Fix HHBBC start-up to allow for const folding in distributed mode

Summary:
HHVM startup is a bit of a mess. You have to call a bunch of
functions in exactly the right order or things will break. This dance
was not done properly in process_init(), meaning the runtime was not
properly initialized. As a result, all attempts to const-fold (by
calling builtins) silently failed (the stack was not set up properly
so everything failed with a stack overflow). This required calling
hphp_request_init().

However, this caused a different problem. It turns out, due to quirks
of how RDS is initialized, that you can never call into the
interpreter/JIT from the process initial thread, no matter how you
initialize the runtime. This isn't a problem in general since we do
all the work on other threads. For distributed HHBBC though, the
thread doing the analysis is the initial thread.

Untangling this provided difficult. I fixed it for distributed HHBBC
by pre-initializing RDS before anything else, then providing a flag to
hphp_process_init() to tell it *not* to re-initialize RDS.

Reviewed By: mdko

Differential Revision: D89994296

fbshipit-source-id: 94da25d06ac217c2883554f1e58254056569e0ff

Author: ricklavoie

hphp/hhbbc/eval-cell.h

@@ -39,8 +39,8 @@ namespace HPHP::HHBBC {
  * will return non-static objects, or throw exceptions (e.g. tvAdd()
  * with an array and an int).
  *
- * This routine converts these things back to types.  In the case of
- * an exception it returns TInitCell.
+ * This routine converts these things back to types. In the case of
+ * an exception it returns std::nullopt.
  */
 template<class Pred>
 Optional<Type> eval_cell(Pred p) {

hphp/hhbbc/interp-builtin.cpp

@@ -729,10 +729,10 @@ bool optimize_builtin(ISS& env, const php::Func* func, const FCallArgs& fca) {
 }
 
 Optional<Type> const_fold(ISS& env,
-                                 uint32_t nArgs,
-                                 uint32_t numExtraInputs,
-                                 const php::Func& phpFunc,
-                                 bool variadicsPacked) {
+                          uint32_t nArgs,
+                          uint32_t numExtraInputs,
+                          const php::Func& phpFunc,
+                          bool variadicsPacked) {
   assertx(phpFunc.attrs & AttrIsFoldable);
 
   std::vector<TypedValue> args(nArgs);
@@ -771,7 +771,7 @@ Optional<Type> const_fold(ISS& env,
     );
   }
 
-  FTRACE(1, "invoking: {}\n", func->fullName()->data());
+  ITRACE(2, "invoking: {}\n", func->fullName());
 
   assertx(!Cfg::Jit::Enabled);
   // NB: Coeffects are already checked prior to here by `shouldAttemptToFold`

hphp/hhbbc/main.cpp

@@ -249,7 +249,7 @@ struct LoadRepoJob {
     process_init(config.o, config.gd, false);
   }
   static std::vector<W::Key> fini() {
-    process_exit();
+    process_exit(false);
     return std::move(s_keys);
   }
   static Variadic<W::Value> run(UnitEmitterSerdeWrapper wrapper) {
@@ -537,7 +537,6 @@ void compile_repo() {
     };
   };
 
-  HphpSession session{Treadmill::SessionKind::HHBBC};
   whole_program(
     std::move(inputs),
     std::move(config),
@@ -572,6 +571,7 @@ void process_init(const Options& o,
     setrlimit(RLIMIT_CORE, &rl);
   }
 
+  rds::threadInit();
   rds::local::init();
   SCOPE_FAIL { rds::local::fini(); };
 
@@ -608,7 +608,7 @@ void process_init(const Options& o,
   gd.load(false);
 
   register_process_init();
-  hphp_process_init(!fullInit);
+  hphp_process_init(!fullInit, true);
   SCOPE_FAIL { hphp_process_exit(); };
 
   options = o;
@@ -624,9 +624,15 @@ void process_init(const Options& o,
   Cfg::LoadFromGlobalDataOnlyHHBBC(gd);
 
   options.SourceRootForFileBC = gd.SourceRootForFileBC;
+
+  if (fullInit) hphp_session_init(Treadmill::SessionKind::HHBBC);
 }
 
-void process_exit() {
+void process_exit(bool full) {
+  if (full) {
+    hphp_context_exit();
+    hphp_session_exit();
+  }
   hphp_process_exit();
   rds::local::fini();
 }
@@ -653,7 +659,7 @@ int main(int argc, char** argv) try {
   gd.load(false);
 
   process_init(options, gd, true);
-  SCOPE_EXIT { process_exit(); };
+  SCOPE_EXIT { process_exit(true); };
 
   Logger::LogLevel = logging ? Logger::LogInfo : Logger::LogError;
   Logger::Escape = false;

hphp/hhbbc/misc.h

@@ -325,7 +325,7 @@ using UniquePtrRefVec = std::vector<UniquePtrRef<T>>;
 // structures will be parsed and initialized.
 void process_init(const Options&, const RepoGlobalData&, bool full);
 // Undo process_init().
-void process_exit();
+void process_exit(bool full);
 
 }}
 

hphp/runtime/base/program-functions.cpp

@@ -2547,12 +2547,13 @@ static void update_constants_and_options() {
   }
 }
 
-void hphp_thread_init(bool skipExtensions /* = false */) {
+void hphp_thread_init(bool skipExtensions /* = false */,
+                      bool skipRDSInit /* = false */) {
   init_current_pthread_stack_limits();
 #if USE_JEMALLOC
   arenas_thread_init();
 #endif
-  rds::threadInit();
+  if (!skipRDSInit) rds::threadInit();
   ServerStats::GetLogger();
   zend_get_bigint_data();
   zend_rand_init();
@@ -2646,7 +2647,8 @@ void init_current_pthread_stack_limits() {
   }
 }
 
-void hphp_process_init(bool initForWorkerProcess /* = false */) {
+void hphp_process_init(bool initForWorkerProcess /* = false */,
+                       bool skipRDSInit /* = false */) {
   init_current_pthread_stack_limits();
   BootStats::mark("pthread_init");
 
@@ -2659,9 +2661,9 @@ void hphp_process_init(bool initForWorkerProcess /* = false */) {
   timezone_init();
   BootStats::mark("timezone_init");
 
-  rds::processInit();
+  if (!skipRDSInit) rds::processInit();
 
-  hphp_thread_init(/* skipExtensions= */ initForWorkerProcess);
+  hphp_thread_init(/* skipExtensions= */ initForWorkerProcess, skipRDSInit);
 
   struct sigaction action = {};
   action.sa_sigaction = on_timeout;

hphp/runtime/base/program-functions.h

@@ -87,7 +87,8 @@ struct ExecutionContext;
  * If `initAsWorker` is set, JIT data structure and extensions will not be
  * initialized as they're expensive to set up and unused by workers.
  */
-void hphp_process_init(bool initForWorkerProcess = false);
+void hphp_process_init(bool initForWorkerProcess = false,
+                       bool skipRDSInit = false);
 void cli_client_init();
 void cli_client_thread_init();
 void cli_client_thread_exit();
@@ -117,7 +118,8 @@ bool hphp_invoke(ExecutionContext *context,
                  bool allowDynCallNoPointer = false);
 void hphp_context_exit();
 
-void hphp_thread_init(bool skipExtensions = false);
+void hphp_thread_init(bool skipExtensions = false,
+                      bool skipRDSInit = false);
 void hphp_thread_exit(bool skipExtensions = false);
 
 void init_current_pthread_stack_limits();