Clean up the nesting stack in the full code generator.

Remove unused methods, introduce named constants, and attempt to add some
sanity to naming.

BUG=
TEST=

Review URL: http://codereview.chromium.org/7669018

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@8972 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/arm/full-codegen-arm.cc

@@ -878,7 +878,7 @@ void FullCodeGenerator::VisitSwitchStatement(SwitchStatement* stmt) {
   __ bind(&next_test);
   __ Drop(1);  // Switch value is no longer needed.
   if (default_clause == NULL) {
-    __ b(nested_statement.break_target());
+    __ b(nested_statement.break_label());
   } else {
     __ b(default_clause->body_target());
   }
@@ -892,7 +892,7 @@ void FullCodeGenerator::VisitSwitchStatement(SwitchStatement* stmt) {
     VisitStatements(clause->statements());
   }
 
-  __ bind(nested_statement.break_target());
+  __ bind(nested_statement.break_label());
   PrepareForBailoutForId(stmt->ExitId(), NO_REGISTERS);
 }
 
@@ -1023,7 +1023,7 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
   // Load the current count to r0, load the length to r1.
   __ Ldrd(r0, r1, MemOperand(sp, 0 * kPointerSize));
   __ cmp(r0, r1);  // Compare to the array length.
-  __ b(hs, loop_statement.break_target());
+  __ b(hs, loop_statement.break_label());
 
   // Get the current entry of the array into register r3.
   __ ldr(r2, MemOperand(sp, 2 * kPointerSize));
@@ -1049,7 +1049,7 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
   __ push(r3);  // Current entry.
   __ InvokeBuiltin(Builtins::FILTER_KEY, CALL_FUNCTION);
   __ mov(r3, Operand(r0), SetCC);
-  __ b(eq, loop_statement.continue_target());
+  __ b(eq, loop_statement.continue_label());
 
   // Update the 'each' property or variable from the possibly filtered
   // entry in register r3.
@@ -1065,7 +1065,7 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
 
   // Generate code for the going to the next element by incrementing
   // the index (smi) stored on top of the stack.
-  __ bind(loop_statement.continue_target());
+  __ bind(loop_statement.continue_label());
   __ pop(r0);
   __ add(r0, r0, Operand(Smi::FromInt(1)));
   __ push(r0);
@@ -1074,7 +1074,7 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
   __ b(&loop);
 
   // Remove the pointers stored on the stack.
-  __ bind(loop_statement.break_target());
+  __ bind(loop_statement.break_label());
   __ Drop(5);
 
   // Exit and decrement the loop depth.

src/full-codegen.cc

@@ -862,7 +862,7 @@ void FullCodeGenerator::VisitBlock(Block* stmt) {
   PrepareForBailoutForId(stmt->EntryId(), NO_REGISTERS);
   VisitStatements(stmt->statements());
   scope_ = saved_scope;
-  __ bind(nested_statement.break_target());
+  __ bind(nested_statement.break_label());
   PrepareForBailoutForId(stmt->ExitId(), NO_REGISTERS);
 }
 
@@ -932,8 +932,7 @@ void FullCodeGenerator::VisitContinueStatement(ContinueStatement* stmt) {
                       context_register());
   }
 
-  Iteration* loop = current->AsIteration();
-  __ jmp(loop->continue_target());
+  __ jmp(current->AsIteration()->continue_label());
 }
 
 
@@ -961,8 +960,7 @@ void FullCodeGenerator::VisitBreakStatement(BreakStatement* stmt) {
                       context_register());
   }
 
-  Breakable* target = current->AsBreakable();
-  __ jmp(target->break_target());
+  __ jmp(current->AsBreakable()->break_label());
 }
 
 
@@ -1030,12 +1028,12 @@ void FullCodeGenerator::VisitDoWhileStatement(DoWhileStatement* stmt) {
 
   // Record the position of the do while condition and make sure it is
   // possible to break on the condition.
-  __ bind(loop_statement.continue_target());
+  __ bind(loop_statement.continue_label());
   PrepareForBailoutForId(stmt->ContinueId(), NO_REGISTERS);
   SetExpressionPosition(stmt->cond(), stmt->condition_position());
   VisitForControl(stmt->cond(),
                   &stack_check,
-                  loop_statement.break_target(),
+                  loop_statement.break_label(),
                   &stack_check);
 
   // Check stack before looping.
@@ -1045,7 +1043,7 @@ void FullCodeGenerator::VisitDoWhileStatement(DoWhileStatement* stmt) {
   __ jmp(&body);
 
   PrepareForBailoutForId(stmt->ExitId(), NO_REGISTERS);
-  __ bind(loop_statement.break_target());
+  __ bind(loop_statement.break_label());
   decrement_loop_depth();
 }
 
@@ -1066,7 +1064,7 @@ void FullCodeGenerator::VisitWhileStatement(WhileStatement* stmt) {
 
   // Emit the statement position here as this is where the while
   // statement code starts.
-  __ bind(loop_statement.continue_target());
+  __ bind(loop_statement.continue_label());
   SetStatementPosition(stmt);
 
   // Check stack before looping.
@@ -1075,11 +1073,11 @@ void FullCodeGenerator::VisitWhileStatement(WhileStatement* stmt) {
   __ bind(&test);
   VisitForControl(stmt->cond(),
                   &body,
-                  loop_statement.break_target(),
-                  loop_statement.break_target());
+                  loop_statement.break_label(),
+                  loop_statement.break_label());
 
   PrepareForBailoutForId(stmt->ExitId(), NO_REGISTERS);
-  __ bind(loop_statement.break_target());
+  __ bind(loop_statement.break_label());
   decrement_loop_depth();
 }
 
@@ -1102,7 +1100,7 @@ void FullCodeGenerator::VisitForStatement(ForStatement* stmt) {
   Visit(stmt->body());
 
   PrepareForBailoutForId(stmt->ContinueId(), NO_REGISTERS);
-  __ bind(loop_statement.continue_target());
+  __ bind(loop_statement.continue_label());
   SetStatementPosition(stmt);
   if (stmt->next() != NULL) {
     Visit(stmt->next());
@@ -1119,14 +1117,14 @@ void FullCodeGenerator::VisitForStatement(ForStatement* stmt) {
   if (stmt->cond() != NULL) {
     VisitForControl(stmt->cond(),
                     &body,
-                    loop_statement.break_target(),
-                    loop_statement.break_target());
+                    loop_statement.break_label(),
+                    loop_statement.break_label());
   } else {
     __ jmp(&body);
   }
 
   PrepareForBailoutForId(stmt->ExitId(), NO_REGISTERS);
-  __ bind(loop_statement.break_target());
+  __ bind(loop_statement.break_label());
   decrement_loop_depth();
 }
 
@@ -1144,7 +1142,7 @@ void FullCodeGenerator::VisitTryCatchStatement(TryCatchStatement* stmt) {
   // to introduce a new scope to bind the catch variable and to remove
   // that scope again afterwards.
 
-  Label try_handler_setup, catch_entry, done;
+  Label try_handler_setup, done;
   __ Call(&try_handler_setup);
   // Try handler code, exception in result register.
 
@@ -1170,12 +1168,13 @@ void FullCodeGenerator::VisitTryCatchStatement(TryCatchStatement* stmt) {
   // Try block code. Sets up the exception handler chain.
   __ bind(&try_handler_setup);
   {
-    TryCatch try_block(this, &catch_entry);
+    const int delta = StackHandlerConstants::kSize / kPointerSize;
+    TryCatch try_block(this);
     __ PushTryHandler(IN_JAVASCRIPT, TRY_CATCH_HANDLER);
-    increment_stack_height(StackHandlerConstants::kSize / kPointerSize);
+    increment_stack_height(delta);
     Visit(stmt->try_block());
     __ PopTryHandler();
-    decrement_stack_height(StackHandlerConstants::kSize / kPointerSize);
+    decrement_stack_height(delta);
   }
   __ bind(&done);
 }
@@ -1208,9 +1207,6 @@ void FullCodeGenerator::VisitTryFinallyStatement(TryFinallyStatement* stmt) {
   Label finally_entry;
   Label try_handler_setup;
   const int original_stack_height = stack_height();
-  const int finally_block_stack_height = original_stack_height + 2;
-  const int try_block_stack_height = original_stack_height + 5;
-  STATIC_ASSERT(StackHandlerConstants::kSize == 5 * kPointerSize);
 
   // Setup the try-handler chain. Use a call to
   // Jump to try-handler setup and try-block code. Use call to put try-handler
@@ -1219,9 +1215,9 @@ void FullCodeGenerator::VisitTryFinallyStatement(TryFinallyStatement* stmt) {
   // Try handler code. Return address of call is pushed on handler stack.
   {
     // This code is only executed during stack-handler traversal when an
-    // exception is thrown. The execption is in the result register, which
+    // exception is thrown. The exception is in the result register, which
     // is retained by the finally block.
-    // Call the finally block and then rethrow the exception.
+    // Call the finally block and then rethrow the exception if it returns.
     __ Call(&finally_entry);
     __ push(result_register());
     __ CallRuntime(Runtime::kReThrow, 1);
@@ -1232,7 +1228,7 @@ void FullCodeGenerator::VisitTryFinallyStatement(TryFinallyStatement* stmt) {
     // Finally block implementation.
     Finally finally_block(this);
     EnterFinallyBlock();
-    set_stack_height(finally_block_stack_height);
+    set_stack_height(original_stack_height + Finally::kElementCount);
     Visit(stmt->finally_block());
     ExitFinallyBlock();  // Return to the calling code.
   }
@@ -1240,9 +1236,10 @@ void FullCodeGenerator::VisitTryFinallyStatement(TryFinallyStatement* stmt) {
   __ bind(&try_handler_setup);
   {
     // Setup try handler (stack pointer registers).
+    const int delta = StackHandlerConstants::kSize / kPointerSize;
     TryFinally try_block(this, &finally_entry);
     __ PushTryHandler(IN_JAVASCRIPT, TRY_FINALLY_HANDLER);
-    set_stack_height(try_block_stack_height);
+    set_stack_height(original_stack_height + delta);
     Visit(stmt->try_block());
     __ PopTryHandler();
     set_stack_height(original_stack_height);

src/full-codegen.h

@@ -111,10 +111,7 @@ class FullCodeGenerator: public AstVisitor {
  private:
   class Breakable;
   class Iteration;
-  class TryCatch;
-  class TryFinally;
-  class Finally;
-  class ForIn;
+
   class TestContext;
 
   class NestedStatement BASE_EMBEDDED {
@@ -132,10 +129,6 @@ class FullCodeGenerator: public AstVisitor {
 
     virtual Breakable* AsBreakable() { return NULL; }
     virtual Iteration* AsIteration() { return NULL; }
-    virtual TryCatch* AsTryCatch() { return NULL; }
-    virtual TryFinally* AsTryFinally() { return NULL; }
-    virtual Finally* AsFinally() { return NULL; }
-    virtual ForIn* AsForIn() { return NULL; }
 
     virtual bool IsContinueTarget(Statement* target) { return false; }
     virtual bool IsBreakTarget(Statement* target) { return false; }
@@ -158,110 +151,102 @@ class FullCodeGenerator: public AstVisitor {
     DISALLOW_COPY_AND_ASSIGN(NestedStatement);
   };
 
+  // A breakable statement such as a block.
   class Breakable : public NestedStatement {
    public:
-    Breakable(FullCodeGenerator* codegen,
-              BreakableStatement* break_target)
-        : NestedStatement(codegen),
-          target_(break_target) {}
+    Breakable(FullCodeGenerator* codegen, BreakableStatement* statement)
+        : NestedStatement(codegen), statement_(statement) {
+    }
     virtual ~Breakable() {}
+
     virtual Breakable* AsBreakable() { return this; }
-    virtual bool IsBreakTarget(Statement* statement) {
-      return target_ == statement;
+    virtual bool IsBreakTarget(Statement* target) {
+      return statement() == target;
     }
-    BreakableStatement* statement() { return target_; }
-    Label* break_target() { return &break_target_label_; }
+
+    BreakableStatement* statement() { return statement_; }
+    Label* break_label() { return &break_label_; }
+
    private:
-    BreakableStatement* target_;
-    Label break_target_label_;
-    DISALLOW_COPY_AND_ASSIGN(Breakable);
+    BreakableStatement* statement_;
+    Label break_label_;
   };
 
+  // An iteration statement such as a while, for, or do loop.
   class Iteration : public Breakable {
    public:
-    Iteration(FullCodeGenerator* codegen,
-              IterationStatement* iteration_statement)
-        : Breakable(codegen, iteration_statement) {}
+    Iteration(FullCodeGenerator* codegen, IterationStatement* statement)
+        : Breakable(codegen, statement) {
+    }
     virtual ~Iteration() {}
+
     virtual Iteration* AsIteration() { return this; }
-    virtual bool IsContinueTarget(Statement* statement) {
-      return this->statement() == statement;
+    virtual bool IsContinueTarget(Statement* target) {
+      return statement() == target;
     }
-    Label* continue_target() { return &continue_target_label_; }
+
+    Label* continue_label() { return &continue_label_; }
+
    private:
-    Label continue_target_label_;
-    DISALLOW_COPY_AND_ASSIGN(Iteration);
+    Label continue_label_;
   };
 
-  // The environment inside the try block of a try/catch statement.
+  // The try block of a try/catch statement.
   class TryCatch : public NestedStatement {
    public:
-    explicit TryCatch(FullCodeGenerator* codegen, Label* catch_entry)
-        : NestedStatement(codegen), catch_entry_(catch_entry) { }
+    explicit TryCatch(FullCodeGenerator* codegen) : NestedStatement(codegen) {
+    }
     virtual ~TryCatch() {}
-    virtual TryCatch* AsTryCatch() { return this; }
-    Label* catch_entry() { return catch_entry_; }
+
     virtual NestedStatement* Exit(int* stack_depth, int* context_length);
-   private:
-    Label* catch_entry_;
-    DISALLOW_COPY_AND_ASSIGN(TryCatch);
   };
 
-  // The environment inside the try block of a try/finally statement.
+  // The try block of a try/finally statement.
   class TryFinally : public NestedStatement {
    public:
-    explicit TryFinally(FullCodeGenerator* codegen, Label* finally_entry)
-        : NestedStatement(codegen), finally_entry_(finally_entry) { }
+    TryFinally(FullCodeGenerator* codegen, Label* finally_entry)
+        : NestedStatement(codegen), finally_entry_(finally_entry) {
+    }
     virtual ~TryFinally() {}
-    virtual TryFinally* AsTryFinally() { return this; }
-    Label* finally_entry() { return finally_entry_; }
+
     virtual NestedStatement* Exit(int* stack_depth, int* context_length);
+
    private:
     Label* finally_entry_;
-    DISALLOW_COPY_AND_ASSIGN(TryFinally);
   };
 
-  // A FinallyEnvironment represents being inside a finally block.
-  // Abnormal termination of the finally block needs to clean up
-  // the block's parameters from the stack.
+  // The finally block of a try/finally statement.
   class Finally : public NestedStatement {
    public:
+    static const int kElementCount = 2;
+
     explicit Finally(FullCodeGenerator* codegen) : NestedStatement(codegen) { }
     virtual ~Finally() {}
-    virtual Finally* AsFinally() { return this; }
+
     virtual NestedStatement* Exit(int* stack_depth, int* context_length) {
-      *stack_depth += kFinallyStackElementCount;
+      *stack_depth += kElementCount;
       return previous_;
     }
-   private:
-    // Number of extra stack slots occupied during a finally block.
-    static const int kFinallyStackElementCount = 2;
-    DISALLOW_COPY_AND_ASSIGN(Finally);
   };
 
-  // A ForInEnvironment represents being inside a for-in loop.
-  // Abnormal termination of the for-in block needs to clean up
-  // the block's temporary storage from the stack.
+  // The body of a for/in loop.
   class ForIn : public Iteration {
    public:
-    ForIn(FullCodeGenerator* codegen,
-          ForInStatement* statement)
-        : Iteration(codegen, statement) { }
+    static const int kElementCount = 5;
+
+    ForIn(FullCodeGenerator* codegen, ForInStatement* statement)
+        : Iteration(codegen, statement) {
+    }
     virtual ~ForIn() {}
-    virtual ForIn* AsForIn() { return this; }
+
     virtual NestedStatement* Exit(int* stack_depth, int* context_length) {
-      *stack_depth += kForInStackElementCount;
+      *stack_depth += kElementCount;
       return previous_;
     }
-   private:
-    static const int kForInStackElementCount = 5;
-    DISALLOW_COPY_AND_ASSIGN(ForIn);
   };
 
 
-  // A WithOrCatch represents being inside the body of a with or catch
-  // statement.  Exiting the body needs to remove a link from the context
-  // chain.
+  // The body of a with or catch.
   class WithOrCatch : public NestedStatement {
    public:
     explicit WithOrCatch(FullCodeGenerator* codegen)

src/ia32/full-codegen-ia32.cc

@@ -875,7 +875,7 @@ void FullCodeGenerator::VisitSwitchStatement(SwitchStatement* stmt) {
   __ bind(&next_test);
   __ Drop(1);  // Switch value is no longer needed.
   if (default_clause == NULL) {
-    __ jmp(nested_statement.break_target());
+    __ jmp(nested_statement.break_label());
   } else {
     __ jmp(default_clause->body_target());
   }
@@ -890,7 +890,7 @@ void FullCodeGenerator::VisitSwitchStatement(SwitchStatement* stmt) {
     VisitStatements(clause->statements());
   }
 
-  __ bind(nested_statement.break_target());
+  __ bind(nested_statement.break_label());
   PrepareForBailoutForId(stmt->ExitId(), NO_REGISTERS);
 }
 
@@ -1006,12 +1006,13 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
   __ push(eax);  // Fixed array length (as smi).
   __ push(Immediate(Smi::FromInt(0)));  // Initial index.
 
-  increment_stack_height(4);
+  // 1 ~ The object has already been pushed.
+  increment_stack_height(ForIn::kElementCount - 1);
   // Generate code for doing the condition check.
   __ bind(&loop);
   __ mov(eax, Operand(esp, 0 * kPointerSize));  // Get the current index.
   __ cmp(eax, Operand(esp, 1 * kPointerSize));  // Compare to the array length.
-  __ j(above_equal, loop_statement.break_target());
+  __ j(above_equal, loop_statement.break_label());
 
   // Get the current entry of the array into register ebx.
   __ mov(ebx, Operand(esp, 2 * kPointerSize));
@@ -1035,7 +1036,7 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
   __ push(ebx);  // Current entry.
   __ InvokeBuiltin(Builtins::FILTER_KEY, CALL_FUNCTION);
   __ test(eax, Operand(eax));
-  __ j(equal, loop_statement.continue_target());
+  __ j(equal, loop_statement.continue_label());
   __ mov(ebx, Operand(eax));
 
   // Update the 'each' property or variable from the possibly filtered
@@ -1052,17 +1053,17 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
 
   // Generate code for going to the next element by incrementing the
   // index (smi) stored on top of the stack.
-  __ bind(loop_statement.continue_target());
+  __ bind(loop_statement.continue_label());
   __ add(Operand(esp, 0 * kPointerSize), Immediate(Smi::FromInt(1)));
 
   EmitStackCheck(stmt);
   __ jmp(&loop);
 
   // Remove the pointers stored on the stack.
-  __ bind(loop_statement.break_target());
+  __ bind(loop_statement.break_label());
   __ add(Operand(esp), Immediate(5 * kPointerSize));
 
-  decrement_stack_height(5);
+  decrement_stack_height(ForIn::kElementCount);
   // Exit and decrement the loop depth.
   __ bind(&exit);
   decrement_loop_depth();

src/x64/full-codegen-x64.cc

@@ -842,7 +842,7 @@ void FullCodeGenerator::VisitSwitchStatement(SwitchStatement* stmt) {
   __ bind(&next_test);
   __ Drop(1);  // Switch value is no longer needed.
   if (default_clause == NULL) {
-    __ jmp(nested_statement.break_target());
+    __ jmp(nested_statement.break_label());
   } else {
     __ jmp(default_clause->body_target());
   }
@@ -856,7 +856,7 @@ void FullCodeGenerator::VisitSwitchStatement(SwitchStatement* stmt) {
     VisitStatements(clause->statements());
   }
 
-  __ bind(nested_statement.break_target());
+  __ bind(nested_statement.break_label());
   PrepareForBailoutForId(stmt->ExitId(), NO_REGISTERS);
 }
 
@@ -982,7 +982,7 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
   __ bind(&loop);
   __ movq(rax, Operand(rsp, 0 * kPointerSize));  // Get the current index.
   __ cmpq(rax, Operand(rsp, 1 * kPointerSize));  // Compare to the array length.
-  __ j(above_equal, loop_statement.break_target());
+  __ j(above_equal, loop_statement.break_label());
 
   // Get the current entry of the array into register rbx.
   __ movq(rbx, Operand(rsp, 2 * kPointerSize));
@@ -1010,7 +1010,7 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
   __ push(rbx);  // Current entry.
   __ InvokeBuiltin(Builtins::FILTER_KEY, CALL_FUNCTION);
   __ Cmp(rax, Smi::FromInt(0));
-  __ j(equal, loop_statement.continue_target());
+  __ j(equal, loop_statement.continue_label());
   __ movq(rbx, rax);
 
   // Update the 'each' property or variable from the possibly filtered
@@ -1027,14 +1027,14 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
 
   // Generate code for going to the next element by incrementing the
   // index (smi) stored on top of the stack.
-  __ bind(loop_statement.continue_target());
+  __ bind(loop_statement.continue_label());
   __ SmiAddConstant(Operand(rsp, 0 * kPointerSize), Smi::FromInt(1));
 
   EmitStackCheck(stmt);
   __ jmp(&loop);
 
   // Remove the pointers stored on the stack.
-  __ bind(loop_statement.break_target());
+  __ bind(loop_statement.break_label());
   __ addq(rsp, Immediate(5 * kPointerSize));
 
   // Exit and decrement the loop depth.