[PATCH] D58487: [WebAssembly] Don't create MSSymbolWasm object for non-symbols

[Sam Clegg via Phabricator via llvm-commits]

sbc100 created this revision.
Herald added subscribers: llvm-commits, sunfish, aheejin, hiraditya, jgravelle-google, dschuff.
Herald added a project: LLVM.

`__linear_memory` and `__indirect_function_table` are both generated
as imports in wasm object files but are actually symbols and don't
appear in any symbols table or relocation entry.  Indeed we
don't have any symbol type to meaningfully represent either of them.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D58487

Files:
  llvm/lib/MC/WasmObjectWriter.cpp


Index: llvm/lib/MC/WasmObjectWriter.cpp
===================================================================
--- llvm/lib/MC/WasmObjectWriter.cpp
+++ llvm/lib/MC/WasmObjectWriter.cpp
@@ -1148,7 +1148,6 @@
   uint64_t StartOffset = W.OS.tell();
 
   LLVM_DEBUG(dbgs() << "WasmObjectWriter::writeObject\n");
-  MCContext &Ctx = Asm.getContext();
 
   // Collect information from the available symbols.
   SmallVector<WasmFunction, 4> Functions;
@@ -1164,22 +1163,18 @@
   // For now, always emit the memory import, since loads and stores are not
   // valid without it. In the future, we could perhaps be more clever and omit
   // it if there are no loads or stores.
-  auto *MemorySym =
-      cast<MCSymbolWasm>(Ctx.getOrCreateSymbol("__linear_memory"));
   wasm::WasmImport MemImport;
-  MemImport.Module = MemorySym->getImportModule();
-  MemImport.Field = MemorySym->getImportName();
+  MemImport.Module = "env";
+  MemImport.Field = "__linear_memory";
   MemImport.Kind = wasm::WASM_EXTERNAL_MEMORY;
   Imports.push_back(MemImport);
 
   // For now, always emit the table section, since indirect calls are not
   // valid without it. In the future, we could perhaps be more clever and omit
   // it if there are no indirect calls.
-  auto *TableSym =
-      cast<MCSymbolWasm>(Ctx.getOrCreateSymbol("__indirect_function_table"));
   wasm::WasmImport TableImport;
-  TableImport.Module = TableSym->getImportModule();
-  TableImport.Field = TableSym->getImportName();
+  TableImport.Module = "env";
+  TableImport.Field = "__indirect_function_table";
   TableImport.Kind = wasm::WASM_EXTERNAL_TABLE;
   TableImport.Table.ElemType = wasm::WASM_TYPE_FUNCREF;
   Imports.push_back(TableImport);


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