private static void DoBinarySearch(MethodJumpEmittingContext context, int l, int r)
{
var il = context.il;
if (l > r)
{
il.Br(context.retNullLabel);
return;
}
if (r - l + 1 <= 3)
{
// just bunch of ifs
for (; l <= r; l++)
{
il.Ldarg(1); // stack: [key]
il.Ldarg(0); // stack: [key, this]
il.Ldfld(context.context.keys[l]); // stack: [key, this.keys[l]]
var nextLabel = il.DefineLabel("next");
il.Bne_Un(nextLabel); // if(key != this.keys[l]) goto next; stack: []
il.Ldarg(0); // stack: [this]
il.Ldfld(context.context.values[l]); // stack: [this.values[l]]
il.Ret();
il.MarkLabel(nextLabel);
}
il.Br(context.retNullLabel);
}
else
{
int m = (l + r) / 2;
il.Ldarg(1); // stack: [key]
il.Ldarg(0); // stack: [key, this]
il.Ldfld(context.context.keys[m]); // stack: [key, this.keys[m]]
var nextLabel = il.DefineLabel("next");
il.Bne_Un(nextLabel); // if(key != this.keys[m]) goto next; stack: []
il.Ldarg(0); // stack: [this]
il.Ldfld(context.context.values[m]); // stack: [this.values[m]]
il.Ret();
il.MarkLabel(nextLabel);
il.Ldarg(1); // stack: [key]
il.Ldarg(0); // stack: [key, this]
il.Ldfld(context.context.keys[m]); // stack: [key, this.keys[m]]
var goLeftLabel = il.DefineLabel("goLeft");
il.Blt(goLeftLabel, false); // if(key < this.keys[m]]) goto goLeft; stack: []
DoBinarySearch(context, m + 1, r);
il.MarkLabel(goLeftLabel);
DoBinarySearch(context, l, m - 1);
}
}
private static void BuildJump(TypeBuilder typeBuilder, int n, Context context)
{
var method = typeBuilder.DefineMethod("Jump", MethodAttributes.Public | MethodAttributes.Virtual, CallingConventions.HasThis, typeof(MethodCallNode), new[] { typeof(int) });
using (var il = new GroboIL(method))
{
var retNullLabel = il.DefineLabel("retNull");
var emittingContext = new MethodJumpEmittingContext
{
context = context,
il = il,
retNullLabel = retNullLabel
};
DoBinarySearch(emittingContext, 0, n - 1);
il.MarkLabel(retNullLabel);
il.Ldnull();
il.Ret();
}
typeBuilder.DefineMethodOverride(method, typeof(MethodCallNodeEdges).GetMethod(method.Name, BindingFlags.Public | BindingFlags.Instance));
}
