santiagopg 2004/02/05 14:53:42
Modified: java/src/org/apache/xalan/xsltc/compiler FilterExpr.java
Predicate.java Step.java StepPattern.java
Log:
Patch for Bugzilla 19194. I've made the following changes: (i) re-wrote
Predicate.typeCheck() (ii) the predicate optimizations are turned off for
FilterExpr, as they don't apply in all cases (iii) sync up Step, StepPattern
and FilterExpr to accomodate the new changes. The interaction between these
classes is non-trivial, and the code for some optimizations is brittle, to say
the least. As part of this patch, I rolled back a patch to FilterExpr and fixed
Bugzilla 25783 which wasn't really related despite what the bug report states.
For the 2.0 work, it would be nice to place optimization code in separate
classes so that it can be easily maintained and also easily deactivated via a
command-line flag.
Revision Changes Path
1.10 +33 -39
xml-xalan/java/src/org/apache/xalan/xsltc/compiler/FilterExpr.java
Index: FilterExpr.java
===================================================================
RCS file:
/home/cvs/xml-xalan/java/src/org/apache/xalan/xsltc/compiler/FilterExpr.java,v
retrieving revision 1.9
retrieving revision 1.10
diff -u -r1.9 -r1.10
--- FilterExpr.java 19 Dec 2003 15:26:48 -0000 1.9
+++ FilterExpr.java 5 Feb 2004 22:53:42 -0000 1.10
@@ -80,7 +80,15 @@
import org.apache.xalan.xsltc.compiler.util.TypeCheckError;
class FilterExpr extends Expression {
+
+ /**
+ * Primary expression of this filter. I.e., 'e' in '(e)[p1]...[pn]'.
+ */
private Expression _primary;
+
+ /**
+ * Array of predicates in '(e)[p1]...[pn]'.
+ */
private final Vector _predicates;
public FilterExpr(Expression primary, Vector predicates) {
@@ -117,6 +125,8 @@
* Type check a FilterParentPath. If the filter is not a node-set add a
* cast to node-set only if it is of reference type. This type coercion
* is needed for expressions like $x where $x is a parameter reference.
+ * All optimizations are turned off before type checking underlying
+ * predicates.
*/
public Type typeCheck(SymbolTable stable) throws TypeCheckError {
Type ptype = _primary.typeCheck(stable);
@@ -130,9 +140,11 @@
}
}
+ // Type check predicates and turn all optimizations off
int n = _predicates.size();
for (int i = 0; i < n; i++) {
- Expression pred = (Expression)_predicates.elementAt(i);
+ Predicate pred = (Predicate) _predicates.elementAt(i);
+ pred.dontOptimize();
pred.typeCheck(stable);
}
return _type = Type.NodeSet;
@@ -148,26 +160,26 @@
}
else {
_primary.translate(classGen, methodGen);
- _primary.startIterator(classGen, methodGen);
}
}
/**
- * Translate a sequence of predicates.
- * Each predicate is translated by constructing an instance
- * of <code>CurrentNodeListIterator</code> which is initialized from
- * another iterator (recursive call), a filter and a closure
- * (call to translate on the predicate) and "this".
+ * Translate a sequence of predicates. Each predicate is translated
+ * by constructing an instance of <code>CurrentNodeListIterator</code>
+ * which is initialized from another iterator (recursive call), a
+ * filter and a closure (call to translate on the predicate) and "this".
*/
public void translatePredicates(ClassGenerator classGen,
MethodGenerator methodGen) {
final ConstantPoolGen cpg = classGen.getConstantPool();
final InstructionList il = methodGen.getInstructionList();
+ // If not predicates left, translate primary expression
if (_predicates.size() == 0) {
translate(classGen, methodGen);
}
else {
+ // Translate predicates from right to left
final int initCNLI = cpg.addMethodref(CURRENT_NODE_LIST_ITERATOR,
"<init>",
"("+NODE_ITERATOR_SIG+"Z"+
@@ -177,37 +189,19 @@
Predicate predicate = (Predicate)_predicates.lastElement();
_predicates.remove(predicate);
- if (predicate.isNthPositionFilter()) {
- final int start = cpg.addInterfaceMethodref(NODE_ITERATOR,
- "setStartNode",
- "(I)"+
- NODE_ITERATOR_SIG);
- final int reset = cpg.addInterfaceMethodref(NODE_ITERATOR,
- "reset",
- "()"+
- NODE_ITERATOR_SIG);
- translatePredicates(classGen, methodGen); // get the base itr.
- predicate.translate(classGen, methodGen); // get the position
- il.append(new INVOKEINTERFACE(start,2));
- il.append(new INVOKEINTERFACE(reset,1));
-
- final int sngl = cpg.addMethodref(BASIS_LIBRARY_CLASS,
- "getSingleNode",
- "("+NODE_ITERATOR_SIG+")"+
- NODE_ITERATOR_SIG);
- il.append(new INVOKESTATIC(sngl));
- }
- else {
- // create new CurrentNodeListIterator
- il.append(new NEW(cpg.addClass(CURRENT_NODE_LIST_ITERATOR)));
- il.append(DUP);
- translatePredicates(classGen, methodGen); // recursive call
- il.append(ICONST_1);
- predicate.translate(classGen, methodGen);
- il.append(methodGen.loadCurrentNode());
- il.append(classGen.loadTranslet());
- il.append(new INVOKESPECIAL(initCNLI));
- }
+ // Create a CurrentNodeListIterator
+ il.append(new NEW(cpg.addClass(CURRENT_NODE_LIST_ITERATOR)));
+ il.append(DUP);
+
+ // Translate the rest of the predicates from right to left
+ translatePredicates(classGen, methodGen);
+
+ // Initialize CurrentNodeListIterator
+ il.append(ICONST_1);
+ predicate.translate(classGen, methodGen);
+ il.append(methodGen.loadCurrentNode());
+ il.append(classGen.loadTranslet());
+ il.append(new INVOKESPECIAL(initCNLI));
}
}
}
1.31 +157 -122
xml-xalan/java/src/org/apache/xalan/xsltc/compiler/Predicate.java
Index: Predicate.java
===================================================================
RCS file:
/home/cvs/xml-xalan/java/src/org/apache/xalan/xsltc/compiler/Predicate.java,v
retrieving revision 1.30
retrieving revision 1.31
diff -u -r1.30 -r1.31
--- Predicate.java 15 Oct 2003 21:01:51 -0000 1.30
+++ Predicate.java 5 Feb 2004 22:53:42 -0000 1.31
@@ -92,36 +92,115 @@
final class Predicate extends Expression implements Closure {
- private Expression _exp = null; // Expression to be compiled inside pred.
+ /**
+ * The predicate's expression.
+ */
+ private Expression _exp = null;
+
+ /**
+ * This flag indicates if optimizations are turned on. The
+ * method <code>dontOptimize()</code> can be called to turn
+ * optimizations off.
+ */
+ private boolean _canOptimize = true;
+
+ /**
+ * Flag indicatig if the nth position optimization is on. It
+ * is set in <code>typeCheck()</code>.
+ */
private boolean _nthPositionFilter = false;
+
+ /**
+ * Flag indicatig if the nth position descendant is on. It
+ * is set in <code>typeCheck()</code>.
+ */
private boolean _nthDescendant = false;
- private boolean _canOptimize = true;
- private int _ptype = -1;
+ /**
+ * Cached node type of the expression that owns this predicate.
+ */
+ int _ptype = -1;
+
+ /**
+ * Name of the inner class.
+ */
private String _className = null;
+
+ /**
+ * List of variables in closure.
+ */
private ArrayList _closureVars = null;
+
+ /**
+ * Reference to parent closure.
+ */
private Closure _parentClosure = null;
+ /**
+ * Cached value of method <code>getCompareValue()</code>.
+ */
+ private Expression _value = null;
+
+ /**
+ * Cached value of method <code>getCompareValue()</code>.
+ */
+ private Step _step = null;
+
+ /**
+ * Initializes a predicate.
+ */
public Predicate(Expression exp) {
- (_exp = exp).setParent(this);
+ _exp = exp;
+ _exp.setParent(this);
+
}
+ /**
+ * Set the parser for this expression.
+ */
public void setParser(Parser parser) {
super.setParser(parser);
_exp.setParser(parser);
}
- public boolean isNthDescendant() {
- return _nthDescendant;
- }
-
+ /**
+ * Returns a boolean value indicating if the nth position optimization
+ * is on. Must be call after type checking!
+ */
public boolean isNthPositionFilter() {
return _nthPositionFilter;
}
+ /**
+ * Returns a boolean value indicating if the nth descendant optimization
+ * is on. Must be call after type checking!
+ */
+ public boolean isNthDescendant() {
+ return _nthDescendant;
+ }
+
+ /**
+ * Turns off all optimizations for this predicate.
+ */
public void dontOptimize() {
_canOptimize = false;
}
+
+ /**
+ * Returns true if the expression in this predicate contains a call
+ * to position().
+ */
+ public boolean hasPositionCall() {
+ return _exp.hasPositionCall();
+ }
+
+ /**
+ * Returns true if the expression in this predicate contains a call
+ * to last().
+ */
+ public boolean hasLastCall() {
+ return _exp.hasLastCall();
+ }
// -- Begin Closure interface --------------------
@@ -183,6 +262,10 @@
// -- End Closure interface ----------------------
+ /**
+ * Returns the node type of the expression owning this predicate. The
+ * return value is cached in <code>_ptype</code>.
+ */
public int getPosType() {
if (_ptype == -1) {
SyntaxTreeNode parent = getParent();
@@ -220,10 +303,7 @@
}
public String toString() {
- if (isNthPositionFilter())
- return "pred([" + _exp + "],"+getPosType()+")";
- else
- return "pred(" + _exp + ')';
+ return "pred(" + _exp + ')';
}
/**
@@ -232,9 +312,12 @@
* Note that if the expression is a parameter, we cannot distinguish
* at compile time if its type is number or not. Hence, expressions of
* reference type are always converted to booleans.
+ *
+ * This method may be called twice, before and after calling
+ * <code>dontOptimize()</code>. If so, the second time it should honor
+ * the new value of <code>_canOptimize</code>.
*/
- public Type typeCheck(SymbolTable stable) throws TypeCheckError {
-
+ public Type typeCheck(SymbolTable stable) throws TypeCheckError {
Type texp = _exp.typeCheck(stable);
// We need explicit type information for reference types - no good!
@@ -253,96 +336,50 @@
// Numerical types will be converted to a position filter
if (texp instanceof NumberType) {
-
// Cast any numerical types to an integer
if (texp instanceof IntType == false) {
_exp = new CastExpr(_exp, Type.Int);
}
-
- SyntaxTreeNode parent = getParent();
-
- // Expand [last()] into [position() = last()]
- if ((_exp instanceof LastCall) ||
- //Fix for bug 22949, check for last() for any expression
returns
- // NumberType
- _exp.hasLastCall()||
- (parent instanceof Pattern) ||
- (parent instanceof FilterExpr)) {
-
- if (parent instanceof Pattern && !(_exp instanceof LastCall)) {
- _nthPositionFilter = _canOptimize;
- }
- else if (parent instanceof FilterExpr) {
- FilterExpr filter = (FilterExpr)parent;
- Expression fexp = filter.getExpr();
-
- if (fexp instanceof KeyCall)
- _canOptimize = false;
- else if (fexp instanceof VariableRefBase)
- _canOptimize = false;
- else if (fexp instanceof ParentLocationPath)
- _canOptimize = false;
- else if (fexp instanceof FilterParentPath)
- _canOptimize = false;
- else if (fexp instanceof UnionPathExpr)
- _canOptimize = false;
- else if (_exp.hasPositionCall() && _exp.hasLastCall())
- _canOptimize = false;
- else if (filter.getParent() instanceof FilterParentPath)
- _canOptimize = false;
- if (_canOptimize)
- _nthPositionFilter = true;
- }
-
- // If this case can be optimized, leave the expression as
- // an integer. Otherwise, turn it into a comparison with
- // the position() function.
+
+ if (_canOptimize) {
+ // Nth position optimization. Expression must not depend on
context
+ _nthPositionFilter =
+ !_exp.hasLastCall() && !_exp.hasPositionCall();
+
+ // _nthDescendant optimization - only if _nthPositionFilter
is on
if (_nthPositionFilter) {
- return _type = Type.NodeSet;
- } else {
- final QName position =
-
getParser().getQNameIgnoreDefaultNs("position");
-
- final PositionCall positionCall =
- new PositionCall(position);
- positionCall.setParser(getParser());
- positionCall.setParent(this);
-
- _exp = new EqualityExpr(EqualityExpr.EQ, positionCall,
- _exp);
- if (_exp.typeCheck(stable) != Type.Boolean) {
- _exp = new CastExpr(_exp, Type.Boolean);
- }
-
- return _type = Type.Boolean;
+ SyntaxTreeNode parent = getParent();
+ _nthDescendant = (parent instanceof Step) &&
+ (parent.getParent() instanceof AbsoluteLocationPath);
+ return _type = Type.NodeSet;
}
- }
- // Use NthPositionIterator to handle [position()] or [a]
- else {
- if ((parent != null) && (parent instanceof Step)) {
- parent = parent.getParent();
- if ((parent != null) &&
- (parent instanceof AbsoluteLocationPath)) {
- // TODO: Special case for "//*[n]" pattern....
- _nthDescendant = true;
- return _type = Type.NodeSet;
- }
- }
- _nthPositionFilter = true;
- return _type = Type.NodeSet;
- }
- }
- else if (texp instanceof BooleanType) {
- if (_exp.hasPositionCall())
- _nthPositionFilter = true;
+ }
+
+ // Reset optimization flags
+ _nthPositionFilter = _nthDescendant = false;
+
+ // Otherwise, expand [e] to [position() = e]
+ final QName position =
+ getParser().getQNameIgnoreDefaultNs("position");
+ final PositionCall positionCall =
+ new PositionCall(position);
+ positionCall.setParser(getParser());
+ positionCall.setParent(this);
+
+ _exp = new EqualityExpr(EqualityExpr.EQ, positionCall,
+ _exp);
+ if (_exp.typeCheck(stable) != Type.Boolean) {
+ _exp = new CastExpr(_exp, Type.Boolean);
+ }
+ return _type = Type.Boolean;
}
- // All other types will be handled as boolean values
else {
- _exp = new CastExpr(_exp, Type.Boolean);
+ // All other types will be handled as boolean values
+ if (texp instanceof BooleanType == false) {
+ _exp = new CastExpr(_exp, Type.Boolean);
+ }
+ return _type = Type.Boolean;
}
- _nthPositionFilter = false;
-
- return _type = Type.Boolean;
}
/**
@@ -447,9 +484,6 @@
return (getStep() != null && getCompareValue() != null);
}
- private Expression _value = null;
- private Step _step = null;
-
/**
* Utility method for optimisation. See isNodeValueTest()
*/
@@ -517,29 +551,6 @@
* two references on the stack: a reference to a newly created
* filter object and a reference to the predicate's closure.
*/
- public void translate(ClassGenerator classGen, MethodGenerator
methodGen) {
-
- final ConstantPoolGen cpg = classGen.getConstantPool();
- final InstructionList il = methodGen.getInstructionList();
-
- if (_nthPositionFilter || _nthDescendant) {
- _exp.translate(classGen, methodGen);
- }
- else if (isNodeValueTest() && (getParent() instanceof Step)) {
- _value.translate(classGen, methodGen);
- il.append(new CHECKCAST(cpg.addClass(STRING_CLASS)));
- il.append(new PUSH(cpg, ((EqualityExpr)_exp).getOp()));
- }
- else {
- translateFilter(classGen, methodGen);
- }
- }
-
- /**
- * Translate a predicate expression. This translation pushes
- * two references on the stack: a reference to a newly created
- * filter object and a reference to the predicate's closure.
- */
public void translateFilter(ClassGenerator classGen,
MethodGenerator methodGen)
{
@@ -588,6 +599,30 @@
il.append(new PUTFIELD(
cpg.addFieldref(_className, var.getVariable(),
varType.toSignature())));
+ }
+ }
+
+ /**
+ * Translate a predicate expression. If non of the optimizations apply
+ * then this translation pushes two references on the stack: a reference
+ * to a newly created filter object and a reference to the predicate's
+ * closure. See class <code>Step</code> for further details.
+ */
+ public void translate(ClassGenerator classGen, MethodGenerator
methodGen) {
+
+ final ConstantPoolGen cpg = classGen.getConstantPool();
+ final InstructionList il = methodGen.getInstructionList();
+
+ if (_nthPositionFilter || _nthDescendant) {
+ _exp.translate(classGen, methodGen);
+ }
+ else if (isNodeValueTest() && (getParent() instanceof Step)) {
+ _value.translate(classGen, methodGen);
+ il.append(new CHECKCAST(cpg.addClass(STRING_CLASS)));
+ il.append(new PUSH(cpg, ((EqualityExpr)_exp).getOp()));
+ }
+ else {
+ translateFilter(classGen, methodGen);
}
}
}
1.44 +4 -3
xml-xalan/java/src/org/apache/xalan/xsltc/compiler/Step.java
Index: Step.java
===================================================================
RCS file:
/home/cvs/xml-xalan/java/src/org/apache/xalan/xsltc/compiler/Step.java,v
retrieving revision 1.43
retrieving revision 1.44
diff -u -r1.43 -r1.44
--- Step.java 1 Apr 2003 21:09:00 -0000 1.43
+++ Step.java 5 Feb 2004 22:53:42 -0000 1.44
@@ -417,11 +417,12 @@
GET_NODE_VALUE_ITERATOR,
GET_NODE_VALUE_ITERATOR_SIG);
il.append(new INVOKEINTERFACE(idx, 5));
- }
+ }
// Handle '//*[n]' expression
else if (predicate.isNthDescendant()) {
il.append(methodGen.loadDOM());
- il.append(new ICONST(NodeTest.ELEMENT));
+ // il.append(new ICONST(NodeTest.ELEMENT));
+ il.append(new ICONST(predicate.getPosType()));
predicate.translate(classGen, methodGen);
il.append(new ICONST(0));
idx = cpg.addInterfaceMethodref(DOM_INTF,
1.23 +7 -4
xml-xalan/java/src/org/apache/xalan/xsltc/compiler/StepPattern.java
Index: StepPattern.java
===================================================================
RCS file:
/home/cvs/xml-xalan/java/src/org/apache/xalan/xsltc/compiler/StepPattern.java,v
retrieving revision 1.22
retrieving revision 1.23
diff -u -r1.22 -r1.23
--- StepPattern.java 1 Apr 2003 21:09:00 -0000 1.22
+++ StepPattern.java 5 Feb 2004 22:53:42 -0000 1.23
@@ -202,9 +202,11 @@
final int n = _predicates.size();
for (int i = 0; i < n && noContext; i++) {
- final Predicate pred = (Predicate)_predicates.elementAt(i);
- if (pred.getExpr().hasPositionCall()
- || pred.isNthPositionFilter()) {
+ Predicate pred = (Predicate) _predicates.elementAt(i);
+ if (pred.isNthPositionFilter() ||
+ pred.hasPositionCall() ||
+ pred.hasLastCall())
+ {
noContext = false;
}
}
@@ -253,6 +255,7 @@
step = new Step(_axis, _nodeType, _predicates);
}
+
if (step != null) {
step.setParser(getParser());
step.typeCheck(stable);
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