Examples with Offset org.vmmagic.unboxed.Offset used on opensource projects

Example 86 with Offset

use of org.vmmagic.unboxed.Offset in project JikesRVM by JikesRVM.

the class GenerateInterfaceDeclarations method emitCDeclarationsForJavaType.

static void emitCDeclarationsForJavaType(String Cname, RVMClass cls) {
    // How many instance fields are there?
    // 
    RVMField[] allFields = cls.getDeclaredFields();
    int fieldCount = 0;
    for (RVMField field : allFields) {
        if (!field.isStatic()) {
            fieldCount++;
        }
    }
    RVMField[] fields = new RVMField[fieldCount];
    for (int i = 0, j = 0; i < allFields.length; i++) {
        if (!allFields[i].isStatic()) {
            fields[j++] = allFields[i];
        }
    }
    Arrays.sort(fields, new AscendingOffsetComparator());
    // Emit field declarations
    // 
    pln("struct " + Cname + " {");
    // Set up cursor - scalars will waste 4 bytes on 64-bit arch
    // 
    boolean needsAlign = VM.BuildFor64Addr;
    int addrSize = VM.BuildFor32Addr ? 4 : 8;
    // Header Space for objects
    int startOffset = ObjectModel.objectStartOffset(cls);
    Offset current = Offset.fromIntSignExtend(startOffset);
    for (int i = 0; current.sLT(fields[0].getOffset()); i++) {
        pln("  uint32_t    headerPadding" + i + ";");
        current = current.plus(4);
    }
    for (int i = 0; i < fields.length; i++) {
        RVMField field = fields[i];
        TypeReference t = field.getType();
        Offset offset = field.getOffset();
        String name = field.getName().toString();
        // Align by blowing 4 bytes if needed
        if (needsAlign && current.plus(4).EQ(offset)) {
            pln("  uint32_t    padding" + i + ";");
            current = current.plus(4);
        }
        if (!current.EQ(offset)) {
            System.err.printf("current (%s) and offset (%s) are neither identical nor differ by 4", unboxedValueString(current), unboxedValueString(offset));
            System.exit(1);
        }
        if (t.isIntType()) {
            current = current.plus(4);
            pln("   uint32_t " + name + ";");
        } else if (t.isLongType()) {
            current = current.plus(8);
            pln("   uint64_t " + name + ";");
        } else if (t.isWordLikeType()) {
            pln("   Address " + name + ";");
            current = current.plus(addrSize);
        } else if (t.isArrayType() && t.getArrayElementType().isWordLikeType()) {
            pln("   Address * " + name + ";");
            current = current.plus(addrSize);
        } else if (t.isArrayType() && t.getArrayElementType().isIntType()) {
            pln("   unsigned int * " + name + ";");
            current = current.plus(addrSize);
        } else if (t.isReferenceType()) {
            pln("   Address " + name + ";");
            current = current.plus(addrSize);
        } else {
            System.err.println("Unexpected field " + name + " with type " + t);
            throw new RuntimeException("unexpected field type");
        }
    }
    pln("};");
}

Example 87 with Offset

use of org.vmmagic.unboxed.Offset in project JikesRVM by JikesRVM.

the class SpinLock method lock.

/**
 * Acquire a lock.
 */
public void lock() {
    if (!VM.runningVM)
        return;
    VM.disableYieldpoints();
    RVMThread i = RVMThread.getCurrentThread();
    RVMThread p;
    int attempts = 0;
    Offset latestContenderOffset = Entrypoints.latestContenderField.getOffset();
    do {
        p = Magic.objectAsThread(Magic.addressAsObject(Magic.prepareAddress(this, latestContenderOffset)));
        if (p == null) {
            // nobody owns the lock
            if (Magic.attemptAddress(this, latestContenderOffset, Address.zero(), Magic.objectAsAddress(i))) {
                if (!VM.MagicAttemptImpliesStoreLoadBarrier)
                    Magic.fence();
                return;
            } else {
                // don't handle contention
                continue;
            }
        } else if (MCS_Locking && Magic.objectAsAddress(p).NE(IN_FLUX)) {
            // lock is owned, but not being changed
            if (Magic.attemptAddress(this, latestContenderOffset, Magic.objectAsAddress(p), IN_FLUX)) {
                if (!VM.MagicAttemptImpliesStoreLoadBarrier)
                    Magic.fence();
                break;
            }
        }
        handleMicrocontention(attempts++);
    } while (true);
    // i owns the lock
    if (VM.VerifyAssertions && !MCS_Locking)
        VM._assert(VM.NOT_REACHED);
    i.awaitingSpinLock = this;
    if (p.awaitingSpinLock != this) {
        // make i first (and only) waiter on the contender chain
        i.contenderLink = i;
    } else {
        // make i last waiter on the contender chain
        i.contenderLink = p.contenderLink;
        p.contenderLink = i;
    }
    // so other contender will see updated contender chain
    Magic.fence();
    // other threads can get at the lock
    Magic.setObjectAtOffset(this, latestContenderOffset, i);
    do {
        // spin, waiting for the lock
        // to make new value visible as soon as possible
        Magic.combinedLoadBarrier();
    } while (i.awaitingSpinLock == this);
}

Example 88 with Offset

use of org.vmmagic.unboxed.Offset in project JikesRVM by JikesRVM.

the class SpinLock method tryLock.

/**
 * Conditionally acquire a lock.
 * @return whether acquisition succeeded
 */
public boolean tryLock() {
    if (!VM.runningVM)
        return true;
    VM.disableYieldpoints();
    Offset latestContenderOffset = Entrypoints.latestContenderField.getOffset();
    if (Magic.prepareAddress(this, latestContenderOffset).isZero()) {
        Address cp = Magic.objectAsAddress(RVMThread.getCurrentThread());
        if (Magic.attemptAddress(this, latestContenderOffset, Address.zero(), cp)) {
            if (!VM.MagicAttemptImpliesStoreLoadBarrier)
                Magic.fence();
            return true;
        }
    }
    VM.enableYieldpoints();
    return false;
}

Example 89 with Offset

use of org.vmmagic.unboxed.Offset in project JikesRVM by JikesRVM.

the class SpinLock method unlock.

/**
 * Release a lock.
 */
public void unlock() {
    if (!VM.runningVM)
        return;
    // commit changes while lock was held so they are visible to the next processor that acquires the lock
    Magic.fence();
    Offset latestContenderOffset = Entrypoints.latestContenderField.getOffset();
    RVMThread i = RVMThread.getCurrentThread();
    if (!MCS_Locking) {
        // latestContender = null;
        Magic.setObjectAtOffset(this, latestContenderOffset, null);
        VM.enableYieldpoints();
        return;
    }
    RVMThread p;
    do {
        p = Magic.objectAsThread(Magic.addressAsObject(Magic.prepareAddress(this, latestContenderOffset)));
        if (p == i) {
            // nobody is waiting for the lock
            if (Magic.attemptAddress(this, latestContenderOffset, Magic.objectAsAddress(p), Address.zero())) {
                break;
            }
        } else if (Magic.objectAsAddress(p).NE(IN_FLUX)) {
            // there are waiters, but the contention chain is not being changed
            if (Magic.attemptAddress(this, latestContenderOffset, Magic.objectAsAddress(p), IN_FLUX)) {
                break;
            }
        } else {
            // in flux
            // wait a little before trying again
            handleMicrocontention(-1);
        }
    } while (true);
    if (p != i) {
        // p is the last thread on the chain of threads contending for the lock
        // q is first thread on the chain
        RVMThread q = p.contenderLink;
        if (p == q) {
            // only one thread waiting for the lock
            // q now owns the lock
            q.awaitingSpinLock = null;
            // make sure the chain of waiting threads gets updated before another thread accesses the chain
            Magic.fence();
            // other contenders can get at the lock:
            // latestContender = q;
            Magic.setObjectAtOffset(this, latestContenderOffset, q);
        } else {
            // more than one thread waiting for the lock
            // remove q from the chain
            p.contenderLink = q.contenderLink;
            // q now owns the lock
            q.awaitingSpinLock = null;
            // make sure the chain of waiting threads gets updated before another thread accesses the chain
            Magic.fence();
            // other contenders can get at the lock
            Magic.setObjectAtOffset(this, latestContenderOffset, p);
        }
    }
    VM.enableYieldpoints();
}

Example 90 with Offset

use of org.vmmagic.unboxed.Offset in project JikesRVM by JikesRVM.

the class DynamicLibrary method load.

/**
 * Load a dynamic library
 * @param libName the name of the library to load.
 * @return 0 on failure, 1 on success
 */
public static synchronized int load(String libName) {
    DynamicLibrary dl = dynamicLibraries.get(libName);
    if (dl != null) {
        // success: already loaded
        return 1;
    } else {
        // Convert file name from unicode to filesystem character set.
        // (Assume file name is ASCII, for now).
        // 
        byte[] asciiName = StringUtilities.stringToBytesNullTerminated(libName);
        // make sure we have enough stack to load the library.
        // This operation has been known to require more than 20K of stack.
        RVMThread myThread = RVMThread.getCurrentThread();
        Offset remaining = Magic.getFramePointer().diff(myThread.stackLimit);
        int stackNeededInBytes = StackFrameLayout.getStackSizeDLOpen() - remaining.toInt();
        if (stackNeededInBytes > 0) {
            if (myThread.hasNativeStackFrame()) {
                throw new java.lang.StackOverflowError("Not enough space to open shared library");
            } else {
                RVMThread.resizeCurrentStack(myThread.getStackLength() + stackNeededInBytes, null);
            }
        }
        Address libHandler = SysCall.sysCall.sysDlopen(asciiName);
        if (!libHandler.isZero()) {
            dynamicLibraries.put(libName, new DynamicLibrary(libName, libHandler));
            return 1;
        } else {
            // fail; file does not exist
            return 0;
        }
    }
}