internal static void LoadFrameOrClearStack(JavaStackMap stackMap,
Mono.Cecil.Cil.Instruction inst)
{
// following any instruction that breaks the normal flow of execution,
// we need to load an stack frame already recorded for some following
// instruction, if any (e.g. as part of a conditional branch sequence).
// if there isn't such a frame, just clear and reset the stack frame.
for (;;)
{
inst = inst.Next;
if (inst == null)
{
break;
}
if (stackMap.LoadFrame((ushort)inst.Offset, true, null))
{
return;
}
var flowControl = inst.OpCode.FlowControl;
if (flowControl == Mono.Cecil.Cil.FlowControl.Branch ||
flowControl == Mono.Cecil.Cil.FlowControl.Break ||
flowControl == Mono.Cecil.Cil.FlowControl.Cond_Branch ||
flowControl == Mono.Cecil.Cil.FlowControl.Return ||
flowControl == Mono.Cecil.Cil.FlowControl.Throw)
{
break;
}
}
stackMap.ClearStack();
}
void ExceptionClauseSetup(ushort instOffset, CatchClause catchClause)
{
// if this is the first exception for the try block:
//
// the offset is recorded in the exception attribute, so we need
// to generate a stack frame for it, which matches the stack frame
// on entry to the try block, with a pushed java.lang.Throwable.
var tryClause = catchClause.tryClause;
if (catchClause == tryClause.catchClauses[0])
{
stackMap.LoadFrame((ushort)tryClause.tryStart, false, CilMain.Where);
stackMap.PushStack(ThrowableType);
stackMap.SaveFrame((ushort)instOffset, true, CilMain.Where);
if (!catchClause.finallyClause)
{
code.NewInstruction(0xB8 /* invokestatic */, CilType.SystemUtilType,
new JavaMethodRef("TranslateException",
ThrowableType, ThrowableType));
}
}
// if this is a finally clause, we have nothing further to do.
// but if this is a filter clause, do some additional set up.
if (catchClause.finallyClause)
{
if (catchClause.hasNestedTry)
{
// see also: ScanCatchClauseForNestedTry
SaveExceptionObject(tryClause, false);
}
if (catchClause.faultClause)
{
// the 'fault' clause should start with a check whether
// an exception was thrown, which is very similar to what
// 'endfinally' does at the end of a normal 'finally' block,
// so we can reuse the same code.
Translate_Endfinally(instOffset, true);
}
return;
}
//
// if this is a filter clause, we just need to initialize loals
//
if (catchClause.filterCondStart != 0)
{
// should the filter test pass, we need push the exception
// object. we don't know which local the filter test uses
// to store the exception, so we make our own copy. this
// will be loaded by the 'endfilter' instruction, see there.
SaveExceptionObject(tryClause);
return;
}
//
// for a non-filter catch clause that catches any kind of
// exception, we don't need to test the exception type at all
//
if (catchClause.catchType.Equals(ThrowableType))
{
if (catchClause.includesRethrow)
{
SaveExceptionObject(tryClause);
}
}
//
// otherwise, we do need to test the exception type, and
// possibly branch to a secondary catch clause in the chain.
//
if (catchClause.catchFromType == null)
{
// exception type is plain type. we will use follow up
// instructions 'ifeq == zero' and 'ifne != zero',
// see ExceptionClauseCommon
if (catchClause.catchType.Equals(ThrowableType))
{
code.NewInstruction(0x04 /* iconst_1 */, null, null);
stackMap.PushStack(JavaType.IntegerType);
}
else
{
code.NewInstruction(0x59 /* dup */, null, null);
stackMap.PushStack(ThrowableType);
code.NewInstruction(0xC1 /* instanceof */, catchClause.catchType, null);
}
}
else
{
// exception type is a generic type. we will use follow up
// instructions 'ifnull' and 'ifnonnnull'.
// see also below in ExceptionClauseCommon
code.NewInstruction(0x59 /* dup */, null, null);
stackMap.PushStack(ThrowableType);
GenericUtil.CastToGenericType(catchClause.catchFromType, 0, code);
}
stackMap.PopStack(CilMain.Where);
ExceptionClauseCommon(catchClause);
}
