[fullcodegen] Implement control flow across do-expressions.

src/full-codegen/full-codegen.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_FULL_CODEGEN_FULL_CODEGEN_H_
 #define V8_FULL_CODEGEN_FULL_CODEGEN_H_
 
 #include "src/allocation.h"
 #include "src/assert-scope.h"
 #include "src/ast/ast.h"
@@ skipping 90 matching lines @@
 
  private:
   class Breakable;
   class Iteration;
   class TryFinally;
 
   class TestContext;
 
   class NestedStatement BASE_EMBEDDED {
    public:
-    explicit NestedStatement(FullCodeGenerator* codegen) : codegen_(codegen) {
+    explicit NestedStatement(FullCodeGenerator* codegen)
+        : codegen_(codegen),
+          stack_depth_at_target_(codegen->operand_stack_depth_) {
       // Link into codegen's nesting stack.
       previous_ = codegen->nesting_stack_;
       codegen->nesting_stack_ = this;
     }
     virtual ~NestedStatement() {
       // Unlink from codegen's nesting stack.
       DCHECK_EQ(this, codegen_->nesting_stack_);
       codegen_->nesting_stack_ = previous_;
     }
 
     virtual Breakable* AsBreakable() { return nullptr; }
     virtual Iteration* AsIteration() { return nullptr; }
     virtual TryFinally* AsTryFinally() { return nullptr; }
 
     virtual bool IsContinueTarget(Statement* target) { return false; }
     virtual bool IsBreakTarget(Statement* target) { return false; }
     virtual bool IsTryFinally() { return false; }
 
     // Notify the statement that we are exiting it via break, continue, or
     // return and give it a chance to generate cleanup code.  Return the
     // next outer statement in the nesting stack.  We accumulate in
-    // *stack_depth the amount to drop the stack and in *context_length the
-    // number of context chain links to unwind as we traverse the nesting
-    // stack from an exit to its target.
-    virtual NestedStatement* Exit(int* stack_depth, int* context_length) {
-      return previous_;
-    }
+    // {*context_length} the number of context chain links to unwind as we
+    // traverse the nesting stack from an exit to its target.
+    virtual NestedStatement* Exit(int* context_length) { return previous_; }
+
+    // Determine the expected operand stack depth when this statement is being
+    // used as the target of an exit. The caller will drop to this depth.
+    int GetStackDepthAtTarget() { return stack_depth_at_target_; }
 
    protected:
     MacroAssembler* masm() { return codegen_->masm(); }
 
     FullCodeGenerator* codegen_;
     NestedStatement* previous_;
+    int stack_depth_at_target_;
 
    private:
     DISALLOW_COPY_AND_ASSIGN(NestedStatement);
   };
 
   // A breakable statement such as a block.
   class Breakable : public NestedStatement {
    public:
     Breakable(FullCodeGenerator* codegen, BreakableStatement* statement)
         : NestedStatement(codegen), statement_(statement) {
@@ skipping 30 matching lines @@
     Label continue_label_;
   };
 
   // A nested block statement.
   class NestedBlock : public Breakable {
    public:
     NestedBlock(FullCodeGenerator* codegen, Block* block)
         : Breakable(codegen, block) {
     }
 
-    NestedStatement* Exit(int* stack_depth, int* context_length) override {
+    NestedStatement* Exit(int* context_length) override {
       auto block_scope = statement()->AsBlock()->scope();
       if (block_scope != nullptr) {
         if (block_scope->ContextLocalCount() > 0) ++(*context_length);
       }
       return previous_;
     }
   };
 
-  // The try block of a try/catch statement.
-  class TryCatch : public NestedStatement {
-   public:
-    static const int kElementCount = TryBlockConstant::kElementCount;
-
-    explicit TryCatch(FullCodeGenerator* codegen) : NestedStatement(codegen) {}
-
-    NestedStatement* Exit(int* stack_depth, int* context_length) override {
-      *stack_depth += kElementCount;
-      return previous_;
-    }
-  };
-
   class DeferredCommands {
    public:
     enum Command { kReturn, kThrow, kBreak, kContinue };
     typedef int TokenId;
     struct DeferredCommand {
       Command command;
       TokenId token;
       Statement* target;
     };
 
@@ skipping 20 matching lines @@
     ZoneVector<DeferredCommand> commands_;
     TokenDispenserForFinally dispenser_;
     TokenId return_token_;
     TokenId throw_token_;
     Label* finally_entry_;
   };
 
   // The try block of a try/finally statement.
   class TryFinally : public NestedStatement {
    public:
-    static const int kElementCount = TryBlockConstant::kElementCount;
-
     TryFinally(FullCodeGenerator* codegen, DeferredCommands* commands)
         : NestedStatement(codegen), deferred_commands_(commands) {}
 
-    NestedStatement* Exit(int* stack_depth, int* context_length) override;
+    NestedStatement* Exit(int* context_length) override;
 
     bool IsTryFinally() override { return true; }
     TryFinally* AsTryFinally() override { return this; }
 
     DeferredCommands* deferred_commands() { return deferred_commands_; }
 
    private:
     DeferredCommands* deferred_commands_;
   };
 
-  // The finally block of a try/finally statement.
-  class Finally : public NestedStatement {
-   public:
-    static const int kElementCount = 3;
-
-    explicit Finally(FullCodeGenerator* codegen) : NestedStatement(codegen) {}
-
-    NestedStatement* Exit(int* stack_depth, int* context_length) override {
-      *stack_depth += kElementCount;
-      return previous_;
-    }
-  };
-
-  // The body of a for/in loop.
-  class ForIn : public Iteration {
-   public:
-    static const int kElementCount = 5;
-
-    ForIn(FullCodeGenerator* codegen, ForInStatement* statement)
-        : Iteration(codegen, statement) {
-    }
-
-    NestedStatement* Exit(int* stack_depth, int* context_length) override {
-      *stack_depth += kElementCount;
-      return previous_;
-    }
-  };
-
-
   // The body of a with or catch.
   class WithOrCatch : public NestedStatement {
    public:
     explicit WithOrCatch(FullCodeGenerator* codegen)
         : NestedStatement(codegen) {
     }
 
-    NestedStatement* Exit(int* stack_depth, int* context_length) override {
+    NestedStatement* Exit(int* context_length) override {
       ++(*context_length);
       return previous_;
     }
   };
 
   // A platform-specific utility to overwrite the accumulator register
   // with a GC-safe value.
   void ClearAccumulator();
 
   // Determine whether or not to inline the smi case for the given
@@ skipping 777 matching lines @@
   Address start_;
   Address instruction_start_;
   uint32_t length_;
 };
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_FULL_CODEGEN_FULL_CODEGEN_H_