Read pointers directly from chunks.

This reduces the amount of Object[] allocated, and thus memory pressure, during startup.
hpi-swa · Oct 14, 2024 · 09245cb · 09245cb
1 parent 0ae803a
commit 09245cb
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Showing 11 changed files with 59 additions and 67 deletions.
diff --git a/src/de.hpi.swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/image/SqueakImageChunk.java b/src/de.hpi.swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/image/SqueakImageChunk.java
@@ -173,25 +173,21 @@ public void setSqueakClass(final ClassObject baseSqueakObject) {
         squeakClass = baseSqueakObject;
     }
 
-    public Object[] getPointers() {
-        if (pointers == null) {
-            final int length = getWordSize();
-            pointers = new Object[length];
-            for (int i = 0; i < length; i++) {
-                pointers[i] = decodePointer(getWord(i));
-            }
-        }
-        return pointers;
+    public Object getPointer(final int index) {
+        return decodePointer(getWord(index));
     }
 
-    public Object[] getPointers(final int end) {
-        if (pointers == null) {
-            pointers = new Object[end];
-            for (int i = 0; i < end; i++) {
-                pointers[i] = decodePointer(getWord(i));
-            }
+    public Object[] getPointers(final int start) {
+        return getPointers(start, getWordSize());
+    }
+
+    public Object[] getPointers(final int start, final int end) {
+        final int numObjects = end - start;
+        final Object[] result = new Object[numObjects];
+        for (int i = 0; i < numObjects; i++) {
+            result[i] = getPointer(start + i);
         }
-        return pointers;
+        return result;
     }
 
     private Object decodePointer(final long ptr) {

diff --git a/src/de.hpi.swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/model/AbstractPointersObject.java b/src/de.hpi.swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/model/AbstractPointersObject.java
@@ -119,16 +119,15 @@ public final void fillin(final SqueakImageChunk chunk) {
         primitiveExtension = layout.getFreshPrimitiveExtension();
         objectExtension = layout.getFreshObjectExtension();
         final AbstractPointersObjectWriteNode writeNode = AbstractPointersObjectWriteNode.getUncached();
-        final Object[] pointers = chunk.getPointers();
         final int instSize = instsize();
         for (int i = 0; i < instSize; i++) {
-            writeNode.execute(null, this, i, pointers[i]);
+            writeNode.execute(null, this, i, chunk.getPointer(i));
         }
-        fillInVariablePart(pointers, instSize);
-        assert size() == pointers.length;
+        fillInVariablePart(chunk, instSize);
+        assert size() == chunk.getWordSize();
     }
 
-    protected abstract void fillInVariablePart(Object[] pointers, int instSize);
+    protected abstract void fillInVariablePart(SqueakImageChunk chunk, int instSize);
 
     public final ObjectLayout getLayout() {
         if (layout == null) {

diff --git a/....swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/model/AbstractVariablePointersObject.java b/....swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/model/AbstractVariablePointersObject.java
@@ -6,10 +6,9 @@
  */
 package de.hpi.swa.trufflesqueak.model;
 
-import java.util.Arrays;
-
 import com.oracle.truffle.api.nodes.Node;
 
+import de.hpi.swa.trufflesqueak.image.SqueakImageChunk;
 import de.hpi.swa.trufflesqueak.image.SqueakImageContext;
 import de.hpi.swa.trufflesqueak.model.layout.ObjectLayout;
 import de.hpi.swa.trufflesqueak.nodes.accessing.SqueakObjectIdentityNode;
@@ -34,8 +33,8 @@ protected AbstractVariablePointersObject(final AbstractVariablePointersObject or
     }
 
     @Override
-    protected void fillInVariablePart(final Object[] pointers, final int instSize) {
-        variablePart = Arrays.copyOfRange(pointers, instSize, pointers.length);
+    protected void fillInVariablePart(final SqueakImageChunk chunk, final int instSize) {
+        variablePart = chunk.getPointers(instSize);
     }
 
     public final void become(final AbstractVariablePointersObject other) {

diff --git a/src/de.hpi.swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/model/ArrayObject.java b/src/de.hpi.swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/model/ArrayObject.java
@@ -77,14 +77,13 @@ public static boolean isLongNilTag(final long value) {
 
     @Override
     public void fillin(final SqueakImageChunk chunk) {
-        final Object[] pointers = chunk.getPointers();
-        final int valuesLength = pointers.length;
+        final int valuesLength = chunk.getWordSize();
         storage = valuesLength;
         if (valuesLength > 0) {
             // Use a fresh write node because uncached node is too generic.
             final ArrayObjectWriteNode writeNode = ArrayObjectWriteNode.create();
             for (int i = 0; i < valuesLength; i++) {
-                writeNode.execute(writeNode, this, i, pointers[i]);
+                writeNode.execute(writeNode, this, i, chunk.getPointer(i));
             }
         }
     }

diff --git a/src/de.hpi.swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/model/BlockClosureObject.java b/src/de.hpi.swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/model/BlockClosureObject.java
@@ -6,8 +6,6 @@
  */
 package de.hpi.swa.trufflesqueak.model;
 
-import java.util.Arrays;
-
 import com.oracle.truffle.api.CompilerAsserts;
 import com.oracle.truffle.api.CompilerDirectives;
 import com.oracle.truffle.api.CompilerDirectives.CompilationFinal;
@@ -72,18 +70,18 @@ public static BlockClosureObject create(final SqueakImageContext image, final Cl
     @Override
     public void fillin(final SqueakImageChunk chunk) {
         CompilerDirectives.transferToInterpreterAndInvalidate();
-        final Object[] pointers = chunk.getPointers();
-        assert pointers.length >= BLOCK_CLOSURE.FIRST_COPIED_VALUE;
-        outerContext = (ContextObject) pointers[BLOCK_CLOSURE.OUTER_CONTEXT];
-        if (pointers[BLOCK_CLOSURE.START_PC_OR_METHOD] instanceof final CompiledCodeObject code) {
+        assert chunk.getWordSize() >= BLOCK_CLOSURE.FIRST_COPIED_VALUE;
+        outerContext = (ContextObject) chunk.getPointer(BLOCK_CLOSURE.OUTER_CONTEXT);
+        final Object startPCOrMethod = chunk.getPointer(BLOCK_CLOSURE.START_PC_OR_METHOD);
+        if (startPCOrMethod instanceof final CompiledCodeObject code) {
             block = code;
-            receiver = pointers[BLOCK_CLOSURE.FULL_RECEIVER];
-            copiedValues = Arrays.copyOfRange(pointers, BLOCK_CLOSURE.FULL_FIRST_COPIED_VALUE, pointers.length);
+            receiver = chunk.getPointer(BLOCK_CLOSURE.FULL_RECEIVER);
+            copiedValues = chunk.getPointers(BLOCK_CLOSURE.FULL_FIRST_COPIED_VALUE);
         } else {
-            startPC = (long) pointers[BLOCK_CLOSURE.START_PC_OR_METHOD];
-            copiedValues = Arrays.copyOfRange(pointers, BLOCK_CLOSURE.FIRST_COPIED_VALUE, pointers.length);
+            startPC = (long) startPCOrMethod;
+            copiedValues = chunk.getPointers(BLOCK_CLOSURE.FIRST_COPIED_VALUE);
         }
-        numArgs = (long) pointers[BLOCK_CLOSURE.ARGUMENT_COUNT];
+        numArgs = (long) chunk.getPointer(BLOCK_CLOSURE.ARGUMENT_COUNT);
     }
 
     public AbstractSqueakObject getOuterContext() {

diff --git a/src/de.hpi.swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/model/ClassObject.java b/src/de.hpi.swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/model/ClassObject.java
@@ -6,8 +6,6 @@
  */
 package de.hpi.swa.trufflesqueak.model;
 
-import java.util.Arrays;
-
 import com.oracle.truffle.api.Assumption;
 import com.oracle.truffle.api.CompilerAsserts;
 import com.oracle.truffle.api.CompilerDirectives;
@@ -257,13 +255,12 @@ public void fillin(final SqueakImageChunk chunk) {
             if (needsSqueakHash() && chunk.getHash() != 0) {
                 setSqueakHash(chunk.getHash());
             }
-            final Object[] chunkPointers = chunk.getPointers();
-            superclass = chunkPointers[CLASS_DESCRIPTION.SUPERCLASS] == NilObject.SINGLETON ? null : (ClassObject) chunkPointers[CLASS_DESCRIPTION.SUPERCLASS];
-            methodDict = (VariablePointersObject) chunkPointers[CLASS_DESCRIPTION.METHOD_DICT];
-            format = (long) chunkPointers[CLASS_DESCRIPTION.FORMAT];
-            instanceVariables = chunkPointers[CLASS_DESCRIPTION.INSTANCE_VARIABLES] == NilObject.SINGLETON ? null : (ArrayObject) chunkPointers[CLASS_DESCRIPTION.INSTANCE_VARIABLES];
-            organization = chunkPointers[CLASS_DESCRIPTION.ORGANIZATION] == NilObject.SINGLETON ? null : (PointersObject) chunkPointers[CLASS_DESCRIPTION.ORGANIZATION];
-            pointers = Arrays.copyOfRange(chunkPointers, CLASS_DESCRIPTION.SIZE, chunkPointers.length);
+            superclass = (ClassObject) NilObject.nilToNull(chunk.getPointer(CLASS_DESCRIPTION.SUPERCLASS));
+            methodDict = (VariablePointersObject) chunk.getPointer(CLASS_DESCRIPTION.METHOD_DICT);
+            format = (long) chunk.getPointer(CLASS_DESCRIPTION.FORMAT);
+            instanceVariables = (ArrayObject) NilObject.nilToNull(chunk.getPointer(CLASS_DESCRIPTION.INSTANCE_VARIABLES));
+            organization = (PointersObject) NilObject.nilToNull(chunk.getPointer(CLASS_DESCRIPTION.ORGANIZATION));
+            pointers = chunk.getPointers(CLASS_DESCRIPTION.SIZE);
         }
     }
 

diff --git a/src/de.hpi.swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/model/CompiledCodeObject.java b/src/de.hpi.swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/model/CompiledCodeObject.java
@@ -316,7 +316,7 @@ public void fillin(final SqueakImageChunk chunk) {
         final long header = chunk.getWord(0) >> SqueakImageConstants.NUM_TAG_BITS;
         numLiterals = CompiledCodeHeaderDecoder.getNumLiterals(header);
         assert literals == null;
-        literals = chunk.getPointers(1 + numLiterals);
+        literals = chunk.getPointers(0, 1 + numLiterals);
         decodeHeader();
         assert bytes == null;
         bytes = Arrays.copyOfRange(chunk.getBytes(), literals.length * SqueakImageConstants.WORD_SIZE, chunk.getBytes().length);

diff --git a/src/de.hpi.swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/model/ContextObject.java b/src/de.hpi.swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/model/ContextObject.java
@@ -111,13 +111,12 @@ public void fillin(final SqueakImageChunk chunk) {
     }
 
     public void fillinContext(final SqueakImageChunk chunk) {
-        final Object[] pointers = chunk.getPointers();
-        size = pointers.length;
+        size = chunk.getWordSize();
         assert size > CONTEXT.TEMP_FRAME_START;
-        final CompiledCodeObject method = (CompiledCodeObject) pointers[CONTEXT.METHOD];
-        final AbstractSqueakObject sender = (AbstractSqueakObject) pointers[CONTEXT.SENDER_OR_NIL];
+        final CompiledCodeObject method = (CompiledCodeObject) chunk.getPointer(CONTEXT.METHOD);
+        final AbstractSqueakObject sender = (AbstractSqueakObject) chunk.getPointer(CONTEXT.SENDER_OR_NIL);
         assert sender != null : "sender should not be null";
-        final Object closureOrNil = pointers[CONTEXT.CLOSURE_OR_NIL];
+        final Object closureOrNil = chunk.getPointer(CONTEXT.CLOSURE_OR_NIL);
         final BlockClosureObject closure;
         final int numArgs;
         final CompiledCodeObject methodOrBlock;
@@ -136,22 +135,22 @@ public void fillinContext(final SqueakImageChunk chunk) {
             }
         }
         final int endArguments = CONTEXT.TEMP_FRAME_START + numArgs;
-        final Object[] arguments = Arrays.copyOfRange(pointers, CONTEXT.RECEIVER, endArguments);
+        final Object[] arguments = chunk.getPointers(CONTEXT.RECEIVER, endArguments);
         final Object[] frameArguments = FrameAccess.newWith(sender, closure, arguments);
         CompilerDirectives.transferToInterpreterAndInvalidate();
         truffleFrame = Truffle.getRuntime().createMaterializedFrame(frameArguments, methodOrBlock.getFrameDescriptor());
         FrameAccess.initializeMarker(truffleFrame);
         FrameAccess.setContext(truffleFrame, this);
-        final Object pc = pointers[CONTEXT.INSTRUCTION_POINTER];
+        final Object pc = chunk.getPointer(CONTEXT.INSTRUCTION_POINTER);
         if (pc == NilObject.SINGLETON) {
             removeInstructionPointer();
         } else {
             setInstructionPointer(MiscUtils.toIntExact((long) pc));
         }
-        final int stackPointer = MiscUtils.toIntExact((long) pointers[CONTEXT.STACKPOINTER]);
+        final int stackPointer = MiscUtils.toIntExact((long) chunk.getPointer(CONTEXT.STACKPOINTER));
         setStackPointer(stackPointer);
         for (int i = 0; i < stackPointer; i++) {
-            atTempPut(i, pointers[CONTEXT.TEMP_FRAME_START + i]);
+            atTempPut(i, chunk.getPointer(CONTEXT.TEMP_FRAME_START + i));
         }
     }
 

diff --git a/src/de.hpi.swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/model/NilObject.java b/src/de.hpi.swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/model/NilObject.java
@@ -31,6 +31,10 @@ public static Object nullToNil(final Object object) {
         return object == null ? SINGLETON : object;
     }
 
+    public static Object nilToNull(final Object object) {
+        return object == SINGLETON ? null : object;
+    }
+
     @Override
     public long getOrCreateSqueakHash() {
         return SQUEAK_HASH;

diff --git a/src/de.hpi.swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/model/PointersObject.java b/src/de.hpi.swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/model/PointersObject.java
@@ -9,6 +9,7 @@
 import com.oracle.truffle.api.CompilerAsserts;
 import com.oracle.truffle.api.nodes.Node;
 
+import de.hpi.swa.trufflesqueak.image.SqueakImageChunk;
 import de.hpi.swa.trufflesqueak.image.SqueakImageContext;
 import de.hpi.swa.trufflesqueak.image.SqueakImageWriter;
 import de.hpi.swa.trufflesqueak.model.layout.ObjectLayout;
@@ -58,9 +59,9 @@ public void setHiddenObject(final Object value) {
     }
 
     @Override
-    protected void fillInVariablePart(final Object[] pointers, final int instSize) {
+    protected void fillInVariablePart(final SqueakImageChunk chunk, final int instSize) {
         // No variable part to fill in
-        assert pointers.length == instSize : "Unexpected number of pointers found for " + this;
+        assert chunk.getWordSize() == instSize : "Unexpected number of pointers found for " + this;
     }
 
     public void become(final PointersObject other) {

diff --git a/....hpi.swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/model/WeakVariablePointersObject.java b/....hpi.swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/model/WeakVariablePointersObject.java
@@ -14,6 +14,7 @@
 import com.oracle.truffle.api.nodes.Node;
 import com.oracle.truffle.api.profiles.InlinedConditionProfile;
 
+import de.hpi.swa.trufflesqueak.image.SqueakImageChunk;
 import de.hpi.swa.trufflesqueak.image.SqueakImageContext;
 import de.hpi.swa.trufflesqueak.image.SqueakImageWriter;
 import de.hpi.swa.trufflesqueak.model.layout.ObjectLayout;
@@ -39,13 +40,12 @@ private WeakVariablePointersObject(final WeakVariablePointersObject original) {
     }
 
     @Override
-    protected void fillInVariablePart(final Object[] pointers, final int instSize) {
-        super.fillInVariablePart(pointers, instSize);
-        for (int i = 0; i < variablePart.length; i++) {
-            final Object value = variablePart[i];
-            if (value instanceof final AbstractSqueakObject o) {
-                variablePart[i] = new WeakRef(o, weakPointersQueue);
-            }
+    protected void fillInVariablePart(final SqueakImageChunk chunk, final int instSize) {
+        final int numVariableSlots = chunk.getWordSize() - instSize;
+        variablePart = new Object[numVariableSlots];
+        for (int i = 0; i < numVariableSlots; i++) {
+            final Object value = chunk.getPointer(instSize + i);
+            variablePart[i] = value instanceof final AbstractSqueakObject o ? new WeakRef(o, weakPointersQueue) : value;
         }
     }