Remove duplicate CodeCache lookup operation in walkVM (async-profiler#1682)

Author: Baraa-Hasheesh

src/stackWalker.cpp

@@ -258,6 +258,7 @@ int StackWalker::walkVM(void* ucontext, ASGCT_CallFrame* frames, int max_depth,
         }
         prev_sp = sp;
 
+        CodeCache* native_lib = NULL;
         if (CodeHeap::contains(pc)) {
             NMethod* nm = CodeHeap::findNMethod(pc);
             if (nm == NULL) {
@@ -403,7 +404,8 @@ int StackWalker::walkVM(void* ucontext, ASGCT_CallFrame* frames, int max_depth,
                 }
             }
         } else {
-            const char* method_name = profiler->findNativeMethod(pc);
+            native_lib = profiler->findLibraryByAddress(pc);
+            const char* method_name = native_lib != NULL ? native_lib->binarySearch(pc) : NULL;
             char mark;
             if (method_name != NULL && (mark = NativeFunc::mark(method_name)) != 0) {
                 if (mark == MARK_ASYNC_PROFILER && (event_type == MALLOC_SAMPLE || event_type == NATIVE_LOCK_SAMPLE)) {
@@ -421,8 +423,7 @@ int StackWalker::walkVM(void* ucontext, ASGCT_CallFrame* frames, int max_depth,
             fillFrame(frames[depth++], BCI_NATIVE_FRAME, method_name);
         }
 
-        CodeCache* cc = profiler->findLibraryByAddress(pc);
-        FrameDesc* f = cc != NULL ? cc->findFrameDesc(pc) : &FrameDesc::default_frame;
+        FrameDesc* f = native_lib != NULL ? native_lib->findFrameDesc(pc) : &FrameDesc::default_frame;
 
         u8 cfa_reg = (u8)f->cfa;
         int cfa_off = f->cfa >> 8;