Partial fragment deoptimization
We used to do either single frame deoptimization, or full fragment
deoptimization which deoptimizes all the frames in a fragment.
This change allows some methods to be not deoptimizeable, likely due
to some kind of optimization. So we need another deoptimization mode
that unwinds partial fragment. Deoptimizations are now generalized into
either full or partial fragment. A full fragment deoptimization will
deopt all frames in the fragment, and then returns from the invoke stub
to enter interpreter. A partial fragment deoptimization will deopt a
single frame, or all frames up to the method that's not deoptimizeable,
and then jumps to the interpreter bridge.
Currently code not deoptimizeable is the code in boot image since the
code may not be compiled with debuggable flag.
Bug: 28769520
Change-Id: I875c694791cc8ebd5121abcd92ce7b0db95aca38
diff --git a/runtime/thread.cc b/runtime/thread.cc
index 1d7e065..f1f4a12 100644
--- a/runtime/thread.cc
+++ b/runtime/thread.cc
@@ -55,6 +55,7 @@
#include "mirror/object_array-inl.h"
#include "mirror/stack_trace_element.h"
#include "monitor.h"
+#include "nth_caller_visitor.h"
#include "oat_quick_method_header.h"
#include "object_lock.h"
#include "quick_exception_handler.h"
@@ -84,6 +85,8 @@
namespace art {
+extern "C" NO_RETURN void artDeoptimize(Thread* self);
+
bool Thread::is_started_ = false;
pthread_key_t Thread::pthread_key_self_;
ConditionVariable* Thread::resume_cond_ = nullptr;
@@ -270,7 +273,6 @@
StackedShadowFrameRecord* record = tlsPtr_.stacked_shadow_frame_record;
if (must_be_present) {
DCHECK(record != nullptr);
- DCHECK_EQ(record->GetType(), type);
} else {
if (record == nullptr || record->GetType() != type) {
return nullptr;
@@ -2583,38 +2585,42 @@
// Get exception from thread.
mirror::Throwable* exception = GetException();
CHECK(exception != nullptr);
- bool is_deoptimization = (exception == GetDeoptimizationException());
- if (!is_deoptimization) {
- // This is a real exception: let the instrumentation know about it.
- instrumentation::Instrumentation* instrumentation = Runtime::Current()->GetInstrumentation();
- if (instrumentation->HasExceptionCaughtListeners() &&
- IsExceptionThrownByCurrentMethod(exception)) {
- // Instrumentation may cause GC so keep the exception object safe.
- StackHandleScope<1> hs(this);
- HandleWrapper<mirror::Throwable> h_exception(hs.NewHandleWrapper(&exception));
- instrumentation->ExceptionCaughtEvent(this, exception);
- }
- // Does instrumentation need to deoptimize the stack?
- // Note: we do this *after* reporting the exception to instrumentation in case it
- // now requires deoptimization. It may happen if a debugger is attached and requests
- // new events (single-step, breakpoint, ...) when the exception is reported.
- is_deoptimization = Dbg::IsForcedInterpreterNeededForException(this);
- if (is_deoptimization) {
+ if (exception == GetDeoptimizationException()) {
+ artDeoptimize(this);
+ UNREACHABLE();
+ }
+
+ // This is a real exception: let the instrumentation know about it.
+ instrumentation::Instrumentation* instrumentation = Runtime::Current()->GetInstrumentation();
+ if (instrumentation->HasExceptionCaughtListeners() &&
+ IsExceptionThrownByCurrentMethod(exception)) {
+ // Instrumentation may cause GC so keep the exception object safe.
+ StackHandleScope<1> hs(this);
+ HandleWrapper<mirror::Throwable> h_exception(hs.NewHandleWrapper(&exception));
+ instrumentation->ExceptionCaughtEvent(this, exception);
+ }
+ // Does instrumentation need to deoptimize the stack?
+ // Note: we do this *after* reporting the exception to instrumentation in case it
+ // now requires deoptimization. It may happen if a debugger is attached and requests
+ // new events (single-step, breakpoint, ...) when the exception is reported.
+ if (Dbg::IsForcedInterpreterNeededForException(this)) {
+ NthCallerVisitor visitor(this, 0, false);
+ visitor.WalkStack();
+ if (Runtime::Current()->IsDeoptimizeable(visitor.caller_pc)) {
// Save the exception into the deoptimization context so it can be restored
// before entering the interpreter.
PushDeoptimizationContext(
JValue(), /*is_reference */ false, /* from_code */ false, exception);
+ artDeoptimize(this);
+ UNREACHABLE();
}
}
+
// Don't leave exception visible while we try to find the handler, which may cause class
// resolution.
ClearException();
- QuickExceptionHandler exception_handler(this, is_deoptimization);
- if (is_deoptimization) {
- exception_handler.DeoptimizeStack();
- } else {
- exception_handler.FindCatch(exception);
- }
+ QuickExceptionHandler exception_handler(this, false);
+ exception_handler.FindCatch(exception);
exception_handler.UpdateInstrumentationStack();
exception_handler.DoLongJump();
}
@@ -3024,7 +3030,6 @@
mirror::Throwable* pending_exception = nullptr;
bool from_code = false;
PopDeoptimizationContext(result, &pending_exception, &from_code);
- CHECK(!from_code) << "Deoptimizing from code should be done with single frame deoptimization";
SetTopOfStack(nullptr);
SetTopOfShadowStack(shadow_frame);