From 299b0f5b396a0574819e8d48b3b3f232786e07b8 Mon Sep 17 00:00:00 2001
From: Arnab De <arnabde@fb.com>
Date: Tue, 22 Jun 2021 15:55:30 -0700
Subject: [PATCH] More builtin optimizations for lazy classes

Summary: Optimize `type_structure` and `is_a` for lazy classes.

Reviewed By: paulbiss

Differential Revision: D27976309

fbshipit-source-id: ebb02625dca5ce7ad25deb7fa35b2e4277ce0256
---
 hphp/runtime/vm/jit/irgen-builtin.cpp | 19 +++++++++++++++----
 hphp/runtime/vm/jit/simplify.cpp      |  8 +++++++-
 2 files changed, 22 insertions(+), 5 deletions(-)

diff --git a/hphp/runtime/vm/jit/irgen-builtin.cpp b/hphp/runtime/vm/jit/irgen-builtin.cpp
index 350dbc9473f..8bd14011399 100644
--- a/hphp/runtime/vm/jit/irgen-builtin.cpp
+++ b/hphp/runtime/vm/jit/irgen-builtin.cpp
@@ -125,13 +125,22 @@ SSATmp* is_a_impl(IRGS& env, const ParamPrep& params, bool subclassOnly) {
   auto const allowClass = nparams == 3 ? params[2].value : cns(env, false);
 
   if (!obj->type().subtypeOfAny(TCls, TObj) ||
-      !cls->type().subtypeOfAny(TCls, TStr) ||
+      !cls->type().subtypeOfAny(TCls, TLazyCls, TStr) ||
       !allowClass->isA(TBool)) {
     return nullptr;
   }
 
   auto const lhs = obj->isA(TObj) ? gen(env, LdObjClass, obj) : obj;
-  auto const rhs = cls->isA(TStr) ? gen(env, LookupClsRDS, cls) : cls;
+  auto const rhs = [&] {
+    if (cls->isA(TStr)) {
+      return gen(env, LookupClsRDS, cls);
+    }
+    if (cls->isA(TLazyCls)) {
+      auto const cname = gen(env, LdLazyClsName, cls);
+      return gen(env, LookupClsRDS, cname);
+    }
+    return cls;
+  }();
 
   return cond(
     env,
@@ -526,12 +535,14 @@ SSATmp* impl_opt_type_structure(IRGS& env, const ParamPrep& params,
   auto const clsNameTmp = params[0].value;
   auto const cnsNameTmp = params[1].value;
 
-  if (!clsNameTmp->isA(TStr)) return nullptr;
+  if (!clsNameTmp->isA(TStr|TCls|TLazyCls)) return nullptr;
   if (!cnsNameTmp->hasConstVal(TStaticStr)) return nullptr;
   auto const cnsName = cnsNameTmp->strVal();
 
   auto const clsTmp = [&] () -> SSATmp* {
-    if (clsNameTmp->inst()->is(LdClsName)) {
+    if (clsNameTmp->isA(TCls)) return clsNameTmp;
+    if (clsNameTmp->inst()->is(LdClsName) ||
+        clsNameTmp->inst()->is(LdLazyCls)) {
       return clsNameTmp->inst()->src(0);
     }
     return ldCls(env, clsNameTmp, make_opt_catch(env, params));
diff --git a/hphp/runtime/vm/jit/simplify.cpp b/hphp/runtime/vm/jit/simplify.cpp
index f931403271a..068968ff8d3 100644
--- a/hphp/runtime/vm/jit/simplify.cpp
+++ b/hphp/runtime/vm/jit/simplify.cpp
@@ -412,9 +412,15 @@ SSATmp* simplifyLookupClsCtxCns(State& env, const IRInstruction* inst) {
 SSATmp* simplifyLdCls(State& env, const IRInstruction* inst) {
   auto const str = inst->src(0);
   auto const cls = inst->src(1);
-  if (str->inst()->is(LdClsName, LdLazyCls)) {
+  if (str->inst()->is(LdClsName)) {
     return str->inst()->src(0);
   }
+  if (str->inst()->is(LdLazyClsName)) {
+    auto const lcls = str->inst()->src(0);
+    if (lcls->inst()->is(LdLazyCls)) {
+      return lcls->inst()->src(0);
+    }
+  }
   if (str->hasConstVal() && (cls->hasConstVal(TCls) || cls->isA(TNullptr))) {
     auto const sval = str->strVal();
     auto const cval = cls->hasConstVal(TCls) ? cls->clsVal() : nullptr;
-- 
2.11.4.GIT