From c2bd94fb7a36bb9b09242e013b50b0ad58bc0f84 Mon Sep 17 00:00:00 2001
From: Owanesh <24321561+Owanesh@users.noreply.github.com>
Date: Wed, 1 Apr 2026 18:22:07 +0200
Subject: [PATCH] fix(parser): handle single-line functions in parseWast

Empty-body functions like (func $f (type $t0) (param $p0 i32))` have balanced brackets on a single line, so `func_bracketNum` drops to 0 immediately. The parser never finalized them, leaking their header into the next function's header list. `opaque_predicate_insertion` then appended `(local $wadelocal i32)` to the wrong line, producing invalid .wat that breaks wat2wasm
---
 strategies/code_perturbation.py |  4 ++--
 wasmParser/parser.py            | 23 ++++++++++++++++++++---
 2 files changed, 22 insertions(+), 5 deletions(-)

diff --git a/strategies/code_perturbation.py b/strategies/code_perturbation.py
index c29ac3f..a2cfd5c 100644
--- a/strategies/code_perturbation.py
+++ b/strategies/code_perturbation.py
@@ -1314,9 +1314,9 @@ def opaque_predicate_insertion(parsedSection, alpha, beta, ratio):
     for f in functions:
         # print(f)
         function = parsedSection['Function'][f]
-        if function.body == None:
+        if function.body is None or len(function.body) == 0:
             continue
-        
+
         body = function.body
 
         offset_list = list()
diff --git a/wasmParser/parser.py b/wasmParser/parser.py
index 458d467..fa1b0ac 100755
--- a/wasmParser/parser.py
+++ b/wasmParser/parser.py
@@ -264,10 +264,27 @@ def parseWast(origin_wast):
             
             funcHeaderArea = True ##function header line이 여러개인 경우, payload와 분류하기 위해
             funcHeaderLine.append([line, ''])
-            
+
             parsedSection["Function"][funcID] = ss.FUNCTION(type=funcType)
-        
-            
+
+            # Handle single-line functions where brackets balance on one line
+            # e.g. (func $f44 (type $t0) (param $p0 i32))
+            if func_bracketNum == 0:
+                funcHeaderStr = ''.join([h[0].strip() for h in funcHeaderLine])
+                params = parse_param_local_blocks(funcHeaderStr, RE_PARAM)
+                locals_ = parse_param_local_blocks(funcHeaderStr, RE_LOCAL)
+                has_result = re.search(RE_RESULT, funcHeaderStr)
+                result = has_result.group(1) if has_result is not None else None
+
+                parsedSection["Function"][funcID].param = params
+                parsedSection["Function"][funcID].result = result
+                parsedSection["Function"][funcID].local = locals_
+                parsedSection["Function"][funcID].header = funcHeaderLine
+                parsedSection["Function"][funcID].body = []
+
+                funcHeaderArea = False
+                funcHeaderLine = list()
+
         # print(whichSection)
         if 1 not in whichSection and (funcHeaderArea==True or funcBodyArea==True):