8340392: Handle OopStorage in location decoder

Reviewed-by: kbarrett, dholmes

Author: shipilev

src/hotspot/share/gc/shared/oopStorage.cpp

@@ -1135,6 +1135,26 @@ void OopStorage::BasicParState::report_num_dead() const {
 
 const char* OopStorage::name() const { return _name; }
 
+bool OopStorage::print_containing(const oop* addr, outputStream* st) {
+  if (addr != nullptr) {
+    Block* block = find_block_or_null(addr);
+    if (block != nullptr && block->print_containing(addr, st)) {
+      st->print(" in oop storage \"%s\"", name());
+      return true;
+    }
+  }
+  return false;
+}
+
+bool OopStorage::Block::print_containing(const oop* addr, outputStream* st) {
+  if (contains(addr)) {
+    st->print(PTR_FORMAT " is a pointer %u/%zu into block %zu",
+              p2i(addr), get_index(addr), ARRAY_SIZE(_data), _active_index);
+    return true;
+  }
+  return false;
+}
+
 #ifndef PRODUCT
 
 void OopStorage::print_on(outputStream* st) const {

src/hotspot/share/gc/shared/oopStorage.hpp

@@ -213,6 +213,7 @@ class OopStorage : public CHeapObjBase {
   // Debugging and logging support.
   const char* name() const;
   void print_on(outputStream* st) const PRODUCT_RETURN;
+  bool print_containing(const oop* addr, outputStream* st);
 
   // Provides access to storage internals, for unit testing.
   // Declare, but not define, the public class OopStorage::TestAccess.

src/hotspot/share/gc/shared/oopStorage.inline.hpp

@@ -196,6 +196,8 @@ class OopStorage::Block /* No base class, to avoid messing up alignment. */ {
 
   template<typename F> bool iterate(F f);
   template<typename F> bool iterate(F f) const;
+
+  bool print_containing(const oop* addr, outputStream* st);
 }; // class Block
 
 inline OopStorage::Block* OopStorage::AllocationList::head() {

src/hotspot/share/gc/shared/oopStorageSet.cpp

@@ -82,6 +82,23 @@ template OopStorage* OopStorageSet::get_storage(StrongId);
 template OopStorage* OopStorageSet::get_storage(WeakId);
 template OopStorage* OopStorageSet::get_storage(Id);
 
+bool OopStorageSet::print_containing(const void* addr, outputStream* st) {
+  if (addr != nullptr) {
+    const void* aligned_addr = align_down(addr, alignof(oop));
+    for (OopStorage* storage : Range<Id>()) {
+      if (storage->print_containing((oop*) aligned_addr, st)) {
+        if (aligned_addr != addr) {
+          st->print_cr(" (unaligned)");
+        } else {
+          st->cr();
+        }
+        return true;
+      }
+    }
+  }
+  return false;
+}
+
 #ifdef ASSERT
 
 void OopStorageSet::verify_initialized(uint index) {

src/hotspot/share/gc/shared/oopStorageSet.hpp

@@ -26,6 +26,7 @@
 #define SHARE_GC_SHARED_OOPSTORAGESET_HPP
 
 #include "nmt/memTag.hpp"
+#include "oops/oop.hpp"
 #include "utilities/debug.hpp"
 #include "utilities/enumIterator.hpp"
 #include "utilities/globalDefinitions.hpp"
@@ -89,6 +90,8 @@ class OopStorageSet : public AllStatic {
   template <typename Closure>
   static void strong_oops_do(Closure* cl);
 
+  // Debugging: print location info, if in storage.
+  static bool print_containing(const void* addr, outputStream* st);
 };
 
 ENUMERATOR_VALUE_RANGE(OopStorageSet::StrongId,

src/hotspot/share/runtime/os.cpp

@@ -32,6 +32,7 @@
 #include "code/codeCache.hpp"
 #include "code/vtableStubs.hpp"
 #include "gc/shared/gcVMOperations.hpp"
+#include "gc/shared/oopStorageSet.hpp"
 #include "interpreter/interpreter.hpp"
 #include "jvm.h"
 #include "logging/log.hpp"
@@ -1317,6 +1318,11 @@ void os::print_location(outputStream* st, intptr_t x, bool verbose) {
   }
 #endif
 
+  // Ask if any OopStorage knows about this address.
+  if (OopStorageSet::print_containing(addr, st)) {
+    return;
+  }
+
   // Still nothing? If NMT is enabled, we can ask what it thinks...
   if (MemTracker::print_containing_region(addr, st)) {
     return;

test/hotspot/gtest/gc/shared/test_oopStorageSet.cpp

@@ -23,15 +23,21 @@
  */
 
 #include "precompiled.hpp"
-#include "gc/shared/oopStorage.hpp"
+#include "gc/shared/oopStorage.inline.hpp"
 #include "gc/shared/oopStorageSet.hpp"
 #include "memory/allocation.inline.hpp"
+#include "runtime/interfaceSupport.inline.hpp"
+#include "runtime/vmOperations.hpp"
+#include "runtime/vmThread.hpp"
 #include "utilities/debug.hpp"
 #include "utilities/enumIterator.hpp"
 #include "utilities/globalDefinitions.hpp"
 #include "utilities/macros.hpp"
 #include "unittest.hpp"
 
+using ::testing::HasSubstr;
+using ::testing::Not;
+
 class OopStorageSetTest : public ::testing::Test {
 protected:
   // Returns index of s in storages, or size if not found.
@@ -83,6 +89,8 @@ class OopStorageSetTest : public ::testing::Test {
       EnumRange<OopStorageSet::Id>(),
       &OopStorageSet::fill_all);
   }
+
+  class VM_PrintAtSafepoint;
 };
 
 TEST_VM_F(OopStorageSetTest, strong_iteration) {
@@ -96,3 +104,77 @@ TEST_VM_F(OopStorageSetTest, weak_iteration) {
 TEST_VM_F(OopStorageSetTest, all_iteration) {
   test_all_iteration();
 }
+
+class OopStorageSetTest::VM_PrintAtSafepoint : public VM_GTestExecuteAtSafepoint {
+private:
+  class PrintContainingClosure : public Closure {
+    public:
+      void do_oop(oop* addr) {
+        // Direct slot hit.
+        {
+          stringStream ss;
+          bool printed = OopStorageSet::print_containing(addr, &ss);
+          ASSERT_TRUE(printed);
+          ASSERT_THAT(ss.freeze(), HasSubstr("is a pointer"));
+          ASSERT_THAT(ss.freeze(), HasSubstr("into block"));
+          ASSERT_THAT(ss.freeze(), HasSubstr("in oop storage"));
+          ASSERT_THAT(ss.freeze(), Not(HasSubstr("(unaligned)")));
+        }
+
+        // Unaligned pointer to adjacent slot, should still be in oop storage range.
+        {
+          char* unaligned_addr = (char*)addr + 1;
+          stringStream ss;
+          bool printed = OopStorageSet::print_containing(unaligned_addr, &ss);
+          ASSERT_TRUE(printed);
+          ASSERT_THAT(ss.freeze(), HasSubstr("is a pointer"));
+          ASSERT_THAT(ss.freeze(), HasSubstr("into block"));
+          ASSERT_THAT(ss.freeze(), HasSubstr("in oop storage"));
+          ASSERT_THAT(ss.freeze(), HasSubstr("(unaligned)"));
+        }
+      }
+  };
+
+public:
+  void doit() {
+    PrintContainingClosure cl;
+    for (OopStorage* storage : OopStorageSet::Range<OopStorageSet::Id>()) {
+      storage->oops_do(&cl);
+    }
+  }
+};
+
+TEST_VM_F(OopStorageSetTest, print_containing) {
+  // nullptrs print nothing
+  {
+    stringStream ss;
+    bool printed = OopStorageSet::print_containing(nullptr, &ss);
+    ASSERT_FALSE(printed);
+    EXPECT_STREQ("", ss.freeze());
+  }
+
+  // Goofy values print nothing: unaligned out of storage pointer.
+  {
+    stringStream ss;
+    bool printed = OopStorageSet::print_containing((char*)0x1, &ss);
+    ASSERT_FALSE(printed);
+    EXPECT_STREQ("", ss.freeze());
+  }
+
+  // Goofy values print nothing: aligned out of storage pointer.
+  {
+    stringStream ss;
+    bool printed = OopStorageSet::print_containing((char*)alignof(oop), &ss);
+    ASSERT_FALSE(printed);
+    EXPECT_STREQ("", ss.freeze());
+  }
+
+  // All slot addresses should print well.
+  {
+    VM_PrintAtSafepoint op;
+    {
+      ThreadInVMfromNative invm(JavaThread::current());
+      VMThread::execute(&op);
+    }
+  }
+}