[lld] Fix trivial typos in comments

Reviewed By: ruiu, MaskRay

Differential Revision: https://reviews.llvm.org/D72196
diff --git a/lld/wasm/SymbolTable.cpp b/lld/wasm/SymbolTable.cpp
index 14616f9..598859d 100644
--- a/lld/wasm/SymbolTable.cpp
+++ b/lld/wasm/SymbolTable.cpp
@@ -203,8 +203,9 @@
 }
 
 // Adds an optional, linker generated, data symbols.  The symbol will only be
-// added if there is an undefine reference to it, or if it is explictly exported
-// via the --export flag.  Otherwise we don't add the symbol and return nullptr.
+// added if there is an undefine reference to it, or if it is explicitly
+// exported via the --export flag.  Otherwise we don't add the symbol and return
+// nullptr.
 DefinedData *SymbolTable::addOptionalDataSymbol(StringRef name,
                                                 uint32_t value) {
   Symbol *s = find(name);
@@ -396,7 +397,7 @@
 // This function get called when an undefined symbol is added, and there is
 // already an existing one in the symbols table.  In this case we check that
 // custom 'import-module' and 'import-field' symbol attributes agree.
-// With LTO these attributes are not avialable when the bitcode is read and only
+// With LTO these attributes are not available when the bitcode is read and only
 // become available when the LTO object is read.  In this case we silently
 // replace the empty attributes with the valid ones.
 template <typename T>
@@ -533,7 +534,7 @@
     return;
 
   // The existing symbol is undefined, load a new one from the archive,
-  // unless the the existing symbol is weak in which case replace the undefined
+  // unless the existing symbol is weak in which case replace the undefined
   // symbols with a LazySymbol.
   if (s->isWeak()) {
     const WasmSignature *oldSig = nullptr;
@@ -646,7 +647,7 @@
       // It is possible for undefined functions not to have a signature (eg. if
       // added via "--undefined"), but weak undefined ones do have a signature.
       // Lazy symbols may not be functions and therefore Sig can still be null
-      // in some circumstantce.
+      // in some circumstance.
       assert(!isa<FunctionSymbol>(sym));
       continue;
     }