[clang][bytecode] Don't memcpy() FixedPoint values (#123599)

llvm::FixedPoint is not trivially copyable.

Author: tbaederr

clang/lib/AST/ByteCode/ByteCodeEmitter.cpp

@@ -332,6 +332,12 @@ void emit(Program &P, std::vector<std::byte> &Code, const IntegralAP<true> &Val,
   emitSerialized(Code, Val, Success);
 }
 
+template <>
+void emit(Program &P, std::vector<std::byte> &Code, const FixedPoint &Val,
+          bool &Success) {
+  emitSerialized(Code, Val, Success);
+}
+
 template <typename... Tys>
 bool ByteCodeEmitter::emitOp(Opcode Op, const Tys &...Args,
                              const SourceInfo &SI) {

clang/lib/AST/ByteCode/Disasm.cpp

@@ -62,6 +62,12 @@ inline IntegralAP<true> ReadArg<IntegralAP<true>>(Program &P, CodePtr &OpPC) {
   return I;
 }
 
+template <> inline FixedPoint ReadArg<FixedPoint>(Program &P, CodePtr &OpPC) {
+  FixedPoint I = FixedPoint::deserialize(*OpPC);
+  OpPC += align(I.bytesToSerialize());
+  return I;
+}
+
 LLVM_DUMP_METHOD void Function::dump() const { dump(llvm::errs()); }
 
 LLVM_DUMP_METHOD void Function::dump(llvm::raw_ostream &OS) const {

clang/lib/AST/ByteCode/FixedPoint.h

@@ -91,6 +91,32 @@ class FixedPoint final {
     return ComparisonCategoryResult::Greater;
   }
 
+  size_t bytesToSerialize() const {
+    return sizeof(uint32_t) + (V.getValue().getBitWidth() / CHAR_BIT);
+  }
+
+  void serialize(std::byte *Buff) const {
+    // Semantics followed by APInt.
+    uint32_t SemI = V.getSemantics().toOpaqueInt();
+    std::memcpy(Buff, &SemI, sizeof(SemI));
+
+    llvm::APInt API = V.getValue();
+    llvm::StoreIntToMemory(API, (uint8_t *)(Buff + sizeof(SemI)),
+                           bitWidth() / 8);
+  }
+
+  static FixedPoint deserialize(const std::byte *Buff) {
+    auto Sem = llvm::FixedPointSemantics::getFromOpaqueInt(
+        *reinterpret_cast<const uint32_t *>(Buff));
+    unsigned BitWidth = Sem.getWidth();
+    APInt I(BitWidth, 0ull, !Sem.isSigned());
+    llvm::LoadIntFromMemory(
+        I, reinterpret_cast<const uint8_t *>(Buff + sizeof(uint32_t)),
+        BitWidth / CHAR_BIT);
+
+    return FixedPoint(I, Sem);
+  }
+
   static bool neg(const FixedPoint &A, FixedPoint *R) {
     bool Overflow = false;
     *R = FixedPoint(A.V.negate(&Overflow));

clang/lib/AST/ByteCode/Interp.h

@@ -3070,6 +3070,13 @@ inline IntegralAP<true> ReadArg<IntegralAP<true>>(InterpState &S,
   return I;
 }
 
+template <>
+inline FixedPoint ReadArg<FixedPoint>(InterpState &S, CodePtr &OpPC) {
+  FixedPoint FP = FixedPoint::deserialize(*OpPC);
+  OpPC += align(FP.bytesToSerialize());
+  return FP;
+}
+
 } // namespace interp
 } // namespace clang