add comments

Author: dschuff

llvm/include/llvm/BinaryFormat/Wasm.h

@@ -467,10 +467,15 @@ struct WasmDebugName {
   StringRef Name;
 };
 
+// Info from the linking metadata section of a wasm object file.
 struct WasmLinkingData {
   uint32_t Version;
   std::vector<WasmInitFunc> InitFunctions;
   std::vector<StringRef> Comdats;
+  // The linking section also contains a symbol table. This info (represented
+  // in a WasmSymbolInfo struct) is stored inside the WasmSymbol object instead
+  // of in this structure; this allows vectors of WasmSymbols and
+  // WasmLinkingDatas to be reallocated.
 };
 
 struct WasmSignature {

llvm/include/llvm/Object/Wasm.h

@@ -43,6 +43,8 @@ class WasmSymbol {
     assert(!Signature || Signature->Kind != wasm::WasmSignature::Placeholder);
   }
 
+  // Symbol info as represented in the symbol's 'syminfo' entry of an object
+  // file's symbol table.
   const wasm::WasmSymbolInfo Info;
   const wasm::WasmGlobalType *GlobalType;
   const wasm::WasmTableType *TableType;