AmigActive 20/AACD20.BIN/AACD/Programming/Jikes/Source/src/body.cpp

C/C++ Source or Header | 2001-02-24 | 97.3 KB | 2,362 lines

// $Id: body.cpp,v 1.34 2001/02/18 23:21:18 mdejong Exp $
//
// This software is subject to the terms of the IBM Jikes Compiler
// License Agreement available at the following URL:
// http://www.ibm.com/research/jikes.
// Copyright (C) 1996, 1998, International Business Machines Corporation
// and others.  All Rights Reserved.
// You must accept the terms of that agreement to use this software.
//

#include "platform.h"
#include "semantic.h"
#include "control.h"

#ifdef    HAVE_JIKES_NAMESPACE
namespace Jikes {    // Open namespace Jikes block
#endif

void Semantic::ProcessBlockStatements(AstBlock *block_body)
{
    //
    // An empty block that is not a switch block can complete normally
    // iff it is reachable. A nonempty block that is not a switch
    // block can complete normally iff the last statement in it can
    // complete normally.
    //
    if (block_body -> NumStatements() == 0)
         block_body -> can_complete_normally = block_body -> is_reachable;
    else
    {
        //
        // The first statement in a nonempty block that is not a
        // switch block is reachable iff the block is reachable.
        // Every other statement S in a nonempty block that is not a
        // switch block is reachable iff the statement preceeding S
        // can complete normally.
        //
        AstStatement *statement = (AstStatement *) block_body -> Statement(0);
        statement -> is_reachable = block_body -> is_reachable;
        AstStatement *first_unreachable_statement = (AstStatement *) (statement -> is_reachable ? NULL : statement);
        ProcessStatement(statement);
        for (int i = 1; i < block_body -> NumStatements(); i++)
        {
            AstStatement *previous_statement = statement;
            statement = (AstStatement *) block_body -> Statement(i);
            statement -> is_reachable = previous_statement -> can_complete_normally;
            if (! statement -> is_reachable && (first_unreachable_statement == NULL))
                first_unreachable_statement = statement;

            ProcessStatement(statement);
        }

        if (statement -> can_complete_normally)
            block_body -> can_complete_normally = true;

        //
        // If we have one or more unreachable statements that are contained in a
        // reachable block then issue message. (If the enclosing block is not reachable
        // the message will be issued later for the enclosing block.)
        //
        if (first_unreachable_statement && LocalBlockStack().TopBlock() -> is_reachable)
        {
            if (first_unreachable_statement == statement)
            {
                ReportSemError(SemanticError::UNREACHABLE_STATEMENT,
                               statement -> LeftToken(),
                               statement -> RightToken());
            }
            else
            {
                ReportSemError(SemanticError::UNREACHABLE_STATEMENTS,
                               first_unreachable_statement -> LeftToken(),
                               statement -> RightToken());
            }
        }

        //
        // If an enclosed block has a higher max_variable_index than the current block,
        // update max_variable_index in the current_block, accordingly.
        //
        BlockSymbol *block = block_body -> block_symbol;
        if (block -> max_variable_index < LocalBlockStack().TopMaxEnclosedVariableIndex())
            block -> max_variable_index = LocalBlockStack().TopMaxEnclosedVariableIndex();
    }

    return;
}


void Semantic::ProcessBlock(Ast *stmt)
{
    AstBlock *block_body = (AstBlock *) stmt;

    AstBlock *enclosing_block = LocalBlockStack().TopBlock();

    //
    // Guess that the number of elements will not exceed the number of statements + 3. The +3 takes into account
    // one label + one ForInit declaration and one extra something else.
    //
    int table_size = block_body -> NumStatements() + 3;
    BlockSymbol *block = LocalSymbolTable().Top() -> InsertBlockSymbol(table_size);
    //
    // enclosing_block is not present only when we are processing the block of a static initializer
    //
    block -> max_variable_index = (enclosing_block ? enclosing_block -> block_symbol -> max_variable_index : 1);
    LocalSymbolTable().Push(block -> Table());

    block_body -> block_symbol = block;
    block_body -> nesting_level = LocalBlockStack().Size();
    LocalBlockStack().Push(block_body);

    //
    // Note that in constructing the Ast, the parser encloses each
    // labeled statement in its own block. Therefore the declaration
    // of this label will not conflict with the declaration of another
    // label with the same name declared at the same nesting level.
    //
    // For example, the following sequence of statements is legal:
    //
    //     l: a = b;
    //     l: b = c;
    //
    for (int i = 0; i < block_body -> NumLabels(); i++)
    {
        NameSymbol *name_symbol = lex_stream -> NameSymbol(block_body -> Label(i));
        Symbol *symbol = NULL;
        for (SemanticEnvironment *env = state_stack.Top(); env; env = env -> previous)
        {
            symbol = env -> symbol_table.FindLabelSymbol(name_symbol);
            if (symbol)
                break;
        }

        if (symbol)
        {
            ReportSemError(SemanticError::DUPLICATE_LABEL,
                           block_body -> Label(i),
                           block_body -> Label(i),
                           name_symbol -> Name());
        }
        else
        {
            LabelSymbol *label = LocalSymbolTable().Top() -> InsertLabelSymbol(name_symbol);
            label -> block = block_body;
            label -> nesting_level = block_body -> nesting_level;
        }
    }

    ProcessBlockStatements(block_body);

    LocalBlockStack().Pop();
    LocalSymbolTable().Pop();

    //
    // Update the information for the block that immediately encloses the current block.
    //
    if (enclosing_block)
    {
        if (LocalBlockStack().TopMaxEnclosedVariableIndex() < block -> max_variable_index)
            LocalBlockStack().TopMaxEnclosedVariableIndex() = block -> max_variable_index;
    }

    block -> CompressSpace(); // space optimization

    return;
}


void Semantic::ProcessLocalVariableDeclarationStatement(Ast *stmt)
{
    AstLocalVariableDeclarationStatement *local_decl = (AstLocalVariableDeclarationStatement *) stmt;

    AstArrayType *array_type = local_decl -> type -> ArrayTypeCast();
    Ast *actual_type = (array_type ? array_type -> type : local_decl -> type);

    AccessFlags access_flags = ProcessLocalModifiers(local_decl);

    AstPrimitiveType *primitive_type = actual_type -> PrimitiveTypeCast();
    TypeSymbol *field_type = (primitive_type ? field_type = FindPrimitiveType(primitive_type) : MustFindType(actual_type));

    for (int i = 0; i < local_decl -> NumVariableDeclarators(); i++)
    {
        AstVariableDeclarator *variable_declarator = local_decl -> VariableDeclarator(i);
        AstVariableDeclaratorId *name = variable_declarator -> variable_declarator_name;
        NameSymbol *name_symbol = lex_stream -> NameSymbol(name -> identifier_token);

//
// TODO: Confirm that this new test is indeed the case. In 1.0, only the more restricted test below was necessary.
//
//        if (LocalSymbolTable().FindVariableSymbol(name_symbol))
//        {
//            ReportSemError(SemanticError::DUPLICATE_LOCAL_VARIABLE_DECLARATION,
//                           name -> identifier_token,
//                           name -> identifier_token,
//                           name_symbol -> Name());
//        }
//
        SemanticEnvironment *where_found;
        Tuple<VariableSymbol *> variables_found(2);
        SearchForVariableInEnvironment(variables_found, where_found, state_stack.Top(), name_symbol, name -> identifier_token);
        VariableSymbol *symbol = (variables_found.Length() > 0 ? variables_found[0] : (VariableSymbol *) NULL);
        if (symbol && symbol -> IsLocal())
        {
            ReportSemError(SemanticError::DUPLICATE_LOCAL_VARIABLE_DECLARATION,
                           name -> identifier_token,
                           name -> identifier_token,
                           name_symbol -> Name());
        }
        else
        {
            symbol = LocalSymbolTable().Top() -> InsertVariableSymbol(name_symbol);
            variable_declarator -> symbol = symbol;

            int num_dimensions = (array_type ? array_type -> NumBrackets() : 0) + name -> NumBrackets();
            if (num_dimensions == 0)
                 symbol -> SetType(field_type);
            else symbol -> SetType(field_type -> GetArrayType((Semantic *) this, num_dimensions));
            symbol -> SetFlags(access_flags);
            symbol -> SetOwner(ThisMethod());
            symbol -> declarator = variable_declarator;
            BlockSymbol *block = LocalBlockStack().TopBlock() -> block_symbol;
            symbol -> SetLocalVariableIndex(block -> max_variable_index++); // Assigning a local_variable_index to a variable
                                                                            // also marks it complete as a side-effect.
            if (control.IsDoubleWordType(symbol -> Type()))
                block -> max_variable_index++;

            if (variable_declarator -> variable_initializer_opt)
                 ProcessVariableInitializer(variable_declarator);
        }
    }

    //
    // A local variable declaration statement can complete normally
    // iff it is reachable.
    //
    local_decl -> can_complete_normally = local_decl -> is_reachable;

    return;
}


void Semantic::ProcessExpressionStatement(Ast *stmt)
{
    AstExpressionStatement *expression_statement = (AstExpressionStatement *) stmt;

    ProcessExpression(expression_statement -> expression);

    //
    // An expression statement can complete normally iff it is reachable.
    //
    expression_statement -> can_complete_normally = expression_statement -> is_reachable;

    return;
}


void Semantic::ProcessSynchronizedStatement(Ast *stmt)
{
    AstSynchronizedStatement *synchronized_statement = (AstSynchronizedStatement *) stmt;

    ProcessExpression(synchronized_statement -> expression);

    synchronized_statement -> block -> is_reachable = synchronized_statement -> is_reachable;

    if (synchronized_statement -> expression -> Type() -> Primitive())
    {
        ReportSemError(SemanticError::TYPE_NOT_REFERENCE,
                       synchronized_statement -> expression -> LeftToken(),
                       synchronized_statement -> expression -> RightToken(),
                       synchronized_statement -> expression -> Type() -> Name());
    }

    AstBlock *enclosing_block = LocalBlockStack().TopBlock(),
             *block_body = synchronized_statement -> block;

    //
    // "synchronized" blocks require two more local variable slots for synchronization,
    // plus one extra variable slot if the containing method returns a value, plus an
    // additional slot if the value returned is double or long.
    //
    BlockSymbol *enclosing_block_symbol = enclosing_block -> block_symbol;
    if (enclosing_block_symbol -> try_or_synchronized_variable_index == 0) // first such statement encountered in enclosing block?
    {
        enclosing_block_symbol -> try_or_synchronized_variable_index = enclosing_block_symbol -> max_variable_index;
        enclosing_block_symbol -> max_variable_index += 2;
        if (ThisMethod() -> Type() != control.void_type)
        {
             if (control.IsDoubleWordType(ThisMethod() -> Type()))
                  enclosing_block_symbol -> max_variable_index += 2;
             else enclosing_block_symbol -> max_variable_index += 1;
        }
    }

    //
    // Guess that the number of elements will not exceed the number of statements + 3.
    //
    BlockSymbol *block = LocalSymbolTable().Top() -> InsertBlockSymbol(block_body -> NumStatements() + 3);
    block -> max_variable_index = enclosing_block_symbol -> max_variable_index;
    LocalSymbolTable().Push(block -> Table());

    block_body -> block_symbol = block;
    block_body -> nesting_level = LocalBlockStack().Size();
    LocalBlockStack().Push(block_body);

    ProcessBlockStatements(block_body);

    LocalBlockStack().Pop();
    LocalSymbolTable().Pop();

    if (LocalBlockStack().TopMaxEnclosedVariableIndex() < block -> max_variable_index)
        LocalBlockStack().TopMaxEnclosedVariableIndex() = block -> max_variable_index;

    //
    // If the synchronized_statement is enclosed in a loop and it contains a reachable continue statement
    // then it may have already been marked as "can complete normally";
    //
    synchronized_statement -> can_complete_normally = synchronized_statement -> can_complete_normally ||
                                                      synchronized_statement -> block -> can_complete_normally;

    block -> CompressSpace(); // space optimization

    return;
}


void Semantic::ProcessIfStatement(Ast *stmt)
{
    AstIfStatement *if_statement = (AstIfStatement *) stmt;

    ProcessExpression(if_statement -> expression);

    if (if_statement -> expression -> Type() != control.no_type &&
        if_statement -> expression -> Type() != control.boolean_type)
    {
        ReportSemError(SemanticError::TYPE_NOT_BOOLEAN,
                       if_statement -> expression -> LeftToken(),
                       if_statement -> expression -> RightToken(),
                       if_statement -> expression -> Type() -> Name());
    }

    //
    // Recall that the parser ensures that the statements that appear in an if-statement
    // (both the true and false statement) are enclosed in a block.
    //
    if_statement -> true_statement -> is_reachable = if_statement -> is_reachable;
    ProcessBlock(if_statement -> true_statement);

    if (if_statement -> false_statement_opt)
    {
        if_statement -> false_statement_opt -> is_reachable = if_statement -> is_reachable;
        ProcessBlock(if_statement -> false_statement_opt);

        //
        // If the if_statement is enclosed in a loop and it contains a reachable continue statement
        // then it may have already been marked as "can complete normally";
        //
        if_statement -> can_complete_normally = if_statement -> can_complete_normally ||
                                                if_statement -> true_statement -> can_complete_normally ||
                                                if_statement -> false_statement_opt -> can_complete_normally;
    }
    else if_statement -> can_complete_normally = if_statement -> is_reachable;

    return;
}


void Semantic::ProcessWhileStatement(Ast *stmt)
{
    AstWhileStatement *while_statement = (AstWhileStatement *) stmt;

    //
    // Recall that each while statement is enclosed in a unique block by the parser
    //
    BreakableStatementStack().Push(LocalBlockStack().TopBlock());
    ContinuableStatementStack().Push(LocalBlockStack().TopBlock());

    AstStatement *enclosed_statement = while_statement -> statement;
    enclosed_statement -> is_reachable = while_statement -> is_reachable;

    ProcessExpression(while_statement -> expression);
    if (while_statement -> expression -> Type() == control.boolean_type)
    {
        if (while_statement -> expression -> IsConstant())
        {
            IntLiteralValue *literal = (IntLiteralValue *) while_statement -> expression -> value;
            if (! literal -> value)
            {
                 if (while_statement -> is_reachable)
                     while_statement -> can_complete_normally = true;
                 enclosed_statement -> is_reachable = false;
            }
        }
        else if (while_statement -> is_reachable)
             while_statement -> can_complete_normally = true;
    }
    else if (while_statement -> expression -> Type() != control.no_type)
    {
        ReportSemError(SemanticError::TYPE_NOT_BOOLEAN,
                       while_statement -> expression -> LeftToken(),
                       while_statement -> expression -> RightToken(),
                       while_statement -> expression -> Type() -> Name());
    }

    ProcessStatement(enclosed_statement);

    if ((! enclosed_statement -> is_reachable) && (while_statement -> is_reachable))
    {
        ReportSemError(SemanticError::UNREACHABLE_STATEMENT,
                       enclosed_statement -> LeftToken(),
                       enclosed_statement -> RightToken());
    }

    //
    // If the while statement contained a reachable break statement,
    // then the while statement can complete normally. It is marked
    // here only for completeness, as marking the enclosing block is
    // enough to propagate the proper information upward.
    //
    AstBlock *block_body = (AstBlock *) BreakableStatementStack().Top();
    if (block_body -> can_complete_normally)
        while_statement -> can_complete_normally = true;

    BreakableStatementStack().Pop();
    ContinuableStatementStack().Pop();

    return;
}


void Semantic::ProcessForStatement(Ast *stmt)
{
    AstForStatement *for_statement = (AstForStatement *) stmt;

    //
    // Note that in constructing the Ast, the parser encloses each
    // for-statement whose for-init-statements starts with a local
    // variable declaration in its own block. Therefore a redeclaration
    // of another local variable with the same name in a different loop
    // at the same nesting level will not cause any conflict.
    //
    // For example, the following sequence of statements is legal:
    //
    //     for (int i = 0; i < 10; i++);
    //     for (int i = 10; i < 20; i++);
    //
    for (int i = 0; i < for_statement -> NumForInitStatements(); i++)
        ProcessStatement(for_statement -> ForInitStatement(i));

    //
    // Recall that each for statement is enclosed in a unique block by the parser
    //
    BreakableStatementStack().Push(LocalBlockStack().TopBlock());
    ContinuableStatementStack().Push(LocalBlockStack().TopBlock());

    //
    // Assume that if the for_statement is reachable then its
    // contained statement is also reachable. If it turns out that the
    // condition (end) expression is a constant FALSE expression we will
    // change the assumption...
    //
    AstStatement *enclosed_statement = for_statement -> statement;
    enclosed_statement -> is_reachable = for_statement -> is_reachable;

    if (for_statement -> end_expression_opt)
    {
        ProcessExpression(for_statement -> end_expression_opt);
        if (for_statement -> end_expression_opt -> Type() == control.boolean_type)
        {
            if (for_statement -> end_expression_opt -> IsConstant())
            {
                IntLiteralValue *literal = (IntLiteralValue *) for_statement -> end_expression_opt -> value;
                if (! literal -> value)
                {
                     if (for_statement -> is_reachable)
                         for_statement -> can_complete_normally = true;
                     enclosed_statement -> is_reachable = false;
                }
            }
            else if (for_statement -> is_reachable)
                 for_statement -> can_complete_normally = true;
        }
        else if (for_statement -> end_expression_opt -> Type() != control.no_type)
        {
            ReportSemError(SemanticError::TYPE_NOT_BOOLEAN,
                           for_statement -> end_expression_opt -> LeftToken(),
                           for_statement -> end_expression_opt -> RightToken(),
                           for_statement -> end_expression_opt -> Type() -> Name());
        }
    }

    ProcessStatement(enclosed_statement);

    if ((! enclosed_statement -> is_reachable) && (for_statement -> is_reachable))
    {
        ReportSemError(SemanticError::UNREACHABLE_STATEMENT,
                       enclosed_statement -> LeftToken(),
                       enclosed_statement -> RightToken());
    }

    for (int j = 0; j < for_statement -> NumForUpdateStatements(); j++)
        ProcessExpressionStatement(for_statement -> ForUpdateStatement(j));

    //
    // If the for statement contained a reachable break statement,
    // then the for statement can complete normally. It is marked
    // here only for completeness, as marking the enclosing block is
    // enough to propagate the proper information upward.
    //
    AstBlock *block_body = (AstBlock *) BreakableStatementStack().Top();
    if (block_body -> can_complete_normally)
        for_statement -> can_complete_normally = true;

    BreakableStatementStack().Pop();
    ContinuableStatementStack().Pop();

    return;
}


void Semantic::ProcessSwitchStatement(Ast *stmt)
{
    AstSwitchStatement *switch_statement = (AstSwitchStatement *) stmt;

    AstBlock *enclosing_block = LocalBlockStack().TopBlock();

    //
    // We estimate a size for the switch symbol table based on the number of lines in it.
    //
    AstBlock *block_body = switch_statement -> switch_block;
    BlockSymbol *block = LocalSymbolTable().Top() -> InsertBlockSymbol();
    block -> max_variable_index = enclosing_block -> block_symbol -> max_variable_index;
    LocalSymbolTable().Push(block -> Table());

    block_body -> block_symbol = block;
    block_body -> nesting_level = LocalBlockStack().Size();
    LocalBlockStack().Push(block_body);
    BreakableStatementStack().Push(block_body);

    ProcessExpression(switch_statement -> expression);
    TypeSymbol *type = switch_statement -> expression -> Type();

    if (type != control.int_type  && type != control.short_type &&
        type != control.char_type && type != control.byte_type  && type != control.no_type)
    {
        ReportSemError(SemanticError::TYPE_NOT_VALID_FOR_SWITCH,
                       switch_statement -> expression -> LeftToken(),
                       switch_statement -> expression -> RightToken(),
                       type -> ContainingPackage() -> PackageName(),
                       type -> ExternalName());
    }

    switch_statement -> default_case.switch_block_statement = NULL;

    //
    // Count the number case labels in this switch statement
    //
    int num_case_labels = 0;
    for (int i = 0; i < block_body -> NumStatements(); i++)
    {
        AstSwitchBlockStatement *switch_block_statement = (AstSwitchBlockStatement *) block_body -> Statement(i);
        num_case_labels += switch_block_statement -> NumSwitchLabels();
    }
    switch_statement -> AllocateCases(num_case_labels);

    //
    // A switch block is reachable iff its switch statement is reachable.
    //
    block_body -> is_reachable = switch_statement -> is_reachable;
    for (int j = 0; j < block_body -> NumStatements(); j++)
    {
        AstSwitchBlockStatement *switch_block_statement = (AstSwitchBlockStatement *) block_body -> Statement(j);

        for (int k = 0; k < switch_block_statement -> NumSwitchLabels(); k++)
        {
            AstCaseLabel *case_label = switch_block_statement -> SwitchLabel(k) -> CaseLabelCast();

            if (case_label)
            {
                ProcessExpression(case_label -> expression);

                if (case_label -> expression -> Type() != control.no_type)
                {
                    if (! case_label -> expression -> IsConstant())
                    {
                        ReportSemError(SemanticError::EXPRESSION_NOT_CONSTANT,
                                       case_label -> expression -> LeftToken(),
                                       case_label -> expression -> RightToken());
                        case_label -> expression -> symbol = control.no_type;
                    }
                    else if (type != control.no_type)
                    {
                        if (CanAssignmentConvert(type, case_label -> expression))
                        {
                            if (case_label -> expression -> Type() != type)
                                case_label -> expression = ConvertToType(case_label -> expression, type);

                            case_label -> map_index = switch_statement -> NumCases();

                            CaseElement *case_element = compilation_unit -> ast_pool -> GenCaseElement();
                            switch_statement -> AddCase(case_element);

                            case_element -> expression = case_label -> expression;
                            case_element -> switch_block_statement = switch_block_statement;
                            case_element -> index = case_label -> map_index; // use this index to keep sort stable !
                        }
                        else if (case_label -> expression -> Type() == control.int_type &&
                                 ! IsIntValueRepresentableInType(case_label -> expression, type))
                        {
                            IntToWstring value(((IntLiteralValue *) (case_label -> expression -> value)) -> value);

                            ReportSemError(SemanticError::VALUE_NOT_REPRESENTABLE_IN_SWITCH_TYPE,
                                           case_label -> expression -> LeftToken(),
                                           case_label -> expression -> RightToken(),
                                           value.String(),
                                           type -> Name());
                        }
                        else
                        {
                            ReportSemError(SemanticError::TYPE_NOT_CONVERTIBLE_TO_SWITCH_TYPE,
                                           case_label -> expression -> LeftToken(),
                                           case_label -> expression -> RightToken(),
                                           case_label -> expression -> Type() -> Name(),
                                           type -> Name());
                        }
                    }
                }
            }
            else if (switch_statement -> default_case.switch_block_statement == NULL)
                switch_statement -> default_case.switch_block_statement = switch_block_statement;
            else
            {
                ReportSemError(SemanticError::MULTIPLE_DEFAULT_LABEL,
                               ((AstDefaultLabel *) switch_block_statement -> SwitchLabel(k)) -> LeftToken(),
                               ((AstDefaultLabel *) switch_block_statement -> SwitchLabel(k)) -> RightToken());
            }
        }

        //
        // The parser ensures that a switch block statement always has one statement.
        // When a switch block ends with a sequence of switch labels that are not followed
        // by any executable statements, an artificial "empty" statement is added by the parser.
        //
        assert(switch_block_statement -> NumStatements() > 0);

        //
        // A statement in a switch block is reachable iff its
        // switch statement is reachable and at least one of the
        // following is true:
        //
        // . it bears a case or default label
        // . there is a statement preceeding it in the switch block and that
        // preceeding  statement can compile normally.
        //
        AstStatement *statement = (AstStatement *) switch_block_statement -> Statement(0);
        statement -> is_reachable = switch_statement -> is_reachable;
        AstStatement *first_unreachable_statement = (AstStatement *) (statement -> is_reachable ? NULL : statement);
        ProcessStatement(statement);
        for (int j = 1; j < switch_block_statement -> NumStatements(); j++)
        {
            AstStatement *previous_statement = statement;
            statement = (AstStatement *) switch_block_statement -> Statement(j);
            if (switch_statement -> is_reachable)
            {
                statement -> is_reachable = previous_statement -> can_complete_normally;
                if ((! statement -> is_reachable) && (first_unreachable_statement == NULL))
                    first_unreachable_statement = statement;
            }

            ProcessStatement(statement);
        }

        if (first_unreachable_statement)
        {
            if (first_unreachable_statement == statement)
            {
                ReportSemError(SemanticError::UNREACHABLE_STATEMENT,
                               statement -> LeftToken(),
                               statement -> RightToken());
            }
            else
            {
                ReportSemError(SemanticError::UNREACHABLE_STATEMENTS,
                               first_unreachable_statement -> LeftToken(),
                               statement -> RightToken());
            }
        }
    }

    //
    // A switch statement can complete normally iff at least one of the
    // following is true:
    //
    // . there is a reachable break statement that exits the switch
    //   statement. (See ProcessBreakStatement)
    // . the switch block is empty or contains only switch labels
    //   //
    //   // TODO: This statement seems to be erroneous. The proper statement
    //   //       as implemented here is:
    //   //
    //   //           . the switch block is empty or contains only case labels
    //   //
    // . there is at least one switch label after the last switch block
    //   statement group.
    // . the last statement in the switch block can complete normally
    //
    if (block_body -> can_complete_normally)
        switch_statement -> can_complete_normally = true;
    else if (switch_statement -> default_case.switch_block_statement == NULL)
        switch_statement -> can_complete_normally = true;
    else
    {
        AstSwitchBlockStatement *last_switch_block_statement = (AstSwitchBlockStatement *)
                                                               block_body -> Statement(block_body -> NumStatements() - 1);

        assert(last_switch_block_statement -> NumStatements() > 0);

        AstStatement *last_statement = (AstStatement *)
                                       last_switch_block_statement -> Statement(last_switch_block_statement -> NumStatements() - 1);
        if (last_statement -> can_complete_normally)
            switch_statement -> can_complete_normally = true;
    }

    switch_statement -> SortCases();
    for (int k = 1; k < switch_statement -> NumCases(); k++)
    {
        if (switch_statement -> Case(k) -> Value() == switch_statement -> Case(k - 1) -> Value())
        {
            IntToWstring value(switch_statement -> Case(k) -> Value());

            ReportSemError(SemanticError::DUPLICATE_CASE_VALUE,
                           switch_statement -> Case(k) -> expression -> LeftToken(),
                           switch_statement -> Case(k) -> expression -> RightToken(),
                           value.String());
        }
    }

    //
    // If an enclosed block has a higher max_variable_index than the current block,
    // update max_variable_index in the current_block, accordingly.
    // Also, update the information for the block that immediately encloses the current block.
    //
    if (block -> max_variable_index < LocalBlockStack().TopMaxEnclosedVariableIndex())
        block -> max_variable_index = LocalBlockStack().TopMaxEnclosedVariableIndex();

    BreakableStatementStack().Pop();
    LocalBlockStack().Pop();
    LocalSymbolTable().Pop();

    if (enclosing_block)
    {
        if (LocalBlockStack().TopMaxEnclosedVariableIndex() < block -> max_variable_index)
            LocalBlockStack().TopMaxEnclosedVariableIndex() = block -> max_variable_index;
    }

    block -> CompressSpace(); // space optimization

    return;
}


void Semantic::ProcessDoStatement(Ast *stmt)
{
    AstDoStatement *do_statement = (AstDoStatement *) stmt;

    //
    // Recall that each Do statement is enclosed in a unique block by the parser
    //
    BreakableStatementStack().Push(LocalBlockStack().TopBlock());
    ContinuableStatementStack().Push(LocalBlockStack().TopBlock());

    AstStatement *enclosed_statement = do_statement -> statement;
    enclosed_statement -> is_reachable = do_statement -> is_reachable;

    ProcessStatement(enclosed_statement);

    ProcessExpression(do_statement -> expression);

    IntLiteralValue *literal = NULL;
    if (do_statement -> expression -> Type() == control.boolean_type)
    {
        if (do_statement -> expression -> IsConstant())
            literal = (IntLiteralValue *) do_statement -> expression -> value;
    }
    else if (do_statement -> expression -> Type() != control.no_type)
    {
        ReportSemError(SemanticError::TYPE_NOT_BOOLEAN,
                       do_statement -> expression -> LeftToken(),
                       do_statement -> expression -> RightToken(),
                       do_statement -> expression -> Type() -> Name());
    }

    //
    // A do statement can complete normally, iff at least one of the following is true:
    //     1. The contained statement can complete normally and the condition expression
    //        is not a constant expression with the value true
    //     2. There is a reachable break statement that exits the do statement
    //        (This condition is true is the block that immediately encloses this do statement
    //         can complete normally. See ProcessBreakStatement)
    //
    AstBlock *block_body = (AstBlock *) BreakableStatementStack().Top();
    do_statement -> can_complete_normally = (enclosed_statement -> can_complete_normally && ((! literal) || literal -> value == 0)) ||
                                            block_body -> can_complete_normally;

    BreakableStatementStack().Pop();
    ContinuableStatementStack().Pop();

    return;
}


void Semantic::ProcessBreakStatement(Ast *stmt)
{
    AstBreakStatement *break_statement = (AstBreakStatement *) stmt;

    //
    // Recall that it is possible to break out of any labeled statement even if it is not a
    // do, for, while or switch statement.
    //
    if (break_statement -> identifier_token_opt)
    {
        NameSymbol *name_symbol = lex_stream -> NameSymbol(break_statement -> identifier_token_opt);
        LabelSymbol *label_symbol = LocalSymbolTable().FindLabelSymbol(name_symbol);

        if (label_symbol)
        {
            break_statement -> nesting_level = label_symbol -> nesting_level;
            AstBlock *block_body = label_symbol -> block;
            //
            // A labeled statement can complete normally if there is a
            // reachable break statement that exits the labeled statement.
            //
            if (block_body && break_statement -> is_reachable)
                block_body -> can_complete_normally = true;
        }
        else
        {
            AstBlock *block_body = (AstBlock *) LocalBlockStack().TopBlock();
            break_statement -> nesting_level = block_body -> nesting_level;
            ReportSemError(SemanticError::UNDECLARED_LABEL,
                           break_statement -> identifier_token_opt,
                           break_statement -> identifier_token_opt,
                           lex_stream -> NameString(break_statement -> identifier_token_opt));
        }
    }
    else
    {
        AstBlock *block_body = (AstBlock *) (BreakableStatementStack().Size() > 0 ? BreakableStatementStack().Top()
                                                                                  : LocalBlockStack().TopBlock());
        break_statement -> nesting_level = block_body -> nesting_level;
        if (BreakableStatementStack().Size() > 0)
        {
            if (break_statement -> is_reachable)
                block_body -> can_complete_normally = true;
        }
        else ReportSemError(SemanticError::MISPLACED_BREAK_STATEMENT,
                            break_statement -> LeftToken(),
                            break_statement -> RightToken());
    }

    return;
}


void Semantic::ProcessContinueStatement(Ast *stmt)
{
    AstContinueStatement *continue_statement = (AstContinueStatement *) stmt;

    //
    // The loop statement that is to be continued.
    //
    Ast *loop_statement = NULL;

    if (ContinuableStatementStack().Size() <= 0)
    {
        ReportSemError(SemanticError::MISPLACED_CONTINUE_STATEMENT,
                       continue_statement -> LeftToken(),
                       continue_statement -> RightToken());
    }
    else if (continue_statement -> identifier_token_opt)
    {
        NameSymbol *name_symbol = lex_stream -> NameSymbol(continue_statement -> identifier_token_opt);
        LabelSymbol *label_symbol = LocalSymbolTable().FindLabelSymbol(name_symbol);

        if (label_symbol)
        {
            continue_statement -> nesting_level = label_symbol -> nesting_level;

            assert(label_symbol -> block -> NumStatements() > 0);

            loop_statement = label_symbol -> block -> Statement(0);
        }
        else
        {
            AstBlock *block_body = (AstBlock *) LocalBlockStack().TopBlock();
            continue_statement -> nesting_level = block_body -> nesting_level;
            ReportSemError(SemanticError::UNDECLARED_LABEL,
                           continue_statement -> identifier_token_opt,
                           continue_statement -> identifier_token_opt,
                           lex_stream -> NameString(continue_statement -> identifier_token_opt));
        }
    }
    else
    {
        AstBlock *block_body = (AstBlock *) ContinuableStatementStack().Top();
        loop_statement = block_body -> Statement(0);
        continue_statement -> nesting_level = block_body -> nesting_level;
    }

    //
    // If this is a valid continue statement, it is associated with a loop statement.
    // Since the loop can be continued, its enclosed statement "can complete normally".
    //
    if (loop_statement)
    {
        AstDoStatement *do_statement = loop_statement -> DoStatementCast();
        AstForStatement *for_statement = loop_statement -> ForStatementCast();
        AstWhileStatement *while_statement = loop_statement -> WhileStatementCast();

        AstStatement *enclosed_statement = (do_statement ? do_statement -> statement
                                                         : (for_statement ? for_statement -> statement
                                                                          : (while_statement ? while_statement -> statement
                                                                                             : (AstStatement *) NULL)));
        if (enclosed_statement)
            enclosed_statement -> can_complete_normally = true;
        else
        {
            assert(continue_statement -> identifier_token_opt);

            ReportSemError(SemanticError::INVALID_CONTINUE_TARGET,
                           continue_statement -> LeftToken(),
                           continue_statement -> RightToken(),
                           lex_stream -> NameString(continue_statement -> identifier_token_opt));
        }
    }

    return;
}


void Semantic::ProcessReturnStatement(Ast *stmt)
{
    AstReturnStatement *return_statement = (AstReturnStatement *) stmt;

    MethodSymbol *this_method = ThisMethod();

    if (this_method -> name_symbol == control.clinit_name_symbol || this_method -> name_symbol == control.block_init_name_symbol)
    {
        ReportSemError(SemanticError::RETURN_STATEMENT_IN_INITIALIZER,
                       return_statement -> LeftToken(),
                       return_statement -> RightToken());
    }
    else if (return_statement -> expression_opt)
    {
        ProcessExpression(return_statement -> expression_opt);

        if (this_method -> Type() == control.void_type)
        {
            ReportSemError(SemanticError::MISPLACED_RETURN_WITH_EXPRESSION,
                           return_statement -> LeftToken(),
                           return_statement -> RightToken());
        }
        else if (return_statement -> expression_opt -> Type() != control.no_type)
        {
            if (this_method -> Type() != return_statement -> expression_opt -> Type())
            {
                if (CanAssignmentConvert(this_method -> Type(), return_statement -> expression_opt))
                    return_statement -> expression_opt = ConvertToType(return_statement -> expression_opt, this_method -> Type());
                else
                {
                    ReportSemError(SemanticError::MISMATCHED_RETURN_AND_METHOD_TYPE,
                                   return_statement -> expression_opt -> LeftToken(),
                                   return_statement -> expression_opt -> RightToken(),
                                   return_statement -> expression_opt -> Type() -> ContainingPackage() -> PackageName(),
                                   return_statement -> expression_opt -> Type() -> ExternalName(),
                                   this_method -> Type() -> ContainingPackage() -> PackageName(),
                                   this_method -> Type() -> ExternalName());
                }
            }
        }
    }
    else if (this_method -> Type() != control.void_type)
    {
        ReportSemError(SemanticError::MISPLACED_RETURN_WITH_NO_EXPRESSION,
                       return_statement -> LeftToken(),
                       return_statement -> RightToken());
    }

    return;
}


bool Semantic::CatchableException(TypeSymbol *exception)
{
    //
    // An unchecked exception or an error is ok !!
    //
    if (! CheckedException(exception) || exception == control.no_type)
        return true;

    //
    // Firstly, check the stack of try statements to see if the exception in question is catchable.
    //
    for (int i = TryStatementStack().Size() - 1; i >= 0; i--)
    {
        AstTryStatement *try_statement = (AstTryStatement *) TryStatementStack()[i];

        //
        // If a try statement contains a finally clause that can complete abruptly
        // then any exception that can reach it is assumed to be catchable.
        // See Spec 11.3.
        //
        if (try_statement -> finally_clause_opt && (! try_statement -> finally_clause_opt -> block -> can_complete_normally))
            return true;

        //
        // Check each catch clause in turn.
        //
        for (int k = 0; k < try_statement -> NumCatchClauses(); k++)
        {
            AstCatchClause *clause = try_statement -> CatchClause(k);
            VariableSymbol *symbol = clause -> parameter_symbol;
            if (CanAssignmentConvertReference(symbol -> Type(), exception))
                return true;
        }
    }

    //
    // If we are processing the initialization expression of a field,
    // ThisMethod() is not defined.
    //
    MethodSymbol *this_method = ThisMethod();
    if (this_method)
    {
        for (int l = this_method -> NumThrows() - 1; l >= 0; l--)
        {
            if (CanAssignmentConvertReference(this_method -> Throws(l), exception))
                return true;
        }

        if (this_method -> NumInitializerConstructors() > 0)
        {
            int j;
            for (j = this_method -> NumInitializerConstructors() - 1; j >= 0; j--)
            {
                MethodSymbol *method = this_method -> InitializerConstructor(j);
                int k;
                for (k = method -> NumThrows() - 1; k >= 0; k--)
                {
                    if (CanAssignmentConvertReference(method -> Throws(k), exception))
                        break;
                }
                if (k < 0) // no hit was found in method.
                    return false;
            }
            if (j < 0) // all the relevant constructors can catch the exception
                return true;
        }
    }

    return false;
}


void Semantic::ProcessThrowStatement(Ast *stmt)
{
    AstThrowStatement *throw_statement = (AstThrowStatement *) stmt;

    ProcessExpression(throw_statement -> expression);
    TypeSymbol *type = throw_statement -> expression -> Type();

    if (type != control.no_type && (! CanAssignmentConvertReference(control.Throwable(), type)))
    {
        ReportSemError(SemanticError::EXPRESSION_NOT_THROWABLE,
                       throw_statement -> LeftToken(),
                       throw_statement -> RightToken());
    }

    SymbolSet *exception_set = TryExceptionTableStack().Top();
    if (exception_set)
        exception_set -> AddElement(type);

    if (! CatchableException(type))
    {
        MethodSymbol *this_method = ThisMethod();
        MethodSymbol *method = (this_method && this_method -> Identity() != control.clinit_name_symbol
                                            && this_method -> Identity() != control.block_init_name_symbol
                                                            ? this_method
                                                            : (MethodSymbol *) NULL);

        if (TryStatementStack().Size() > 0)
            ReportSemError(SemanticError::BAD_THROWABLE_EXPRESSION_IN_TRY,
                           throw_statement -> LeftToken(),
                           throw_statement -> RightToken(),
                           type -> ContainingPackage() -> PackageName(),
                           type -> ExternalName(),
                           (method ? method -> Header() : StringConstant::US_EMPTY));
        else if (method)
             ReportSemError(SemanticError::BAD_THROWABLE_EXPRESSION_IN_METHOD,
                            throw_statement -> LeftToken(),
                            throw_statement -> RightToken(),
                            type -> ContainingPackage() -> PackageName(),
                            type -> ExternalName(),
                            method -> Header());
        else ReportSemError(SemanticError::BAD_THROWABLE_EXPRESSION,
                            throw_statement -> LeftToken(),
                            throw_statement -> RightToken(),
                            type -> ContainingPackage() -> PackageName(),
                            type -> ExternalName());
    }

    return;
}


void Semantic::ProcessTryStatement(Ast *stmt)
{
    AstTryStatement *try_statement = (AstTryStatement *) stmt;

    //
    // A try_statement containing a finally clause requires some extra local
    // variables in its immediately enclosing block. If it is enclosed in a method
    // that returns void then 2 extra elements are needed. If the method
    // returns a long or a double value, two additional elements are needed.
    // Otherwise, one additional element is needed.
    // If this try_statement is the first try_statement with a finally clause
    // that was encountered in the immediately enclosing block, we allocate
    // two extra slots for the special local variables.
    //
    AstBlock *enclosing_block = LocalBlockStack().TopBlock();
    if (try_statement -> finally_clause_opt)
    {
        BlockSymbol *enclosing_block_symbol = enclosing_block -> block_symbol;
        if (enclosing_block_symbol -> try_or_synchronized_variable_index == 0) // first such statement encountered in enclosing block?
        {
            enclosing_block_symbol -> try_or_synchronized_variable_index = enclosing_block_symbol -> max_variable_index;
            enclosing_block_symbol -> max_variable_index += 2;
            if (ThisMethod() -> Type() != control.void_type)
            {
                 if (control.IsDoubleWordType(ThisMethod() -> Type()))
                      enclosing_block_symbol -> max_variable_index += 2;
                 else enclosing_block_symbol -> max_variable_index += 1;
            }
        }

        //
        // A finally block is processed in the environment of its immediate enclosing block.
        // (as opposed to the environment of its associated try block).
        //
        // Note that the finally block must be processed prior to the other
        // blocks in the try statement, because the computation of whether or not
        // an exception is catchable in a try statement depends on the termination
        // status of the associated finally block. See CatchableException function.
        //
        AstBlock *block_body = try_statement -> finally_clause_opt -> block;
        block_body -> is_reachable = try_statement -> is_reachable;
        ProcessBlock(block_body);
    }

    //
    // Note that the catch clauses are processed first - prior to processing
    // the main block - so that we can have their parameters available when we
    // are processing the main block, in case that block contains a throw
    // statement. See ProcessThrowStatement for more information.
    //
    // Also, recall that the body of the catch blocks must not be
    // processed within the environment of the associated try whose
    // exceptions they are supposed to catch but within the immediate enclosing
    // block (which may itself be a try block).
    //
    for (int i = 0; i < try_statement -> NumCatchClauses(); i++)
    {
        AstCatchClause *clause = try_statement -> CatchClause(i);
        AstFormalParameter *parameter = clause -> formal_parameter;

        TypeSymbol *parm_type;

        if (parameter -> type -> PrimitiveTypeCast())
        {
            ReportSemError(SemanticError::CATCH_PRIMITIVE_TYPE,
                           parameter -> LeftToken(),
                           parameter -> RightToken());
            parm_type = control.Error();
        }
        else if (parameter -> type -> ArrayTypeCast())
        {
            ReportSemError(SemanticError::CATCH_ARRAY_TYPE,
                           parameter -> LeftToken(),
                           parameter -> RightToken());
            parm_type = control.Error();
        }
        else parm_type = MustFindType(parameter -> type);

        if (! parm_type -> IsSubclass(control.Throwable()))
        {
            ReportSemError(SemanticError::TYPE_NOT_THROWABLE,
                           parameter -> LeftToken(),
                           parameter -> RightToken(),
                           parm_type -> ContainingPackage() -> PackageName(),
                           parm_type -> ExternalName());
        }

        AstVariableDeclaratorId *name = parameter -> formal_declarator -> variable_declarator_name;
        NameSymbol *name_symbol = lex_stream -> NameSymbol(name -> identifier_token);
        if (LocalSymbolTable().FindVariableSymbol(name_symbol))
        {
            ReportSemError(SemanticError::DUPLICATE_LOCAL_VARIABLE_DECLARATION,
                           name -> identifier_token,
                           name -> identifier_token,
                           name_symbol -> Name());
        }

        AstBlock *block_body = clause -> block;
        //
        // Guess that the number of elements in the table will not exceed the number of statements + the clause parameter.
        //
        BlockSymbol *block = LocalSymbolTable().Top() -> InsertBlockSymbol(block_body -> NumStatements() + 1);
        block -> max_variable_index = enclosing_block -> block_symbol -> max_variable_index;
        LocalSymbolTable().Push(block -> Table());

        AccessFlags access_flags = ProcessFormalModifiers(parameter);

        VariableSymbol *symbol = LocalSymbolTable().Top() -> InsertVariableSymbol(name_symbol);
        symbol -> SetFlags(access_flags);
        symbol -> SetType(parm_type);
        symbol -> SetOwner(ThisMethod());
        symbol -> SetLocalVariableIndex(block -> max_variable_index++);
        symbol -> declarator = parameter -> formal_declarator;

        clause -> parameter_symbol = symbol;

        //
        // Note that for the purpose of semantic checking we assume that
        // the body of the catch block is reachable. Whether or not the catch
        // statement can be executed at all is checked later.
        //
        block_body -> is_reachable = true;

        block_body -> block_symbol = block;
        block_body -> nesting_level = LocalBlockStack().Size();
        LocalBlockStack().Push(block_body);

        ProcessBlockStatements(block_body);

        LocalBlockStack().Pop();
        LocalSymbolTable().Pop();

        //
        // Update the information for the block that immediately encloses the current block.
        //
        if (LocalBlockStack().TopMaxEnclosedVariableIndex() < block -> max_variable_index)
            LocalBlockStack().TopMaxEnclosedVariableIndex() = block -> max_variable_index;

        //
        // If a catch clause block can complete normally, we assume
        // that the try statement can complete normally. This may
        // prove to be false later if we find out that the finally
        // clause cannot complete normally...
        //
        if (block_body -> can_complete_normally)
            try_statement -> can_complete_normally = true;

        block -> CompressSpace(); // space optimization
    }

    //
    //
    //
    TryStatementStack().Push(try_statement);
    SymbolSet *exception_set = new SymbolSet;
    TryExceptionTableStack().Push(exception_set);

    try_statement -> block -> is_reachable = try_statement -> is_reachable;
    ProcessBlock(try_statement -> block);
    if (try_statement -> block -> can_complete_normally)
        try_statement -> can_complete_normally = true;

    //
    // A catch block is reachable iff both of the following are true:
    //
    //     . Some expression or throw statement in the try block is reachable
    //       and can throw an exception that is assignable to the parameter
    //       of the catch clause C.
    //
    //     . There is no earlier catch block A in the try statement such that the
    //       type of C's parameter is the same as or a subclass of the type of A's
    //       parameter.
    //
    // Note that the use of the word assignable here is slightly misleading.
    // It does not mean assignable in the strict sense defined in section 5.2.
    // Using the strict definition of 5.2, the rule can be more accurately
    // stated as follows:
    //
    //    . Catchable Exception:
    //      some expression or throw statement in the try block is reachable
    //      and can throw an exception S that is assignable to the parameter
    //      with type T (S is a subclass of T) of the catch clause C.
    //
    //      In this case, when S is thrown it will definitely be caught by
    //      clause C.
    //
    //    . Convertible Exception:
    //      the type T of the parameter of the catch clause C is assignable to
    //      the type S (T is a subclass of S) of an exception that can be thrown by
    //      some expression or throw statement in the try block that is reachable.
    //
    //      This rule captures the idea that at run time an object declared to
    //      be of type S can actually be an instance of an object of type T in
    //      which case it will be caught by clause C.
    //
    //
    Tuple<TypeSymbol *> catchable_exceptions,
                        convertible_exceptions;
    for (int l = 0; l < try_statement -> NumCatchClauses(); l++)
    {
        AstCatchClause *clause = try_statement -> CatchClause(l);
        VariableSymbol *symbol = clause -> parameter_symbol;
        if (CheckedException(symbol -> Type()))
        {
            int initial_length = catchable_exceptions.Length() + convertible_exceptions.Length();

            for (TypeSymbol *exception = (TypeSymbol *) exception_set -> FirstElement();
                 exception;
                 exception = (TypeSymbol *) exception_set -> NextElement())
            {
                if (CanAssignmentConvertReference(symbol -> Type(), exception))
                     catchable_exceptions.Next() = exception;
                else if (CanAssignmentConvertReference(exception, symbol -> Type()))
                     convertible_exceptions.Next() = exception;
            }

            //
            // No clause was found whose parameter can possibly accept this exception.
            //
            if ((catchable_exceptions.Length() + convertible_exceptions.Length()) == initial_length)
            {
                if (symbol -> Type() == control.Throwable() || symbol -> Type() == control.Exception())
                     ReportSemError(SemanticError::UNREACHABLE_DEFAULT_CATCH_CLAUSE,
                                    clause -> formal_parameter -> LeftToken(),
                                    clause -> formal_parameter -> RightToken(),
                                    symbol -> Type() -> ContainingPackage() -> PackageName(),
                                    symbol -> Type() -> ExternalName());
                else ReportSemError(SemanticError::UNREACHABLE_CATCH_CLAUSE,
                                    clause -> formal_parameter -> LeftToken(),
                                    clause -> formal_parameter -> RightToken(),
                                    symbol -> Type() -> ContainingPackage() -> PackageName(),
                                    symbol -> Type() -> ExternalName());
            }
            else
            {
                //
                // TODO: I know, I know, this is a sequential search...
                //
                AstCatchClause *previous_clause;
                int k;
                for (k = 0; k < l; k++)
                {
                    previous_clause = try_statement -> CatchClause(k);
                    if (symbol -> Type() -> IsSubclass(previous_clause -> parameter_symbol -> Type()))
                        break;
                }

                if (k < l)
                {
                     FileLocation loc(lex_stream, previous_clause -> formal_parameter -> RightToken());
                     ReportSemError(SemanticError::BLOCKED_CATCH_CLAUSE,
                                    clause -> formal_parameter -> LeftToken(),
                                    clause -> formal_parameter -> RightToken(),
                                    symbol -> Type() -> ContainingPackage() -> PackageName(),
                                    symbol -> Type() -> ExternalName(),
                                    loc.location);
                }
                else clause -> block -> is_reachable = true;
            }
        }
    }

    TryStatementStack().Pop();
    TryExceptionTableStack().Pop();
    if (TryExceptionTableStack().Top())
    {
        //
        // First, remove all the thrown exceptions that are definitely caught by the
        // enclosing try statement. Then, add the remaining ones to the set that must
        // be caught by the immediately enclosing try statement.
        //
        for (int i = 0; i < catchable_exceptions.Length(); i++)
            exception_set -> RemoveElement(catchable_exceptions[i]);
        TryExceptionTableStack().Top() -> Union(*exception_set);
    }
    delete exception_set;

    //
    // A try statement cannot complete normally if it contains a finally
    // clause that cannot complete normally.
    //
    if (try_statement -> finally_clause_opt && (! try_statement -> finally_clause_opt -> block -> can_complete_normally))
        try_statement -> can_complete_normally = false;

    return;
}


void Semantic::ProcessEmptyStatement(Ast *stmt)
{
    AstEmptyStatement *empty_statement = (AstEmptyStatement *) stmt;

    //
    // An empty statement can complete normally iff it is reachable.
    //
    empty_statement -> can_complete_normally = empty_statement -> is_reachable;

    return;
}


TypeSymbol *Semantic::GetLocalType(AstClassDeclaration *class_declaration)
{
    NameSymbol *name_symbol = lex_stream -> NameSymbol(class_declaration -> identifier_token);
    TypeSymbol *type = LocalSymbolTable().Top() -> InsertNestedTypeSymbol(name_symbol);

    TypeSymbol *outermost_type = ThisType() -> outermost_type;
    if (! outermost_type -> local)
        outermost_type -> local = new SymbolSet;

    IntToWstring value(outermost_type -> local -> NameCount(name_symbol) + 1);

    int length = value.Length() + outermost_type -> NameLength() + 1 + name_symbol -> NameLength() + 1; // +1 for $,... +1 for $
    wchar_t *external_name = new wchar_t[length + 1]; // +1 for '\0';
    wcscpy(external_name, outermost_type -> Name());
    wcscat(external_name, StringConstant::US__DS);
    wcscat(external_name, value.String());
    wcscat(external_name, StringConstant::US__DS);
    wcscat(external_name, name_symbol -> Name());

    type -> SetACC_PRIVATE();
    type -> outermost_type = outermost_type;
    type -> SetExternalIdentity(control.FindOrInsertName(external_name, length));
    outermost_type -> local -> AddElement(type);

    delete [] external_name;

    return type;
}


void Semantic::ProcessClassDeclaration(Ast *stmt)
{
    AstClassDeclaration *class_declaration = (AstClassDeclaration *) stmt;
    AstClassBody *class_body = class_declaration -> class_body;

    class_declaration -> MarkLocal(); // identify class as "statement" and assert that it is "reachable" and "can_complete_normally"
    CheckNestedTypeDuplication(state_stack.Top(), class_declaration -> identifier_token);

    TypeSymbol *inner_type = GetLocalType(class_declaration);
    inner_type -> outermost_type = ThisType() -> outermost_type;
    inner_type -> supertypes_closure = new SymbolSet;
    inner_type -> subtypes_closure = new SymbolSet;
    inner_type -> subtypes = new SymbolSet;
    inner_type -> semantic_environment = new SemanticEnvironment((Semantic *) this,
                                                                 inner_type,
                                                                 state_stack.Top());
    inner_type -> declaration = class_declaration;
    inner_type -> file_symbol = source_file_symbol;
    inner_type -> SetFlags(ProcessLocalClassModifiers(class_declaration));
    inner_type -> SetOwner(ThisMethod());
    //
    // Add 3 extra elements for padding. May need a default constructor and other support elements.
    //
    inner_type -> SetSymbolTable(class_body -> NumClassBodyDeclarations() + 3);
    inner_type -> SetLocation();
    inner_type -> SetSignature(control);

    if (StaticRegion())
         inner_type -> SetACC_STATIC();
    else inner_type -> InsertThis(0);

    class_declaration -> semantic_environment = inner_type -> semantic_environment; // save for processing bodies later.

    CheckClassMembers(inner_type, class_body);

    ProcessTypeHeaders(class_declaration);

    ProcessMembers(class_declaration -> semantic_environment, class_body);
    CompleteSymbolTable(class_declaration -> semantic_environment, class_declaration -> identifier_token, class_body);
    ProcessExecutableBodies(class_declaration -> semantic_environment, class_body);

    UpdateLocalConstructors(inner_type);

    return;
}


void Semantic::ProcessThisCall(AstThisCall *this_call)
{
    TypeSymbol *this_type = ThisType(),
               *containing_type = this_type -> ContainingType();

    ExplicitConstructorInvocation() = this_call; // signal that we are about to process an explicit constructor invocation

    if (this_call -> base_opt)
    {
        ProcessExpression(this_call -> base_opt);

        TypeSymbol *expr_type = this_call -> base_opt -> Type();
        if (expr_type != control.no_type)
        {
            if (! containing_type)
            {
                ReportSemError(SemanticError::TYPE_NOT_INNER_CLASS,
                               this_call -> base_opt -> LeftToken(),
                               this_call -> base_opt -> RightToken(),
                               this_type -> ContainingPackage() -> PackageName(),
                               this_type -> ExternalName(),
                               expr_type -> ContainingPackage() -> PackageName(),
                               expr_type -> ExternalName());
                this_call -> base_opt -> symbol = control.no_type;
            }
            //
            // 1.2 change. In 1.1, we used to allow access to any subclass of type. Now, there must
            // be a perfect match.
            //
            // else if (! expr_type -> IsSubclass(containing_type))
            //
            else if (expr_type != containing_type)
            {
                ReportSemError(SemanticError::INVALID_ENCLOSING_INSTANCE,
                               this_call -> base_opt -> LeftToken(),
                               this_call -> base_opt -> RightToken(),
                               this_type -> ContainingPackage() -> PackageName(),
                               this_type -> ExternalName(),
                               containing_type -> ContainingPackage() -> PackageName(),
                               containing_type -> ExternalName(),
                               expr_type -> ContainingPackage() -> PackageName(),
                               expr_type -> ExternalName());
                this_call -> base_opt -> symbol = control.no_type;
            }
        }
    }
    else // (! this_call -> base_opt)
    {
        if (this_type -> IsInner())
            this_call -> base_opt = CreateAccessToType(this_call, containing_type);
    }

    bool no_bad_argument = true;

    for (int i = 0; i < this_call -> NumArguments(); i++)
    {
        AstExpression *expr = (AstExpression *) this_call -> Argument(i);
        ProcessExpressionOrStringConstant(expr);
        no_bad_argument = no_bad_argument && (expr -> Type() != control.no_type);
    }
    if (no_bad_argument)
    {
        MethodSymbol *constructor = FindConstructor(this_type, this_call, this_call -> this_token, this_call -> RightToken());
        if (constructor)
        {
            this_call -> symbol = constructor;

            for (int i = 0; i < this_call -> NumArguments(); i++)
            {
                AstExpression *expr = this_call -> Argument(i);
                if (expr -> Type() != constructor -> FormalParameter(i) -> Type())
                    this_call -> Argument(i) = ConvertToType(expr, constructor -> FormalParameter(i) -> Type());
            }

            for (int k = constructor -> NumThrows() - 1; k >= 0; k--)
            {
                TypeSymbol *exception = constructor -> Throws(k);
                if (! CatchableException(exception))
                {
                    ReportSemError(SemanticError::CONSTRUCTOR_DOES_NOT_THROW_THIS_EXCEPTION,
                                   this_call -> this_token,
                                   this_call -> this_token,
                                   exception -> ContainingPackage() -> PackageName(),
                                   exception -> ExternalName());
                }
            }

            if (this_type -> IsLocal()) // a local type may use enclosed local variables?
                this_type -> AddLocalConstructorCallEnvironment(GetEnvironment(this_call));

            //
            // Note that there is no need to do access-checking as we are allowed,
            // within the body of a class, to invoke any other constructor or member
            // (private or otherwise) in that class.
            //
        }
    }

    ExplicitConstructorInvocation() = NULL; // signal that we are no longer processing an explicit constructor invocation

    this_call -> can_complete_normally = this_call -> is_reachable;

    return;
}


void Semantic::ProcessSuperCall(AstSuperCall *super_call)
{
    TypeSymbol *this_type = ThisType();
    ExplicitConstructorInvocation() = super_call; // signal that we are about to process an explicit constructor invocation

    TypeSymbol *super_type = this_type -> super;
    if (! super_type) // this is only possible if we are compiling an illegal Object.java source file.
        super_type = control.Object();

    if (super_call -> base_opt)
    {
        ProcessExpression(super_call -> base_opt);

        TypeSymbol *expr_type = super_call -> base_opt -> Type();
        if (expr_type != control.no_type)
        {
            TypeSymbol *containing_type = super_type -> ContainingType();
            if (! containing_type)
            {
                ReportSemError(SemanticError::SUPER_TYPE_NOT_INNER_CLASS,
                               super_call -> base_opt -> LeftToken(),
                               super_call -> base_opt -> RightToken(),
                               super_type -> ContainingPackage() -> PackageName(),
                               super_type -> ExternalName(),
                               this_type -> ContainingPackage() -> PackageName(),
                               this_type -> ExternalName(),
                               expr_type -> ContainingPackage() -> PackageName(),
                               expr_type -> ExternalName());
                super_call -> base_opt -> symbol = control.no_type;
            }
            //
            // 1.2 change. In 1.1, we used to allow access to any subclass of type. Now, there must
            // be a perfect match.
            //
            // else if (! expr_type -> IsSubclass(containing_type))
            //
            else if (expr_type != containing_type)
            {
                ReportSemError(SemanticError::INVALID_ENCLOSING_INSTANCE,
                               super_call -> base_opt -> LeftToken(),
                               super_call -> base_opt -> RightToken(),
                               this_type -> ContainingPackage() -> PackageName(),
                               this_type -> ExternalName(),
                               containing_type -> ContainingPackage() -> PackageName(),
                               containing_type -> ExternalName(),
                               expr_type -> ContainingPackage() -> PackageName(),
                               expr_type -> ExternalName());
                super_call -> base_opt -> symbol = control.no_type;
            }
        }
    }
    else // (! super_call -> base_opt)
    {
        if (super_type && super_type -> IsInner())
            super_call -> base_opt = CreateAccessToType(super_call, super_type -> ContainingType());
    }

    bool no_bad_argument = true;
    for (int i = 0; i < super_call -> NumArguments(); i++)
    {
        AstExpression *expr = (AstExpression *) super_call -> Argument(i);
        ProcessExpressionOrStringConstant(expr);
        no_bad_argument = no_bad_argument && (expr -> Type() != control.no_type);
    }

    if (this_type == control.Object())
    {
        super_call -> symbol = NULL;
        ReportSemError(SemanticError::MISPLACED_SUPER_EXPRESSION,
                       super_call -> super_token,
                       super_call -> super_token);
    }
    else if (no_bad_argument)
    {
        MethodSymbol *constructor = FindConstructor(super_type, super_call, super_call -> super_token, super_call -> RightToken());

        if (constructor)
        {
            //
            // No need to do a full access-check. Do the minimal stuff here !
            //
            if (constructor -> ACC_PRIVATE())
            {
                if (this_type -> outermost_type == super_type -> outermost_type)
                {
                     if (! constructor -> LocalConstructor())
                     {
                         constructor = super_type -> GetReadAccessMethod(constructor);

                         //
                         // Add extra argument for read access constructor;
                         //
                         super_call -> AddNullArgument();
                     }
                }
                else ReportSemError(SemanticError::PRIVATE_CONSTRUCTOR_NOT_ACCESSIBLE,
                                    super_call -> LeftToken(),
                                    super_call -> RightToken(),
                                    constructor -> Header(),
                                    super_type -> ContainingPackage() -> PackageName(),
                                    super_type -> ExternalName());
            }
            else if (! (constructor -> ACC_PUBLIC() || constructor -> ACC_PROTECTED()))
            {
                if (! (this_type -> outermost_type == super_type -> outermost_type ||
                       super_type -> ContainingPackage() == this_package))
                    ReportSemError(SemanticError::DEFAULT_CONSTRUCTOR_NOT_ACCESSIBLE,
                                   super_call -> super_token,
                                   super_call -> super_token,
                                   constructor -> Header(),
                                   super_type -> ContainingPackage() -> PackageName(),
                                   super_type -> ExternalName());
            }

            super_call -> symbol = constructor;

            if (super_call -> base_opt &&
                (super_call -> base_opt -> Type() != control.no_type) &&
                (super_call -> base_opt -> Type() != super_type -> ContainingType()))
            {
                assert(CanMethodInvocationConvert(super_type -> ContainingType(), super_call -> base_opt -> Type()));

                super_call -> base_opt = ConvertToType(super_call -> base_opt, super_type -> ContainingType());
            }

            for (int i = 0; i < super_call -> NumArguments(); i++)
            {
                AstExpression *expr = super_call -> Argument(i);
                TypeSymbol * ctor_param_type;
                if (super_call -> NeedsExtraNullArgument()) {
                    // Synthetic constructor signature includes a synthetic
                    // class pointer as the first parameter.
                    ctor_param_type = constructor -> FormalParameter(i + 1) -> Type();
                } else {
                    ctor_param_type = constructor -> FormalParameter(i) -> Type();
                }
                if (expr -> Type() != ctor_param_type)
                    super_call -> Argument(i) = ConvertToType(expr, ctor_param_type);
            }

            //
            // Make sure that the throws signature of the constructor is processed.
            //
            for (int k = constructor -> NumThrows() - 1; k >= 0; k--)
            {
                TypeSymbol *exception = constructor -> Throws(k);
                if (! CatchableException(exception))
                {
                    ReportSemError(SemanticError::CONSTRUCTOR_DOES_NOT_THROW_SUPER_EXCEPTION,
                                   super_call -> LeftToken(),
                                   super_call -> RightToken(),
                                   this_type -> Name(),
                                   exception -> ContainingPackage() -> PackageName(),
                                   exception -> ExternalName(),
                                   constructor -> containing_type -> ContainingPackage() -> PackageName(),
                                   constructor -> containing_type -> ExternalName());
                }
            }

            if (super_type -> IsLocal()) // a local type may use enclosed local variables?
            {
                if (super_type -> LocalClassProcessingCompleted())
                {
                    assert(ThisMethod() -> LocalConstructor() && (! ThisMethod() -> IsGeneratedLocalConstructor()));

                    assert(constructor -> LocalConstructor() && (! constructor -> IsGeneratedLocalConstructor()));

                    super_call -> symbol = constructor -> LocalConstructor();

                    //
                    // Recall that as a side-effect, when a local shadow is created in a type
                    // an argument that will be used to initialize the local shadow that has
                    // the same identity must be passed to every constructor in the type. Since
                    // we are currently processing a constructor, such an argument must be available.
                    //
                    BlockSymbol *block_symbol = ThisMethod() -> LocalConstructor() -> block_symbol;
                    for (int i = (super_type -> ACC_STATIC() ? 0 : 1); i < super_type -> NumConstructorParameters(); i++)
                    {
                        VariableSymbol *local = super_type -> ConstructorParameter(i) -> accessed_local,
                                       *local_shadow = this_type -> FindOrInsertLocalShadow(local);

                        AstSimpleName *simple_name = compilation_unit -> ast_pool -> GenSimpleName(super_call -> super_token);
                        simple_name -> symbol = block_symbol -> FindVariableSymbol(local_shadow -> Identity());

                        assert(simple_name -> symbol);

                        super_call -> AddLocalArgument(simple_name);
                    }
                }
                else // are we currently within the body of the type in question ?
                {
                    super_type -> AddLocalConstructorCallEnvironment(GetEnvironment(super_call));
                }
            }
        }
    }

    ExplicitConstructorInvocation() = NULL; // signal that we are no longer processing an explicit constructor invocation

    super_call -> can_complete_normally = super_call -> is_reachable;

    return;
}


void Semantic::CheckThrow(AstExpression *throw_expression)
{
    TypeSymbol *throw_type = throw_expression -> symbol -> TypeCast();

    assert(throw_type);

    if (throw_type -> ACC_INTERFACE())
    {
        ReportSemError(SemanticError::NOT_A_CLASS,
                       throw_expression -> LeftToken(),
                       throw_expression -> RightToken(),
                       throw_type -> ContainingPackage() -> PackageName(),
                       throw_type -> ExternalName());
    }
    else if (! throw_type -> IsSubclass(control.Throwable()))
    {
        ReportSemError(SemanticError::TYPE_NOT_THROWABLE,
                       throw_expression -> LeftToken(),
                       throw_expression -> RightToken(),
                       throw_type -> ContainingPackage() -> PackageName(),
                       throw_type -> ExternalName());
    }

    return;
}


void Semantic::ProcessMethodBody(AstMethodDeclaration *method_declaration)
{
    MethodSymbol *this_method = ThisMethod();

    for (int k = 0; k < method_declaration -> NumThrows(); k++)
        CheckThrow(method_declaration -> Throw(k));


    if (! method_declaration -> method_body -> EmptyStatementCast())
    {
        //
        // The block that is the body of a method is reachable
        //
        AstBlock *block_body;

        //
        // The body of a method must be a regular block. If instead, it
        // is a constructor block, mark the compilation unit as a bad
        // compilation so that the parser can properly diagnose this
        // problem later.
        //
        AstConstructorBlock *constructor_block = method_declaration -> method_body -> ConstructorBlockCast();
        if (constructor_block)
        {
            compilation_unit -> kind = Ast::BAD_COMPILATION; // invalidate the compilation unit

            constructor_block -> is_reachable = true;
            block_body = constructor_block -> block;

            //
            // If the parser recognizes the body of a method as a ConstructorBlock
            // then it must have an explicit_constructor_invocation.
            //
            AstThisCall *this_call = constructor_block -> explicit_constructor_invocation_opt -> ThisCallCast();
            if (this_call)
            {
                this_call -> is_reachable = true;
                //
                // Do not process the explicit constructor invocation as this could
                // cause problems with assertions (e.g. for inner classes) that will
                // turn out not to be true.
                //
                // ProcessThisCall(this_call);
                //
                block_body -> is_reachable = this_call -> can_complete_normally;
            }
            else
            {
                AstSuperCall *super_call = (AstSuperCall *) constructor_block -> explicit_constructor_invocation_opt;
                super_call -> is_reachable = true;
                //
                // Do not process the explicit constructor invocation as this could
                // cause problems with assertions (e.g. for inner classes) that will
                // turn out not to be true.
                //
                // ProcessSuperCall(super_call);
                //
                block_body -> is_reachable = super_call -> can_complete_normally;
            }
        }
        else
        {
            block_body = (AstBlock *) method_declaration -> method_body;
            block_body -> is_reachable = true;
        }

        block_body -> block_symbol = this_method -> block_symbol;
        block_body -> nesting_level = LocalBlockStack().Size();
        LocalBlockStack().Push(block_body);

        ProcessBlockStatements(block_body);

        LocalBlockStack().Pop();

        if (block_body -> can_complete_normally)
        {
            if (this_method -> Type() == control.void_type)
            {
                AstReturnStatement *return_statement = compilation_unit -> ast_pool -> GenReturnStatement();
                return_statement -> return_token = block_body -> right_brace_token;
                return_statement -> expression_opt = NULL;
                return_statement -> semicolon_token = block_body -> right_brace_token;
                return_statement -> is_reachable = true;
                block_body -> can_complete_normally = false;
                block_body -> AddStatement(return_statement);
            }
            else
            {
                ReportSemError(SemanticError::TYPED_METHOD_WITH_NO_RETURN,
                               method_declaration -> type -> LeftToken(),
                               method_declaration -> method_declarator -> identifier_token,
                               this_method -> Header(),
                               this_method -> Type() -> Name());
            }
        }

        if (this_method -> ACC_ABSTRACT() || this_method -> ACC_NATIVE())
        {
            ReportSemError(SemanticError::ABSTRACT_METHOD_WITH_BODY,
                           method_declaration -> LeftToken(),
                           method_declaration -> RightToken(),
                           this_method -> Header());
        }
    }
    else if (! (this_method -> ACC_ABSTRACT() || this_method -> ACC_NATIVE()))
    {
        ReportSemError(SemanticError::NON_ABSTRACT_METHOD_WITHOUT_BODY,
                       method_declaration -> LeftToken(),
                       method_declaration -> RightToken(),
                       this_method -> Header());
    }

    this_method -> block_symbol -> CompressSpace(); // space optimization

    return;
}


void Semantic::ProcessConstructorBody(AstConstructorDeclaration *constructor_declaration, bool body_reachable)
{
    TypeSymbol *this_type = ThisType();
    MethodSymbol *this_method = ThisMethod();

    for (int k = 0; k < constructor_declaration -> NumThrows(); k++)
        CheckThrow(constructor_declaration -> Throw(k));

    //
    // The block that is the body of a constructor is reachable
    //
    AstConstructorBlock *constructor_block = constructor_declaration -> constructor_body;

    constructor_block -> is_reachable = true;
    AstBlock *block_body = constructor_block -> block;
    AstThisCall *this_call = NULL;
    AstSuperCall *super_call = NULL;
    TypeSymbol *super_type = this_type -> super;

    if (constructor_block -> explicit_constructor_invocation_opt)
    {
        this_call = constructor_block -> explicit_constructor_invocation_opt -> ThisCallCast();
        super_call = constructor_block -> explicit_constructor_invocation_opt -> SuperCallCast();
    }
    else if (super_type)
    {
        LexStream::TokenIndex loc = block_body -> LeftToken();
        super_call                            = compilation_unit -> ast_pool -> GenSuperCall();
        super_call -> base_opt                = NULL;
        super_call -> dot_token_opt           = loc;
        super_call -> super_token             = loc;
        super_call -> left_parenthesis_token  = loc;
        super_call -> right_parenthesis_token = loc;
        super_call -> semicolon_token         = loc;

        constructor_block -> explicit_constructor_invocation_opt = super_call;

        if (super_type -> IsInner() && (! this_type -> CanAccess(super_type -> ContainingType())))
        {
            ReportSemError(SemanticError::ENCLOSING_INSTANCE_NOT_ACCESSIBLE,
                           constructor_declaration -> constructor_declarator -> LeftToken(),
                           constructor_declaration -> constructor_declarator -> RightToken(),
                           super_type -> ContainingType() -> ContainingPackage() -> PackageName(),
                           super_type -> ContainingType() -> ExternalName());
        }
    }

    //
    // If the constructor starts with an explicit_constructor_invocation, either
    // one specified by the user or generated, we process it and set up the proper
    // local environment, if appropriate...
    //
    if (constructor_block -> explicit_constructor_invocation_opt)
    {
        //
        // If we are processing a local constructor, set up the generated environment...
        //
        if (this_type -> IsLocal())
        {
            LocalSymbolTable().Pop();

            assert(this_method -> LocalConstructor() && (! this_method -> IsGeneratedLocalConstructor()));

            LocalSymbolTable().Push(this_method -> LocalConstructor() -> block_symbol -> Table());
        }

            if (this_call)
            {
                this_call -> is_reachable = true;
                ProcessThisCall(this_call);
            }
            else
            {
                assert(super_call);

                super_call -> is_reachable = true;
                ProcessSuperCall(super_call);
            }

        //
        // If we are processing a local constructor, restore its original environment...
        //
        if (this_type -> IsLocal())
        {
            LocalSymbolTable().Pop();
            LocalSymbolTable().Push(this_method -> block_symbol -> Table());
        }
    }

    if (! (body_reachable || (constructor_block -> explicit_constructor_invocation_opt &&
                              constructor_block -> explicit_constructor_invocation_opt -> ThisCallCast())))
    {
        ReportSemError(SemanticError::UNREACHABLE_CONSTRUCTOR_BODY,
                       constructor_declaration -> LeftToken(),
                       constructor_declaration -> RightToken());
    }

    //
    // Guess that the number of elements will not exceed the number of statements.
    //
    int table_size = block_body -> NumStatements();
    BlockSymbol *block = LocalSymbolTable().Top() -> InsertBlockSymbol(table_size);
    block -> max_variable_index = this_method -> block_symbol -> max_variable_index;
    LocalSymbolTable().Push(block -> Table());

    block_body -> is_reachable = true;
    block_body -> block_symbol = block;
    block_body -> nesting_level = LocalBlockStack().Size();
    LocalBlockStack().Push(block_body);

    ProcessBlockStatements(block_body);

    if (block_body -> can_complete_normally)
    {
        AstReturnStatement *return_statement = compilation_unit -> ast_pool -> GenReturnStatement();
        return_statement -> return_token = block_body -> right_brace_token;
        return_statement -> expression_opt = NULL;
        return_statement -> semicolon_token = block_body -> right_brace_token;
        return_statement -> is_reachable = true;
        block_body -> can_complete_normally = false;
        block_body -> AddStatement(return_statement);
    }

    constructor_block -> can_complete_normally = block_body -> can_complete_normally;

    LocalBlockStack().Pop();
    LocalSymbolTable().Pop();

    //
    // Update the local variable info for the main block associated with this constructor.
    //
    if (this_method -> block_symbol -> max_variable_index < block -> max_variable_index)
        this_method -> block_symbol -> max_variable_index = block -> max_variable_index;

    block -> CompressSpace(); // space optimization

    return;
}


void Semantic::ProcessExecutableBodies(SemanticEnvironment *environment, AstClassBody *class_body)
{
    state_stack.Push(environment);
    TypeSymbol *this_type = ThisType();

    assert(this_type -> HeaderProcessed());
    assert(this_type -> ConstructorMembersProcessed());
    assert(this_type -> MethodMembersProcessed());
    assert(this_type -> FieldMembersProcessed());

    ThisVariable() = NULL; // All variable declarations have already been processed

    //
    // Compute the set of instance final variables declared by the user in this type
    // as well as the set of instance final variables that have not yet been initialized.
    //
    Tuple<VariableSymbol *> finals(this_type -> NumVariableSymbols()),
                            unassigned_finals(this_type -> NumVariableSymbols());
    for (int k = 0; k < this_type -> NumVariableSymbols(); k++)
    {
        VariableSymbol *variable_symbol = this_type -> VariableSym(k);
        if (variable_symbol -> ACC_FINAL() && variable_symbol -> declarator)
        {
            finals.Next() = variable_symbol;

            if (! variable_symbol -> IsDefinitelyAssigned())
                unassigned_finals.Next() = variable_symbol;
        }
    }

    AstBlock *last_block_body = (class_body -> NumBlocks() > 0 ? class_body -> Block(class_body -> NumBlocks() - 1)
                                                               : (AstBlock *) NULL);
    if (class_body -> NumConstructors() == 0)
    {
        //
        // Issue an error for each unassigned final.
        //
        for (int k = 0; k < unassigned_finals.Length(); k++)
        {
            ReportSemError(SemanticError::UNINITIALIZED_FINAL_VARIABLE,
                           unassigned_finals[k] -> declarator -> LeftToken(),
                           unassigned_finals[k] -> declarator -> RightToken());
        }

        //
        // Process the body of the default constructor, if there is one.
        // (An anonymous class does not yet have a default constructor at this point.)
        //
        AstConstructorDeclaration *constructor_decl = class_body -> default_constructor;
        if (constructor_decl)
        {
            ThisMethod() = constructor_decl -> constructor_symbol;

            LocalSymbolTable().Push(ThisMethod() -> block_symbol -> Table());
            LocalBlockStack().max_size = 0;
            ProcessConstructorBody(constructor_decl, ((! last_block_body) || last_block_body -> can_complete_normally));
            LocalSymbolTable().Pop();
            ThisMethod() -> max_block_depth = LocalBlockStack().max_size;
        }
    }
    else
    {
        for (int i = 0; i < class_body -> NumConstructors(); i++)
        {
            AstConstructorDeclaration *constructor_decl = class_body -> Constructor(i);

            ThisMethod() = constructor_decl -> constructor_symbol;
            MethodSymbol *this_method = ThisMethod();
            if (this_method)
            {
                for (int l = 0; l < this_method -> NumFormalParameters(); l++)
                {
                    VariableSymbol *parm = this_method -> FormalParameter(l);
                    AstVariableDeclaratorId *name = parm -> declarator -> variable_declarator_name;

                    SemanticEnvironment *where_found;
                    Tuple<VariableSymbol *> variables_found(2);
                    SearchForVariableInEnvironment(variables_found, where_found, state_stack.Top(),
                                                   parm -> Identity(),
                                                   name -> identifier_token);
                    VariableSymbol *symbol = (variables_found.Length() > 0 ? variables_found[0] : (VariableSymbol *) NULL);
                    if (symbol && symbol -> IsLocal())
                    {
                        ReportSemError(SemanticError::DUPLICATE_LOCAL_VARIABLE_DECLARATION,
                                       name -> identifier_token,
                                       name -> identifier_token,
                                       parm -> Name());
                    }
                }

                AstConstructorBlock *constructor_block = constructor_decl -> constructor_body;
                if (constructor_block -> explicit_constructor_invocation_opt &&
                    constructor_block -> explicit_constructor_invocation_opt -> ThisCallCast())
                {
                    for (int j = 0; j < unassigned_finals.Length(); j++)
                        unassigned_finals[j] -> MarkDefinitelyAssigned();
                }
                else
                {
                    for (int j = 0; j < unassigned_finals.Length(); j++)
                        unassigned_finals[j] -> MarkNotDefinitelyAssigned();
                }

                LocalSymbolTable().Push(this_method -> block_symbol -> Table());
                LocalBlockStack().max_size = 0;

                int start_num_errors = NumErrors();
                ProcessConstructorBody(constructor_decl, ((! last_block_body) || last_block_body -> can_complete_normally));

                LocalSymbolTable().Pop();
                this_method -> max_block_depth = LocalBlockStack().max_size;

                if (NumErrors() == start_num_errors)
                    DefiniteConstructorBody(constructor_decl, finals);

                for (int k = 0; k < unassigned_finals.Length(); k++)
                {
                    VariableSymbol *variable_symbol = unassigned_finals[k];
                    if (! variable_symbol -> IsDefinitelyAssigned())
                    {
                        ReportSemError(SemanticError::UNINITIALIZED_FINAL_VARIABLE_IN_CONSTRUCTOR,
                                       constructor_decl -> LeftToken(),
                                       constructor_decl -> RightToken(),
                                       variable_symbol -> Name());
                    }
                }
            }
        }

        for (int l = 0; l < this_type -> NumPrivateAccessConstructors(); l++)
        {
            ThisMethod() = this_type -> PrivateAccessConstructor(l);
            MethodSymbol *this_method = ThisMethod();
            AstConstructorDeclaration *constructor_decl = (AstConstructorDeclaration *)
                                                          this_method -> method_or_constructor_declaration;

            LocalSymbolTable().Push(this_method -> block_symbol -> Table());
            LocalBlockStack().max_size = 0;
            ProcessConstructorBody(constructor_decl, true);
            LocalSymbolTable().Pop();
            this_method -> max_block_depth = LocalBlockStack().max_size;
        }

        ConstructorCycleChecker cycle_checker(class_body);
    }

    for (int j = 0; j < class_body -> NumMethods(); j++)
    {
        AstMethodDeclaration *method_decl = class_body -> Method(j);

        ThisMethod() = method_decl -> method_symbol;
        MethodSymbol *this_method = ThisMethod();
        if (this_method)
        {
            //
            // TODO: Confirm that this new test is indeed necessary. In 1.0, a more restricted test was used...
            //
            for (int i = 0; i < this_method -> NumFormalParameters(); i++)
            {
                VariableSymbol *parm = this_method -> FormalParameter(i);
                AstVariableDeclaratorId *name = parm -> declarator -> variable_declarator_name;

                SemanticEnvironment *where_found;
                Tuple<VariableSymbol *> variables_found(2);
                SearchForVariableInEnvironment(variables_found, where_found, state_stack.Top(),
                                               parm -> Identity(),
                                               name -> identifier_token);
                VariableSymbol *symbol = (variables_found.Length() > 0 ? variables_found[0] : (VariableSymbol *) NULL);
                if (symbol && symbol -> IsLocal())
                {
                    ReportSemError(SemanticError::DUPLICATE_LOCAL_VARIABLE_DECLARATION,
                                   name -> identifier_token,
                                   name -> identifier_token,
                                   parm -> Name());
                }
            }

            LocalSymbolTable().Push(this_method -> block_symbol -> Table());
            LocalBlockStack().max_size = 0;

            int start_num_errors = NumErrors();
            ProcessMethodBody(method_decl);

            LocalSymbolTable().Pop();
            this_method -> max_block_depth = LocalBlockStack().max_size;

            if (NumErrors() == start_num_errors)
                DefiniteMethodBody(method_decl, finals);
        }
    }

    //
    // Mark all instance variables and constructor parameters final.
    //
    for (int i = 0; i <  this_type -> NumConstructorParameters(); i++)
        this_type -> ConstructorParameter(i) -> SetACC_FINAL();

    for (int l = 0; l <  this_type -> NumEnclosingInstances(); l++)
        this_type -> EnclosingInstance(l) -> SetACC_FINAL();

    //
    // We are done with all the methods, indicate that there is no method
    // being currently compiled in this environment.
    //
    ThisMethod() = NULL;

    //
    // Recursively process all inner types
    //
    for (int m = 0; m < class_body -> NumNestedClasses(); m++)
    {
        AstClassDeclaration *class_declaration = class_body -> NestedClass(m);
        if (class_declaration -> semantic_environment)
            ProcessExecutableBodies(class_declaration -> semantic_environment, class_declaration -> class_body);
    }

    for (int n = 0; n < class_body -> NumNestedInterfaces(); n++)
    {
        if (class_body -> NestedInterface(n) -> semantic_environment)
            ProcessExecutableBodies(class_body -> NestedInterface(n));
    }

    state_stack.Pop();

    return;
}


void Semantic::ProcessExecutableBodies(AstInterfaceDeclaration *interface_declaration)
{
    state_stack.Push(interface_declaration -> semantic_environment);
    TypeSymbol *this_type = ThisType();

    assert(this_type -> HeaderProcessed());
    assert(this_type -> MethodMembersProcessed());
    assert(this_type -> FieldMembersProcessed());

    for (int k = 0; k < this_type -> NumVariableSymbols(); k++)
    {
        VariableSymbol *variable_symbol = this_type -> VariableSym(k);
        if (! variable_symbol -> IsDefinitelyAssigned())
        {
            ReportSemError(SemanticError::UNINITIALIZED_FINAL_VARIABLE,
                           variable_symbol -> declarator -> LeftToken(),
                           variable_symbol -> declarator -> RightToken());
        }
    }

    //
    // Recursively process all inner types
    //
    for (int m = 0; m < interface_declaration -> NumNestedClasses(); m++)
    {
        AstClassDeclaration *class_declaration = interface_declaration -> NestedClass(m);
        if (class_declaration -> semantic_environment)
            ProcessExecutableBodies(class_declaration -> semantic_environment, class_declaration -> class_body);
    }

    for (int n = 0; n < interface_declaration -> NumNestedInterfaces(); n++)
    {
        if (interface_declaration -> NestedInterface(n) -> semantic_environment)
            ProcessExecutableBodies(interface_declaration -> NestedInterface(n));
    }

    state_stack.Pop();

    return;
}

#ifdef    HAVE_JIKES_NAMESPACE
}            // Close namespace Jikes block
#endif