// Returns true if the label was successfully defined
// or false if the label is now ambiguous
internal void Define(ILGen il, LabelBlockInfo block) {
// Prevent the label from being shadowed, which enforces cleaner
// trees. Also we depend on this for simplicity (keeping only one
// active IL Label per LabelInfo)
for (LabelBlockInfo j = block; j != null; j = j.Parent) {
if (j.ContainsTarget(Node)) {
throw Error.LabelTargetAlreadyDefined(Node.Name);
}
}
Definitions.Add(block);
block.AddLabelInfo(Node, this);
// Once defined, validate all jumps
if (Definitions.Count == 1) {
foreach (var r in References) {
ValidateJump(r);
}
} else {
// Was just redefined, if we had any across block jumps, they're
// now invalid
if (_acrossBlockJump) {
throw Error.AmbiguousJump(Node.Name);
}
// For local jumps, we need a new IL label
// This is okay because:
// 1. no across block jumps have been made or will be made
// 2. we don't allow the label to be shadowed
Label = il.DefineLabel();
}
}
internal void Reference(LabelBlockInfo block)
{
References.Add(block);
if (Definitions.Count > 0)
{
ValidateJump(block);
}
}
private void CheckRethrow()
{
// Rethrow is only valid inside a catch.
for (LabelBlockInfo j = _labelBlock; j != null; j = j.Parent)
{
if (j.Kind == LabelBlockKind.Catch)
{
return;
}
else if (j.Kind == LabelBlockKind.Finally)
{
// Rethrow from inside finally is not verifiable
break;
}
}
throw Error.RethrowRequiresCatch();
}
// Returns true if the label was successfully defined
// or false if the label is now ambiguous
internal void Define(ILGen il, LabelBlockInfo block)
{
// Prevent the label from being shadowed, which enforces cleaner
// trees. Also we depend on this for simplicity (keeping only one
// active IL Label per LabelInfo)
for (LabelBlockInfo j = block; j != null; j = j.Parent)
{
if (j.ContainsTarget(Node))
{
throw Error.LabelTargetAlreadyDefined(Node.Name);
}
}
Definitions.Add(block);
block.AddLabelInfo(Node, this);
// Once defined, validate all jumps
if (Definitions.Count == 1)
{
foreach (var r in References)
{
ValidateJump(r);
}
}
else
{
// Was just redefined, if we had any across block jumps, they're
// now invalid
if (_acrossBlockJump)
{
throw Error.AmbiguousJump(Node.Name);
}
// For local jumps, we need a new IL label
// This is okay because:
// 1. no across block jumps have been made or will be made
// 2. we don't allow the label to be shadowed
Label = il.DefineLabel();
}
}
private void PushLabelBlock(LabelBlockKind type) {
_labelBlock = new LabelBlockInfo(_labelBlock, type);
}
internal void Reference(LabelBlockInfo block) {
References.Add(block);
if (Definitions.Count > 0) {
ValidateJump(block);
}
}
internal LabelBlockInfo(LabelBlockInfo parent, LabelBlockKind kind) {
Parent = parent;
Kind = kind;
}
private void ValidateJump(LabelBlockInfo reference) {
// Assume we can do a ret/branch
_opCode = _canReturn ? OpCodes.Ret : OpCodes.Br;
// look for a simple jump out
for (LabelBlockInfo j = reference; j != null; j = j.Parent) {
if (Definitions.Contains(j)) {
// found it, jump is valid!
return;
}
if (j.Kind == LabelBlockKind.Finally ||
j.Kind == LabelBlockKind.Filter) {
break;
}
if (j.Kind == LabelBlockKind.Try ||
j.Kind == LabelBlockKind.Catch) {
_opCode = OpCodes.Leave;
}
}
_acrossBlockJump = true;
if (Definitions.Count > 1) {
throw Error.AmbiguousJump(Node.Name);
}
// We didn't find an outward jump. Look for a jump across blocks
LabelBlockInfo def = Definitions.First();
LabelBlockInfo common = Helpers.CommonNode(def, reference, b => b.Parent);
// Assume we can do a ret/branch
_opCode = _canReturn ? OpCodes.Ret : OpCodes.Br;
// Validate that we aren't jumping across a finally
for (LabelBlockInfo j = reference; j != common; j = j.Parent) {
if (j.Kind == LabelBlockKind.Finally) {
throw Error.ControlCannotLeaveFinally();
}
if (j.Kind == LabelBlockKind.Filter) {
throw Error.ControlCannotLeaveFilterTest();
}
if (j.Kind == LabelBlockKind.Try ||
j.Kind == LabelBlockKind.Catch) {
_opCode = OpCodes.Leave;
}
}
// Valdiate that we aren't jumping into a catch or an expression
for (LabelBlockInfo j = def; j != common; j = j.Parent) {
if (j.Kind != LabelBlockKind.Block) {
if (j.Kind == LabelBlockKind.Expression) {
throw Error.ControlCannotEnterExpression();
} else {
throw Error.ControlCannotEnterTry();
}
}
}
}
private void PushLabelBlock(LabelBlockKind type)
{
_labelBlock = new LabelBlockInfo(_labelBlock, type);
}
internal LabelBlockInfo(LabelBlockInfo parent, LabelBlockKind kind)
{
Parent = parent;
Kind = kind;
}
private void ValidateJump(LabelBlockInfo reference)
{
// Assume we can do a ret/branch
_opCode = _canReturn ? OpCodes.Ret : OpCodes.Br;
// look for a simple jump out
for (LabelBlockInfo j = reference; j != null; j = j.Parent)
{
if (Definitions.Contains(j))
{
// found it, jump is valid!
return;
}
if (j.Kind == LabelBlockKind.Finally ||
j.Kind == LabelBlockKind.Filter)
{
break;
}
if (j.Kind == LabelBlockKind.Try ||
j.Kind == LabelBlockKind.Catch)
{
_opCode = OpCodes.Leave;
}
}
_acrossBlockJump = true;
if (Definitions.Count > 1)
{
throw Error.AmbiguousJump(Node.Name);
}
// We didn't find an outward jump. Look for a jump across blocks
LabelBlockInfo def = Definitions.First();
LabelBlockInfo common = Helpers.CommonNode(def, reference, b => b.Parent);
// Assume we can do a ret/branch
_opCode = _canReturn ? OpCodes.Ret : OpCodes.Br;
// Validate that we aren't jumping across a finally
for (LabelBlockInfo j = reference; j != common; j = j.Parent)
{
if (j.Kind == LabelBlockKind.Finally)
{
throw Error.ControlCannotLeaveFinally();
}
if (j.Kind == LabelBlockKind.Filter)
{
throw Error.ControlCannotLeaveFilterTest();
}
if (j.Kind == LabelBlockKind.Try ||
j.Kind == LabelBlockKind.Catch)
{
_opCode = OpCodes.Leave;
}
}
// Valdiate that we aren't jumping into a catch or an expression
for (LabelBlockInfo j = def; j != common; j = j.Parent)
{
if (j.Kind != LabelBlockKind.Block)
{
if (j.Kind == LabelBlockKind.Expression)
{
throw Error.ControlCannotEnterExpression();
}
else
{
throw Error.ControlCannotEnterTry();
}
}
}
}
