diff options
Diffstat (limited to 'chapter19/src')
3 files changed, 51 insertions, 4 deletions
diff --git a/chapter19/src/main/java/com/seaofnodes/simple/node/CFGNode.java b/chapter19/src/main/java/com/seaofnodes/simple/node/CFGNode.java index d57c3e8c..383f18d0 100644 --- a/chapter19/src/main/java/com/seaofnodes/simple/node/CFGNode.java +++ b/chapter19/src/main/java/com/seaofnodes/simple/node/CFGNode.java @@ -106,7 +106,7 @@ public abstract class CFGNode extends Node { // ------------------------------------------------------------------------ // Tag all CFG Nodes with their containing LoopNode; LoopNodes themselves // also refer to *their* containing LoopNode, as well as have their depth. - // Start is a LoopNode which contains all at depth 1. + // Start contains the function bodies at depth 0; real loops add depth. public void buildLoopTree(StopNode stop) { _ltree = stop._ltree = Parser.XCTRL._ltree = new LoopTree((StartNode)this); _bltWalk(2,null,stop, new BitSet()); @@ -115,6 +115,14 @@ public abstract class CFGNode extends Node { // Pre-walked? if( _pre!=0 ) return pre; _pre = pre++; + // Seed the function's outer tree before walking its body. Synthetic + // exits can be added before the post-order walk reaches the entry. + if( this instanceof FunNode ) _ltree = stop._ltree; + if( this instanceof ReturnNode ) { + _ltree = fun._ltree; + post.set(_nid); + return pre; // Stop/Start links describe the outside world, not a loop. + } // Pre-walk for( Node use : _outputs ) if( use instanceof CFGNode usecfg && !skip( usecfg ) ) diff --git a/chapter19/src/main/java/com/seaofnodes/simple/node/LoopNode.java b/chapter19/src/main/java/com/seaofnodes/simple/node/LoopNode.java index 5482a737..db353c1d 100644 --- a/chapter19/src/main/java/com/seaofnodes/simple/node/LoopNode.java +++ b/chapter19/src/main/java/com/seaofnodes/simple/node/LoopNode.java @@ -31,7 +31,7 @@ public class LoopNode extends RegionNode { // If this is an unreachable loop, it may not have an exit. If it does not // (i.e., infinite loop), force an exit to make it reachable. - public StopNode forceExit( FunNode fun, StopNode stop ) { + public FunNode forceExit( FunNode fun, StopNode stop ) { // Walk the backedge, then immediate dominator tree util we hit this // Loop again. If we ever hit a CProj from an If (as opposed to // directly on the If) we found our exit. @@ -40,7 +40,7 @@ public class LoopNode extends RegionNode { if( x instanceof CProjNode exit && exit.in(0) instanceof IfNode iff ) { CFGNode other = iff.cproj(1-exit._idx); if( other!=null && other.loopDepth() < loopDepth() ) - return stop; // Found an exit, not an infinite loop + return fun; // Found an exit, not an infinite loop } x = x.idom(); } @@ -57,6 +57,8 @@ public class LoopNode extends RegionNode { // XCtrl or a bunch of prior NeverNode exits. Node top = new ConstantNode(Type.TOP).peephole(); ReturnNode ret = fun.ret(); + iff._ltree = f._ltree = _ltree; + ret._ltree = t._ltree = fun._ltree; Node ctrl = ret.ctrl(), mem = ret.mem(), expr = ret.expr(); if( ctrl._type != Type.XCONTROL ) { // Perfect aligned exit? @@ -77,10 +79,11 @@ public class LoopNode extends RegionNode { mem = top; expr = top; } + ((CFGNode)ctrl)._ltree = fun._ltree; ret.setDef(0,ctrl); ret.setDef(1,mem ); ret.setDef(2,expr); - return stop; + return fun; } } diff --git a/chapter19/src/test/java/com/seaofnodes/simple/Chapter18Test.java b/chapter19/src/test/java/com/seaofnodes/simple/Chapter18Test.java index 81be3379..3ec63951 100644 --- a/chapter19/src/test/java/com/seaofnodes/simple/Chapter18Test.java +++ b/chapter19/src/test/java/com/seaofnodes/simple/Chapter18Test.java @@ -9,6 +9,42 @@ import static org.junit.Assert.fail; import org.junit.Ignore; public class Chapter18Test { + @Test public void testNeverExitLoopDepth() { + String[] sources = { + "if(arg) while(1) {} return 7;", + "if(arg==1) while(1) {} if(arg==2) while(1) {} return 7;", + "while(1) {}", + "int x=0; while(arg) { if(arg==2) while(1) { x++; } x++; arg--; } return x;" + }; + for( String src : sources ) { + CodeGen code = new CodeGen(src).parse().opto().typeCheck(); + code._start.buildLoopTree(code._stop); + int[] nevers = {0}; + code._stop.walk(n -> { + if( n instanceof FunNode fun ) + assertEquals("Function entry is outside its loops",0,fun.loopDepth()); + if( n instanceof ReturnNode ret ) { + assertEquals(ret.fun().loopDepth(),ret.loopDepth()); + assertEquals(ret.fun().loopDepth(),ret.cfg0().loopDepth()); + } + if( n instanceof LoopNode loop && !(loop instanceof StartNode) && + loop.back() instanceof CProjNode back && back.in(0) instanceof NeverNode never ) { + nevers[0]++; + assertSame(loop,never.loop()); + assertSame(loop,back.loop()); + CProjNode exit = never.cproj(1-back._idx); + CFGNode fun = loop; + while( !(fun instanceof FunNode) ) fun=fun.idom(); + assertSame(fun.loop(),exit.loop()); + assertEquals(fun.loopDepth(),exit.loopDepth()); + assertTrue(loop.loopDepth()>fun.loopDepth()); + } + return null; + }); + assertTrue("Exercise a synthetic exit",nevers[0]>0); + } + } + @Test public void testFunctionLocalConstantChains() { String src = "val f = { int x -> x ? f(x-1)*305420988+x/305420988 : 1; }; "+ "val g = { int x -> x ? g(x-1)/305420988+x*305420988 : 1; }; "+ |