From bbc241babb64be85dbf2ab351c9333ba500f03a1 Mon Sep 17 00:00:00 2001 From: johnc Date: Mon, 7 Jun 2010 17:46:04 -0700 Subject: 6953058: G1: A bigapp crashes with SIGSEGV in compiled code Summary: In C2's G1 post write barrier, the loads of the buffer and index fields from the DirtyCardQueue structure may be moved across a safepoint. Use the current value of "control" in the C2 IR to limit how far these loads can move. Reviewed-by: never, iveresov, kvn --- src/share/vm/opto/graphKit.cpp | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) (limited to 'src/share/vm/opto/graphKit.cpp') diff --git a/src/share/vm/opto/graphKit.cpp b/src/share/vm/opto/graphKit.cpp index 780ac554b..1e710ddb1 100644 --- a/src/share/vm/opto/graphKit.cpp +++ b/src/share/vm/opto/graphKit.cpp @@ -3487,7 +3487,6 @@ void GraphKit::g1_write_barrier_post(Node* oop_store, Node* tls = __ thread(); // ThreadLocalStorage - Node* no_ctrl = NULL; Node* no_base = __ top(); float likely = PROB_LIKELY(0.999); float unlikely = PROB_UNLIKELY(0.999); @@ -3511,10 +3510,10 @@ void GraphKit::g1_write_barrier_post(Node* oop_store, Node* index_adr = __ AddP(no_base, tls, __ ConX(index_offset)); // Now some values - - Node* index = __ load(no_ctrl, index_adr, TypeInt::INT, T_INT, Compile::AliasIdxRaw); - Node* buffer = __ load(no_ctrl, buffer_adr, TypeRawPtr::NOTNULL, T_ADDRESS, Compile::AliasIdxRaw); - + // Use ctrl to avoid hoisting these values past a safepoint, which could + // potentially reset these fields in the JavaThread. + Node* index = __ load(__ ctrl(), index_adr, TypeInt::INT, T_INT, Compile::AliasIdxRaw); + Node* buffer = __ load(__ ctrl(), buffer_adr, TypeRawPtr::NOTNULL, T_ADDRESS, Compile::AliasIdxRaw); // Convert the store obj pointer to an int prior to doing math on it // Must use ctrl to prevent "integerized oop" existing across safepoint -- cgit v1.2.3