[WebAssembly] Use toArrayRef. NFC.

[ruiu]

Summary

[WebAssembly] Use toArrayRef. NFC.

wasm/Writer.cpp

 #include "InputChunks.h"
 #include "InputGlobal.h"
 #include "OutputSections.h"
 #include "OutputSegment.h"
 #include "SymbolTable.h"
 #include "WriterUtils.h"
 #include "lld/Common/ErrorHandler.h"
 #include "lld/Common/Memory.h"
+#include "lld/Common/Strings.h"
 #include "lld/Common/Threads.h"
 #include "llvm/ADT/DenseSet.h"
 #include "llvm/BinaryFormat/Wasm.h"
 #include "llvm/Support/FileOutputBuffer.h"
 #include "llvm/Support/Format.h"
 #include "llvm/Support/FormatVariadic.h"
 #include "llvm/Support/LEB128.h"
 

 // Create synthetic "__wasm_call_ctors" function based on ctor functions
 // in input object.
 void Writer::createCtorFunction() {
   uint32_t FunctionIndex = NumImportedFunctions + InputFunctions.size();
   WasmSym::CallCtors->setOutputIndex(FunctionIndex);
 
   // First write the body bytes to a string.
   std::string FunctionBody;
-  const WasmSignature *Signature = WasmSym::CallCtors->getFunctionType();
   {
     raw_string_ostream OS(FunctionBody);
     writeUleb128(OS, 0, "num locals");
     for (const WasmInitEntry &F : InitFunctions) {
       writeU8(OS, OPCODE_CALL, "CALL");
       writeUleb128(OS, F.Sym->getOutputIndex(), "function index");
     }
     writeU8(OS, OPCODE_END, "END");
   }
 
   // Once we know the size of the body we can create the final function body
   raw_string_ostream OS(CtorFunctionBody);
   writeUleb128(OS, FunctionBody.size(), "function size");
   OS.flush();
   CtorFunctionBody += FunctionBody;
-  ArrayRef<uint8_t> BodyArray(
-      reinterpret_cast<const uint8_t *>(CtorFunctionBody.data()),
-      CtorFunctionBody.size());
-  SyntheticFunction *F = make<SyntheticFunction>(*Signature, BodyArray,
-                                                 WasmSym::CallCtors->getName());
+
+  const WasmSignature *Sig = WasmSym::CallCtors->getFunctionType();
+  SyntheticFunction *F = make<SyntheticFunction>(
+      *Sig, toArrayRef(CtorFunctionBody), WasmSym::CallCtors->getName());
+
   F->setOutputIndex(FunctionIndex);
   F->Live = true;
   WasmSym::CallCtors->Function = F;
   InputFunctions.emplace_back(F);
 }
 
 // Populate InitFunctions vector with init functions from all input objects.
 // This is then used either when creating the output linking section or to