Continuation capture always uses full liveness analysis.

Author: rakachan

espresso/src/com.oracle.truffle.espresso/src/com/oracle/truffle/espresso/EspressoOptions.java

@@ -703,7 +703,11 @@ public enum GuestFieldOffsetStrategyEnum {
                     stability = OptionStability.EXPERIMENTAL, //
                     usageSyntax = "false|true") public static final OptionKey<Boolean> EagerFrameAnalysis = new OptionKey<>(false);
 
-    /** Use a host property rather than an option. An option would slow interpreter considerably. */
+    /**
+     * Property used to force liveness analysis to also be applied by the interpreter. For testing
+     * purpose only. Use a host property rather than an option. An option would slow interpreter
+     * considerably.
+     */
     public static final boolean LivenessAnalysisInInterpreter = booleanProperty("espresso.liveness.interpreter", false);
 
     // Properties for FinalizationSupport e.g. --vm.Despresso.finalization.UnsafeOverride=false .

espresso/src/com.oracle.truffle.espresso/src/com/oracle/truffle/espresso/analysis/frame/FrameAnalysis.java

@@ -281,9 +281,9 @@ public final class FrameAnalysis implements StackMapFrameParser.FrameBuilder<Bui
     boolean withStackMaps;
 
     @TruffleBoundary
-    public static EspressoFrameDescriptor apply(Method.MethodVersion m, int bci) {
+    public static EspressoFrameDescriptor apply(Method.MethodVersion m, int bci, LivenessAnalysis la) {
         try {
-            return new FrameAnalysis(bci, m).apply();
+            return new FrameAnalysis(bci, m, la).apply();
         } catch (Exception e) {
             throw EspressoError.shouldNotReachHere(String.format("Failed suspension during frame analysis of method '%s'", m), e);
         }
@@ -301,9 +301,9 @@ public BytecodeStream stream() {
         return bs;
     }
 
-    private FrameAnalysis(int targetBci, Method.MethodVersion m) {
+    private FrameAnalysis(int targetBci, Method.MethodVersion m, LivenessAnalysis la) {
         this.lang = m.getMethod().getLanguage();
-        this.la = m.getLivenessAnalysis();
+        this.la = la;
         this.bs = new BytecodeStream(m.getOriginalCode());
         this.targetBci = targetBci;
         this.states = new Builder[bs.endBCI()];

espresso/src/com.oracle.truffle.espresso/src/com/oracle/truffle/espresso/analysis/liveness/LivenessAnalysis.java

@@ -36,6 +36,7 @@
 import com.oracle.truffle.api.CompilerDirectives.CompilationFinal;
 import com.oracle.truffle.api.frame.VirtualFrame;
 import com.oracle.truffle.espresso.EspressoLanguage;
+import com.oracle.truffle.espresso.EspressoOptions;
 import com.oracle.truffle.espresso.analysis.DepthFirstBlockIterator;
 import com.oracle.truffle.espresso.analysis.GraphBuilder;
 import com.oracle.truffle.espresso.analysis.Util;
@@ -46,6 +47,7 @@
 import com.oracle.truffle.espresso.analysis.liveness.actions.NullOutAction;
 import com.oracle.truffle.espresso.analysis.liveness.actions.SelectEdgeAction;
 import com.oracle.truffle.espresso.classfile.descriptors.Symbol;
+import com.oracle.truffle.espresso.impl.Klass;
 import com.oracle.truffle.espresso.impl.Method;
 import com.oracle.truffle.espresso.meta.EspressoError;
 import com.oracle.truffle.espresso.classfile.perf.DebugCloseable;
@@ -149,14 +151,15 @@ public boolean isEmpty() {
     }
 
     @SuppressWarnings("try")
-    public static LivenessAnalysis analyze(Method.MethodVersion methodVersion) {
+    public static LivenessAnalysis analyze(EspressoOptions.LivenessAnalysisMode mode, Method.MethodVersion methodVersion) {
 
         EspressoLanguage language = methodVersion.getMethod().getLanguage();
-        if (!enableLivenessAnalysis(language, methodVersion)) {
+        if (!enableLivenessAnalysis(mode, language, methodVersion)) {
             return NO_ANALYSIS;
         }
 
         Method method = methodVersion.getMethod();
+
         TimerCollection scope = method.getContext().getTimers();
         try (DebugCloseable liveness = LIVENESS_TIMER.scope(scope)) {
             Graph<? extends LinkedBlock> graph;
@@ -217,11 +220,11 @@ public static LivenessAnalysis analyze(Method.MethodVersion methodVersion) {
         }
     }
 
-    private static boolean enableLivenessAnalysis(EspressoLanguage language, Method.MethodVersion methodVersion) {
+    private static boolean enableLivenessAnalysis(EspressoOptions.LivenessAnalysisMode mode, EspressoLanguage language, Method.MethodVersion methodVersion) {
         if (isExempt(methodVersion.getMethod())) {
             return false;
         }
-        switch (language.getLivenessAnalysisMode()) {
+        switch (mode) {
             case NONE:
                 return false;
             case ALL:

espresso/src/com.oracle.truffle.espresso/src/com/oracle/truffle/espresso/impl/Method.java

@@ -1300,11 +1300,17 @@ public StaticObject apply(int j) {
     }
 
     private static final class Continuum {
+        Continuum(LivenessAnalysis livenessAnalysis) {
+            this.livenessAnalysis = livenessAnalysis;
+        }
+
         private record ContinuumData(int bci, CallTarget continuable, EspressoFrameDescriptor frameDescriptor) {
         }
 
         private static final ContinuumData[] EMPTY_DATA = new ContinuumData[0];
 
+        // Force Liveness Analysis for all method in a continuation frame record.
+        private final LivenessAnalysis livenessAnalysis;
         @CompilationFinal(dimensions = 1) //
         private volatile ContinuumData[] continuumData = EMPTY_DATA;
 
@@ -1326,7 +1332,7 @@ private ContinuumData getData(MethodVersion mv, int bci) {
                 }
                 int prevSize = continuumData.length;
                 localData = Arrays.copyOf(continuumData, prevSize + 1);
-                EspressoFrameDescriptor fd = FrameAnalysis.apply(mv, bci);
+                EspressoFrameDescriptor fd = FrameAnalysis.apply(mv, bci, livenessAnalysis);
                 CallTarget ct = EspressoRootNode.createContinuable(mv, bci, fd).getCallTarget();
                 ContinuumData data = new ContinuumData(bci, ct, fd);
                 localData[prevSize] = data;
@@ -1544,9 +1550,19 @@ public CallTarget getCallTarget() {
         private Continuum getContinuum() {
             if (continuum == null) {
                 CompilerDirectives.transferToInterpreterAndInvalidate();
+                // Compute LA out of lock.
+                LivenessAnalysis la = getLivenessAnalysis();
+                if (la.isEmpty()) {
+                    /*
+                     * Ensure we compute and use a full liveness analysis for all method in the
+                     * continuation records, so that the frame capture prunes as much unneeded data
+                     * as possible in order to make the records slimmer.
+                     */
+                    la = LivenessAnalysis.analyze(EspressoOptions.LivenessAnalysisMode.ALL, this);
+                }
                 synchronized (this) {
                     if (continuum == null) {
-                        Continuum c = new Continuum();
+                        Continuum c = new Continuum(la);
                         VarHandle.releaseFence();
                         continuum = c;
                     }
@@ -1920,7 +1936,7 @@ public LivenessAnalysis getLivenessAnalysis() {
                 synchronized (this) {
                     result = this.livenessAnalysis;
                     if (result == null) {
-                        this.livenessAnalysis = result = LivenessAnalysis.analyze(this);
+                        this.livenessAnalysis = result = LivenessAnalysis.analyze(getLanguage().getLivenessAnalysisMode(), this);
                     }
                 }
             }

espresso/src/com.oracle.truffle.espresso/src/com/oracle/truffle/espresso/impl/ObjectKlass.java

@@ -766,7 +766,7 @@ private static void eagerFrameAnalysis(Method m) {
         int nextBci = 0;
         while (nextBci < bs.endBCI()) {
             if (Bytecodes.isInvoke(bs.opcode(nextBci))) {
-                FrameAnalysis.apply(m.getMethodVersion(), nextBci);
+                FrameAnalysis.apply(m.getMethodVersion(), nextBci, m.getMethodVersion().getLivenessAnalysis());
             }
             nextBci = bs.nextBCI(nextBci);
         }