8335536: Fix assertion failure in IdealGraphPrinter when append is true

Reviewed-by: phh
Backport-of: 6db4c6a772df856fc3099c32a5b2c102a30d360c

src/hotspot/share/opto/idealGraphPrinter.cpp

@@ -141,21 +141,24 @@ void IdealGraphPrinter::init(const char* file_name, bool use_multiple_files, boo
   _depth = 0;
   _current_method = nullptr;
   _network_stream = nullptr;
+  _append = append;
 
   if (file_name != nullptr) {
-    init_file_stream(file_name, use_multiple_files, append);
+    init_file_stream(file_name, use_multiple_files);
   } else {
     init_network_stream();
   }
   _xml = new (ResourceObj::C_HEAP, mtCompiler) xmlStream(_output);
-  if (!append) {
+  if (!_append) {
     head(TOP_ELEMENT);
   }
 }
 
 // Destructor, close file or network stream
 IdealGraphPrinter::~IdealGraphPrinter() {
+  if (!_append) {
     tail(TOP_ELEMENT);
+  }
 
   // tty->print_cr("Walk time: %d", (int)_walk_time.milliseconds());
   // tty->print_cr("Output time: %d", (int)_output_time.milliseconds());
@@ -729,10 +732,10 @@ void IdealGraphPrinter::print(const char *name, Node *node) {
   _xml->flush();
 }
 
-void IdealGraphPrinter::init_file_stream(const char* file_name, bool use_multiple_files, bool append) {
+void IdealGraphPrinter::init_file_stream(const char* file_name, bool use_multiple_files) {
   ThreadCritical tc;
   if (use_multiple_files && _file_count != 0) {
-    assert(!append, "append should only be used for debugging with a single file");
+    assert(!_append, "append should only be used for debugging with a single file");
     ResourceMark rm;
     stringStream st;
     const char* dot = strrchr(file_name, '.');
@@ -744,10 +747,10 @@ void IdealGraphPrinter::init_file_stream(const char* file_name, bool use_multipl
     }
     _output = new (ResourceObj::C_HEAP, mtCompiler) fileStream(st.as_string(), "w");
   } else {
-    _output = new (ResourceObj::C_HEAP, mtCompiler) fileStream(file_name, append ? "a" : "w");
+    _output = new (ResourceObj::C_HEAP, mtCompiler) fileStream(file_name, _append ? "a" : "w");
   }
   if (use_multiple_files) {
-    assert(!append, "append should only be used for debugging with a single file");
+    assert(!_append, "append should only be used for debugging with a single file");
     _file_count++;
   }
 }
@@ -778,11 +781,18 @@ void IdealGraphPrinter::update_compiled_method(ciMethod* current_method) {
   assert(C != nullptr, "must already be set");
   if (current_method != _current_method) {
     // If a different method, end the old and begin with the new one.
+    if (_append) {
+      // Do not call `end_method` if we are appending, just update `_current_method`,
+      // because `begin_method` is not called in the constructor in append mode.
+      _current_method = current_method;
+    } else {
+      // End the old method and begin a new one.
+      // Don't worry about `_current_method`, `end_method` will clear it.
       end_method();
-    _current_method = nullptr;
       begin_method();
     }
   }
+}
 
 extern const char *NodeClassNames[];
 

src/hotspot/share/opto/idealGraphPrinter.hpp

@@ -93,6 +93,7 @@ class IdealGraphPrinter : public CHeapObj<mtCompiler> {
   bool _traverse_outs;
   Compile *C;
   double _max_freq;
+  bool _append;
 
   void print_method(ciMethod *method, int bci, InlineTree *tree);
   void print_inline_tree(InlineTree *tree);
@@ -110,7 +111,7 @@ class IdealGraphPrinter : public CHeapObj<mtCompiler> {
   void head(const char *name);
   void text(const char *s);
   void init(const char* file_name, bool use_multiple_files, bool append);
-  void init_file_stream(const char* file_name, bool use_multiple_files, bool append);
+  void init_file_stream(const char* file_name, bool use_multiple_files);
   void init_network_stream();
   IdealGraphPrinter();
   ~IdealGraphPrinter();