[WebAssembly] Fix local references to weak aliases

When weak aliases are used with in same translation
unit we need to be able to directly reference to alias
and not just the thing it is aliases.  We do this by
defining both a wasm import and a wasm export in this
case that result in a single Symbol.  This change is
a partial revert of rL314245.  A corresponding lld
change address the previous issues we had with this.

See: https://github.com/WebAssembly/tool-conventions/issues/34

Differential Revision: https://reviews.llvm.org/D41472

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@321242 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 15 insertions, 6 deletions

diff --git a/include/llvm/Object/Wasm.h b/include/llvm/Object/Wasm.h
index 5bb1a3fca3d1..71951d83f3cc 100644
--- a/include/llvm/Object/Wasm.h
+++ b/include/llvm/Object/Wasm.h
@@ -43,9 +43,9 @@ public:
   };
 
   WasmSymbol(StringRef Name, SymbolType Type, uint32_t Section,
-             uint32_t ElementIndex, uint32_t ImportIndex = 0)
+             uint32_t ElementIndex, uint32_t FunctionType = 0)
       : Name(Name), Type(Type), Section(Section), ElementIndex(ElementIndex),
-        ImportIndex(ImportIndex) {}
+        FunctionType(FunctionType) {}
 
   StringRef Name;
   SymbolType Type;
@@ -55,8 +55,18 @@ public:
   // Index into either the function or global index space.
   uint32_t ElementIndex;
 
-  // For imports, the index into the import table
-  uint32_t ImportIndex;
+  // For function, the type index
+  uint32_t FunctionType;
+
+  // Symbols can be both exported and imported (in the case of the weakly
+  // defined symbol).  In this the import index is stored as AltIndex.
+  uint32_t AltIndex = 0;
+  bool HasAltIndex = false;
+
+  void setAltIndex(uint32_t Index) {
+    HasAltIndex = true;
+    AltIndex = Index;
+  }
 
   bool isFunction() const {
     return Type == WasmSymbol::SymbolType::FUNCTION_IMPORT ||
@@ -91,8 +101,7 @@ public:
 
   void print(raw_ostream &Out) const {
     Out << "Name=" << Name << ", Type=" << static_cast<int>(Type)
-        << ", Flags=" << Flags << " ElemIndex=" << ElementIndex
-        << ", ImportIndex=" << ImportIndex;
+        << ", Flags=" << Flags << " ElemIndex=" << ElementIndex;
   }
 
 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)