From 45476eb591d927dbd4afde7a4d29e031139523ad Mon Sep 17 00:00:00 2001
From: Joel Dice <joel.dice@gmail.com>
Date: Wed, 27 Jan 2010 17:46:04 -0700
Subject: [PATCH] fix handling of volatile longs and doubles on PowerPC

We were miscompiling methods which contained getfield, getstatic,
putfield, or putstatic instructions for volatile 64-bit primitives on
32-bit PowerPC due to not noticing that values in registers are clobbered
across function calls.

The solution is to create a separate Compiler::Operand instance for each
object monitor reference before and after the function call to avoid
confusing the compiler.  To avoid duplicate entries in the constant pool,
we add code look for and, if found, reuse any existing entry for the same
constant.
---
 src/compile.cpp | 22 ++++++++++------------
 test/Misc.java  |  4 ++++
 2 files changed, 14 insertions(+), 12 deletions(-)

diff --git a/src/compile.cpp b/src/compile.cpp
index 11bf8fcfcc..00fa33aa15 100644
--- a/src/compile.cpp
+++ b/src/compile.cpp
@@ -1101,6 +1101,12 @@ class Frame {
 
       return c->promiseConstant(p, Compiler::ObjectType);
     } else {
+      for (PoolElement* e = context->objectPool; e; e = e->next) {
+        if (o == e->target) {
+          return c->address(e);
+        }
+      }
+
       context->objectPool = new
         (context->zone.allocate(sizeof(PoolElement)))
         PoolElement(t, o, context->objectPool);
@@ -3555,21 +3561,17 @@ compile(MyThread* t, Frame* initialFrame, unsigned ip,
         }
       }
 
-      Compiler::Operand* fieldOperand = 0;
-
       if ((fieldFlags(t, field) & ACC_VOLATILE)
           and BytesPerWord == 4
           and (fieldCode(t, field) == DoubleField
                or fieldCode(t, field) == LongField))
       {
-        fieldOperand = frame->append(field);
-
         c->call
           (c->constant
            (getThunk(t, acquireMonitorForObjectThunk), Compiler::AddressType),
            0, frame->trace(0, 0), 0, Compiler::VoidType, 2,
            c->register_(t->arch->thread()),
-           fieldOperand);
+           frame->append(field));
       }
 
       switch (fieldCode(t, field)) {
@@ -3652,7 +3654,7 @@ compile(MyThread* t, Frame* initialFrame, unsigned ip,
               Compiler::AddressType),
              0, frame->trace(0, 0), 0, Compiler::VoidType, 2,
              c->register_(t->arch->thread()),
-             fieldOperand);
+             frame->append(field));
         } else {
           c->loadBarrier();
         }
@@ -4571,21 +4573,17 @@ compile(MyThread* t, Frame* initialFrame, unsigned ip,
         table = frame->popObject();
       }
 
-      Compiler::Operand* fieldOperand = 0;
-
       if (fieldFlags(t, field) & ACC_VOLATILE) {
         if (BytesPerWord == 4
             and (fieldCode(t, field) == DoubleField
                  or fieldCode(t, field) == LongField))
         {
-          fieldOperand = frame->append(field);
-
           c->call
             (c->constant
              (getThunk(t, acquireMonitorForObjectThunk),
               Compiler::AddressType),
              0, frame->trace(0, 0), 0, Compiler::VoidType, 2,
-             c->register_(t->arch->thread()), fieldOperand);
+             c->register_(t->arch->thread()), frame->append(field));
         } else {
           c->storeStoreBarrier();
         }
@@ -4663,7 +4661,7 @@ compile(MyThread* t, Frame* initialFrame, unsigned ip,
              (getThunk(t, releaseMonitorForObjectThunk),
               Compiler::AddressType),
              0, frame->trace(0, 0), 0, Compiler::VoidType, 2,
-             c->register_(t->arch->thread()), fieldOperand);
+             c->register_(t->arch->thread()), frame->append(field));
         } else {
           c->storeLoadBarrier();
         }
diff --git a/test/Misc.java b/test/Misc.java
index 8795c9007b..5542ce5cfd 100644
--- a/test/Misc.java
+++ b/test/Misc.java
@@ -5,6 +5,8 @@ public class Misc {
 
   private static volatile int volatileStatic;
 
+  private static volatile long volatileStaticLong;
+
   private final int NonStaticConstant = 42;
 
   private int gamma;
@@ -131,6 +133,7 @@ public class Misc {
       beta = 42;
       alpha = 43;
       volatileStatic = 55;
+      volatileStaticLong = 9L;
       int e = beta;
       int f = alpha;
       m.volatileMember = 23;
@@ -141,6 +144,7 @@ public class Misc {
       expect(alpha == 43);
       expect(m.gamma == 44);
       expect(volatileStatic == 55);
+      expect(volatileStaticLong == 9L);
       expect(m.volatileMember == 27);
     }