From bbc5d7fb50a1ed7c549ba7735dac81c21d4c80a6 Mon Sep 17 00:00:00 2001
From: Joel Dice <joel.dice@gmail.com>
Date: Tue, 30 Apr 2013 22:48:43 -0600
Subject: [PATCH] only initialize class when necessary to avoid deadlock

Previously, we would attempt to initialize a class (e.g. call its
static initializer) whenever a method in that class was called, as
well as in any of the cases listed in
http://docs.oracle.com/javase/specs/jls/se7/html/jls-12.html#jls-12.4.

However, the above approach may lead to deadlock in an app which
relies on being able to call non-static methods in parallel with a
static initializer invocation in the same class.  Thus, this commit
ensures that we initialize classes only in the cases defined by the
standard.
---
 src/compile.cpp   | 10 +++-------
 src/interpret.cpp |  8 +++-----
 2 files changed, 6 insertions(+), 12 deletions(-)

diff --git a/src/compile.cpp b/src/compile.cpp
index d218048f40..24737d8344 100644
--- a/src/compile.cpp
+++ b/src/compile.cpp
@@ -4790,9 +4790,7 @@ compile(MyThread* t, Frame* initialFrame, unsigned initialIp,
 
           PROTECT(t, field);
 
-          if (fieldClass(t, field) != methodClass(t, context->method)
-              and classNeedsInit(t, fieldClass(t, field)))
-          {
+          if (classNeedsInit(t, fieldClass(t, field))) {
             c->call
               (c->constant
                (getThunk(t, tryInitClassThunk), Compiler::AddressType),
@@ -5970,9 +5968,7 @@ compile(MyThread* t, Frame* initialFrame, unsigned initialIp,
         if (instruction == putstatic) {
           checkField(t, field, true);
 
-          if (fieldClass(t, field) != methodClass(t, context->method)
-              and classNeedsInit(t, fieldClass(t, field)))
-          {
+          if (classNeedsInit(t, fieldClass(t, field))) {
             PROTECT(t, field);
 
             c->call
@@ -10440,7 +10436,7 @@ compile(MyThread* t, FixedAllocator* allocator, BootContext* bootContext,
 {
   PROTECT(t, method);
 
-  if (bootContext == 0) {
+  if (bootContext == 0 and methodFlags(t, method) & ACC_STATIC) {
     initClass(t, methodClass(t, method));
   }
 
diff --git a/src/interpret.cpp b/src/interpret.cpp
index d222d4c1b5..01192867ee 100644
--- a/src/interpret.cpp
+++ b/src/interpret.cpp
@@ -791,8 +791,6 @@ interpret3(Thread* t, const int base)
     goto throw_;
   }
 
-  initClass(t, methodClass(t, frameMethod(t, frame)));
-
  loop:
   instruction = codeBody(t, code, ip++);
 
@@ -1907,8 +1905,6 @@ interpret3(Thread* t, const int base)
       PROTECT(t, method);
       PROTECT(t, class_);
 
-      initClass(t, class_);
-
       code = findVirtualMethod(t, method, class_);
       goto invoke;
     } else {
@@ -2909,7 +2905,9 @@ invoke(Thread* t, object method)
     class_ = methodClass(t, method);
   }
 
-  initClass(t, class_);
+  if (methodFlags(t, method) & ACC_STATIC) {
+    initClass(t, class_);
+  }
 
   object result = 0;