[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.

lld/wasm/OutputSections.cpp

 // Returns a string, e.g. "FUNCTION(.text)".
 std::string toString(const wasm::OutputSection &sec) {
   if (!sec.name.empty())
     return (sec.getSectionName() + "(" + sec.name + ")").str();
   return std::string(sec.getSectionName());
 }
 
 namespace wasm {
-static StringRef sectionTypeToString(uint32_t sectionType) {
-  switch (sectionType) {
-  case WASM_SEC_CUSTOM:
-    return "CUSTOM";
-  case WASM_SEC_TYPE:
-    return "TYPE";
-  case WASM_SEC_IMPORT:
-    return "IMPORT";
-  case WASM_SEC_FUNCTION:
-    return "FUNCTION";
-  case WASM_SEC_TABLE:
-    return "TABLE";
-  case WASM_SEC_MEMORY:
-    return "MEMORY";
-  case WASM_SEC_GLOBAL:
-    return "GLOBAL";
-  case WASM_SEC_TAG:
-    return "TAG";
-  case WASM_SEC_EXPORT:
-    return "EXPORT";
-  case WASM_SEC_START:
-    return "START";
-  case WASM_SEC_ELEM:
-    return "ELEM";
-  case WASM_SEC_CODE:
-    return "CODE";
-  case WASM_SEC_DATA:
-    return "DATA";
-  case WASM_SEC_DATACOUNT:
-    return "DATACOUNT";
-  default:
-    fatal("invalid section type");
-  }
-}
-
 StringRef OutputSection::getSectionName() const {
   return sectionTypeToString(type);
 }
 
 void OutputSection::createHeader(size_t bodySize) {
   raw_string_ostream os(header);
   debugWrite(os.tell(), "section type [" + getSectionName() + "]");
   encodeULEB128(type, os);

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");
   }
 }
 
+llvm::StringRef llvm::wasm::sectionTypeToString(uint32_t Type) {
+#define ECase(X)                                                               \
+  case wasm::WASM_SEC_##X:                                                     \
+    return #X;
+  switch (Type) {
+    ECase(CUSTOM);
+    ECase(TYPE);
+    ECase(IMPORT);
+    ECase(FUNCTION);
+    ECase(TABLE);
+    ECase(MEMORY);
+    ECase(GLOBAL);
+    ECase(EXPORT);
+    ECase(START);
+    ECase(ELEM);
+    ECase(CODE);
+    ECase(DATA);
+    ECase(DATACOUNT);
+    ECase(TAG);
+  default:
+    llvm_unreachable("unknown section type");
+  }
+#undef ECase
+}
+
 bool llvm::wasm::relocTypeHasAddend(uint32_t Type) {
   switch (Type) {
   case R_WASM_MEMORY_ADDR_LEB:
   case R_WASM_MEMORY_ADDR_LEB64:
   case R_WASM_MEMORY_ADDR_SLEB:
   case R_WASM_MEMORY_ADDR_SLEB64:
   case R_WASM_MEMORY_ADDR_REL_SLEB:
   case R_WASM_MEMORY_ADDR_REL_SLEB64:

llvm/lib/Object/WasmObjectFile.cpp

default:
     llvm_unreachable("unknown WasmSymbol::SymbolType");
   }
 }
 
 void WasmObjectFile::moveSectionNext(DataRefImpl &Sec) const { Sec.d.a++; }
 
 Expected<StringRef> WasmObjectFile::getSectionName(DataRefImpl Sec) const {
   const WasmSection &S = Sections[Sec.d.a];
-#define ECase(X)                                                               \
-  case wasm::WASM_SEC_##X:                                                     \
-    return #X;
-  switch (S.Type) {
-    ECase(TYPE);
-    ECase(IMPORT);
-    ECase(FUNCTION);
-    ECase(TABLE);
-    ECase(MEMORY);
-    ECase(GLOBAL);
-    ECase(TAG);
-    ECase(EXPORT);
-    ECase(START);
-    ECase(ELEM);
-    ECase(CODE);
-    ECase(DATA);
-    ECase(DATACOUNT);
-  case wasm::WASM_SEC_CUSTOM:
+  if (S.Type == wasm::WASM_SEC_CUSTOM)
     return S.Name;
-  default:
+  if (S.Type > wasm::WASM_SEC_TAG)
     return createStringError(object_error::invalid_section_index, "");
-  }
-#undef ECase
+  return wasm::sectionTypeToString(S.Type);
 }
 
 uint64_t WasmObjectFile::getSectionAddress(DataRefImpl Sec) const { return 0; }
 
 uint64_t WasmObjectFile::getSectionIndex(DataRefImpl Sec) const {
   return Sec.d.a;
 }