bench: Fix initialization order in registration

random-zebra · random-zebra · commit e94cf15919a8 · 2020-05-28T02:13:16.000+02:00
- backports bitcoin/bitcoin@29c5328 The initialization order of global data structures in different implementation units is undefined. Making use of this is essentially gambling on what the linker does, the so-called [Static initialization order fiasco](https://isocpp.org/wiki/faq/ctors#static-init-order). In this case it apparently worked on Linux but failed on OpenBSD and FreeBSD. To create it on first use, make the registration structure local to a function. Fixes bitcoin#8910.
diff --git a/src/bench/bench.cpp b/src/bench/bench.cpp
@@ -10,7 +10,10 @@
 #include <iostream>
 #include <sys/time.h>
 
-std::map<std::string, benchmark::BenchFunction> benchmark::BenchRunner::benchmarks;
+benchmark::BenchRunner::BenchmarkMap &benchmark::BenchRunner::benchmarks() {
+    static std::map<std::string, benchmark::BenchFunction> benchmarks_map;
+    return benchmarks_map;
+}
 
 static double gettimedouble(void) {
     struct timeval tv;
@@ -20,7 +23,7 @@ static double gettimedouble(void) {
 
 benchmark::BenchRunner::BenchRunner(std::string name, benchmark::BenchFunction func)
 {
-    benchmarks.insert(std::make_pair(name, func));
+    benchmarks().insert(std::make_pair(name, func));
 }
 
 void
@@ -30,12 +33,9 @@ benchmark::BenchRunner::RunAll(double elapsedTimeForOne)
     std::cout << "#Benchmark" << "," << "count" << "," << "min" << "," << "max" << "," << "average" << ","
               << "min_cycles" << "," << "max_cycles" << "," << "average_cycles" << "\n";
 
-    for (std::map<std::string,BenchFunction>::iterator it = benchmarks.begin();
-         it != benchmarks.end(); ++it) {
-
-        State state(it->first, elapsedTimeForOne);
-        BenchFunction& func = it->second;
-        func(state);
+    for (const auto &p: benchmarks()) {
+        State state(p.first, elapsedTimeForOne);
+        p.second(state);
     }
     perf_fini();
 }
diff --git a/src/bench/bench.h b/src/bench/bench.h
@@ -61,7 +61,8 @@ namespace benchmark {
 
     class BenchRunner
     {
-        static std::map<std::string, BenchFunction> benchmarks;
+        typedef std::map<std::string, BenchFunction> BenchmarkMap;
+        static BenchmarkMap &benchmarks();
 
     public:
         BenchRunner(std::string name, BenchFunction func);

Original file line number	Diff line number	Diff line change
`@@ -61,7 +61,8 @@ namespace benchmark {`
`61`	`61`
`62`	`62`	`class BenchRunner`
`63`	`63`	`{`
`64`		`- static std::map<std::string, BenchFunction> benchmarks;`
	`64`	`+ typedef std::map<std::string, BenchFunction> BenchmarkMap;`
	`65`	`+ static BenchmarkMap &benchmarks();`
`65`	`66`
`66`	`67`	`public:`
`67`	`68`	`BenchRunner(std::string name, BenchFunction func);`