8227745: Enable Escape Analysis for Better Performance in the Presence of JVMTI Agents

8233915: JVMTI FollowReferences: Java Heap Leak not found because of C2 Scalar Replacement

Reviewed-by: mdoerr, goetz, sspitsyn, kvn

Author: reinrich

src/hotspot/share/c1/c1_IR.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1999, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1999, 2020, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -244,7 +244,11 @@ class IRScopeDebugInfo: public CompilationResourceObj {
     bool reexecute = topmost ? should_reexecute() : false;
     bool return_oop = false; // This flag will be ignored since it used only for C2 with escape analysis.
     bool rethrow_exception = false;
-    recorder->describe_scope(pc_offset, methodHandle(), scope()->method(), bci(), reexecute, rethrow_exception, is_method_handle_invoke, return_oop, locvals, expvals, monvals);
+    bool has_ea_local_in_scope = false;
+    bool arg_escape = false;
+    recorder->describe_scope(pc_offset, methodHandle(), scope()->method(), bci(),
+                             reexecute, rethrow_exception, is_method_handle_invoke, return_oop,
+                             has_ea_local_in_scope, arg_escape, locvals, expvals, monvals);
   }
 };
 

src/hotspot/share/ci/ciEnv.cpp

@@ -242,6 +242,7 @@ bool ciEnv::cache_jvmti_state() {
   _jvmti_can_post_on_exceptions         = JvmtiExport::can_post_on_exceptions();
   _jvmti_can_pop_frame                  = JvmtiExport::can_pop_frame();
   _jvmti_can_get_owned_monitor_info     = JvmtiExport::can_get_owned_monitor_info();
+  _jvmti_can_walk_any_space             = JvmtiExport::can_walk_any_space();
   return _task != NULL && _task->method()->is_old();
 }
 
@@ -271,6 +272,10 @@ bool ciEnv::jvmti_state_changed() const {
       JvmtiExport::can_get_owned_monitor_info()) {
     return true;
   }
+  if (!_jvmti_can_walk_any_space &&
+      JvmtiExport::can_walk_any_space()) {
+    return true;
+  }
 
   return false;
 }

src/hotspot/share/ci/ciEnv.hpp

@@ -74,6 +74,7 @@ class ciEnv : StackObj {
   bool  _jvmti_can_post_on_exceptions;
   bool  _jvmti_can_pop_frame;
   bool  _jvmti_can_get_owned_monitor_info; // includes can_get_owned_monitor_stack_depth_info
+  bool  _jvmti_can_walk_any_space;
 
   // Cache DTrace flags
   bool  _dtrace_extended_probes;
@@ -349,6 +350,7 @@ class ciEnv : StackObj {
   bool  jvmti_can_hotswap_or_post_breakpoint() const { return _jvmti_can_hotswap_or_post_breakpoint; }
   bool  jvmti_can_post_on_exceptions()         const { return _jvmti_can_post_on_exceptions; }
   bool  jvmti_can_get_owned_monitor_info()     const { return _jvmti_can_get_owned_monitor_info; }
+  bool  jvmti_can_walk_any_space()             const { return _jvmti_can_walk_any_space; }
 
   // Cache DTrace flags
   void  cache_dtrace_flags();

src/hotspot/share/code/compiledMethod.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2015, 2020, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -293,17 +293,13 @@ void CompiledMethod::verify_oop_relocations() {
 ScopeDesc* CompiledMethod::scope_desc_at(address pc) {
   PcDesc* pd = pc_desc_at(pc);
   guarantee(pd != NULL, "scope must be present");
-  return new ScopeDesc(this, pd->scope_decode_offset(),
-                       pd->obj_decode_offset(), pd->should_reexecute(), pd->rethrow_exception(),
-                       pd->return_oop());
+  return new ScopeDesc(this, pd);
 }
 
 ScopeDesc* CompiledMethod::scope_desc_near(address pc) {
   PcDesc* pd = pc_desc_near(pc);
   guarantee(pd != NULL, "scope must be present");
-  return new ScopeDesc(this, pd->scope_decode_offset(),
-                       pd->obj_decode_offset(), pd->should_reexecute(), pd->rethrow_exception(),
-                       pd->return_oop());
+  return new ScopeDesc(this, pd);
 }
 
 address CompiledMethod::oops_reloc_begin() const {

src/hotspot/share/code/debugInfoRec.cpp

@@ -288,6 +288,8 @@ void DebugInformationRecorder::describe_scope(int         pc_offset,
                                               bool        rethrow_exception,
                                               bool        is_method_handle_invoke,
                                               bool        return_oop,
+                                              bool        has_ea_local_in_scope,
+                                              bool        arg_escape,
                                               DebugToken* locals,
                                               DebugToken* expressions,
                                               DebugToken* monitors) {
@@ -304,6 +306,8 @@ void DebugInformationRecorder::describe_scope(int         pc_offset,
   last_pd->set_rethrow_exception(rethrow_exception);
   last_pd->set_is_method_handle_invoke(is_method_handle_invoke);
   last_pd->set_return_oop(return_oop);
+  last_pd->set_has_ea_local_in_scope(has_ea_local_in_scope);
+  last_pd->set_arg_escape(arg_escape);
 
   // serialize sender stream offest
   stream()->write_int(sender_stream_offset);

src/hotspot/share/code/debugInfoRec.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1998, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1998, 2020, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -105,6 +105,8 @@ class DebugInformationRecorder: public ResourceObj {
                       bool        rethrow_exception = false,
                       bool        is_method_handle_invoke = false,
                       bool        return_oop = false,
+                      bool        has_ea_local_in_scope = false,
+                      bool        arg_escape = false,
                       DebugToken* locals      = NULL,
                       DebugToken* expressions = NULL,
                       DebugToken* monitors    = NULL);

src/hotspot/share/code/nmethod.cpp

@@ -2419,9 +2419,7 @@ void nmethod::verify_interrupt_point(address call_site) {
 
   PcDesc* pd = pc_desc_at(nativeCall_at(call_site)->return_address());
   assert(pd != NULL, "PcDesc must exist");
-  for (ScopeDesc* sd = new ScopeDesc(this, pd->scope_decode_offset(),
-                                     pd->obj_decode_offset(), pd->should_reexecute(), pd->rethrow_exception(),
-                                     pd->return_oop());
+  for (ScopeDesc* sd = new ScopeDesc(this, pd);
        !sd->is_top(); sd = sd->sender()) {
     sd->verify();
   }
@@ -3056,9 +3054,7 @@ const char* nmethod::reloc_string_for(u_char* begin, u_char* end) {
 ScopeDesc* nmethod::scope_desc_in(address begin, address end) {
   PcDesc* p = pc_desc_near(begin+1);
   if (p != NULL && p->real_pc(this) <= end) {
-    return new ScopeDesc(this, p->scope_decode_offset(),
-                         p->obj_decode_offset(), p->should_reexecute(), p->rethrow_exception(),
-                         p->return_oop());
+    return new ScopeDesc(this, p);
   }
   return NULL;
 }

src/hotspot/share/code/pcDesc.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2020, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -42,7 +42,9 @@ class PcDesc {
     PCDESC_reexecute               = 1 << 0,
     PCDESC_is_method_handle_invoke = 1 << 1,
     PCDESC_return_oop              = 1 << 2,
-    PCDESC_rethrow_exception       = 1 << 3
+    PCDESC_rethrow_exception       = 1 << 3,
+    PCDESC_has_ea_local_in_scope   = 1 << 4,
+    PCDESC_arg_escape              = 1 << 5
   };
 
   int _flags;
@@ -89,6 +91,16 @@ class PcDesc {
   bool     return_oop()                    const { return (_flags & PCDESC_return_oop) != 0;     }
   void set_return_oop(bool z)                    { set_flag(PCDESC_return_oop, z); }
 
+  // Indicates if there are objects in scope that, based on escape analysis, are local to the
+  // compiled method or local to the current thread, i.e. NoEscape or ArgEscape
+  bool     has_ea_local_in_scope()         const { return (_flags & PCDESC_has_ea_local_in_scope) != 0; }
+  void set_has_ea_local_in_scope(bool z)         { set_flag(PCDESC_has_ea_local_in_scope, z); }
+
+  // Indicates if this pc descriptor is at a call site where objects that do not escape the
+  // current thread are passed as arguments.
+  bool     arg_escape()                    const { return (_flags & PCDESC_arg_escape) != 0; }
+  void set_arg_escape(bool z)                    { set_flag(PCDESC_arg_escape, z); }
+
   // Returns the real pc
   address real_pc(const CompiledMethod* code) const;
 

src/hotspot/share/code/scopeDesc.cpp

@@ -31,23 +31,16 @@
 #include "oops/oop.inline.hpp"
 #include "runtime/handles.inline.hpp"
 
-ScopeDesc::ScopeDesc(const CompiledMethod* code, int decode_offset, int obj_decode_offset, bool reexecute, bool rethrow_exception, bool return_oop) {
+ScopeDesc::ScopeDesc(const CompiledMethod* code, PcDesc* pd, bool ignore_objects) {
+  int obj_decode_offset = ignore_objects ? DebugInformationRecorder::serialized_null : pd->obj_decode_offset();
   _code          = code;
-  _decode_offset = decode_offset;
+  _decode_offset = pd->scope_decode_offset();
   _objects       = decode_object_values(obj_decode_offset);
-  _reexecute     = reexecute;
-  _rethrow_exception = rethrow_exception;
-  _return_oop    = return_oop;
-  decode_body();
-}
-
-ScopeDesc::ScopeDesc(const CompiledMethod* code, int decode_offset, bool reexecute, bool rethrow_exception, bool return_oop) {
-  _code          = code;
-  _decode_offset = decode_offset;
-  _objects       = decode_object_values(DebugInformationRecorder::serialized_null);
-  _reexecute     = reexecute;
-  _rethrow_exception = rethrow_exception;
-  _return_oop    = return_oop;
+  _reexecute     = pd->should_reexecute();
+  _rethrow_exception = pd->rethrow_exception();
+  _return_oop    = pd->return_oop();
+  _has_ea_local_in_scope = ignore_objects ? false : pd->has_ea_local_in_scope();
+  _arg_escape    = ignore_objects ? false : pd->arg_escape();
   decode_body();
 }
 
@@ -59,6 +52,8 @@ void ScopeDesc::initialize(const ScopeDesc* parent, int decode_offset) {
   _reexecute     = false; //reexecute only applies to the first scope
   _rethrow_exception = false;
   _return_oop    = false;
+  _has_ea_local_in_scope = parent->has_ea_local_in_scope();
+  _arg_escape    = false;
   decode_body();
 }
 

src/hotspot/share/code/scopeDesc.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2020, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -60,12 +60,7 @@ class SimpleScopeDesc : public StackObj {
 class ScopeDesc : public ResourceObj {
  public:
   // Constructor
-  ScopeDesc(const CompiledMethod* code, int decode_offset, int obj_decode_offset, bool reexecute, bool rethrow_exception, bool return_oop);
-
-  // Calls above, giving default value of "serialized_null" to the
-  // "obj_decode_offset" argument.  (We don't use a default argument to
-  // avoid a .hpp-.hpp dependency.)
-  ScopeDesc(const CompiledMethod* code, int decode_offset, bool reexecute, bool rethrow_exception, bool return_oop);
+  ScopeDesc(const CompiledMethod* code, PcDesc* pd, bool ignore_objects = false);
 
   // Direct access to scope
   ScopeDesc* at_offset(int decode_offset) { return new ScopeDesc(this, decode_offset); }
@@ -76,6 +71,10 @@ class ScopeDesc : public ResourceObj {
   bool should_reexecute() const { return _reexecute; }
   bool rethrow_exception() const { return _rethrow_exception; }
   bool return_oop()       const { return _return_oop; }
+  // Returns true if one or more NoEscape or ArgEscape objects exist in
+  // any of the scopes at compiled pc.
+  bool has_ea_local_in_scope() const { return _has_ea_local_in_scope; }
+  bool arg_escape()       const { return _arg_escape; }
 
   GrowableArray<ScopeValue*>*   locals();
   GrowableArray<ScopeValue*>*   expressions();
@@ -105,6 +104,9 @@ class ScopeDesc : public ResourceObj {
   bool          _reexecute;
   bool          _rethrow_exception;
   bool          _return_oop;
+  bool          _has_ea_local_in_scope;       // One or more NoEscape or ArgEscape objects exist in
+                                              // any of the scopes at compiled pc.
+  bool          _arg_escape;                  // Compiled Java call in youngest scope passes ArgEscape
 
   // Decoding offsets
   int _decode_offset;