Refactor bytecode analysis

src/jse/org/luaj/vm2/luajc/UpvalInfo.java

@@ -0,0 +1,113 @@
+/**
+ * 
+ */
+package org.luaj.vm2.luajc;
+
+public class UpvalInfo {
+	ProtoInfo pi;    // where defined
+	int slot;       // where defined
+	int nvars;		// number of vars involved
+	VarInfo var[];	// list of vars
+	boolean rw;     // read-write
+	
+	public UpvalInfo(ProtoInfo pi, int pc, int slot) {
+		this.pi = pi;
+		this.slot = slot;
+		this.nvars = 0;
+		this.var = null;
+		includeVars( pi.vars[slot][pc] );
+		for ( int i=0; i<nvars; i++ )
+			var[i].allocupvalue = testIsAllocUpvalue( var[i] );
+		this.rw = nvars > 1;		
+	}
+
+	public String toString() {
+		StringBuffer sb = new StringBuffer();
+		sb.append( pi.name );
+		for ( int i=0; i<nvars; i++ ) {
+			sb.append( i>0? ",": " " );
+			sb.append( String.valueOf(var[i]));
+		}
+		if ( rw )
+			sb.append( "(rw)" );
+		return sb.toString();
+	}
+	
+	private void includeVar(VarInfo v) {
+		if ( v == null )
+			return;
+		if ( includes(v) )
+			return;
+		if ( nvars == 0 ) {
+			var = new VarInfo[1];
+		} else if ( nvars+1 >= var.length ) {
+			VarInfo[] s = var;
+			var = new VarInfo[nvars*2+1];
+			System.arraycopy(s, 0, var, 0, nvars);				
+		}
+		var[nvars++] = v;
+	}
+	
+	private boolean includes(VarInfo v) {
+		for ( int i=0; i<nvars; i++ )
+			if ( var[i] == v )
+				return true;
+		return false;
+	}
+	
+	public void includeVars(VarInfo v) {
+		int slot = this.slot;
+		
+		// check for previous assignment
+		loop: while ( true ) {
+			BasicBlock b = pi.blocks[v.pc];
+			if ( v.upvalue == this ) {
+				// loop detected, include previous values
+				for ( int i=0, n=b.ninputs[slot]; i<n; i++ ) {
+					v = b.inputs[slot][i];
+					if ( v.upvalue != this )
+						includeVars(v);
+				}
+				return;
+			}
+			
+			// check for assignment to 2 upvalues at once
+			if ( v.upvalue != null ) 
+				throw new IllegalArgumentException("upvalue collision detected between "+v.upvalue+" and "+this);
+
+			// invalid values terminate search
+			if ( v == VarInfo.INVALID )
+				return;
+			
+			// assign the variable
+			v.upvalue = this;
+			this.includeVar(v);
+
+			// find next variable within the basic block
+			for ( int i=v.pc; i<=b.pc1; i++ ) {
+				if ( pi.vars[slot][i] != v ) {
+					v = pi.vars[slot][i];
+					continue loop;
+				}
+			}
+			
+			// at end of basic block, go to next blocks
+			for ( int i=0, n=b.next!=null? b.next.length: 0; i<n; i++ )
+				includeVars(pi.vars[slot][b.next[i].pc0]);
+			return;
+		}
+	}
+	
+	private boolean testIsAllocUpvalue(VarInfo v) {
+		BasicBlock b = pi.blocks[v.pc];
+		if ( v.pc > b.pc0 )
+			return pi.vars[slot][v.pc-1].upvalue != this;
+		if ( b.ninputs[slot] <= 0 )
+			return true;
+		for ( int k=0, n=b.ninputs[slot]; k<n; k++ )
+			if ( b.inputs[slot][k].upvalue != this )
+				return true;
+		return false;
+	}
+
+}