archive/jdk
1
0
Fork 0
mirror of https://github.com/openjdk/jdk.git synced 2025-08-28 07:14:30 +02:00
Code Issues Projects Releases Packages Wiki Activity Actions

8266497: Remove unnecessary EMCP liveness indication

Browse source 
Reviewed-by: iklam, dholmes, sspitsyn
This commit is contained in:
Coleen Phillimore 2021-05-05 12:59:39 +00:00
parent 6ba911d64e
commit a05e8e2422
4 changed files with 14 additions and 69 deletions
Download patch file Download diff file Expand all files Collapse all files

47
src/hotspot/share/oops/instanceKlass.cpp
View file

@ -3989,30 +3989,6 @@ void InstanceKlass::purge_previous_version_list() {
_has_previous_versions = true;
}
// At least one method is live in this previous version.
// Reset dead EMCP methods not to get breakpoints.
// All methods are deallocated when all of the methods for this class are no
// longer running.
Array<Method*>* method_refs = pv_node->methods();
if (method_refs != NULL) {
log_trace(redefine, class, iklass, purge)("previous methods length=%d", method_refs->length());
for (int j = 0; j < method_refs->length(); j++) {
Method* method = method_refs->at(j);
if (!method->on_stack()) {
// no breakpoints for non-running methods
if (method->is_running_emcp()) {
method->set_running_emcp(false);
}
} else {
assert (method->is_obsolete() || method->is_running_emcp(),
"emcp method cannot run after emcp bit is cleared");
log_trace(redefine, class, iklass, purge)
("purge: %s(%s): prev method @%d in version @%d is alive",
method->name()->as_C_string(), method->signature()->as_C_string(), j, version);
}
}
}
// next previous version
last = pv_node;
pv_node = pv_node->previous_versions();
@ -4112,29 +4088,6 @@ void InstanceKlass::add_previous_version(InstanceKlass* scratch_class,
return;
}
if (emcp_method_count != 0) {
// At least one method is still running, check for EMCP methods
for (int i = 0; i < old_methods->length(); i++) {
Method* old_method = old_methods->at(i);
if (!old_method->is_obsolete() && old_method->on_stack()) {
// if EMCP method (not obsolete) is on the stack, mark as EMCP so that
// we can add breakpoints for it.
// We set the method->on_stack bit during safepoints for class redefinition
// and use this bit to set the is_running_emcp bit.
// After the safepoint, the on_stack bit is cleared and the running emcp
// method may exit. If so, we would set a breakpoint in a method that
// is never reached, but this won't be noticeable to the programmer.
old_method->set_running_emcp(true);
log_trace(redefine, class, iklass, add)
("EMCP method %s is on_stack " INTPTR_FORMAT, old_method->name_and_sig_as_C_string(), p2i(old_method));
} else if (!old_method->is_obsolete()) {
log_trace(redefine, class, iklass, add)
("EMCP method %s is NOT on_stack " INTPTR_FORMAT, old_method->name_and_sig_as_C_string(), p2i(old_method));
}
}
}
// Add previous version if any methods are still running.
// Set has_previous_version flag for processing during class unloading.
_has_previous_versions = true;