private string TryReduceBranch(BasicBlock root, BranchBasicBlock branchbb)
{
var beforeState = branchbb.Block.BeforeState;
var afterState = branchbb.Block.AfterState;
{
// While-do
var thenbb = branchbb.Target as JumpBasicBlock;
var group = new Set<BasicBlock> { branchbb };
if (thenbb != null && thenbb.Target.Equals(branchbb) && thenbb.Sources.Count == 1 && group.Add(thenbb) &&
!group.Contains(branchbb.Fallthrough))
{
var instructions = branchbb.Block.CopyContents();
branchbb.Test.Eval(instructions, afterState, thenbb.Block.BeforeState, BottomPT);
var wdi = new WhileDoInstruction
(NextInstructionId--, new Instructions(beforeState, instructions), thenbb.Block)
{
BeforeState = beforeState,
AfterState = branchbb.Fallthrough.Block.BeforeState
};
var newbb = new JumpBasicBlock(nextBlockId++, new Instructions(wdi), branchbb.Fallthrough);
root.Coalesce(branchbb, group, newbb);
return String.Format("while-do from B{0}", branchbb.Id);
}
}
{
// Flipped while-do
var elsebb = branchbb.Fallthrough as JumpBasicBlock;
var group = new Set<BasicBlock> { branchbb };
if (elsebb != null && elsebb.Target.Equals(branchbb) && elsebb.Sources.Count == 1 && group.Add(elsebb) &&
!group.Contains(branchbb.Target))
{
var instructions = branchbb.Block.CopyContents();
branchbb.Test.Negate().Eval
(instructions, afterState, elsebb.Block.BeforeState, BottomPT);
var wdi = new WhileDoInstruction
(NextInstructionId--, new Instructions(beforeState, instructions), elsebb.Block)
{
BeforeState = beforeState,
AfterState = branchbb.Target.Block.BeforeState
};
var newbb = new JumpBasicBlock(nextBlockId++, new Instructions(wdi), branchbb.Target);
root.Coalesce(branchbb, group, newbb);
return String.Format("while-do (flipped) from B{0}", branchbb.Id);
}
}
{
// Do-while
var thenbb = branchbb.Target;
if (thenbb.Equals(branchbb) && !branchbb.Fallthrough.Equals(branchbb))
{
var instructions = branchbb.Block.CopyContents();
branchbb.Test.Eval(instructions, afterState, beforeState, BottomPT);
var cond = SeparateCondition(beforeState, ref instructions);
var dwi = new DoWhileInstruction(NextInstructionId--, new Instructions(beforeState, instructions), cond)
{
BeforeState = beforeState,
AfterState = branchbb.Fallthrough.Block.BeforeState
};
var newbb = new JumpBasicBlock(nextBlockId++, new Instructions(dwi), branchbb.Fallthrough);
root.Coalesce(branchbb, new Set<BasicBlock> { branchbb }, newbb);
return String.Format("do-while from B{0}", branchbb.Id);
}
}
{
// Flipped Do-while
var elsebb = branchbb.Fallthrough;
if (elsebb.Equals(branchbb) && !branchbb.Target.Equals(branchbb))
{
var instructions = branchbb.Block.CopyContents();
branchbb.Test.Negate().Eval
(instructions, afterState, beforeState, BottomPT);
var cond = SeparateCondition(beforeState, ref instructions);
var dwi = new DoWhileInstruction(NextInstructionId--, new Instructions(beforeState, instructions), cond)
{
BeforeState = beforeState,
AfterState = branchbb.Target.Block.BeforeState
};
var newbb = new JumpBasicBlock(nextBlockId++, new Instructions(dwi), branchbb.Target);
root.Coalesce(branchbb, new Set<BasicBlock> { branchbb }, newbb);
return String.Format("do-while (flipped) from B{0}", branchbb.Id);
}
}
{
// If-then, converging control
var thenbb = branchbb.Target as JumpBasicBlock;
if (thenbb != null && thenbb.Target.Equals(branchbb.Fallthrough) && thenbb.Sources.Count == 1)
{
var instructions = branchbb.Block.CopyContents();
branchbb.Test.Eval(instructions, afterState, thenbb.Block.BeforeState, BottomPT);
var cond = SeparateCondition(beforeState, ref instructions);
var itei = new IfThenElseInstruction(NextInstructionId--, cond, thenbb.Block, null)
{ BeforeState = beforeState, AfterState = thenbb.Block.AfterState };
instructions.Add(itei);
var newbb = thenbb.CloneWithInstructions
(nextBlockId++, new Instructions(beforeState, instructions));
root.Coalesce(branchbb, new Set<BasicBlock> { branchbb, thenbb }, newbb);
return String.Format("if-then with converging control paths from B{0}", branchbb.Id);
}
}
{
// Flipped if-then, converging control
var elsebb = branchbb.Fallthrough as JumpBasicBlock;
if (elsebb != null && elsebb.Target.Equals(branchbb.Target) && elsebb.Sources.Count == 1)
{
var instructions = branchbb.Block.CopyContents();
branchbb.Test.Negate().Eval
(instructions, afterState, elsebb.Block.BeforeState, BottomPT);
var cond = SeparateCondition(beforeState, ref instructions);
var itei = new IfThenElseInstruction(NextInstructionId--, cond, elsebb.Block, null)
{ BeforeState = beforeState, AfterState = elsebb.Block.AfterState };
instructions.Add(itei);
var newbb = elsebb.CloneWithInstructions
(nextBlockId++, new Instructions(beforeState, instructions));
root.Coalesce(branchbb, new Set<BasicBlock> { branchbb, elsebb }, newbb);
return String.Format("if-then (flipped) with converging control paths from B{0}", branchbb.Id);
}
}
{
// Short-circuited and/or "expression"
var thenbb = branchbb.Target as JumpBasicBlock;
var elsebb = branchbb.Fallthrough as JumpBasicBlock;
var group = new Set<BasicBlock> { branchbb };
if (thenbb != null && elsebb != null && thenbb.Target.Equals(elsebb.Target) &&
elsebb.Sources.Count == 1 && group.Add(elsebb) && !group.Contains(thenbb) &&
!group.Contains(thenbb.Target) && !thenbb.Target.Equals(thenbb) &&
IsLoadBooleanBlock(thenbb.Block))
{
var instructions = branchbb.Block.CopyContents();
var test = IsLoadTrueBooleanBlock(thenbb.Block) ? branchbb.Test : branchbb.Test.Negate();
test.Eval(instructions, afterState, thenbb.Block.BeforeState, BottomPT);
var left = SeparateCondition(beforeState, ref instructions);
var op = IsLoadTrueBooleanBlock(thenbb.Block) ? ShortCircuitingOp.Or : ShortCircuitingOp.And;
var sci = new ShortCircuitingInstruction(NextInstructionId--, left, op, elsebb.Block)
{ BeforeState = beforeState, AfterState = elsebb.Block.AfterState };
instructions.Add(sci);
var newbb = new JumpBasicBlock
(nextBlockId++, new Instructions(beforeState, instructions), elsebb.Target);
if (thenbb.Sources.Count == 1)
group.Add(thenbb);
root.Coalesce(branchbb, group, newbb);
return String.Format("short-circuited and/or expression from B{0}", branchbb.Id);
}
}
{
// Flipped short-circuited and/or "expression"
var thenbb = branchbb.Target as JumpBasicBlock;
var elsebb = branchbb.Fallthrough as JumpBasicBlock;
var group = new Set<BasicBlock> { branchbb };
if (thenbb != null && elsebb != null && thenbb.Target.Equals(elsebb.Target) &&
thenbb.Sources.Count == 1 && group.Add(thenbb) && !group.Contains(elsebb) &&
!group.Contains(elsebb.Target) && !elsebb.Target.Equals(elsebb) &&
IsLoadBooleanBlock(elsebb.Block))
{
var instructions = branchbb.Block.CopyContents();
var test = IsLoadTrueBooleanBlock(elsebb.Block) ? branchbb.Test.Negate() : branchbb.Test;
test.Eval(instructions, afterState, thenbb.Block.BeforeState, BottomPT);
var left = SeparateCondition(beforeState, ref instructions);
var op = IsLoadTrueBooleanBlock(elsebb.Block) ? ShortCircuitingOp.Or : ShortCircuitingOp.And;
var sci = new ShortCircuitingInstruction(NextInstructionId--, left, op, thenbb.Block)
{ BeforeState = beforeState, AfterState = thenbb.Block.AfterState };
instructions.Add(sci);
var newbb = new JumpBasicBlock
(nextBlockId++, new Instructions(beforeState, instructions), thenbb.Target);
if (elsebb.Sources.Count == 1)
group.Add(elsebb);
root.Coalesce(branchbb, group, newbb);
return String.Format("short-circuited (flipped) and/or expression from B{0}", branchbb.Id);
}
}
{
// Short-circuited and/or control flow
var group = new Set<BasicBlock> { branchbb };
var thenbb = branchbb.Target as BranchBasicBlock;
if (thenbb != null && branchbb.Fallthrough.Equals(thenbb.Fallthrough) && thenbb.Sources.Count == 1 &&
group.Add(thenbb) && !group.Contains(thenbb.Target) && !group.Contains(branchbb.Fallthrough))
{
var instructions = branchbb.Block.CopyContents();
branchbb.Test.Eval(instructions, afterState, thenbb.Block.BeforeState, BottomPT);
var left = SeparateCondition(beforeState, ref instructions);
var instructions2 = thenbb.Block.CopyContents();
var afterState2 = thenbb.Test.Eval
(instructions2, thenbb.Block.AfterState, thenbb.Target.Block.BeforeState, BottomPT);
var right = new Instructions(thenbb.Block.BeforeState, instructions2);
var sci = new ShortCircuitingInstruction(NextInstructionId--, left, ShortCircuitingOp.And, right)
{ BeforeState = beforeState, AfterState = afterState2 };
instructions.Add(sci);
var newbb = new BranchBasicBlock
(nextBlockId++,
new Instructions(beforeState, instructions),
new Test(TestOp.True, false, methEnv.Global.Int32Ref))
{ Target = thenbb.Target, Fallthrough = thenbb.Fallthrough };
root.Coalesce(branchbb, group, newbb);
return String.Format
("short-circuited (normal, normal) and/or control flow from B{0}", branchbb.Id);
}
}
{
// Short-circuited and/or control flow, flipped first
var group = new Set<BasicBlock> { branchbb };
var elsebb = branchbb.Fallthrough as BranchBasicBlock;
if (elsebb != null && branchbb.Target.Equals(elsebb.Fallthrough) && elsebb.Sources.Count == 1 &&
group.Add(elsebb) && !group.Contains(elsebb.Target) && !group.Contains(branchbb.Target))
{
var instructions = branchbb.Block.CopyContents();
branchbb.Test.Negate().Eval
(instructions, afterState, elsebb.Block.BeforeState, BottomPT);
var left = SeparateCondition(beforeState, ref instructions);
var instructions2 = elsebb.Block.CopyContents();
var afterState2 = elsebb.Test.Eval
(instructions2, elsebb.Block.AfterState, elsebb.Target.Block.BeforeState, BottomPT);
var right = new Instructions(elsebb.Block.BeforeState, instructions2);
var sci = new ShortCircuitingInstruction(NextInstructionId--, left, ShortCircuitingOp.And, right)
{ BeforeState = beforeState, AfterState = afterState2 };
instructions.Add(sci);
var newbb = new BranchBasicBlock
(nextBlockId++,
new Instructions(beforeState, instructions),
new Test(TestOp.True, false, methEnv.Global.Int32Ref))
{ Target = elsebb.Target, Fallthrough = branchbb.Target };
root.Coalesce(branchbb, group, newbb);
return String.Format
("short-circuited (flipped, normal) and/or control flow from B{0}", branchbb.Id);
}
}
{
// Short-circuited and/or control flow, flipped second
var group = new Set<BasicBlock> { branchbb };
var thenbb = branchbb.Target as BranchBasicBlock;
if (thenbb != null && branchbb.Fallthrough.Equals(thenbb.Target) && thenbb.Sources.Count == 1 &&
group.Add(thenbb) && !group.Contains(thenbb.Fallthrough) && !group.Contains(branchbb.Fallthrough))
{
var instructions = branchbb.Block.CopyContents();
branchbb.Test.Eval(instructions, afterState, thenbb.Block.BeforeState, BottomPT);
var left = SeparateCondition(beforeState, ref instructions);
var instructions2 = thenbb.Block.CopyContents();
var afterState2 = thenbb.Test.Negate().Eval
(instructions2, thenbb.Block.AfterState, thenbb.Fallthrough.Block.BeforeState, BottomPT);
var right = new Instructions(thenbb.Block.BeforeState, instructions2);
var sci = new ShortCircuitingInstruction(NextInstructionId--, left, ShortCircuitingOp.And, right)
{ BeforeState = beforeState, AfterState = afterState2 };
instructions.Add(sci);
var newbb = new BranchBasicBlock
(nextBlockId++,
new Instructions(beforeState, instructions),
new Test(TestOp.True, false, methEnv.Global.Int32Ref))
{ Target = thenbb.Fallthrough, Fallthrough = branchbb.Fallthrough };
root.Coalesce(branchbb, group, newbb);
return String.Format
("short-circuited (normal, flipped) and/or control flow from B{0}", branchbb.Id);
}
}
{
// Short-circuited and/or control flow, flipped first and second
var group = new Set<BasicBlock> { branchbb };
var elsebb = branchbb.Fallthrough as BranchBasicBlock;
if (elsebb != null && branchbb.Target.Equals(elsebb.Target) && elsebb.Sources.Count == 1 &&
group.Add(elsebb) && !group.Contains(elsebb.Fallthrough) && !group.Contains(branchbb.Target))
{
var instructions = branchbb.Block.CopyContents();
branchbb.Test.Negate().Eval
(instructions, afterState, elsebb.Block.BeforeState, BottomPT);
var left = SeparateCondition(beforeState, ref instructions);
var instructions2 = elsebb.Block.CopyContents();
var afterState2 = elsebb.Test.Negate().Eval
(instructions2, elsebb.Block.AfterState, elsebb.Fallthrough.Block.BeforeState, BottomPT);
var right = new Instructions(elsebb.Block.BeforeState, instructions2);
var sci = new ShortCircuitingInstruction(NextInstructionId--, left, ShortCircuitingOp.And, right)
{ BeforeState = beforeState, AfterState = afterState2 };
instructions.Add(sci);
var newbb = new BranchBasicBlock
(nextBlockId++,
new Instructions(beforeState, instructions),
new Test(TestOp.True, false, methEnv.Global.Int32Ref))
{ Target = elsebb.Fallthrough, Fallthrough = branchbb.Target };
root.Coalesce(branchbb, group, newbb);
return String.Format
("short-circuited (flipped, flipped) and/or control flow from B{0}", branchbb.Id);
}
}
{
// If-then-else, neither side returns
var thenbb = branchbb.Target as NonReturningBasicBlock;
var elsebb = branchbb.Fallthrough as NonReturningBasicBlock;
if (thenbb != null && elsebb != null && !branchbb.Equals(thenbb) && !branchbb.Equals(elsebb) &&
!thenbb.Equals(elsebb) && branchbb.Target.Sources.Count == 1 &&
branchbb.Fallthrough.Sources.Count == 1)
{
var instructions = branchbb.Block.CopyContents();
if (thenbb.Block.Size <= elsebb.Block.Size)
{
branchbb.Test.Eval
(instructions, afterState, thenbb.Block.BeforeState, BottomPT);
var cond = SeparateCondition(beforeState, ref instructions);
var itei = new IfThenElseInstruction(NextInstructionId--, cond, thenbb.Block, null)
{ BeforeState = beforeState, AfterState = thenbb.Block.AfterState };
instructions.Add(itei);
var newbb = new JumpBasicBlock
(nextBlockId++, new Instructions(beforeState, instructions), elsebb);
root.Coalesce(branchbb, new Set<BasicBlock> { branchbb, thenbb }, newbb);
return String.Format("if-then-else, no return, then smaller, from B{0}", branchbb.Id);
}
else
{
branchbb.Test.Negate().Eval
(instructions, afterState, elsebb.Block.BeforeState, BottomPT);
var cond = SeparateCondition(beforeState, ref instructions);
var itei = new IfThenElseInstruction(NextInstructionId--, cond, elsebb.Block, null)
{ BeforeState = beforeState, AfterState = elsebb.Block.AfterState };
instructions.Add(itei);
var newbb = new JumpBasicBlock
(nextBlockId++, new Instructions(beforeState, instructions), thenbb);
root.Coalesce(branchbb, new Set<BasicBlock> { branchbb, elsebb }, newbb);
return String.Format("if-then-else, no return, else smaller, from B{0}", branchbb.Id);
}
}
}
{
// If-then, no-return
var thenbb = branchbb.Target as NonReturningBasicBlock;
if (thenbb != null && thenbb.Sources.Count == 1)
{
var instructions = branchbb.Block.CopyContents();
branchbb.Test.Eval(instructions, afterState, thenbb.Block.BeforeState, BottomPT);
var cond = SeparateCondition(beforeState, ref instructions);
var itei = new IfThenElseInstruction(NextInstructionId--, cond, thenbb.Block, null)
{ BeforeState = beforeState, AfterState = thenbb.Block.AfterState };
instructions.Add(itei);
var newbb = new JumpBasicBlock
(nextBlockId++, new Instructions(beforeState, instructions), branchbb.Fallthrough);
root.Coalesce(branchbb, new Set<BasicBlock> { branchbb, thenbb }, newbb);
return String.Format("if-then, no return, from B{0}", branchbb.Id);
}
}
{
// Flipped if-then, no-return
var elsebb = branchbb.Fallthrough as NonReturningBasicBlock;
if (elsebb != null && elsebb.Sources.Count == 1)
{
var instructions = branchbb.Block.CopyContents();
branchbb.Test.Negate().Eval
(instructions, afterState, elsebb.Block.BeforeState, BottomPT);
var cond = SeparateCondition(beforeState, ref instructions);
var itei = new IfThenElseInstruction(NextInstructionId--, cond, elsebb.Block, null)
{ BeforeState = beforeState, AfterState = elsebb.Block.AfterState };
instructions.Add(itei);
var newbb = new JumpBasicBlock
(nextBlockId++, new Instructions(beforeState, instructions), branchbb.Target);
root.Coalesce(branchbb, new Set<BasicBlock> { branchbb, elsebb }, newbb);
return String.Format("if-then (flipped), no return, from B{0}", branchbb.Id);
}
}
{
// If-then-else
var group = new Set<BasicBlock> { branchbb };
if (group.Add(branchbb.Target) && group.Add(branchbb.Fallthrough) &&
branchbb.Target.Sources.Count == 1 && branchbb.Fallthrough.Sources.Count == 1 &&
branchbb.Target.HasSameExit(branchbb.Fallthrough))
{
var instructions = branchbb.Block.CopyContents();
branchbb.Test.Eval
(instructions, afterState, branchbb.Target.Block.BeforeState, BottomPT);
var cond = SeparateCondition(beforeState, ref instructions);
var itei = new IfThenElseInstruction
(NextInstructionId--, cond, branchbb.Target.Block, branchbb.Fallthrough.Block)
{
BeforeState = beforeState,
AfterState = branchbb.Target.Block.AfterState
};
instructions.Add(itei);
var newbb = branchbb.Fallthrough.CloneWithInstructions
(nextBlockId++, new Instructions(beforeState, instructions));
root.Coalesce(branchbb, group, newbb);
return String.Format("if-then-else from B{0}", branchbb.Id);
}
}
return null;
}
private void BreakReduceBranch(BasicBlock root, BBLoop loop, BasicBlock breakTarget, BranchBasicBlock branchbb, Seq<BasicBlock> removed, Seq<BasicBlock> added)
{
var beforeState = branchbb.Block.BeforeState;
var afterState = branchbb.Block.AfterState;
if (branchbb.Target.Equals(breakTarget) && !branchbb.Fallthrough.Equals(breakTarget))
{
var instructions = branchbb.Block.CopyContents();
branchbb.Test.Eval(instructions, afterState, branchbb.Target.Block.BeforeState, BottomPT);
var cond = SeparateCondition(beforeState, ref instructions);
var lci = new BreakContinueInstruction(NextInstructionId--, BreakContinueOp.Break, loop.Label)
{ BeforeState = afterState, AfterState = afterState };
var itei = new IfThenElseInstruction(NextInstructionId--, cond, new Instructions(lci), null)
{ BeforeState = beforeState, AfterState = afterState };
instructions.Add(itei);
var newbb = new JumpBasicBlock(nextBlockId++, new Instructions(beforeState, instructions), branchbb.Fallthrough);
root.Coalesce(branchbb, new Set<BasicBlock> { branchbb }, newbb);
removed.Add(branchbb);
added.Add(newbb);
}
else if (branchbb.Fallthrough.Equals(breakTarget) && !branchbb.Target.Equals(breakTarget))
{
var instructions = branchbb.Block.CopyContents();
branchbb.Test.Negate().Eval
(instructions, afterState, branchbb.Fallthrough.Block.BeforeState, BottomPT);
var cond = SeparateCondition(beforeState, ref instructions);
var lci = new BreakContinueInstruction(NextInstructionId--, BreakContinueOp.Break, loop.Label)
{ BeforeState = afterState, AfterState = afterState };
var itei = new IfThenElseInstruction(NextInstructionId--, cond, new Instructions(lci), null)
{ BeforeState = beforeState, AfterState = afterState };
instructions.Add(itei);
var newbb = new JumpBasicBlock(nextBlockId++, new Instructions(beforeState, instructions), branchbb.Target);
root.Coalesce(branchbb, new Set<BasicBlock> { branchbb }, newbb);
removed.Add(branchbb);
added.Add(newbb);
}
}
private BasicBlock BasicBlockFromIndex(int start, Context context)
{
if (start >= context.Block.Count)
throw new InvalidOperationException("run off of end of instructions");
var offset = context.Block[start].Offset;
var i = start;
Func<int, Instructions> extractInclusive = j => context.Block.Peephole(start, j - start + 1, tracer);
Func<int, Instructions> extractExclusive = j => context.Block.Peephole(start, j - start, tracer);
while (i < context.Block.Count)
{
var instruction = context.Block[i];
if (i > start && targets.Contains(instruction.Offset))
{
var jbb = new JumpBasicBlock(nextBlockId++, extractExclusive(i));
context.OffsetToBlock.Add(offset, jbb);
jbb.Target = BasicBlockFromLocalTarget(instruction.Offset, context);
jbb.Target.Sources.Add(jbb);
return jbb;
}
else
{
switch (instruction.Flavor)
{
case InstructionFlavor.Misc:
{
var misci = (MiscInstruction)instruction;
switch (misci.Op)
{
case MiscOp.Throw:
{
var nrbb = new NonReturningBasicBlock(nextBlockId++, extractInclusive(i));
context.OffsetToBlock.Add(offset, nrbb);
return nrbb;
}
case MiscOp.Rethrow:
{
var handlerContext = context as HandlerContext;
if (handlerContext == null ||
!(handlerContext.ILHandler is CatchTryInstructionHandler))
throw new InvalidOperationException("rethrow not within catch");
var nrbb = new NonReturningBasicBlock(nextBlockId++, extractInclusive(i));
context.OffsetToBlock.Add(offset, nrbb);
return nrbb;
}
case MiscOp.Ret:
case MiscOp.RetVal:
{
if (context is TryContext || context is HandlerContext)
throw new InvalidOperationException("return within a try or handler block");
var nrbb = new NonReturningBasicBlock(nextBlockId++, extractInclusive(i));
context.OffsetToBlock.Add(offset, nrbb);
return nrbb;
}
case MiscOp.Endfinally:
{
var handlerContext = context as HandlerContext;
if (handlerContext == null)
throw new InvalidOperationException
("endfinally not within fault/finally block");
switch (handlerContext.ILHandler.Flavor)
{
case HandlerFlavor.Catch:
case HandlerFlavor.Filter:
throw new InvalidOperationException
("endfinally not within fault/finally block");
case HandlerFlavor.Fault:
{
var efbb = new EndFaultBasicBlock
(nextBlockId++,
extractExclusive(i),
(TBBFaultHandler)handlerContext.TBBHandler);
context.OffsetToBlock.Add(offset, efbb);
return efbb;
}
case HandlerFlavor.Finally:
{
var efbb = new EndFinallyBasicBlock
(nextBlockId++,
extractExclusive(i),
(TBBFinallyHandler)handlerContext.TBBHandler,
misci.BeforeState.Depth);
context.OffsetToBlock.Add(offset, efbb);
return efbb;
}
default:
throw new ArgumentOutOfRangeException();
}
}
default:
break;
}
break;
}
case InstructionFlavor.Branch:
{
var bri = (BranchInstruction)instruction;
switch (bri.Op)
{
case BranchOp.Br:
{
var jbb = new JumpBasicBlock(nextBlockId++, extractExclusive(i));
context.OffsetToBlock.Add(offset, jbb);
jbb.Target = BasicBlockFromLocalTarget(bri.Target, context);
jbb.Target.Sources.Add(jbb);
return jbb;
}
case BranchOp.Brtrue:
case BranchOp.Brfalse:
case BranchOp.Breq:
case BranchOp.Brne:
case BranchOp.BrLt:
case BranchOp.BrLe:
case BranchOp.BrGt:
case BranchOp.BrGe:
{
if (i + 1 >= context.Block.Count)
throw new InvalidOperationException("run off end of instructions");
var bbb = new BranchBasicBlock
(nextBlockId++,
extractExclusive(i),
Test.FromBranchOp(bri.Op, bri.IsUnsigned, bri.Type));
context.OffsetToBlock.Add(offset, bbb);
bbb.Target = BasicBlockFromLocalTarget(bri.Target, context);
bbb.Target.Sources.Add(bbb);
bbb.Fallthrough = BasicBlockFromLocalTarget(context.Block[i + 1].Offset, context);
if (!bbb.Fallthrough.Equals(bbb.Target))
bbb.Fallthrough.Sources.Add(bbb);
return bbb;
}
case BranchOp.Leave:
{
var handlerPopCount = default(int);
var stackPopCount = bri.BeforeState.Depth;
var leftContext = default(bool);
var bb = BasicBlockFromTarget
(bri.Target, context, out leftContext, out handlerPopCount);
if (!leftContext)
{
// Not leaving try or handler block, so just empty stack and branch
var lbb = new LeaveBasicBlock
(nextBlockId++, extractExclusive(i), stackPopCount);
context.OffsetToBlock.Add(offset, lbb);
lbb.Target = bb;
lbb.Target.Sources.Add(lbb);
return lbb;
}
else
{
var tryContext = context as TryContext;
if (tryContext != null)
{
// Poping at least one exception handler and branching
var ltbb = new LeaveTryBasicBlock
(nextBlockId++,
extractExclusive(i),
tryContext.TryBasicBlock,
handlerPopCount,
stackPopCount);
context.OffsetToBlock.Add(offset, ltbb);
ltbb.Target = bb;
ltbb.Target.Sources.Add(ltbb);
return ltbb;
}
else
{
var handlerContext = context as HandlerContext;
if (handlerContext != null)
{
switch (handlerContext.ILHandler.Flavor)
{
case HandlerFlavor.Catch:
{
// Poping zero or more exception handlers and branching
var lcbb = new LeaveCatchBasicBlock
(nextBlockId++,
extractExclusive(i),
(TBBCatchHandler)handlerContext.TBBHandler,
handlerPopCount,
stackPopCount);
lcbb.Target = bb;
lcbb.Target.Sources.Add(lcbb);
return lcbb;
}
case HandlerFlavor.Filter:
throw new NotSupportedException("filter");
case HandlerFlavor.Fault:
throw new InvalidOperationException("leaving fault block");
case HandlerFlavor.Finally:
throw new InvalidOperationException("leaving finally block");
default:
throw new ArgumentOutOfRangeException();
}
}
else
throw new InvalidOperationException
("no try or handler context to leave");
}
}
}
default:
throw new ArgumentOutOfRangeException();
}
}
case InstructionFlavor.Switch:
{
if (i + 1 >= context.Block.Count)
throw new InvalidOperationException("run off end of instructions");
var switchi = (SwitchInstruction)instruction;
var sbb = new SwitchBasicBlock(nextBlockId++, extractExclusive(i));
context.OffsetToBlock.Add(offset, sbb);
var seen = new Set<BasicBlock>();
foreach (var t in switchi.CaseTargets)
{
var target = BasicBlockFromLocalTarget(t, context);
sbb.CaseTargets.Add(target);
if (!seen.Contains(target))
{
target.Sources.Add(sbb);
seen.Add(target);
}
}
sbb.Fallthrough = BasicBlockFromLocalTarget(context.Block[i + 1].Offset, context);
if (!seen.Contains(sbb.Fallthrough))
sbb.Fallthrough.Sources.Add(sbb);
return sbb;
}
case InstructionFlavor.Try:
{
// Try is known to be a target, thus i == start and extract(i) would yield empty
var tryi = (TryInstruction)instruction;
var parent = default(TryBasicBlock);
var tryContext = context as TryContext;
if (tryContext != null)
parent = tryContext.TryBasicBlock;
else
{
var handlerContext = context as HandlerContext;
if (handlerContext != null)
parent = handlerContext.TryContext.TryBasicBlock;
}
var tbb = new TryBasicBlock(nextBlockId++, parent, instruction.BeforeState);
context.OffsetToBlock.Add(offset, tbb);
var subTryContext = new TryContext(tryi.Body, context, tbb);
tbb.Body = BasicBlockFromInstructions(subTryContext);
tbb.Body.Sources.Add(tbb);
foreach (var ilHandler in tryi.Handlers)
{
var tbbHandler = default(TBBHandler);
switch (ilHandler.Flavor)
{
case HandlerFlavor.Catch:
{
var catchh = (CatchTryInstructionHandler)ilHandler;
tbbHandler = new TBBCatchHandler(tbb, catchh.Type);
break;
}
case HandlerFlavor.Filter:
throw new NotSupportedException("filter blocks");
case HandlerFlavor.Fault:
{
tbbHandler = new TBBFaultHandler(tbb);
break;
}
case HandlerFlavor.Finally:
{
tbbHandler = new TBBFinallyHandler(tbb);
break;
}
default:
throw new ArgumentOutOfRangeException();
}
var subHandlerContext = new HandlerContext
(ilHandler.Body, ilHandler, subTryContext, tbbHandler);
tbbHandler.Body = BasicBlockFromInstructions(subHandlerContext);
tbbHandler.Body.Sources.Add(tbb);
tbb.Handlers.Add(tbbHandler);
}
return tbb;
}
default:
break;
}
i++;
}
}
throw new InvalidOperationException("ran off of end of instructions");
}
private string ContinueReduceBranch(BasicBlock root, BBLoop loop, BranchBasicBlock branchbb)
{
var beforeState = branchbb.Block.BeforeState;
var afterState = branchbb.Block.AfterState;
if (branchbb.Target.Equals(loop.ContinueTarget) && !branchbb.Fallthrough.Equals(loop.ContinueTarget) &&
loop.ContinueTarget.Sources.Count > 1)
{
var instructions = branchbb.Block.CopyContents();
branchbb.Test.Eval
(instructions, afterState, branchbb.Target.Block.BeforeState, BottomPT);
var cond = SeparateCondition(beforeState, ref instructions);
var lci = new BreakContinueInstruction(NextInstructionId--, BreakContinueOp.Continue, loop.Label)
{ BeforeState = afterState, AfterState = afterState };
var ifei = new IfThenElseInstruction(-1, cond, new Instructions(lci), null)
{ BeforeState = beforeState, AfterState = afterState };
instructions.Add(ifei);
var newbb = new JumpBasicBlock
(nextBlockId++, new Instructions(beforeState, instructions), branchbb.Fallthrough);
root.Coalesce(branchbb, new Set<BasicBlock> { branchbb }, newbb);
return String.Format("continue from branch at B{0} within loop from B{1}", branchbb.Id, loop.Head.Id);
}
if (branchbb.Fallthrough.Equals(loop.ContinueTarget) && !branchbb.Target.Equals(loop.ContinueTarget) &&
loop.ContinueTarget.Sources.Count > 1)
{
var instructions = branchbb.Block.CopyContents();
branchbb.Test.Negate().Eval
(instructions, afterState, branchbb.Fallthrough.Block.BeforeState, BottomPT);
var cond = SeparateCondition(beforeState, ref instructions);
var lci = new BreakContinueInstruction(NextInstructionId--, BreakContinueOp.Continue, loop.Label)
{ BeforeState = afterState, AfterState = afterState };
var ifei = new IfThenElseInstruction(NextInstructionId--, cond, new Instructions(lci), null)
{ BeforeState = beforeState, AfterState = afterState };
instructions.Add(ifei);
var newbb = new JumpBasicBlock(nextBlockId++, new Instructions(beforeState, instructions), branchbb.Target);
root.Coalesce(branchbb, new Set<BasicBlock> { branchbb }, newbb);
return String.Format
("continue from branch (flipped) at B{0} within loop from B{1}", branchbb.Id, loop.Head.Id);
}
return null;
}
