changeset 55637:422fb430bc7b

8227338: templateInterpreter.cpp: copy_table() needs to be safer Reviewed-by: dholmes, eosterlund, sspitsyn, kbarrett
author dcubed
date Wed, 10 Jul 2019 10:18:06 -0400
parents 37cfb64319f6
children 556313991cac
files src/hotspot/share/interpreter/templateInterpreter.cpp
diffstat 1 files changed, 11 insertions(+), 3 deletions(-) [+]
line wrap: on
line diff
--- a/src/hotspot/share/interpreter/templateInterpreter.cpp	Wed Jul 10 14:27:51 2019 +0100
+++ b/src/hotspot/share/interpreter/templateInterpreter.cpp	Wed Jul 10 10:18:06 2019 -0400
@@ -31,7 +31,9 @@
 #include "interpreter/templateTable.hpp"
 #include "logging/log.hpp"
 #include "memory/resourceArea.hpp"
+#include "runtime/safepoint.hpp"
 #include "runtime/timerTrace.hpp"
+#include "utilities/copy.hpp"
 
 #ifndef CC_INTERP
 
@@ -275,11 +277,17 @@
 
 
 //------------------------------------------------------------------------------------------------------------------------
-// Safepoint suppport
+// Safepoint support
 
 static inline void copy_table(address* from, address* to, int size) {
-  // Copy non-overlapping tables. The copy has to occur word wise for MT safety.
-  while (size-- > 0) *to++ = *from++;
+  // Copy non-overlapping tables.
+  if (SafepointSynchronize::is_at_safepoint()) {
+    // Nothing is using the table at a safepoint so skip atomic word copy.
+    Copy::disjoint_words((HeapWord*)from, (HeapWord*)to, (size_t)size);
+  } else {
+    // Use atomic word copy when not at a safepoint for safety.
+    Copy::disjoint_words_atomic((HeapWord*)from, (HeapWord*)to, (size_t)size);
+  }
 }
 
 void TemplateInterpreter::notice_safepoints() {