/hg/icedtea8-forest/hotspot: 2 new changesets
andrew at icedtea.classpath.org
andrew at icedtea.classpath.org
Mon Nov 12 04:48:13 UTC 2018
changeset 2eb3eef042bd in /hg/icedtea8-forest/hotspot
details: http://icedtea.classpath.org/hg/icedtea8-forest/hotspot?cmd=changeset;node=2eb3eef042bd
author: thartmann
date: Mon Oct 15 11:00:27 2018 +0200
8172850, PR3643, RH1640127: Anti-dependency on membar causes crash in register allocator due to invalid instruction scheduling
Summary: Regression test and additional asserts. The problem is fixed by 8087341.
Reviewed-by: kvn
changeset ccf1620f18d3 in /hg/icedtea8-forest/hotspot
details: http://icedtea.classpath.org/hg/icedtea8-forest/hotspot?cmd=changeset;node=ccf1620f18d3
author: roland
date: Wed Oct 24 10:42:54 2018 +0200
8209639, PR3643, RH1640127: assert failure in coalesce.cpp: attempted to spill a non-spillable item
Reviewed-by: neliasso, kvn
diffstat:
src/share/vm/opto/cfgnode.cpp | 1 +
src/share/vm/opto/coalesce.cpp | 32 +++++-
src/share/vm/opto/machnode.cpp | 1 +
src/share/vm/opto/matcher.cpp | 3 +
test/compiler/c2/SubsumingLoadsCauseFlagSpill.java | 72 ++++++++++++++
test/compiler/gcbarriers/TestMembarDependencies.java | 98 ++++++++++++++++++++
6 files changed, 204 insertions(+), 3 deletions(-)
diffs (290 lines):
diff -r de4f1f9fbcc5 -r ccf1620f18d3 src/share/vm/opto/cfgnode.cpp
--- a/src/share/vm/opto/cfgnode.cpp Thu Sep 22 12:17:24 2016 +0200
+++ b/src/share/vm/opto/cfgnode.cpp Wed Oct 24 10:42:54 2018 +0200
@@ -2016,6 +2016,7 @@
uint ideal_reg = _type->ideal_reg();
assert( ideal_reg != Node::NotAMachineReg, "invalid type at Phi" );
if( ideal_reg == 0 ) return RegMask::Empty;
+ assert(ideal_reg != Op_RegFlags, "flags register is not spillable");
return *(Compile::current()->matcher()->idealreg2spillmask[ideal_reg]);
}
diff -r de4f1f9fbcc5 -r ccf1620f18d3 src/share/vm/opto/coalesce.cpp
--- a/src/share/vm/opto/coalesce.cpp Thu Sep 22 12:17:24 2016 +0200
+++ b/src/share/vm/opto/coalesce.cpp Wed Oct 24 10:42:54 2018 +0200
@@ -25,6 +25,7 @@
#include "precompiled.hpp"
#include "memory/allocation.inline.hpp"
#include "opto/block.hpp"
+#include "opto/c2compiler.hpp"
#include "opto/cfgnode.hpp"
#include "opto/chaitin.hpp"
#include "opto/coalesce.hpp"
@@ -292,7 +293,18 @@
// Copy any flags as well
_phc.clone_projs(pred, pred->end_idx(), m, copy, _phc._lrg_map);
} else {
- const RegMask *rm = C->matcher()->idealreg2spillmask[m->ideal_reg()];
+ int ireg = m->ideal_reg();
+ if (ireg == 0 || ireg == Op_RegFlags) {
+ if (C->subsume_loads()) {
+ C->record_failure(C2Compiler::retry_no_subsuming_loads());
+ } else {
+ assert(false, err_msg("attempted to spill a non-spillable item: %d: %s, ireg = %d",
+ m->_idx, m->Name(), ireg));
+ C->record_method_not_compilable("attempted to spill a non-spillable item");
+ }
+ return;
+ }
+ const RegMask *rm = C->matcher()->idealreg2spillmask[ireg];
copy = new (C) MachSpillCopyNode(m, *rm, *rm);
// Find a good place to insert. Kinda tricky, use a subroutine
insert_copy_with_overlap(pred,copy,phi_name,src_name);
@@ -326,7 +338,14 @@
b->insert_node(copy, l++);
l += _phc.clone_projs(b, l, m, copy, _phc._lrg_map);
} else {
- const RegMask *rm = C->matcher()->idealreg2spillmask[m->ideal_reg()];
+ int ireg = m->ideal_reg();
+ if (ireg == 0 || ireg == Op_RegFlags) {
+ assert(false, err_msg("attempted to spill a non-spillable item: %d: %s, ireg = %d",
+ m->_idx, m->Name(), ireg));
+ C->record_method_not_compilable("attempted to spill a non-spillable item");
+ return;
+ }
+ const RegMask *rm = C->matcher()->idealreg2spillmask[ireg];
copy = new (C) MachSpillCopyNode(m, *rm, *rm);
// Insert the copy in the basic block, just before us
b->insert_node(copy, l++);
@@ -373,7 +392,14 @@
if( k < b->_num_succs )
continue; // Live out; do not pre-split
// Split the lrg at this use
- const RegMask *rm = C->matcher()->idealreg2spillmask[inp->ideal_reg()];
+ int ireg = inp->ideal_reg();
+ if (ireg == 0 || ireg == Op_RegFlags) {
+ assert(false, err_msg("attempted to spill a non-spillable item: %d: %s, ireg = %d",
+ inp->_idx, inp->Name(), ireg));
+ C->record_method_not_compilable("attempted to spill a non-spillable item");
+ return;
+ }
+ const RegMask *rm = C->matcher()->idealreg2spillmask[ireg];
Node *copy = new (C) MachSpillCopyNode( inp, *rm, *rm );
// Insert the copy in the use-def chain
n->set_req(inpidx, copy );
diff -r de4f1f9fbcc5 -r ccf1620f18d3 src/share/vm/opto/machnode.cpp
--- a/src/share/vm/opto/machnode.cpp Thu Sep 22 12:17:24 2016 +0200
+++ b/src/share/vm/opto/machnode.cpp Wed Oct 24 10:42:54 2018 +0200
@@ -619,6 +619,7 @@
}
// Values outside the domain represent debug info
+ assert(in(idx)->ideal_reg() != Op_RegFlags, "flags register is not spillable");
return *Compile::current()->matcher()->idealreg2spillmask[in(idx)->ideal_reg()];
}
diff -r de4f1f9fbcc5 -r ccf1620f18d3 src/share/vm/opto/matcher.cpp
--- a/src/share/vm/opto/matcher.cpp Thu Sep 22 12:17:24 2016 +0200
+++ b/src/share/vm/opto/matcher.cpp Wed Oct 24 10:42:54 2018 +0200
@@ -97,6 +97,7 @@
idealreg2spillmask [Op_VecD] = NULL;
idealreg2spillmask [Op_VecX] = NULL;
idealreg2spillmask [Op_VecY] = NULL;
+ idealreg2spillmask [Op_RegFlags] = NULL;
idealreg2debugmask [Op_RegI] = NULL;
idealreg2debugmask [Op_RegN] = NULL;
@@ -108,6 +109,7 @@
idealreg2debugmask [Op_VecD] = NULL;
idealreg2debugmask [Op_VecX] = NULL;
idealreg2debugmask [Op_VecY] = NULL;
+ idealreg2debugmask [Op_RegFlags] = NULL;
idealreg2mhdebugmask[Op_RegI] = NULL;
idealreg2mhdebugmask[Op_RegN] = NULL;
@@ -119,6 +121,7 @@
idealreg2mhdebugmask[Op_VecD] = NULL;
idealreg2mhdebugmask[Op_VecX] = NULL;
idealreg2mhdebugmask[Op_VecY] = NULL;
+ idealreg2mhdebugmask[Op_RegFlags] = NULL;
debug_only(_mem_node = NULL;) // Ideal memory node consumed by mach node
}
diff -r de4f1f9fbcc5 -r ccf1620f18d3 test/compiler/c2/SubsumingLoadsCauseFlagSpill.java
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/test/compiler/c2/SubsumingLoadsCauseFlagSpill.java Wed Oct 24 10:42:54 2018 +0200
@@ -0,0 +1,72 @@
+/*
+ * Copyright (c) 2018, Red Hat, 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 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 8209639
+ * @summary assert failure in coalesce.cpp: attempted to spill a non-spillable item
+ *
+ * @run main/othervm -XX:-BackgroundCompilation -XX:CompileCommand=dontinline,SubsumingLoadsCauseFlagSpill::not_inlined -Xmx1024m SubsumingLoadsCauseFlagSpill
+ *
+ */
+
+public class SubsumingLoadsCauseFlagSpill {
+ private static Object field;
+ private static boolean do_throw;
+ private static volatile boolean barrier;
+
+ public static void main(String[] args) {
+ for (int i = 0; i < 20_000; i++) {
+ do_throw = true;
+ field = null;
+ test(0);
+ do_throw = false;
+ field = new Object();
+ test(0);
+ }
+ }
+
+ private static float test(float f) {
+ Object v = null;
+ try {
+ not_inlined();
+ v = field;
+ } catch (MyException me) {
+ v = field;
+ barrier = true;
+ }
+ if (v == null) {
+ return f * f;
+ }
+ return f;
+ }
+
+ private static void not_inlined() throws MyException{
+ if (do_throw) {
+ throw new MyException();
+ }
+ }
+
+ private static class MyException extends Throwable {
+ }
+}
diff -r de4f1f9fbcc5 -r ccf1620f18d3 test/compiler/gcbarriers/TestMembarDependencies.java
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/test/compiler/gcbarriers/TestMembarDependencies.java Wed Oct 24 10:42:54 2018 +0200
@@ -0,0 +1,98 @@
+/*
+ * Copyright (c) 2017, 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 TestMembarDependencies
+ * @bug 8172850
+ * @summary Tests correct scheduling of memory loads around MembarVolatile emitted by GC barriers.
+ * @library /testlibrary
+ * @run driver compiler.membars.TestMembarDependencies
+ */
+
+package compiler.membars;
+
+import com.oracle.java.testlibrary.*;
+
+public class TestMembarDependencies {
+ private static TestMembarDependencies f1;
+ private static TestMembarDependencies f2;
+
+ public static void main(String args[]) throws Throwable {
+ if (args.length == 0) {
+ // For debugging, add "-XX:+TraceOptoPipelining"
+ OutputAnalyzer oa = ProcessTools.executeTestJvm("-XX:+IgnoreUnrecognizedVMOptions",
+ "-XX:-TieredCompilation", "-XX:-BackgroundCompilation", "-XX:+PrintOpto",
+ "-XX:CompileCommand=compileonly,compiler.membars.TestMembarDependencies::test*",
+ "-XX:CompileCommand=dontinline,compiler.membars.TestMembarDependencies::test_m1",
+ TestMembarDependencies.class.getName(), "run");
+ // C2 should not crash or bail out from compilation
+ oa.shouldHaveExitValue(0);
+ oa.shouldNotMatch("Bailout: Recompile without subsuming loads");
+ System.out.println(oa.getOutput());
+ } else {
+ f2 = new TestMembarDependencies();
+ // Trigger compilation of test1 and test2
+ for (int i = 0; i < 10_000; ++i) {
+ f2.test1(f2);
+ f2.test2(f2);
+ }
+ }
+ }
+
+ public void test_m1() { }
+ public void test_m2() { }
+
+ public void test1(TestMembarDependencies obj) {
+ // Try/catch/finally is used to create a CFG block without a test + jmpCon
+ // allowing GCM to schedule the testN_mem_reg0 instruction into that block.
+ try {
+ // Method call defines memory state that is then
+ // used by subsequent instructions/blocks (see below).
+ test_m1();
+ } catch (Exception e) {
+
+ } finally {
+ // Oop write to field emits a GC post-barrier with a MembarVolatile
+ // which has a wide memory effect (kills all memory). This creates an
+ // anti-dependency on all surrounding memory loads.
+ f1 = obj;
+ }
+ // The empty method m2 is inlined but the null check of f2 remains. It is encoded
+ // as CmpN(LoadN(MEM), NULL) where MEM is the memory after the call to test_m1().
+ // This is matched to testN_mem_reg0 on x86 which is scheduled before the barrier
+ // in the try/catch block due to the anti-dependency on the MembarVolatile.
+ // C2 crashes in the register allocator when trying to spill the flag register
+ // to keep the result of the testN instruction live from the try/catch block
+ // until it is here.
+ f2.test_m2();
+ }
+
+ public void test2(TestMembarDependencies obj) {
+ // Same as test1 but without try/catch/finally.
+ // This causes C2 to bail out in block local scheduling because testN_mem_reg0 is
+ // scheduled into a block that already contains another test + jmpCon instruction.
+ test_m1();
+ f1 = obj;
+ f2.test_m2();
+ }
+}
More information about the distro-pkg-dev
mailing list