Move backend specific files to separate directories.

src/ia32/codegen-ia32.h

+// Copyright 2006-2008 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// 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
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef V8_CODEGEN_IA32_H_
+#define V8_CODEGEN_IA32_H_
+
+namespace v8 { namespace internal {
+
+// Forward declarations
+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 { ILLEGAL = -1, SLOT = 0, NAMED = 1, KEYED = 2 };
+  Reference(CodeGenerator* cgen, Expression* expression);
+  ~Reference();
+
+  Expression* expression() const { return expression_; }
+  Type type() const { return type_; }
+  void set_type(Type value) {
+    ASSERT(type_ == ILLEGAL);
+    type_ = value;
+  }
+
+  // The size the reference takes up on the stack.
+  int size() const { return (type_ == ILLEGAL) ? 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; }
+
+  // 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 left in place with its value above it.
+  void GetValue(TypeofState typeof_state);
+
+  // Like GetValue except that the slot is expected to be written to before
+  // being read from again.  Thae value of the reference may be invalidated,
+  // causing subsequent attempts to read it to fail.
+  void TakeValue(TypeofState typeof_state);
+
+  // 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 stored value is left in place (with the
+  // reference intact below it) to support chained assignments.
+  void SetValue(InitState init_state);
+
+ private:
+  CodeGenerator* cgen_;
+  Expression* expression_;
+  Type type_;
+};
+
+
+// -------------------------------------------------------------------------
+// Control destinations.
+
+// A control destination encapsulates a pair of jump targets and a
+// flag indicating which one is the preferred fall-through.  The
+// preferred fall-through must be unbound, the other may be already
+// bound (ie, a backward target).
+//
+// The true and false targets may be jumped to unconditionally or
+// control may split conditionally.  Unconditional jumping and
+// splitting should be emitted in tail position (as the last thing
+// when compiling an expression) because they can cause either label
+// to be bound or the non-fall through to be jumped to leaving an
+// invalid virtual frame.
+//
+// The labels in the control destination can be extracted and
+// manipulated normally without affecting the state of the
+// destination.
+
+class ControlDestination BASE_EMBEDDED {
+ public:
+  ControlDestination(JumpTarget* true_target,
+                     JumpTarget* false_target,
+                     bool true_is_fall_through)
+      : true_target_(true_target),
+        false_target_(false_target),
+        true_is_fall_through_(true_is_fall_through),
+        is_used_(false) {
+    ASSERT(true_is_fall_through ? !true_target->is_bound()
+                                : !false_target->is_bound());
+  }
+
+  // Accessors for the jump targets.  Directly jumping or branching to
+  // or binding the targets will not update the destination's state.
+  JumpTarget* true_target() const { return true_target_; }
+  JumpTarget* false_target() const { return false_target_; }
+
+  // True if the the destination has been jumped to unconditionally or
+  // control has been split to both targets.  This predicate does not
+  // test whether the targets have been extracted and manipulated as
+  // raw jump targets.
+  bool is_used() const { return is_used_; }
+
+  // True if the destination is used and the true target (respectively
+  // false target) was the fall through.  If the target is backward,
+  // "fall through" included jumping unconditionally to it.
+  bool true_was_fall_through() const {
+    return is_used_ && true_is_fall_through_;
+  }
+
+  bool false_was_fall_through() const {
+    return is_used_ && !true_is_fall_through_;
+  }
+
+  // Emit a branch to one of the true or false targets, and bind the
+  // other target.  Because this binds the fall-through target, it
+  // should be emitted in tail position (as the last thing when
+  // compiling an expression).
+  void Split(Condition cc) {
+    ASSERT(!is_used_);
+    if (true_is_fall_through_) {
+      false_target_->Branch(NegateCondition(cc));
+      true_target_->Bind();
+    } else {
+      true_target_->Branch(cc);
+      false_target_->Bind();
+    }
+    is_used_ = true;
+  }
+
+  // Emit an unconditional jump in tail position, to the true target
+  // (if the argument is true) or the false target.  The "jump" will
+  // actually bind the jump target if it is forward, jump to it if it
+  // is backward.
+  void Goto(bool where) {
+    ASSERT(!is_used_);
+    JumpTarget* target = where ? true_target_ : false_target_;
+    if (target->is_bound()) {
+      target->Jump();
+    } else {
+      target->Bind();
+    }
+    is_used_ = true;
+    true_is_fall_through_ = where;
+  }
+
+  // Mark this jump target as used as if Goto had been called, but
+  // without generating a jump or binding a label (the control effect
+  // should have already happened).  This is used when the left
+  // subexpression of the short-circuit boolean operators are
+  // compiled.
+  void Use(bool where) {
+    ASSERT(!is_used_);
+    ASSERT((where ? true_target_ : false_target_)->is_bound());
+    is_used_ = true;
+    true_is_fall_through_ = where;
+  }
+
+  // Swap the true and false targets but keep the same actual label as
+  // the fall through.  This is used when compiling negated
+  // expressions, where we want to swap the targets but preserve the
+  // state.
+  void Invert() {
+    JumpTarget* temp_target = true_target_;
+    true_target_ = false_target_;
+    false_target_ = temp_target;
+
+    true_is_fall_through_ = !true_is_fall_through_;
+  }
+
+ private:
+  // True and false jump targets.
+  JumpTarget* true_target_;
+  JumpTarget* false_target_;
+
+  // Before using the destination: true if the true target is the
+  // preferred fall through, false if the false target is.  After
+  // using the destination: true if the true target was actually used
+  // as the fall through, false if the false target was.
+  bool true_is_fall_through_;
+
+  // True if the Split or Goto functions have been called.
+  bool is_used_;
+};
+
+
+// -------------------------------------------------------------------------
+// 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 jump target 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.
+//
+// The code generator state is only used for expressions, so statements have
+// the initial state.
+
+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 may or may not be inside a typeof, and has its
+  // own control destination.
+  CodeGenState(CodeGenerator* owner,
+               TypeofState typeof_state,
+               ControlDestination* destination);
+
+  // Destroy a code generator state and restore the owning code generator's
+  // previous state.
+  ~CodeGenState();
+
+  // Accessors for the state.
+  TypeofState typeof_state() const { return typeof_state_; }
+  ControlDestination* destination() const { return destination_; }
+
+ private:
+  // The owning code generator.
+  CodeGenerator* owner_;
+
+  // A flag indicating whether we are compiling the immediate subexpression
+  // of a typeof expression.
+  TypeofState typeof_state_;
+
+  // A control destination in case the expression has a control-flow
+  // effect.
+  ControlDestination* destination_;
+
+  // The previous state of the owning code generator, restored when
+  // this state is destroyed.
+  CodeGenState* previous_;
+};
+
+
+
+
+// -------------------------------------------------------------------------
+// CodeGenerator
+
+class CodeGenerator: public AstVisitor {
+ public:
+  // Takes a function literal, generates code for it. This function should only
+  // be called by compiler.cc.
+  static Handle<Code> MakeCode(FunctionLiteral* fun,
+                               Handle<Script> script,
+                               bool is_eval);
+
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  static bool ShouldGenerateLog(Expression* type);
+#endif
+
+  static void SetFunctionInfo(Handle<JSFunction> fun,
+                              int length,
+                              int function_token_position,
+                              int start_position,
+                              int end_position,
+                              bool is_expression,
+                              bool is_toplevel,
+                              Handle<Script> script,
+                              Handle<String> inferred_name);
+
+  // Accessors
+  MacroAssembler* masm() { return masm_; }
+
+  VirtualFrame* frame() const { return frame_; }
+
+  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); }
+
+  bool in_spilled_code() const { return in_spilled_code_; }
+  void set_in_spilled_code(bool flag) { in_spilled_code_ = flag; }
+
+ private:
+  // Construction/Destruction
+  CodeGenerator(int buffer_size, Handle<Script> script, bool is_eval);
+  virtual ~CodeGenerator() { delete masm_; }
+
+  // Accessors
+  Scope* scope() const { return scope_; }
+
+  // Clearing and generating deferred code.
+  void ClearDeferred();
+  void ProcessDeferred();
+
+  bool is_eval() { return is_eval_; }
+
+  // State
+  TypeofState typeof_state() const { return state_->typeof_state(); }
+  ControlDestination* destination() const { return state_->destination(); }
+
+  // Track loop nesting level.
+  int loop_nesting() const { return loop_nesting_; }
+  void IncrementLoopNesting() { loop_nesting_++; }
+  void DecrementLoopNesting() { loop_nesting_--; }
+
+
+  // Node visitors.
+  void VisitStatements(ZoneList<Statement*>* statements);
+
+#define DEF_VISIT(type) \
+  void Visit##type(type* node);
+  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.
+  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.
+  void VisitStatementsAndSpill(ZoneList<Statement*>* statements);
+
+  // Main code generation function
+  void GenCode(FunctionLiteral* fun);
+
+  // Generate the return sequence code.  Should be called no more than
+  // once per compiled function, immediately after binding the return
+  // target (which can not be done more than once).
+  void GenerateReturnSequence(Result* return_value);
+
+  // The following are used by class Reference.
+  void LoadReference(Reference* ref);
+  void UnloadReference(Reference* ref);
+
+  Operand ContextOperand(Register context, int index) const {
+    return Operand(context, Context::SlotOffset(index));
+  }
+
+  Operand SlotOperand(Slot* slot, Register tmp);
+
+  Operand ContextSlotOperandCheckExtensions(Slot* slot,
+                                            Result tmp,
+                                            JumpTarget* slow);
+
+  // Expressions
+  Operand GlobalObject() const {
+    return ContextOperand(esi, Context::GLOBAL_INDEX);
+  }
+
+  void LoadCondition(Expression* x,
+                     TypeofState typeof_state,
+                     ControlDestination* destination,
+                     bool force_control);
+  void Load(Expression* x, TypeofState typeof_state = NOT_INSIDE_TYPEOF);
+  void LoadGlobal();
+  void LoadGlobalReceiver();
+
+  // 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.
+  void LoadAndSpill(Expression* expression,
+                    TypeofState typeof_state = NOT_INSIDE_TYPEOF);
+
+  // Read a value from a slot and leave it on top of the expression stack.
+  void LoadFromSlot(Slot* slot, TypeofState typeof_state);
+  Result LoadFromGlobalSlotCheckExtensions(Slot* slot,
+                                           TypeofState typeof_state,
+                                           JumpTarget* slow);
+
+  // Store the value on top of the expression stack into a slot, leaving the
+  // value in place.
+  void StoreToSlot(Slot* slot, InitState init_state);
+
+  // Special code for typeof expressions: Unfortunately, we must
+  // be careful when loading the expression in 'typeof'
+  // expressions. We are not allowed to throw reference errors for
+  // non-existing properties of the global object, so we must make it
+  // look like an explicit property access, instead of an access
+  // through the context chain.
+  void LoadTypeofExpression(Expression* x);
+
+  // Translate the value on top of the frame into control flow to the
+  // control destination.
+  void ToBoolean(ControlDestination* destination);
+
+  void GenericBinaryOperation(
+      Token::Value op,
+      SmiAnalysis* type,
+      OverwriteMode overwrite_mode);
+
+  // If possible, combine two constant smi values using op to produce
+  // a smi result, and push it on the virtual frame, all at compile time.
+  // Returns true if it succeeds.  Otherwise it has no effect.
+  bool FoldConstantSmis(Token::Value op, int left, int right);
+
+  // Emit code to perform a binary operation on a constant
+  // smi and a likely smi.  Consumes the Result *operand.
+  void ConstantSmiBinaryOperation(Token::Value op,
+                                  Result* operand,
+                                  Handle<Object> constant_operand,
+                                  SmiAnalysis* type,
+                                  bool reversed,
+                                  OverwriteMode overwrite_mode);
+
+  // Emit code to perform a binary operation on two likely smis.
+  // The code to handle smi arguments is produced inline.
+  // Consumes the Results *left and *right.
+  void LikelySmiBinaryOperation(Token::Value op,
+                                Result* left,
+                                Result* right,
+                                OverwriteMode overwrite_mode);
+
+  void Comparison(Condition cc,
+                  bool strict,
+                  ControlDestination* destination);
+
+  // To prevent long attacker-controlled byte sequences, integer constants
+  // from the JavaScript source are loaded in two parts if they are larger
+  // than 16 bits.
+  static const int kMaxSmiInlinedBits = 16;
+  bool IsUnsafeSmi(Handle<Object> value);
+  // Load an integer constant x into a register target using
+  // at most 16 bits of user-controlled data per assembly operation.
+  void LoadUnsafeSmi(Register target, Handle<Object> value);
+
+  void CallWithArguments(ZoneList<Expression*>* arguments, int position);
+
+  void CheckStack();
+
+  bool CheckForInlineRuntimeCall(CallRuntime* node);
+  Handle<JSFunction> BuildBoilerplate(FunctionLiteral* node);
+  void ProcessDeclarations(ZoneList<Declaration*>* declarations);
+
+  Handle<Code> ComputeCallInitialize(int argc);
+  Handle<Code> ComputeCallInitializeInLoop(int argc);
+
+  // Declare global variables and functions in the given array of
+  // name/value pairs.
+  void DeclareGlobals(Handle<FixedArray> pairs);
+
+  // Instantiate the function boilerplate.
+  void InstantiateBoilerplate(Handle<JSFunction> boilerplate);
+
+  // Support for type checks.
+  void GenerateIsSmi(ZoneList<Expression*>* args);
+  void GenerateIsNonNegativeSmi(ZoneList<Expression*>* args);
+  void GenerateIsArray(ZoneList<Expression*>* args);
+
+  // Support for arguments.length and arguments[?].
+  void GenerateArgumentsLength(ZoneList<Expression*>* args);
+  void GenerateArgumentsAccess(ZoneList<Expression*>* args);
+
+  // Support for accessing the value field of an object (used by Date).
+  void GenerateValueOf(ZoneList<Expression*>* args);
+  void GenerateSetValueOf(ZoneList<Expression*>* args);
+
+  // Fast support for charCodeAt(n).
+  void GenerateFastCharCodeAt(ZoneList<Expression*>* args);
+
+  // Fast support for object equality testing.
+  void GenerateObjectEquals(ZoneList<Expression*>* args);
+
+  void GenerateLog(ZoneList<Expression*>* args);
+
+
+  // Methods and constants for fast case switch statement support.
+  //
+  // Only allow fast-case switch if the range of labels is at most
+  // this factor times the number of case labels.
+  // Value is derived from comparing the size of code generated by the normal
+  // switch code for Smi-labels to the size of a single pointer. If code
+  // quality increases this number should be decreased to match.
+  static const int kFastSwitchMaxOverheadFactor = 5;
+
+  // Minimal number of switch cases required before we allow jump-table
+  // optimization.
+  static const int kFastSwitchMinCaseCount = 5;
+
+  // The limit of the range of a fast-case switch, as a factor of the number
+  // of cases of the switch. Each platform should return a value that
+  // is optimal compared to the default code generated for a switch statement
+  // on that platform.
+  int FastCaseSwitchMaxOverheadFactor();
+
+  // The minimal number of cases in a switch before the fast-case switch
+  // optimization is enabled. Each platform should return a value that
+  // is optimal compared to the default code generated for a switch statement
+  // on that platform.
+  int FastCaseSwitchMinCaseCount();
+
+  // Allocate a jump table and create code to jump through it.
+  // Should call GenerateFastCaseSwitchCases to generate the code for
+  // all the cases at the appropriate point.
+  void GenerateFastCaseSwitchJumpTable(SwitchStatement* node,
+                                       int min_index,
+                                       int range,
+                                       Label* fail_label,
+                                       Vector<Label*> case_targets,
+                                       Vector<Label> case_labels);
+
+  // Generate the code for cases for the fast case switch.
+  // Called by GenerateFastCaseSwitchJumpTable.
+  void GenerateFastCaseSwitchCases(SwitchStatement* node,
+                                   Vector<Label> case_labels,
+                                   VirtualFrame* start_frame);
+
+  // Fast support for constant-Smi switches.
+  void GenerateFastCaseSwitchStatement(SwitchStatement* node,
+                                       int min_index,
+                                       int range,
+                                       int default_index);
+
+  // Fast support for constant-Smi switches. Tests whether switch statement
+  // permits optimization and calls GenerateFastCaseSwitch if it does.
+  // Returns true if the fast-case switch was generated, and false if not.
+  bool TryGenerateFastCaseSwitchStatement(SwitchStatement* node);
+
+  // 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(Node* node);
+  void CodeForSourcePosition(int pos);
+
+#ifdef DEBUG
+  // True if the registers are valid for entry to a block.  There should be
+  // no frame-external references to eax, ebx, ecx, edx, or edi.
+  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
+
+  // Code generation state
+  Scope* scope_;
+  VirtualFrame* frame_;
+  RegisterAllocator* allocator_;
+  CodeGenState* state_;
+  int loop_nesting_;
+
+  // Jump targets.
+  // The target of the return from the function.
+  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_;
+
+  // True when we are in code that expects the virtual frame to be fully
+  // spilled.  Some virtual frame function are disabled in DEBUG builds when
+  // called from spilled code, because they do not leave the virtual frame
+  // in a spilled state.
+  bool in_spilled_code_;
+
+  friend class VirtualFrame;
+  friend class JumpTarget;
+  friend class Reference;
+  friend class Result;
+
+  DISALLOW_COPY_AND_ASSIGN(CodeGenerator);
+};
+
+
+} }  // namespace v8::internal
+
+#endif  // V8_CODEGEN_IA32_H_