[lld] [llvm] [WebAssembly][Object] Support more elem segment flags (PR #123427)

[Derek Schuff via llvm-commits]

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@@ -1440,15 +1440,20 @@ Error WasmObjectFile::parseExportSection(ReadContext &Ctx) {
     Info.Flags = 0;
     switch (Ex.Kind) {
     case wasm::WASM_EXTERNAL_FUNCTION: {
-      if (!isDefinedFunctionIndex(Ex.Index))
+      if (!isValidFunctionIndex(Ex.Index))
         return make_error<GenericBinaryError>("invalid function export",
                                               object_error::parse_failed);
-      getDefinedFunction(Ex.Index).ExportName = Ex.Name;
       Info.Kind = wasm::WASM_SYMBOL_TYPE_FUNCTION;
       Info.ElementIndex = Ex.Index;
-      unsigned FuncIndex = Info.ElementIndex - NumImportedFunctions;
-      wasm::WasmFunction &Function = Functions[FuncIndex];
-      Signature = &Signatures[Function.SigIndex];
+      if (isDefinedFunctionIndex(Ex.Index)) {
+        getDefinedFunction(Ex.Index).ExportName = Ex.Name;
+        unsigned FuncIndex = Info.ElementIndex - NumImportedFunctions;
+        wasm::WasmFunction &Function = Functions[FuncIndex];
+        Signature = &Signatures[Function.SigIndex];
+      }
+      // Else the function is imported. LLVM object files don't use this
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dschuff wrote:

There's no actual else clause here, we don't do anything in this case. There's no s signature info to look up, so we just push what we have into the exports list.

https://github.com/llvm/llvm-project/pull/123427