Fix s2wasm handling of aliased functions

This fixes 2 bugs in s2wasm:

* Handle address-taken aliases (i.e. when they appear in relocations), by looking up and subsituting the address of the aliasee.
* Skip whitespace at the top of the scan() loop instead of requiring it to match. When there are multiple alias declarations in a row, the match("FUNCTION") at the end of an alias delcaration consumes the whitespace at the beginning of the next line, causing it to fail to match the tab character specified in the match pattern at the top of  the loop.

3 files changed, 15 insertions, 6 deletions

diff --git a/src/s2wasm.h b/src/s2wasm.h
index c85a214a1..c2e8c77a0 100644
--- a/src/s2wasm.h
+++ b/src/s2wasm.h
@@ -405,9 +405,10 @@ class S2WasmBuilder {
 
   void scan() {
     while (*s) {
-      s = strstr(s, "\n	.type	");
+      skipWhitespace();
+      s = strstr(s, ".type");
       if (!s) break;
-      mustMatch("\n	.type	");
+      mustMatch(".type");
       Name name = getCommaSeparated();
       skipComma();
       if (!match("@function")) continue;
@@ -1282,6 +1283,8 @@ class S2WasmBuilder {
         if (debug) std::cerr << "  ==> " << *(relocation.data) << '\n';
       } else {
         // must be a function address
+        auto aliased = aliasedFunctions.find(name);
+        if (aliased != aliasedFunctions.end()) name = aliased->second;
         if (!wasm.checkFunction(name)) {
           std::cerr << "Unknown symbol: " << name << '\n';
           if (!ignoreUnknownSymbols) abort();
diff --git a/test/dot_s/alias.s b/test/dot_s/alias.s
index a29470b2f..85a89a16f 100644
--- a/test/dot_s/alias.s
+++ b/test/dot_s/alias.s
@@ -16,9 +16,11 @@ __exit:                           # @__exit
 	.globl	__needs_exit
 	.type	__needs_exit,@function
 __needs_exit:              # @__needs_exit
+        .result i32
 # BB#0:                                 # %entry
 	call    	__exit_needed@FUNCTION
-	return
+        i32.const       $push0=, __exit_needed@FUNCTION
+	return  $pop0
 	.endfunc
 .Lfunc_end1:
 	.size	__needs_exit, .Lfunc_end1-__needs_exit
diff --git a/test/dot_s/alias.wast b/test/dot_s/alias.wast
index a6c9994b9..c9c64117b 100644
--- a/test/dot_s/alias.wast
+++ b/test/dot_s/alias.wast
@@ -1,15 +1,19 @@
 (module
   (memory 1)
   (export "memory" memory)
+  (type $FUNCSIG$v (func))
   (export "__exit" $__exit)
   (export "__needs_exit" $__needs_exit)
-  (func $__exit
+  (table $__exit)
+  (func $__exit (type $FUNCSIG$v)
     (local $$0 i32)
     (return)
   )
-  (func $__needs_exit
+  (func $__needs_exit (result i32)
     (call $__exit)
-    (return)
+    (return
+      (i32.const 0)
+    )
   )
 )
 ;; METADATA: { "asmConsts": {},"staticBump": 12, "initializers": [] }