Fix issues with Arm's use of embedded constant pools

src/arm/frames-arm.h

Index: src/arm/frames-arm.h
diff --git a/src/arm/frames-arm.h b/src/arm/frames-arm.h
index ea621c965b47e9322b7f6d0ddcb0eefb10db9c20..b9ffdd0712a9c46120c25bafc86bbf274c6bec9e 100644
--- a/src/arm/frames-arm.h
+++ b/src/arm/frames-arm.h
@@ -66,11 +66,23 @@ const int kNumDoubleCalleeSaved = 8;
 // TODO(regis): Only 8 registers may actually be sufficient. Revisit.
 const int kNumSafepointRegisters = 16;
 
+// The embedded constant pool pointer (r8/pp) is not included in the safepoint
+// since it is not tagged.  This register is preserved in the stack frame where
+// its value will be updated if GC code movement occurs.  Including it in the
+// safepoint (where it will not be relocated) would cause a stale value to be
+// restored.
+const RegList kConstantPointerRegMask =
+    FLAG_enable_embedded_constant_pool ? (1 << 8) : 0;
+const int kNumConstantPoolPointerReg =
+    FLAG_enable_embedded_constant_pool ? 1 : 0;
+
 // Define the list of registers actually saved at safepoints.
 // Note that the number of saved registers may be smaller than the reserved
 // space, i.e. kNumSafepointSavedRegisters <= kNumSafepointRegisters.
-const RegList kSafepointSavedRegisters = kJSCallerSaved | kCalleeSaved;
-const int kNumSafepointSavedRegisters = kNumJSCallerSaved + kNumCalleeSaved;
+const RegList kSafepointSavedRegisters =
+    kJSCallerSaved | (kCalleeSaved & ~kConstantPointerRegMask);
+const int kNumSafepointSavedRegisters =
+    kNumJSCallerSaved + kNumCalleeSaved - kNumConstantPoolPointerReg;
 
 // ----------------------------------------------------