[WebAssebmly] Add Module name to WasmSymbol

Imports in a wasm module can have custom module name.  This change
adds the module name to the WasmSymbol structure so that the linker
can preserve this module name.

This is needed to fix: https://bugs.llvm.org/show_bug.cgi?id=37168

Differential Revision: https://reviews.llvm.org/D45797

llvm-svn: 330854

llvm/include/llvm/BinaryFormat/Wasm.h

@@ -145,6 +145,7 @@ struct WasmSymbolInfo {
   StringRef Name;
   uint8_t Kind;
   uint32_t Flags;
+  StringRef Module; // For undefined symbols the module name of the import
   union {
     // For function or global symbols, the index in function or global index
     // space.

llvm/lib/Object/WasmObjectFile.cpp

@@ -412,6 +412,7 @@ Error WasmObjectFile::parseLinkingSectionSymtab(const uint8_t *&Ptr,
         wasm::WasmImport &Import = *ImportedFunctions[Info.ElementIndex];
         FunctionType = &Signatures[Import.SigIndex];
         Info.Name = Import.Field;
+        Info.Module = Import.Module;
       }
       break;