src/mips/codegen-mips.h

// Copyright 2010 the V8 project authors. All rights reserved.
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#ifndef V8_MIPS_CODEGEN_MIPS_H_
#define V8_MIPS_CODEGEN_MIPS_H_

namespace v8 {
namespace internal {

// Forward declarations
class CompilationInfo;
class DeferredCode;
class RegisterAllocator;
class RegisterFile;

enum InitState { CONST_INIT, NOT_CONST_INIT };
enum TypeofState { INSIDE_TYPEOF, NOT_INSIDE_TYPEOF };


// -----------------------------------------------------------------------------
// Reference support

// A reference is a C++ stack-allocated object that keeps an ECMA
// reference on the execution stack while in scope. For variables
// the reference is empty, indicating that it isn't necessary to
// store state on the stack for keeping track of references to those.
// For properties, we keep either one (named) or two (indexed) values
// on the execution stack to represent the reference.
class Reference BASE_EMBEDDED {
 public:
  // The values of the types is important, see size().
  enum Type { UNLOADED = -2, ILLEGAL = -1, SLOT = 0, NAMED = 1, KEYED = 2 };
  Reference(CodeGenerator* cgen,
            Expression* expression,
            bool persist_after_get = false);
  ~Reference();

  Expression* expression() const { return expression_; }
  Type type() const { return type_; }
  void set_type(Type value) {
    ASSERT_EQ(ILLEGAL, type_);
    type_ = value;
  }

  void set_unloaded() {
    ASSERT_NE(ILLEGAL, type_);
    ASSERT_NE(UNLOADED, type_);
    type_ = UNLOADED;
  }
  // The size the reference takes up on the stack.
  int size() const {
    return (type_ < SLOT) ? 0 : type_;
  }

  bool is_illegal() const { return type_ == ILLEGAL; }
  bool is_slot() const { return type_ == SLOT; }
  bool is_property() const { return type_ == NAMED || type_ == KEYED; }
  bool is_unloaded() const { return type_ == UNLOADED; }

  // Return the name. Only valid for named property references.
  Handle<String> GetName();

  // Generate code to push the value of the reference on top of the
  // expression stack.  The reference is expected to be already on top of
  // the expression stack, and it is consumed by the call unless the
  // reference is for a compound assignment.
  // If the reference is not consumed, it is left in place under its value.
  void GetValue();

  // Generate code to pop a reference, push the value of the reference,
  // and then spill the stack frame.
  inline void GetValueAndSpill();

  // Generate code to store the value on top of the expression stack in the
  // reference.  The reference is expected to be immediately below the value
  // on the expression stack.  The  value is stored in the location specified
  // by the reference, and is left on top of the stack, after the reference
  // is popped from beneath it (unloaded).
  void SetValue(InitState init_state);

 private:
  CodeGenerator* cgen_;
  Expression* expression_;
  Type type_;
  // Keep the reference on the stack after get, so it can be used by set later.
  bool persist_after_get_;
};


// -----------------------------------------------------------------------------
// Code generation state

// The state is passed down the AST by the code generator (and back up, in
// the form of the state of the label pair).  It is threaded through the
// call stack.  Constructing a state implicitly pushes it on the owning code
// generator's stack of states, and destroying one implicitly pops it.

class CodeGenState BASE_EMBEDDED {
 public:
  // Create an initial code generator state.  Destroying the initial state
  // leaves the code generator with a NULL state.
  explicit CodeGenState(CodeGenerator* owner);

  // Create a code generator state based on a code generator's current
  // state.  The new state has its own typeof state and pair of branch
  // labels.
  CodeGenState(CodeGenerator* owner,
               JumpTarget* true_target,
               JumpTarget* false_target);

  // Destroy a code generator state and restore the owning code generator's
  // previous state.
  ~CodeGenState();

  TypeofState typeof_state() const { return typeof_state_; }
  JumpTarget* true_target() const { return true_target_; }
  JumpTarget* false_target() const { return false_target_; }

 private:
  // The owning code generator.
  CodeGenerator* owner_;

  // A flag indicating whether we are compiling the immediate subexpression
  // of a typeof expression.
  TypeofState typeof_state_;

  JumpTarget* true_target_;
  JumpTarget* false_target_;

  // The previous state of the owning code generator, restored when
  // this state is destroyed.
  CodeGenState* previous_;
};


// -----------------------------------------------------------------------------
// CodeGenerator

class CodeGenerator: public AstVisitor {
 public:
  // Compilation mode.  Either the compiler is used as the primary
  // compiler and needs to setup everything or the compiler is used as
  // the secondary compiler for split compilation and has to handle
  // bailouts.
  enum Mode {
    PRIMARY,
    SECONDARY
  };

  // Takes a function literal, generates code for it. This function should only
  // be called by compiler.cc.
  static Handle<Code> MakeCode(CompilationInfo* info);

  // Printing of AST, etc. as requested by flags.
  static void MakeCodePrologue(CompilationInfo* info);

  // Allocate and install the code.
  static Handle<Code> MakeCodeEpilogue(MacroAssembler* masm,
                                       Code::Flags flags,
                                       CompilationInfo* info);

#ifdef ENABLE_LOGGING_AND_PROFILING
  static bool ShouldGenerateLog(Expression* type);
#endif

  static void SetFunctionInfo(Handle<JSFunction> fun,
                              FunctionLiteral* lit,
                              bool is_toplevel,
                              Handle<Script> script);

  static void RecordPositions(MacroAssembler* masm, int pos);

  // Accessors
  MacroAssembler* masm() { return masm_; }
  VirtualFrame* frame() const { return frame_; }
  inline Handle<Script> script();

  bool has_valid_frame() const { return frame_ != NULL; }

  // Set the virtual frame to be new_frame, with non-frame register
  // reference counts given by non_frame_registers.  The non-frame
  // register reference counts of the old frame are returned in
  // non_frame_registers.
  void SetFrame(VirtualFrame* new_frame, RegisterFile* non_frame_registers);

  void DeleteFrame();

  RegisterAllocator* allocator() const { return allocator_; }

  CodeGenState* state() { return state_; }
  void set_state(CodeGenState* state) { state_ = state; }

  void AddDeferred(DeferredCode* code) { deferred_.Add(code); }

  static const int kUnknownIntValue = -1;

  // Number of instructions used for the JS return sequence. The constant is
  // used by the debugger to patch the JS return sequence.
  static const int kJSReturnSequenceLength = 7;

  // If the name is an inline runtime function call return the number of
  // expected arguments. Otherwise return -1.
  static int InlineRuntimeCallArgumentsCount(Handle<String> name);

 private:
  // Construction/Destruction.
  explicit CodeGenerator(MacroAssembler* masm);

  // Accessors.
  inline bool is_eval();
  inline Scope* scope();

  // Generating deferred code.
  void ProcessDeferred();

  // State
  bool has_cc() const  { return cc_reg_ != cc_always; }
  TypeofState typeof_state() const { return state_->typeof_state(); }
  JumpTarget* true_target() const  { return state_->true_target(); }
  JumpTarget* false_target() const  { return state_->false_target(); }

  // We don't track loop nesting level on mips yet.
  int loop_nesting() const { return 0; }

  // Node visitors.
  void VisitStatements(ZoneList<Statement*>* statements);

#define DEF_VISIT(type) \
  void Visit##type(type* node);
  AST_NODE_LIST(DEF_VISIT)
#undef DEF_VISIT

  // Visit a statement and then spill the virtual frame if control flow can
  // reach the end of the statement (ie, it does not exit via break,
  // continue, return, or throw).  This function is used temporarily while
  // the code generator is being transformed.
  inline void VisitAndSpill(Statement* statement);

  // Visit a list of statements and then spill the virtual frame if control
  // flow can reach the end of the list.
  inline void VisitStatementsAndSpill(ZoneList<Statement*>* statements);

  // Main code generation function
  void Generate(CompilationInfo* info);

  // The following are used by class Reference.
  void LoadReference(Reference* ref);
  void UnloadReference(Reference* ref);

  MemOperand ContextOperand(Register context, int index) const {
    return MemOperand(context, Context::SlotOffset(index));
  }

  MemOperand SlotOperand(Slot* slot, Register tmp);

  // Expressions
  MemOperand GlobalObject() const  {
    return ContextOperand(cp, Context::GLOBAL_INDEX);
  }

  void LoadCondition(Expression* x,
                     JumpTarget* true_target,
                     JumpTarget* false_target,
                     bool force_cc);
  void Load(Expression* x);
  void LoadGlobal();

  // Generate code to push the value of an expression on top of the frame
  // and then spill the frame fully to memory.  This function is used
  // temporarily while the code generator is being transformed.
  inline void LoadAndSpill(Expression* expression);

  // Read a value from a slot and leave it on top of the expression stack.
  void LoadFromSlot(Slot* slot, TypeofState typeof_state);
  // Store the value on top of the stack to a slot.
  void StoreToSlot(Slot* slot, InitState init_state);

  struct InlineRuntimeLUT {
    void (CodeGenerator::*method)(ZoneList<Expression*>*);
    const char* name;
    int nargs;
  };

  static InlineRuntimeLUT* FindInlineRuntimeLUT(Handle<String> name);
  bool CheckForInlineRuntimeCall(CallRuntime* node);
  static bool PatchInlineRuntimeEntry(Handle<String> name,
                                      const InlineRuntimeLUT& new_entry,
                                      InlineRuntimeLUT* old_entry);

  static Handle<Code> ComputeLazyCompile(int argc);
  void ProcessDeclarations(ZoneList<Declaration*>* declarations);

  Handle<Code> ComputeCallInitialize(int argc, InLoopFlag in_loop);

  // Declare global variables and functions in the given array of
  // name/value pairs.
  void DeclareGlobals(Handle<FixedArray> pairs);

  // Support for type checks.
  void GenerateIsSmi(ZoneList<Expression*>* args);
  void GenerateIsNonNegativeSmi(ZoneList<Expression*>* args);
  void GenerateIsArray(ZoneList<Expression*>* args);
  void GenerateIsRegExp(ZoneList<Expression*>* args);

  // Support for construct call checks.
  void GenerateIsConstructCall(ZoneList<Expression*>* args);

  // Support for arguments.length and arguments[?].
  void GenerateArgumentsLength(ZoneList<Expression*>* args);
  void GenerateArguments(ZoneList<Expression*>* args);

  // Support for accessing the class and value fields of an object.
  void GenerateClassOf(ZoneList<Expression*>* args);
  void GenerateValueOf(ZoneList<Expression*>* args);
  void GenerateSetValueOf(ZoneList<Expression*>* args);

  // Fast support for charCodeAt(n).
  void GenerateFastCharCodeAt(ZoneList<Expression*>* args);

  // Fast support for string.charAt(n) and string[n].
  void GenerateCharFromCode(ZoneList<Expression*>* args);

  // Fast support for object equality testing.
  void GenerateObjectEquals(ZoneList<Expression*>* args);

  void GenerateLog(ZoneList<Expression*>* args);

  // Fast support for Math.random().
  void GenerateRandomHeapNumber(ZoneList<Expression*>* args);

  void GenerateIsObject(ZoneList<Expression*>* args);
  void GenerateIsFunction(ZoneList<Expression*>* args);
  void GenerateIsUndetectableObject(ZoneList<Expression*>* args);
  void GenerateStringAdd(ZoneList<Expression*>* args);
  void GenerateSubString(ZoneList<Expression*>* args);
  void GenerateStringCompare(ZoneList<Expression*>* args);
  void GenerateRegExpExec(ZoneList<Expression*>* args);
  void GenerateNumberToString(ZoneList<Expression*>* args);

  // Fast call to math functions.
  void GenerateMathPow(ZoneList<Expression*>* args);
  void GenerateMathSin(ZoneList<Expression*>* args);
  void GenerateMathCos(ZoneList<Expression*>* args);
  void GenerateMathSqrt(ZoneList<Expression*>* args);

  // Simple condition analysis.
  enum ConditionAnalysis {
    ALWAYS_TRUE,
    ALWAYS_FALSE,
    DONT_KNOW
  };
  ConditionAnalysis AnalyzeCondition(Expression* cond);

  // Methods used to indicate which source code is generated for. Source
  // positions are collected by the assembler and emitted with the relocation
  // information.
  void CodeForFunctionPosition(FunctionLiteral* fun);
  void CodeForReturnPosition(FunctionLiteral* fun);
  void CodeForStatementPosition(Statement* node);
  void CodeForDoWhileConditionPosition(DoWhileStatement* stmt);
  void CodeForSourcePosition(int pos);

#ifdef DEBUG
  // True if the registers are valid for entry to a block.
  bool HasValidEntryRegisters();
#endif

  bool is_eval_;  // Tells whether code is generated for eval.

  Handle<Script> script_;
  List<DeferredCode*> deferred_;

  // Assembler
  MacroAssembler* masm_;  // to generate code

  CompilationInfo* info_;

  // Code generation state
  VirtualFrame* frame_;
  RegisterAllocator* allocator_;
  Condition cc_reg_;
  CodeGenState* state_;

  // Jump targets
  BreakTarget function_return_;

  // True if the function return is shadowed (ie, jumping to the target
  // function_return_ does not jump to the true function return, but rather
  // to some unlinking code).
  bool function_return_is_shadowed_;

  static InlineRuntimeLUT kInlineRuntimeLUT[];

  friend class VirtualFrame;
  friend class JumpTarget;
  friend class Reference;
  friend class FastCodeGenerator;
  friend class FullCodeGenerator;
  friend class FullCodeGenSyntaxChecker;

  DISALLOW_COPY_AND_ASSIGN(CodeGenerator);
};


} }  // namespace v8::internal

#endif  // V8_MIPS_CODEGEN_MIPS_H_