::InvokeCode(const Operand& 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());
+  cmpb(Operand::StaticVariable(debug_step_action), StepIn);
+  j(not_equal, &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());
+  DCHECK(function.is(edi));
+  DCHECK_IMPLIES(new_target.is_valid(), new_target.is(edx));
 
-  // Ensure new target is passed in the correct register. Otherwise clear the
-  // appropriate register in case new target is not given.
-  DCHECK_IMPLIES(new_target.is_valid(), new_target.is(edx));
+  if (call_wrapper.NeedsDebugStepCheck()) {
+    FloodFunctionIfStepping(function, new_target, expected, actual);
+  }
+
+  // Clear the new.target register if not given.
   if (!new_target.is_valid()) {
     mov(edx, isolate()->factory()->undefined_value());
   }
 
   Label done;
   bool definitely_mismatches = false;
   InvokePrologue(expected, actual, &done, &definitely_mismatches, flag,
                  Label::kNear, 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.
+    Operand code = FieldOperand(function, JSFunction::kCodeEntryOffset);
     if (flag == CALL_FUNCTION) {
       call_wrapper.BeforeCall(CallSize(code));
       call(code);
       call_wrapper.AfterCall();
     } else {
       DCHECK(flag == JUMP_FUNCTION);
       jmp(code);
     }
     bind(&done);
   }
 }
 
 
 void MacroAssembler::InvokeFunction(Register fun,
                                     Register new_target,
                                     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());
 
   DCHECK(fun.is(edi));
   mov(ebx, FieldOperand(edi, JSFunction::kSharedFunctionInfoOffset));
   mov(esi, FieldOperand(edi, JSFunction::kContextOffset));
   mov(ebx, FieldOperand(ebx, SharedFunctionInfo::kFormalParameterCountOffset));
   SmiUntag(ebx);
 
   ParameterCount expected(ebx);
-  InvokeCode(FieldOperand(edi, JSFunction::kCodeEntryOffset), new_target,
-             expected, actual, flag, call_wrapper);
+  InvokeFunctionCode(edi, new_target, expected, actual, flag, call_wrapper);
 }
 
 
 void MacroAssembler::InvokeFunction(Register fun,
                                     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());
 
   DCHECK(fun.is(edi));
   mov(esi, FieldOperand(edi, JSFunction::kContextOffset));
 
-  InvokeCode(FieldOperand(edi, JSFunction::kCodeEntryOffset), no_reg,
-             expected, actual, flag, call_wrapper);
+  InvokeFunctionCode(edi, no_reg, expected, actual, flag, call_wrapper);
 }
 
 
 void MacroAssembler::InvokeFunction(Handle<JSFunction> function,
                                     const ParameterCount& expected,
                                     const ParameterCount& actual,
                                     InvokeFlag flag,
                                     const CallWrapper& call_wrapper) {
   LoadHeapObject(edi, function);
   InvokeFunction(edi, expected, actual, flag, call_wrapper);
 }
 
 
 void MacroAssembler::InvokeBuiltin(int native_context_index, InvokeFlag flag,
                                    const CallWrapper& call_wrapper) {
   // You can't call a builtin without a valid frame.
   DCHECK(flag == JUMP_FUNCTION || has_frame());
 
   // Rely on the assertion to check that the number of provided
   // arguments match the expected number of arguments. Fake a
   // parameter count to avoid emitting code to do the check.
   ParameterCount expected(0);
   GetBuiltinFunction(edi, native_context_index);
-  InvokeCode(FieldOperand(edi, JSFunction::kCodeEntryOffset), no_reg,
-             expected, expected, flag, call_wrapper);
+  InvokeFunctionCode(edi, no_reg, expected, expected, flag, call_wrapper);
 }
 
 
 void MacroAssembler::GetBuiltinFunction(Register target,
                                         int native_context_index) {
   // Load the JavaScript builtin function from the builtins object.
   mov(target, GlobalObjectOperand());
   mov(target, FieldOperand(target, JSGlobalObject::kNativeContextOffset));
   mov(target, ContextOperand(target, native_context_index));
 }
 
 
-void MacroAssembler::GetBuiltinEntry(Register target,
-                                     int native_context_index) {
-  DCHECK(!target.is(edi));
-  // Load the JavaScript builtin function from the builtins object.
-  GetBuiltinFunction(edi, native_context_index);
-  // Load the code entry point from the function into the target register.
-  mov(target, FieldOperand(edi, JSFunction::kCodeEntryOffset));
-}
-
-
 void MacroAssembler::LoadContext(Register dst, int context_chain_length) {
   if (context_chain_length > 0) {
     // Move up the chain of contexts to the context containing the slot.
     mov(dst, Operand(esi, Context::SlotOffset(Context::PREVIOUS_INDEX)));
     for (int i = 1; i < context_chain_length; i++) {
       mov(dst, Operand(dst, Context::SlotOffset(Context::PREVIOUS_INDEX)));
     }
   } else {
     // Slot is in the current function context.  Move it into the
     // destination register in case we store into it (the write barrier
@@ skipping 1033 matching lines @@
   mov(eax, dividend);
   shr(eax, 31);
   add(edx, eax);
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_IA32