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8258242: Type profile pollution occurs when memory segments of different kinds are used

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Reviewed-by: vlivanov, redestad
This commit is contained in:
Maurizio Cimadamore 2020-12-15 13:50:40 +00:00
parent 09e8675f56
commit 7ff9c85639
8 changed files with 225 additions and 10 deletions
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18
src/java.base/share/classes/jdk/internal/access/foreign/MemorySegmentProxy.java
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@ -29,21 +29,21 @@ package jdk.internal.access.foreign;
import jdk.internal.misc.ScopedMemoryAccess;
/**
* This proxy interface is required to allow instances of the {@code MemorySegment} interface (which is defined inside
* This abstract class is required to allow implementations of the {@code MemorySegment} interface (which is defined inside
* an incubating module) to be accessed from the memory access var handles.
*/
public interface MemorySegmentProxy {
public abstract class MemorySegmentProxy {
/**
* Check that memory access is within spatial bounds and that access is compatible with segment access modes.
* @throws UnsupportedOperationException if underlying segment has incompatible access modes (e.g. attempting to write
* a read-only segment).
* @throws IndexOutOfBoundsException if access is out-of-bounds.
*/
void checkAccess(long offset, long length, boolean readOnly);
long unsafeGetOffset();
Object unsafeGetBase();
boolean isSmall();
ScopedMemoryAccess.Scope scope();
public abstract void checkAccess(long offset, long length, boolean readOnly);
public abstract long unsafeGetOffset();
public abstract Object unsafeGetBase();
public abstract boolean isSmall();
public abstract ScopedMemoryAccess.Scope scope();
/* Helper functions for offset computations. These are required so that we can avoid issuing long opcodes
* (e.g. LMUL, LADD) when we're operating on 'small' segments (segments whose length can be expressed with an int).
@ -51,7 +51,7 @@ public interface MemorySegmentProxy {
* BCE when working with small segments. This workaround should be dropped when JDK-8223051 is resolved.
*/
static long addOffsets(long op1, long op2, MemorySegmentProxy segmentProxy) {
public static long addOffsets(long op1, long op2, MemorySegmentProxy segmentProxy) {
if (segmentProxy.isSmall()) {
// force ints for BCE
if (op1 > Integer.MAX_VALUE || op2 > Integer.MAX_VALUE
@ -74,7 +74,7 @@ public interface MemorySegmentProxy {
}
}
static long multiplyOffsets(long op1, long op2, MemorySegmentProxy segmentProxy) {
public static long multiplyOffsets(long op1, long op2, MemorySegmentProxy segmentProxy) {
if (segmentProxy.isSmall()) {
if (op1 > Integer.MAX_VALUE || op2 > Integer.MAX_VALUE
|| op1 < Integer.MIN_VALUE || op2 < Integer.MIN_VALUE) {

3
src/java.base/share/classes/jdk/internal/misc/X-ScopedMemoryAccess.java.template
View file

@ -325,3 +325,6 @@ public class ScopedMemoryAccess {
}
// typed-ops here
// Note: all the accessor methods defined below take advantage of argument type profiling
// (see src/hotspot/share/oops/methodData.cpp) which greatly enhances performance when the same accessor
// method is used repeatedly with different 'base' objects.