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8234617: C1: Incorrect result of field load due to missing narrowing …

…conversion

Emit an explicit conversion to get the correct field value after the write.

Reviewed-by: vlivanov, mdoerr
  • Loading branch information
Tobias Hartmann
Tobias Hartmann committed Dec 3, 2019
1 parent c7a2e3b commit aff41433b6c615811ae6800c25cc16454b546791
@@ -1725,6 +1725,23 @@ void GraphBuilder::access_field(Bytecodes::Code code) {
Value replacement = !needs_patching ? _memory->load(load) : load;
if (replacement != load) {
assert(replacement->is_linked() || !replacement->can_be_linked(), "should already by linked");
// Writing an (integer) value to a boolean, byte, char or short field includes an implicit narrowing
// conversion. Emit an explicit conversion here to get the correct field value after the write.
BasicType bt = field->type()->basic_type();
switch (bt) {
case T_BOOLEAN:
case T_BYTE:
replacement = append(new Convert(Bytecodes::_i2b, replacement, as_ValueType(bt)));
break;
case T_CHAR:
replacement = append(new Convert(Bytecodes::_i2c, replacement, as_ValueType(bt)));
break;
case T_SHORT:
replacement = append(new Convert(Bytecodes::_i2s, replacement, as_ValueType(bt)));
break;
default:
break;
}
push(type, replacement);
} else {
push(type, append(load));
@@ -0,0 +1,130 @@
/*
* Copyright (c) 2019, 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.
*/

package compiler/conversions;

public class Conversion
version 52:0
{
Field booleanFld:Z;
Field byteFld:B;
Field charFld:C;
Field shortFld:S;
Field intFld:I;

public Method "<init>":"()V"
stack 1 locals 1
{
aload_0;
invokespecial Method java/lang/Object."<init>":"()V";
return;
}

public Method testBooleanConst:"()I"
stack 5 locals 1
{
aload_0;
ldc_w int 2; // 2^1 (maximum boolean value is 1)
putfield Field booleanFld:"Z";
aload_0;
getfield Field booleanFld:"Z";
ireturn;
}

public Method testBoolean:"(I)I"
stack 5 locals 2
{
aload_0;
iload_1;
putfield Field booleanFld:"Z";
aload_0;
getfield Field booleanFld:"Z";
ireturn;
}

public Method testByteConst:"()I"
stack 5 locals 1
{
aload_0;
ldc_w int 256; // 2^8 (maximum byte value is 2^7-1)
putfield Field byteFld:"B";
aload_0;
getfield Field byteFld:"B";
ireturn;
}

public Method testByte:"(I)I"
stack 5 locals 2
{
aload_0;
iload_1;
putfield Field byteFld:"B";
aload_0;
getfield Field byteFld:"B";
ireturn;
}

public Method testCharConst:"()I"
stack 5 locals 1
{
aload_0;
ldc_w int 131072; // 2^17 (maximum char value is 2^16-1)
putfield Field charFld:"C";
aload_0;
getfield Field charFld:"C";
ireturn;
}

public Method testChar:"(I)I"
stack 5 locals 2
{
aload_0;
iload_1;
putfield Field charFld:"C";
aload_0;
getfield Field charFld:"C";
ireturn;
}

public Method testShortConst:"()I"
stack 5 locals 1
{
aload_0;
ldc_w int 65536; // 2^16 (maximum short value is 2^15-1)
putfield Field shortFld:"S";
aload_0;
getfield Field shortFld:"S";
ireturn;
}

public Method testShort:"(I)I"
stack 5 locals 2
{
aload_0;
iload_1;
putfield Field shortFld:"S";
aload_0;
getfield Field shortFld:"S";
ireturn;
}
}
@@ -0,0 +1,60 @@
/*
* Copyright (c) 2019, 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.
*/

package compiler.conversions;

import jdk.test.lib.Asserts;

/*
* @test
* @bug 8234617
* @summary Test implicit narrowing conversion of primivite values at putfield.
* @library /test/lib /
* @compile Conversion.jasm
* @run main/othervm -Xbatch -XX:CompileCommand=dontinline,compiler.conversions.Conversion::*
* compiler.conversions.TestPrimitiveConversions
*/
public class TestPrimitiveConversions {

public static void main(String[] args) {
Conversion conv = new Conversion();
for (int i = 0; i < 100_000; ++i) {
int res = conv.testBooleanConst();
Asserts.assertEquals(res, 0);
res = conv.testBoolean(2); // 2^1 (maximum boolean value is 1)
Asserts.assertEquals(res, 0);
res = conv.testByteConst();
Asserts.assertEquals(res, 0);
res = conv.testByte(256); // 2^8 (maximum byte value is 2^7-1)
Asserts.assertEquals(res, 0);
res = conv.testCharConst();
Asserts.assertEquals(res, 0);
res = conv.testChar(131072); // 2^17 (maximum char value is 2^16-1)
Asserts.assertEquals(res, 0);
res = conv.testShortConst();
Asserts.assertEquals(res, 0);
res = conv.testShort(65536); // 2^16 (maximum short value is 2^15-1)
Asserts.assertEquals(res, 0);
}
}
}

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