org.jruby.ir.transformations.inlining.CFGInliner Maven / Gradle / Ivy
package org.jruby.ir.transformations.inlining;
import java.util.Set;
import java.util.List;
import java.util.ArrayList;
import java.util.HashSet;
import org.jruby.RubyModule;
import org.jruby.ir.IRClosure;
import org.jruby.ir.IRScope;
import org.jruby.ir.Tuple;
import org.jruby.ir.instructions.CallBase;
import org.jruby.ir.instructions.JumpInstr;
import org.jruby.ir.instructions.ModuleVersionGuardInstr;
import org.jruby.ir.instructions.ToAryInstr;
import org.jruby.ir.instructions.YieldInstr;
import org.jruby.ir.operands.Array;
import org.jruby.ir.operands.Label;
import org.jruby.ir.operands.Operand;
import org.jruby.ir.operands.Variable;
import org.jruby.ir.operands.WrappedIRClosure;
import org.jruby.ir.representations.BasicBlock;
import org.jruby.ir.representations.CFG;
import org.jruby.ir.representations.CFG.EdgeType;
import org.jruby.ir.representations.ExceptionRegion;
import org.jruby.ir.util.Edge;
public class CFGInliner {
private CFG cfg;
public CFGInliner(CFG build) {
this.cfg = build;
}
private CFG cloneSelf(InlinerInfo ii) {
CFG selfClone = new CFG(cfg.getScope());
// clone bbs
BasicBlock entry = cfg.getEntryBB();
BasicBlock exit = cfg.getExitBB();
for (BasicBlock b : cfg.getBasicBlocks()) {
if ((b != entry) && (b != exit)) {
selfClone.addBasicBlock(b.cloneForInlinedMethod(ii));
}
}
// clone edges
for (BasicBlock b: cfg.getBasicBlocks()) {
if ((b != entry) && (b != exit)) {
BasicBlock rb = ii.getRenamedBB(b);
for (Edge e : cfg.getOutgoingEdges(b)) {
BasicBlock destination = e.getDestination().getData();
if (destination != exit) selfClone.addEdge(rb, ii.getRenamedBB(destination), e.getType());
}
}
}
return selfClone;
}
public void inlineMethod(IRScope scope, RubyModule implClass, int classToken, BasicBlock callBB, CallBase call) {
// Temporarily turn off inlining of recursive methods
// Conservative turning off for inlining of a method in a closure nested within the same method
IRScope hostScope = cfg.getScope();
if (hostScope.getNearestMethod() == scope) return;
/*
System.out.println("host cfg :" + cfg.toStringGraph());
System.out.println("host instrs:" + cfg.toStringInstrs());
System.out.println("source cfg :" + scope.getCFG().toStringGraph());
System.out.println("source instrs:" + scope.getCFG().toStringInstrs());
*/
// Host method data init
InlinerInfo ii = new InlinerInfo(call, cfg);
Label splitBBLabel = hostScope.getNewLabel();
BasicBlock splitBB;
// Inlinee method data init
CFG methodCFG = scope.getCFG();
BasicBlock mEntry = methodCFG.getEntryBB();
BasicBlock mExit = methodCFG.getExitBB();
List methodBBs = new ArrayList();
for (BasicBlock b: methodCFG.getBasicBlocks()) methodBBs.add(b);
// Check if we are inlining a recursive method
if (hostScope.getNearestMethod() == scope) {
// 1. clone self
// SSS: FIXME: We need a clone-graph api method in cfg and graph
CFG selfClone = cloneSelf(ii);
// 2. add callee bbs and their edges
// SSS: FIXME: We need a swallow-graph api method in cfg and graph
for (BasicBlock b : selfClone.getBasicBlocks()) {
cfg.addBasicBlock(b);
for (Edge e : selfClone.getOutgoingEdges(b)) {
cfg.addEdge(b, e.getDestination().getData(), e.getType());
}
}
} else {
// 2. clone callee and add it to the host cfg
for (BasicBlock b : methodCFG.getBasicBlocks()) {
if (b != mEntry && b != mExit) {
cfg.addBasicBlock(b.cloneForInlinedMethod(ii));
}
}
for (BasicBlock x : methodCFG.getBasicBlocks()) {
if (x != mEntry && x != mExit) {
BasicBlock rx = ii.getRenamedBB(x);
for (Edge e : methodCFG.getOutgoingEdges(x)) {
BasicBlock b = e.getDestination().getData();
if (b != mExit) cfg.addEdge(rx, ii.getRenamedBB(b), e.getType());
}
}
}
}
// 3. split callsite bb, move outbound edges from callsite bb to split bb, and unhook call bb
splitBB = callBB.splitAtInstruction(call, splitBBLabel, false);
cfg.addBasicBlock(splitBB);
for (Edge e : cfg.getOutgoingEdges(callBB)) {
cfg.addEdge(splitBB, e.getDestination().getData(), e.getType());
}
cfg.removeAllOutgoingEdgesForBB(callBB);
// 4a. Hook up entry edges
assert methodCFG.outDegree(mEntry) == 2: "Entry BB of inlinee method does not have outdegree 2: " + methodCFG.toStringGraph();
for (Edge e : methodCFG.getOutgoingEdges(mEntry)) {
BasicBlock destination = e.getDestination().getData();
if (destination != mExit) {
BasicBlock dstBB = ii.getRenamedBB(destination);
if (!ii.canMapArgsStatically()) {
dstBB.addInstr(new ToAryInstr((Variable)ii.getArgs(), new Array(call.getCallArgs()), cfg.getScope().getManager().getTrue()));
}
cfg.addEdge(callBB, dstBB, CFG.EdgeType.FALL_THROUGH);
}
}
// 4b. Hook up exit edges
for (Edge e : methodCFG.getIncomingEdges(mExit)) {
BasicBlock source = e.getSource().getData();
if (source != mEntry) {
BasicBlock clonedSource = ii.getRenamedBB(source);
if (e.getType() == EdgeType.EXCEPTION) {
// e._src has an explicit throw that returns from the callee
// after inlining, if the caller instruction has a rescuer, then the
// throw has to be captured by the rescuer as well.
BasicBlock rescuerOfSplitBB = cfg.getRescuerBBFor(splitBB);
if (rescuerOfSplitBB != null) {
cfg.addEdge(clonedSource, rescuerOfSplitBB, EdgeType.EXCEPTION);
} else {
cfg.addEdge(clonedSource, cfg.getExitBB(), EdgeType.EXIT);
}
} else {
cfg.addEdge(clonedSource, splitBB, e.getType());
}
}
}
// SSS FIXME: Are these used anywhere post-CFG building?
// 5. Clone exception regions
List exceptionRegions = cfg.getOutermostExceptionRegions();
for (ExceptionRegion r : methodCFG.getOutermostExceptionRegions()) {
exceptionRegions.add(r.cloneForInlining(ii));
}
// 6. Update bb rescuer map
// 6a. splitBB will be protected by the same bb as callBB
BasicBlock callBBrescuer = cfg.getRescuerBBFor(callBB);
if (callBBrescuer != null) cfg.setRescuerBB(splitBB, callBBrescuer);
BasicBlock callBBensurer = cfg.getEnsurerBBFor(callBB);
if (callBBensurer != null) cfg.setEnsurerBB(splitBB, callBBensurer);
// 6b. remap existing protections for bbs in mcfg to their renamed bbs.
// 6c. bbs in mcfg that aren't protected by an existing bb will be protected by callBBrescuer.
for (BasicBlock x : methodBBs) {
if (x != mEntry && x != mExit) {
BasicBlock xRenamed = ii.getRenamedBB(x);
BasicBlock xProtector = methodCFG.getRescuerBBFor(x);
if (xProtector != null) {
cfg.setRescuerBB(xRenamed, ii.getRenamedBB(xProtector));
} else if (callBBrescuer != null) {
cfg.setRescuerBB(xRenamed, callBBrescuer);
}
BasicBlock xEnsurer = methodCFG.getEnsurerBBFor(x);
if (xEnsurer != null) {
cfg.setEnsurerBB(xRenamed, ii.getRenamedBB(xEnsurer));
} else if (callBBensurer != null) {
cfg.setEnsurerBB(xRenamed, callBBensurer);
}
}
}
// 7. Add inline guard that verifies that the method inlined is the same
// that gets called in future invocations. In addition to the guard, add
// a failure path code.
Label failurePathLabel = hostScope.getNewLabel();
callBB.addInstr(new ModuleVersionGuardInstr(implClass, classToken, call.getReceiver(), failurePathLabel));
BasicBlock failurePathBB = new BasicBlock(cfg, failurePathLabel);
cfg.addBasicBlock(failurePathBB);
failurePathBB.addInstr(call);
failurePathBB.addInstr(new JumpInstr(splitBBLabel));
call.blockInlining();
cfg.addEdge(callBB, failurePathBB, CFG.EdgeType.REGULAR);
cfg.addEdge(failurePathBB, splitBB, CFG.EdgeType.REGULAR);
// 8. Inline any closure argument passed into the call.
Operand closureArg = call.getClosureArg(null);
List yieldSites = ii.getYieldSites();
if (closureArg != null && !yieldSites.isEmpty()) {
// Detect unlikely but contrived scenarios where there are far too many yield sites that could lead to code blowup
// if we inline the closure at all those yield sites!
if (yieldSites.size() > 1) {
throw new RuntimeException("Encountered " + yieldSites.size() + " yield sites. Convert the yield to a call by converting the closure into a dummy method (have to convert all frame vars to call arguments, or at least convert the frame into a call arg");
}
if (!(closureArg instanceof WrappedIRClosure)) {
throw new RuntimeException("Encountered a dynamic closure arg. Cannot inline it here! Convert the yield to a call by converting the closure into a dummy method (have to convert all frame vars to call arguments, or at least convert the frame into a call arg");
}
Tuple t = (Tuple) yieldSites.get(0);
inlineClosureAtYieldSite(ii, ((WrappedIRClosure) closureArg).getClosure(), (BasicBlock) t.a, (YieldInstr) t.b);
}
// 9. Optimize cfg by merging straight-line bbs
cfg.collapseStraightLineBBs();
/*
System.out.println("final cfg :" + cfg.toStringGraph());
System.out.println("final instrs:" + cfg.toStringInstrs());
*/
}
private void inlineClosureAtYieldSite(InlinerInfo ii, IRClosure cl, BasicBlock yieldBB, YieldInstr yield) {
// 1. split yield site bb and move outbound edges from yield site bb to split bb.
BasicBlock splitBB = yieldBB.splitAtInstruction(yield, cfg.getScope().getNewLabel(), false);
cfg.addBasicBlock(splitBB);
for (Edge e : cfg.getOutgoingEdges(yieldBB)) {
cfg.addEdge(splitBB, e.getDestination().getData(), e.getType());
}
cfg.removeAllOutgoingEdgesForBB(yieldBB);
// Allocate new inliner object to reset variable and label rename maps
ii = ii.cloneForInliningClosure();
ii.setupYieldArgsAndYieldResult(yield, yieldBB, cl.getBlockBody().arity());
// 2. Merge closure cfg into the current cfg
CFG closureCFG = cl.getCFG();
BasicBlock cEntry = closureCFG.getEntryBB();
BasicBlock cExit = closureCFG.getExitBB();
for (BasicBlock b : closureCFG.getBasicBlocks()) {
if (b != cEntry && b != cExit) {
cfg.addBasicBlock(b.cloneForInlinedClosure(ii));
}
}
for (BasicBlock b : closureCFG.getBasicBlocks()) {
if (b != cEntry && b != cExit) {
BasicBlock bClone = ii.getRenamedBB(b);
for (Edge e : closureCFG.getOutgoingEdges(b)) {
BasicBlock edst = e.getDestination().getData();
if (edst != cExit) cfg.addEdge(bClone, ii.getRenamedBB(edst), e.getType());
}
}
}
// Hook up entry edges
for (Edge e : closureCFG.getOutgoingEdges(cEntry)) {
BasicBlock destination = e.getDestination().getData();
if (destination != cExit) {
cfg.addEdge(yieldBB, ii.getRenamedBB(destination), CFG.EdgeType.FALL_THROUGH);
}
}
// Hook up exit edges
for (Edge e : closureCFG.getIncomingEdges(cExit)) {
BasicBlock source = e.getSource().getData();
if (source != cEntry) {
BasicBlock clonedSource = ii.getRenamedBB(source);
if (e.getType() == EdgeType.EXCEPTION) {
// e._src has an explicit throw that returns from the closure.
// After inlining, if the yield instruction has a rescuer, then the
// throw has to be captured by the rescuer as well.
BasicBlock rescuerOfSplitBB = cfg.getRescuerBBFor(splitBB);
if (rescuerOfSplitBB != null) {
cfg.addEdge(clonedSource, rescuerOfSplitBB, EdgeType.EXCEPTION);
} else {
cfg.addEdge(clonedSource, cfg.getExitBB(), EdgeType.EXIT);
}
} else {
cfg.addEdge(clonedSource, splitBB, e.getType());
}
}
}
// SSS FIXME: Are these used anywhere post-CFG building?
// 5. No need to clone rescued regions -- just assimilate them
List exceptionRegions = cfg.getOutermostExceptionRegions();
for (ExceptionRegion r : closureCFG.getOutermostExceptionRegions()) {
exceptionRegions.add(r.cloneForInlining(ii));
}
// 6. Update bb rescuer map
// 6a. splitBB will be protected by the same bb as yieldB
BasicBlock yieldBBrescuer = cfg.getRescuerBBFor(yieldBB);
if (yieldBBrescuer != null) cfg.setRescuerBB(splitBB, yieldBBrescuer);
BasicBlock yieldBBensurer = cfg.getEnsurerBBFor(yieldBB);
if (yieldBBensurer != null) cfg.setEnsurerBB(splitBB, yieldBBensurer);
// 6b. remap existing protections for bbs in mcfg to their renamed bbs.
// 6c. bbs in mcfg that aren't protected by an existing bb will be protected by yieldBBrescuer/yieldBBensurer
for (BasicBlock cb : closureCFG.getBasicBlocks()) {
if (cb != cEntry && cb != cExit) {
BasicBlock cbProtector = ii.getRenamedBB(closureCFG.getRescuerBBFor(cb));
if (cbProtector != null) {
cfg.setRescuerBB(cb, cbProtector);
} else if (yieldBBrescuer != null) {
cfg.setRescuerBB(cb, yieldBBrescuer);
}
BasicBlock cbEnsurer = ii.getRenamedBB(closureCFG.getEnsurerBBFor(cb));
if (cbEnsurer != null) {
cfg.setEnsurerBB(cb, cbEnsurer);
} else if (yieldBBensurer != null) {
cfg.setEnsurerBB(cb, yieldBBensurer);
}
}
}
}
}
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