internal override void Generate(CodeGenerator cg)
{
// four cases:
// 1. just single or none case label that can be replaced with single IF
// 2. switch over integers, using native CIL switch
// 3. switch over strings, using C# static Dictionary and CIL switch
// 4. PHP style switch which is just a bunch of IFs
if (this.CaseBlocks.Length == 0 || this.CaseBlocks[0].IsDefault)
{
Debug.Assert(this.CaseBlocks.Length <= 1);
// no SWITCH or IF needed
cg.EmitPop(this.SwitchValue.WithAccess(BoundAccess.None).Emit(cg)); // None Access, also using BoundExpression.Emit directly to avoid CodeGenerator type specialization which is not needed
if (this.CaseBlocks.Length == 1)
{
cg.GenerateScope(this.CaseBlocks[0], NextBlock.Ordinal);
}
}
else
{
// CIL Switch:
bool allconsts = this.CaseBlocks.All(c => c.IsDefault || c.CaseValue.ConstantObject.HasValue);
bool allconstints = allconsts && this.CaseBlocks.All(c => c.IsDefault || IsInt32(c.CaseValue.ConstantObject.Value));
//bool allconststrings = allconsts && this.CaseBlocks.All(c => c.IsDefault || IsString(c.CaseValue.ConstantValue.Value));
var default_block = this.DefaultBlock;
// <switch_loc> = <SwitchValue>;
TypeSymbol switch_type;
LocalDefinition switch_loc;
// Switch Header
if (allconstints)
{
switch_type = cg.CoreTypes.Int32;
cg.EmitSequencePoint(this.SwitchValue.PhpSyntax);
cg.EmitConvert(this.SwitchValue, switch_type);
switch_loc = cg.GetTemporaryLocal(switch_type);
cg.Builder.EmitLocalStore(switch_loc);
// switch (labels)
cg.Builder.EmitIntegerSwitchJumpTable(GetSwitchCaseLabels(CaseBlocks), default_block ?? NextBlock, switch_loc, switch_type.PrimitiveTypeCode);
}
//else if (allconststrings)
//{
//}
else
{
// legacy jump table
// IF (case_i) GOTO label_i;
cg.EmitSequencePoint(this.SwitchValue.PhpSyntax);
switch_type = cg.Emit(this.SwitchValue);
switch_loc = cg.GetTemporaryLocal(switch_type);
cg.Builder.EmitLocalStore(switch_loc);
//
for (int i = 0; i < this.CaseBlocks.Length; i++)
{
var this_block = this.CaseBlocks[i];
if (this_block.CaseValue != null)
{
// <CaseValue>:
cg.EmitSequencePoint(this_block.CaseValue.PhpSyntax);
// if (<switch_loc> == c.CaseValue) goto this_block;
cg.Builder.EmitLocalLoad(switch_loc);
BoundBinaryEx.EmitEquality(cg, switch_type, this_block.CaseValue);
cg.Builder.EmitBranch(ILOpCode.Brtrue, this_block);
}
}
// default:
cg.Builder.EmitBranch(ILOpCode.Br, default_block ?? NextBlock);
}
// FREE <switch_loc>
cg.ReturnTemporaryLocal(switch_loc);
// Switch Body
this.CaseBlocks.ForEach((i, this_block) =>
{
var next_case = (i + 1 < this.CaseBlocks.Length) ? this.CaseBlocks[i + 1] : null;
// {
cg.GenerateScope(this_block, (next_case ?? NextBlock).Ordinal);
// }
});
}
//
cg.Scope.ContinueWith(NextBlock);
}
internal override void Generate(CodeGenerator cg)
{
// four cases:
// 1. just single or none case label that can be replaced with single IF
// 2. switch over integers, using native CIL switch
// 3. switch over strings, using C# static Dictionary and CIL switch
// 4. PHP style switch which is just a bunch of IFs
if (this.CaseBlocks.Length == 0 || (this.CaseBlocks[0].IsDefault && this.CaseBlocks.Length == 1))
{
Debug.Assert(this.CaseBlocks.Length <= 1);
// no SWITCH or IF needed
cg.EmitPop(this.SwitchValue.WithAccess(BoundAccess.None).Emit(cg)); // None Access, also using BoundExpression.Emit directly to avoid CodeGenerator type specialization which is not needed
if (this.CaseBlocks.Length != 0)
{
cg.GenerateScope(this.CaseBlocks[0], NextBlock.Ordinal);
}
}
else
{
// CIL Switch:
bool allConst = this.CaseBlocks.All(c => c.IsDefault || (c.CaseValue.IsOnlyBoundElement && c.CaseValue.BoundElement.ConstantValue.HasValue));
bool allIntConst = allConst && this.CaseBlocks.All(c => c.IsDefault || IsInt32(c.CaseValue.BoundElement.ConstantValue.Value));
//bool allconststrings = allconsts && this.CaseBlocks.All(c => c.IsDefault || IsString(c.CaseValue.ConstantValue.Value));
var default_block = this.DefaultBlock;
// <switch_loc> = <SwitchValue>;
TypeSymbol switch_type;
LocalDefinition switch_loc;
// Switch Header
if (allIntConst)
{
switch_type = cg.CoreTypes.Int32;
cg.EmitSequencePoint(this.SwitchValue.PhpSyntax);
cg.EmitConvert(this.SwitchValue, switch_type);
switch_loc = cg.GetTemporaryLocal(switch_type);
cg.Builder.EmitLocalStore(switch_loc);
// switch (labels)
cg.Builder.EmitIntegerSwitchJumpTable(GetSwitchCaseLabels(CaseBlocks), default_block ?? NextBlock, switch_loc, switch_type.PrimitiveTypeCode);
}
//else if (allconststrings)
//{
//}
else
{
// legacy jump table
// IF (case_i) GOTO label_i;
cg.EmitSequencePoint(this.SwitchValue.PhpSyntax);
switch_type = cg.Emit(this.SwitchValue);
switch_loc = cg.GetTemporaryLocal(switch_type);
cg.Builder.EmitLocalStore(switch_loc);
//
foreach (var this_block in this.CaseBlocks)
{
var caseValueBag = this_block.CaseValue;
if (caseValueBag.IsEmpty)
{
continue;
}
if (!caseValueBag.IsOnlyBoundElement)
{
cg.ReturnTemporaryLocal(switch_loc); // statements in pre-bound-blocks could return (e.g. yieldStatement) & destroy stack-local switch_loc variable -> be defensive
caseValueBag.PreBoundBlockFirst.Emit(cg); // emit all blocks that have to go before case value emit
}
// reininiaze switch_loc if destroyed previously
if (!caseValueBag.IsOnlyBoundElement)
{
cg.Emit(this.SwitchValue);
switch_loc = cg.GetTemporaryLocal(switch_type);
cg.Builder.EmitLocalStore(switch_loc);
}
// <CaseValue>:
var caseValue = caseValueBag.BoundElement;
cg.EmitSequencePoint(caseValue.PhpSyntax);
// if (<switch_loc> == c.CaseValue) goto this_block;
cg.Builder.EmitLocalLoad(switch_loc);
BoundBinaryEx.EmitEquality(cg, switch_type, caseValue);
cg.Builder.EmitBranch(ILOpCode.Brtrue, this_block);
}
// default:
cg.Builder.EmitBranch(ILOpCode.Br, default_block ?? NextBlock);
}
// FREE <switch_loc>
cg.ReturnTemporaryLocal(switch_loc);
// Switch Body
this.CaseBlocks.ForEach((i, this_block) =>
{
var next_case = (i + 1 < this.CaseBlocks.Length) ? this.CaseBlocks[i + 1] : null;
// {
cg.GenerateScope(this_block, (next_case ?? NextBlock).Ordinal);
// }
});
}
cg.Scope.ContinueWith(NextBlock);
}