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

`__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.

Differential Revision: https://reviews.llvm.org/D58487

llvm-svn: 354599

1 files changed, 4 insertions, 9 deletions

diff --git a/llvm/lib/MC/WasmObjectWriter.cpp b/llvm/lib/MC/WasmObjectWriter.cpp
index 10f16ba..d8dfc57 100644
--- a/llvm/lib/MC/WasmObjectWriter.cpp
+++ b/llvm/lib/MC/WasmObjectWriter.cpp
@@ -1148,7 +1148,6 @@ uint64_t WasmObjectWriter::writeObject(MCAssembler &Asm,
   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 @@ uint64_t WasmObjectWriter::writeObject(MCAssembler &Asm,
   // 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);