v8/src/ia32/fast-codegen-ia32.cc

// 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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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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#include "v8.h"

#include "codegen-inl.h"
#include "fast-codegen.h"
#include "parser.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_, "[ Declarations");
    VisitDeclarations(fun->scope()->declarations());
  }

  { 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::DeclareGlobals(Handle<FixedArray> pairs) {
  // Call the runtime to declare the globals.
  __ push(esi);  // The context is the first argument.
  __ push(Immediate(pairs));
  __ push(Immediate(Smi::FromInt(is_eval_ ? 1 : 0)));
  __ CallRuntime(Runtime::kDeclareGlobals, 3);
  // Return value is ignored.
}


void FastCodeGenerator::VisitBlock(Block* stmt) {
  Comment cmnt(masm_, "[ Block");
  SetStatementPosition(stmt);
  VisitStatements(stmt->statements());
}


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);
  Expression* expr = stmt->expression();
  Visit(expr);

  // Complete the statement based on the location of the subexpression.
  Location source = expr->location();
  ASSERT(!source.is_nowhere());
  if (source.is_temporary()) {
    __ pop(eax);
  } else {
    ASSERT(source.is_constant());
    ASSERT(expr->AsLiteral() != NULL);
    __ mov(eax, expr->AsLiteral()->handle());
  }
  __ 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::VisitFunctionLiteral(FunctionLiteral* expr) {
  Comment cmnt(masm_, "[ FunctionLiteral");

  // Build the function boilerplate and instantiate it.
  Handle<JSFunction> boilerplate = BuildBoilerplate(expr);
  if (HasStackOverflow()) return;

  ASSERT(boilerplate->IsBoilerplate());

  // Create a new closure.
  __ push(esi);
  __ push(Immediate(boilerplate));
  __ CallRuntime(Runtime::kNewClosure, 2);

  if (expr->location().is_temporary()) {
    __ push(eax);
  } else {
    ASSERT(expr->location().is_nowhere());
  }
}


void FastCodeGenerator::VisitVariableProxy(VariableProxy* expr) {
  Comment cmnt(masm_, "[ VariableProxy");
  Expression* rewrite = expr->var()->rewrite();
  if (rewrite == NULL) {
    Comment cmnt(masm_, "Global variable");
    // Use inline caching. Variable name is passed in ecx and the global
    // object on the stack.
    __ push(CodeGenerator::GlobalObject());
    __ mov(ecx, expr->name());
    Handle<Code> ic(Builtins::builtin(Builtins::LoadIC_Initialize));
    __ call(ic, RelocInfo::CODE_TARGET_CONTEXT);

    // A test eax instruction following the call is used by the IC to
    // indicate that the inobject property case was inlined.  Ensure there
    // is no test eax instruction here.  Remember that the assembler may
    // choose to do peephole optimization (eg, push/pop elimination).
    if (expr->location().is_temporary()) {
      // Replace the global object with the result.
      __ mov(Operand(esp, 0), eax);
    } else {
      ASSERT(expr->location().is_nowhere());
      __ add(Operand(esp), Immediate(kPointerSize));
    }

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


void FastCodeGenerator::VisitRegExpLiteral(RegExpLiteral* expr) {
  Comment cmnt(masm_, "[ RegExp Literal");
  Label done;
  // Registers will be used as follows:
  // edi = JS function.
  // ebx = literals array.
  // eax = regexp literal.
  __ mov(edi, Operand(ebp, JavaScriptFrameConstants::kFunctionOffset));
  __ mov(ebx, FieldOperand(edi, JSFunction::kLiteralsOffset));
  int literal_offset =
    FixedArray::kHeaderSize + expr->literal_index() * kPointerSize;
  __ mov(eax, FieldOperand(ebx, literal_offset));
  __ cmp(eax, Factory::undefined_value());
  __ j(not_equal, &done);
  // Create regexp literal using runtime function
  // Result will be in eax.
  __ push(ebx);
  __ push(Immediate(Smi::FromInt(expr->literal_index())));
  __ push(Immediate(expr->pattern()));
  __ push(Immediate(expr->flags()));
  __ CallRuntime(Runtime::kMaterializeRegExpLiteral, 4);
  // Label done:
  __ bind(&done);
  if (expr->location().is_temporary()) {
    __ push(eax);
  } else {
    ASSERT(expr->location().is_nowhere());
  }
}


void FastCodeGenerator::VisitArrayLiteral(ArrayLiteral* expr) {
  Comment cmnt(masm_, "[ ArrayLiteral");
  Label make_clone;

  // Fetch the function's literals array.
  __ mov(ebx, Operand(ebp, JavaScriptFrameConstants::kFunctionOffset));
  __ mov(ebx, FieldOperand(ebx, JSFunction::kLiteralsOffset));
  // Check if the literal's boilerplate has been instantiated.
  int offset =
      FixedArray::kHeaderSize + (expr->literal_index() * kPointerSize);
  __ mov(eax, FieldOperand(ebx, offset));
  __ cmp(eax, Factory::undefined_value());
  __ j(not_equal, &make_clone);

  // Instantiate the boilerplate.
  __ push(ebx);
  __ push(Immediate(Smi::FromInt(expr->literal_index())));
  __ push(Immediate(expr->literals()));
  __ CallRuntime(Runtime::kCreateArrayLiteralBoilerplate, 3);

  __ bind(&make_clone);
  // Clone the boilerplate.
  __ push(eax);
  if (expr->depth() > 1) {
    __ CallRuntime(Runtime::kCloneLiteralBoilerplate, 1);
  } else {
    __ CallRuntime(Runtime::kCloneShallowLiteralBoilerplate, 1);
  }

  bool result_saved = false;  // Is the result saved to the stack?

  // Emit code to evaluate all the non-constant subexpressions and to store
  // them into the newly cloned array.
  ZoneList<Expression*>* subexprs = expr->values();
  for (int i = 0, len = subexprs->length(); i < len; i++) {
    Expression* subexpr = subexprs->at(i);
    // If the subexpression is a literal or a simple materialized literal it
    // is already set in the cloned array.
    if (subexpr->AsLiteral() != NULL ||
        CompileTimeValue::IsCompileTimeValue(subexpr)) {
      continue;
    }

    if (!result_saved) {
      __ push(eax);
      result_saved = true;
    }
    Visit(subexpr);
    ASSERT(subexpr->location().is_temporary());

    // Store the subexpression value in the array's elements.
    __ pop(eax);  // Subexpression value.
    __ mov(ebx, Operand(esp, 0));  // Copy of array literal.
    __ mov(ebx, FieldOperand(ebx, JSObject::kElementsOffset));
    int offset = FixedArray::kHeaderSize + (i * kPointerSize);
    __ mov(FieldOperand(ebx, offset), eax);

    // Update the write barrier for the array store.
    __ RecordWrite(ebx, offset, eax, ecx);
  }

  Location destination = expr->location();
  if (destination.is_nowhere() && result_saved) {
    __ add(Operand(esp), Immediate(kPointerSize));
  } else if (destination.is_temporary() && !result_saved) {
    __ push(eax);
  }
}


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

  // Left-hand side can only be a global or a (parameter or local) slot.
  Variable* var = expr->target()->AsVariableProxy()->AsVariable();
  ASSERT(var != NULL);
  ASSERT(var->is_global() || var->slot() != NULL);

  // Complete the assignment based on the location of the right-hand-side
  // value and the desired location of the assignment value.
  Location destination = expr->location();
  Location source = rhs->location();
  ASSERT(!destination.is_constant());
  ASSERT(!source.is_nowhere());

  if (var->is_global()) {
    // Assignment to a global variable, use inline caching.  Right-hand-side
    // value is passed in eax, variable name in ecx, and the global object
    // on the stack.
    if (source.is_temporary()) {
      __ pop(eax);
    } else {
      ASSERT(source.is_constant());
      ASSERT(rhs->AsLiteral() != NULL);
      __ mov(eax, rhs->AsLiteral()->handle());
    }
    __ mov(ecx, var->name());
    __ push(CodeGenerator::GlobalObject());
    Handle<Code> ic(Builtins::builtin(Builtins::StoreIC_Initialize));
    __ call(ic, RelocInfo::CODE_TARGET);
    // Overwrite the global object on the stack with the result if needed.
    if (destination.is_temporary()) {
      __ mov(Operand(esp, 0), eax);
    } else {
      ASSERT(destination.is_nowhere());
      __ add(Operand(esp), Immediate(kPointerSize));
    }

  } else {
    // Local or parameter assignment.
    if (source.is_temporary()) {
      if (destination.is_temporary()) {
        // Case 'temp1 <- (var = temp0)'.  Preserve right-hand-side
        // temporary on the stack.
        __ mov(eax, Operand(esp, 0));
        __ mov(Operand(ebp, SlotOffset(var->slot())), eax);
      } else {
        ASSERT(destination.is_nowhere());
        // Case 'var = temp'.  Discard right-hand-side temporary.
        __ pop(Operand(ebp, SlotOffset(var->slot())));
      }
    } else {
      ASSERT(source.is_constant());
      ASSERT(rhs->AsLiteral() != NULL);
      // Two cases: 'temp <- (var = constant)', or 'var = constant' with a
      // discarded result.  Always perform the assignment.
      __ mov(eax, rhs->AsLiteral()->handle());
      __ mov(Operand(ebp, SlotOffset(var->slot())), eax);
      if (destination.is_temporary()) {
        // Case 'temp <- (var = constant)'.  Save result.
        __ push(eax);
      }
    }
  }
}


void FastCodeGenerator::VisitCall(Call* expr) {
  Expression* fun = expr->expression();
  ZoneList<Expression*>* args = expr->arguments();
  Variable* var = fun->AsVariableProxy()->AsVariable();
  ASSERT(var != NULL && !var->is_this() && var->is_global());
  ASSERT(!var->is_possibly_eval());

  __ push(Immediate(var->name()));
  // Push global object (receiver).
  __ push(CodeGenerator::GlobalObject());
  int arg_count = args->length();
  for (int i = 0; i < arg_count; i++) {
    Visit(args->at(i));
    ASSERT(!args->at(i)->location().is_nowhere());
    if (args->at(i)->location().is_constant()) {
      ASSERT(args->at(i)->AsLiteral() != NULL);
      __ push(Immediate(args->at(i)->AsLiteral()->handle()));
    }
  }
  // Record source position for debugger
  SetSourcePosition(expr->position());
  // Call the IC initialization code.
  Handle<Code> ic = CodeGenerator::ComputeCallInitialize(arg_count,
                                                         NOT_IN_LOOP);
  __ call(ic, RelocInfo::CODE_TARGET_CONTEXT);
  // Restore context register.
  __ mov(esi, Operand(ebp, StandardFrameConstants::kContextOffset));
  // Discard the function left on TOS.
  if (expr->location().is_temporary()) {
    __ mov(Operand(esp, 0), eax);
  } else {
    ASSERT(expr->location().is_nowhere());
    __ add(Operand(esp), Immediate(kPointerSize));
  }
}


void FastCodeGenerator::VisitCallRuntime(CallRuntime* expr) {
  Comment cmnt(masm_, "[ CallRuntime");
  ZoneList<Expression*>* args = expr->arguments();
  Runtime::Function* function = expr->function();

  ASSERT(function != NULL);

  // Push the arguments ("left-to-right").
  int arg_count = args->length();
  for (int i = 0; i < arg_count; i++) {
    Visit(args->at(i));
    ASSERT(!args->at(i)->location().is_nowhere());
    if (args->at(i)->location().is_constant()) {
      ASSERT(args->at(i)->AsLiteral() != NULL);
      __ push(Immediate(args->at(i)->AsLiteral()->handle()));
    } else {
      ASSERT(args->at(i)->location().is_temporary());
      // If location is temporary, it is already on the stack,
      // so nothing to do here.
    }
  }

  __ CallRuntime(function, arg_count);
  if (expr->location().is_temporary()) {
    __ push(eax);
  } else {
    ASSERT(expr->location().is_nowhere());
  }
}


} }  // namespace v8::internal