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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * particular file as subject to the "Classpath" exception as provided
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 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
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 *
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package org.graalvm.compiler.hotspot;

import static java.util.Collections.emptyList;
import static java.util.Collections.unmodifiableList;
import static org.graalvm.compiler.hotspot.HotSpotCompiledCodeBuilder.Options.ShowSubstitutionSourceInfo;
import static org.graalvm.util.CollectionsUtil.anyMatch;

import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.EnumMap;
import java.util.List;
import java.util.ListIterator;
import java.util.Map;

import org.graalvm.compiler.code.CompilationResult;
import org.graalvm.compiler.code.CompilationResult.CodeAnnotation;
import org.graalvm.compiler.code.CompilationResult.CodeComment;
import org.graalvm.compiler.code.CompilationResult.CodeMark;
import org.graalvm.compiler.code.CompilationResult.JumpTable;
import org.graalvm.compiler.code.DataSection;
import org.graalvm.compiler.code.SourceMapping;
import org.graalvm.compiler.debug.GraalError;
import org.graalvm.compiler.graph.NodeSourcePosition;
import org.graalvm.compiler.options.Option;
import org.graalvm.compiler.options.OptionKey;
import org.graalvm.compiler.options.OptionValues;

import jdk.vm.ci.code.BytecodeFrame;
import jdk.vm.ci.code.CodeCacheProvider;
import jdk.vm.ci.code.DebugInfo;
import jdk.vm.ci.code.StackSlot;
import jdk.vm.ci.code.site.ConstantReference;
import jdk.vm.ci.code.site.DataPatch;
import jdk.vm.ci.code.site.Infopoint;
import jdk.vm.ci.code.site.InfopointReason;
import jdk.vm.ci.code.site.Mark;
import jdk.vm.ci.code.site.Site;
import jdk.vm.ci.hotspot.HotSpotCompilationRequest;
import jdk.vm.ci.hotspot.HotSpotCompiledCode;
import jdk.vm.ci.hotspot.HotSpotCompiledCode.Comment;
import jdk.vm.ci.hotspot.HotSpotCompiledNmethod;
import jdk.vm.ci.hotspot.HotSpotResolvedJavaMethod;
import jdk.vm.ci.meta.Assumptions.Assumption;
import jdk.vm.ci.meta.ResolvedJavaMethod;

public class HotSpotCompiledCodeBuilder {
    public static HotSpotCompiledCode createCompiledCode(CodeCacheProvider codeCache, ResolvedJavaMethod method, HotSpotCompilationRequest compRequest, CompilationResult compResult,
                    OptionValues options) {
        String name = compResult.getName();

        byte[] targetCode = compResult.getTargetCode();
        int targetCodeSize = compResult.getTargetCodeSize();

        Site[] sites = getSortedSites(compResult, options, codeCache.shouldDebugNonSafepoints() && method != null);
        assert verifySiteMethods(sites);

        Assumption[] assumptions = compResult.getAssumptions();

        ResolvedJavaMethod[] methods = filterMethods(compResult.getMethods());

        List<CodeAnnotation> annotations = compResult.getCodeAnnotations();
        Comment[] comments = new Comment[annotations.size()];
        if (!annotations.isEmpty()) {
            for (int i = 0; i < comments.length; i++) {
                CodeAnnotation annotation = annotations.get(i);
                String text;
                if (annotation instanceof CodeComment) {
                    CodeComment codeComment = (CodeComment) annotation;
                    text = codeComment.value;
                } else if (annotation instanceof JumpTable) {
                    JumpTable jumpTable = (JumpTable) annotation;
                    text = "JumpTable [" + jumpTable.low + " .. " + jumpTable.high + "]";
                } else {
                    text = annotation.toString();
                }
                comments[i] = new Comment(annotation.getPosition(), text);
            }
        }

        DataSection data = compResult.getDataSection();
        byte[] dataSection = new byte[data.getSectionSize()];

        ByteBuffer buffer = ByteBuffer.wrap(dataSection).order(ByteOrder.nativeOrder());
        List<DataPatch> patches = new ArrayList<>();
        data.buildDataSection(buffer, (position, vmConstant) -> {
            patches.add(new DataPatch(position, new ConstantReference(vmConstant)));
        });

        int dataSectionAlignment = data.getSectionAlignment();
        DataPatch[] dataSectionPatches = patches.toArray(new DataPatch[patches.size()]);

        int totalFrameSize = compResult.getTotalFrameSize();
        StackSlot customStackArea = compResult.getCustomStackArea();
        boolean isImmutablePIC = compResult.isImmutablePIC();

        if (method instanceof HotSpotResolvedJavaMethod) {
            HotSpotResolvedJavaMethod hsMethod = (HotSpotResolvedJavaMethod) method;
            int entryBCI = compResult.getEntryBCI();
            boolean hasUnsafeAccess = compResult.hasUnsafeAccess();

            int id;
            long jvmciCompileState;
            if (compRequest != null) {
                id = compRequest.getId();
                jvmciCompileState = compRequest.getJvmciEnv();
            } else {
                id = hsMethod.allocateCompileId(entryBCI);
                jvmciCompileState = 0L;
            }
            return new HotSpotCompiledNmethod(name, targetCode, targetCodeSize, sites, assumptions, methods, comments, dataSection, dataSectionAlignment, dataSectionPatches, isImmutablePIC,
                            totalFrameSize, customStackArea, hsMethod, entryBCI, id, jvmciCompileState, hasUnsafeAccess);
        } else {
            return new HotSpotCompiledCode(name, targetCode, targetCodeSize, sites, assumptions, methods, comments, dataSection, dataSectionAlignment, dataSectionPatches, isImmutablePIC,
                            totalFrameSize, customStackArea);
        }
    }

    
Ensure that only real HotSpotResolvedJavaMethods appear in debug info. /**
     * Ensure that only real {@link HotSpotResolvedJavaMethod HotSpotResolvedJavaMethods} appear in
     * debug info.
     */
    private static boolean verifySiteMethods(Site[] sites) {
        for (Site site : sites) {
            if (site instanceof Infopoint) {
                Infopoint infopoint = (Infopoint) site;
                if (infopoint.debugInfo != null) {
                    BytecodeFrame frame = infopoint.debugInfo.frame();
                    while (frame != null) {
                        assert frame.getMethod() instanceof HotSpotResolvedJavaMethod;
                        frame = frame.caller();
                    }
                }
            }
        }
        return true;
    }

    private static ResolvedJavaMethod[] filterMethods(ResolvedJavaMethod[] methods) {
        if (methods != null) {
            ArrayList<ResolvedJavaMethod> hsMethods = null;
            int i = 0;
            while (i < methods.length) {
                ResolvedJavaMethod method = methods[i];
                if (hsMethods != null) {
                    if (method instanceof HotSpotResolvedJavaMethod) {
                        hsMethods.add(method);
                    }
                } else if (!(method instanceof HotSpotResolvedJavaMethod)) {
                    hsMethods = new ArrayList<>();
                    i = 0;
                    continue;
                }
                i++;
            }
            if (hsMethods != null) {
                return hsMethods.toArray(new ResolvedJavaMethod[hsMethods.size()]);
            }
        }

        return methods;
    }

    
Returns:
the list of marks converted from the CodeMarks./**
     * @return the list of {@link Mark marks} converted from the {@link CodeMark CodeMarks}.
     */
    private static List<Mark> getTranslatedMarks(List<CodeMark> codeMarks) {
        if (codeMarks.isEmpty()) {
            return emptyList();
        }
        // The HotSpot backend needs these in the exact form of a Mark so convert all the marks
        // to that form.
        List<Mark> translated = new ArrayList<>(codeMarks.size());
        for (CodeMark m : codeMarks) {
            translated.add(new Mark(m.pcOffset, m.id.getId()));
        }
        return unmodifiableList(translated);
    }

    
HotSpot expects sites to be presented in ascending order of PC (see DebugInformationRecorder::add_new_pc_offset). In addition, it expects Infopoint PCs to be unique. /**
     * HotSpot expects sites to be presented in ascending order of PC (see
     * {@code DebugInformationRecorder::add_new_pc_offset}). In addition, it expects
     * {@link Infopoint} PCs to be unique.
     */
    private static Site[] getSortedSites(CompilationResult target, OptionValues options, boolean includeSourceInfo) {
        List<Site> sites = new ArrayList<>(
                        target.getExceptionHandlers().size() + target.getInfopoints().size() + target.getDataPatches().size() + target.getMarks().size() + target.getSourceMappings().size());
        sites.addAll(target.getExceptionHandlers());
        sites.addAll(target.getInfopoints());
        sites.addAll(target.getDataPatches());
        sites.addAll(getTranslatedMarks(target.getMarks()));

        if (includeSourceInfo) {
            /*
             * Translate the source mapping into appropriate info points. In HotSpot only one
             * position can really be represented and recording the end PC seems to give the best
             * results and corresponds with what C1 and C2 do. HotSpot doesn't like to see these
             * unless -XX:+DebugNonSafepoints is enabled, so don't emit them in that case.
             */

            List<SourceMapping> sourceMappings = new ArrayList<>();
            ListIterator<SourceMapping> sourceMappingListIterator = target.getSourceMappings().listIterator();
            if (sourceMappingListIterator.hasNext()) {
                SourceMapping currentSource = sourceMappingListIterator.next();
                NodeSourcePosition sourcePosition = currentSource.getSourcePosition();
                if (!sourcePosition.isPlaceholder() && !sourcePosition.isSubstitution()) {
                    sourceMappings.add(currentSource);
                }
                while (sourceMappingListIterator.hasNext()) {
                    SourceMapping nextSource = sourceMappingListIterator.next();
                    assert currentSource.getStartOffset() <= nextSource.getStartOffset() : "Must be presorted";
                    currentSource = nextSource;
                    sourcePosition = currentSource.getSourcePosition();
                    if (!sourcePosition.isPlaceholder() && !sourcePosition.isSubstitution()) {
                        sourceMappings.add(currentSource);
                    }
                }
            }

            /*
             * Don't add BYTECODE_POSITION info points that would potentially create conflicts.
             * Under certain conditions the site's pc is not the pc that gets recorded by HotSpot
             * (see @code {CodeInstaller::site_Call}). So, avoid adding any source positions that
             * can potentially map to the same pc. To do that the following code makes sure that the
             * source mapping doesn't contain a pc of any important Site.
             */
            sites.sort(new SiteComparator());

            ListIterator<Site> siteListIterator = sites.listIterator();
            sourceMappingListIterator = sourceMappings.listIterator();

            List<Site> sourcePositionSites = new ArrayList<>();
            Site site = null;

            // Iterate over sourceMappings and sites in parallel. Create source position infopoints
            // only for source mappings that don't have any sites inside their intervals.
            while (sourceMappingListIterator.hasNext()) {
                SourceMapping source = sourceMappingListIterator.next();

                // Skip sites before the current source mapping
                if (site == null || site.pcOffset < source.getStartOffset()) {
                    while (siteListIterator.hasNext()) {
                        site = siteListIterator.next();
                        if (site.pcOffset >= source.getStartOffset()) {
                            break;
                        }
                    }
                }
                assert !siteListIterator.hasNext() || (site != null && site.pcOffset >= source.getStartOffset());
                if (site != null && source.getStartOffset() <= site.pcOffset && site.pcOffset <= source.getEndOffset()) {
                    // Conflicting source mapping, skip it.
                    continue;
                } else {
                    // Since the sites are sorted there can not be any more sites in this interval.
                }
                assert !siteListIterator.hasNext() || (site != null && site.pcOffset > source.getEndOffset());
                // Good source mapping. Create an infopoint and add it to the list.
                NodeSourcePosition sourcePosition = source.getSourcePosition();
                assert sourcePosition.verify();
                if (!ShowSubstitutionSourceInfo.getValue(options)) {
                    sourcePosition = sourcePosition.trim();
                    assert verifyTrim(sourcePosition);
                }
                while (sourcePosition != null && !(sourcePosition.getMethod() instanceof HotSpotResolvedJavaMethod)) {
                    sourcePosition = sourcePosition.getCaller();
                }
                if (sourcePosition != null) {
                    assert !anyMatch(sites, s -> source.getStartOffset() <= s.pcOffset && s.pcOffset <= source.getEndOffset());
                    sourcePositionSites.add(new Infopoint(source.getEndOffset(), new DebugInfo(sourcePosition), InfopointReason.BYTECODE_POSITION));
                }
            }

            sites.addAll(sourcePositionSites);
        }

        SiteComparator c = new SiteComparator();
        Collections.sort(sites, c);

        if (c.sawCollidingInfopoints) {
            Infopoint lastInfopoint = null;
            List<Site> copy = new ArrayList<>(sites.size());
            for (Site site : sites) {
                if (site instanceof Infopoint) {
                    Infopoint info = (Infopoint) site;
                    if (lastInfopoint == null || lastInfopoint.pcOffset != info.pcOffset) {
                        lastInfopoint = info;
                        copy.add(info);
                    } else {
                        // Omit this colliding infopoint
                        assert lastInfopoint.reason.compareTo(info.reason) <= 0;
                    }
                } else {
                    copy.add(site);
                }
            }
            sites = copy;
        }

        return sites.toArray(new Site[sites.size()]);
    }

    private static boolean verifyTrim(NodeSourcePosition sourcePosition) {
        for (NodeSourcePosition sp = sourcePosition; sp != null; sp = sp.getCaller()) {
            assert !sp.isSubstitution();
        }
        return true;
    }

    public static class Options {
        // @formatter:off
        @Option(help = "Controls whether the source position information of snippets and method substitutions" +
                " are exposed to HotSpot.  Can be useful when profiling to get more precise position information.")
        public static final OptionKey<Boolean> ShowSubstitutionSourceInfo = new OptionKey<>(false);
    }

    static class SiteComparator implements Comparator<Site> {

        
Defines an order for sorting Infopoints based on their reasons. This is used to choose which infopoint to preserve when multiple infopoints collide on the same PC offset. A negative order value implies a non-optional infopoint (i.e., must be preserved). /**
         * Defines an order for sorting {@link Infopoint}s based on their
         * {@linkplain Infopoint#reason reasons}. This is used to choose which infopoint to preserve
         * when multiple infopoints collide on the same PC offset. A negative order value implies a
         * non-optional infopoint (i.e., must be preserved).
         */
        static final Map<InfopointReason, Integer> HOTSPOT_INFOPOINT_SORT_ORDER = new EnumMap<>(InfopointReason.class);

        static {
            HOTSPOT_INFOPOINT_SORT_ORDER.put(InfopointReason.SAFEPOINT, -4);
            HOTSPOT_INFOPOINT_SORT_ORDER.put(InfopointReason.CALL, -3);
            HOTSPOT_INFOPOINT_SORT_ORDER.put(InfopointReason.IMPLICIT_EXCEPTION, -2);
            HOTSPOT_INFOPOINT_SORT_ORDER.put(InfopointReason.METHOD_START, 2);
            HOTSPOT_INFOPOINT_SORT_ORDER.put(InfopointReason.METHOD_END, 3);
            HOTSPOT_INFOPOINT_SORT_ORDER.put(InfopointReason.BYTECODE_POSITION, 4);
        }

        
Records whether any two Infopoints had the same Site.pcOffset. /**
         * Records whether any two {@link Infopoint}s had the same {@link Infopoint#pcOffset}.
         */
        boolean sawCollidingInfopoints;

        static int ord(Infopoint info) {
            return HOTSPOT_INFOPOINT_SORT_ORDER.get(info.reason);
        }

        static int checkCollision(Infopoint i1, Infopoint i2) {
            int o1 = ord(i1);
            int o2 = ord(i2);
            if (o1 < 0 && o2 < 0) {
                throw new GraalError("Non optional infopoints cannot collide: %s and %s", i1, i2);
            }
            return o1 - o2;
        }

        @Override
        public int compare(Site s1, Site s2) {
            if (s1.pcOffset == s2.pcOffset) {
                // Marks must come first since patching a call site
                // may need to know the mark denoting the call type
                // (see uses of CodeInstaller::_next_call_type).
                boolean s1IsMark = s1 instanceof Mark;
                boolean s2IsMark = s2 instanceof Mark;
                if (s1IsMark != s2IsMark) {
                    return s1IsMark ? -1 : 1;
                }

                // Infopoints must group together so put them after
                // other Site types.
                boolean s1IsInfopoint = s1 instanceof Infopoint;
                boolean s2IsInfopoint = s2 instanceof Infopoint;
                if (s1IsInfopoint != s2IsInfopoint) {
                    return s1IsInfopoint ? 1 : -1;
                }

                if (s1IsInfopoint) {
                    sawCollidingInfopoints = true;
                    return checkCollision((Infopoint) s1, (Infopoint) s2);
                }
            }
            return s1.pcOffset - s2.pcOffset;
        }
    }
}