private static bool HasSharedTarget(NodeBlock pred, DJumpCondition jcc)
{
NodeBlock trueTarget = BlockAnalysis.EffectiveTarget(jcc.trueTarget);
if (trueTarget.lir.numPredecessors == 1)
{
return(false);
}
if (pred.lir.idominated.Length > 3)
{
return(true);
}
// Hack... sniff out the case we care about, the true target
// probably having a conditional.
if (trueTarget.lir.instructions.Length == 2 &&
trueTarget.lir.instructions[0].op == Opcode.Constant &&
trueTarget.lir.instructions[1].op == Opcode.Jump)
{
return(true);
}
// Because of edge splitting, there will always be at least 4
// dominators for the immediate dominator of a shared block.
return(false);
}
private void writeDoWhileLoop(WhileLoop loop)
{
outputLine("do" + Environment.NewLine + "{");
increaseIndent();
if (loop.body != null)
{
writeBlock(loop.body);
}
string cond;
if (loop.logic == null)
{
writeStatements(loop.source);
decreaseIndent();
DJumpCondition jcc = (DJumpCondition)loop.source.nodes.last;
cond = buildExpression(jcc.getOperand(0));
}
else
{
decreaseIndent();
cond = buildLogicChain(loop.logic);
}
outputLine("}");
outputLine("while (" + cond + ");");
if (loop.join != null)
{
writeBlock(loop.join);
}
}
public override void visit(DJumpCondition jcc)
{
if (jcc.getOperand(0).type == NodeType.Binary)
{
DBinary binary = (DBinary)jcc.getOperand(0);
propagateInputs(binary.lhs, binary.rhs);
}
}
private void writeIf(IfBlock block)
{
string cond;
if (block.logic == null)
{
writeStatements(block.source);
DJumpCondition jcc = (DJumpCondition)block.source.nodes.last;
if (block.invert)
{
if (jcc.getOperand(0).type == NodeType.Unary &&
((DUnary)jcc.getOperand(0)).spop == SPOpcode.not)
{
cond = buildExpression(jcc.getOperand(0).getOperand(0));
}
else if (jcc.getOperand(0).type == NodeType.Load)
{
cond = "!" + buildExpression(jcc.getOperand(0));
}
else
{
cond = "!(" + buildExpression(jcc.getOperand(0)) + ")";
}
}
else
{
cond = buildExpression(jcc.getOperand(0));
}
}
else
{
cond = buildLogicChain(block.logic);
Debug.Assert(!block.invert);
}
outputLine("if (" + cond + ")");
outputLine("{");
increaseIndent();
writeBlock(block.trueArm);
decreaseIndent();
if (block.falseArm != null &&
BlockAnalysis.GetEmptyTarget(block.falseArm.source) == null)
{
outputLine("}");
outputLine("else");
outputLine("{");
increaseIndent();
writeBlock(block.falseArm);
decreaseIndent();
}
outputLine("}");
if (block.join != null)
{
writeBlock(block.join);
}
}
private IfBlock traverseIf(NodeBlock block, DJumpCondition jcc)
{
if (HasSharedTarget(block, jcc))
{
return(traverseComplexIf(block, jcc));
}
NodeBlock trueTarget = (jcc.spop == SPOpcode.jzer) ? jcc.falseTarget : jcc.trueTarget;
NodeBlock falseTarget = (jcc.spop == SPOpcode.jzer) ? jcc.trueTarget : jcc.falseTarget;
NodeBlock joinTarget = findJoinOfSimpleIf(block, jcc);
// If there is no join block (both arms terminate control flow),
// eliminate one arm and use the other as a join point.
if (joinTarget == null)
{
joinTarget = falseTarget;
}
// If the false target is equivalent to the join point, eliminate
// it.
if (BlockAnalysis.EffectiveTarget(falseTarget) == joinTarget)
{
falseTarget = null;
}
// If the true target is equivalent to the join point, promote
// the false target to the true target and undo the inversion.
bool invert = false;
if (BlockAnalysis.EffectiveTarget(trueTarget) == joinTarget)
{
trueTarget = falseTarget;
falseTarget = null;
invert ^= true;
}
// If there is always a true target and a join target.
pushScope(joinTarget);
ControlBlock trueArm = traverseBlock(trueTarget);
popScope();
ControlBlock joinArm = traverseJoin(joinTarget);
if (falseTarget == null)
{
return(new IfBlock(block, invert, trueArm, joinArm));
}
pushScope(joinTarget);
ControlBlock falseArm = traverseBlock(falseTarget);
popScope();
return(new IfBlock(block, invert, trueArm, falseArm, joinArm));
}
private ControlBlock traverseLoop(NodeBlock block)
{
DNode last = block.nodes.last;
NodeBlock effectiveHeader = block;
LogicChain chain = null;
if (last.type == NodeType.JumpCondition)
{
DJumpCondition jcc = (DJumpCondition)last;
if (HasSharedTarget(block, jcc))
{
chain = buildLogicChain(block, null, out effectiveHeader);
}
}
last = effectiveHeader.nodes.last;
//Debug.Assert(last.type == NodeType.JumpCondition);
if (last.type == NodeType.JumpCondition)
{
// Assert that the backedge is a straight jump.
//Debug.Assert(BlockAnalysis.GetSingleTarget(graph_[block.lir.backedge.id]) == block);
NodeBlock join, body, cond;
ControlType type = findLoopJoinAndBody(block, effectiveHeader, out join, out body, out cond);
ControlBlock joinArm = traverseBlock(join);
ControlBlock bodyArm = null;
if (body != null)
{
pushScope(block);
pushScope(cond);
bodyArm = traverseBlockNoLoop(body);
popScope();
popScope();
}
if (chain != null)
{
return(new WhileLoop(type, chain, bodyArm, joinArm));
}
return(new WhileLoop(type, cond, bodyArm, joinArm));
}
return(null);
}
private NodeBlock findJoinOfSimpleIf(NodeBlock block, DJumpCondition jcc)
{
//Debug.Assert(block.nodes.last == jcc);
//Debug.Assert(block.lir.idominated[0] == jcc.falseTarget.lir || block.lir.idominated[0] == jcc.trueTarget.lir);
//Debug.Assert(block.lir.idominated[1] == jcc.falseTarget.lir || block.lir.idominated[1] == jcc.trueTarget.lir);
if (block.lir.idominated.Length == 2)
{
if (jcc.trueTarget != BlockAnalysis.EffectiveTarget(jcc.trueTarget))
{
return(jcc.trueTarget);
}
if (jcc.falseTarget != BlockAnalysis.EffectiveTarget(jcc.falseTarget))
{
return(jcc.falseTarget);
}
return(null);
}
return(graph_[block.lir.idominated[2].id]);
}
private static LogicOperator ToLogicOp(DJumpCondition jcc)
{
NodeBlock trueTarget = BlockAnalysis.EffectiveTarget(jcc.trueTarget);
bool targetIsTruthy = false;
if (trueTarget.lir.instructions[0] is LConstant)
{
LConstant constant = (LConstant)trueTarget.lir.instructions[0];
targetIsTruthy = (constant.val == 1);
}
// jump on true -> 1 == ||
// jump on false -> 0 == &&
// other combinations are nonsense, so assert.
////Debug.Assert((jcc.spop == SPOpcode.jnz && targetIsTruthy) ||
// (jcc.spop == SPOpcode.jzer && !targetIsTruthy));
LogicOperator logicop = (jcc.spop == SPOpcode.jnz && targetIsTruthy)
? LogicOperator.Or
: LogicOperator.And;
return(logicop);
}
public override void visit(DJumpCondition jcc)
{
jcc.typeSet.addType(new TypeUnit(new PawnType(CellType.Bool)));
}
public override void visit(DJumpCondition jcc)
{
if (jcc.getOperand(0).type == NodeType.Binary)
{
DBinary binary = (DBinary)jcc.getOperand(0);
propagateInputs(binary.lhs, binary.rhs);
}
}
private IfBlock traverseIf(NodeBlock block, DJumpCondition jcc)
{
if (HasSharedTarget(block, jcc))
return traverseComplexIf(block, jcc);
NodeBlock trueTarget = (jcc.spop == SPOpcode.jzer) ? jcc.falseTarget : jcc.trueTarget;
NodeBlock falseTarget = (jcc.spop == SPOpcode.jzer) ? jcc.trueTarget : jcc.falseTarget;
NodeBlock joinTarget = findJoinOfSimpleIf(block, jcc);
// If there is no join block (both arms terminate control flow),
// eliminate one arm and use the other as a join point.
if (joinTarget == null)
joinTarget = falseTarget;
// If the false target is equivalent to the join point, eliminate
// it.
if (BlockAnalysis.EffectiveTarget(falseTarget) == joinTarget)
falseTarget = null;
// If the true target is equivalent to the join point, promote
// the false target to the true target and undo the inversion.
bool invert = false;
if (BlockAnalysis.EffectiveTarget(trueTarget) == joinTarget)
{
trueTarget = falseTarget;
falseTarget = null;
invert ^= true;
}
// If there is always a true target and a join target.
pushScope(joinTarget);
ControlBlock trueArm = traverseBlock(trueTarget);
popScope();
ControlBlock joinArm = traverseJoin(joinTarget);
if (falseTarget == null)
return new IfBlock(block, invert, trueArm, joinArm);
pushScope(joinTarget);
ControlBlock falseArm = traverseBlock(falseTarget);
popScope();
return new IfBlock(block, invert, trueArm, falseArm, joinArm);
}
private IfBlock traverseComplexIf(NodeBlock block, DJumpCondition jcc)
{
// Degenerate case: using || or &&, or any combination thereof,
// will generate a chain of n+1 conditional blocks, where each
// |n| has a target to a shared "success" block, setting a
// phony variable. We decompose this giant mess into the intended
// sequence of expressions.
NodeBlock join;
LogicChain chain = buildLogicChain(block, null, out join);
DJumpCondition finalJcc = (DJumpCondition)join.nodes.last;
//Debug.Assert(finalJcc.spop == SPOpcode.jzer);
// The final conditional should have the normal dominator
// properties: 2 or 3 idoms, depending on the number of arms.
// Because of critical edge splitting, we may have 3 idoms
// even if there are only actually two arms.
NodeBlock joinBlock = findJoinOfSimpleIf(join, finalJcc);
// If an AND chain reaches its end, the result is 1. jzer tests
// for zero, so this is effectively testing (!success).
// If an OR expression reaches its end, the result is 0. jzer
// tests for zero, so this is effectively testing if (failure).
//
// In both cases, the true target represents a failure, so flip
// the targets around.
NodeBlock trueBlock = finalJcc.falseTarget;
NodeBlock falseBlock = finalJcc.trueTarget;
// If there is no join block, both arms terminate control flow,
// eliminate one arm and use the other as a join point.
if (joinBlock == null)
joinBlock = falseBlock;
if (join.lir.idominated.Length == 2 ||
BlockAnalysis.EffectiveTarget(falseBlock) == joinBlock)
{
if (join.lir.idominated.Length == 3)
joinBlock = BlockAnalysis.EffectiveTarget(falseBlock);
// One-armed structure.
pushScope(joinBlock);
ControlBlock trueArm1 = traverseBlock(trueBlock);
popScope();
ControlBlock joinArm1 = traverseBlock(joinBlock);
return new IfBlock(block, chain, trueArm1, joinArm1);
}
//Debug.Assert(join.lir.idominated.Length == 3);
pushScope(joinBlock);
ControlBlock trueArm2 = traverseBlock(trueBlock);
ControlBlock falseArm = traverseBlock(falseBlock);
popScope();
ControlBlock joinArm2 = traverseBlock(joinBlock);
return new IfBlock(block, chain, trueArm2, falseArm, joinArm2);
}
private NodeBlock findJoinOfSimpleIf(NodeBlock block, DJumpCondition jcc)
{
//Debug.Assert(block.nodes.last == jcc);
//Debug.Assert(block.lir.idominated[0] == jcc.falseTarget.lir || block.lir.idominated[0] == jcc.trueTarget.lir);
//Debug.Assert(block.lir.idominated[1] == jcc.falseTarget.lir || block.lir.idominated[1] == jcc.trueTarget.lir);
if (block.lir.idominated.Length == 2)
{
if (jcc.trueTarget != BlockAnalysis.EffectiveTarget(jcc.trueTarget))
return jcc.trueTarget;
if (jcc.falseTarget != BlockAnalysis.EffectiveTarget(jcc.falseTarget))
return jcc.falseTarget;
return null;
}
return graph_[block.lir.idominated[2].id];
}
private static LogicOperator ToLogicOp(DJumpCondition jcc)
{
NodeBlock trueTarget = BlockAnalysis.EffectiveTarget(jcc.trueTarget);
bool targetIsTruthy = false;
if (trueTarget.lir.instructions[0] is LConstant)
{
LConstant constant = (LConstant)trueTarget.lir.instructions[0];
targetIsTruthy = (constant.val == 1);
}
// jump on true -> 1 == ||
// jump on false -> 0 == &&
// other combinations are nonsense, so assert.
////Debug.Assert((jcc.spop == SPOpcode.jnz && targetIsTruthy) ||
// (jcc.spop == SPOpcode.jzer && !targetIsTruthy));
LogicOperator logicop = (jcc.spop == SPOpcode.jnz && targetIsTruthy)
? LogicOperator.Or
: LogicOperator.And;
return logicop;
}
private static bool HasSharedTarget(NodeBlock pred, DJumpCondition jcc)
{
NodeBlock trueTarget = BlockAnalysis.EffectiveTarget(jcc.trueTarget);
if (trueTarget.lir.numPredecessors == 1)
return false;
if (pred.lir.idominated.Length > 3)
return true;
// Hack... sniff out the case we care about, the true target
// probably having a conditional.
if (trueTarget.lir.instructions.Length == 2 &&
trueTarget.lir.instructions[0].op == Opcode.Constant &&
trueTarget.lir.instructions[1].op == Opcode.Jump)
{
return true;
}
// Because of edge splitting, there will always be at least 4
// dominators for the immediate dominator of a shared block.
return false;
}
public override void visit(DJumpCondition jcc)
{
}
public virtual void visit(DJumpCondition jcc)
{
}
public void traverse(NodeBlock block)
{
for (int i = 0; i < block.lir.numPredecessors; i++)
{
NodeBlock pred = blocks_[block.lir.getPredecessor(i).id];
// Don't bother with backedges yet.
if (pred.lir.id >= block.lir.id)
continue;
block.inherit(graph_, pred);
}
foreach (LInstruction uins in block.lir.instructions)
{
// Attempt to find static declarations. This is really
// expensive - we could cheapen it by creating per-method
// lists of statics.
{
int i = -1;
do
{
Variable var = file_.lookupDeclarations(uins.pc, ref i, Scope.Static);
if (var == null)
break;
block.add(new DDeclareStatic(var));
} while (true);
}
switch (uins.op)
{
case Opcode.DebugBreak:
break;
case Opcode.Stack:
{
LStack ins = (LStack)uins;
if (ins.amount < 0)
{
for (int i = 0; i < -ins.amount / 4; i++)
{
DDeclareLocal local = new DDeclareLocal(ins.pc, null);
block.stack.push(local);
block.add(local);
}
}
else
{
for (int i = 0; i < ins.amount / 4; i++)
block.stack.pop();
}
break;
}
case Opcode.Fill:
{
LFill ins = (LFill)uins;
DNode node = block.stack.alt;
DDeclareLocal local = (DDeclareLocal)node;
//Debug.Assert(block.stack.pri.type == NodeType.Constant);
for (int i = 0; i < ins.amount; i += 4)
block.stack.set(local.offset + i, block.stack.pri);
break;
}
case Opcode.Constant:
{
LConstant ins = (LConstant)uins;
DConstant v = new DConstant(ins.val, ins.pc);
block.stack.set(ins.reg, v);
block.add(v);
break;
}
case Opcode.PushConstant:
{
LPushConstant ins = (LPushConstant)uins;
DConstant v = new DConstant(ins.val);
DDeclareLocal local = new DDeclareLocal(ins.pc, v);
block.stack.push(local);
block.add(v);
block.add(local);
break;
}
case Opcode.PushReg:
{
LPushReg ins = (LPushReg)uins;
DDeclareLocal local = new DDeclareLocal(ins.pc, block.stack.reg(ins.reg));
block.stack.push(local);
block.add(local);
break;
}
case Opcode.Pop:
{
LPop ins = (LPop)uins;
DNode node = block.stack.popAsTemp();
block.stack.set(ins.reg, node);
break;
}
case Opcode.StackAddress:
{
LStackAddress ins = (LStackAddress)uins;
DDeclareLocal local = block.stack.getName(ins.offset);
block.stack.set(ins.reg, local);
break;
}
case Opcode.PushStackAddress:
{
LPushStackAddress ins = (LPushStackAddress)uins;
DLocalRef lref = new DLocalRef(block.stack.getName(ins.offset));
DDeclareLocal local = new DDeclareLocal(ins.pc, lref);
block.stack.push(local);
block.add(lref);
block.add(local);
break;
}
case Opcode.Goto:
{
LGoto ins = (LGoto)uins;
DJump node = new DJump(blocks_[ins.target.id]);
block.add(node);
break;
}
case Opcode.Jump:
{
LJump ins = (LJump)uins;
DJump node = new DJump(blocks_[ins.target.id]);
block.add(node);
break;
}
case Opcode.JumpCondition:
{
LJumpCondition ins = (LJumpCondition)uins;
NodeBlock lhtarget = blocks_[ins.trueTarget.id];
NodeBlock rhtarget = blocks_[ins.falseTarget.id];
DNode cmp = block.stack.pri;
SPOpcode jmp = ins.spop;
if (jmp != SPOpcode.jzer && jmp != SPOpcode.jnz)
{
SPOpcode newop;
switch (ins.spop)
{
case SPOpcode.jeq:
newop = SPOpcode.neq;
jmp = SPOpcode.jzer;
break;
case SPOpcode.jneq:
newop = SPOpcode.eq;
jmp = SPOpcode.jzer;
break;
case SPOpcode.jsgeq:
newop = SPOpcode.sless;
jmp = SPOpcode.jzer;
break;
case SPOpcode.jsgrtr:
newop = SPOpcode.sleq;
jmp = SPOpcode.jzer;
break;
case SPOpcode.jsleq:
newop = SPOpcode.sgrtr;
jmp = SPOpcode.jzer;
break;
case SPOpcode.jsless:
newop = SPOpcode.sgeq;
jmp = SPOpcode.jzer;
break;
default:
//Debug.Assert(false);
return;
}
cmp = new DBinary(newop, block.stack.pri, block.stack.alt);
block.add(cmp);
}
DJumpCondition jcc = new DJumpCondition(jmp, cmp, lhtarget, rhtarget);
block.add(jcc);
break;
}
case Opcode.LoadLocal:
{
LLoadLocal ins = (LLoadLocal)uins;
DLoad load = new DLoad(block.stack.getName(ins.offset));
block.stack.set(ins.reg, load);
block.add(load);
break;
}
case Opcode.LoadLocalRef:
{
LLoadLocalRef ins = (LLoadLocalRef)uins;
DLoad load = new DLoad(block.stack.getName(ins.offset));
load = new DLoad(load);
block.stack.set(ins.reg, load);
block.add(load);
break;
}
case Opcode.StoreLocal:
{
LStoreLocal ins = (LStoreLocal)uins;
DStore store = new DStore(block.stack.getName(ins.offset), block.stack.reg(ins.reg));
block.add(store);
break;
}
case Opcode.StoreLocalRef:
{
LStoreLocalRef ins = (LStoreLocalRef)uins;
DLoad load = new DLoad(block.stack.getName(ins.offset));
DStore store = new DStore(load, block.stack.reg(ins.reg));
block.add(store);
break;
}
case Opcode.SysReq:
{
LSysReq sysreq = (LSysReq)uins;
DConstant ins = (DConstant)block.stack.popValue();
List<DNode> arguments = new List<DNode>();
for (int i = 0; i < ins.value; i++)
arguments.Add(block.stack.popName());
DSysReq call = new DSysReq(sysreq.native, arguments.ToArray());
block.stack.set(Register.Pri, call);
block.add(call);
break;
}
case Opcode.AddConstant:
{
LAddConstant ins = (LAddConstant)uins;
DConstant val = new DConstant(ins.amount);
DBinary node = new DBinary(SPOpcode.add, block.stack.pri, val);
block.stack.set(Register.Pri, node);
block.add(val);
block.add(node);
break;
}
case Opcode.MulConstant:
{
LMulConstant ins = (LMulConstant)uins;
DConstant val = new DConstant(ins.amount);
DBinary node = new DBinary(SPOpcode.smul, block.stack.pri, val);
block.stack.set(Register.Pri, node);
block.add(val);
block.add(node);
break;
}
case Opcode.Bounds:
{
LBounds ins = (LBounds)uins;
DBoundsCheck node = new DBoundsCheck(block.stack.pri);
block.add(node);
break;
}
case Opcode.IndexAddress:
{
LIndexAddress ins = (LIndexAddress)uins;
DArrayRef node = new DArrayRef(block.stack.alt, block.stack.pri, ins.shift);
block.stack.set(Register.Pri, node);
block.add(node);
break;
}
case Opcode.Move:
{
LMove ins = (LMove)uins;
if (ins.reg == Register.Pri)
block.stack.set(Register.Pri, block.stack.alt);
else
block.stack.set(Register.Alt, block.stack.pri);
break;
}
case Opcode.Store:
{
LStore ins = (LStore)uins;
DStore store = new DStore(block.stack.alt, block.stack.pri);
block.add(store);
break;
}
case Opcode.Load:
{
LLoad ins = (LLoad)uins;
DLoad load = new DLoad(block.stack.pri);
block.stack.set(Register.Pri, load);
block.add(load);
break;
}
case Opcode.Swap:
{
LSwap ins = (LSwap)uins;
DNode lhs = block.stack.popAsTemp();
DNode rhs = block.stack.reg(ins.reg);
DDeclareLocal local = new DDeclareLocal(ins.pc, rhs);
block.stack.set(ins.reg, lhs);
block.stack.push(local);
block.add(local);
break;
}
case Opcode.IncI:
{
DIncDec inc = new DIncDec(block.stack.pri, 1);
block.add(inc);
break;
}
case Opcode.DecI:
{
DIncDec dec = new DIncDec(block.stack.pri, -1);
block.add(dec);
break;
}
case Opcode.IncLocal:
{
LIncLocal ins = (LIncLocal)uins;
DDeclareLocal local = block.stack.getName(ins.offset);
DIncDec inc = new DIncDec(local, 1);
block.add(inc);
break;
}
case Opcode.IncReg:
{
LIncReg ins = (LIncReg)uins;
DIncDec dec = new DIncDec(block.stack.reg(ins.reg), 1);
block.add(dec);
break;
}
case Opcode.DecLocal:
{
LDecLocal ins = (LDecLocal)uins;
DDeclareLocal local = block.stack.getName(ins.offset);
DIncDec dec = new DIncDec(local, -1);
block.add(dec);
break;
}
case Opcode.DecReg:
{
LDecReg ins = (LDecReg)uins;
DIncDec dec = new DIncDec(block.stack.reg(ins.reg), -1);
block.add(dec);
break;
}
case Opcode.Return:
{
DReturn node = new DReturn(block.stack.pri);
block.add(node);
break;
}
case Opcode.PushLocal:
{
LPushLocal ins = (LPushLocal)uins;
DLoad load = new DLoad(block.stack.getName(ins.offset));
DDeclareLocal local = new DDeclareLocal(ins.pc, load);
block.stack.push(local);
block.add(load);
block.add(local);
break;
}
case Opcode.Exchange:
{
DNode node = block.stack.alt;
block.stack.set(Register.Alt, block.stack.pri);
block.stack.set(Register.Pri, node);
break;
}
case Opcode.Unary:
{
LUnary ins = (LUnary)uins;
DUnary unary = new DUnary(ins.spop, block.stack.reg(ins.reg));
block.stack.set(Register.Pri, unary);
block.add(unary);
break;
}
case Opcode.Binary:
{
LBinary ins = (LBinary)uins;
DBinary binary = new DBinary(ins.spop, block.stack.reg(ins.lhs), block.stack.reg(ins.rhs));
block.stack.set(Register.Pri, binary);
block.add(binary);
break;
}
case Opcode.PushGlobal:
{
LPushGlobal ins = (LPushGlobal)uins;
Variable global = file_.lookupGlobal(ins.address);
if (global == null)
global = file_.lookupVariable(ins.pc, ins.address, Scope.Static);
DGlobal dglobal = new DGlobal(global);
DNode node = new DLoad(dglobal);
DDeclareLocal local = new DDeclareLocal(ins.pc, node);
block.stack.push(local);
block.add(dglobal);
block.add(node);
block.add(local);
break;
}
case Opcode.LoadGlobal:
{
LLoadGlobal ins = (LLoadGlobal)uins;
Variable global = file_.lookupGlobal(ins.address);
if (global == null)
global = file_.lookupVariable(ins.pc, ins.address, Scope.Static);
DNode dglobal = new DGlobal(global);
DNode node = new DLoad(dglobal);
block.stack.set(ins.reg, node);
block.add(dglobal);
block.add(node);
break;
}
case Opcode.StoreGlobal:
{
LStoreGlobal ins = (LStoreGlobal)uins;
Variable global = file_.lookupGlobal(ins.address);
if (global == null)
global = file_.lookupVariable(ins.pc, ins.address, Scope.Static);
DGlobal node = new DGlobal(global);
DStore store = new DStore(node, block.stack.reg(ins.reg));
block.add(node);
block.add(store);
break;
}
case Opcode.Call:
{
LCall ins = (LCall)uins;
Function f = file_.lookupFunction((uint)ins.address);
DConstant args = (DConstant)block.stack.popValue();
List<DNode> arguments = new List<DNode>();
for (int i = 0; i < args.value; i++)
arguments.Add(block.stack.popName());
DCall call = new DCall(f, arguments.ToArray());
block.stack.set(Register.Pri, call);
block.add(call);
break;
}
case Opcode.EqualConstant:
{
LEqualConstant ins = (LEqualConstant)uins;
DConstant c = new DConstant(ins.value);
DBinary node = new DBinary(SPOpcode.eq, block.stack.reg(ins.reg), c);
block.stack.set(Register.Pri, node);
block.add(c);
block.add(node);
break;
}
case Opcode.LoadIndex:
{
LLoadIndex ins = (LLoadIndex)uins;
DArrayRef aref = new DArrayRef(block.stack.alt, block.stack.pri, ins.shift);
DLoad load = new DLoad(aref);
block.stack.set(Register.Pri, load);
block.add(aref);
block.add(load);
break;
}
case Opcode.ZeroGlobal:
{
LZeroGlobal ins = (LZeroGlobal)uins;
Variable global = file_.lookupGlobal(ins.address);
DNode dglobal = new DGlobal(global);
DConstant rhs = new DConstant(0);
DStore lhs = new DStore(dglobal, rhs);
block.add(dglobal);
block.add(rhs);
block.add(lhs);
break;
}
case Opcode.IncGlobal:
{
LIncGlobal ins = (LIncGlobal)uins;
Variable global = file_.lookupGlobal(ins.address);
DNode dglobal = new DGlobal(global);
DLoad load = new DLoad(dglobal);
DConstant val = new DConstant(1);
DBinary add = new DBinary(SPOpcode.add, load, val);
DStore store = new DStore(dglobal, add);
block.add(load);
block.add(val);
block.add(add);
block.add(store);
break;
}
case Opcode.StoreGlobalConstant:
{
LStoreGlobalConstant lstore = (LStoreGlobalConstant)uins;
Variable var = file_.lookupGlobal(lstore.address);
DConstant val = new DConstant(lstore.value);
DGlobal global = new DGlobal(var);
DStore store = new DStore(global, val);
block.add(val);
block.add(global);
block.add(store);
break;
}
case Opcode.StoreLocalConstant:
{
LStoreLocalConstant lstore = (LStoreLocalConstant)uins;
DDeclareLocal var = block.stack.getName(lstore.address);
DConstant val = new DConstant(lstore.value);
DStore store = new DStore(var, val);
block.add(val);
block.add(store);
break;
}
case Opcode.ZeroLocal:
{
LZeroLocal lstore = (LZeroLocal)uins;
DDeclareLocal var = block.stack.getName(lstore.address);
DConstant val = new DConstant(0);
DStore store = new DStore(var, val);
block.add(val);
block.add(store);
break;
}
case Opcode.Heap:
{
LHeap ins = (LHeap)uins;
DHeap heap = new DHeap(ins.amount);
block.add(heap);
block.stack.set(Register.Alt, heap);
break;
}
case Opcode.MemCopy:
{
LMemCopy ins = (LMemCopy)uins;
DMemCopy copy = new DMemCopy(block.stack.alt, block.stack.pri, ins.bytes);
block.add(copy);
break;
}
case Opcode.Switch:
{
LSwitch ins = (LSwitch)uins;
DSwitch switch_ = new DSwitch(block.stack.pri, ins);
block.add(switch_);
break;
}
default:
throw new Exception("unhandled opcode");
}
}
for (int i = 0; i < block.lir.idominated.Length; i++)
{
LBlock lir = block.lir.idominated[i];
traverse(blocks_[lir.id]);
}
}
public override void visit(DJumpCondition jcc)
{
}
public void traverse(NodeBlock block)
{
for (int i = 0; i < block.lir.numPredecessors; i++)
{
NodeBlock pred = blocks_[block.lir.getPredecessor(i).id];
// Don't bother with backedges yet.
if (pred.lir.id >= block.lir.id)
{
continue;
}
block.inherit(graph_, pred);
}
foreach (LInstruction uins in block.lir.instructions)
{
// Attempt to find static declarations. This is really
// expensive - we could cheapen it by creating per-method
// lists of statics.
{
int i = -1;
do
{
Variable var = file_.lookupDeclarations(uins.pc, ref i, Scope.Static);
if (var == null)
{
break;
}
block.add(new DDeclareStatic(var));
} while (true);
}
switch (uins.op)
{
case Opcode.DebugBreak:
break;
case Opcode.Stack:
{
LStack ins = (LStack)uins;
if (ins.amount < 0)
{
for (int i = 0; i < -ins.amount / 4; i++)
{
DDeclareLocal local = new DDeclareLocal(ins.pc, null);
block.stack.push(local);
block.add(local);
}
}
else
{
for (int i = 0; i < ins.amount / 4; i++)
{
block.stack.pop();
}
}
break;
}
case Opcode.Fill:
{
LFill ins = (LFill)uins;
DNode node = block.stack.alt;
DDeclareLocal local = (DDeclareLocal)node;
//Debug.Assert(block.stack.pri.type == NodeType.Constant);
for (int i = 0; i < ins.amount; i += 4)
{
block.stack.set(local.offset + i, block.stack.pri);
}
break;
}
case Opcode.Constant:
{
LConstant ins = (LConstant)uins;
DConstant v = new DConstant(ins.val, ins.pc);
block.stack.set(ins.reg, v);
block.add(v);
break;
}
case Opcode.PushConstant:
{
LPushConstant ins = (LPushConstant)uins;
DConstant v = new DConstant(ins.val);
DDeclareLocal local = new DDeclareLocal(ins.pc, v);
block.stack.push(local);
block.add(v);
block.add(local);
break;
}
case Opcode.PushReg:
{
LPushReg ins = (LPushReg)uins;
DDeclareLocal local = new DDeclareLocal(ins.pc, block.stack.reg(ins.reg));
block.stack.push(local);
block.add(local);
break;
}
case Opcode.Pop:
{
LPop ins = (LPop)uins;
DNode node = block.stack.popAsTemp();
block.stack.set(ins.reg, node);
break;
}
case Opcode.StackAddress:
{
LStackAddress ins = (LStackAddress)uins;
DDeclareLocal local = block.stack.getName(ins.offset);
block.stack.set(ins.reg, local);
break;
}
case Opcode.PushStackAddress:
{
LPushStackAddress ins = (LPushStackAddress)uins;
DLocalRef lref = new DLocalRef(block.stack.getName(ins.offset));
DDeclareLocal local = new DDeclareLocal(ins.pc, lref);
block.stack.push(local);
block.add(lref);
block.add(local);
break;
}
case Opcode.Goto:
{
LGoto ins = (LGoto)uins;
DJump node = new DJump(blocks_[ins.target.id]);
block.add(node);
break;
}
case Opcode.Jump:
{
LJump ins = (LJump)uins;
DJump node = new DJump(blocks_[ins.target.id]);
block.add(node);
break;
}
case Opcode.JumpCondition:
{
LJumpCondition ins = (LJumpCondition)uins;
NodeBlock lhtarget = blocks_[ins.trueTarget.id];
NodeBlock rhtarget = blocks_[ins.falseTarget.id];
DNode cmp = block.stack.pri;
SPOpcode jmp = ins.spop;
if (jmp != SPOpcode.jzer && jmp != SPOpcode.jnz)
{
SPOpcode newop;
switch (ins.spop)
{
case SPOpcode.jeq:
newop = SPOpcode.neq;
jmp = SPOpcode.jzer;
break;
case SPOpcode.jneq:
newop = SPOpcode.eq;
jmp = SPOpcode.jzer;
break;
case SPOpcode.jsgeq:
newop = SPOpcode.sless;
jmp = SPOpcode.jzer;
break;
case SPOpcode.jsgrtr:
newop = SPOpcode.sleq;
jmp = SPOpcode.jzer;
break;
case SPOpcode.jsleq:
newop = SPOpcode.sgrtr;
jmp = SPOpcode.jzer;
break;
case SPOpcode.jsless:
newop = SPOpcode.sgeq;
jmp = SPOpcode.jzer;
break;
default:
//Debug.Assert(false);
return;
}
cmp = new DBinary(newop, block.stack.pri, block.stack.alt);
block.add(cmp);
}
DJumpCondition jcc = new DJumpCondition(jmp, cmp, lhtarget, rhtarget);
block.add(jcc);
break;
}
case Opcode.LoadLocal:
{
LLoadLocal ins = (LLoadLocal)uins;
DLoad load = new DLoad(block.stack.getName(ins.offset));
block.stack.set(ins.reg, load);
block.add(load);
break;
}
case Opcode.LoadLocalRef:
{
LLoadLocalRef ins = (LLoadLocalRef)uins;
DLoad load = new DLoad(block.stack.getName(ins.offset));
load = new DLoad(load);
block.stack.set(ins.reg, load);
block.add(load);
break;
}
case Opcode.StoreLocal:
{
LStoreLocal ins = (LStoreLocal)uins;
DStore store = new DStore(block.stack.getName(ins.offset), block.stack.reg(ins.reg));
block.add(store);
break;
}
case Opcode.StoreLocalRef:
{
LStoreLocalRef ins = (LStoreLocalRef)uins;
DLoad load = new DLoad(block.stack.getName(ins.offset));
DStore store = new DStore(load, block.stack.reg(ins.reg));
block.add(store);
break;
}
case Opcode.SysReq:
{
LSysReq sysreq = (LSysReq)uins;
DConstant ins = (DConstant)block.stack.popValue();
List <DNode> arguments = new List <DNode>();
for (int i = 0; i < ins.value; i++)
{
arguments.Add(block.stack.popName());
}
DSysReq call = new DSysReq(sysreq.native, arguments.ToArray());
block.stack.set(Register.Pri, call);
block.add(call);
break;
}
case Opcode.AddConstant:
{
LAddConstant ins = (LAddConstant)uins;
DConstant val = new DConstant(ins.amount);
DBinary node = new DBinary(SPOpcode.add, block.stack.pri, val);
block.stack.set(Register.Pri, node);
block.add(val);
block.add(node);
break;
}
case Opcode.MulConstant:
{
LMulConstant ins = (LMulConstant)uins;
DConstant val = new DConstant(ins.amount);
DBinary node = new DBinary(SPOpcode.smul, block.stack.pri, val);
block.stack.set(Register.Pri, node);
block.add(val);
block.add(node);
break;
}
case Opcode.Bounds:
{
LBounds ins = (LBounds)uins;
DBoundsCheck node = new DBoundsCheck(block.stack.pri);
block.add(node);
break;
}
case Opcode.IndexAddress:
{
LIndexAddress ins = (LIndexAddress)uins;
DArrayRef node = new DArrayRef(block.stack.alt, block.stack.pri, ins.shift);
block.stack.set(Register.Pri, node);
block.add(node);
break;
}
case Opcode.Move:
{
LMove ins = (LMove)uins;
if (ins.reg == Register.Pri)
{
block.stack.set(Register.Pri, block.stack.alt);
}
else
{
block.stack.set(Register.Alt, block.stack.pri);
}
break;
}
case Opcode.Store:
{
LStore ins = (LStore)uins;
DStore store = new DStore(block.stack.alt, block.stack.pri);
block.add(store);
break;
}
case Opcode.Load:
{
LLoad ins = (LLoad)uins;
DLoad load = new DLoad(block.stack.pri);
block.stack.set(Register.Pri, load);
block.add(load);
break;
}
case Opcode.Swap:
{
LSwap ins = (LSwap)uins;
DNode lhs = block.stack.popAsTemp();
DNode rhs = block.stack.reg(ins.reg);
DDeclareLocal local = new DDeclareLocal(ins.pc, rhs);
block.stack.set(ins.reg, lhs);
block.stack.push(local);
block.add(local);
break;
}
case Opcode.IncI:
{
DIncDec inc = new DIncDec(block.stack.pri, 1);
block.add(inc);
break;
}
case Opcode.DecI:
{
DIncDec dec = new DIncDec(block.stack.pri, -1);
block.add(dec);
break;
}
case Opcode.IncLocal:
{
LIncLocal ins = (LIncLocal)uins;
DDeclareLocal local = block.stack.getName(ins.offset);
DIncDec inc = new DIncDec(local, 1);
block.add(inc);
break;
}
case Opcode.IncReg:
{
LIncReg ins = (LIncReg)uins;
DIncDec dec = new DIncDec(block.stack.reg(ins.reg), 1);
block.add(dec);
break;
}
case Opcode.DecLocal:
{
LDecLocal ins = (LDecLocal)uins;
DDeclareLocal local = block.stack.getName(ins.offset);
DIncDec dec = new DIncDec(local, -1);
block.add(dec);
break;
}
case Opcode.DecReg:
{
LDecReg ins = (LDecReg)uins;
DIncDec dec = new DIncDec(block.stack.reg(ins.reg), -1);
block.add(dec);
break;
}
case Opcode.Return:
{
DReturn node = new DReturn(block.stack.pri);
block.add(node);
break;
}
case Opcode.PushLocal:
{
LPushLocal ins = (LPushLocal)uins;
DLoad load = new DLoad(block.stack.getName(ins.offset));
DDeclareLocal local = new DDeclareLocal(ins.pc, load);
block.stack.push(local);
block.add(load);
block.add(local);
break;
}
case Opcode.Exchange:
{
DNode node = block.stack.alt;
block.stack.set(Register.Alt, block.stack.pri);
block.stack.set(Register.Pri, node);
break;
}
case Opcode.Unary:
{
LUnary ins = (LUnary)uins;
DUnary unary = new DUnary(ins.spop, block.stack.reg(ins.reg));
block.stack.set(Register.Pri, unary);
block.add(unary);
break;
}
case Opcode.Binary:
{
LBinary ins = (LBinary)uins;
DBinary binary = new DBinary(ins.spop, block.stack.reg(ins.lhs), block.stack.reg(ins.rhs));
block.stack.set(Register.Pri, binary);
block.add(binary);
break;
}
case Opcode.PushGlobal:
{
LPushGlobal ins = (LPushGlobal)uins;
Variable global = file_.lookupGlobal(ins.address);
if (global == null)
{
global = file_.lookupVariable(ins.pc, ins.address, Scope.Static);
}
DGlobal dglobal = new DGlobal(global);
DNode node = new DLoad(dglobal);
DDeclareLocal local = new DDeclareLocal(ins.pc, node);
block.stack.push(local);
block.add(dglobal);
block.add(node);
block.add(local);
break;
}
case Opcode.LoadGlobal:
{
LLoadGlobal ins = (LLoadGlobal)uins;
Variable global = file_.lookupGlobal(ins.address);
if (global == null)
{
global = file_.lookupVariable(ins.pc, ins.address, Scope.Static);
}
DNode dglobal = new DGlobal(global);
DNode node = new DLoad(dglobal);
block.stack.set(ins.reg, node);
block.add(dglobal);
block.add(node);
break;
}
case Opcode.StoreGlobal:
{
LStoreGlobal ins = (LStoreGlobal)uins;
Variable global = file_.lookupGlobal(ins.address);
if (global == null)
{
global = file_.lookupVariable(ins.pc, ins.address, Scope.Static);
}
DGlobal node = new DGlobal(global);
DStore store = new DStore(node, block.stack.reg(ins.reg));
block.add(node);
block.add(store);
break;
}
case Opcode.Call:
{
LCall ins = (LCall)uins;
Function f = file_.lookupFunction((uint)ins.address);
DConstant args = (DConstant)block.stack.popValue();
List <DNode> arguments = new List <DNode>();
for (int i = 0; i < args.value; i++)
{
arguments.Add(block.stack.popName());
}
DCall call = new DCall(f, arguments.ToArray());
block.stack.set(Register.Pri, call);
block.add(call);
break;
}
case Opcode.EqualConstant:
{
LEqualConstant ins = (LEqualConstant)uins;
DConstant c = new DConstant(ins.value);
DBinary node = new DBinary(SPOpcode.eq, block.stack.reg(ins.reg), c);
block.stack.set(Register.Pri, node);
block.add(c);
block.add(node);
break;
}
case Opcode.LoadIndex:
{
LLoadIndex ins = (LLoadIndex)uins;
DArrayRef aref = new DArrayRef(block.stack.alt, block.stack.pri, ins.shift);
DLoad load = new DLoad(aref);
block.stack.set(Register.Pri, load);
block.add(aref);
block.add(load);
break;
}
case Opcode.ZeroGlobal:
{
LZeroGlobal ins = (LZeroGlobal)uins;
Variable global = file_.lookupGlobal(ins.address);
DNode dglobal = new DGlobal(global);
DConstant rhs = new DConstant(0);
DStore lhs = new DStore(dglobal, rhs);
block.add(dglobal);
block.add(rhs);
block.add(lhs);
break;
}
case Opcode.IncGlobal:
{
LIncGlobal ins = (LIncGlobal)uins;
Variable global = file_.lookupGlobal(ins.address);
DNode dglobal = new DGlobal(global);
DLoad load = new DLoad(dglobal);
DConstant val = new DConstant(1);
DBinary add = new DBinary(SPOpcode.add, load, val);
DStore store = new DStore(dglobal, add);
block.add(load);
block.add(val);
block.add(add);
block.add(store);
break;
}
case Opcode.StoreGlobalConstant:
{
LStoreGlobalConstant lstore = (LStoreGlobalConstant)uins;
Variable var = file_.lookupGlobal(lstore.address);
DConstant val = new DConstant(lstore.value);
DGlobal global = new DGlobal(var);
DStore store = new DStore(global, val);
block.add(val);
block.add(global);
block.add(store);
break;
}
case Opcode.StoreLocalConstant:
{
LStoreLocalConstant lstore = (LStoreLocalConstant)uins;
DDeclareLocal var = block.stack.getName(lstore.address);
DConstant val = new DConstant(lstore.value);
DStore store = new DStore(var, val);
block.add(val);
block.add(store);
break;
}
case Opcode.ZeroLocal:
{
LZeroLocal lstore = (LZeroLocal)uins;
DDeclareLocal var = block.stack.getName(lstore.address);
DConstant val = new DConstant(0);
DStore store = new DStore(var, val);
block.add(val);
block.add(store);
break;
}
case Opcode.Heap:
{
LHeap ins = (LHeap)uins;
DHeap heap = new DHeap(ins.amount);
block.add(heap);
block.stack.set(Register.Alt, heap);
break;
}
case Opcode.MemCopy:
{
LMemCopy ins = (LMemCopy)uins;
DMemCopy copy = new DMemCopy(block.stack.alt, block.stack.pri, ins.bytes);
block.add(copy);
break;
}
case Opcode.Switch:
{
LSwitch ins = (LSwitch)uins;
DSwitch switch_ = new DSwitch(block.stack.pri, ins);
block.add(switch_);
break;
}
default:
throw new Exception("unhandled opcode");
}
}
for (int i = 0; i < block.lir.idominated.Length; i++)
{
LBlock lir = block.lir.idominated[i];
traverse(blocks_[lir.id]);
}
}
private LogicChain buildLogicChain(NodeBlock block, NodeBlock earlyExitStop, out NodeBlock join)
{
DJumpCondition jcc = (DJumpCondition)block.nodes.last;
LogicChain chain = new LogicChain(ToLogicOp(jcc));
// Grab the true target, which will be either the "1" or "0"
// branch of the AND/OR expression.
NodeBlock earlyExit = BlockAnalysis.EffectiveTarget(jcc.trueTarget);
NodeBlock exprBlock = block;
do
{
do
{
DJumpCondition childJcc = (DJumpCondition)exprBlock.nodes.last;
if (BlockAnalysis.EffectiveTarget(childJcc.trueTarget) != earlyExit)
{
// Parse a sub-expression.
NodeBlock innerJoin;
LogicChain rhs = buildLogicChain(exprBlock, earlyExit, out innerJoin);
AssertInnerJoinValidity(innerJoin, earlyExit);
chain.append(rhs);
exprBlock = innerJoin;
childJcc = (DJumpCondition)exprBlock.nodes.last;
}
else
{
chain.append(childJcc.getOperand(0));
}
exprBlock = childJcc.falseTarget;
} while (exprBlock.nodes.last.type == NodeType.JumpCondition);
do
{
// We have reached the end of a sequence - a block containing
// a Constant and a Jump to the join point of the sequence.
//Debug.Assert(exprBlock.lir.instructions[0].op == Opcode.Constant);
// The next block is the join point.
NodeBlock condBlock = SingleTarget(exprBlock);
var last = condBlock.nodes.last;
DJumpCondition condJcc;
try
{
condJcc = (DJumpCondition)last;
}
catch (Exception e)
{
throw new LogicChainConversionException(e.Message);
}
join = condBlock;
// If the cond block is the tagret of the early stop, we've
// gone a tad too far. This is the case for a simple
// expression like (a && b) || c.
if (earlyExitStop != null && SingleTarget(earlyExitStop) == condBlock)
{
return(chain);
}
// If the true connects back to the early exit stop, we're
// done.
if (BlockAnalysis.EffectiveTarget(condJcc.trueTarget) == earlyExitStop)
{
return(chain);
}
// If the true target does not have a shared target, we're
// done parsing the whole logic chain.
if (!HasSharedTarget(condBlock, condJcc))
{
return(chain);
}
// Otherwise, there is another link in the chain. This link
// joins the existing chain to a new subexpression, which
// actually starts hanging off the false branch of this
// conditional.
earlyExit = BlockAnalysis.EffectiveTarget(condJcc.trueTarget);
// Build the right-hand side of the expression.
NodeBlock innerJoin;
LogicChain rhs = buildLogicChain(condJcc.falseTarget, earlyExit, out innerJoin);
AssertInnerJoinValidity(innerJoin, earlyExit);
// Build the full expression.
LogicChain root = new LogicChain(ToLogicOp(condJcc));
root.append(chain);
root.append(rhs);
chain = root;
// If the inner join's false target is a conditional, the
// outer expression may continue.
DJumpCondition innerJcc = (DJumpCondition)innerJoin.nodes.last;
if (innerJcc.falseTarget.nodes.last.type == NodeType.JumpCondition)
{
exprBlock = innerJcc.falseTarget;
break;
}
// Finally, the new expression block is always the early exit
// block. It's on the "trueTarget" edge of the expression,
// whereas incoming into this loop it's on the "falseTarget"
// edge, but this does not matter.
exprBlock = earlyExit;
} while (true);
} while (true);
}
private static void AssertInnerJoinValidity(NodeBlock join, NodeBlock earlyExit)
{
DJumpCondition jcc = (DJumpCondition)join.nodes.last;
//Debug.Assert(BlockAnalysis.EffectiveTarget(jcc.trueTarget) == earlyExit || join == SingleTarget(earlyExit));
}
public override void visit(DJumpCondition jcc)
{
jcc.typeSet.addType(new TypeUnit(new PawnType(CellType.Bool)));
}
private IfBlock traverseComplexIf(NodeBlock block, DJumpCondition jcc)
{
// Degenerate case: using || or &&, or any combination thereof,
// will generate a chain of n+1 conditional blocks, where each
// |n| has a target to a shared "success" block, setting a
// phony variable. We decompose this giant mess into the intended
// sequence of expressions.
NodeBlock join;
LogicChain chain = buildLogicChain(block, null, out join);
DJumpCondition finalJcc = (DJumpCondition)join.nodes.last;
//Debug.Assert(finalJcc.spop == SPOpcode.jzer);
// The final conditional should have the normal dominator
// properties: 2 or 3 idoms, depending on the number of arms.
// Because of critical edge splitting, we may have 3 idoms
// even if there are only actually two arms.
NodeBlock joinBlock = findJoinOfSimpleIf(join, finalJcc);
// If an AND chain reaches its end, the result is 1. jzer tests
// for zero, so this is effectively testing (!success).
// If an OR expression reaches its end, the result is 0. jzer
// tests for zero, so this is effectively testing if (failure).
//
// In both cases, the true target represents a failure, so flip
// the targets around.
NodeBlock trueBlock = finalJcc.falseTarget;
NodeBlock falseBlock = finalJcc.trueTarget;
// If there is no join block, both arms terminate control flow,
// eliminate one arm and use the other as a join point.
if (joinBlock == null)
{
joinBlock = falseBlock;
}
if (join.lir.idominated.Length == 2 ||
BlockAnalysis.EffectiveTarget(falseBlock) == joinBlock)
{
if (join.lir.idominated.Length == 3)
{
joinBlock = BlockAnalysis.EffectiveTarget(falseBlock);
}
// One-armed structure.
pushScope(joinBlock);
ControlBlock trueArm1 = traverseBlock(trueBlock);
popScope();
ControlBlock joinArm1 = traverseBlock(joinBlock);
return(new IfBlock(block, chain, trueArm1, joinArm1));
}
//Debug.Assert(join.lir.idominated.Length == 3);
pushScope(joinBlock);
ControlBlock trueArm2 = traverseBlock(trueBlock);
ControlBlock falseArm = traverseBlock(falseBlock);
popScope();
ControlBlock joinArm2 = traverseBlock(joinBlock);
return(new IfBlock(block, chain, trueArm2, falseArm, joinArm2));
}
public virtual void visit(DJumpCondition jcc) { }