# HG changeset patch
# User kbarrett
# Date 1573161742 18000
# Node ID 291775bcf35da7646eb2d72db0eb7fc2a78bc404
# Parent  dc998d4a227ee3aa37525f19aa980da094a202b6
8233364: Fix undefined behavior in Canonicalizer::do_ShiftOp
Summary: Add java_shift_xxx helpers and use them.
Reviewed-by: aph, kvn

diff -r dc998d4a227e -r 291775bcf35d src/hotspot/share/c1/c1_Canonicalizer.cpp
--- a/src/hotspot/share/c1/c1_Canonicalizer.cpp	Thu Nov 07 11:34:01 2019 -0800
+++ b/src/hotspot/share/c1/c1_Canonicalizer.cpp	Thu Nov 07 16:22:22 2019 -0500
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1999, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1999, 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
@@ -354,25 +354,21 @@
     }
     if (t2->is_constant()) {
       if (t->tag() == intTag) {
-        int value = t->as_IntConstant()->value();
-        int shift = t2->as_IntConstant()->value() & 31;
-        jint mask = ~(~0 << (32 - shift));
-        if (shift == 0) mask = ~0;
+        jint value = t->as_IntConstant()->value();
+        jint shift = t2->as_IntConstant()->value();
         switch (x->op()) {
-          case Bytecodes::_ishl:  set_constant(value << shift); return;
-          case Bytecodes::_ishr:  set_constant(value >> shift); return;
-          case Bytecodes::_iushr: set_constant((value >> shift) & mask); return;
+          case Bytecodes::_ishl:  set_constant(java_shift_left(value, shift)); return;
+          case Bytecodes::_ishr:  set_constant(java_shift_right(value, shift)); return;
+          case Bytecodes::_iushr: set_constant(java_shift_right_unsigned(value, shift)); return;
           default:                break;
         }
       } else if (t->tag() == longTag) {
         jlong value = t->as_LongConstant()->value();
-        int shift = t2->as_IntConstant()->value() & 63;
-        jlong mask = ~(~jlong_cast(0) << (64 - shift));
-        if (shift == 0) mask = ~jlong_cast(0);
+        jint shift = t2->as_IntConstant()->value();
         switch (x->op()) {
-          case Bytecodes::_lshl:  set_constant(value << shift); return;
-          case Bytecodes::_lshr:  set_constant(value >> shift); return;
-          case Bytecodes::_lushr: set_constant((value >> shift) & mask); return;
+          case Bytecodes::_lshl:  set_constant(java_shift_left(value, shift)); return;
+          case Bytecodes::_lshr:  set_constant(java_shift_right(value, shift)); return;
+          case Bytecodes::_lushr: set_constant(java_shift_right_unsigned(value, shift)); return;
           default:                break;
         }
       }
diff -r dc998d4a227e -r 291775bcf35d src/hotspot/share/utilities/globalDefinitions.hpp
--- a/src/hotspot/share/utilities/globalDefinitions.hpp	Thu Nov 07 11:34:01 2019 -0800
+++ b/src/hotspot/share/utilities/globalDefinitions.hpp	Thu Nov 07 16:22:22 2019 -0500
@@ -1110,6 +1110,33 @@
 
 #undef JAVA_INTEGER_OP
 
+// Provide integer shift operations with Java semantics.  No overflow
+// issues - left shifts simply discard shifted out bits.  No undefined
+// behavior for large or negative shift quantities; instead the actual
+// shift distance is the argument modulo the lhs value's size in bits.
+// No undefined or implementation defined behavior for shifting negative
+// values; left shift discards bits, right shift sign extends.  We use
+// the same safe conversion technique as above for java_add and friends.
+#define JAVA_INTEGER_SHIFT_OP(OP, NAME, TYPE, XTYPE)    \
+inline TYPE NAME (TYPE lhs, jint rhs) {                 \
+  const uint rhs_mask = (sizeof(TYPE) * 8) - 1;         \
+  STATIC_ASSERT(rhs_mask == 31 || rhs_mask == 63);      \
+  XTYPE xres = static_cast<XTYPE>(lhs);                 \
+  xres OP ## = (rhs & rhs_mask);                        \
+  return reinterpret_cast<TYPE&>(xres);                 \
+}
+
+JAVA_INTEGER_SHIFT_OP(<<, java_shift_left, jint, juint)
+JAVA_INTEGER_SHIFT_OP(<<, java_shift_left, jlong, julong)
+// For signed shift right, assume C++ implementation >> sign extends.
+JAVA_INTEGER_SHIFT_OP(>>, java_shift_right, jint, jint)
+JAVA_INTEGER_SHIFT_OP(>>, java_shift_right, jlong, jlong)
+// For >>> use C++ unsigned >>.
+JAVA_INTEGER_SHIFT_OP(>>, java_shift_right_unsigned, jint, juint)
+JAVA_INTEGER_SHIFT_OP(>>, java_shift_right_unsigned, jlong, julong)
+
+#undef JAVA_INTEGER_SHIFT_OP
+
 //----------------------------------------------------------------------------------------------------
 // The goal of this code is to provide saturating operations for int/uint.
 // Checks overflow conditions and saturates the result to min_jint/max_jint.
diff -r dc998d4a227e -r 291775bcf35d test/hotspot/gtest/utilities/test_java_arithmetic.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/hotspot/gtest/utilities/test_java_arithmetic.cpp	Thu Nov 07 16:22:22 2019 -0500
@@ -0,0 +1,346 @@
+/*
+ * 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.
+ *
+ */
+
+#include "precompiled.hpp"
+#include "memory/allocation.hpp"
+#include "utilities/globalDefinitions.hpp"
+#include "unittest.hpp"
+
+class TestJavaArithSupport : public AllStatic {
+public:
+  template<typename T> struct BinOpData { T x; T y; T r; };
+  template<typename T> struct ShiftOpData { T x; jint shift; T r; };
+};
+
+typedef TestJavaArithSupport::BinOpData<jint> BinOpJintData;
+typedef TestJavaArithSupport::BinOpData<jlong> BinOpJlongData;
+
+typedef TestJavaArithSupport::ShiftOpData<jint> ShiftOpJintData;
+typedef TestJavaArithSupport::ShiftOpData<jlong> ShiftOpJlongData;
+
+const BinOpJintData add_jint_data[] = {
+  { 0, 0, 0 },
+  { 0, 1, 1 },
+  { 0, -1, -1 },
+  { max_jint, 1, min_jint },
+  { max_jint, -1, max_jint - 1 },
+  { min_jint, 1, min_jint + 1 },
+  { min_jint, -1, max_jint },
+  { max_jint, 10, min_jint + 9 },
+  { max_jint, -10, max_jint - 10 },
+  { min_jint, 10, min_jint + 10 },
+  { min_jint, -10, max_jint - 9 },
+  { max_jint, max_jint, -2 },
+  { min_jint, min_jint, 0 }
+};
+
+const BinOpJlongData add_jlong_data[] = {
+  { 0, 0, 0 },
+  { 0, 1, 1 },
+  { 0, -1, -1 },
+  { max_jlong, 1, min_jlong },
+  { max_jlong, -1, max_jlong - 1 },
+  { min_jlong, 1, min_jlong + 1 },
+  { min_jlong, -1, max_jlong },
+  { max_jlong, 10, min_jlong + 9 },
+  { max_jlong, -10, max_jlong - 10 },
+  { min_jlong, 10, min_jlong + 10 },
+  { min_jlong, -10, max_jlong - 9 },
+  { max_jlong, max_jlong, -2 },
+  { min_jlong, min_jlong, 0 }
+};
+
+TEST(TestJavaArithmetic, add_sub_jint) {
+  const volatile BinOpJintData* data = add_jint_data;
+  for (size_t i = 0; i < ARRAY_SIZE(add_jint_data); ++i) {
+    ASSERT_EQ(data[i].r, java_add(data[i].x, data[i].y));
+    ASSERT_EQ(data[i].r, java_add(data[i].y, data[i].x));
+    ASSERT_EQ(data[i].x, java_subtract(data[i].r, data[i].y));
+    ASSERT_EQ(data[i].y, java_subtract(data[i].r, data[i].x));
+  }
+}
+
+TEST(TestJavaArithmetic, add_sub_jlong) {
+  const volatile BinOpJlongData* data = add_jlong_data;
+  for (size_t i = 0; i < ARRAY_SIZE(add_jlong_data); ++i) {
+    ASSERT_EQ(data[i].r, java_add(data[i].x, data[i].y));
+    ASSERT_EQ(data[i].r, java_add(data[i].y, data[i].x));
+    ASSERT_EQ(data[i].x, java_subtract(data[i].r, data[i].y));
+    ASSERT_EQ(data[i].y, java_subtract(data[i].r, data[i].x));
+  }
+}
+
+static const BinOpJintData mul_jint_data[] = {
+  { 0, 0, 0 },
+  { 0, 1, 0 },
+  { 0, max_jint, 0 },
+  { 0, min_jint, 0 },
+  { 1, 1, 1 },
+  { 1, max_jint, max_jint },
+  { 1, min_jint, min_jint },
+  { -1, 1, -1 },
+  { -1, max_jint, min_jint + 1 },
+  { 5, max_jint, max_jint - 4 },
+  { -5, max_jint, min_jint + 5 },
+  { max_jint, max_jint, 1 },
+  { max_jint, min_jint, min_jint },
+  { min_jint, min_jint, 0 }
+};
+
+static const BinOpJlongData mul_jlong_data[] = {
+  { 0, 0, 0 },
+  { 0, 1, 0 },
+  { 0, max_jlong, 0 },
+  { 0, min_jlong, 0 },
+  { 1, 1, 1 },
+  { 1, max_jlong, max_jlong },
+  { 1, min_jlong, min_jlong },
+  { -1, 1, -1 },
+  { -1, max_jlong, min_jlong + 1 },
+  { 5, max_jlong, max_jlong - 4 },
+  { -5, max_jlong, min_jlong + 5 },
+  { max_jlong, max_jlong, 1 },
+  { max_jlong, min_jlong, min_jlong },
+  { min_jlong, min_jlong, 0 }
+};
+
+TEST(TestJavaArithmetic, mul_jint) {
+  const volatile BinOpJintData* data = mul_jint_data;
+  for (size_t i = 0; i < ARRAY_SIZE(mul_jint_data); ++i) {
+    ASSERT_EQ(data[i].r, java_multiply(data[i].x, data[i].y));
+    ASSERT_EQ(data[i].r, java_multiply(data[i].y, data[i].x));
+  }
+}
+
+TEST(TestJavaArithmetic, mul_jlong) {
+  const volatile BinOpJlongData* data = mul_jlong_data;
+  for (size_t i = 0; i < ARRAY_SIZE(mul_jlong_data); ++i) {
+    ASSERT_EQ(data[i].r, java_multiply(data[i].x, data[i].y));
+    ASSERT_EQ(data[i].r, java_multiply(data[i].y, data[i].x));
+  }
+}
+
+static const ShiftOpJintData asl_jint_data[] = {
+  { 0, 0, 0 },
+  { 0, 10, 0 },
+  { 0, 50, 0 },
+  { 1, 0, 1 },
+  { 1, 10, (jint)1 << 10 },
+  { 1, 50, (jint)1 << 18 },
+  { 5, 0, 5 },
+  { 5, 10, (jint)5 << 10 },
+  { 5, 50, (jint)5 << 18 },
+  { -1, 0, -1 },
+  { -1, 10, (jint)-1 * (1 << 10) },
+  { -1, 50, (jint)-1 * (1 << 18) },
+  { -5, 0, -5 },
+  { -5, 10, (jint)-5 * (1 << 10) },
+  { -5, 50, (jint)-5 * (1 << 18) },
+  { max_jint, 0, max_jint },
+  { max_jint, 10, (jint)0xFFFFFC00 },
+  { max_jint, 50, (jint)0xFFFC0000 },
+  { min_jint, 0, min_jint },
+  { min_jint, 10, 0 },
+  { min_jint, 50, 0 }
+};
+
+static const ShiftOpJlongData asl_jlong_data[] = {
+  { 0, 0, 0 },
+  { 0, 10, 0 },
+  { 0, 82, 0 },
+  { 1, 0, 1 },
+  { 1, 10, (jlong)1 << 10 },
+  { 1, 82, (jlong)1 << 18 },
+  { 5, 0, 5 },
+  { 5, 10, (jlong)5 << 10 },
+  { 5, 82, (jlong)5 << 18 },
+  { -1, 0, -1 },
+  { -1, 10, (jlong)-1 * (1 << 10) },
+  { -1, 82, (jlong)-1 * (1 << 18) },
+  { -5, 0, -5 },
+  { -5, 10, (jlong)-5 * (1 << 10) },
+  { -5, 82, (jlong)-5 * (1 << 18) },
+  { max_jlong, 0, max_jlong },
+  { max_jlong, 10, (jlong)0xFFFFFFFFFFFFFC00 },
+  { max_jlong, 82, (jlong)0xFFFFFFFFFFFC0000 },
+  { min_jlong, 0, min_jlong },
+  { min_jlong, 10, 0 },
+  { min_jlong, 82, 0 }
+};
+
+TEST(TestJavaArithmetic, shift_left_jint) {
+  const volatile ShiftOpJintData* data = asl_jint_data;
+  for (size_t i = 0; i < ARRAY_SIZE(asl_jint_data); ++i) {
+    ASSERT_EQ(data[i].r, java_shift_left(data[i].x, data[i].shift));
+  }
+}
+
+TEST(TestJavaArithmetic, shift_left_jlong) {
+  const volatile ShiftOpJlongData* data = asl_jlong_data;
+  for (size_t i = 0; i < ARRAY_SIZE(asl_jlong_data); ++i) {
+    ASSERT_EQ(data[i].r, java_shift_left(data[i].x, data[i].shift));
+  }
+}
+
+static const ShiftOpJintData asr_jint_data[] = {
+  { 0, 0, 0 },
+  { 0, 10, 0 },
+  { 0, 50, 0 },
+  { 1, 0, 1 },
+  { 1, 10, 0 },
+  { 1, 50, 0 },
+  { 5, 0, 5 },
+  { 5, 1, 2 },
+  { 5, 10, 0 },
+  { 5, 33, 2 },
+  { 5, 50, 0 },
+  { -1, 0, -1 },
+  { -1, 10, -1 },
+  { -1, 50, -1 },
+  { -5, 0, -5 },
+  { -5, 1, -3 },
+  { -5, 10, -1 },
+  { -5, 33, -3 },
+  { -5, 50, -1 },
+  { max_jint, 0, max_jint },
+  { max_jint, 10, (jint)0x001FFFFF },
+  { max_jint, 50, (jint)0x00001FFF },
+  { min_jint, 0, min_jint },
+  { min_jint, 10, (jint)0xFFE00000 },
+  { min_jint, 50, (jint)0xFFFFE000 }
+};
+
+static const ShiftOpJlongData asr_jlong_data[] = {
+  { 0, 0, 0 },
+  { 0, 10, 0 },
+  { 0, 82, 0 },
+  { 1, 0, 1 },
+  { 1, 10, 0 },
+  { 1, 82, 0 },
+  { 5, 0, 5 },
+  { 5, 1, 2 },
+  { 5, 10, 0 },
+  { 5, 65, 2 },
+  { 5, 82, 0 },
+  { -1, 0, -1 },
+  { -1, 10, -1 },
+  { -1, 82, -1 },
+  { -5, 0, -5 },
+  { -5, 1, -3 },
+  { -5, 10, -1 },
+  { -5, 65, -3 },
+  { -5, 82, -1 },
+  { max_jlong, 0, max_jlong },
+  { max_jlong, 10, (jlong)0x001FFFFFFFFFFFFF },
+  { max_jlong, 82, (jlong)0x00001FFFFFFFFFFF },
+  { min_jlong, 0, min_jlong },
+  { min_jlong, 10, (jlong)0xFFE0000000000000 },
+  { min_jlong, 82, (jlong)0xFFFFE00000000000 }
+};
+
+TEST(TestJavaArithmetic, shift_right_jint) {
+  const volatile ShiftOpJintData* data = asr_jint_data;
+  for (size_t i = 0; i < ARRAY_SIZE(asr_jint_data); ++i) {
+    ASSERT_EQ(data[i].r, java_shift_right(data[i].x, data[i].shift));
+  }
+}
+
+TEST(TestJavaArithmetic, shift_right_jlong) {
+  const volatile ShiftOpJlongData* data = asr_jlong_data;
+  for (size_t i = 0; i < ARRAY_SIZE(asr_jlong_data); ++i) {
+    ASSERT_EQ(data[i].r, java_shift_right(data[i].x, data[i].shift));
+  }
+}
+
+static const ShiftOpJintData lsr_jint_data[] = {
+  { 0, 0, 0 },
+  { 0, 10, 0 },
+  { 0, 50, 0 },
+  { 1, 0, 1 },
+  { 1, 10, 0 },
+  { 1, 50, 0 },
+  { 5, 0, 5 },
+  { 5, 1, 2 },
+  { 5, 10, 0 },
+  { 5, 33, 2 },
+  { 5, 50, 0 },
+  { -1, 0, -1 },
+  { -1, 10, (jint)0x003FFFFF },
+  { -1, 50, (jint)0x00003FFF },
+  { -5, 0, -5 },
+  { -5, 1, (jint)0x7FFFFFFD },
+  { -5, 10, (jint)0x003FFFFF },
+  { -5, 50, (jint)0x00003FFF },
+  { max_jint, 0, max_jint },
+  { max_jint, 1, (jint)0x3FFFFFFF },
+  { max_jint, 10, (jint)0x001FFFFF },
+  { max_jint, 50, (jint)0x00001FFF },
+  { min_jint, 0, min_jint },
+  { min_jint, 1, (jint)0x40000000 },
+  { min_jint, 10, (jint)0x00200000 },
+  { min_jint, 50, (jint)0x00002000 }
+};
+
+static const ShiftOpJlongData lsr_jlong_data[] = {
+  { 0, 0, 0 },
+  { 0, 10, 0 },
+  { 0, 82, 0 },
+  { 1, 0, 1 },
+  { 1, 10, 0 },
+  { 1, 82, 0 },
+  { 5, 0, 5 },
+  { 5, 1, 2 },
+  { 5, 10, 0 },
+  { 5, 65, 2 },
+  { 5, 82, 0 },
+  { -1, 0, -1 },
+  { -1, 10, (jlong)0x003FFFFFFFFFFFFF },
+  { -1, 82, (jlong)0x00003FFFFFFFFFFF },
+  { -5, 0, -5 },
+  { -5, 1, (jlong)0x7FFFFFFFFFFFFFFD },
+  { -5, 10, (jlong)0x003FFFFFFFFFFFFF },
+  { -5, 82, (jlong)0x00003FFFFFFFFFFF },
+  { max_jlong, 0, max_jlong },
+  { max_jlong, 1, (jlong)0x3FFFFFFFFFFFFFFF },
+  { max_jlong, 10, (jlong)0x001FFFFFFFFFFFFF },
+  { max_jlong, 82, (jlong)0x00001FFFFFFFFFFF },
+  { min_jlong, 0, min_jlong },
+  { min_jlong, 1, (jlong)0x4000000000000000 },
+  { min_jlong, 10, (jlong)0x0020000000000000 },
+  { min_jlong, 82, (jlong)0x0000200000000000 }
+};
+
+TEST(TestJavaArithmetic, shift_right_unsigned_jint) {
+  const volatile ShiftOpJintData* data = lsr_jint_data;
+  for (size_t i = 0; i < ARRAY_SIZE(lsr_jint_data); ++i) {
+    ASSERT_EQ(data[i].r, java_shift_right_unsigned(data[i].x, data[i].shift));
+  }
+}
+
+TEST(TestJavaArithmetic, shift_right_unsigned_jlong) {
+  const volatile ShiftOpJlongData* data = lsr_jlong_data;
+  for (size_t i = 0; i < ARRAY_SIZE(lsr_jlong_data); ++i) {
+    ASSERT_EQ(data[i].r, java_shift_right_unsigned(data[i].x, data[i].shift));
+  }
+}