8255245: C1: Fix output of -XX:+PrintCFGToFile to open it with visualizer

Reviewed-by: kvn, xliu

src/hotspot/share/c1/c1_CFGPrinter.cpp

@@ -325,7 +325,7 @@ void CFGPrinterOutput::print_intervals(IntervalList* intervals, const char* name
 
   for (int i = 0; i < intervals->length(); i++) {
     if (intervals->at(i) != NULL) {
-      intervals->at(i)->print_on(output());
+      intervals->at(i)->print_on(output(), true);
     }
   }
 

src/hotspot/share/c1/c1_LinearScan.cpp

@@ -3212,6 +3212,12 @@ void LinearScan::print_reg_num(outputStream* out, int reg_num) {
     return;
   }
 
+  LIR_Opr opr = get_operand(reg_num);
+  assert(opr->is_valid(), "unknown register");
+  opr->print(out);
+}
+
+LIR_Opr LinearScan::get_operand(int reg_num) {
   LIR_Opr opr = LIR_OprFact::illegal();
 
 #ifdef X86
@@ -3231,9 +3237,9 @@ void LinearScan::print_reg_num(outputStream* out, int reg_num) {
     opr = LIR_OprFact::single_xmm(reg_num - pd_first_xmm_reg);
 #endif
   } else {
-    assert(false, "unknown register");
+    // reg_num == -1 or a virtual register, return the illegal operand
   }
-  opr->print(out);
+  return opr;
 }
 
 Interval* LinearScan::find_interval_at(int reg_num) const {
@@ -4598,7 +4604,7 @@ bool Interval::intersects_any_children_of(Interval* interval) const {
 
 
 #ifndef PRODUCT
-void Interval::print_on(outputStream* out) const {
+void Interval::print_on(outputStream* out, bool is_cfg_printer) const {
   const char* SpillState2Name[] = { "no definition", "no spill store", "one spill store", "store at definition", "start in memory", "no optimization" };
   const char* UseKind2Name[] = { "N", "L", "S", "M" };
 
@@ -4608,18 +4614,29 @@ void Interval::print_on(outputStream* out) const {
   } else {
     type_name = type2name(type());
   }
-
   out->print("%d %s ", reg_num(), type_name);
-  if (reg_num() < LIR_OprDesc::vreg_base) {
-    LinearScan::print_reg_num(out, assigned_reg());
-  } else if (assigned_reg() != -1 && (LinearScan::num_physical_regs(type()) == 1 || assigned_regHi() != -1)) {
-    LinearScan::calc_operand_for_interval(this)->print(out);
-  } else {
-    // Virtual register that has no assigned register yet.
-    out->print("[ANY]");
-  }
 
-  out->print(" %d %d ", split_parent()->reg_num(), (register_hint(false) != NULL ? register_hint(false)->reg_num() : -1));
+  if (is_cfg_printer) {
+    // Special version for compatibility with C1 Visualizer.
+    LIR_Opr opr = LinearScan::get_operand(reg_num());
+    if (opr->is_valid()) {
+      out->print("\"");
+      opr->print(out);
+      out->print("\" ");
+    }
+  } else {
+    // Improved output for normal debugging.
+    if (reg_num() < LIR_OprDesc::vreg_base) {
+      LinearScan::print_reg_num(out, assigned_reg());
+    } else if (assigned_reg() != -1 && (LinearScan::num_physical_regs(type()) == 1 || assigned_regHi() != -1)) {
+      LinearScan::calc_operand_for_interval(this)->print(out);
+    } else {
+      // Virtual register that has no assigned register yet.
+      out->print("[ANY]");
+    }
+    out->print(" ");
+  }
+  out->print("%d %d ", split_parent()->reg_num(), (register_hint(false) != NULL ? register_hint(false)->reg_num() : -1));
 
   // print ranges
   Range* cur = _first;

src/hotspot/share/c1/c1_LinearScan.hpp

@@ -369,6 +369,7 @@ class LinearScan : public CompilationResourceObj {
   void        print_lir(int level, const char* label, bool hir_valid = true);
   static void print_reg_num(int reg_num) { print_reg_num(tty, reg_num); }
   static void print_reg_num(outputStream* out, int reg_num);
+  static LIR_Opr get_operand(int reg_num);
 #endif
 
 #ifdef ASSERT
@@ -633,7 +634,11 @@ class Interval : public CompilationResourceObj {
   // printing
 #ifndef PRODUCT
   void print() const { print_on(tty); }
-  void print_on(outputStream* out) const;
+  void print_on(outputStream* out) const {
+    print_on(out, false);
+  }
+  // Special version for compatibility with C1 Visualizer.
+  void print_on(outputStream* out, bool is_cfg_printer) const;
 
   // Used for debugging
   void print_parent() const;