[WebAssembly] Consolidate sectionTypeToString in BinaryFormat [NFC]

[dschuff]

Summary

Currently there are 2 duplicate implementation, and I want to add
a use in a 3rd place. Combine them in lib/BinaryFormat so they can
be shared.

Also update the return values of the reloc and symbol type toString functions to use StringRef.

[sbc100]

llvm/include/llvm/BinaryFormat/Wasm.h

474

Use std::string for consistency with the two above? Or convert them all the StringRef?

[dschuff]

llvm/include/llvm/BinaryFormat/Wasm.h

474

I had originally planned that for after D126509 but I guess since this is now just a pure refactor, we can add it in. As I said there, IMO StringRef would be better since the backing store is just a static const char* and then we wouldn't need to copy. But I'll check whether any of the uses of relocTypeToString and toString really do need to be std::string.

[dschuff]

also update reloc and symbol type functions

[dschuff]

include all the diffs

llvm/include/llvm/BinaryFormat/Wasm.h

474

OK, they're all stringref now, no callsite changes were needed.

llvm/include/llvm/BinaryFormat/Wasm.h

return LHS.Flags == RHS.Flags && LHS.Minimum == RHS.Minimum &&
          (LHS.Flags & WASM_LIMITS_FLAG_HAS_MAX ? LHS.Maximum == RHS.Maximum
                                                : true);
 }
 
 inline bool operator==(const WasmTableType &LHS, const WasmTableType &RHS) {
   return LHS.ElemType == RHS.ElemType && LHS.Limits == RHS.Limits;
 }
 
-std::string toString(WasmSymbolType type);
-std::string relocTypetoString(uint32_t type);
+llvm::StringRef toString(WasmSymbolType type);
+llvm::StringRef relocTypetoString(uint32_t type);
 llvm::StringRef sectionTypeToString(uint32_t type);
 bool relocTypeHasAddend(uint32_t type);
 
 } // end namespace wasm
 } // end namespace llvm
 
 #endif

llvm/lib/BinaryFormat/Wasm.cpp

 //===-- llvm/BinaryFormat/Wasm.cpp -------------------------------*- C++-*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #include "llvm/BinaryFormat/Wasm.h"
 
-std::string llvm::wasm::toString(wasm::WasmSymbolType Type) {
+llvm::StringRef llvm::wasm::toString(wasm::WasmSymbolType Type) {
   switch (Type) {
   case wasm::WASM_SYMBOL_TYPE_FUNCTION:
     return "WASM_SYMBOL_TYPE_FUNCTION";
   case wasm::WASM_SYMBOL_TYPE_GLOBAL:
     return "WASM_SYMBOL_TYPE_GLOBAL";
   case wasm::WASM_SYMBOL_TYPE_TABLE:
     return "WASM_SYMBOL_TYPE_TABLE";
   case wasm::WASM_SYMBOL_TYPE_DATA:
     return "WASM_SYMBOL_TYPE_DATA";
   case wasm::WASM_SYMBOL_TYPE_SECTION:
     return "WASM_SYMBOL_TYPE_SECTION";
   case wasm::WASM_SYMBOL_TYPE_TAG:
     return "WASM_SYMBOL_TYPE_TAG";
   }
   llvm_unreachable("unknown symbol type");
 }
 
-std::string llvm::wasm::relocTypetoString(uint32_t Type) {
+llvm::StringRef llvm::wasm::relocTypetoString(uint32_t Type) {
   switch (Type) {
 #define WASM_RELOC(NAME, VALUE)                                                \
   case VALUE:                                                                  \
     return #NAME;
 #include "llvm/BinaryFormat/WasmRelocs.def"
 #undef WASM_RELOC
   default:
     llvm_unreachable("unknown reloc type");