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https://github.com/openjdk/jdk.git
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6965184: possible races in make_not_entrant_or_zombie
Reviewed-by: kvn
This commit is contained in:
Tom Rodriguez
parent
ae3ddc1514
commit
7533d0caf7
22 changed files with 226 additions and 740 deletions
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@ -397,11 +397,6 @@ void nmethod::add_handler_for_exception_and_pc(Handle exception, address pc, add
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//-------------end of code for ExceptionCache--------------
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void nmFlags::clear() {
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assert(sizeof(nmFlags) == sizeof(int), "using more than one word for nmFlags");
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*(jint*)this = 0;
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}
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int nmethod::total_size() const {
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return
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code_size() +
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@ -419,8 +414,32 @@ const char* nmethod::compile_kind() const {
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return NULL;
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}
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// %%% This variable is no longer used?
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int nmethod::_zombie_instruction_size = NativeJump::instruction_size;
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// Fill in default values for various flag fields
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void nmethod::init_defaults() {
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_state = alive;
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_marked_for_reclamation = 0;
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_has_flushed_dependencies = 0;
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_speculatively_disconnected = 0;
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_has_unsafe_access = 0;
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_has_method_handle_invokes = 0;
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_marked_for_deoptimization = 0;
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_lock_count = 0;
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_stack_traversal_mark = 0;
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_unload_reported = false; // jvmti state
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NOT_PRODUCT(_has_debug_info = false);
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_oops_do_mark_link = NULL;
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_jmethod_id = NULL;
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_osr_link = NULL;
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_scavenge_root_link = NULL;
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_scavenge_root_state = 0;
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_saved_nmethod_link = NULL;
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_compiler = NULL;
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#ifdef HAVE_DTRACE_H
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_trap_offset = 0;
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#endif // def HAVE_DTRACE_H
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}
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nmethod* nmethod::new_native_nmethod(methodHandle method,
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@ -580,25 +599,16 @@ nmethod::nmethod(
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debug_only(No_Safepoint_Verifier nsv;)
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assert_locked_or_safepoint(CodeCache_lock);
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NOT_PRODUCT(_has_debug_info = false);
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_oops_do_mark_link = NULL;
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init_defaults();
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_method = method;
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_entry_bci = InvocationEntryBci;
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_jmethod_id = NULL;
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_osr_link = NULL;
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_scavenge_root_link = NULL;
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_scavenge_root_state = 0;
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_saved_nmethod_link = NULL;
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_compiler = NULL;
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// We have no exception handler or deopt handler make the
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// values something that will never match a pc like the nmethod vtable entry
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_exception_offset = 0;
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_deoptimize_offset = 0;
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_deoptimize_mh_offset = 0;
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_orig_pc_offset = 0;
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#ifdef HAVE_DTRACE_H
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_trap_offset = 0;
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#endif // def HAVE_DTRACE_H
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_stub_offset = data_offset();
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_consts_offset = data_offset();
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_oops_offset = data_offset();
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@ -616,17 +626,9 @@ nmethod::nmethod(
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_exception_cache = NULL;
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_pc_desc_cache.reset_to(NULL);
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flags.clear();
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flags.state = alive;
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_markedForDeoptimization = 0;
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_lock_count = 0;
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_stack_traversal_mark = 0;
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code_buffer->copy_oops_to(this);
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debug_only(verify_scavenge_root_oops());
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CodeCache::commit(this);
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VTune::create_nmethod(this);
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}
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if (PrintNativeNMethods || PrintDebugInfo || PrintRelocations || PrintDependencies) {
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@ -674,15 +676,9 @@ nmethod::nmethod(
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debug_only(No_Safepoint_Verifier nsv;)
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assert_locked_or_safepoint(CodeCache_lock);
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NOT_PRODUCT(_has_debug_info = false);
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_oops_do_mark_link = NULL;
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init_defaults();
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_method = method;
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_entry_bci = InvocationEntryBci;
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_jmethod_id = NULL;
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_osr_link = NULL;
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_scavenge_root_link = NULL;
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_scavenge_root_state = 0;
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_compiler = NULL;
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// We have no exception handler or deopt handler make the
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// values something that will never match a pc like the nmethod vtable entry
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_exception_offset = 0;
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@ -708,17 +704,9 @@ nmethod::nmethod(
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_exception_cache = NULL;
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_pc_desc_cache.reset_to(NULL);
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flags.clear();
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flags.state = alive;
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_markedForDeoptimization = 0;
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_lock_count = 0;
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_stack_traversal_mark = 0;
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code_buffer->copy_oops_to(this);
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debug_only(verify_scavenge_root_oops());
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CodeCache::commit(this);
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VTune::create_nmethod(this);
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}
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if (PrintNMethods || PrintDebugInfo || PrintRelocations || PrintDependencies) {
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@ -783,21 +771,13 @@ nmethod::nmethod(
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debug_only(No_Safepoint_Verifier nsv;)
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assert_locked_or_safepoint(CodeCache_lock);
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NOT_PRODUCT(_has_debug_info = false);
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_oops_do_mark_link = NULL;
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init_defaults();
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_method = method;
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_jmethod_id = NULL;
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_entry_bci = entry_bci;
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_compile_id = compile_id;
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_comp_level = comp_level;
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_entry_bci = entry_bci;
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_osr_link = NULL;
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_scavenge_root_link = NULL;
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_scavenge_root_state = 0;
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_compiler = compiler;
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_orig_pc_offset = orig_pc_offset;
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#ifdef HAVE_DTRACE_H
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_trap_offset = 0;
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#endif // def HAVE_DTRACE_H
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_stub_offset = instructions_offset() + code_buffer->total_offset_of(code_buffer->stubs()->start());
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// Exception handler and deopt handler are in the stub section
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@ -824,15 +804,6 @@ nmethod::nmethod(
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_exception_cache = NULL;
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_pc_desc_cache.reset_to(scopes_pcs_begin());
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flags.clear();
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flags.state = alive;
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_markedForDeoptimization = 0;
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_unload_reported = false; // jvmti state
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_lock_count = 0;
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_stack_traversal_mark = 0;
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// Copy contents of ScopeDescRecorder to nmethod
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code_buffer->copy_oops_to(this);
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debug_info->copy_to(this);
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@ -844,8 +815,6 @@ nmethod::nmethod(
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CodeCache::commit(this);
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VTune::create_nmethod(this);
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// Copy contents of ExceptionHandlerTable to nmethod
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handler_table->copy_to(this);
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nul_chk_table->copy_to(this);
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@ -991,11 +960,6 @@ void nmethod::print_nmethod(bool printmethod) {
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}
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void nmethod::set_version(int v) {
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flags.version = v;
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}
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// Promote one word from an assembly-time handle to a live embedded oop.
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inline void nmethod::initialize_immediate_oop(oop* dest, jobject handle) {
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if (handle == NULL ||
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@ -1142,6 +1106,8 @@ void nmethod::cleanup_inline_caches() {
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// This is a private interface with the sweeper.
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void nmethod::mark_as_seen_on_stack() {
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assert(is_not_entrant(), "must be a non-entrant method");
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// Set the traversal mark to ensure that the sweeper does 2
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// cleaning passes before moving to zombie.
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set_stack_traversal_mark(NMethodSweeper::traversal_count());
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}
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@ -1210,7 +1176,7 @@ void nmethod::make_unloaded(BoolObjectClosure* is_alive, oop cause) {
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// for later on.
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CodeCache::set_needs_cache_clean(true);
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}
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flags.state = unloaded;
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_state = unloaded;
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// Log the unloading.
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log_state_change();
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@ -1236,21 +1202,21 @@ void nmethod::log_state_change() const {
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if (LogCompilation) {
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if (xtty != NULL) {
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ttyLocker ttyl; // keep the following output all in one block
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if (flags.state == unloaded) {
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if (_state == unloaded) {
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xtty->begin_elem("make_unloaded thread='" UINTX_FORMAT "'",
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os::current_thread_id());
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} else {
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xtty->begin_elem("make_not_entrant thread='" UINTX_FORMAT "'%s",
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os::current_thread_id(),
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(flags.state == zombie ? " zombie='1'" : ""));
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(_state == zombie ? " zombie='1'" : ""));
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}
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log_identity(xtty);
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xtty->stamp();
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xtty->end_elem();
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}
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}
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if (PrintCompilation && flags.state != unloaded) {
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print_on(tty, flags.state == zombie ? "made zombie " : "made not entrant ");
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if (PrintCompilation && _state != unloaded) {
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print_on(tty, _state == zombie ? "made zombie " : "made not entrant ");
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tty->cr();
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}
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}
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@ -1261,8 +1227,9 @@ bool nmethod::make_not_entrant_or_zombie(unsigned int state) {
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bool was_alive = false;
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// Make sure the nmethod is not flushed in case of a safepoint in code below.
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// Make sure neither the nmethod nor the method is flushed in case of a safepoint in code below.
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nmethodLocker nml(this);
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methodHandle the_method(method());
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{
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// If the method is already zombie there is nothing to do
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@ -1282,7 +1249,7 @@ bool nmethod::make_not_entrant_or_zombie(unsigned int state) {
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// Enter critical section. Does not block for safepoint.
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MutexLockerEx pl(Patching_lock, Mutex::_no_safepoint_check_flag);
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if (flags.state == state) {
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if (_state == state) {
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// another thread already performed this transition so nothing
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// to do, but return false to indicate this.
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return false;
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@ -1293,17 +1260,37 @@ bool nmethod::make_not_entrant_or_zombie(unsigned int state) {
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if (!is_osr_method() && !is_not_entrant()) {
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NativeJump::patch_verified_entry(entry_point(), verified_entry_point(),
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SharedRuntime::get_handle_wrong_method_stub());
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assert (NativeJump::instruction_size == nmethod::_zombie_instruction_size, "");
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}
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was_alive = is_in_use(); // Read state under lock
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if (is_in_use()) {
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// It's a true state change, so mark the method as decompiled.
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// Do it only for transition from alive.
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inc_decompile_count();
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}
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// Change state
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flags.state = state;
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_state = state;
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// Log the transition once
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log_state_change();
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// Remove nmethod from method.
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// We need to check if both the _code and _from_compiled_code_entry_point
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// refer to this nmethod because there is a race in setting these two fields
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// in methodOop as seen in bugid 4947125.
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// If the vep() points to the zombie nmethod, the memory for the nmethod
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// could be flushed and the compiler and vtable stubs could still call
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// through it.
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if (method() != NULL && (method()->code() == this ||
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method()->from_compiled_entry() == verified_entry_point())) {
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HandleMark hm;
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method()->clear_code();
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}
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if (state == not_entrant) {
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mark_as_seen_on_stack();
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}
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} // leave critical region under Patching_lock
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// When the nmethod becomes zombie it is no longer alive so the
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@ -1311,18 +1298,17 @@ bool nmethod::make_not_entrant_or_zombie(unsigned int state) {
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// state will be flushed later when the transition to zombie
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// happens or they get unloaded.
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if (state == zombie) {
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// zombie only - if a JVMTI agent has enabled the CompiledMethodUnload event
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// and it hasn't already been reported for this nmethod then report it now.
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// (the event may have been reported earilier if the GC marked it for unloading).
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post_compiled_method_unload();
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MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
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flush_dependencies(NULL);
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} else {
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assert(state == not_entrant, "other cases may need to be handled differently");
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}
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if (state == not_entrant) {
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Events::log("Make nmethod not entrant " INTPTR_FORMAT, this);
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} else {
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Events::log("Make nmethod zombie " INTPTR_FORMAT, this);
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}
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if (TraceCreateZombies) {
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tty->print_cr("nmethod <" INTPTR_FORMAT "> code made %s", this, (state == not_entrant) ? "not entrant" : "zombie");
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}
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@ -1330,47 +1316,6 @@ bool nmethod::make_not_entrant_or_zombie(unsigned int state) {
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// Make sweeper aware that there is a zombie method that needs to be removed
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NMethodSweeper::notify(this);
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// not_entrant only stuff
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if (state == not_entrant) {
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mark_as_seen_on_stack();
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}
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if (was_alive) {
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// It's a true state change, so mark the method as decompiled.
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// Do it only for transition from alive.
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inc_decompile_count();
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}
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// zombie only - if a JVMTI agent has enabled the CompiledMethodUnload event
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// and it hasn't already been reported for this nmethod then report it now.
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// (the event may have been reported earilier if the GC marked it for unloading).
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if (state == zombie) {
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post_compiled_method_unload();
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}
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// Zombie only stuff
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if (state == zombie) {
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VTune::delete_nmethod(this);
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}
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// Check whether method got unloaded at a safepoint before this,
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// if so we can skip the flushing steps below
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if (method() == NULL) return true;
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// Remove nmethod from method.
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// We need to check if both the _code and _from_compiled_code_entry_point
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// refer to this nmethod because there is a race in setting these two fields
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// in methodOop as seen in bugid 4947125.
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// If the vep() points to the zombie nmethod, the memory for the nmethod
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// could be flushed and the compiler and vtable stubs could still call
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// through it.
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if (method()->code() == this ||
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method()->from_compiled_entry() == verified_entry_point()) {
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HandleMark hm;
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method()->clear_code();
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}
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return true;
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}
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@ -2109,7 +2054,6 @@ address nmethod::continuation_for_implicit_exception(address pc) {
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void nmethod_init() {
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// make sure you didn't forget to adjust the filler fields
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assert(sizeof(nmFlags) <= 4, "nmFlags occupies more than a word");
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assert(sizeof(nmethod) % oopSize == 0, "nmethod size must be multiple of a word");
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}
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@ -2345,7 +2289,6 @@ void nmethod::print() const {
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tty->print("((nmethod*) "INTPTR_FORMAT ") ", this);
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tty->print(" for method " INTPTR_FORMAT , (address)method());
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tty->print(" { ");
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if (version()) tty->print("v%d ", version());
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if (is_in_use()) tty->print("in_use ");
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if (is_not_entrant()) tty->print("not_entrant ");
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if (is_zombie()) tty->print("zombie ");
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