Adding CONTEXT_BARRIER to force the PPC context to synchronize.

This is just an annotation right now, as it's not actually needed.

src/xenia/cpu/hir/hir_builder.cc

@@ -1211,6 +1211,10 @@ void HIRBuilder::StoreContext(size_t offset, Value* value) {
   i->src3.value = NULL;
 }
 
+void HIRBuilder::ContextBarrier() {
+  AppendInstr(OPCODE_CONTEXT_BARRIER_info, 0);
+}
+
 Value* HIRBuilder::LoadMmio(cpu::MMIORange* mmio_range, uint32_t address,
                             TypeName type) {
   Instr* i = AppendInstr(OPCODE_LOAD_MMIO_info, 0, AllocValue(type));

src/xenia/cpu/hir/hir_builder.h

@@ -142,6 +142,7 @@ class HIRBuilder {
 
   Value* LoadContext(size_t offset, TypeName type);
   void StoreContext(size_t offset, Value* value);
+  void ContextBarrier();
 
   Value* LoadMmio(cpu::MMIORange* mmio_range, uint32_t address, TypeName type);
   void StoreMmio(cpu::MMIORange* mmio_range, uint32_t address, Value* value);

src/xenia/cpu/hir/opcodes.h

@@ -148,6 +148,7 @@ enum Opcode {
   OPCODE_STORE_LOCAL,
   OPCODE_LOAD_CONTEXT,
   OPCODE_STORE_CONTEXT,
+  OPCODE_CONTEXT_BARRIER,
   OPCODE_LOAD_MMIO,
   OPCODE_STORE_MMIO,
   OPCODE_LOAD,

src/xenia/cpu/hir/opcodes.inl

@@ -213,6 +213,12 @@ DEFINE_OPCODE(
     OPCODE_SIG_X_O_V,
     0)
 
+DEFINE_OPCODE(
+    OPCODE_CONTEXT_BARRIER,
+    "context_barrier",
+    OPCODE_SIG_X,
+    0)
+
 DEFINE_OPCODE(
     OPCODE_LOAD_MMIO,
     "load_mmio",