[WebAssembly] Add explicit symbol table

This change modified lld to in response the llvm change which
moved to a more explicit symbol table in the object format.

Based on patches by Nicholas Wilson:
 1. https://reviews.llvm.org/D41955
 2. https://reviews.llvm.org/D42585

The primary difference that we see in the test output is that
for relocatable (-r) output we now have symbol table which
replaces exports/imports and globals.

See: https://github.com/WebAssembly/tool-conventions/issues/38
Differential Revision: https://reviews.llvm.org/D43264

llvm-svn: 325861

1 files changed, 52 insertions, 0 deletions

diff --git a/lld/wasm/InputGlobal.h b/lld/wasm/InputGlobal.h
new file mode 100644
index 00000000000..53af220e827
--- /dev/null
+++ b/lld/wasm/InputGlobal.h
@@ -0,0 +1,52 @@
+//===- InputGlobal.h --------------------------------------------*- C++ -*-===//
+//
+//                             The LLVM Linker
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLD_WASM_INPUT_GLOBAL_H
+#define LLD_WASM_INPUT_GLOBAL_H
+
+#include "Config.h"
+#include "InputFiles.h"
+#include "WriterUtils.h"
+#include "lld/Common/ErrorHandler.h"
+#include "llvm/Object/Wasm.h"
+
+using llvm::wasm::WasmGlobal;
+using llvm::wasm::WasmInitExpr;
+
+namespace lld {
+namespace wasm {
+
+// Represents a single Wasm Global Variable within an input file. These are
+// combined to form the final GLOBALS section.
+class InputGlobal {
+public:
+  InputGlobal(const WasmGlobal &G) : Global(G) {}
+
+  const WasmGlobalType &getType() const { return Global.Type; }
+
+  uint32_t getOutputIndex() const { return OutputIndex.getValue(); }
+  bool hasOutputIndex() const { return OutputIndex.hasValue(); }
+  void setOutputIndex(uint32_t Index) {
+    assert(!hasOutputIndex());
+    OutputIndex = Index;
+  }
+
+  bool Live = false;
+
+  WasmGlobal Global;
+
+protected:
+  llvm::Optional<uint32_t> OutputIndex;
+};
+
+} // namespace wasm
+
+} // namespace lld
+
+#endif // LLD_WASM_INPUT_GLOBAL_H