/*

 * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * 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,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package org.graalvm.compiler.phases.verify;

import static org.graalvm.compiler.debug.DebugContext.BASIC_LEVEL;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.HashSet;

import java.util.List;

import java.util.Set;

import org.graalvm.compiler.core.common.type.ObjectStamp;

import org.graalvm.compiler.debug.DebugContext;

import org.graalvm.compiler.debug.GraalError;

import org.graalvm.compiler.graph.Graph;

import org.graalvm.compiler.graph.Node;

import org.graalvm.compiler.graph.NodeInputList;

import org.graalvm.compiler.nodes.CallTargetNode;

import org.graalvm.compiler.nodes.Invoke;

import org.graalvm.compiler.nodes.NodeView;

import org.graalvm.compiler.nodes.StructuredGraph;

import org.graalvm.compiler.nodes.ValueNode;

import org.graalvm.compiler.nodes.java.MethodCallTargetNode;

import org.graalvm.compiler.nodes.java.NewArrayNode;

import org.graalvm.compiler.nodes.java.StoreIndexedNode;

import org.graalvm.compiler.phases.VerifyPhase;

import org.graalvm.compiler.phases.tiers.PhaseContext;

import jdk.vm.ci.meta.Constant;

import jdk.vm.ci.meta.MetaAccessProvider;

import jdk.vm.ci.meta.PrimitiveConstant;

import jdk.vm.ci.meta.ResolvedJavaMethod;

import jdk.vm.ci.meta.ResolvedJavaType;

/**

 * Verifies that call sites calling one of the methods in {@link DebugContext} use them correctly.

 * Correct usage of the methods in {@link DebugContext} requires call sites to not eagerly evaluate

 * their arguments. Additionally this phase verifies that no argument is the result of a call to

 * {@link StringBuilder#toString()} or {@link StringBuffer#toString()}. Ideally the parameters at

 * call sites of {@link DebugContext} are eliminated, and do not produce additional allocations, if

 * {@link DebugContext#isDumpEnabled(int)} (or {@link DebugContext#isLogEnabled(int)}, ...) is

 * {@code false}.

 *

 * Methods in {@link DebugContext} checked by this phase are various different versions of

 * {@link DebugContext#log(String)} , {@link DebugContext#dump(int, Object, String)},

 * {@link DebugContext#logAndIndent(String)} and {@link DebugContext#verify(Object, String)}.

 */

public class VerifyDebugUsage extends VerifyPhase<PhaseContext> {

    @Override

    public boolean checkContract() {

        return false;

    }

    MetaAccessProvider metaAccess;

    @Override

    protected boolean verify(StructuredGraph graph, PhaseContext context) {

        metaAccess = context.getMetaAccess();

        ResolvedJavaType debugType = metaAccess.lookupJavaType(DebugContext.class);

        ResolvedJavaType nodeType = metaAccess.lookupJavaType(Node.class);

        ResolvedJavaType stringType = metaAccess.lookupJavaType(String.class);

        ResolvedJavaType graalErrorType = metaAccess.lookupJavaType(GraalError.class);

        for (MethodCallTargetNode t : graph.getNodes(MethodCallTargetNode.TYPE)) {

            ResolvedJavaMethod callee = t.targetMethod();

            String calleeName = callee.getName();

            if (callee.getDeclaringClass().equals(debugType)) {

                boolean isDump = calleeName.equals("dump");

                if (calleeName.equals("log") || calleeName.equals("logAndIndent") || calleeName.equals("verify") || isDump) {

                    verifyParameters(t, graph, t.arguments(), stringType, isDump ? 2 : 1);

                }

            }

            if (callee.getDeclaringClass().isAssignableFrom(nodeType)) {

                if (calleeName.equals("assertTrue") || calleeName.equals("assertFalse")) {

                    verifyParameters(t, graph, t.arguments(), stringType, 1);

                }

            }

            if (callee.getDeclaringClass().isAssignableFrom(graalErrorType) && !graph.method().getDeclaringClass().isAssignableFrom(graalErrorType)) {

                if (calleeName.equals("guarantee")) {

                    verifyParameters(t, graph, t.arguments(), stringType, 0);

                }

                if (calleeName.equals("<init>") && callee.getSignature().getParameterCount(false) == 2) {

                    verifyParameters(t, graph, t.arguments(), stringType, 1);

                }

            }

        }

        return true;

    }

    private void verifyParameters(MethodCallTargetNode callTarget, StructuredGraph callerGraph, NodeInputList<? extends ValueNode> args, ResolvedJavaType stringType, int startArgIdx) {

        if (callTarget.targetMethod().isVarArgs() && args.get(args.count() - 1) instanceof NewArrayNode) {

            // unpack the arguments to the var args

            List<ValueNode> unpacked = new ArrayList<>(args.snapshot());

            NewArrayNode varArgParameter = (NewArrayNode) unpacked.remove(unpacked.size() - 1);

            int firstVarArg = unpacked.size();

            for (Node usage : varArgParameter.usages()) {

                if (usage instanceof StoreIndexedNode) {

                    StoreIndexedNode si = (StoreIndexedNode) usage;

                    unpacked.add(si.value());

                }

            }

            verifyParameters(callerGraph, callTarget, unpacked, stringType, startArgIdx, firstVarArg);

        } else {

            verifyParameters(callerGraph, callTarget, args, stringType, startArgIdx, -1);

        }

    }

    private static final Set<Integer> DebugLevels = new HashSet<>(

                    Arrays.asList(DebugContext.ENABLED_LEVEL, BASIC_LEVEL, DebugContext.INFO_LEVEL, DebugContext.VERBOSE_LEVEL, DebugContext.DETAILED_LEVEL, DebugContext.VERY_DETAILED_LEVEL));

    /**

     * The set of methods allowed to call a {@code Debug.dump(...)} method with the {@code level}

     * parameter bound to {@link DebugContext#BASIC_LEVEL} and the {@code object} parameter bound to

     * a {@link StructuredGraph} value.

     *

     * This whitelist exists to ensure any increase in graph dumps is in line with the policy

     * outlined by {@link DebugContext#BASIC_LEVEL}. If you add a *justified* graph dump at this

     * level, then update the whitelist.

     */

    private static final Set<String> BasicLevelStructuredGraphDumpWhitelist = new HashSet<>(Arrays.asList(

                    "org.graalvm.compiler.phases.BasePhase.dumpAfter",

                    "org.graalvm.compiler.phases.BasePhase.dumpBefore",

                    "org.graalvm.compiler.core.GraalCompiler.emitFrontEnd",

                    "org.graalvm.compiler.core.test.VerifyDebugUsageTest$ValidDumpUsagePhase.run",

                    "org.graalvm.compiler.core.test.VerifyDebugUsageTest$InvalidConcatDumpUsagePhase.run",

                    "org.graalvm.compiler.core.test.VerifyDebugUsageTest$InvalidDumpUsagePhase.run"));

    /**

     * The set of methods allowed to call a {@code Debug.dump(...)} method with the {@code level}

     * parameter bound to {@link DebugContext#INFO_LEVEL} and the {@code object} parameter bound to

     * a {@link StructuredGraph} value.

     *

     * This whitelist exists to ensure any increase in graph dumps is in line with the policy

     * outlined by {@link DebugContext#INFO_LEVEL}. If you add a *justified* graph dump at this

     * level, then update the whitelist.

     */

    private static final Set<String> InfoLevelStructuredGraphDumpWhitelist = new HashSet<>(Arrays.asList(

                    "org.graalvm.compiler.core.GraalCompiler.emitFrontEnd",

                    "org.graalvm.compiler.phases.BasePhase.dumpAfter",

                    "org.graalvm.compiler.replacements.ReplacementsImpl$GraphMaker.makeGraph",

                    "org.graalvm.compiler.replacements.SnippetTemplate.instantiate"));

    private void verifyParameters(StructuredGraph callerGraph, MethodCallTargetNode debugCallTarget, List<? extends ValueNode> args, ResolvedJavaType stringType, int startArgIdx,

                    int varArgsIndex) {

        ResolvedJavaMethod verifiedCallee = debugCallTarget.targetMethod();

        Integer dumpLevel = null;

        int argIdx = startArgIdx;

        int varArgsElementIndex = 0;

        boolean reportVarArgs = false;

        for (int i = 0; i < args.size(); i++) {

            ValueNode arg = args.get(i);

            if (arg instanceof Invoke) {

                reportVarArgs = varArgsIndex >= 0 && argIdx >= varArgsIndex;

                Invoke invoke = (Invoke) arg;

                CallTargetNode callTarget = invoke.callTarget();

                if (callTarget instanceof MethodCallTargetNode) {

                    ResolvedJavaMethod m = ((MethodCallTargetNode) callTarget).targetMethod();

                    if (m.getName().equals("toString")) {

                        int bci = invoke.bci();

                        int nonVarArgIdx = reportVarArgs ? argIdx - varArgsElementIndex : argIdx;

                        verifyStringConcat(callerGraph, verifiedCallee, bci, nonVarArgIdx, reportVarArgs ? varArgsElementIndex : -1, m);

                        verifyToStringCall(callerGraph, verifiedCallee, stringType, m, bci, nonVarArgIdx, reportVarArgs ? varArgsElementIndex : -1);

                    } else if (m.getName().equals("format")) {

                        int bci = invoke.bci();

                        int nonVarArgIdx = reportVarArgs ? argIdx - varArgsElementIndex : argIdx;

                        verifyFormatCall(callerGraph, verifiedCallee, stringType, m, bci, nonVarArgIdx, reportVarArgs ? varArgsElementIndex : -1);

                    }

                }

            }

            if (i == 1) {

                if (verifiedCallee.getName().equals("dump")) {

                    dumpLevel = verifyDumpLevelParameter(callerGraph, debugCallTarget, verifiedCallee, arg);

                }

            } else if (i == 2) {

                if (dumpLevel != null) {

                    verifyDumpObjectParameter(callerGraph, debugCallTarget, arg, verifiedCallee, dumpLevel);

                }

            }

            if (varArgsIndex >= 0 && i >= varArgsIndex) {

                varArgsElementIndex++;

            }

            argIdx++;

        }

    }

    /**

     * The {@code level} arg for the {@code Debug.dump(...)} methods must be a reference to one of

     * the {@code Debug.*_LEVEL} constants.

     */

    protected Integer verifyDumpLevelParameter(StructuredGraph callerGraph, MethodCallTargetNode debugCallTarget, ResolvedJavaMethod verifiedCallee, ValueNode arg)

                    throws org.graalvm.compiler.phases.VerifyPhase.VerificationError {

        // The 'level' arg for the Debug.dump(...) methods must be a reference to one of

        // the Debug.*_LEVEL constants.

        Constant c = arg.asConstant();

        if (c != null) {

            Integer dumpLevel = ((PrimitiveConstant) c).asInt();

            if (!DebugLevels.contains(dumpLevel)) {

                StackTraceElement e = callerGraph.method().asStackTraceElement(debugCallTarget.invoke().bci());

                throw new VerificationError(

                                "In %s: parameter 0 of call to %s does not match a Debug.*_LEVEL constant: %s.%n", e, verifiedCallee.format("%H.%n(%p)"), dumpLevel);

            }

            return dumpLevel;

        }

        StackTraceElement e = callerGraph.method().asStackTraceElement(debugCallTarget.invoke().bci());

        throw new VerificationError(

                        "In %s: parameter 0 of call to %s must be a constant, not %s.%n", e, verifiedCallee.format("%H.%n(%p)"), arg);

    }

    protected void verifyDumpObjectParameter(StructuredGraph callerGraph, MethodCallTargetNode debugCallTarget, ValueNode arg, ResolvedJavaMethod verifiedCallee, Integer dumpLevel)

                    throws org.graalvm.compiler.phases.VerifyPhase.VerificationError {

        ResolvedJavaType argType = ((ObjectStamp) arg.stamp(NodeView.DEFAULT)).type();

        if (metaAccess.lookupJavaType(Graph.class).isAssignableFrom(argType)) {

            verifyStructuredGraphDumping(callerGraph, debugCallTarget, verifiedCallee, dumpLevel);

        }

    }

    /**

     * Verifies that dumping a {@link StructuredGraph} at level {@link DebugContext#BASIC_LEVEL} or

     * {@link DebugContext#INFO_LEVEL} only occurs in white-listed methods.

     */

    protected void verifyStructuredGraphDumping(StructuredGraph callerGraph, MethodCallTargetNode debugCallTarget, ResolvedJavaMethod verifiedCallee, Integer dumpLevel)

                    throws org.graalvm.compiler.phases.VerifyPhase.VerificationError {

        if (dumpLevel == DebugContext.BASIC_LEVEL) {

            StackTraceElement e = callerGraph.method().asStackTraceElement(debugCallTarget.invoke().bci());

            String qualifiedMethod = e.getClassName() + "." + e.getMethodName();

            if (!BasicLevelStructuredGraphDumpWhitelist.contains(qualifiedMethod)) {

                throw new VerificationError(

                                "In %s: call to %s with level == DebugContext.BASIC_LEVEL not in %s.BasicLevelDumpWhitelist.%n", e, verifiedCallee.format("%H.%n(%p)"),

                                getClass().getName());

            }

        } else if (dumpLevel == DebugContext.INFO_LEVEL) {

            StackTraceElement e = callerGraph.method().asStackTraceElement(debugCallTarget.invoke().bci());

            String qualifiedMethod = e.getClassName() + "." + e.getMethodName();

            if (!InfoLevelStructuredGraphDumpWhitelist.contains(qualifiedMethod)) {

                throw new VerificationError(

                                "In %s: call to %s with level == Debug.INFO_LEVEL not in %s.InfoLevelDumpWhitelist.%n", e, verifiedCallee.format("%H.%n(%p)"),

                                getClass().getName());

            }

        }

    }

    /**

     * Checks that a given call is not to {@link StringBuffer#toString()} or

     * {@link StringBuilder#toString()}.

     */

    private static void verifyStringConcat(StructuredGraph callerGraph, ResolvedJavaMethod verifiedCallee, int bci, int argIdx, int varArgsElementIndex, ResolvedJavaMethod callee) {

        if (callee.getDeclaringClass().getName().equals("Ljava/lang/StringBuilder;") || callee.getDeclaringClass().getName().equals("Ljava/lang/StringBuffer;")) {

            StackTraceElement e = callerGraph.method().asStackTraceElement(bci);

            if (varArgsElementIndex >= 0) {

                throw new VerificationError(

                                "In %s: element %d of parameter %d of call to %s appears to be a String concatenation expression.%n", e, varArgsElementIndex, argIdx,

                                verifiedCallee.format("%H.%n(%p)"));

            } else {

                throw new VerificationError(

                                "In %s: parameter %d of call to %s appears to be a String concatenation expression.", e, argIdx, verifiedCallee.format("%H.%n(%p)"));

            }

        }

    }

    /**

     * Checks that a given call is not to {@link Object#toString()}.

     */

    private static void verifyToStringCall(StructuredGraph callerGraph, ResolvedJavaMethod verifiedCallee, ResolvedJavaType stringType, ResolvedJavaMethod callee, int bci, int argIdx,

                    int varArgsElementIndex) {

        if (callee.getSignature().getParameterCount(false) == 0 && callee.getSignature().getReturnType(callee.getDeclaringClass()).equals(stringType)) {

            StackTraceElement e = callerGraph.method().asStackTraceElement(bci);

            if (varArgsElementIndex >= 0) {

                throw new VerificationError(

                                "In %s: element %d of parameter %d of call to %s is a call to toString() which is redundant (the callee will do it) and forces unnecessary eager evaluation.",

                                e, varArgsElementIndex, argIdx, verifiedCallee.format("%H.%n(%p)"));

            } else {

                throw new VerificationError("In %s: parameter %d of call to %s is a call to toString() which is redundant (the callee will do it) and forces unnecessary eager evaluation.", e, argIdx,

                                verifiedCallee.format("%H.%n(%p)"));

            }

        }

    }

    /**

     * Checks that a given call is not to {@link String#format(String, Object...)} or

     * {@link String#format(java.util.Locale, String, Object...)}.

     */

    private static void verifyFormatCall(StructuredGraph callerGraph, ResolvedJavaMethod verifiedCallee, ResolvedJavaType stringType, ResolvedJavaMethod callee, int bci, int argIdx,

                    int varArgsElementIndex) {

        if (callee.getDeclaringClass().equals(stringType) && callee.getSignature().getReturnType(callee.getDeclaringClass()).equals(stringType)) {

            StackTraceElement e = callerGraph.method().asStackTraceElement(bci);

            if (varArgsElementIndex >= 0) {

                throw new VerificationError(

                                "In %s: element %d of parameter %d of call to %s is a call to String.format() which is redundant (%s does formatting) and forces unnecessary eager evaluation.",

                                e, varArgsElementIndex, argIdx, verifiedCallee.format("%H.%n(%p)"), verifiedCallee.format("%h.%n"));

            } else {

                throw new VerificationError("In %s: parameter %d of call to %s is a call to String.format() which is redundant (%s does formatting) and forces unnecessary eager evaluation.", e,

                                argIdx,

                                verifiedCallee.format("%H.%n(%p)"), verifiedCallee.format("%h.%n"));

            }

        }

    }

}