Merge pull request #1020 from goldshtn/duplicate_modules

cc: Don't parse the same module multiple times for USDT probes

src/cc/usdt.cc

@@ -200,7 +200,13 @@ void Context::_each_probe(const char *binpath, const struct bcc_elf_usdt *probe,
 }
 
 int Context::_each_module(const char *modpath, uint64_t, uint64_t, void *p) {
-  bcc_elf_foreach_usdt(modpath, _each_probe, p);
+  Context *ctx = static_cast<Context *>(p);
+  // Modules may be reported multiple times if they contain more than one
+  // executable region. We are going to parse the ELF on disk anyway, so we
+  // don't need these duplicates.
+  if (ctx->modules_.insert(modpath).second /*inserted new?*/) {
+    bcc_elf_foreach_usdt(modpath, _each_probe, p);
+  }
   return 0;
 }
 

src/cc/usdt.h

@@ -191,6 +191,7 @@ public:
 
 class Context {
   std::vector<std::unique_ptr<Probe>> probes_;
+  std::unordered_set<std::string> modules_;
 
   optional<int> pid_;
   optional<ProcStat> pid_stat_;