diff --git a/lib/core/Handles/HandlesAnnAssign.py b/lib/core/Handles/HandlesAnnAssign.py
index c34a3b2..35b63a0 100644
--- a/lib/core/Handles/HandlesAnnAssign.py
+++ b/lib/core/Handles/HandlesAnnAssign.py
@@ -37,7 +37,7 @@ class AnnAssignHandle(BaseHandle):
             if isinstance(Value.type, ir.PointerType) and isinstance(Value.type.pointee, ir.IntType) and Value.type.pointee.width == 8:
                 if 'llvm.memcpy' not in Gen.functions:
                     memcpy_type: ir.FunctionType = ir.FunctionType(ir.VoidType(), [ir.PointerType(ir.IntType(8)), ir.PointerType(ir.IntType(8)), ir.IntType(64), ir.IntType(32), ir.IntType(1)])
-                    Gen.functions['llvm.memcpy'] = ir.Function(Gen.module, memcpy_type, name='llvm.memcpy')
+                    Gen.functions['llvm.memcpy'] = Gen._CreateOrReuseFuncDecl('llvm.memcpy', memcpy_type)
                 if isinstance(DestPtr.type.pointee, ir.IntType) and not isinstance(DestPtr.type.pointee, ir.IntType(8)):
                     DestPtr = Gen.builder.bitcast(DestPtr, ir.PointerType(ir.IntType(8)), name=f"strcpy_dst_cast_{VarName}")
                 if isinstance(Value.type.pointee, ir.IntType) and not isinstance(Value.type.pointee, ir.IntType(8)):
diff --git a/lib/core/Handles/HandlesAssign.py b/lib/core/Handles/HandlesAssign.py
index e9cdeb6..32bcd76 100644
--- a/lib/core/Handles/HandlesAssign.py
+++ b/lib/core/Handles/HandlesAssign.py
@@ -843,7 +843,7 @@ class AssignHandle(BaseHandle):
                             MemcpyFunc: ir.Function | None = Gen._find_function('llvm.memcpy.p0i8.p0i8.i64')
                             if not MemcpyFunc:
                                 MemcpyType: ir.FunctionType = ir.FunctionType(ir.VoidType(), [ir.PointerType(ir.IntType(8)), ir.PointerType(ir.IntType(8)), ir.IntType(64), ir.IntType(1)])
-                                MemcpyFunc = ir.Function(Gen.module, MemcpyType, name='llvm.memcpy.p0i8.p0i8.i64')
+                                MemcpyFunc = Gen._CreateOrReuseFuncDecl('llvm.memcpy.p0i8.p0i8.i64', MemcpyType)
                                 Gen.functions['llvm.memcpy.p0i8.p0i8.i64'] = MemcpyFunc
                             Gen.builder.call(MemcpyFunc, [VtableCopyTyped, SrcTyped, ir.Constant(ir.IntType(64), VtableSize), ir.Constant(ir.IntType(1), 0)])
                             VtableCopyGlobalAddr: ir.Value = Gen.builder.bitcast(VtableCopyGlobal, ir.PointerType(ir.IntType(8)), name=f"vtable_copy_addr")
@@ -1125,7 +1125,7 @@ class AssignHandle(BaseHandle):
                                 MemcpyFunc: ir.Function | None = Gen._find_function('llvm.memcpy.p0i8.p0i8.i64')
                                 if not MemcpyFunc:
                                     MemcpyType: ir.FunctionType = ir.FunctionType(ir.VoidType(), [ir.PointerType(ir.IntType(8)), ir.PointerType(ir.IntType(8)), ir.IntType(64), ir.IntType(1)])
-                                    MemcpyFunc = ir.Function(Gen.module, MemcpyType, name='llvm.memcpy.p0i8.p0i8.i64')
+                                    MemcpyFunc = Gen._CreateOrReuseFuncDecl('llvm.memcpy.p0i8.p0i8.i64', MemcpyType)
                                     Gen.functions['llvm.memcpy.p0i8.p0i8.i64'] = MemcpyFunc
                                 Gen.builder.call(MemcpyFunc, [VtableCopyTyped, SrcTyped, ir.Constant(ir.IntType(64), VtableSize), ir.Constant(ir.IntType(1), 0)])
                                 VtableCopyGlobalAddr: ir.Value = Gen.builder.bitcast(VtableCopyGlobal, ir.PointerType(ir.IntType(8)), name=f"vtable_copy_addr")
diff --git a/lib/core/Handles/HandlesAsyncFunctions.py b/lib/core/Handles/HandlesAsyncFunctions.py
index a72560b..2bb8415 100644
--- a/lib/core/Handles/HandlesAsyncFunctions.py
+++ b/lib/core/Handles/HandlesAsyncFunctions.py
@@ -360,7 +360,7 @@ class AsyncFunctionHandle(BaseHandle):
             if getattr(fn, 'name', None) == 'malloc':
                 return fn
         malloc_ty: ir.FunctionType = ir.FunctionType(ir.PointerType(ir.IntType(8)), [ir.IntType(64)])
-        fn: ir.Function = ir.Function(Gen.module, malloc_ty, name='malloc')
+        fn: ir.Function = Gen._CreateOrReuseFuncDecl('malloc', malloc_ty)
         Gen.functions['malloc'] = fn
         return fn
 
@@ -377,7 +377,7 @@ class AsyncFunctionHandle(BaseHandle):
         params: list[tuple[str, ir.Type]] = getattr(Gen, '_coro_param_vars', {}).get(name, [])
         param_tys: list[ir.Type] = [ty for _, ty in params]
         create_ty: ir.FunctionType = ir.FunctionType(ir.PointerType(frame_ty), param_tys)
-        create_fn: ir.Function = ir.Function(Gen.module, create_ty, name=Gen._mangle_func_name(f'create_{name}'))
+        create_fn: ir.Function = Gen._CreateOrReuseFuncDecl(Gen._mangle_func_name(f'create_{name}'), create_ty)
         self._RegisterCoroFunction(Gen, f'create_{name}', create_fn)
         create_fn.attributes.add('noredzone')
         entry: ir.Block = create_fn.append_basic_block('entry')
@@ -431,7 +431,7 @@ class AsyncFunctionHandle(BaseHandle):
 
     def _EmitResumeFunction(self, name: str, Node: ast.AsyncFunctionDef, frame_ty: ir.IdentifiedStructType, Gen: LlvmCodeGenerator) -> None:
         resume_ty: ir.FunctionType = ir.FunctionType(ir.IntType(32), [ir.PointerType(frame_ty)])
-        resume_fn: ir.Function = ir.Function(Gen.module, resume_ty, name=Gen._mangle_func_name(f'resume_{name}'))
+        resume_fn: ir.Function = Gen._CreateOrReuseFuncDecl(Gen._mangle_func_name(f'resume_{name}'), resume_ty)
         self._RegisterCoroFunction(Gen, f'resume_{name}', resume_fn)
         resume_fn.attributes.add('noredzone')
         Gen.func = resume_fn
@@ -674,7 +674,7 @@ class AsyncFunctionHandle(BaseHandle):
         fn: ir.Function | None = Gen._get_function(name)
         if fn is not None:
             return fn
-        fn = ir.Function(Gen.module, ir.FunctionType(ret_ty, args or []), name=name)
+        fn = Gen._CreateOrReuseFuncDecl(name, ir.FunctionType(ret_ty, args or []))
         Gen.functions[name] = fn
         return fn
 
@@ -682,7 +682,7 @@ class AsyncFunctionHandle(BaseHandle):
         for fn in Gen.module.global_values:
             if getattr(fn, 'name', None) == 'free':
                 return fn
-        fn = ir.Function(Gen.module, ir.FunctionType(ir.VoidType(), [ir.PointerType(ir.IntType(8))]), name='free')
+        fn = Gen._CreateOrReuseFuncDecl('free', ir.FunctionType(ir.VoidType(), [ir.PointerType(ir.IntType(8))]))
         Gen.functions['free'] = fn
         return fn
 
diff --git a/lib/core/Handles/HandlesBase.py b/lib/core/Handles/HandlesBase.py
index cf2a632..10ce8fc 100644
--- a/lib/core/Handles/HandlesBase.py
+++ b/lib/core/Handles/HandlesBase.py
@@ -1430,7 +1430,7 @@ class BaseHandle:
                 Gen.functions[name] = g_existing
                 return g_existing
             func_type = _ir.FunctionType(ret_type, param_types, var_arg=is_variadic)
-            func_decl = _ir.Function(Gen.module, func_type, name=name)
+            func_decl = Gen._CreateOrReuseFuncDecl(name, func_type)
             Gen.functions[name] = func_decl
         else:
             existing = Gen.functions[name]
@@ -1467,7 +1467,7 @@ class BaseHandle:
             if g_ex_decl is not None:
                 func_decl = g_ex_decl
             else:
-                func_decl = _ir.Function(Gen.module, stub_func_type, name=decl_name)
+                func_decl = Gen._CreateOrReuseFuncDecl(decl_name, stub_func_type)
             Gen.functions[decl_name] = func_decl
         if alias and alias != decl_name:
             if not check_existing or alias not in Gen.functions:
diff --git a/lib/core/Handles/HandlesExpr.py b/lib/core/Handles/HandlesExpr.py
index 7106996..d58044d 100644
--- a/lib/core/Handles/HandlesExpr.py
+++ b/lib/core/Handles/HandlesExpr.py
@@ -164,9 +164,12 @@ class ExprHandle(BaseHandle):
         if not malloc_fn:
             try:
                 malloc_fn_type: ir.FunctionType = ir.FunctionType(ir.PointerType(ir.IntType(8)), [ir.IntType(64)])
-                malloc_fn = ir.Function(Gen.module, malloc_fn_type, name='malloc')
+                malloc_fn = Gen._CreateOrReuseFuncDecl('malloc', malloc_fn_type)
                 Gen.functions['malloc'] = malloc_fn
-            except Exception:  # 回退：malloc 函数创建失败时返回 null
+            except Exception as _e:  # 回退：malloc 函数创建失败时返回 null
+                from lib.core.LLVMCG.FuncGen import FailFastError as _FFE
+                if isinstance(_e, _FFE):
+                    raise
                 return ir.Constant(ir.IntType(8).as_pointer(), None)
 
         alloc_ptr: Any = Gen.builder.call(malloc_fn, [ir.Constant(malloc_arg_type, alloc_size)])
diff --git a/lib/core/Handles/HandlesExprBuiltin.py b/lib/core/Handles/HandlesExprBuiltin.py
index 0615343..cac113a 100644
--- a/lib/core/Handles/HandlesExprBuiltin.py
+++ b/lib/core/Handles/HandlesExprBuiltin.py
@@ -730,9 +730,12 @@ class ExprBuiltinHandle(BaseHandle):
                         strlen_func = existing
                 if not strlen_func:
                     try:
-                        strlen_func = ir.Function(Gen.module, correct_strlen_type, name='strlen')
+                        strlen_func = Gen._CreateOrReuseFuncDecl('strlen', correct_strlen_type)
                         Gen.functions['strlen'] = strlen_func
                     except Exception as _e:
+                        from lib.core.LLVMCG.FuncGen import FailFastError as _FFE
+                        if isinstance(_e, _FFE):
+                            raise
                         if _config_mode == "strict":
                             self.Trans.LogWarning(f"异常被忽略: {_e}")
                 if strlen_func:
@@ -1048,7 +1051,7 @@ class ExprBuiltinHandle(BaseHandle):
         Gen: LlvmGeneratorMixin = self.Trans.LlvmGen
         if 'llvm.memcpy' not in Gen.functions:
             memcpy_type: ir.FunctionType = ir.FunctionType(ir.VoidType(), [ir.PointerType(ir.IntType(8)), ir.PointerType(ir.IntType(8)), ir.IntType(64), ir.IntType(1)])
-            Gen.functions['llvm.memcpy'] = ir.Function(Gen.module, memcpy_type, name='llvm.memcpy')
+            Gen.functions['llvm.memcpy'] = Gen._CreateOrReuseFuncDecl('llvm.memcpy', memcpy_type)
         if len(args) >= 3:
             dst: ir.Value | None = self.HandleExprLlvm(args[0])
             src: ir.Value | None = self.HandleExprLlvm(args[1])
diff --git a/lib/core/Handles/HandlesExprCall.py b/lib/core/Handles/HandlesExprCall.py
index 1652101..5216603 100644
--- a/lib/core/Handles/HandlesExprCall.py
+++ b/lib/core/Handles/HandlesExprCall.py
@@ -1714,13 +1714,13 @@ class ExprCallHandle(BaseHandle):
                         try:
                             func = Gen.module.declare_intrinsic(func_name, [a.type for a in call_args])
                         except Exception:
-                            func = ir.Function(Gen.module, func_type, name=func_name)
+                            func = Gen._CreateOrReuseFuncDecl(func_name, func_type)
                 else:
                     existing = Gen.module.globals.get(func_name)
                     if existing:
                         func = existing
                     else:
-                        func = ir.Function(Gen.module, func_type, name=func_name)
+                        func = Gen._CreateOrReuseFuncDecl(func_name, func_type)
                 result = Gen.builder.call(func, call_args, name="llvmir_result")
                 if output_targets:
                     return self._StoreLLVMIROutputs(Gen, result, output_targets)
@@ -1984,7 +1984,7 @@ class ExprCallHandle(BaseHandle):
                     Gen.functions[func_name] = g_ex_w32
                 else:
                     func_type = ir.FunctionType(ret_type, param_types)
-                    func_decl = ir.Function(Gen.module, func_type, name=func_name)
+                    func_decl = Gen._CreateOrReuseFuncDecl(func_name, func_type)
                     func_decl.linkage = 'external'
                     Gen.functions[func_name] = func_decl
             call_args = []
@@ -4158,9 +4158,12 @@ class ExprCallHandle(BaseHandle):
                         strlen_func = existing
                 if not strlen_func:
                     try:
-                        strlen_func = ir.Function(Gen.module, correct_strlen_type, name='strlen')
+                        strlen_func = Gen._CreateOrReuseFuncDecl('strlen', correct_strlen_type)
                         Gen.functions['strlen'] = strlen_func
                     except Exception as _e:
+                        from lib.core.LLVMCG.FuncGen import FailFastError as _FFE
+                        if isinstance(_e, _FFE):
+                            raise
                         if _config_mode == "strict":
                             self.Trans.LogWarning(f"异常被忽略: {_e}")
                 if strlen_func:
@@ -4783,7 +4786,7 @@ class ExprCallHandle(BaseHandle):
         Gen = self.Trans.LlvmGen
         if 'llvm.memcpy' not in Gen.functions:
             memcpy_type = ir.FunctionType(ir.VoidType(), [ir.PointerType(ir.IntType(8)), ir.PointerType(ir.IntType(8)), ir.IntType(64), ir.IntType(1)])
-            Gen.functions['llvm.memcpy'] = ir.Function(Gen.module, memcpy_type, name='llvm.memcpy')
+            Gen.functions['llvm.memcpy'] = Gen._CreateOrReuseFuncDecl('llvm.memcpy', memcpy_type)
         if len(args) >= 3:
             dst = self.HandleExprLlvm(args[0])
             src = self.HandleExprLlvm(args[1])
diff --git a/lib/core/Handles/HandlesExprLambda.py b/lib/core/Handles/HandlesExprLambda.py
index 7078ad6..cb1e883 100644
--- a/lib/core/Handles/HandlesExprLambda.py
+++ b/lib/core/Handles/HandlesExprLambda.py
@@ -29,7 +29,7 @@ class ExprLambdaHandle(BaseHandle):
             for arg in Node.args.args:
                 param_types.append(ir.IntType(32))
         fn_type: ir.FunctionType = ir.FunctionType(ret_type, param_types)
-        fn: ir.Function = ir.Function(Gen.module, fn_type, name=fn_name)
+        fn: ir.Function = Gen._CreateOrReuseFuncDecl(fn_name, fn_type)
         Gen.functions[fn_name] = fn
         entry_block: ir.Block = fn.append_basic_block(name=f"{fn_name}_entry")
         prev_builder: Any = Gen.builder
diff --git a/lib/core/Handles/HandlesFunctions.py b/lib/core/Handles/HandlesFunctions.py
index 79352de..36982b4 100644
--- a/lib/core/Handles/HandlesFunctions.py
+++ b/lib/core/Handles/HandlesFunctions.py
@@ -1319,7 +1319,10 @@ class FunctionHandle(BaseHandle):
         old_func: Any = Gen.functions.get(MangledName)
         if old_func is None:
             try:
-                return ir.Function(Gen.module, NewFuncType, name=MangledName)
+                # 走唯一幂等入口：名字可能已存在于 module.globals 但未登记进 Gen.functions
+                # （别的路径先建过声明）——直接 ir.Function 必抛裸 DuplicatedNameError，
+                # 入口则同名同类型复用、异类型带两侧签名 fail-fast。
+                return Gen._CreateOrReuseFuncDecl(MangledName, NewFuncType)
             except Exception as _e:  # 回退：函数已存在时返回旧函数
                 from lib.core.LLVMCG.FuncGen import FailFastError as _FFE
                 if isinstance(_e, _FFE):
diff --git a/lib/core/Handles/HandlesImports.py b/lib/core/Handles/HandlesImports.py
index 5642d6a..404c13b 100644
--- a/lib/core/Handles/HandlesImports.py
+++ b/lib/core/Handles/HandlesImports.py
@@ -3718,7 +3718,7 @@ class ImportHandle(BaseHandle):
                             if g_ex_stub is not None:
                                 func = g_ex_stub
                             else:
-                                func = ir.Function(Gen.module, func_type, name=func_name)
+                                func = Gen._CreateOrReuseFuncDecl(func_name, func_type)
                             Gen.functions[func_name] = func
                             if '.' in func_name:
                                 short_fn = func_name.split('.', 1)[1]
diff --git a/lib/core/LLVMCG/BaseGen.py b/lib/core/LLVMCG/BaseGen.py
index 63ea982..5178250 100644
--- a/lib/core/LLVMCG/BaseGen.py
+++ b/lib/core/LLVMCG/BaseGen.py
@@ -1603,7 +1603,7 @@ class BaseGenMixin:
                     f'--hotspot-sites: 外部函数 {name} 已存在但签名不一致'
                     f'（期望 {ftype}，实际 {existing.ftype}）')
             return existing
-        return ir.Function(self.module, ftype, name=name)
+        return self._CreateOrReuseFuncDecl(name, ftype)
 
     def _InstallHotspotTruncate(
         self,
@@ -1970,9 +1970,9 @@ class BaseGenMixin:
         fprintf: ir.Function = self._DeclareExternalFunc(
             'fprintf', ir.FunctionType(i32, [i8p, i8p], var_arg=True))
         fclose: ir.Function = self._DeclareExternalFunc('fclose', ir.FunctionType(i32, [i8p]))
-        dump_fn: ir.Function = ir.Function(
-            self.module, ir.FunctionType(ir.VoidType(), []),
-            name=self._UniqueGlobalName('__fhs_dump_sites'))
+        dump_fn: ir.Function = self._CreateOrReuseFuncDecl(
+            self._UniqueGlobalName('__fhs_dump_sites'),
+            ir.FunctionType(ir.VoidType(), []))
         dump_fn.linkage = 'internal'
         b: ir.IRBuilder = ir.IRBuilder(dump_fn.append_basic_block(name='entry'))
         b.position_at_start(dump_fn.entry_basic_block)
@@ -2156,9 +2156,9 @@ class BaseGenMixin:
         fprintf: ir.Function = self._DeclareExternalFunc(
             'fprintf', ir.FunctionType(i32, [i8p, i8p], var_arg=True))
         fclose: ir.Function = self._DeclareExternalFunc('fclose', ir.FunctionType(i32, [i8p]))
-        dump_fn: ir.Function = ir.Function(
-            self.module, ir.FunctionType(ir.VoidType(), []),
-            name=self._UniqueGlobalName('__fhs_dump_time'))
+        dump_fn: ir.Function = self._CreateOrReuseFuncDecl(
+            self._UniqueGlobalName('__fhs_dump_time'),
+            ir.FunctionType(ir.VoidType(), []))
         dump_fn.linkage = 'internal'
         b: ir.IRBuilder = ir.IRBuilder(dump_fn.append_basic_block(name='entry'))
         b.position_at_start(dump_fn.entry_basic_block)
@@ -2310,9 +2310,9 @@ class BaseGenMixin:
             self.module, i32, name=self._UniqueGlobalName('__fhs_dumped'))
         guard.linkage = 'internal'
         guard.initializer = ir.Constant(i32, 0)
-        dump_all: ir.Function = ir.Function(
-            self.module, ir.FunctionType(ir.VoidType(), []),
-            name=self._UniqueGlobalName('__fhs_dump_all'))
+        dump_all: ir.Function = self._CreateOrReuseFuncDecl(
+            self._UniqueGlobalName('__fhs_dump_all'),
+            ir.FunctionType(ir.VoidType(), []))
         dump_all.linkage = 'internal'
         b: ir.IRBuilder = ir.IRBuilder(dump_all.append_basic_block(name='entry'))
         do_bb: ir.Block = dump_all.append_basic_block(name='fhs_dump_do')
@@ -2327,9 +2327,9 @@ class BaseGenMixin:
         b.branch(done_bb)
         b.position_at_end(done_bb)
         b.ret_void()
-        ctl_handler: ir.Function = ir.Function(
-            self.module, ir.FunctionType(i32, [i32]),
-            name=self._UniqueGlobalName('__fhs_ctl_handler'))
+        ctl_handler: ir.Function = self._CreateOrReuseFuncDecl(
+            self._UniqueGlobalName('__fhs_ctl_handler'),
+            ir.FunctionType(i32, [i32]))
         ctl_handler.linkage = 'internal'
         cb: ir.IRBuilder = ir.IRBuilder(ctl_handler.append_basic_block(name='entry'))
         cb.call(dump_all, [])
@@ -2380,9 +2380,9 @@ class BaseGenMixin:
         i32: ir.IntType = ir.IntType(32)
         i8p: ir.PointerType = ir.PointerType(ir.IntType(8))
         void_fnptr: ir.PointerType = ir.PointerType(ir.FunctionType(ir.VoidType(), []))
-        ctor: ir.Function = ir.Function(
-            self.module, ir.FunctionType(ir.VoidType(), []),
-            name=self._UniqueGlobalName('__fhs_sites_ctor'))
+        ctor: ir.Function = self._CreateOrReuseFuncDecl(
+            self._UniqueGlobalName('__fhs_sites_ctor'),
+            ir.FunctionType(ir.VoidType(), []))
         ctor.linkage = 'internal'
         cb: ir.IRBuilder = ir.IRBuilder(ctor.append_basic_block(name='entry'))
         self._EmitHotspotDumpRegistration(cb, ctl_handler, dump_all)
@@ -2429,9 +2429,9 @@ class BaseGenMixin:
         i32: ir.IntType = ir.IntType(32)
         i8p: ir.PointerType = ir.PointerType(ir.IntType(8))
         void_fnptr: ir.PointerType = ir.PointerType(ir.FunctionType(ir.VoidType(), []))
-        ctor: ir.Function = ir.Function(
-            self.module, ir.FunctionType(ir.VoidType(), []),
-            name=self._UniqueGlobalName('__traceback_install_ctor'))
+        ctor: ir.Function = self._CreateOrReuseFuncDecl(
+            self._UniqueGlobalName('__traceback_install_ctor'),
+            ir.FunctionType(ir.VoidType(), []))
         ctor.linkage = 'internal'
         cb: ir.IRBuilder = ir.IRBuilder(ctor.append_basic_block(name='entry'))
         cb.call(install_fn, [])  # Install() 无参；返回值（int）有意忽略
diff --git a/lib/core/LLVMCG/ExprGen.py b/lib/core/LLVMCG/ExprGen.py
index d6c80b0..5b36048 100644
--- a/lib/core/LLVMCG/ExprGen.py
+++ b/lib/core/LLVMCG/ExprGen.py
@@ -237,7 +237,7 @@ class ExprGenMixin:
             powf: ir.Function | None = self.module.globals.get('llvm.pow.f64')
             if not powf:
                 fnty: ir.FunctionType = ir.FunctionType(ir.DoubleType(), [ir.DoubleType(), ir.DoubleType()])
-                powf = ir.Function(self.module, fnty, name='llvm.pow.f64')
+                powf = self._CreateOrReuseFuncDecl('llvm.pow.f64', fnty)
             if lf.type != ir.DoubleType():
                 lf = self.builder.fpext(lf, ir.DoubleType(), name="ext_f64")
             if rf.type != ir.DoubleType():
diff --git a/lib/core/LLVMCG/VaArg.py b/lib/core/LLVMCG/VaArg.py
index b349639..6dd4a48 100644
--- a/lib/core/LLVMCG/VaArg.py
+++ b/lib/core/LLVMCG/VaArg.py
@@ -9,7 +9,7 @@ class VaArgMixin:
         if 'llvm.va_start' in self.functions:
             return self.functions['llvm.va_start']
         ftype: ir.FunctionType = ir.FunctionType(ir.VoidType(), [ir.IntType(8).as_pointer()])
-        func: ir.Function = ir.Function(self.module, ftype, name='llvm.va_start')
+        func: ir.Function = self._CreateOrReuseFuncDecl('llvm.va_start', ftype)
         self.functions['llvm.va_start'] = func
         return func
 
@@ -17,7 +17,7 @@ class VaArgMixin:
         if 'llvm.va_end' in self.functions:
             return self.functions['llvm.va_end']
         ftype: ir.FunctionType = ir.FunctionType(ir.VoidType(), [ir.IntType(8).as_pointer()])
-        func: ir.Function = ir.Function(self.module, ftype, name='llvm.va_end')
+        func: ir.Function = self._CreateOrReuseFuncDecl('llvm.va_end', ftype)
         self.functions['llvm.va_end'] = func
         return func