CompressedKlassPointers::is_encodable shall be callable with -UseCCP

rkennke · Sep 17, 2024 · 612d304 · 612d304
1 parent 352e708
commit 612d304
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Showing 3 changed files with 21 additions and 3 deletions.
diff --git a/src/hotspot/share/oops/compressedKlass.hpp b/src/hotspot/share/oops/compressedKlass.hpp
@@ -249,14 +249,13 @@ class CompressedKlassPointers : public AllStatic {
   // Returns whether the pointer is in the memory region used for encoding compressed
   // class pointers.  This includes CDS.
   static inline bool is_encodable(const void* addr) {
-    check_init(_base);
     // An address can only be encoded if:
     //
     // 1) the address lies within the klass range.
     // 2) It is suitably aligned to 2^encoding_shift. This only really matters for
     //    +UseCompactObjectHeaders, since the encoding shift can be large (max 10 bits -> 1KB).
-    return is_aligned(addr, klass_alignment_in_bytes()) &&
-        (address)addr >= _klass_range_start && (address)addr < _klass_range_end;
+    return (address)addr >= _klass_range_start && (address)addr < _klass_range_end &&
+        is_aligned(addr, klass_alignment_in_bytes());
   }
 
 };

diff --git a/test/hotspot/gtest/oops/test_compressedKlass.cpp b/test/hotspot/gtest/oops/test_compressedKlass.cpp
@@ -50,6 +50,18 @@ TEST_VM(CompressedKlass, basics) {
   }
 }
 
+TEST_VM(CompressedKlass, ccp_off) {
+  if (UseCompressedClassPointers) {
+    return;
+  }
+  ASSERT_EQ(CompressedKlassPointers::klass_range_start(), (address)nullptr);
+  ASSERT_EQ(CompressedKlassPointers::klass_range_end(), (address)nullptr);
+  // We should be able to call CompressedKlassPointers::is_encodable, and it should
+  // always return false
+  ASSERT_FALSE(CompressedKlassPointers::is_encodable((address)0x12345));
+}
+
+
 TEST_VM(CompressedKlass, test_too_low_address) {
   if (!UseCompressedClassPointers) {
     return;

diff --git a/test/hotspot/jtreg/gtest/CompressedKlassGtest.java b/test/hotspot/jtreg/gtest/CompressedKlassGtest.java
@@ -38,6 +38,13 @@
  * @run main/native GTestWrapper --gtest_filter=CompressedKlass* -XX:+UnlockExperimentalVMOptions -XX:-UseCompactObjectHeaders -Xlog:metaspace* -Xmx6g -Xms128m -Xshare:off -XX:CompressedClassSpaceSize=128m
  */
 
+/* @test id=ccp_off
+ * @library /test/lib
+ * @modules java.base/jdk.internal.misc
+ *          java.xml
+ * @run main/native GTestWrapper --gtest_filter=CompressedKlass* -XX:-UseCompressedClassPointers -Xlog:metaspace* -Xmx6g -Xms128m
+ */
+
 /* @test id=use-zero-based-encoding-coh
  * @library /test/lib
  * @modules java.base/jdk.internal.misc