[WebAssembly] Check signatures of weakly defined funtions too

Subscribers: jfb, dschuff, jgravelle-google, aheejin, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D43492

llvm-svn: 325598
diff --git a/lld/wasm/SymbolTable.cpp b/lld/wasm/SymbolTable.cpp
index 0fb60bb..c46d6ca 100644
--- a/lld/wasm/SymbolTable.cpp
+++ b/lld/wasm/SymbolTable.cpp
@@ -175,6 +175,7 @@
   } else if ((Flags & WASM_SYMBOL_BINDING_MASK) == WASM_SYMBOL_BINDING_WEAK) {
     // the new symbol is weak we can ignore it
     DEBUG(dbgs() << "existing symbol takes precedence\n");
+    CheckTypes = true;
   } else if (S->isWeak()) {
     // the existing symbol is, so we replace it
     DEBUG(dbgs() << "replacing existing weak symbol\n");