[Backport] [Oracle GraalVM] [GR-64916] Backport to 23.1: Stricter checks for CFG and schedule validity.

[elkorchi]

What would you like to backport?

Oracle GraalVM backported commits:

(oracle/graal@3d1f83a)

Describe the motivation for the backport.

Backported to Oracle GraalVM for JDK 21, fix version: graalvm-23.1.8

[bulasevich]

This is a tough backport. It requires to backport other changes:

oracle/graal@155ef73

Author: Raphael Mosaner <raphael.m.mosaner@oracle.com>
Date:   Tue May 7 10:53:07 2024 +0200

    [GR-53819] Use NodeEventListener for cache invalidation.

compiler/src/jdk.graal.compiler/src/jdk/graal/compiler/nodes/StructuredGraph.java
+    public boolean isLastCFGValid() {
+        return cacheInvalidationListener.lastCFGValid;
+    }

oracle/graal@534de4a

Author: Raphael Mosaner <raphael.m.mosaner@oracle.com>
Date:   Wed Apr 24 08:57:31 2024 +0200

    [GR-53819] CFG caching based on edge modification count.

compiler/src/jdk.graal.compiler/src/jdk/graal/compiler/nodes/StructuredGraph.java
+    public ControlFlowGraph getLastCFG() {
+        return lastCFG;
+    }

oracle/graal@aa386ae

Author: David Leopoldseder <david.leopoldseder@oracle.com>
Date:   Wed May 22 15:05:12 2024 +0200

    Add LateLoweredNode: A means to transplant a callee graph very late in
    the frontend into a caller graph.

compiler/src/jdk.graal.compiler/src/jdk/graal/compiler/nodes/GraphState.java
+        FINAL_SCHEDULE

oracle/graal@cf0c238

Author: Christian Wirth <christian.wirth@oracle.com>
Date:   Mon Nov 6 20:07:36 2023 +0100

    add Builder pattern to ControlFlowGraph

compiler/src/jdk.graal.compiler/src/jdk/graal/compiler/nodes/cfg/ControlFlowGraph.java
+    public static ControlFlowGraphBuilder newBuilder(StructuredGraph structuredGraph) {
+        return new ControlFlowGraphBuilder(structuredGraph);
+    }

oracle/graal@d450dc2

Author: Raphael Mosaner <raphael.m.mosaner@oracle.com>
Date:   Thu May 16 17:41:56 2024 +0200

    [GR-53819] Refactoring and documentation.

compiler/src/jdk.graal.compiler/src/jdk/graal/compiler/nodes/cfg/ControlFlowGraph.java
+    /**
+     * Returns the last {@link ControlFlowGraph} computed for the given {@link StructuredGraph} if
+     * this CFG is still valid and uses the specified type of {@link HIRBlock}s (modifiable or
+     * unmodifiable). Returns {@code null} otherwise.
+     */
+    private static ControlFlowGraph lookupCached(StructuredGraph graph, boolean modifiableBlocks) {
+        if (graph.isLastCFGValid()) {
+            ControlFlowGraph lastCFG = graph.getLastCFG();
+            assert lastCFG != null : "A valid lastCFG must not be null";
+            if (lastCFG.buildConfig.modifiableBlocks == modifiableBlocks) {
+                return lastCFG;
+            }
+        }
+        return null;
+    }

Otherwise, we either don’t have a changed text block at all, or we encounter build errors due to references to missing symbols:

• StructuredGraph.isLastCFGValid
• StructuredGraph.getLastCFG
• StageFlag.FINAL_SCHEDULE
• ControlFlowGraph.newBuilder

<<<<<<< HEAD:compiler/src/jdk.internal.vm.compiler/src/org/graalvm/compiler/phases/common/ConditionalEliminationPhase.java
                    SchedulePhase.run(graph, SchedulingStrategy.EARLIEST_WITH_GUARD_ORDER, cfg, context, false);
=======
                    if (!graph.isLastCFGValid()) {
                        cfg = null;
                    }
                    SchedulePhase.run(graph, SchedulePhase.SchedulingStrategy.EARLIEST_WITH_GUARD_ORDER, cfg, context, false);
                    cfg = graph.getLastCFG();
                    cfg.computePostdominators();
>>>>>>> 3d1f83ae69e (Stricter checks for CFG and schedule validity):compiler/src/jdk.graal.compiler/src/jdk/graal/compiler/phases/common/ConditionalEliminationPhase.java

/home/boris/graal-build-jdk21/graal/compiler/src/jdk.internal.vm.compiler/src/org/graalvm/compiler/phases/common/ConditionalEliminationPhase.java:205: error: cannot find symbol
                    if (!graph.isLastCFGValid()) {
                              ^
  symbol:   method isLastCFGValid()
  location: variable graph of type StructuredGraph
/home/boris/graal-build-jdk21/graal/compiler/src/jdk.internal.vm.compiler/src/org/graalvm/compiler/phases/common/ConditionalEliminationPhase.java:209: error: cannot find symbol
                    cfg = graph.getLastCFG();
                               ^
  symbol:   method getLastCFG()

<<<<<<< HEAD:compiler/src/jdk.internal.vm.compiler/src/org/graalvm/compiler/nodes/cfg/ControlFlowGraph.java
    private void identifyBlocks(boolean makeEditable) {
=======
    /**
     * Returns the last {@link ControlFlowGraph} computed for the given {@link StructuredGraph} if
     * this CFG is still valid and uses the specified type of {@link HIRBlock}s (modifiable or
     * unmodifiable). Returns {@code null} otherwise.
     */
    private static ControlFlowGraph lookupCached(StructuredGraph graph, boolean modifiableBlocks) {
        if (graph.isLastCFGValid()) {
            ControlFlowGraph lastCFG = graph.getLastCFG();
            assert lastCFG != null : "A valid lastCFG must not be null";
            if (lastCFG.buildConfig.modifiableBlocks == modifiableBlocks) {
                return lastCFG;
            }
        }
        if (graph.getLastSchedule() != null && !graph.isAfterStage(GraphState.StageFlag.FINAL_SCHEDULE)) {
            /*
             * There is no up to date CFG. If there is a current schedule, its CFG must also be out
             * of date. So invalidate the schedule. The only exception is during cleanup phases
             * after final scheduling, where we don't want to destroy that schedule.
             */
            graph.clearLastSchedule();
        }
        return null;
    }

    /**
     * Contains all flags which were used for building this CFG.
     */
    private static final class BuildConfiguration {
        private boolean modifiableBlocks = false;
        private boolean connectBlocks = false;
        private boolean frequenciesComputed = false;
        private boolean loopsComputed = false;
        private boolean dominatorsComputed = false;
        private boolean postdominatorsComputed = false;

        /**
         * Checks that this build configuration is not weaker than a build configuration from the
         * provided parameters. That is, if for each parameter p the following holds:
         * {@code (p -> this.p)} which is equivalent to {@code (!p || this.p)}.
         */
        @SuppressWarnings("hiding")
        public boolean notWeakerThan(boolean connectBlocks, boolean computeFrequency, boolean computeLoops, boolean computeDominators, boolean computePostdominators) {
            return (this.connectBlocks || !connectBlocks) && (this.frequenciesComputed || !computeFrequency) && (this.loopsComputed || !computeLoops) &&
                            (this.dominatorsComputed || !computeDominators) && (this.postdominatorsComputed || !computePostdominators);
        }
    }

    private void identifyBlocks(boolean makeModifiable) {
>>>>>>> 3d1f83ae69e (Stricter checks for CFG and schedule validity):compiler/src/jdk.graal.compiler/src/jdk/graal/compiler/nodes/cfg/ControlFlowGraph.java

/home/boris/graal-build-jdk21/graal/compiler/src/jdk.internal.vm.compiler/src/org/graalvm/compiler/nodes/loop/LoopsData.java:68: error: cannot find symbol
                boolean backendBlocks = graph.isAfterStage(GraphState.StageFlag.FINAL_SCHEDULE);
                                                                               ^
  symbol:   variable FINAL_SCHEDULE
  location: class StageFlag

<<<<<<< HEAD:compiler/src/jdk.internal.vm.compiler/src/org/graalvm/compiler/nodes/loop/LoopsData.java
                this.cfg = ControlFlowGraph.compute(graph, true, true, true, true);
=======
                boolean backendBlocks = graph.isAfterStage(GraphState.StageFlag.FINAL_SCHEDULE);
                this.cfg = ControlFlowGraph.newBuilder(graph).connectBlocks(true).backendBlocks(backendBlocks).computeLoops(true).computeDominators(true).computePostdominators(true).computeFrequency(
                                true).build();
>>>>>>> 3d1f83ae69e (Stricter checks for CFG and schedule validity):compiler/src/jdk.graal.compiler/src/jdk/graal/compiler/nodes/loop/LoopsData.java

/home/boris/graal-build-jdk21/graal/compiler/src/jdk.internal.vm.compiler/src/org/graalvm/compiler/nodes/loop/LoopsData.java:69: error: cannot find symbol
                this.cfg = ControlFlowGraph.newBuilder(graph).connectBlocks(true).backendBlocks(backendBlocks).computeLoops(true).computeDominators(true).computePostdominators(true).computeFrequency(
                                           ^
  symbol:   method newBuilder(StructuredGraph)
  location: class ControlFlowGraph

/home/boris/graal-build-jdk21/graal/compiler/src/jdk.internal.vm.compiler/src/org/graalvm/compiler/phases/schedule/SchedulePhase.java:222: error: cannot find symbol
                GraalError.guarantee(this.cfg == graph.getLastCFG() && graph.isLastCFGValid(),
                                                      ^
  symbol:   method getLastCFG()
  location: variable graph of type StructuredGraph
/home/boris/graal-build-jdk21/graal/compiler/src/jdk.internal.vm.compiler/src/org/graalvm/compiler/phases/schedule/SchedulePhase.java:222: error: cannot find symbol
                GraalError.guarantee(this.cfg == graph.getLastCFG() && graph.isLastCFGValid(),
                                                                            ^
  symbol:   method isLastCFGValid()
  location: variable graph of type StructuredGraph
/home/boris/graal-build-jdk21/graal/compiler/src/jdk.internal.vm.compiler/src/org/graalvm/compiler/phases/schedule/SchedulePhase.java:224: error: cannot find symbol
                                this.cfg, graph.getLastCFG(), graph.isLastCFGValid());
                                               ^
  symbol:   method getLastCFG()
  location: variable graph of type StructuredGraph
/home/boris/graal-build-jdk21/graal/compiler/src/jdk.internal.vm.compiler/src/org/graalvm/compiler/phases/schedule/SchedulePhase.java:224: error: cannot find symbol
                                this.cfg, graph.getLastCFG(), graph.isLastCFGValid());
                                                                   ^
  symbol:   method isLastCFGValid()
  location: variable graph of type StructuredGraph