Fix running synth benchmarks directly via synth.cpp

Summary:
There was a mistake in a previous change that was silencing some of
the options getting passed to the benchmark runner. Specifically,
the option to print the GC stats was missing, which is critical since that
is what prints out performance numbers.

Reviewed By: avp

Differential Revision: D22464903

fbshipit-source-id: bc4f7aed8cb4f3cc6284bdcbe2c2c9fd4bb468b0

tools/synth/synth.cpp

@@ -221,31 +221,6 @@ int main(int argc, char **argv) {
       llvh::EnableStatistics();
 #endif
 
-    std::vector<std::string> bytecodeFiles{cl::BytecodeFiles.begin(),
-                                           cl::BytecodeFiles.end()};
-    if (!cl::Trace.empty()) {
-      // If this is tracing mode, get the trace instead of the stats.
-      shouldPrintGCStats = false;
-      options.shouldTrackIO = false;
-      std::error_code ec;
-      auto os = ::hermes::make_unique<llvh::raw_fd_ostream>(
-          cl::Trace.c_str(),
-          ec,
-          llvh::sys::fs::CD_CreateAlways,
-          llvh::sys::fs::FA_Write,
-          llvh::sys::fs::OF_Text);
-      if (ec) {
-        throw std::system_error(ec);
-      }
-      TraceInterpreter::execAndTrace(
-          cl::TraceFile, bytecodeFiles, options, std::move(os));
-      llvh::outs() << "\nWrote output trace to: " << cl::Trace << "\n";
-    } else {
-      llvh::outs() << TraceInterpreter::execAndGetStats(
-                          cl::TraceFile, bytecodeFiles, options)
-                   << "\n";
-    }
-
     options.gcConfigBuilder.withShouldRecordStats(shouldPrintGCStats);
     if (minHeapSize) {
       options.gcConfigBuilder.withMinHeapSize(*minHeapSize);
@@ -279,6 +254,31 @@ int main(int argc, char **argv) {
       options.gcConfigBuilder.withSanitizeConfig(sanitizeConfigBuilder.build());
     }
 
+    std::vector<std::string> bytecodeFiles{cl::BytecodeFiles.begin(),
+                                           cl::BytecodeFiles.end()};
+    if (!cl::Trace.empty()) {
+      // If this is tracing mode, get the trace instead of the stats.
+      options.gcConfigBuilder.withShouldRecordStats(false);
+      options.shouldTrackIO = false;
+      std::error_code ec;
+      auto os = ::hermes::make_unique<llvh::raw_fd_ostream>(
+          cl::Trace.c_str(),
+          ec,
+          llvh::sys::fs::CD_CreateAlways,
+          llvh::sys::fs::FA_Write,
+          llvh::sys::fs::OF_Text);
+      if (ec) {
+        throw std::system_error(ec);
+      }
+      TraceInterpreter::execAndTrace(
+          cl::TraceFile, bytecodeFiles, options, std::move(os));
+      llvh::outs() << "\nWrote output trace to: " << cl::Trace << "\n";
+    } else {
+      llvh::outs() << TraceInterpreter::execAndGetStats(
+                          cl::TraceFile, bytecodeFiles, options)
+                   << "\n";
+    }
+
 #if !defined(NDEBUG) || defined(LLVM_ENABLE_STATS)
     if (cl::PrintStats)
       llvh::PrintStatistics(llvh::outs());