// Copyright 2009 the V8 project authors. All rights reserved.
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// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
//       notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
//       copyright notice, this list of conditions and the following
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//
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#include "v8.h"

#include "codegen-inl.h"
#include "fast-codegen.h"

namespace v8 {
namespace internal {

#define __ ACCESS_MASM(masm_)

// Generate code for a JS function.  On entry to the function the receiver
// and arguments have been pushed on the stack left to right, with the
// return address on top of them.  The actual argument count matches the
// formal parameter count expected by the function.
//
// The live registers are:
//   o edi: the JS function object being called (ie, ourselves)
//   o esi: our context
//   o ebp: our caller's frame pointer
//   o esp: stack pointer (pointing to return address)
//
// The function builds a JS frame.  Please see JavaScriptFrameConstants in
// frames-ia32.h for its layout.
void FastCodeGenerator::Generate(FunctionLiteral* fun) {
  function_ = fun;
  SetFunctionPosition(fun);

  __ push(ebp);  // Caller's frame pointer.
  __ mov(ebp, esp);
  __ push(esi);  // Callee's context.
  __ push(edi);  // Callee's JS Function.

  { Comment cmnt(masm_, "[ Allocate locals");
    int locals_count = fun->scope()->num_stack_slots();
    for (int i = 0; i < locals_count; i++) {
      __ push(Immediate(Factory::undefined_value()));
    }
  }

  { Comment cmnt(masm_, "[ Stack check");
    Label ok;
    ExternalReference stack_guard_limit =
        ExternalReference::address_of_stack_guard_limit();
    __ cmp(esp, Operand::StaticVariable(stack_guard_limit));
    __ j(above_equal, &ok, taken);
    StackCheckStub stub;
    __ CallStub(&stub);
    __ bind(&ok);
  }

  { Comment cmnt(masm_, "[ Body");
    VisitStatements(fun->body());
  }

  { Comment cmnt(masm_, "[ return <undefined>;");
    // Emit a 'return undefined' in case control fell off the end of the
    // body.
    __ mov(eax, Factory::undefined_value());
    SetReturnPosition(fun);
    __ RecordJSReturn();
    // Do not use the leave instruction here because it is too short to
    // patch with the code required by the debugger.
    __ mov(esp, ebp);
    __ pop(ebp);
    __ ret((fun->scope()->num_parameters() + 1) * kPointerSize);
  }
}


void FastCodeGenerator::VisitExpressionStatement(ExpressionStatement* stmt) {
  Comment cmnt(masm_, "[ ExpressionStatement");
  SetStatementPosition(stmt);
  Visit(stmt->expression());
}


void FastCodeGenerator::VisitReturnStatement(ReturnStatement* stmt) {
  Comment cmnt(masm_, "[ ReturnStatement");
  SetStatementPosition(stmt);
  Visit(stmt->expression());
  __ pop(eax);
  __ RecordJSReturn();
  // Do not use the leave instruction here because it is too short to
  // patch with the code required by the debugger.
  __ mov(esp, ebp);
  __ pop(ebp);
  __ ret((function_->scope()->num_parameters() + 1) * kPointerSize);
}


void FastCodeGenerator::VisitVariableProxy(VariableProxy* expr) {
  Comment cmnt(masm_, "[ VariableProxy");
  Expression* rewrite = expr->var()->rewrite();
  ASSERT(rewrite != NULL);

  Slot* slot = rewrite->AsSlot();
  ASSERT(slot != NULL);
  { Comment cmnt(masm_, "[ Slot");
    if (expr->location().is_temporary()) {
      __ push(Operand(ebp, SlotOffset(slot)));
    } else {
      ASSERT(expr->location().is_nowhere());
    }
  }
}


void FastCodeGenerator::VisitLiteral(Literal* expr) {
  Comment cmnt(masm_, "[ Literal");
  if (expr->location().is_temporary()) {
    __ push(Immediate(expr->handle()));
  } else {
    ASSERT(expr->location().is_nowhere());
  }
}


void FastCodeGenerator::VisitAssignment(Assignment* expr) {
  Comment cmnt(masm_, "[ Assignment");
  ASSERT(expr->op() == Token::ASSIGN || expr->op() == Token::INIT_VAR);
  Visit(expr->value());

  Variable* var = expr->target()->AsVariableProxy()->AsVariable();
  ASSERT(var != NULL && var->slot() != NULL);

  if (expr->location().is_temporary()) {
    __ mov(eax, Operand(esp, 0));
    __ mov(Operand(ebp, SlotOffset(var->slot())), eax);
  } else {
    ASSERT(expr->location().is_nowhere());
    __ pop(Operand(ebp, SlotOffset(var->slot())));
  }
}


} }  // namespace v8::internal