More AGCT cleanup after removing recovery tricks

Author: Baraa-Hasheesh

src/cpuEngine.cpp

@@ -124,9 +124,8 @@ void CpuEngine::signalHandlerJ9(int signo, siginfo_t* siginfo, void* ucontext) {
     if (!_enabled) return;
 
     J9StackTraceNotification notif;
-    StackContext java_ctx;
     notif.num_frames = _cstack == CSTACK_NO ? 0 : _cstack == CSTACK_DWARF
-        ? StackWalker::walkDwarf(ucontext, notif.addr, MAX_J9_NATIVE_FRAMES, &java_ctx)
-        : StackWalker::walkFP(ucontext, notif.addr, MAX_J9_NATIVE_FRAMES, &java_ctx);
+        ? StackWalker::walkDwarf(ucontext, notif.addr, MAX_J9_NATIVE_FRAMES)
+        : StackWalker::walkFP(ucontext, notif.addr, MAX_J9_NATIVE_FRAMES);
     J9StackTraces::checkpoint(_interval, &notif);
 }

src/profiler.cpp

@@ -294,9 +294,9 @@ int Profiler::getNativeTrace(void* ucontext, ASGCT_CallFrame* frames, EventType
     } else if (_cstack == CSTACK_VM) {
         return 0;
     } else if (_cstack == CSTACK_DWARF) {
-        native_frames = StackWalker::walkDwarf(ucontext, callchain, MAX_NATIVE_FRAMES, java_ctx);
+        native_frames = StackWalker::walkDwarf(ucontext, callchain, MAX_NATIVE_FRAMES);
     } else {
-        native_frames = StackWalker::walkFP(ucontext, callchain, MAX_NATIVE_FRAMES, java_ctx);
+        native_frames = StackWalker::walkFP(ucontext, callchain, MAX_NATIVE_FRAMES);
     }
 
     return convertNativeTrace(native_frames, callchain, frames, event_type);
@@ -331,7 +331,7 @@ int Profiler::convertNativeTrace(int native_frames, const void** callchain, ASGC
     return depth;
 }
 
-int Profiler::getJavaTraceAsync(void* ucontext, ASGCT_CallFrame* frames, int max_depth, StackContext* java_ctx) {
+int Profiler::getJavaTraceAsync(void* ucontext, ASGCT_CallFrame* frames, int max_depth) {
     // Workaround for JDK-8132510: it's not safe to call GetEnv() inside a signal handler
     // since JDK 9, so we do it only for threads already registered in ThreadLocalStorage
     VMThread* vm_thread = VMThread::current();
@@ -433,14 +433,14 @@ u64 Profiler::recordSample(void* ucontext, u64 counter, EventType event_type, Ev
         if (_cstack == CSTACK_VM) {
             num_frames += StackWalker::walkVM(ucontext, frames + num_frames, _max_stack_depth, lock_index, _features, event_type);
         } else {
-            num_frames += getJavaTraceAsync(ucontext, frames + num_frames, _max_stack_depth, &java_ctx);
+            num_frames += getJavaTraceAsync(ucontext, frames + num_frames, _max_stack_depth);
         }
     } else if (event_type >= ALLOC_SAMPLE && event_type <= ALLOC_OUTSIDE_TLAB && _alloc_engine == &alloc_tracer) {
         if (VMStructs::hasStackStructs()) {
             StackWalkFeatures no_features{};
             num_frames += StackWalker::walkVM(ucontext, frames + num_frames, _max_stack_depth, lock_index, no_features, event_type);
         } else {
-            num_frames += getJavaTraceAsync(ucontext, frames + num_frames, _max_stack_depth, &java_ctx);
+            num_frames += getJavaTraceAsync(ucontext, frames + num_frames, _max_stack_depth);
         }
     } else {
         // Lock events and instrumentation events can safely call synchronous JVM TI stack walker.

src/profiler.h

@@ -111,7 +111,7 @@ class Profiler {
     const char* asgctError(int code);
     u32 getLockIndex(int tid);
     int getNativeTrace(void* ucontext, ASGCT_CallFrame* frames, EventType event_type, int tid, StackContext* java_ctx);
-    int getJavaTraceAsync(void* ucontext, ASGCT_CallFrame* frames, int max_depth, StackContext* java_ctx);
+    int getJavaTraceAsync(void* ucontext, ASGCT_CallFrame* frames, int max_depth);
     int getJavaTraceJvmti(jvmtiFrameInfo* jvmti_frames, ASGCT_CallFrame* frames, int start_depth, int max_depth);
     void setThreadInfo(int tid, const char* name, jlong java_thread_id);
     void updateThreadName(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread);

src/stackWalker.cpp

@@ -62,7 +62,7 @@ static jmethodID getMethodId(VMMethod* method) {
 }
 
 
-int StackWalker::walkFP(void* ucontext, const void** callchain, int max_depth, StackContext* java_ctx) {
+int StackWalker::walkFP(void* ucontext, const void** callchain, int max_depth) {
     const void* pc;
     uintptr_t fp;
     uintptr_t sp;
@@ -83,8 +83,7 @@ int StackWalker::walkFP(void* ucontext, const void** callchain, int max_depth, S
 
     // Walk until the bottom of the stack or until the first Java frame
     while (depth < max_depth) {
-        if (CodeHeap::contains(pc) && !(depth == 0 && frame.unwindAtomicStub(pc))) {
-            java_ctx->set(pc, sp, fp);
+        if (CodeHeap::contains(pc)) {
             break;
         }
 
@@ -112,7 +111,7 @@ int StackWalker::walkFP(void* ucontext, const void** callchain, int max_depth, S
     return depth;
 }
 
-int StackWalker::walkDwarf(void* ucontext, const void** callchain, int max_depth, StackContext* java_ctx) {
+int StackWalker::walkDwarf(void* ucontext, const void** callchain, int max_depth) {
     const void* pc;
     uintptr_t fp;
     uintptr_t sp;
@@ -134,10 +133,7 @@ int StackWalker::walkDwarf(void* ucontext, const void** callchain, int max_depth
 
     // Walk until the bottom of the stack or until the first Java frame
     while (depth < max_depth) {
-        if (CodeHeap::contains(pc) && !(depth == 0 && frame.unwindAtomicStub(pc))) {
-            // Don't dereference pc as it may point to unreadable memory
-            // frame.adjustSP(page_start, pc, sp);
-            java_ctx->set(pc, sp, fp);
+        if (CodeHeap::contains(pc)) {
             break;
         }
 

src/stackWalker.h

@@ -15,22 +15,13 @@
 class JavaFrameAnchor;
 
 struct StackContext {
-    const void* pc;
-    uintptr_t sp;
-    uintptr_t fp;
     u64 cpu;
-
-    void set(const void* pc, uintptr_t sp, uintptr_t fp) {
-        this->pc = pc;
-        this->sp = sp;
-        this->fp = fp;
-    }
 };
 
 class StackWalker {
   public:
-    static int walkFP(void* ucontext, const void** callchain, int max_depth, StackContext* java_ctx);
-    static int walkDwarf(void* ucontext, const void** callchain, int max_depth, StackContext* java_ctx);
+    static int walkFP(void* ucontext, const void** callchain, int max_depth);
+    static int walkDwarf(void* ucontext, const void** callchain, int max_depth);
     static int walkVM(void* ucontext, ASGCT_CallFrame* frames, int max_depth, int lock_index,
                       StackWalkFeatures features, EventType event_type);