HHBBC does not run in lowptr mode so no need to use LSString

Summary:
- LowPtr is going to be replaced with PackedPtr
- This code can just use const StringData* because HHBBC runs in non-lowptr mode anyway.

Reviewed By: ricklavoie

Differential Revision: D77181337

fbshipit-source-id: a1b0afdb9b92f20d2ed47bf73fbf4b0648b21510

Author: WizKid

hphp/hhbbc/bc.h

@@ -164,7 +164,7 @@ struct FCallArgsLong : FCallArgsBase {
   explicit FCallArgsLong(Flags flags, uint32_t numArgs, uint32_t numRets,
                          std::unique_ptr<uint8_t[]> inoutArgs,
                          std::unique_ptr<uint8_t[]> readonlyArgs,
-                         BlockId asyncEagerTarget, LSString context)
+                         BlockId asyncEagerTarget, SString context)
     : FCallArgsBase(flags, numArgs, numRets)
     , inoutArgs(std::move(inoutArgs))
     , readonlyArgs(std::move(readonlyArgs))
@@ -173,7 +173,7 @@ struct FCallArgsLong : FCallArgsBase {
   explicit FCallArgsLong(FCallArgsBase base,
                          std::unique_ptr<uint8_t[]> inoutArgs,
                          std::unique_ptr<uint8_t[]> readonlyArgs,
-                         BlockId asyncEagerTarget, LSString context)
+                         BlockId asyncEagerTarget, SString context)
     : FCallArgsBase(std::move(base))
     , inoutArgs(std::move(inoutArgs))
     , readonlyArgs(std::move(readonlyArgs))
@@ -321,15 +321,15 @@ struct FCallArgsLong : FCallArgsBase {
   std::unique_ptr<uint8_t[]> inoutArgs;
   std::unique_ptr<uint8_t[]> readonlyArgs;
   BlockId asyncEagerTarget;
-  LSString context;
+  SString context;
 
   template <typename SerDe>
   static copy_ptr<FCallArgsLong> makeForSerde(SerDe& sd) {
     static_assert(SerDe::deserializing);
 
     auto base = sd.template make<FCallArgsBase>();
     BlockId asyncEagerTarget;
-    LSString context;
+    SString context;
     sd(asyncEagerTarget)(context);
 
     bool hasInout;
@@ -385,7 +385,7 @@ struct FCallArgs {
             std::unique_ptr<uint8_t[]> inoutArgs,
             std::unique_ptr<uint8_t[]> readonlyArgs,
             BlockId asyncEagerTarget,
-            LSString context)
+            SString context)
     : l{flags, numArgs, numRets,
         std::move(inoutArgs), std::move(readonlyArgs),
         asyncEagerTarget, context} {}
@@ -515,7 +515,7 @@ struct FCallArgs {
   Flavor popFlavor(uint32_t i) const {
     return l->template popFlavor<nin,nobj>(i);
   }
-  LSString context() const { return l->context; }
+  SString context() const { return l->context; }
 
   template <typename SerDe> static FCallArgs makeForSerde(SerDe& sd) {
     static_assert(SerDe::deserializing);
@@ -540,7 +540,7 @@ using SwitchTab     = CompactVector<BlockId>;
 
 // The final entry in the SSwitchTab is the default case, it will
 // always have a nullptr for the string.
-using SSwitchTabEnt = std::pair<LSString,BlockId>;
+using SSwitchTabEnt = std::pair<SString,BlockId>;
 using SSwitchTab    = CompactVector<SSwitchTabEnt>;
 
 //////////////////////////////////////////////////////////////////////

hphp/hhbbc/wide-func.cpp

@@ -36,8 +36,6 @@ TRACE_SET_MOD(hhbbc_mem)
 
 using Buffer = CompressedBytecode;
 
-static_assert(std::is_same<LSString, LowStringPtr>::value);
-
 constexpr int32_t kNoSrcLoc = -1;
 
 constexpr uint8_t k16BitCode = 0xfe;
@@ -103,7 +101,7 @@ T decode(const Buffer& buffer, size_t& pos) {
   if constexpr (std::is_same<T, FCallArgs>::value) {
     using FCA = FCallArgsBase;
     auto const base     = decode<FCA>(buffer, pos);
-    auto const context  = decode<LSString>(buffer, pos);
+    auto const context  = decode<SString>(buffer, pos);
     auto const aeTarget = decode<BlockId>(buffer, pos) + NoBlockId;
     auto inout = std::unique_ptr<uint8_t[]>();
     if (base.flags & FCallArgsFlags::EnforceInOut) {
@@ -136,14 +134,14 @@ T decode(const Buffer& buffer, size_t& pos) {
     return T{first, count};
   }
 
-  if constexpr (std::is_same<T, LowStringPtr>::value) {
+  if constexpr (std::is_same<T, const StringData*>::value) {
     auto const lo = decode_as_bytes<uint32_t>(buffer, pos);
     if (!(lo & kStringDataFlag)) {
-      return LowStringPtr(reinterpret_cast<const StringData*>(lo));
+      return reinterpret_cast<const StringData*>(lo);
     }
     auto const hi = decode_as_bytes<uint32_t>(buffer, pos);
     auto const both = (uint64_t(hi) << 32) | (uint64_t(lo) & ~kStringDataFlag);
-    return LowStringPtr(reinterpret_cast<const StringData*>(both));
+    return reinterpret_cast<const StringData*>(both);
   }
 
   if constexpr (std::is_same<T, MKey>::value) {
@@ -264,9 +262,9 @@ void encode(Buffer& buffer, const T& data) {
     encode(buffer, data.first);
     encode(buffer, data.count);
 
-  } else if constexpr (std::is_same<T, LowStringPtr>::value) {
+  } else if constexpr (std::is_same<T, const StringData*>::value) {
     static_assert(alignof(StringData) % 2 == 0);
-    auto const raw = uintptr_t(data.get());
+    auto const raw = uintptr_t(data);
     if (raw <= std::numeric_limits<uint32_t>::max()) {
       encode_as_bytes(buffer, safe_cast<uint32_t>(raw));
     } else {