--- old/src/hotspot/share/gc/g1/g1GCPhaseTimes.cpp	2019-12-13 10:43:20.764639700 +0900
+++ new/src/hotspot/share/gc/g1/g1GCPhaseTimes.cpp	2019-12-13 10:43:20.094516400 +0900
@@ -37,7 +37,13 @@
 #include "runtime/os.hpp"
 #include "utilities/macros.hpp"
 
-static const char* Indents[5] = {"", "  ", "    ", "      ", "        "};
+static void generate_indent(int num_indent, char* buf, size_t buflen){
+  if (num_indent <= 0) {
+    *buf = '\0';
+  } else {
+    jio_snprintf(buf, buflen, "%*c", num_indent * 2, ' ');
+  }
+}
 
 G1GCPhaseTimes::G1GCPhaseTimes(STWGCTimer* gc_timer, uint max_gc_threads) :
   _max_gc_threads(max_gc_threads),
@@ -309,16 +315,19 @@
 }
 
 void G1GCPhaseTimes::log_phase(WorkerDataArray<double>* phase, uint indent, outputStream* out, bool print_sum) const {
-  out->print("%s", Indents[indent]);
+  char buf[O_BUFLEN];
+  generate_indent(indent, buf, O_BUFLEN);
+  out->print("%s", buf);
   phase->print_summary_on(out, print_sum);
-  details(phase, Indents[indent]);
+  details(phase, buf);
 
   for (uint i = 0; i < phase->MaxThreadWorkItems; i++) {
     WorkerDataArray<size_t>* work_items = phase->thread_work_items(i);
     if (work_items != NULL) {
-      out->print("%s", Indents[indent + 1]);
+      generate_indent(indent + 1, buf, O_BUFLEN);
+      out->print("%s", buf);
       work_items->print_summary_on(out, true);
-      details(work_items, Indents[indent + 1]);
+      details(work_items, buf);
     }
   }
 }
@@ -343,32 +352,43 @@
 #define TIME_FORMAT "%.1lfms"
 
 void G1GCPhaseTimes::info_time(const char* name, double value) const {
-  log_info(gc, phases)("%s%s: " TIME_FORMAT, Indents[1], name, value);
+  char buf[O_BUFLEN];
+  generate_indent(1, buf, O_BUFLEN);
+  log_info(gc, phases)("%s%s: " TIME_FORMAT, buf, name, value);
 }
 
 void G1GCPhaseTimes::debug_time(const char* name, double value) const {
-  log_debug(gc, phases)("%s%s: " TIME_FORMAT, Indents[2], name, value);
+  char buf[O_BUFLEN];
+  generate_indent(2, buf, O_BUFLEN);
+  log_debug(gc, phases)("%s%s: " TIME_FORMAT, buf, name, value);
 }
 
 void G1GCPhaseTimes::debug_time_for_reference(const char* name, double value) const {
+  char buf[O_BUFLEN];
+  generate_indent(2, buf, O_BUFLEN);
+
   LogTarget(Debug, gc, phases) lt;
   LogTarget(Debug, gc, phases, ref) lt2;
 
   if (lt.is_enabled()) {
     LogStream ls(lt);
-    ls.print_cr("%s%s: " TIME_FORMAT, Indents[2], name, value);
+    ls.print_cr("%s%s: " TIME_FORMAT, buf, name, value);
   } else if (lt2.is_enabled()) {
     LogStream ls(lt2);
-    ls.print_cr("%s%s: " TIME_FORMAT, Indents[2], name, value);
+    ls.print_cr("%s%s: " TIME_FORMAT, buf, name, value);
   }
 }
 
 void G1GCPhaseTimes::trace_time(const char* name, double value) const {
-  log_trace(gc, phases)("%s%s: " TIME_FORMAT, Indents[3], name, value);
+  char buf[O_BUFLEN];
+  generate_indent(3, buf, O_BUFLEN);
+  log_trace(gc, phases)("%s%s: " TIME_FORMAT, buf, name, value);
 }
 
 void G1GCPhaseTimes::trace_count(const char* name, size_t value) const {
-  log_trace(gc, phases)("%s%s: " SIZE_FORMAT, Indents[3], name, value);
+  char buf[O_BUFLEN];
+  generate_indent(3, buf, O_BUFLEN);
+  log_trace(gc, phases)("%s%s: " SIZE_FORMAT, buf, name, value);
 }
 
 double G1GCPhaseTimes::print_pre_evacuate_collection_set() const {