public ByteCodeRewriter(Method method, ConstantPool cpool, byte[] code) {
this.method = method;
this.cpool = cpool;
this.cpCache = cpool.getCache();
this.code = code;
this.bytes = VM.getVM().getBytes();
}
static {
VM.registerVMInitializedObserver(
new Observer() {
public void update(Observable o, Object data) {
initialize(VM.getVM().getTypeDataBase());
}
});
}
private static synchronized void initialize(TypeDataBase db) throws WrongTypeException {
Type type = db.lookupType("methodOopDesc");
constMethod = new OopField(type.getOopField("_constMethod"), 0);
constants = new OopField(type.getOopField("_constants"), 0);
methodSize = new CIntField(type.getCIntegerField("_method_size"), 0);
maxStack = new CIntField(type.getCIntegerField("_max_stack"), 0);
maxLocals = new CIntField(type.getCIntegerField("_max_locals"), 0);
sizeOfParameters = new CIntField(type.getCIntegerField("_size_of_parameters"), 0);
accessFlags = new CIntField(type.getCIntegerField("_access_flags"), 0);
code = type.getAddressField("_code");
vtableIndex = new CIntField(type.getCIntegerField("_vtable_index"), 0);
if (!VM.getVM().isCore()) {
invocationCounter = new CIntField(type.getCIntegerField("_invocation_counter"), 0);
}
bytecodeOffset = type.getSize();
/*
interpreterEntry = type.getAddressField("_interpreter_entry");
fromCompiledCodeEntryPoint = type.getAddressField("_from_compiled_code_entry_point");
*/
objectInitializerName = null;
classInitializerName = null;
}
/** Returns false if not able to find a frame within a reasonable range. */
public boolean run(long regionInBytesToSearch) {
Address sp = context.getRegisterAsAddress(AMD64ThreadContext.RSP);
Address pc = context.getRegisterAsAddress(AMD64ThreadContext.RIP);
Address fp = context.getRegisterAsAddress(AMD64ThreadContext.RBP);
if (sp == null) {
// Bail out if no last java frame either
if (thread.getLastJavaSP() != null) {
setValues(thread.getLastJavaSP(), thread.getLastJavaFP(), null);
return true;
}
return false;
}
Address end = sp.addOffsetTo(regionInBytesToSearch);
VM vm = VM.getVM();
setValues(null, null, null); // Assume we're not going to find anything
if (vm.isJavaPCDbg(pc)) {
if (vm.isClientCompiler()) {
// If the topmost frame is a Java frame, we are (pretty much)
// guaranteed to have a viable EBP. We should be more robust
// than this (we have the potential for losing entire threads'
// stack traces) but need to see how much work we really have
// to do here. Searching the stack for an (SP, FP) pair is
// hard since it's easy to misinterpret inter-frame stack
// pointers as base-of-frame pointers; we also don't know the
// sizes of C1 frames (not registered in the nmethod) so can't
// derive them from ESP.
setValues(sp, fp, pc);
return true;
} else {
if (vm.getInterpreter().contains(pc)) {
if (DEBUG) {
System.out.println(
"CurrentFrameGuess: choosing interpreter frame: sp = "
+ sp
+ ", fp = "
+ fp
+ ", pc = "
+ pc);
}
setValues(sp, fp, pc);
return true;
}
// For the server compiler, EBP is not guaranteed to be valid
// for compiled code. In addition, an earlier attempt at a
// non-searching algorithm (see below) failed because the
// stack pointer from the thread context was pointing
// (considerably) beyond the ostensible end of the stack, into
// garbage; walking from the topmost frame back caused a crash.
//
// This algorithm takes the current PC as a given and tries to
// find the correct corresponding SP by walking up the stack
// and repeatedly performing stackwalks (very inefficient).
//
// FIXME: there is something wrong with stackwalking across
// adapter frames...this is likely to be the root cause of the
// failure with the simpler algorithm below.
for (long offset = 0; offset < regionInBytesToSearch; offset += vm.getAddressSize()) {
try {
Address curSP = sp.addOffsetTo(offset);
Frame frame = new X86Frame(curSP, null, pc);
RegisterMap map = thread.newRegisterMap(false);
while (frame != null) {
if (frame.isEntryFrame() && frame.entryFrameIsFirst()) {
// We were able to traverse all the way to the
// bottommost Java frame.
// This sp looks good. Keep it.
if (DEBUG) {
System.out.println("CurrentFrameGuess: Choosing sp = " + curSP + ", pc = " + pc);
}
setValues(curSP, null, pc);
return true;
}
frame = frame.sender(map);
}
} catch (Exception e) {
if (DEBUG) {
System.out.println("CurrentFrameGuess: Exception " + e + " at offset " + offset);
}
// Bad SP. Try another.
}
}
// Were not able to find a plausible SP to go with this PC.
// Bail out.
return false;
/*
// Original algorithm which does not work because SP was
// pointing beyond where it should have:
// For the server compiler, EBP is not guaranteed to be valid
// for compiled code. We see whether the PC is in the
// interpreter and take care of that, otherwise we run code
// (unfortunately) duplicated from AMD64Frame.senderForCompiledFrame.
CodeCache cc = vm.getCodeCache();
if (cc.contains(pc)) {
CodeBlob cb = cc.findBlob(pc);
// See if we can derive a frame pointer from SP and PC
// NOTE: This is the code duplicated from AMD64Frame
Address saved_fp = null;
int llink_offset = cb.getLinkOffset();
if (llink_offset >= 0) {
// Restore base-pointer, since next frame might be an interpreter frame.
Address fp_addr = sp.addOffsetTo(VM.getVM().getAddressSize() * llink_offset);
saved_fp = fp_addr.getAddressAt(0);
}
setValues(sp, saved_fp, pc);
return true;
}
*/
}
} else {
// If the current program counter was not known to us as a Java
// PC, we currently assume that we are in the run-time system
// and attempt to look to thread-local storage for saved ESP and
// EBP. Note that if these are null (because we were, in fact,
// in Java code, i.e., vtable stubs or similar, and the SA
// didn't have enough insight into the target VM to understand
// that) then we are going to lose the entire stack trace for
// the thread, which is sub-optimal. FIXME.
if (DEBUG) {
System.out.println(
"CurrentFrameGuess: choosing last Java frame: sp = "
+ thread.getLastJavaSP()
+ ", fp = "
+ thread.getLastJavaFP());
}
if (thread.getLastJavaSP() == null) {
return false; // No known Java frames on stack
}
setValues(thread.getLastJavaSP(), thread.getLastJavaFP(), null);
return true;
}
}
public long getInvocationCounter() {
if (Assert.ASSERTS_ENABLED) {
Assert.that(!VM.getVM().isCore(), "must not be used in core build");
}
return invocationCounter.getValue(this);
}
private static Symbol classInitializerName() {
if (classInitializerName == null) {
classInitializerName = VM.getVM().getSymbolTable().probe("<clinit>");
}
return classInitializerName;
}
private static Symbol objectInitializerName() {
if (objectInitializerName == null) {
objectInitializerName = VM.getVM().getSymbolTable().probe("<init>");
}
return objectInitializerName;
}
