--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/runtime/relocator.cpp Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,647 @@
+/*
+ * Copyright 1997-2005 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ */
+
+# include "incls/_precompiled.incl"
+# include "incls/_relocator.cpp.incl"
+
+#define MAX_METHOD_LENGTH 65535
+
+#define MAX_SHORT ((1 << 15) - 1)
+#define MIN_SHORT (- (1 << 15))
+
+// Encapsulates a code change request. There are 3 types.
+// General instruction, jump instruction, and table/lookup switches
+//
+class ChangeItem : public ResourceObj {
+ int _bci;
+ public:
+ ChangeItem(int bci) { _bci = bci; }
+ virtual bool handle_code_change(Relocator *r) = 0;
+
+ // type info
+ virtual bool is_widen() { return false; }
+ virtual bool is_jump_widen() { return false; }
+ virtual bool is_switch_pad() { return false; }
+
+ // accessors
+ int bci() { return _bci; }
+ void relocate(int break_bci, int delta) { if (_bci > break_bci) { _bci += delta; } }
+
+ virtual bool adjust(int bci, int delta) { return false; }
+
+ // debug
+ virtual void print() = 0;
+};
+
+class ChangeWiden : public ChangeItem {
+ int _new_ilen; // New length of instruction at bci
+ u_char* _inst_buffer; // New bytecodes
+ public:
+ ChangeWiden(int bci, int new_ilen, u_char* inst_buffer) : ChangeItem(bci) {
+ _new_ilen = new_ilen;
+ _inst_buffer = inst_buffer;
+ }
+
+ // Callback to do instruction
+ bool handle_code_change(Relocator *r) { return r->handle_widen(bci(), _new_ilen, _inst_buffer); };
+
+ bool is_widen() { return true; }
+
+ void print() { tty->print_cr("ChangeWiden. bci: %d New_ilen: %d", bci(), _new_ilen); }
+};
+
+class ChangeJumpWiden : public ChangeItem {
+ int _delta; // New length of instruction at bci
+ public:
+ ChangeJumpWiden(int bci, int delta) : ChangeItem(bci) { _delta = delta; }
+
+ // Callback to do instruction
+ bool handle_code_change(Relocator *r) { return r->handle_jump_widen(bci(), _delta); };
+
+ bool is_jump_widen() { return true; }
+
+ // If the bci matches, adjust the delta in the change jump request.
+ bool adjust(int jump_bci, int delta) {
+ if (bci() == jump_bci) {
+ if (_delta > 0)
+ _delta += delta;
+ else
+ _delta -= delta;
+ return true;
+ }
+ return false;
+ }
+
+ void print() { tty->print_cr("ChangeJumpWiden. bci: %d Delta: %d", bci(), _delta); }
+};
+
+class ChangeSwitchPad : public ChangeItem {
+ int _padding;
+ bool _is_lookup_switch;
+ public:
+ ChangeSwitchPad(int bci, int padding, bool is_lookup_switch) : ChangeItem(bci) {
+ _padding = padding;
+ _is_lookup_switch = is_lookup_switch;
+ }
+
+ // Callback to do instruction
+ bool handle_code_change(Relocator *r) { return r->handle_switch_pad(bci(), _padding, _is_lookup_switch); };
+
+ bool is_switch_pad() { return true; }
+ int padding() { return _padding; }
+ bool is_lookup_switch() { return _is_lookup_switch; }
+
+ void print() { tty->print_cr("ChangeSwitchPad. bci: %d Padding: %d IsLookupSwitch: %d", bci(), _padding, _is_lookup_switch); }
+};
+
+//-----------------------------------------------------------------------------------------------------------
+// Relocator code
+
+Relocator::Relocator(methodHandle m, RelocatorListener* listener) {
+ set_method(m);
+ set_code_length(method()->code_size());
+ set_code_array(NULL);
+ // Allocate code array and copy bytecodes
+ if (!expand_code_array(0)) {
+ // Should have at least MAX_METHOD_LENGTH available or the verifier
+ // would have failed.
+ ShouldNotReachHere();
+ }
+ set_compressed_line_number_table(NULL);
+ set_compressed_line_number_table_size(0);
+ _listener = listener;
+}
+
+// size is the new size of the instruction at bci. Hence, if size is less than the current
+// instruction sice, we will shrink the code.
+methodHandle Relocator::insert_space_at(int bci, int size, u_char inst_buffer[], TRAPS) {
+ _changes = new GrowableArray<ChangeItem*> (10);
+ _changes->push(new ChangeWiden(bci, size, inst_buffer));
+
+ if (TraceRelocator) {
+ tty->print_cr("Space at: %d Size: %d", bci, size);
+ _method->print();
+ _method->print_codes();
+ tty->print_cr("-------------------------------------------------");
+ }
+
+ if (!handle_code_changes()) return methodHandle();
+
+ // Construct the new method
+ methodHandle new_method = methodOopDesc::clone_with_new_data(method(),
+ code_array(), code_length(),
+ compressed_line_number_table(),
+ compressed_line_number_table_size(),
+ CHECK_(methodHandle()));
+ set_method(new_method);
+
+ if (TraceRelocator) {
+ tty->print_cr("-------------------------------------------------");
+ tty->print_cr("new method");
+ _method->print_codes();
+ }
+
+ return new_method;
+}
+
+
+bool Relocator::handle_code_changes() {
+ assert(_changes != NULL, "changes vector must be initialized");
+
+ while (!_changes->is_empty()) {
+ // Inv: everything is aligned.
+ ChangeItem* ci = _changes->first();
+
+ if (TraceRelocator) {
+ ci->print();
+ }
+
+ // Execute operation
+ if (!ci->handle_code_change(this)) return false;
+
+ // Shuffel items up
+ for (int index = 1; index < _changes->length(); index++) {
+ _changes->at_put(index-1, _changes->at(index));
+ }
+ _changes->pop();
+ }
+ return true;
+}
+
+
+bool Relocator::is_opcode_lookupswitch(Bytecodes::Code bc) {
+ switch (bc) {
+ case Bytecodes::_tableswitch: return false;
+ case Bytecodes::_lookupswitch: // not rewritten on ia64
+ case Bytecodes::_fast_linearswitch: // rewritten _lookupswitch
+ case Bytecodes::_fast_binaryswitch: return true; // rewritten _lookupswitch
+ default: ShouldNotReachHere();
+ }
+ return true; // dummy
+}
+
+// We need a special instruction size method, since lookupswitches and tableswitches might not be
+// properly alligned during relocation
+int Relocator::rc_instr_len(int bci) {
+ Bytecodes::Code bc= code_at(bci);
+ switch (bc) {
+ // In the case of switch instructions, see if we have the original
+ // padding recorded.
+ case Bytecodes::_tableswitch:
+ case Bytecodes::_lookupswitch:
+ case Bytecodes::_fast_linearswitch:
+ case Bytecodes::_fast_binaryswitch:
+ {
+ int pad = get_orig_switch_pad(bci, is_opcode_lookupswitch(bc));
+ if (pad == -1) {
+ return instruction_length_at(bci);
+ }
+ // Otherwise, depends on the switch type.
+ switch (bc) {
+ case Bytecodes::_tableswitch: {
+ int lo = int_at(bci + 1 + pad + 4 * 1);
+ int hi = int_at(bci + 1 + pad + 4 * 2);
+ int n = hi - lo + 1;
+ return 1 + pad + 4*(3 + n);
+ }
+ case Bytecodes::_lookupswitch:
+ case Bytecodes::_fast_linearswitch:
+ case Bytecodes::_fast_binaryswitch: {
+ int npairs = int_at(bci + 1 + pad + 4 * 1);
+ return 1 + pad + 4*(2 + 2*npairs);
+ }
+ default:
+ ShouldNotReachHere();
+ }
+ }
+ }
+ return instruction_length_at(bci);
+}
+
+// If a change item is recorded for "pc", with type "ct", returns the
+// associated padding, else -1.
+int Relocator::get_orig_switch_pad(int bci, bool is_lookup_switch) {
+ for (int k = 0; k < _changes->length(); k++) {
+ ChangeItem* ci = _changes->at(k);
+ if (ci->is_switch_pad()) {
+ ChangeSwitchPad* csp = (ChangeSwitchPad*)ci;
+ if (csp->is_lookup_switch() == is_lookup_switch && csp->bci() == bci) {
+ return csp->padding();
+ }
+ }
+ }
+ return -1;
+}
+
+
+// Push a ChangeJumpWiden if it doesn't already exist on the work queue,
+// otherwise adjust the item already there by delta. The calculation for
+// new_delta is wrong for this because it uses the offset stored in the
+// code stream itself which wasn't fixed when item was pushed on the work queue.
+void Relocator::push_jump_widen(int bci, int delta, int new_delta) {
+ for (int j = 0; j < _changes->length(); j++) {
+ ChangeItem* ci = _changes->at(j);
+ if (ci->adjust(bci, delta)) return;
+ }
+ _changes->push(new ChangeJumpWiden(bci, new_delta));
+}
+
+
+// The current instruction of "c" is a jump; one of its offset starts
+// at "offset" and is a short if "isShort" is "TRUE",
+// and an integer otherwise. If the jump crosses "breakPC", change
+// the span of the jump by "delta".
+void Relocator::change_jump(int bci, int offset, bool is_short, int break_bci, int delta) {
+ int bci_delta = (is_short) ? short_at(offset) : int_at(offset);
+ int targ = bci + bci_delta;
+
+ if ((bci <= break_bci && targ > break_bci) ||
+ (bci > break_bci && targ <= break_bci)) {
+ int new_delta;
+ if (bci_delta > 0)
+ new_delta = bci_delta + delta;
+ else
+ new_delta = bci_delta - delta;
+
+ if (is_short && ((new_delta > MAX_SHORT) || new_delta < MIN_SHORT)) {
+ push_jump_widen(bci, delta, new_delta);
+ } else if (is_short) {
+ short_at_put(offset, new_delta);
+ } else {
+ int_at_put(offset, new_delta);
+ }
+ }
+}
+
+
+// Changes all jumps crossing "break_bci" by "delta". May enqueue things
+// on "rc->changes"
+void Relocator::change_jumps(int break_bci, int delta) {
+ int bci = 0;
+ Bytecodes::Code bc;
+ // Now, adjust any affected instructions.
+ while (bci < code_length()) {
+ switch (bc= code_at(bci)) {
+ case Bytecodes::_ifeq:
+ case Bytecodes::_ifne:
+ case Bytecodes::_iflt:
+ case Bytecodes::_ifge:
+ case Bytecodes::_ifgt:
+ case Bytecodes::_ifle:
+ case Bytecodes::_if_icmpeq:
+ case Bytecodes::_if_icmpne:
+ case Bytecodes::_if_icmplt:
+ case Bytecodes::_if_icmpge:
+ case Bytecodes::_if_icmpgt:
+ case Bytecodes::_if_icmple:
+ case Bytecodes::_if_acmpeq:
+ case Bytecodes::_if_acmpne:
+ case Bytecodes::_ifnull:
+ case Bytecodes::_ifnonnull:
+ case Bytecodes::_goto:
+ case Bytecodes::_jsr:
+ change_jump(bci, bci+1, true, break_bci, delta);
+ break;
+ case Bytecodes::_goto_w:
+ case Bytecodes::_jsr_w:
+ change_jump(bci, bci+1, false, break_bci, delta);
+ break;
+ case Bytecodes::_tableswitch:
+ case Bytecodes::_lookupswitch:
+ case Bytecodes::_fast_linearswitch:
+ case Bytecodes::_fast_binaryswitch: {
+ int recPad = get_orig_switch_pad(bci, (bc != Bytecodes::_tableswitch));
+ int oldPad = (recPad != -1) ? recPad : align(bci+1) - (bci+1);
+ if (bci > break_bci) {
+ int new_bci = bci + delta;
+ int newPad = align(new_bci+1) - (new_bci+1);
+ // Do we need to check the padding?
+ if (newPad != oldPad) {
+ if (recPad == -1) {
+ _changes->push(new ChangeSwitchPad(bci, oldPad, (bc != Bytecodes::_tableswitch)));
+ }
+ }
+ }
+
+ // Then the rest, which depend on the kind of switch.
+ switch (bc) {
+ case Bytecodes::_tableswitch: {
+ change_jump(bci, bci +1 + oldPad, false, break_bci, delta);
+ // We cannot use the Bytecode_tableswitch abstraction, since the padding might not be correct.
+ int lo = int_at(bci + 1 + oldPad + 4 * 1);
+ int hi = int_at(bci + 1 + oldPad + 4 * 2);
+ int n = hi - lo + 1;
+ for (int k = 0; k < n; k++) {
+ change_jump(bci, bci +1 + oldPad + 4*(k+3), false, break_bci, delta);
+ }
+ // Special next-bci calculation here...
+ bci += 1 + oldPad + (n+3)*4;
+ continue;
+ }
+ case Bytecodes::_lookupswitch:
+ case Bytecodes::_fast_linearswitch:
+ case Bytecodes::_fast_binaryswitch: {
+ change_jump(bci, bci +1 + oldPad, false, break_bci, delta);
+ // We cannot use the Bytecode_lookupswitch abstraction, since the padding might not be correct.
+ int npairs = int_at(bci + 1 + oldPad + 4 * 1);
+ for (int k = 0; k < npairs; k++) {
+ change_jump(bci, bci + 1 + oldPad + 4*(2 + 2*k + 1), false, break_bci, delta);
+ }
+ /* Special next-bci calculation here... */
+ bci += 1 + oldPad + (2 + (npairs*2))*4;
+ continue;
+ }
+ default:
+ ShouldNotReachHere();
+ }
+ }
+ default:
+ break;
+ }
+ bci += rc_instr_len(bci);
+ }
+}
+
+// The width of instruction at "pc" is changing by "delta". Adjust the
+// exception table, if any, of "rc->mb".
+void Relocator::adjust_exception_table(int bci, int delta) {
+ typeArrayOop table = method()->exception_table();
+ for (int index = 0; index < table->length(); index +=4) {
+ if (table->int_at(index) > bci) {
+ table->int_at_put(index+0, table->int_at(index+0) + delta);
+ table->int_at_put(index+1, table->int_at(index+1) + delta);
+ } else if (bci < table->int_at(index+1)) {
+ table->int_at_put(index+1, table->int_at(index+1) + delta);
+ }
+ if (table->int_at(index+2) > bci)
+ table->int_at_put(index+2, table->int_at(index+2) + delta);
+ }
+}
+
+
+// The width of instruction at "bci" is changing by "delta". Adjust the line number table.
+void Relocator::adjust_line_no_table(int bci, int delta) {
+ if (method()->has_linenumber_table()) {
+ CompressedLineNumberReadStream reader(method()->compressed_linenumber_table());
+ CompressedLineNumberWriteStream writer(64); // plenty big for most line number tables
+ while (reader.read_pair()) {
+ int adjustment = (reader.bci() > bci) ? delta : 0;
+ writer.write_pair(reader.bci() + adjustment, reader.line());
+ }
+ writer.write_terminator();
+ set_compressed_line_number_table(writer.buffer());
+ set_compressed_line_number_table_size(writer.position());
+ }
+}
+
+
+// The width of instruction at "bci" is changing by "delta". Adjust the local variable table.
+void Relocator::adjust_local_var_table(int bci, int delta) {
+ int localvariable_table_length = method()->localvariable_table_length();
+ if (localvariable_table_length > 0) {
+ LocalVariableTableElement* table = method()->localvariable_table_start();
+ for (int i = 0; i < localvariable_table_length; i++) {
+ u2 current_bci = table[i].start_bci;
+ if (current_bci > bci) {
+ table[i].start_bci = current_bci + delta;
+ } else {
+ u2 current_length = table[i].length;
+ if (current_bci + current_length > bci) {
+ table[i].length = current_length + delta;
+ }
+ }
+ }
+ }
+}
+
+
+bool Relocator::expand_code_array(int delta) {
+ int length = MAX2(code_length() + delta, code_length() * (100+code_slop_pct()) / 100);
+
+ if (length > MAX_METHOD_LENGTH) {
+ if (delta == 0 && code_length() <= MAX_METHOD_LENGTH) {
+ length = MAX_METHOD_LENGTH;
+ } else {
+ return false;
+ }
+ }
+
+ unsigned char* new_code_array = NEW_RESOURCE_ARRAY(unsigned char, length);
+ if (!new_code_array) return false;
+
+ // Expanding current array
+ if (code_array() != NULL) {
+ memcpy(new_code_array, code_array(), code_length());
+ } else {
+ // Initial copy. Copy directly from methodOop
+ memcpy(new_code_array, method()->code_base(), code_length());
+ }
+
+ set_code_array(new_code_array);
+ set_code_array_length(length);
+
+ return true;
+}
+
+
+// The instruction at "bci", whose size is "ilen", is changing size by
+// "delta". Reallocate, move code, recalculate jumps, and enqueue
+// change items as necessary.
+bool Relocator::relocate_code(int bci, int ilen, int delta) {
+ int next_bci = bci + ilen;
+ if (delta > 0 && code_length() + delta > code_array_length()) {
+ // Expand allocated code space, if necessary.
+ if (!expand_code_array(delta)) {
+ return false;
+ }
+ }
+
+ // We require 4-byte alignment of code arrays.
+ assert(((intptr_t)code_array() & 3) == 0, "check code alignment");
+ // Change jumps before doing the copying; this routine requires aligned switches.
+ change_jumps(bci, delta);
+
+ // In case we have shrunken a tableswitch/lookupswitch statement, we store the last
+ // bytes that get overwritten. We have to copy the bytes after the change_jumps method
+ // has been called, since it is likly to update last offset in a tableswitch/lookupswitch
+ if (delta < 0) {
+ assert(delta>=-3, "we cannot overwrite more than 3 bytes");
+ memcpy(_overwrite, addr_at(bci + ilen + delta), -delta);
+ }
+
+ memmove(addr_at(next_bci + delta), addr_at(next_bci), code_length() - next_bci);
+ set_code_length(code_length() + delta);
+ // Also adjust exception tables...
+ adjust_exception_table(bci, delta);
+ // Line number tables...
+ adjust_line_no_table(bci, delta);
+ // And local variable table...
+ adjust_local_var_table(bci, delta);
+
+ // Relocate the pending change stack...
+ for (int j = 0; j < _changes->length(); j++) {
+ ChangeItem* ci = _changes->at(j);
+ ci->relocate(bci, delta);
+ }
+
+ // Notify any listeners about code relocation
+ notify(bci, delta, code_length());
+
+ return true;
+}
+
+// relocate a general instruction. Called by ChangeWiden class
+bool Relocator::handle_widen(int bci, int new_ilen, u_char inst_buffer[]) {
+ int ilen = rc_instr_len(bci);
+ if (!relocate_code(bci, ilen, new_ilen - ilen))
+ return false;
+
+ // Insert new bytecode(s)
+ for(int k = 0; k < new_ilen; k++) {
+ code_at_put(bci + k, (Bytecodes::Code)inst_buffer[k]);
+ }
+
+ return true;
+}
+
+// handle jump_widen instruction. Called be ChangeJumpWiden class
+bool Relocator::handle_jump_widen(int bci, int delta) {
+ int ilen = rc_instr_len(bci);
+
+ Bytecodes::Code bc = code_at(bci);
+ switch (bc) {
+ case Bytecodes::_ifeq:
+ case Bytecodes::_ifne:
+ case Bytecodes::_iflt:
+ case Bytecodes::_ifge:
+ case Bytecodes::_ifgt:
+ case Bytecodes::_ifle:
+ case Bytecodes::_if_icmpeq:
+ case Bytecodes::_if_icmpne:
+ case Bytecodes::_if_icmplt:
+ case Bytecodes::_if_icmpge:
+ case Bytecodes::_if_icmpgt:
+ case Bytecodes::_if_icmple:
+ case Bytecodes::_if_acmpeq:
+ case Bytecodes::_if_acmpne:
+ case Bytecodes::_ifnull:
+ case Bytecodes::_ifnonnull: {
+ const int goto_length = Bytecodes::length_for(Bytecodes::_goto);
+
+ // If 'if' points to the next bytecode after goto, it's already handled.
+ // it shouldn't be.
+ assert (short_at(bci+1) != ilen+goto_length, "if relocation already handled");
+ assert(ilen == 3, "check length");
+
+ // Convert to 0 if <cond> goto 6
+ // 3 _goto 11
+ // 6 _goto_w <wide delta offset>
+ // 11 <else code>
+ const int goto_w_length = Bytecodes::length_for(Bytecodes::_goto_w);
+ const int add_bci = goto_length + goto_w_length;
+
+ if (!relocate_code(bci, 3, /*delta*/add_bci)) return false;
+
+ // if bytecode points to goto_w instruction
+ short_at_put(bci + 1, ilen + goto_length);
+
+ int cbci = bci + ilen;
+ // goto around
+ code_at_put(cbci, Bytecodes::_goto);
+ short_at_put(cbci + 1, add_bci);
+ // goto_w <wide delta>
+ cbci = cbci + goto_length;
+ code_at_put(cbci, Bytecodes::_goto_w);
+ if (delta > 0) {
+ delta += 2; // goto_w is 2 bytes more than "if" code
+ } else {
+ delta -= ilen+goto_length; // branch starts at goto_w offset
+ }
+ int_at_put(cbci + 1, delta);
+ break;
+
+ }
+ case Bytecodes::_goto:
+ case Bytecodes::_jsr:
+ assert(ilen == 3, "check length");
+
+ if (!relocate_code(bci, 3, 2)) return false;
+ if (bc == Bytecodes::_goto)
+ code_at_put(bci, Bytecodes::_goto_w);
+ else
+ code_at_put(bci, Bytecodes::_jsr_w);
+
+ // If it's a forward jump, add 2 for the widening.
+ if (delta > 0) delta += 2;
+ int_at_put(bci + 1, delta);
+ break;
+
+ default: ShouldNotReachHere();
+ }
+
+ return true;
+}
+
+// handle lookup/table switch instructions. Called be ChangeSwitchPad class
+bool Relocator::handle_switch_pad(int bci, int old_pad, bool is_lookup_switch) {
+ int ilen = rc_instr_len(bci);
+ int new_pad = align(bci+1) - (bci+1);
+ int pad_delta = new_pad - old_pad;
+ if (pad_delta != 0) {
+ int len;
+ if (!is_lookup_switch) {
+ int low = int_at(bci+1+old_pad+4);
+ int high = int_at(bci+1+old_pad+8);
+ len = high-low+1 + 3; // 3 for default, hi, lo.
+ } else {
+ int npairs = int_at(bci+1+old_pad+4);
+ len = npairs*2 + 2; // 2 for default, npairs.
+ }
+ // Because "relocateCode" does a "changeJumps" loop,
+ // which parses instructions to determine their length,
+ // we need to call that before messing with the current
+ // instruction. Since it may also overwrite the current
+ // instruction when moving down, remember the possibly
+ // overwritten part.
+
+ // Move the code following the instruction...
+ if (!relocate_code(bci, ilen, pad_delta)) return false;
+
+ if (pad_delta < 0) {
+ // Move the shrunken instruction down.
+ memmove(addr_at(bci + 1 + new_pad),
+ addr_at(bci + 1 + old_pad),
+ len * 4 + pad_delta);
+ memmove(addr_at(bci + 1 + new_pad + len*4 + pad_delta),
+ _overwrite, -pad_delta);
+ } else {
+ assert(pad_delta > 0, "check");
+ // Move the expanded instruction up.
+ memmove(addr_at(bci +1 + new_pad),
+ addr_at(bci +1 + old_pad),
+ len * 4);
+ }
+ }
+ return true;
+}