--- a/hotspot/src/share/vm/c1/c1_LinearScan.cpp Mon Nov 04 10:44:46 2013 +0100
+++ b/hotspot/src/share/vm/c1/c1_LinearScan.cpp Tue Nov 05 02:29:41 2013 -0800
@@ -1138,8 +1138,10 @@
}
}
}
-
- } else if (opr_type != T_LONG) {
+ // We want to sometimes use logical operations on pointers, in particular in GC barriers.
+ // Since 64bit logical operations do not current support operands on stack, we have to make sure
+ // T_OBJECT doesn't get spilled along with T_LONG.
+ } else if (opr_type != T_LONG LP64_ONLY(&& opr_type != T_OBJECT)) {
// integer instruction (note: long operands must always be in register)
switch (op->code()) {
case lir_cmp:
--- a/hotspot/src/share/vm/opto/compile.cpp Mon Nov 04 10:44:46 2013 +0100
+++ b/hotspot/src/share/vm/opto/compile.cpp Tue Nov 05 02:29:41 2013 -0800
@@ -848,6 +848,7 @@
}
#endif
+ NOT_PRODUCT( verify_barriers(); )
// Now that we know the size of all the monitors we can add a fixed slot
// for the original deopt pc.
@@ -3373,6 +3374,72 @@
}
}
}
+
+// Verify GC barriers consistency
+// Currently supported:
+// - G1 pre-barriers (see GraphKit::g1_write_barrier_pre())
+void Compile::verify_barriers() {
+ if (UseG1GC) {
+ // Verify G1 pre-barriers
+ const int marking_offset = in_bytes(JavaThread::satb_mark_queue_offset() + PtrQueue::byte_offset_of_active());
+
+ ResourceArea *area = Thread::current()->resource_area();
+ Unique_Node_List visited(area);
+ Node_List worklist(area);
+ // We're going to walk control flow backwards starting from the Root
+ worklist.push(_root);
+ while (worklist.size() > 0) {
+ Node* x = worklist.pop();
+ if (x == NULL || x == top()) continue;
+ if (visited.member(x)) {
+ continue;
+ } else {
+ visited.push(x);
+ }
+
+ if (x->is_Region()) {
+ for (uint i = 1; i < x->req(); i++) {
+ worklist.push(x->in(i));
+ }
+ } else {
+ worklist.push(x->in(0));
+ // We are looking for the pattern:
+ // /->ThreadLocal
+ // If->Bool->CmpI->LoadB->AddP->ConL(marking_offset)
+ // \->ConI(0)
+ // We want to verify that the If and the LoadB have the same control
+ // See GraphKit::g1_write_barrier_pre()
+ if (x->is_If()) {
+ IfNode *iff = x->as_If();
+ if (iff->in(1)->is_Bool() && iff->in(1)->in(1)->is_Cmp()) {
+ CmpNode *cmp = iff->in(1)->in(1)->as_Cmp();
+ if (cmp->Opcode() == Op_CmpI && cmp->in(2)->is_Con() && cmp->in(2)->bottom_type()->is_int()->get_con() == 0
+ && cmp->in(1)->is_Load()) {
+ LoadNode* load = cmp->in(1)->as_Load();
+ if (load->Opcode() == Op_LoadB && load->in(2)->is_AddP() && load->in(2)->in(2)->Opcode() == Op_ThreadLocal
+ && load->in(2)->in(3)->is_Con()
+ && load->in(2)->in(3)->bottom_type()->is_intptr_t()->get_con() == marking_offset) {
+
+ Node* if_ctrl = iff->in(0);
+ Node* load_ctrl = load->in(0);
+
+ if (if_ctrl != load_ctrl) {
+ // Skip possible CProj->NeverBranch in infinite loops
+ if ((if_ctrl->is_Proj() && if_ctrl->Opcode() == Op_CProj)
+ && (if_ctrl->in(0)->is_MultiBranch() && if_ctrl->in(0)->Opcode() == Op_NeverBranch)) {
+ if_ctrl = if_ctrl->in(0)->in(0);
+ }
+ }
+ assert(load_ctrl != NULL && if_ctrl == load_ctrl, "controls must match");
+ }
+ }
+ }
+ }
+ }
+ }
+ }
+}
+
#endif
// The Compile object keeps track of failure reasons separately from the ciEnv.
--- a/hotspot/src/share/vm/opto/compile.hpp Mon Nov 04 10:44:46 2013 +0100
+++ b/hotspot/src/share/vm/opto/compile.hpp Tue Nov 05 02:29:41 2013 -0800
@@ -1148,6 +1148,9 @@
// graph is strongly connected from root in both directions.
void verify_graph_edges(bool no_dead_code = false) PRODUCT_RETURN;
+ // Verify GC barrier patterns
+ void verify_barriers() PRODUCT_RETURN;
+
// End-of-run dumps.
static void print_statistics() PRODUCT_RETURN;
--- a/hotspot/src/share/vm/opto/loopTransform.cpp Mon Nov 04 10:44:46 2013 +0100
+++ b/hotspot/src/share/vm/opto/loopTransform.cpp Tue Nov 05 02:29:41 2013 -0800
@@ -1964,7 +1964,7 @@
// Find loads off the surviving projection; remove their control edge
for (DUIterator_Fast imax, i = dp->fast_outs(imax); i < imax; i++) {
Node* cd = dp->fast_out(i); // Control-dependent node
- if( cd->is_Load() ) { // Loads can now float around in the loop
+ if (cd->is_Load() && cd->depends_only_on_test()) { // Loads can now float around in the loop
// Allow the load to float around in the loop, or before it
// but NOT before the pre-loop.
_igvn.replace_input_of(cd, 0, ctrl); // ctrl, not NULL
--- a/hotspot/src/share/vm/opto/memnode.hpp Mon Nov 04 10:44:46 2013 +0100
+++ b/hotspot/src/share/vm/opto/memnode.hpp Tue Nov 05 02:29:41 2013 -0800
@@ -204,6 +204,17 @@
protected:
const Type* load_array_final_field(const TypeKlassPtr *tkls,
ciKlass* klass) const;
+ // depends_only_on_test is almost always true, and needs to be almost always
+ // true to enable key hoisting & commoning optimizations. However, for the
+ // special case of RawPtr loads from TLS top & end, and other loads performed by
+ // GC barriers, the control edge carries the dependence preventing hoisting past
+ // a Safepoint instead of the memory edge. (An unfortunate consequence of having
+ // Safepoints not set Raw Memory; itself an unfortunate consequence of having Nodes
+ // which produce results (new raw memory state) inside of loops preventing all
+ // manner of other optimizations). Basically, it's ugly but so is the alternative.
+ // See comment in macro.cpp, around line 125 expand_allocate_common().
+ virtual bool depends_only_on_test() const { return adr_type() != TypeRawPtr::BOTTOM; }
+
};
//------------------------------LoadBNode--------------------------------------
@@ -370,16 +381,6 @@
virtual uint ideal_reg() const { return Op_RegP; }
virtual int store_Opcode() const { return Op_StoreP; }
virtual BasicType memory_type() const { return T_ADDRESS; }
- // depends_only_on_test is almost always true, and needs to be almost always
- // true to enable key hoisting & commoning optimizations. However, for the
- // special case of RawPtr loads from TLS top & end, the control edge carries
- // the dependence preventing hoisting past a Safepoint instead of the memory
- // edge. (An unfortunate consequence of having Safepoints not set Raw
- // Memory; itself an unfortunate consequence of having Nodes which produce
- // results (new raw memory state) inside of loops preventing all manner of
- // other optimizations). Basically, it's ugly but so is the alternative.
- // See comment in macro.cpp, around line 125 expand_allocate_common().
- virtual bool depends_only_on_test() const { return adr_type() != TypeRawPtr::BOTTOM; }
};
@@ -393,16 +394,6 @@
virtual uint ideal_reg() const { return Op_RegN; }
virtual int store_Opcode() const { return Op_StoreN; }
virtual BasicType memory_type() const { return T_NARROWOOP; }
- // depends_only_on_test is almost always true, and needs to be almost always
- // true to enable key hoisting & commoning optimizations. However, for the
- // special case of RawPtr loads from TLS top & end, the control edge carries
- // the dependence preventing hoisting past a Safepoint instead of the memory
- // edge. (An unfortunate consequence of having Safepoints not set Raw
- // Memory; itself an unfortunate consequence of having Nodes which produce
- // results (new raw memory state) inside of loops preventing all manner of
- // other optimizations). Basically, it's ugly but so is the alternative.
- // See comment in macro.cpp, around line 125 expand_allocate_common().
- virtual bool depends_only_on_test() const { return adr_type() != TypeRawPtr::BOTTOM; }
};
//------------------------------LoadKlassNode----------------------------------
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/test/compiler/regalloc/C1ObjectSpillInLogicOp.java Tue Nov 05 02:29:41 2013 -0800
@@ -0,0 +1,45 @@
+/*
+ * 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.
+ */
+
+/*
+ * @test
+ * @bug 8027751
+ * @summary C1 crashes generating G1 post-barrier in Unsafe.getAndSetObject() intrinsic because of the new value spill
+ * @run main/othervm -XX:+UseG1GC C1ObjectSpillInLogicOp
+ *
+ * G1 barriers use logical operators (xor) on T_OBJECT mixed with T_LONG or T_INT.
+ * The current implementation of logical operations on x86 in C1 doesn't allow for long operands to be on stack.
+ * There is a special code in the register allocator that forces long arguments in registers on x86. However T_OBJECT
+ * can be spilled just fine, and in that case the xor emission will fail.
+ */
+
+import java.util.concurrent.atomic.*;
+class C1ObjectSpillInLogicOp {
+ static public void main(String[] args) {
+ AtomicReferenceArray<Integer> x = new AtomicReferenceArray(128);
+ Integer y = new Integer(0);
+ for (int i = 0; i < 50000; i++) {
+ x.getAndSet(i % x.length(), y);
+ }
+ }
+}