[llvm] r354599 - [WebAssembly] Don't create MSSymbolWasm object for non-symbols

[Sam Clegg via llvm-commits]

Author: sbc
Date: Thu Feb 21 09:05:19 2019
New Revision: 354599

URL: http://llvm.org/viewvc/llvm-project?rev=354599&view=rev
Log:
[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

Modified:
    llvm/trunk/lib/MC/WasmObjectWriter.cpp

Modified: llvm/trunk/lib/MC/WasmObjectWriter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/WasmObjectWriter.cpp?rev=354599&r1=354598&r2=354599&view=diff
==============================================================================
--- llvm/trunk/lib/MC/WasmObjectWriter.cpp (original)
+++ llvm/trunk/lib/MC/WasmObjectWriter.cpp Thu Feb 21 09:05:19 2019
@@ -1148,7 +1148,6 @@ uint64_t WasmObjectWriter::writeObject(M
   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(M
   // 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);