stacktrace: Change print_backtrace_symbol to get_backtrace_string

To make backtrace string could be printed selectively, Change each
function not to print inside the function rather return the report
string.

  print_backtrace_symbol            -> get_backtrace_string
  print_backtrace_symbol_flamegraph -> get_backtrace_string_flamegraph

Signed-off-by: Bojun Seo <[email protected]>

src/stacktrace.cc

@@ -13,6 +13,7 @@
 
 #include <algorithm>
 #include <fstream>
+#include <iomanip>
 #include <map>
 #include <sstream>
 #include <vector>
@@ -93,7 +94,7 @@ void release_backtrace(void *addr)
 	addrmap.erase(addrit);
 }
 
-static void print_backtrace_symbol(int count, void *addr)
+static void get_backtrace_string(int count, void *addr, std::stringstream &ss_bt)
 {
 	Dl_info dlip;
 	char *symbol;
@@ -102,15 +103,12 @@ static void print_backtrace_symbol(int count, void *addr)
 	int dl_ret;
 	int len = SYMBOL_MAXLEN;
 
-#if __SIZEOF_LONG__ == 4
-	pr_out("%2d [%#10lx] ", count, (unsigned long)addr);
-#else
-	pr_out("%2d [%#14lx] ", count, (unsigned long)addr);
-#endif
+	ss_bt << std::dec << count << " [0x" << std::hex <<
+		std::setw(4 + __SIZEOF_LONG__) << (unsigned long)addr << "] ";
 	// dladdr() translates address to symbolic info.
 	dl_ret = dladdr(addr, &dlip);
 	if (dl_ret == 0) {
-		pr_out("?\n");
+		ss_bt << "?\n";
 		return;
 	}
 
@@ -127,14 +125,15 @@ static void print_backtrace_symbol(int count, void *addr)
 		}
 		offset = static_cast<int>(static_cast<int *>(addr) -
 					  static_cast<int *>(dlip.dli_saddr));
-		pr_out("%s +%#x ", symbol, offset);
+		ss_bt << symbol << " +0x" << offset << " ";
 		free(symbol);
 	}
 	offset = (int)((char *)addr - (char *)(dlip.dli_fbase));
-	pr_out("(%s +%#x)\n", dlip.dli_fname, offset);
+	ss_bt << "(" << dlip.dli_fname << " +0x" << offset << ")\n";
 }
 
-static void print_backtrace_symbol_flamegraph(void *addr, const char *semicolon)
+static void get_backtrace_string_flamegraph(void *addr, const char *semicolon,
+					    std::stringstream &ss_bt)
 {
 	Dl_info dlip;
 	char *symbol;
@@ -160,11 +159,11 @@ static void print_backtrace_symbol_flamegraph(void *addr, const char *semicolon)
 		}
 		offset = static_cast<int>(static_cast<int *>(addr) -
 					  static_cast<int *>(dlip.dli_saddr));
-		pr_out("%s%s+%#x", semicolon, symbol, offset);
+		ss_bt << semicolon << symbol << "+0x" << offset;
 		free(symbol);
 	}
 	else {
-		pr_out("%s%s+%p", semicolon, dlip.dli_fname, addr);
+		ss_bt << semicolon << dlip.dli_fname << addr;
 	}
 }
 
@@ -305,16 +304,19 @@ static void print_dump_stackmap(std::vector<std::pair<stack_trace_t, stack_info_
 
 		const stack_trace_t &stack_trace = sorted_stack[i].first;
 		std::string age = get_delta_time_unit(current - info.birth_time);
-
-		pr_out("=== backtrace #%d === [count/peak: %zd/%zd] "
-		       "[size/peak: %s/%s] [age: %s]\n",
-		       ++cnt, info.count, info.peak_count, get_byte_unit(info.total_size).c_str(),
-		       get_byte_unit(info.peak_total_size).c_str(), age.c_str());
-
+		std::stringstream ss_intro;
+		std::stringstream ss_bt;
+
+		++cnt;
+		ss_intro << "=== backtrace #" << cnt << " === [count/peak: " << info.count << "/"
+			 << info.peak_count << "] "
+			 << "[size/peak: " << get_byte_unit(info.total_size) << "/"
+			 << get_byte_unit(info.peak_total_size) << "] [age: " << age << "]\n";
+		ss_bt << std::setfill('0');
 		for (int j = 0; j < info.stack_depth; j++)
-			print_backtrace_symbol(j, stack_trace[j]);
+			get_backtrace_string(j, stack_trace[j], ss_bt);
 
-		pr_out("\n");
+		pr_out("%s%s\n", ss_intro.str().c_str(), ss_bt.str().c_str());
 	}
 }
 
@@ -331,12 +333,15 @@ print_dump_stackmap_flamegraph(std::vector<std::pair<stack_trace_t, stack_info_t
 			break;
 
 		const stack_trace_t &stack_trace = sorted_stack[i].first;
+		std::stringstream ss_bt;
 
+		ss_bt << std::hex;
 		for (size_t j = 0; j < info.stack_depth; ++j) {
-			print_backtrace_symbol_flamegraph(stack_trace[info.stack_depth - 1 - j],
-							  semicolon);
+			get_backtrace_string_flamegraph(stack_trace[info.stack_depth - 1 - j],
+							semicolon, ss_bt);
 			semicolon = ";";
 		}
+		pr_out("%s", ss_bt.str().c_str());
 		pr_out(" %" PRIu64 "\n", size);
 	}