/**
* Make a work function for a joiner
*
* @param joiner the InputSliceNode that we are generating code for.
* @param backEndBits way to refer to other portions of backend
* @param joiner_code place to put code
*/
public static void makeJoinerWork(
InputSliceNode joiner, BackEndFactory backEndBits, CodeStoreHelper joiner_code) {
JMethodDeclaration joinerWork;
// the work function will need a temporary variable
ALocalVariable t = ALocalVariable.makeTmp(joiner.getEdgeToNext().getType());
Channel downstream = backEndBits.getChannel(joiner.getEdgeToNext());
// the body of the work method
JBlock body = new JBlock();
if (backEndBits.sliceNeedsJoinerCode(joiner.getParent())) {
// There should be generated code for the joiner
// state machine in the CodeStoreHelper as the only method.
//
// generated code is
// T tmp;
// tmp = joiner_code();
// push(tmp);
//
// TODO: inline the joiner code at the call site,
// if inlining, delete joiner code after inlining leaving
// only this method in the helper.
assert joiner_code.getMethods().length == 1;
JMethodDeclaration callable_joiner = joiner_code.getMethods()[0];
body.addStatement(t.getDecl());
body.addStatement(
new JExpressionStatement(
new JAssignmentExpression(
t.getRef(),
new JMethodCallExpression(callable_joiner.getName(), new JExpression[0]))));
body.addStatement(
new JExpressionStatement(
new JMethodCallExpression(
downstream.pushMethodName(), new JExpression[] {t.getRef()})));
} else {
// slice does not need joiner code, so just transfer from upstream
// to downstream buffer.
//
// generated code is
// T tmp;
// tmp = pop();
// push(tmp);
//
assert joiner.getWidth() == 1;
Channel upstream = backEndBits.getChannel(joiner.getSingleEdge());
body.addStatement(t.getDecl());
body.addStatement(
new JExpressionStatement(
new JAssignmentExpression(
t.getRef(),
new JMethodCallExpression(upstream.popMethodName(), new JExpression[0]))));
body.addStatement(
new JExpressionStatement(
new JMethodCallExpression(
downstream.pushMethodName(), new JExpression[] {t.getRef()})));
}
joinerWork =
new JMethodDeclaration(
CStdType.Void,
"_joinerWork_" + joiner.getNextFilter().getFilter().getName(),
JFormalParameter.EMPTY,
body);
joiner_code.setWorkMethod(joinerWork);
joiner_code.addMethod(joinerWork);
}
/**
* Create fields and code for a joiner, as follows. Do not create a joiner if all weights are 0:
* this code fails rather than creating nonsensical kopi code. Note that this <b>always</b>
* creates code, if you want to reuse any existing code call {@link #getJoinerCode(InputSliceNode,
* BackEndFactory) getJoinerCode} instead.
*
* <pre>
* joiner as a state machine, driven off arrays:
*
* / * joiner (unless single edge, just delegated to a channel
* arity (4) and weight s but not duplication.
* /
*
* T pop_1_M() {fprintf(stderr, "pop_1_M\n"); return 0;}
* T pop_2_M() {fprintf(stderr, "pop_2_M\n"); return 0;}
* T pop_4_M() {fprintf(stderr, "pop_4_M\n"); return 0;}
*
*
* static int joiner_M_edge = 4 - 1;
* static int joiner_M_weight = 0;
*
* static inline T joiner_M() {
*
* / * attempt to place const either applies it to function, or gives parse error
* do we need to move this to file scope to convince inliner to work on joiner_M?
* /
* static T (*pops[4])() = {
* pop_1_M,
* pop_2_M,
* 0, / * 0-weight edge * /
* pop_4_M
* };
*
* static const int weights[4] = {2, 1, 0, 2};
*
* while (joiner_M_weight == 0) { / * "if" if do not generate for 0-length edges. * /
* joiner_M_edge = (joiner_M_edge + 1) % 4;
* joiner_M_weight = weights[joiner_M_edge];
* }
* joiner_M_weight--;
*
* return pops[joiner_M_edge]();
* }
*
* joiner as a case statement, which is what we implement:
*
*
* static int joiner_M_unrolled_edge = 3 - 1;
* static int joiner_M_unrolled_weight = 0;
*
* static inline T joiner_M_unrolled() {
*
* static const int weights[3] = {2-1, 1-1, 2-1};
*
* if (--joiner_M_unrolled_weight < 0) {
* joiner_M_unrolled_edge = (joiner_M_unrolled_edge + 1) % 3;
* joiner_M_unrolled_weight = weights[joiner_M_unrolled_edge];
* }
*
* switch (joiner_M_unrolled_edge) {
* case 0:
* return pop_1_M();
* case 1:
* return pop_2_M();
* case 2:
* return pop_4_M();
* }
* }
* </pre>
*
* @param joiner An InputSliceNode specifying joiner weights and edges.
* @param backEndBits to get info from appropriate BackEndFactory
* @param helper CodeStoreHelper to get the fields and method implementing the joiner
*/
private static void makeJoinerCode(
InputSliceNode joiner, BackEndFactory backEndBits, CodeStoreHelper helper) {
String joiner_name = "_joiner_" + ProcessFilterSliceNode.getUid();
String joiner_method_name = joiner_name + joiner.getNextFilter().getFilter().getName();
// size is number of edges with non-zero weight.
int size = 0;
for (int w : joiner.getWeights()) {
if (w != 0) {
size++;
}
}
assert size > 0 : "asking for code generation for null joiner";
String edge_name = joiner_name + "_edge";
String weight_name = joiner_name + "_weight";
JVariableDefinition edgeVar =
new JVariableDefinition(
at.dms.kjc.Constants.ACC_STATIC,
CStdType.Integer,
edge_name,
new JIntLiteral(size - 1));
JFieldDeclaration edgeDecl = new JFieldDeclaration(edgeVar);
JFieldAccessExpression edgeExpr = new JFieldAccessExpression(edge_name);
JVariableDefinition weightVar =
new JVariableDefinition(
at.dms.kjc.Constants.ACC_STATIC, CStdType.Integer, weight_name, new JIntLiteral(0));
JFieldDeclaration weightDecl = new JFieldDeclaration(weightVar);
JFieldAccessExpression weightExpr = new JFieldAccessExpression(weight_name);
JIntLiteral[] weightVals = new JIntLiteral[size];
{
int i = 0;
for (int w : joiner.getWeights()) {
if (w != 0) {
weightVals[i++] = new JIntLiteral(w - 1);
}
}
}
JVariableDefinition weightsArray =
new JVariableDefinition(
at.dms.kjc.Constants.ACC_STATIC | at.dms.kjc.Constants.ACC_FINAL, // static const in C
new CArrayType(CStdType.Integer, 1, new JExpression[] {new JIntLiteral(size)}),
"weights",
new JArrayInitializer(weightVals));
JLocalVariableExpression weightsExpr = new JLocalVariableExpression(weightsArray);
JStatement next_edge_weight_stmt =
new JIfStatement(
null,
new JRelationalExpression(
at.dms.kjc.Constants.OPE_LT,
new JPrefixExpression(null, at.dms.kjc.Constants.OPE_PREDEC, weightExpr),
new JIntLiteral(0)),
new JBlock(
new JStatement[] {
new JExpressionStatement(
new JAssignmentExpression(
edgeExpr,
new JModuloExpression(
null,
new JAddExpression(edgeExpr, new JIntLiteral(1)),
new JIntLiteral(size)))),
new JExpressionStatement(
new JAssignmentExpression(
weightExpr, new JArrayAccessExpression(weightsExpr, edgeExpr)))
}),
new JEmptyStatement(),
null);
JSwitchGroup[] cases = new JSwitchGroup[size]; // fill in later.
JStatement switch_on_edge_stmt = new JSwitchStatement(null, edgeExpr, cases, null);
{
int i = 0;
for (int j = 0; j < joiner.getWeights().length; j++) {
if (joiner.getWeights()[j] != 0) {
JMethodCallExpression pop =
new JMethodCallExpression(
backEndBits.getChannel(joiner.getSources()[j]).popMethodName(),
new JExpression[0]);
pop.setType(joiner.getType());
cases[i] =
new JSwitchGroup(
null,
new JSwitchLabel[] {new JSwitchLabel(null, new JIntLiteral(i))},
new JStatement[] {new JReturnStatement(null, pop, null)});
i++;
}
}
}
JMethodDeclaration joiner_method =
new JMethodDeclaration(
null,
at.dms.kjc.Constants.ACC_STATIC | at.dms.kjc.Constants.ACC_INLINE,
joiner.getType(),
joiner_method_name,
new JFormalParameter[] {},
new CClassType[] {},
new JBlock(),
null,
null);
JBlock joiner_block = joiner_method.getBody();
joiner_block.addStatement(
new JVariableDeclarationStatement(new JVariableDefinition[] {weightsArray}));
joiner_block.addStatement(next_edge_weight_stmt);
joiner_block.addStatement(switch_on_edge_stmt);
helper.addFields(new JFieldDeclaration[] {edgeDecl, weightDecl});
helper.addMethod(joiner_method);
}