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diff --git a/ICSharpCode.Decompiler/Ast/Transforms/AddCheckedBlocks.cs b/ICSharpCode.Decompiler/Ast/Transforms/AddCheckedBlocks.cs
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-// Copyright (c) 2011 AlphaSierraPapa for the SharpDevelop Team
-//
-// Permission is hereby granted, free of charge, to any person obtaining a copy of this
-// software and associated documentation files (the "Software"), to deal in the Software
-// without restriction, including without limitation the rights to use, copy, modify, merge,
-// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
-// to whom the Software is furnished to do so, subject to the following conditions:
-//
-// The above copyright notice and this permission notice shall be included in all copies or
-// substantial portions of the Software.
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
-// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
-// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
-// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
-// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
-// DEALINGS IN THE SOFTWARE.
-
-using System;
-using System.Linq;
-using ICSharpCode.Decompiler.ILAst;
-using ICSharpCode.NRefactory.CSharp;
-
-namespace ICSharpCode.Decompiler.Ast.Transforms
-{
- /// <summary>
- /// Add checked/unchecked blocks.
- /// </summary>
- public class AddCheckedBlocks : IAstTransform
- {
- #region Annotation
- sealed class CheckedUncheckedAnnotation {
- /// <summary>
- /// true=checked, false=unchecked
- /// </summary>
- public bool IsChecked;
- }
-
- public static readonly object CheckedAnnotation = new CheckedUncheckedAnnotation { IsChecked = true };
- public static readonly object UncheckedAnnotation = new CheckedUncheckedAnnotation { IsChecked = false };
- #endregion
-
- /*
- We treat placing checked/unchecked blocks as an optimization problem, with the following goals:
- 1. Use minimum number of checked blocks+expressions
- 2. Prefer checked expressions over checked blocks
- 3. Make the scope of checked expressions as small as possible
- 4. Open checked blocks as late as possible, and close checked blocks as late as possible
- (where goal 1 has the highest priority)
-
- Goal 4a (open checked blocks as late as possible) is necessary so that we don't move variable declarations
- into checked blocks, as the variable might still be used after the checked block.
- (this could cause DeclareVariables to omit the variable declaration, producing incorrect code)
- Goal 4b (close checked blocks as late as possible) makes the code look nicer in this case:
- checked {
- int c = a + b;
- int r = a + c;
- return r;
- }
- If the checked block was closed as early as possible, the variable r would have to be declared outside
- (this would work, but look badly)
- */
-
- #region struct Cost
- struct Cost
- {
- // highest possible cost so that the Blocks+Expressions addition doesn't overflow
- public static readonly Cost Infinite = new Cost(0x3fffffff, 0x3fffffff);
-
- public readonly int Blocks;
- public readonly int Expressions;
-
- public Cost(int blocks, int expressions)
- {
- Blocks = blocks;
- Expressions = expressions;
- }
-
- public static bool operator <(Cost a, Cost b)
- {
- return a.Blocks + a.Expressions < b.Blocks + b.Expressions
- || a.Blocks + a.Expressions == b.Blocks + b.Expressions && a.Blocks < b.Blocks;
- }
-
- public static bool operator >(Cost a, Cost b)
- {
- return a.Blocks + a.Expressions > b.Blocks + b.Expressions
- || a.Blocks + a.Expressions == b.Blocks + b.Expressions && a.Blocks > b.Blocks;
- }
-
- public static bool operator <=(Cost a, Cost b)
- {
- return a.Blocks + a.Expressions < b.Blocks + b.Expressions
- || a.Blocks + a.Expressions == b.Blocks + b.Expressions && a.Blocks <= b.Blocks;
- }
-
- public static bool operator >=(Cost a, Cost b)
- {
- return a.Blocks + a.Expressions > b.Blocks + b.Expressions
- || a.Blocks + a.Expressions == b.Blocks + b.Expressions && a.Blocks >= b.Blocks;
- }
-
- public static Cost operator +(Cost a, Cost b)
- {
- return new Cost(a.Blocks + b.Blocks, a.Expressions + b.Expressions);
- }
-
- public override string ToString()
- {
- return string.Format("[{0} + {1}]", Blocks, Expressions);
- }
- }
- #endregion
-
- #region class InsertedNode
- /// <summary>
- /// Holds the blocks and expressions that should be inserted
- /// </summary>
- abstract class InsertedNode
- {
- public static InsertedNode operator +(InsertedNode a, InsertedNode b)
- {
- if (a == null)
- return b;
- if (b == null)
- return a;
- return new InsertedNodeList(a, b);
- }
-
- public abstract void Insert();
- }
-
- class InsertedNodeList : InsertedNode
- {
- readonly InsertedNode child1, child2;
-
- public InsertedNodeList(InsertedNode child1, InsertedNode child2)
- {
- this.child1 = child1;
- this.child2 = child2;
- }
-
- public override void Insert()
- {
- child1.Insert();
- child2.Insert();
- }
- }
-
- class InsertedExpression : InsertedNode
- {
- readonly Expression expression;
- readonly bool isChecked;
-
- public InsertedExpression(Expression expression, bool isChecked)
- {
- this.expression = expression;
- this.isChecked = isChecked;
- }
-
- public override void Insert()
- {
- if (isChecked)
- expression.ReplaceWith(e => new CheckedExpression { Expression = e });
- else
- expression.ReplaceWith(e => new UncheckedExpression { Expression = e });
- }
- }
-
- class ConvertCompoundAssignment : InsertedNode
- {
- readonly Expression expression;
- readonly bool isChecked;
-
- public ConvertCompoundAssignment(Expression expression, bool isChecked)
- {
- this.expression = expression;
- this.isChecked = isChecked;
- }
-
- public override void Insert()
- {
- AssignmentExpression assign = expression.Annotation<ReplaceMethodCallsWithOperators.RestoreOriginalAssignOperatorAnnotation>().Restore(expression);
- expression.ReplaceWith(assign);
- if (isChecked)
- assign.Right = new CheckedExpression { Expression = assign.Right.Detach() };
- else
- assign.Right = new UncheckedExpression { Expression = assign.Right.Detach() };
- }
- }
-
- class InsertedBlock : InsertedNode
- {
- readonly Statement firstStatement; // inclusive
- readonly Statement lastStatement; // exclusive
- readonly bool isChecked;
-
- public InsertedBlock(Statement firstStatement, Statement lastStatement, bool isChecked)
- {
- this.firstStatement = firstStatement;
- this.lastStatement = lastStatement;
- this.isChecked = isChecked;
- }
-
- public override void Insert()
- {
- BlockStatement newBlock = new BlockStatement();
- // Move all statements except for the first
- Statement next;
- for (Statement stmt = firstStatement.GetNextStatement(); stmt != lastStatement; stmt = next) {
- next = stmt.GetNextStatement();
- newBlock.Add(stmt.Detach());
- }
- // Replace the first statement with the new (un)checked block
- if (isChecked)
- firstStatement.ReplaceWith(new CheckedStatement { Body = newBlock });
- else
- firstStatement.ReplaceWith(new UncheckedStatement { Body = newBlock });
- // now also move the first node into the new block
- newBlock.Statements.InsertAfter(null, firstStatement);
- }
- }
- #endregion
-
- #region class Result
- /// <summary>
- /// Holds the result of an insertion operation.
- /// </summary>
- class Result
- {
- public Cost CostInCheckedContext;
- public InsertedNode NodesToInsertInCheckedContext;
- public Cost CostInUncheckedContext;
- public InsertedNode NodesToInsertInUncheckedContext;
- }
- #endregion
-
- public void Run(AstNode node)
- {
- BlockStatement block = node as BlockStatement;
- if (block == null) {
- for (AstNode child = node.FirstChild; child != null; child = child.NextSibling) {
- Run(child);
- }
- } else {
- Result r = GetResultFromBlock(block);
- if (r.NodesToInsertInUncheckedContext != null)
- r.NodesToInsertInUncheckedContext.Insert();
- }
- }
-
- Result GetResultFromBlock(BlockStatement block)
- {
- // For a block, we are tracking 4 possibilities:
- // a) context is checked, no unchecked block open
- Cost costCheckedContext = new Cost(0, 0);
- InsertedNode nodesCheckedContext = null;
- // b) context is checked, an unchecked block is open
- Cost costCheckedContextUncheckedBlockOpen = Cost.Infinite;
- InsertedNode nodesCheckedContextUncheckedBlockOpen = null;
- Statement uncheckedBlockStart = null;
- // c) context is unchecked, no checked block open
- Cost costUncheckedContext = new Cost(0, 0);
- InsertedNode nodesUncheckedContext = null;
- // d) context is unchecked, a checked block is open
- Cost costUncheckedContextCheckedBlockOpen = Cost.Infinite;
- InsertedNode nodesUncheckedContextCheckedBlockOpen = null;
- Statement checkedBlockStart = null;
-
- Statement statement = block.Statements.FirstOrDefault();
- while (true) {
- // Blocks can be closed 'for free'. We use '<=' so that blocks are closed as late as possible (goal 4b)
- if (costCheckedContextUncheckedBlockOpen <= costCheckedContext) {
- costCheckedContext = costCheckedContextUncheckedBlockOpen;
- nodesCheckedContext = nodesCheckedContextUncheckedBlockOpen + new InsertedBlock(uncheckedBlockStart, statement, false);
- }
- if (costUncheckedContextCheckedBlockOpen <= costUncheckedContext) {
- costUncheckedContext = costUncheckedContextCheckedBlockOpen;
- nodesUncheckedContext = nodesUncheckedContextCheckedBlockOpen + new InsertedBlock(checkedBlockStart, statement, true);
- }
- if (statement == null)
- break;
- // Now try opening blocks. We use '<=' so that blocks are opened as late as possible. (goal 4a)
- if (costCheckedContext + new Cost(1, 0) <= costCheckedContextUncheckedBlockOpen) {
- costCheckedContextUncheckedBlockOpen = costCheckedContext + new Cost(1, 0);
- nodesCheckedContextUncheckedBlockOpen = nodesCheckedContext;
- uncheckedBlockStart = statement;
- }
- if (costUncheckedContext + new Cost(1, 0) <= costUncheckedContextCheckedBlockOpen) {
- costUncheckedContextCheckedBlockOpen = costUncheckedContext + new Cost(1, 0);
- nodesUncheckedContextCheckedBlockOpen = nodesUncheckedContext;
- checkedBlockStart = statement;
- }
- // Now handle the statement
- Result stmtResult = GetResult(statement);
-
- costCheckedContext += stmtResult.CostInCheckedContext;
- nodesCheckedContext += stmtResult.NodesToInsertInCheckedContext;
- costCheckedContextUncheckedBlockOpen += stmtResult.CostInUncheckedContext;
- nodesCheckedContextUncheckedBlockOpen += stmtResult.NodesToInsertInUncheckedContext;
- costUncheckedContext += stmtResult.CostInUncheckedContext;
- nodesUncheckedContext += stmtResult.NodesToInsertInUncheckedContext;
- costUncheckedContextCheckedBlockOpen += stmtResult.CostInCheckedContext;
- nodesUncheckedContextCheckedBlockOpen += stmtResult.NodesToInsertInCheckedContext;
-
- statement = statement.GetNextStatement();
- }
-
- return new Result {
- CostInCheckedContext = costCheckedContext, NodesToInsertInCheckedContext = nodesCheckedContext,
- CostInUncheckedContext = costUncheckedContext, NodesToInsertInUncheckedContext = nodesUncheckedContext
- };
- }
-
- Result GetResult(AstNode node)
- {
- if (node is BlockStatement)
- return GetResultFromBlock((BlockStatement)node);
- Result result = new Result();
- for (AstNode child = node.FirstChild; child != null; child = child.NextSibling) {
- Result childResult = GetResult(child);
- result.CostInCheckedContext += childResult.CostInCheckedContext;
- result.NodesToInsertInCheckedContext += childResult.NodesToInsertInCheckedContext;
- result.CostInUncheckedContext += childResult.CostInUncheckedContext;
- result.NodesToInsertInUncheckedContext += childResult.NodesToInsertInUncheckedContext;
- }
- Expression expr = node as Expression;
- if (expr != null) {
- CheckedUncheckedAnnotation annotation = expr.Annotation<CheckedUncheckedAnnotation>();
- if (annotation != null) {
- // If the annotation requires this node to be in a specific context, add a huge cost to the other context
- // That huge cost gives us the option to ignore a required checked/unchecked expression when there wouldn't be any
- // solution otherwise. (e.g. "for (checked(M().x += 1); true; unchecked(M().x += 2)) {}")
- if (annotation.IsChecked)
- result.CostInUncheckedContext += new Cost(10000, 0);
- else
- result.CostInCheckedContext += new Cost(10000, 0);
- }
- // Embed this node in an checked/unchecked expression:
- if (expr.Parent is ExpressionStatement) {
- // We cannot use checked/unchecked for top-level-expressions.
- // However, we could try converting a compound assignment (checked(a+=b);) or unary operator (checked(a++);)
- // back to its old form.
- if (expr.Annotation<ReplaceMethodCallsWithOperators.RestoreOriginalAssignOperatorAnnotation>() != null) {
- // We use '<' so that expressions are introduced on the deepest level possible (goal 3)
- if (result.CostInCheckedContext + new Cost(1, 1) < result.CostInUncheckedContext) {
- result.CostInUncheckedContext = result.CostInCheckedContext + new Cost(1, 1);
- result.NodesToInsertInUncheckedContext = result.NodesToInsertInCheckedContext + new ConvertCompoundAssignment(expr, true);
- } else if (result.CostInUncheckedContext + new Cost(1, 1) < result.CostInCheckedContext) {
- result.CostInCheckedContext = result.CostInUncheckedContext + new Cost(1, 1);
- result.NodesToInsertInCheckedContext = result.NodesToInsertInUncheckedContext + new ConvertCompoundAssignment(expr, false);
- }
- }
- } else if (expr.Role.IsValid(Expression.Null)) {
- // We use '<' so that expressions are introduced on the deepest level possible (goal 3)
- if (result.CostInCheckedContext + new Cost(0, 1) < result.CostInUncheckedContext) {
- result.CostInUncheckedContext = result.CostInCheckedContext + new Cost(0, 1);
- result.NodesToInsertInUncheckedContext = result.NodesToInsertInCheckedContext + new InsertedExpression(expr, true);
- } else if (result.CostInUncheckedContext + new Cost(0, 1) < result.CostInCheckedContext) {
- result.CostInCheckedContext = result.CostInUncheckedContext + new Cost(0, 1);
- result.NodesToInsertInCheckedContext = result.NodesToInsertInUncheckedContext + new InsertedExpression(expr, false);
- }
- }
- }
- return result;
- }
- }
-}
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