Don't do branch profiling for profiling translations

Reviewed By: markw65

Differential Revision: D4435131

fbshipit-source-id: 0eff93f31119627615ecdbe7955fa5c2bfaeba4b

hphp/runtime/vm/jit/types.h

@@ -104,6 +104,24 @@ inline std::string show(TransKind k) {
   not_reached();
 }
 
+inline bool isProfiling(TransKind k) {
+  switch (k) {
+    case TransKind::Profile:
+    case TransKind::ProfPrologue:
+      return true;
+
+    case TransKind::Anchor:
+    case TransKind::Interp:
+    case TransKind::Live:
+    case TransKind::LivePrologue:
+    case TransKind::Optimize:
+    case TransKind::OptPrologue:
+    case TransKind::Invalid:
+      return false;
+  }
+  always_assert(false);
+}
+
 inline bool isPrologue(TransKind k) {
   switch (k) {
     case TransKind::LivePrologue:

hphp/runtime/vm/jit/vasm-x64.cpp

@@ -1043,11 +1043,12 @@ void optimizeX64(Vunit& unit, const Abi& abi, bool regalloc) {
 
   assertx(checkWidths(unit));
 
-  if (abi.canSpill && RuntimeOption::EvalProfBranchSampleFreq > 0) {
-    // Only profile branches if we're allowed to spill (and if branch profiling
-    // is on, of course).  This is not only for the freedom to generate
-    // arbitrary code, but also because we don't want to profile unique stubs
-    // and such.
+  if (unit.context && isProfiling(unit.context->kind) && abi.canSpill &&
+      RuntimeOption::EvalProfBranchSampleFreq > 0) {
+    // Even when branch profiling is on, we still only want to profile
+    // non-profiling translations of PHP functions.  We also require that we
+    // can spill, so that we can generate arbitrary profiling code, and also to
+    // ensure we don't profile unique stubs and such.
     profile_branches(unit);
   }