[WebAssembly] Use uint8_t for single byte values to match the spec

[sbc100]

Summary

See https://reviews.llvm.org/D43921

See https://github.com/WebAssembly/wabt/pull/782

[sbc100]

• rebase

[ruiu]

LGTM

wasm/Writer.cpp

void Writer::createTableSection() {
   //     a validation error to include a call_indirect instruction if there
   //     is not table.
   uint32_t TableSize = kInitialTableOffset + IndirectFunctions.size();
 
   SyntheticSection *Section = createSyntheticSection(WASM_SEC_TABLE);
   raw_ostream &OS = Section->getStream();
 
   writeUleb128(OS, 1, "table count");
-  writeSleb128(OS, WASM_TYPE_ANYFUNC, "table type");
+  writeU8(OS, WASM_TYPE_ANYFUNC, "table type");
   writeUleb128(OS, WASM_LIMITS_FLAG_HAS_MAX, "table flags");
   writeUleb128(OS, TableSize, "table initial size");
   writeUleb128(OS, TableSize, "table max size");
 }
 
 void Writer::createExportSection() {
   bool ExportMemory = !Config->Relocatable && !Config->ImportMemory;
 
if (!SymtabEntries.empty()) {
     SubSection Sub(WASM_SYMBOL_TABLE);
     writeUleb128(Sub.OS, SymtabEntries.size(), "num symbols");
 
     for (const Symbol *Sym : SymtabEntries) {
       assert(Sym->isDefined() || Sym->isUndefined());
       WasmSymbolType Kind = Sym->getWasmType();
       uint32_t Flags = getWasmFlags(Sym);
 
-      writeUleb128(Sub.OS, Kind, "sym kind");
+      writeU8(Sub.OS, Kind, "sym kind");
       writeUleb128(Sub.OS, Flags, "sym flags");
 
       switch (Kind) {
       case llvm::wasm::WASM_SYMBOL_TYPE_FUNCTION:
       case llvm::wasm::WASM_SYMBOL_TYPE_GLOBAL:
         writeUleb128(Sub.OS, Sym->getOutputIndex(), "index");
         if (Sym->isDefined())
           writeStr(Sub.OS, Sym->getName(), "sym name");
#endif
   if (!Comdats.empty()) {
     SubSection Sub(WASM_COMDAT_INFO);
     writeUleb128(Sub.OS, Comdats.size(), "num comdats");
     for (const auto &C : Comdats) {
       writeStr(Sub.OS, C.first, "comdat name");
       writeUleb128(Sub.OS, 0, "comdat flags"); // flags for future use
       writeUleb128(Sub.OS, C.second.size(), "num entries");
       for (const ComdatEntry &Entry : C.second) {
-        writeUleb128(Sub.OS, Entry.Kind, "entry kind");
+        writeU8(Sub.OS, Entry.Kind, "entry kind");
         writeUleb128(Sub.OS, Entry.Index, "entry index");
       }
     }
     Sub.writeTo(OS);
   }
 }
 
 // Create the custom "name" section containing debug symbol names.

wasm/WriterUtils.h

inline bool operator!=(const llvm::wasm::WasmGlobalType &LHS,
   return !(LHS == RHS);
 }
 
 namespace lld {
 namespace wasm {
 
 void debugWrite(uint64_t Offset, const Twine &Msg);
 
-void writeUleb128(raw_ostream &OS, uint32_t Number, StringRef Msg);
+void writeUleb128(raw_ostream &OS, uint32_t Number, const Twine &Msg);
 
-void writeSleb128(raw_ostream &OS, int32_t Number, StringRef Msg);
+void writeSleb128(raw_ostream &OS, int32_t Number, const Twine &Msg);
 
-void writeBytes(raw_ostream &OS, const char *Bytes, size_t count, StringRef Msg);
+void writeBytes(raw_ostream &OS, const char *Bytes, size_t count, const Twine &Msg);
 
-void writeStr(raw_ostream &OS, StringRef String, StringRef Msg);
+void writeStr(raw_ostream &OS, StringRef String, const Twine &Msg);
 
-void writeU8(raw_ostream &OS, uint8_t byte, StringRef Msg);
+void writeU8(raw_ostream &OS, uint8_t byte, const Twine &Msg);
 
-void writeU32(raw_ostream &OS, uint32_t Number, StringRef Msg);
+void writeU32(raw_ostream &OS, uint32_t Number, const Twine &Msg);
 
-void writeValueType(raw_ostream &OS, int32_t Type, StringRef Msg);
+void writeValueType(raw_ostream &OS, uint8_t Type, const Twine &Msg);
 
 void writeSig(raw_ostream &OS, const llvm::wasm::WasmSignature &Sig);
 
 void writeInitExpr(raw_ostream &OS, const llvm::wasm::WasmInitExpr &InitExpr);
 
 void writeLimits(raw_ostream &OS, const llvm::wasm::WasmLimits &Limits);
 
 void writeGlobalType(raw_ostream &OS, const llvm::wasm::WasmGlobalType &Type);

wasm/WriterUtils.cpp

 }
 
 namespace lld {
 
 void wasm::debugWrite(uint64_t Offset, const Twine &Msg) {
   DEBUG(dbgs() << format("  | %08lld: ", Offset) << Msg << "\n");
 }
 
-void wasm::writeUleb128(raw_ostream &OS, uint32_t Number, StringRef Msg) {
+void wasm::writeUleb128(raw_ostream &OS, uint32_t Number, const Twine &Msg) {
   debugWrite(OS.tell(), Msg + "[" + utohexstr(Number) + "]");
   encodeULEB128(Number, OS);
 }
 
-void wasm::writeSleb128(raw_ostream &OS, int32_t Number, StringRef Msg) {
+void wasm::writeSleb128(raw_ostream &OS, int32_t Number, const Twine &Msg) {
   debugWrite(OS.tell(), Msg + "[" + utohexstr(Number) + "]");
   encodeSLEB128(Number, OS);
 }
 
 void wasm::writeBytes(raw_ostream &OS, const char *Bytes, size_t Count,
-                      StringRef Msg) {
+                      const Twine &Msg) {
   debugWrite(OS.tell(), Msg + " [data[" + Twine(Count) + "]]");
   OS.write(Bytes, Count);
 }
 
-void wasm::writeStr(raw_ostream &OS, StringRef String, StringRef Msg) {
+void wasm::writeStr(raw_ostream &OS, StringRef String, const Twine &Msg) {
   debugWrite(OS.tell(),
              Msg + " [str[" + Twine(String.size()) + "]: " + String + "]");
   encodeULEB128(String.size(), OS);
   OS.write(String.data(), String.size());
 }
 
-void wasm::writeU8(raw_ostream &OS, uint8_t Byte, StringRef Msg) { OS << Byte; }
+void wasm::writeU8(raw_ostream &OS, uint8_t Byte, const Twine &Msg) {
+  debugWrite(OS.tell(), Msg + " [0x" + utohexstr(Byte) + "]");
+  OS << Byte;
+}
 
-void wasm::writeU32(raw_ostream &OS, uint32_t Number, StringRef Msg) {
+void wasm::writeU32(raw_ostream &OS, uint32_t Number, const Twine &Msg) {
   debugWrite(OS.tell(), Msg + "[" + utohexstr(Number) + "]");
   support::endian::Writer<support::little>(OS).write(Number);
 }
 
-void wasm::writeValueType(raw_ostream &OS, int32_t Type, StringRef Msg) {
-  debugWrite(OS.tell(), Msg + "[type: " + valueTypeToString(Type) + "]");
-  encodeSLEB128(Type, OS);
+void wasm::writeValueType(raw_ostream &OS, uint8_t Type, const Twine &Msg) {
+  writeU8(OS, Type, Twine(Msg) + "[type: " + valueTypeToString(Type) + "]");
 }
 
 void wasm::writeSig(raw_ostream &OS, const WasmSignature &Sig) {
-  writeSleb128(OS, WASM_TYPE_FUNC, "signature type");
+  writeU8(OS, WASM_TYPE_FUNC, "signature type");
   writeUleb128(OS, Sig.ParamTypes.size(), "param Count");
-  for (int32_t ParamType : Sig.ParamTypes) {
+
+  for (uint8_t ParamType : Sig.ParamTypes)
     writeValueType(OS, ParamType, "param type");
-  }
+
   if (Sig.ReturnType == WASM_TYPE_NORESULT) {
-    writeUleb128(OS, 0, "result Count");
+    writeU8(OS, 0, "result Count");
   } else {
-    writeUleb128(OS, 1, "result Count");
+    writeU8(OS, 1, "result Count");
     writeValueType(OS, Sig.ReturnType, "result type");
   }
 }
 
 void wasm::writeInitExpr(raw_ostream &OS, const WasmInitExpr &InitExpr) {
   writeU8(OS, InitExpr.Opcode, "opcode");
   switch (InitExpr.Opcode) {
   case WASM_OPCODE_I32_CONST: