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8352724: Verify bounds for primitive array reads in JVMCI #24200

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8352724: Verify bounds for primitive array reads in JVMCI #24200

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1bfeb51
Verify bounds for primitive array reads.
pecimuth Mar 24, 2025
7475f46
Test reads after last array element in JVMCI.
pecimuth Apr 14, 2025
3661b21
Test array reads that are partially out of bounds.
pecimuth Apr 14, 2025
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18 changes: 17 additions & 1 deletion ...mci/jdk.vm.ci.runtime.test/src/jdk/vm/ci/runtime/test/TestConstantReflectionProvider.java
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Original file line number Diff line number Diff line change
Expand Up @@ -141,11 +141,12 @@ static class ArrayConstants {
}

@Test
public void readAfterLastArrayElementTest() {
public void readOnePastLastArrayElementTest() {
for (ConstantValue cv : readConstants(ArrayConstants.class)) {
if (cv.boxed != null && cv.boxed.getClass().isArray()) {
JavaKind kind = metaAccess.lookupJavaType(cv.value).getComponentType().getJavaKind();
long offset = metaAccess.getArrayBaseOffset(kind) + (long) metaAccess.getArrayIndexScale(kind) * Array.getLength(cv.boxed);
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@dougxc dougxc Apr 14, 2025 •
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If I understand correctly, this tests a read of an element one past the end of the array.
Can you please also add a test for a read that is partially out-of-bounds:

long offset = 1 + metaAccess.getArrayBaseOffset(kind) + (long) metaAccess.getArrayIndexScale(kind) * (Array.getLength(cv.boxed) - 1);

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I added a test for a long read from array[array.index - 1] because adding + 1 would make the read unaligned (which is also not allowed). Please check it out.

// read array[array.length]
assertThrows(IllegalArgumentException.class, () -> {
if (kind == JavaKind.Object) {
constantReflection.getMemoryAccessProvider().readObjectConstant(cv.value, offset);
Expand All @@ -156,4 +157,19 @@ public void readAfterLastArrayElementTest() {
}
}
}

static class IntArrayConstants {
static final int[] INT_ARRAY_CONST = new int[]{0};
}

@Test
public void readPartiallyOutOfBoundsTest() {
for (ConstantValue cv : readConstants(IntArrayConstants.class)) {
JavaKind kind = metaAccess.lookupJavaType(cv.value).getComponentType().getJavaKind();
long offset = metaAccess.getArrayBaseOffset(kind) + (long) metaAccess.getArrayIndexScale(kind) * (Array.getLength(cv.boxed) - 1);
// read a long from array[array.length - 1], which is partially out of bounds
JavaKind accessKind = JavaKind.Long;
assertThrows(IllegalArgumentException.class, () -> constantReflection.getMemoryAccessProvider().readPrimitiveConstant(accessKind, cv.value, offset, accessKind.getBitCount()));
}
}
}