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8237894: CTW: C1 compilation fails with assert(x->type()->tag() == f-…
…>type()->tag()) failed: should have same type

Field access instructions hash decalred_type in addition, indexed access instructions hash value type of the instruction in addition.

Reviewed-by: thartmann, shade
  • Loading branch information
jamsheedcm committed Mar 20, 2020
1 parent 6dffcf7 commit 136a1574ec3528f3e53f79289587e5464befa6ab
Showing with 157 additions and 17 deletions.
  1. +18 −11 src/hotspot/share/c1/c1_GraphBuilder.cpp
  2. +8 −6 src/hotspot/share/c1/c1_Instruction.hpp
  3. +131 −0 test/hotspot/jtreg/compiler/c1/TestValueNumberingNullObject.java
@@ -1,5 +1,5 @@
/*
* Copyright (c) 1999, 2019, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 1999, 2020, 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
@@ -3796,6 +3796,23 @@ bool GraphBuilder::try_inline_full(ciMethod* callee, bool holder_known, bool ign
INLINE_BAILOUT("mdo allocation failed");
}

const bool is_invokedynamic = (bc == Bytecodes::_invokedynamic);
const bool has_receiver = (bc != Bytecodes::_invokestatic && !is_invokedynamic);

const int args_base = state()->stack_size() - callee->arg_size();
assert(args_base >= 0, "stack underflow during inlining");

Value recv = NULL;
if (has_receiver) {
assert(!callee->is_static(), "callee must not be static");
assert(callee->arg_size() > 0, "must have at least a receiver");

recv = state()->stack_at(args_base);
if (recv->is_null_obj()) {
INLINE_BAILOUT("receiver is always null");
}
}

// now perform tests that are based on flag settings
bool inlinee_by_directive = compilation()->directive()->should_inline(callee);
if (callee->force_inline() || inlinee_by_directive) {
@@ -3838,21 +3855,11 @@ bool GraphBuilder::try_inline_full(ciMethod* callee, bool holder_known, bool ign

BlockBegin* orig_block = block();

const bool is_invokedynamic = bc == Bytecodes::_invokedynamic;
const bool has_receiver = (bc != Bytecodes::_invokestatic && !is_invokedynamic);

const int args_base = state()->stack_size() - callee->arg_size();
assert(args_base >= 0, "stack underflow during inlining");

// Insert null check if necessary
Value recv = NULL;
if (has_receiver) {
// note: null check must happen even if first instruction of callee does
// an implicit null check since the callee is in a different scope
// and we must make sure exception handling does the right thing
assert(!callee->is_static(), "callee must not be static");
assert(callee->arg_size() > 0, "must have at least a receiver");
recv = state()->stack_at(args_base);
null_check(recv);
}

@@ -1,5 +1,5 @@
/*
* Copyright (c) 1999, 2019, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 1999, 2020, 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
@@ -268,7 +268,7 @@ class InstructionVisitor: public StackObj {


#define HASHING3(class_name, enabled, f1, f2, f3) \
virtual intx hash() const { \
virtual intx hash() const { \
return (enabled) ? HASH4(name(), f1, f2, f3) : 0; \
} \
virtual bool is_equal(Value v) const { \
@@ -454,6 +454,8 @@ class Instruction: public CompilationResourceObj {
bool is_linked() const { return check_flag(IsLinkedInBlockFlag); }
bool can_be_linked() { return as_Local() == NULL && as_Phi() == NULL; }

bool is_null_obj() { return as_Constant() != NULL && type()->as_ObjectType()->constant_value()->is_null_object(); }

bool has_uses() const { return use_count() > 0; }
ValueStack* state_before() const { return _state_before; }
ValueStack* exception_state() const { return _exception_state; }
@@ -834,8 +836,8 @@ LEAF(LoadField, AccessField)

ciType* declared_type() const;

// generic
HASHING2(LoadField, !needs_patching() && !field()->is_volatile(), obj()->subst(), offset()) // cannot be eliminated if needs patching or if volatile
// generic; cannot be eliminated if needs patching or if volatile.
HASHING3(LoadField, !needs_patching() && !field()->is_volatile(), obj()->subst(), offset(), declared_type())
};


@@ -964,8 +966,8 @@ LEAF(LoadIndexed, AccessIndexed)
ciType* exact_type() const;
ciType* declared_type() const;

// generic
HASHING2(LoadIndexed, true, array()->subst(), index()->subst())
// generic;
HASHING3(LoadIndexed, true, type()->tag(), array()->subst(), index()->subst())
};


@@ -0,0 +1,131 @@
/*
* Copyright (c) 2020, 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 8237894
* @summary CTW: C1 compilation fails with assert(x->type()->tag() == f->type()->tag()) failed: should have same type
*
* @run main/othervm
* -Xcomp -Xbatch -XX:CompileCommand=compileonly,compiler.c1.T*::*
* -XX:CompileCommand=exclude,compiler.c1.TestValueNumberingNullObject::main
* -XX:CompileCommand=inline,*.*
* -XX:TieredStopAtLevel=3
* compiler.c1.TestValueNumberingNullObject
*/

package compiler.c1;

class T1 {

public T2 f1;

public int za() {
return 0;
}

public int zb() {
return 0;
}

public int zc() {
return 0;
}

public int zd() {
return 0;
}

public int ze() {
return 0;
}

public int zf() {
return 0;
}

public int zg() {
return 0;
}

public int zh() {
return 0;
}
}

class T2 {

public T1 f1;

public int zh() {
return 0;
}
}

public class TestValueNumberingNullObject {

public static void main(String args[]) {
new T1(); // Load
new T2(); // Load
try {
// case 1
// Null based field access.
// Value Numbering null based field access causes instructions to be eliminated across type/subtypes.
// declared type of these instructions are field type, so it being receiver causes problems to Type System.
// to mitigate this issue, we hash declared type in addition to existing hashing.
testFieldAccess();
} catch (Exception e) {
}
try {
// case 2
// Null based indexed access.
// Value Numbering null based indexed access causes instructions to be eliminated across type/subtypes.
// element basic type in encoded in the access instruction, this causes problems to Type system.
// declared type of these instructions are null, so it being receiver doesn't cause any problem to Type System.
// to mitigate this issue, we hash basic type in addition to existing hashing
basicTypeAccess();
} catch (Exception e) {
}
}

static long testFieldAccess() {
T1 t1 = null;
T2 t2 = null;
T1[] t3 = null;
T2[] t4 = null;

long value = t1.f1.zh() + t2.f1.zh();
// null array object based field access.
value += t3[2].f1.zh() + t4[2].f1.zh();
return value;
}

static long basicTypeAccess() {
long[] f1 = null;
int[] f2 = null;
T2[] t2 = null;
T1[] t1 = null;
return f1[5] + f2[5] + t2[5].zh() + t1[5].zh();
}
}

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