From b420616d98704bc6a7ddfb71f2ea9177a71bb35c Mon Sep 17 00:00:00 2001
From: Yiteng Guo <guoyiteng@gmail.com>
Date: Sat, 23 Nov 2019 02:55:04 -0500
Subject: [PATCH] synchronize class loading functions

---
 compiler/src/jlang/util/LLVMUtils.java            | 6 ++++++
 compiler/src/jlang/visit/DesugarSynchronized.java | 6 +++---
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/compiler/src/jlang/util/LLVMUtils.java b/compiler/src/jlang/util/LLVMUtils.java
index ebba177d..40ebfadd 100644
--- a/compiler/src/jlang/util/LLVMUtils.java
+++ b/compiler/src/jlang/util/LLVMUtils.java
@@ -22,6 +22,7 @@
 import java.util.stream.Collectors;
 import java.util.stream.IntStream;
 
+import static jlang.extension.JLangSynchronizedExt.buildMonitorFunc;
 import static org.bytedeco.javacpp.LLVM.*;
 
 /**
@@ -804,6 +805,9 @@ public LLVMValueRef buildGlobalCStr(String str) {
 
     /** Emits a check to ensure that the given class has been loaded by the runtime. */
     public void buildClassLoadCheck(ClassType ct) {
+        // Synchronize the class loading function.
+        buildMonitorFunc(v, Constants.MONITOR_ENTER, LLVMConstNull(v.utils.toLL(v.ts.Object())));
+
         LLVMBasicBlockRef loadClass = v.utils.buildBlock("load.class");
         LLVMBasicBlockRef end = v.utils.buildBlock("continue");
         String classMangled = v.mangler.classObj(ct);
@@ -821,6 +825,8 @@ public void buildClassLoadCheck(ClassType ct) {
         LLVMBuildBr(v.builder, end);
 
         LLVMPositionBuilderAtEnd(v.builder, end);
+
+        buildMonitorFunc(v, Constants.MONITOR_EXIT, LLVMConstNull(v.utils.toLL(v.ts.Object())));
     }
 
     /**
diff --git a/compiler/src/jlang/visit/DesugarSynchronized.java b/compiler/src/jlang/visit/DesugarSynchronized.java
index fe98579a..2e0c6c09 100644
--- a/compiler/src/jlang/visit/DesugarSynchronized.java
+++ b/compiler/src/jlang/visit/DesugarSynchronized.java
@@ -34,9 +34,9 @@ protected Node leaveDesugar(Node n) throws SemanticException {
             //  synchronized(o) {...}
             // To
             //  {
-            //      Object temp = o;
-            //      try { MonitorEnter(o); ... }
-            //      finally { MonitorExit(o); }
+            //      Object syncObj = o;
+            //      try { MonitorEnter(syncObj); ... }
+            //      finally { MonitorExit(syncObj); }
             //  }
             Synchronized node = (Synchronized) n;
             Position pos = node.position();