Changes to support dprof and Observatory profiler UIs

runtime/vm/native_symbol_macos.cc

Index: runtime/vm/native_symbol_macos.cc
diff --git a/runtime/vm/native_symbol_macos.cc b/runtime/vm/native_symbol_macos.cc
index 4de33cef80b62eb1b3c5cfa9f91a6ee4990fadcc..83169e642102b39214835bea7407e71b32c5a0a2 100644
--- a/runtime/vm/native_symbol_macos.cc
+++ b/runtime/vm/native_symbol_macos.cc
@@ -21,7 +21,7 @@ void NativeSymbolResolver::ShutdownOnce() {
 }
 
 
-char* NativeSymbolResolver::LookupSymbolName(uintptr_t pc) {
+char* NativeSymbolResolver::LookupSymbolName(uintptr_t pc, uintptr_t* start) {
   Dl_info info;
   int r = dladdr(reinterpret_cast<void*>(pc), &info);
   if (r == 0) {
@@ -30,6 +30,9 @@ char* NativeSymbolResolver::LookupSymbolName(uintptr_t pc) {
   if (info.dli_sname == NULL) {
     return NULL;
   }
+  if (start != NULL) {
+    *start = reinterpret_cast<uintptr_t>(info.dli_saddr);
+  }
   int status;
   char* demangled = abi::__cxa_demangle(info.dli_sname, NULL, NULL, &status);
   if (status == 0) {