[arm64] Use exclusive instructions in exchange

src/arm64/instrument-arm64.cc

Index: src/arm64/instrument-arm64.cc
diff --git a/src/arm64/instrument-arm64.cc b/src/arm64/instrument-arm64.cc
index dad89fe6bffff03ffb695a53e0617c5cd4779e14..bf878c526c221e54ad7afef32eaa9d6e1a36e954 100644
--- a/src/arm64/instrument-arm64.cc
+++ b/src/arm64/instrument-arm64.cc
@@ -61,39 +61,41 @@ typedef struct {
   CounterType type;
 } CounterDescriptor;
 
-
 static const CounterDescriptor kCounterList[] = {
-  {"Instruction", Cumulative},
-
-  {"Move Immediate", Gauge},
-  {"Add/Sub DP", Gauge},
-  {"Logical DP", Gauge},
-  {"Other Int DP", Gauge},
-  {"FP DP", Gauge},
-
-  {"Conditional Select", Gauge},
-  {"Conditional Compare", Gauge},
-
-  {"Unconditional Branch", Gauge},
-  {"Compare and Branch", Gauge},
-  {"Test and Branch", Gauge},
-  {"Conditional Branch", Gauge},
-
-  {"Load Integer", Gauge},
-  {"Load FP", Gauge},
-  {"Load Pair", Gauge},
-  {"Load Literal", Gauge},
-
-  {"Store Integer", Gauge},
-  {"Store FP", Gauge},
-  {"Store Pair", Gauge},
-
-  {"PC Addressing", Gauge},
-  {"Other", Gauge},
-  {"SP Adjust", Gauge},
+    {"Instruction", Cumulative},
+
+    {"Move Immediate", Gauge},
+    {"Add/Sub DP", Gauge},
+    {"Logical DP", Gauge},
+    {"Other Int DP", Gauge},
+    {"FP DP", Gauge},
+
+    {"Conditional Select", Gauge},
+    {"Conditional Compare", Gauge},
+
+    {"Unconditional Branch", Gauge},
+    {"Compare and Branch", Gauge},
+    {"Test and Branch", Gauge},
+    {"Conditional Branch", Gauge},
+
+    {"Load Integer", Gauge},
+    {"Load FP", Gauge},
+    {"Load Pair", Gauge},
+    {"Load Literal", Gauge},
+    {"Load Exclusive", Gauge},
+    {"Load Acquire", Gauge},
+
+    {"Store Integer", Gauge},
+    {"Store FP", Gauge},
+    {"Store Pair", Gauge},
+    {"Store Exclusive", Gauge},
+    {"Store Release", Gauge},
+
+    {"PC Addressing", Gauge},
+    {"Other", Gauge},
+    {"SP Adjust", Gauge},
 };
 
-
 Instrument::Instrument(const char* datafile, uint64_t sample_period)
     : output_stream_(stderr), sample_period_(sample_period) {
 
@@ -429,6 +431,29 @@ void Instrument::VisitLoadStoreUnsignedOffset(Instruction* instr) {
   InstrumentLoadStore(instr);
 }
 
+void Instrument::VisitLoadStoreExclusive(Instruction* instr) {
+  Update();
+  static Counter* load_counter = GetCounter("Load Exclusive");
+  static Counter* store_counter = GetCounter("Store Exclusive");
+
+  switch (instr->Mask(LoadStoreAcquireReleaseMask)) {
+    case LDXRB:   // Fall-through.
+    case LDXRH:   // Fall-through.
+    case LDXR_w:  // Fall-through.
+    case LDXR_x:
+      load_counter->Increment();
+      break;
+    case STXRB:   // Fall-through.
+    case STXRH:   // Fall-through.
+    case STXR_w:  // Fall-through.
+    case STXR_x:
+      store_counter->Increment();
+      break;
+    default:
+      UNREACHABLE();
+  }
+}
+
 void Instrument::VisitLoadStoreAcquireRelease(Instruction* instr) {
   Update();
   static Counter* load_counter = GetCounter("Load Acquire");