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 * 2. Redistributions in binary form must reproduce the above copyright notice, this list of
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 * 3. Neither the name of the copyright holder nor the names of its contributors may be used to
 * endorse or promote products derived from this software without specific prior written
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package com.oracle.truffle.llvm.nodes.intrinsics.rust;

import com.oracle.truffle.api.CompilerAsserts;
import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
import com.oracle.truffle.api.dsl.Cached;
import com.oracle.truffle.api.dsl.NodeChild;
import com.oracle.truffle.api.dsl.Specialization;
import com.oracle.truffle.llvm.nodes.intrinsics.llvm.LLVMIntrinsic;
import com.oracle.truffle.llvm.runtime.LLVMExitException;
import com.oracle.truffle.llvm.runtime.datalayout.DataLayout;
import com.oracle.truffle.llvm.runtime.memory.LLVMMemory;
import com.oracle.truffle.llvm.runtime.nodes.api.LLVMExpressionNode;
import com.oracle.truffle.llvm.runtime.nodes.api.LLVMToNativeNode;
import com.oracle.truffle.llvm.runtime.pointer.LLVMNativePointer;
import com.oracle.truffle.llvm.runtime.pointer.LLVMPointer;
import com.oracle.truffle.llvm.runtime.types.PointerType;
import com.oracle.truffle.llvm.runtime.types.PrimitiveType;
import com.oracle.truffle.llvm.runtime.types.StructureType;
import com.oracle.truffle.llvm.runtime.types.Type;

@NodeChild(type = LLVMExpressionNode.class)
public abstract class LLVMPanic extends LLVMIntrinsic {

    protected PanicLocType createPanicLocation() {
        DataLayout dataSpecConverter = getContextReference().get().getDataSpecConverter();
        return PanicLocType.create(dataSpecConverter);
    }

    @Specialization
    protected Object doOp(LLVMPointer panicLocVar,
                    @Cached("createToNativeWithTarget()") LLVMToNativeNode toNative,
                    @Cached("createPanicLocation()") PanicLocType panicLoc,
                    @Cached("getLLVMMemory()") LLVMMemory memory) {
        LLVMNativePointer pointer = toNative.executeWithTarget(panicLocVar);
        throw panicLoc.read(memory, pointer.asNative());
    }

    static final class PanicLocType {
        private static final int EXIT_CODE_PANIC = 101;

        private final StrSliceType strslice;
        private final long offsetFilename;
        private final long offsetLineNr;

        private PanicLocType(DataLayout dataLayout, Type type, StrSliceType strslice) {
            this.strslice = strslice;
            StructureType structureType = (StructureType) ((PointerType) type).getElementType(0);
            this.offsetFilename = structureType.getOffsetOf(1, dataLayout);
            this.offsetLineNr = structureType.getOffsetOf(2, dataLayout);
        }

        @TruffleBoundary
        LLVMExitException read(LLVMMemory memory, long address) {
            String desc = strslice.read(memory, address);
            String filename = strslice.read(memory, address + offsetFilename);
            int linenr = memory.getI32(address + offsetLineNr);
            System.err.printf("thread '%s' panicked at '%s', %s:%d%n", Thread.currentThread().getName(), desc, filename, linenr);
            System.err.print("note: No backtrace available");
            return LLVMExitException.exit(EXIT_CODE_PANIC);
        }

        static PanicLocType create(DataLayout dataLayout) {
            CompilerAsserts.neverPartOfCompilation();
            StrSliceType strslice = StrSliceType.create(dataLayout);
            Type type = new PointerType((new StructureType(false, new Type[]{strslice.getType(), strslice.getType(), PrimitiveType.I32})));
            return new PanicLocType(dataLayout, type, strslice);
        }
    }

    private static final class StrSliceType {

        private final long lengthOffset;
        private final Type type;

        private StrSliceType(DataLayout dataLayout, Type type) {
            this.lengthOffset = ((StructureType) type).getOffsetOf(1, dataLayout);
            this.type = type;
        }

        @TruffleBoundary
        String read(LLVMMemory memory, long address) {
            long strAddr = memory.getPointer(address).asNative();
            int strLen = memory.getI32(address + lengthOffset);
            StringBuilder strBuilder = new StringBuilder();
            for (int i = 0; i < strLen; i++) {
                strBuilder.append((char) Byte.toUnsignedInt(memory.getI8(strAddr)));
                strAddr += Byte.BYTES;
            }
            return strBuilder.toString();
        }

        public Type getType() {
            return type;
        }

        static StrSliceType create(DataLayout dataLayout) {
            Type type = new StructureType(false, new Type[]{new PointerType(PrimitiveType.I8), PrimitiveType.I64});
            return new StrSliceType(dataLayout, type);
        }
    }
}
