perf(api): allow to use an arena for return values

2025-09-07 03:48:18 +00:00 · 2022-08-23 09:33:08 +02:00
parent baaaa1f2b3
commit c0d6052654
36 changed files with 584 additions and 497 deletions
--- a/scripts/gen_vimdoc.py
+++ b/scripts/gen_vimdoc.py
@@ -801,7 +801,7 @@ def extract_from_xml(filename, target, width, fmt_vimhelp):

        prefix = '%s(' % name
        suffix = '%s)' % ', '.join('{%s}' % a[1] for a in params
-                                   if a[0] not in ('void', 'Error'))
+                                   if a[0] not in ('void', 'Error', 'Arena'))

        if not fmt_vimhelp:
            c_decl = '%s %s(%s);' % (return_type, name, ', '.join(c_args))
--- a/src/nvim/api/buffer.c
+++ b/src/nvim/api/buffer.c
@@ -1021,7 +1021,7 @@ void nvim_buf_del_var(Buffer buffer, String name, Error *err)
 /// @param buffer     Buffer handle, or 0 for current buffer
 /// @param[out] err   Error details, if any
 /// @return Buffer name
-String nvim_buf_get_name(Buffer buffer, Error *err)
+String nvim_buf_get_name(Buffer buffer, Arena *arena, Error *err)
  FUNC_API_SINCE(1)
 {
  String rv = STRING_INIT;
@@ -1031,7 +1031,7 @@ String nvim_buf_get_name(Buffer buffer, Error *err)
    return rv;
  }

-  return cstr_to_string((char *)buf->b_ffname);
+  return cstr_as_string((char *)buf->b_ffname);
 }

 /// Sets the full file name for a buffer
--- a/src/nvim/api/private/dispatch.h
+++ b/src/nvim/api/private/dispatch.h
@@ -5,18 +5,23 @@

 typedef Object (*ApiDispatchWrapper)(uint64_t channel_id,
                                     Array args,
+                                     Arena *arena,
                                     Error *error);

 /// The rpc_method_handlers table, used in msgpack_rpc_dispatch(), stores
 /// functions of this type.
-typedef struct {
+struct MsgpackRpcRequestHandler {
  const char *name;
  ApiDispatchWrapper fn;
  bool fast;  // Function is safe to be executed immediately while running the
              // uv loop (the loop is run very frequently due to breakcheck).
              // If "fast" is false, the function is deferred, i e the call will
              // be put in the event queue, for safe handling later.
-} MsgpackRpcRequestHandler;
+  bool arena_return;  // return value is allocated in the arena (or statically)
+                      // and should not be freed as such.
+};
+
+extern const MsgpackRpcRequestHandler method_handlers[];

 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # include "api/private/dispatch.h.generated.h"
--- a/src/nvim/api/vim.c
+++ b/src/nvim/api/vim.c
@@ -1629,11 +1629,11 @@ Array nvim_list_chans(void)
 /// an error, it is a three-element array with the zero-based index of the call
 /// which resulted in an error, the error type and the error message. If an
 /// error occurred, the values from all preceding calls will still be returned.
-Array nvim_call_atomic(uint64_t channel_id, Array calls, Error *err)
+Array nvim_call_atomic(uint64_t channel_id, Array calls, Arena *arena, Error *err)
  FUNC_API_SINCE(1) FUNC_API_REMOTE_ONLY
 {
-  Array rv = ARRAY_DICT_INIT;
-  Array results = ARRAY_DICT_INIT;
+  Array rv = arena_array(arena, 2);
+  Array results = arena_array(arena, calls.size);
  Error nested_error = ERROR_INIT;

  size_t i;  // also used for freeing the variables
@@ -1676,29 +1676,32 @@ Array nvim_call_atomic(uint64_t channel_id, Array calls, Error *err)
    if (ERROR_SET(&nested_error)) {
      break;
    }
-    Object result = handler.fn(channel_id, args, &nested_error);
+
+    Object result = handler.fn(channel_id, args, arena, &nested_error);
    if (ERROR_SET(&nested_error)) {
      // error handled after loop
      break;
    }
+    if (!handler.arena_return && result.type != kObjectTypeNil) {
+      // TODO: fix to not leak memory as fuck
+    }

-    ADD(results, result);
+    ADD_C(results, result);
  }

-  ADD(rv, ARRAY_OBJ(results));
+  ADD_C(rv, ARRAY_OBJ(results));
  if (ERROR_SET(&nested_error)) {
-    Array errval = ARRAY_DICT_INIT;
-    ADD(errval, INTEGER_OBJ((Integer)i));
-    ADD(errval, INTEGER_OBJ(nested_error.type));
-    ADD(errval, STRING_OBJ(cstr_to_string(nested_error.msg)));
-    ADD(rv, ARRAY_OBJ(errval));
+    Array errval = arena_array(arena, 3);
+    ADD_C(errval, INTEGER_OBJ((Integer)i));
+    ADD_C(errval, INTEGER_OBJ(nested_error.type));
+    ADD_C(errval, STRING_OBJ(cstr_to_string(nested_error.msg))); // TODO
+    ADD_C(rv, ARRAY_OBJ(errval));
  } else {
-    ADD(rv, NIL);
+    ADD_C(rv, NIL);
  }
  goto theend;

 validation_error:
-  api_free_array(results);
 theend:
  api_clear_error(&nested_error);
  return rv;
@@ -1803,6 +1806,7 @@ Dictionary nvim__stats(void)
  PUT(rv, "log_skip", INTEGER_OBJ(g_stats.log_skip));
  PUT(rv, "lua_refcount", INTEGER_OBJ(nlua_get_global_ref_count()));
  PUT(rv, "redraw", INTEGER_OBJ(g_stats.redraw));
+  PUT(rv, "arena_alloc_count", INTEGER_OBJ((Integer)arena_alloc_count));
  return rv;
 }

--- a/src/nvim/arglist.c
+++ b/src/nvim/arglist.c
@@ -1074,7 +1074,7 @@ char *arg_all(void)
 }

 /// "argc([window id])" function
-void f_argc(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_argc(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  if (argvars[0].v_type == VAR_UNKNOWN) {
    // use the current window
@@ -1095,13 +1095,13 @@ void f_argc(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 }

 /// "argidx()" function
-void f_argidx(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_argidx(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  rettv->vval.v_number = curwin->w_arg_idx;
 }

 /// "arglistid()" function
-void f_arglistid(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_arglistid(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  rettv->vval.v_number = -1;
  win_T *wp = find_tabwin(&argvars[0], &argvars[1]);
@@ -1123,7 +1123,7 @@ static void get_arglist_as_rettv(aentry_T *arglist, int argcount, typval_T *rett
 }

 /// "argv(nr)" function
-void f_argv(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_argv(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  aentry_T *arglist = NULL;
  int argcount = -1;
--- a/src/nvim/cmdexpand.c
+++ b/src/nvim/cmdexpand.c
@@ -2751,7 +2751,7 @@ void wildmenu_cleanup(CmdlineInfo *cclp)
 }

 /// "getcompletion()" function
-void f_getcompletion(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_getcompletion(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  char_u *pat;
  expand_T xpc;
--- a/src/nvim/cmdhist.c
+++ b/src/nvim/cmdhist.c
@@ -494,7 +494,7 @@ static int del_history_idx(int histype, int idx)
 }

 /// "histadd()" function
-void f_histadd(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_histadd(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  HistoryType histype;

@@ -517,7 +517,7 @@ void f_histadd(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 }

 /// "histdel()" function
-void f_histdel(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_histdel(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  int n;
  const char *const str = tv_get_string_chk(&argvars[0]);  // NULL on type error
@@ -540,7 +540,7 @@ void f_histdel(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 }

 /// "histget()" function
-void f_histget(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_histget(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  HistoryType type;
  int idx;
@@ -562,7 +562,7 @@ void f_histget(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 }

 /// "histnr()" function
-void f_histnr(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_histnr(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  const char *const histname = tv_get_string_chk(&argvars[0]);
  HistoryType i = histname == NULL
--- a/src/nvim/digraph.c
+++ b/src/nvim/digraph.c
@@ -1917,7 +1917,7 @@ static bool digraph_set_common(const typval_T *argchars, const typval_T *argdigr
 }

 /// "digraph_get()" function
-void f_digraph_get(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_digraph_get(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  rettv->v_type = VAR_STRING;
  rettv->vval.v_string = NULL;  // Return empty string for failure
@@ -1938,7 +1938,7 @@ void f_digraph_get(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 }

 /// "digraph_getlist()" function
-void f_digraph_getlist(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_digraph_getlist(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  bool flag_list_all;

@@ -1957,7 +1957,7 @@ void f_digraph_getlist(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 }

 /// "digraph_set()" function
-void f_digraph_set(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_digraph_set(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  rettv->v_type = VAR_BOOL;
  rettv->vval.v_bool = kBoolVarFalse;
@@ -1970,7 +1970,7 @@ void f_digraph_set(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 }

 /// "digraph_setlist()" function
-void f_digraph_setlist(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_digraph_setlist(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  rettv->v_type = VAR_BOOL;
  rettv->vval.v_bool = kBoolVarFalse;
--- a/src/nvim/eval.c
+++ b/src/nvim/eval.c
@@ -4968,7 +4968,7 @@ theend:
  return retval;
 }

-void common_function(typval_T *argvars, typval_T *rettv, bool is_funcref, FunPtr fptr)
+void common_function(typval_T *argvars, typval_T *rettv, bool is_funcref)
 {
  char *s;
  char *name;
--- a/src/nvim/eval.lua
+++ b/src/nvim/eval.lua
@@ -23,7 +23,7 @@ end
 return {
  funcs={
    abs={args=1, base=1},
-    acos={args=1, base=1, func="float_op_wrapper", data="&acos"},  -- WJMc
+    acos={args=1, base=1, float_func="acos"},  -- WJMc
    add={args=2, base=1},
    ['and']={args=2, base=1},
    api_info={},
@@ -33,7 +33,7 @@ return {
    argidx={},
    arglistid={args={0, 2}},
    argv={args={0, 2}},
-    asin={args=1, base=1, func="float_op_wrapper", data="&asin"},  -- WJMc
+    asin={args=1, base=1, float_func="asin"},  -- WJMc
    assert_beeps={args=1, base=1},
    assert_equal={args={2, 3}, base=2},
    assert_equalfile={args={2, 3}, base=1},
@@ -47,7 +47,7 @@ return {
    assert_notmatch={args={2, 3}, base=2},
    assert_report={args=1, base=1},
    assert_true={args={1, 2}, base=1},
-    atan={args=1, base=1, func="float_op_wrapper", data="&atan"},
+    atan={args=1, base=1, float_func="atan"},
    atan2={args=2, base=1},
    browse={args=4},
    browsedir={args=2},
@@ -67,7 +67,7 @@ return {
    byteidx={args=2, base=1},
    byteidxcomp={args=2, base=1},
    call={args={2, 3}, base=1},
-    ceil={args=1, base=1, func="float_op_wrapper", data="&ceil"},
+    ceil={args=1, base=1, float_func="ceil"},
    changenr={},
    chanclose={args={1, 2}},
    chansend={args=2},
@@ -85,8 +85,8 @@ return {
    complete_info={args={0, 1}, base=1},
    confirm={args={1, 4}, base=1},
    copy={args=1, base=1},
-    cos={args=1, base=1, func="float_op_wrapper", data="&cos"},
-    cosh={args=1, base=1, func="float_op_wrapper", data="&cosh"},
+    cos={args=1, base=1, float_func="cos"},
+    cosh={args=1, base=1, float_func="cosh"},
    count={args={2, 4}, base=1},
    cscope_connection={args={0, 3}},
    ctxget={args={0, 1}},
@@ -117,7 +117,7 @@ return {
    execute={args={1, 2}, base=1},
    exepath={args=1, base=1},
    exists={args=1, base=1},
-    exp={args=1, base=1, func="float_op_wrapper", data="&exp"},
+    exp={args=1, base=1, float_func="exp"},
    expand={args={1, 3}, base=1},
    expandcmd={args=1, base=1},
    extend={args={2, 3}, base=1},
@@ -130,7 +130,7 @@ return {
    findfile={args={1, 3}, base=1},
    flatten={args={1, 2}, base=1},
    float2nr={args=1, base=1},
-    floor={args=1, base=1, func="float_op_wrapper", data="&floor"},
+    floor={args=1, base=1, float_func="floor"},
    fmod={args=2, base=1},
    fnameescape={args=1, base=1},
    fnamemodify={args=2, base=1},
@@ -245,8 +245,8 @@ return {
    lispindent={args=1, base=1},
    list2str={args={1, 2}, base=1},
    localtime={},
-    log={args=1, base=1, func="float_op_wrapper", data="&log"},
-    log10={args=1, base=1, func="float_op_wrapper", data="&log10"},
+    log={args=1, base=1, float_func="log"},
+    log10={args=1, base=1, float_func="log10"},
    luaeval={args={1, 2}, base=1},
    map={args=2, base=1},
    maparg={args={1, 4}, base=1},
@@ -304,7 +304,7 @@ return {
    ['repeat']={args=2, base=1},
    resolve={args=1, base=1},
    reverse={args=1, base=1},
-    round={args=1, base=1, func="float_op_wrapper", data="&round"},
+    round={args=1, base=1, float_func="round"},
    rpcnotify={args=varargs(2)},
    rpcrequest={args=varargs(2)},
    rpcstart={args={1, 2}},
@@ -358,8 +358,8 @@ return {
    sign_unplace={args={1, 2}, base=1},
    sign_unplacelist={args=1, base=1},
    simplify={args=1, base=1},
-    sin={args=1, base=1, func="float_op_wrapper", data="&sin"},
-    sinh={args=1, base=1, func="float_op_wrapper", data="&sinh"},
+    sin={args=1, base=1, float_func="sin"},
+    sinh={args=1, base=1, float_func="sinh"},
    sockconnect={args={2,3}},
    sort={args={1, 3}, base=1},
    soundfold={args=1, base=1},
@@ -367,7 +367,7 @@ return {
    spellbadword={args={0, 1}, base=1},
    spellsuggest={args={1, 3}, base=1},
    split={args={1, 3}, base=1},
-    sqrt={args=1, base=1, func="float_op_wrapper", data="&sqrt"},
+    sqrt={args=1, base=1, float_func="sqrt"},
    srand={args={0, 1}, base=1},
    stdpath={args=1},
    str2float={args=1, base=1},
@@ -402,8 +402,8 @@ return {
    tabpagewinnr={args={1, 2}, base=1},
    tagfiles={},
    taglist={args={1, 2}, base=1},
-    tan={args=1, base=1, func="float_op_wrapper", data="&tan"},
-    tanh={args=1, base=1, func="float_op_wrapper", data="&tanh"},
+    tan={args=1, base=1, float_func="tan"},
+    tanh={args=1, base=1, float_func="tanh"},
    tempname={},
    termopen={args={1, 2}},
    test_garbagecollect_now={},
@@ -417,7 +417,7 @@ return {
    toupper={args=1, base=1},
    tr={args=3, base=1},
    trim={args={1, 3}, base=1},
-    trunc={args=1, base=1, func="float_op_wrapper", data="&trunc"},
+    trunc={args=1, base=1, float_func="trunc"},
    type={args=1, base=1},
    undofile={args=1, base=1},
    undotree={},
--- a/src/nvim/eval/funcs.c
+++ b/src/nvim/eval/funcs.c
--- a/src/nvim/eval/funcs.h
+++ b/src/nvim/eval/funcs.h
@@ -1,11 +1,12 @@
 #ifndef NVIM_EVAL_FUNCS_H
 #define NVIM_EVAL_FUNCS_H

+#include "nvim/api/private/dispatch.h"
 #include "nvim/buffer_defs.h"
 #include "nvim/eval/typval.h"

 /// Prototype of C function that implements VimL function
-typedef void (*VimLFunc)(typval_T *args, typval_T *rvar, FunPtr data);
+typedef void (*VimLFunc)(typval_T *args, typval_T *rvar, EvalFuncData data);

 /// Special flags for base_arg @see EvalFuncDef
 #define BASE_NONE 0          ///< Not a method (no base argument).
@@ -19,7 +20,7 @@ typedef struct {
  uint8_t base_arg;  ///< Method base arg # (1-indexed), BASE_NONE or BASE_LAST.
  bool fast;         ///< Can be run in |api-fast| events
  VimLFunc func;     ///< Function implementation.
-  FunPtr data;       ///< Userdata for function implementation.
+  EvalFuncData data; ///< Userdata for function implementation.
 } EvalFuncDef;

 #ifdef INCLUDE_GENERATED_DECLARATIONS
--- a/src/nvim/eval/typval.c
+++ b/src/nvim/eval/typval.c
@@ -831,7 +831,7 @@ int tv_list_join(garray_T *const gap, list_T *const l, const char *const sep)
 }

 /// "join()" function
-void f_join(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_join(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  if (argvars[0].v_type != VAR_LIST) {
    emsg(_(e_listreq));
@@ -855,7 +855,7 @@ void f_join(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 }

 /// "list2str()" function
-void f_list2str(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_list2str(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  garray_T ga;

@@ -1267,13 +1267,13 @@ theend:
 }

 /// "sort"({list})" function
-void f_sort(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_sort(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  do_sort_uniq(argvars, rettv, true);
 }

 /// "uniq({list})" function
-void f_uniq(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_uniq(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  do_sort_uniq(argvars, rettv, false);
 }
@@ -2806,25 +2806,25 @@ static void tv_dict_list(typval_T *const tv, typval_T *const rettv, const DictLi
 }

 /// "items(dict)" function
-void f_items(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_items(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  tv_dict_list(argvars, rettv, 2);
 }

 /// "keys()" function
-void f_keys(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_keys(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  tv_dict_list(argvars, rettv, 0);
 }

 /// "values(dict)" function
-void f_values(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_values(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  tv_dict_list(argvars, rettv, 1);
 }

 /// "has_key()" function
-void f_has_key(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_has_key(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  if (argvars[0].v_type != VAR_DICT) {
    emsg(_(e_dictreq));
--- a/src/nvim/eval/typval.h
+++ b/src/nvim/eval/typval.h
@@ -25,9 +25,6 @@
 typedef int64_t varnumber_T;
 typedef uint64_t uvarnumber_T;

-/// Type used for VimL VAR_FLOAT values
-typedef double float_T;
-
 /// Refcount for dict or list that should not be freed
 enum { DO_NOT_FREE_CNT = (INT_MAX / 2), };

--- a/src/nvim/eval/vars.c
+++ b/src/nvim/eval/vars.c
@@ -1702,7 +1702,7 @@ bool var_exists(const char *var)
 }

 /// "gettabvar()" function
-void f_gettabvar(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_gettabvar(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  const char *const varname = tv_get_string_chk(&argvars[1]);
  tabpage_T *const tp = find_tabpage((int)tv_get_number_chk(&argvars[0], NULL));
@@ -1716,19 +1716,19 @@ void f_gettabvar(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 }

 /// "gettabwinvar()" function
-void f_gettabwinvar(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_gettabwinvar(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  getwinvar(argvars, rettv, 1);
 }

 /// "getwinvar()" function
-void f_getwinvar(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_getwinvar(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  getwinvar(argvars, rettv, 0);
 }

 /// "getbufvar()" function
-void f_getbufvar(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_getbufvar(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  const char *const varname = tv_get_string_chk(&argvars[1]);
  buf_T *const buf = tv_get_buf_from_arg(&argvars[0]);
@@ -1737,7 +1737,7 @@ void f_getbufvar(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 }

 /// "settabvar()" function
-void f_settabvar(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_settabvar(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  rettv->vval.v_number = 0;

@@ -1768,19 +1768,19 @@ void f_settabvar(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 }

 /// "settabwinvar()" function
-void f_settabwinvar(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_settabwinvar(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  setwinvar(argvars, rettv, 1);
 }

 /// "setwinvar()" function
-void f_setwinvar(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_setwinvar(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  setwinvar(argvars, rettv, 0);
 }

 /// "setbufvar()" function
-void f_setbufvar(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_setbufvar(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  if (check_secure()
      || !tv_check_str_or_nr(&argvars[0])) {
--- a/src/nvim/ex_docmd.c
+++ b/src/nvim/ex_docmd.c
@@ -3047,7 +3047,7 @@ int cmd_exists(const char *const name)
 }

 /// "fullcommand" function
-void f_fullcommand(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_fullcommand(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  char *name = argvars[0].vval.v_string;

--- a/src/nvim/fold.c
+++ b/src/nvim/fold.c
@@ -3212,19 +3212,19 @@ static void foldclosed_both(typval_T *argvars, typval_T *rettv, int end)
 }

 /// "foldclosed()" function
-void f_foldclosed(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_foldclosed(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  foldclosed_both(argvars, rettv, false);
 }

 /// "foldclosedend()" function
-void f_foldclosedend(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_foldclosedend(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  foldclosed_both(argvars, rettv, true);
 }

 /// "foldlevel()" function
-void f_foldlevel(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_foldlevel(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  const linenr_T lnum = tv_get_lnum(argvars);
  if (lnum >= 1 && lnum <= curbuf->b_ml.ml_line_count) {
@@ -3233,7 +3233,7 @@ void f_foldlevel(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 }

 /// "foldtext()" function
-void f_foldtext(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_foldtext(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  rettv->v_type = VAR_STRING;
  rettv->vval.v_string = NULL;
@@ -3279,7 +3279,7 @@ void f_foldtext(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 }

 /// "foldtextresult(lnum)" function
-void f_foldtextresult(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_foldtextresult(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  char_u buf[FOLD_TEXT_LEN];
  static bool entered = false;
--- a/src/nvim/generators/c_grammar.lua
+++ b/src/nvim/generators/c_grammar.lua
@@ -26,6 +26,7 @@ local c_id = (
 local c_void = P('void')
 local c_param_type = (
  ((P('Error') * fill * P('*') * fill) * Cc('error')) +
+  ((P('Arena') * fill * P('*') * fill) * Cc('arena')) +
  C((P('const ') ^ -1) * (c_id) * (ws ^ 1) * P('*')) +
  (C(c_id) * (ws ^ 1))
  )
--- a/src/nvim/generators/gen_api_dispatch.lua
+++ b/src/nvim/generators/gen_api_dispatch.lua
@@ -17,6 +17,7 @@ local nvimdir = arg[1]
 package.path = nvimdir .. '/?.lua;' .. package.path

 _G.vim = loadfile(nvimdir..'/../../runtime/lua/vim/shared.lua')()
+_G.vim.inspect = loadfile(nvimdir..'/../../runtime/lua/vim/inspect.lua')()

 local hashy = require'generators.hashy'

@@ -72,6 +73,11 @@ for i = 6, #arg do
        -- for specifying errors
        fn.parameters[#fn.parameters] = nil
      end
+      if #fn.parameters ~= 0 and fn.parameters[#fn.parameters][1] == 'arena' then
+        -- return value is allocated in an arena
+        fn.arena_return = true
+        fn.parameters[#fn.parameters] = nil
+      end
    end
  end
  input:close()
@@ -210,7 +216,7 @@ for i = 1, #functions do
  if fn.impl_name == nil and fn.remote then
    local args = {}

-    output:write('Object handle_'..fn.name..'(uint64_t channel_id, Array args, Error *error)')
+    output:write('Object handle_'..fn.name..'(uint64_t channel_id, Array args, Arena* arena, Error *error)')
    output:write('\n{')
    output:write('\n#if MIN_LOG_LEVEL <= LOGLVL_DBG')
    output:write('\n  logmsg(LOGLVL_DBG, "RPC: ", NULL, -1, true, "ch %" PRIu64 ": invoke '
@@ -319,6 +325,10 @@ for i = 1, #functions do
      output:write(call_args)
    end

+    if fn.arena_return then
+        output:write(', arena')
+    end
+
    if fn.can_fail then
      -- if the function can fail, also pass a pointer to the local error object
      if #args > 0 then
@@ -355,11 +365,12 @@ local hashorder, hashfun = hashy.hashy_hash("msgpack_rpc_get_handler_for", vim.t
  return "method_handlers["..idx.."].name"
 end)

-output:write("static const MsgpackRpcRequestHandler method_handlers[] = {\n")
-for _, name in ipairs(hashorder) do
+output:write("const MsgpackRpcRequestHandler method_handlers[] = {\n")
+for n, name in ipairs(hashorder) do
  local fn = remote_fns[name]
+  fn.handler_id = n-1
  output:write('  { .name = "'..name..'", .fn = handle_'..  (fn.impl_name or fn.name)..
-               ', .fast = '..tostring(fn.fast)..'},\n')
+               ', .fast = '..tostring(fn.fast)..', .arena_return = '..tostring(not not fn.arena_return)..'},\n')
 end
 output:write("};\n\n")
 output:write(hashfun)
@@ -400,6 +411,10 @@ output:write([[
 #include "nvim/api/private/helpers.h"
 #include "nvim/lua/converter.h"
 #include "nvim/lua/executor.h"
+#include "nvim/memory.h"
+
+static ArenaMem lua_reuse_blk = { 0 };
+
 ]])
 include_headers(output, headers)
 output:write('\n')
@@ -477,6 +492,14 @@ local function process_function(fn)
  if fn.receives_channel_id then
    cparams = 'LUA_INTERNAL_CALL, ' .. cparams
  end
+  if fn.arena_return then
+    cparams = cparams .. '&arena, '
+    write_shifted_output(output, [[
+    Arena arena = ARENA_EMPTY;
+    arena_start(&arena, &lua_reuse_blk);
+    ]])
+  end
+
  if fn.can_fail then
    cparams = cparams .. '&err'
  else
@@ -511,15 +534,21 @@ local function process_function(fn)
    else
      return_type = fn.return_type
    end
+    local free_retval
+    if fn.arena_return then
+      free_retval = "arena_mem_free(arena_finish(&arena), &lua_reuse_blk);"
+    else
+      free_retval = "api_free_"..return_type:lower().."(ret);"
+    end
    write_shifted_output(output, string.format([[
    const %s ret = %s(%s);
    nlua_push_%s(lstate, ret, true);
-    api_free_%s(ret);
+  %s
  %s
  %s
    return 1;
-    ]], fn.return_type, fn.name, cparams, return_type, return_type:lower(),
-        free_at_exit_code, err_throw_code))
+    ]], fn.return_type, fn.name, cparams, return_type,
+        free_retval, free_at_exit_code, err_throw_code))
  else
    write_shifted_output(output, string.format([[
    %s(%s);
--- a/src/nvim/generators/gen_eval.lua
+++ b/src/nvim/generators/gen_eval.lua
@@ -28,13 +28,20 @@ local hashy = require'generators.hashy'
 local hashpipe = io.open(funcsfname, 'wb')

 local funcs = require('eval').funcs
+for _, func in pairs(funcs) do
+  if func.float_func then
+    func.func = "float_op_wrapper"
+    func.data = "{ .float_func = &"..func.float_func.." }"
+  end
+end
+
 local metadata = mpack.unpack(io.open(metadata_file, 'rb'):read("*all"))
 for _,fun in ipairs(metadata) do
  if fun.eval then
    funcs[fun.name] = {
      args=#fun.parameters,
      func='api_wrapper',
-      data='&handle_'..fun.name,
+      data='{ .api_handler = &method_handlers['..fun.handler_id..'] }'
    }
  end
 end
@@ -60,12 +67,12 @@ for _, name in ipairs(neworder) do
  end
  local base = def.base or "BASE_NONE"
  local func = def.func or ('f_' .. name)
-  local data = def.data or "NULL"
+  local data = def.data or "{ .nullptr = NULL }"
  local fast = def.fast and 'true' or 'false'
-  hashpipe:write(('  { "%s", %s, %s, %s, %s, &%s, (FunPtr)%s },\n')
+  hashpipe:write(('  { "%s", %s, %s, %s, %s, &%s, %s },\n')
                  :format(name, args[1], args[2], base, fast, func, data))
 end
-hashpipe:write('  { NULL, 0, 0, BASE_NONE, false, NULL, NULL },\n')
+hashpipe:write('  { NULL, 0, 0, BASE_NONE, false, NULL, { .nullptr = NULL } },\n')
 hashpipe:write("};\n\n")
 hashpipe:write(hashfun)
 hashpipe:close()
--- a/src/nvim/getchar.c
+++ b/src/nvim/getchar.c
@@ -1810,13 +1810,13 @@ static void getchar_common(typval_T *argvars, typval_T *rettv)
 }

 /// "getchar()" function
-void f_getchar(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_getchar(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  getchar_common(argvars, rettv);
 }

 /// "getcharstr()" function
-void f_getcharstr(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_getcharstr(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  getchar_common(argvars, rettv);

@@ -1836,7 +1836,7 @@ void f_getcharstr(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 }

 /// "getcharmod()" function
-void f_getcharmod(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_getcharmod(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  rettv->vval.v_number = mod_mask;
 }
--- a/src/nvim/insexpand.c
+++ b/src/nvim/insexpand.c
@@ -2256,7 +2256,7 @@ static void set_completion(colnr_T startcol, list_T *list)
 }

 /// "complete()" function
-void f_complete(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_complete(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  if ((State & MODE_INSERT) == 0) {
    emsg(_("E785: complete() can only be used in Insert mode"));
@@ -2280,13 +2280,13 @@ void f_complete(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 }

 /// "complete_add()" function
-void f_complete_add(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_complete_add(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  rettv->vval.v_number = ins_compl_add_tv(&argvars[0], 0, false);
 }

 /// "complete_check()" function
-void f_complete_check(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_complete_check(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  int saved = RedrawingDisabled;

@@ -2441,7 +2441,7 @@ static void get_complete_info(list_T *what_list, dict_T *retdict)
 }

 /// "complete_info()" function
-void f_complete_info(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_complete_info(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  tv_dict_alloc_ret(rettv);

--- a/src/nvim/mapping.c
+++ b/src/nvim/mapping.c
@@ -1967,7 +1967,7 @@ char_u *check_map(char_u *keys, int mode, int exact, int ign_mod, int abbr, mapb
 }

 /// "hasmapto()" function
-void f_hasmapto(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_hasmapto(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  const char *mode;
  const char *const name = tv_get_string(&argvars[0]);
@@ -2127,7 +2127,7 @@ static void get_maparg(typval_T *argvars, typval_T *rettv, int exact)
 }

 /// "mapset()" function
-void f_mapset(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_mapset(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  char buf[NUMBUFLEN];
  const char *which = tv_get_string_buf_chk(&argvars[0], buf);
@@ -2195,13 +2195,13 @@ void f_mapset(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 }

 /// "maparg()" function
-void f_maparg(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_maparg(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  get_maparg(argvars, rettv, true);
 }

 /// "mapcheck()" function
-void f_mapcheck(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_mapcheck(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  get_maparg(argvars, rettv, false);
 }
--- a/src/nvim/match.c
+++ b/src/nvim/match.c
@@ -859,7 +859,7 @@ static int matchadd_dict_arg(typval_T *tv, const char **conceal_char, win_T **wi
 }

 /// "clearmatches()" function
-void f_clearmatches(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_clearmatches(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  win_T *win = get_optional_window(argvars, 0);

@@ -869,7 +869,7 @@ void f_clearmatches(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 }

 /// "getmatches()" function
-void f_getmatches(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_getmatches(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  matchitem_T *cur;
  int i;
@@ -924,7 +924,7 @@ void f_getmatches(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 }

 /// "setmatches()" function
-void f_setmatches(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_setmatches(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  dict_T *d;
  list_T *s = NULL;
@@ -1027,7 +1027,7 @@ void f_setmatches(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 }

 /// "matchadd()" function
-void f_matchadd(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_matchadd(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  char grpbuf[NUMBUFLEN];
  char patbuf[NUMBUFLEN];
@@ -1069,7 +1069,7 @@ void f_matchadd(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 }

 /// "matchaddpo()" function
-void f_matchaddpos(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_matchaddpos(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  rettv->vval.v_number = -1;

@@ -1120,7 +1120,7 @@ void f_matchaddpos(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 }

 /// "matcharg()" function
-void f_matcharg(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_matcharg(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  const int id = (int)tv_get_number(&argvars[0]);

@@ -1143,7 +1143,7 @@ void f_matcharg(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 }

 /// "matchdelete()" function
-void f_matchdelete(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_matchdelete(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  win_T *win = get_optional_window(argvars, 1);
  if (win == NULL) {
--- a/src/nvim/mbyte.c
+++ b/src/nvim/mbyte.c
@@ -2748,7 +2748,7 @@ static int tv_nr_compare(const void *a1, const void *a2)
 }

 /// "setcellwidths()" function
-void f_setcellwidths(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_setcellwidths(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  if (argvars[0].v_type != VAR_LIST || argvars[0].vval.v_list == NULL) {
    emsg(_(e_listreq));
@@ -2860,7 +2860,7 @@ void f_setcellwidths(typval_T *argvars, typval_T *rettv, FunPtr fptr)
  redraw_all_later(NOT_VALID);
 }

-void f_charclass(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_charclass(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  if (tv_check_for_string(&argvars[0]) == FAIL
      || argvars[0].vval.v_string == NULL) {
--- a/src/nvim/memory.c
+++ b/src/nvim/memory.c
@@ -534,15 +534,18 @@ void arena_start(Arena *arena, ArenaMem *reuse_blk)
  if (reuse_blk && *reuse_blk) {
    arena->cur_blk = (char *)(*reuse_blk);
    *reuse_blk = NULL;
+    arena->size = ARENA_BLOCK_SIZE;
+    arena->pos = 0;
+
+    // address is the same as as (struct consumed_blk *)arena->cur_blk
+    struct consumed_blk *blk = arena_alloc(arena, sizeof(struct consumed_blk), true);
+    assert((char *)blk == (char *)arena->cur_blk);
+    blk->prev = NULL;
  } else {
-    arena->cur_blk = xmalloc(ARENA_BLOCK_SIZE);
+    arena->cur_blk = NULL;
+    arena->size = 0;
+    arena->pos = 0;
  }
-  arena->pos = 0;
-  arena->size = ARENA_BLOCK_SIZE;
-  // address is the same as as (struct consumed_blk *)arena->cur_blk
-  struct consumed_blk *blk = arena_alloc(arena, sizeof(struct consumed_blk), true);
-  assert((char *)blk == (char *)arena->cur_blk);
-  blk->prev = NULL;
 }

 /// Finnish the allocations in an arena.
@@ -558,17 +561,35 @@ ArenaMem arena_finish(Arena *arena)
  return res;
 }

+void alloc_block(Arena *arena)
+{
+  struct consumed_blk *prev_blk = (struct consumed_blk *)arena->cur_blk;
+  arena->cur_blk = xmalloc(ARENA_BLOCK_SIZE);
+  arena->pos = 0;
+  arena->size = ARENA_BLOCK_SIZE;
+  struct consumed_blk *blk = arena_alloc(arena, sizeof(struct consumed_blk), true);
+  blk->prev = prev_blk;
+  arena_alloc_count++;
+}
+
+/// @param size if zero, will still return a non-null pointer, but not a unique one
 void *arena_alloc(Arena *arena, size_t size, bool align)
 {
  if (align) {
    arena->pos = (arena->pos + (ARENA_ALIGN - 1)) & ~(ARENA_ALIGN - 1);
  }
-  if (arena->pos + size > arena->size) {
-    if (size > (arena->size - sizeof(struct consumed_blk)) >> 1) {
+  if (arena->pos + size > arena->size || !arena->cur_blk) {
+    if (size > (ARENA_BLOCK_SIZE - sizeof(struct consumed_blk)) >> 1) {
      // if allocation is too big, allocate a large block with the requested
      // size, but still with block pointer head. We do this even for
      // arena->size / 2, as there likely is space left for the next
      // small allocation in the current block.
+      if (!arena->cur_blk) {
+        // to simplify free-list management, arena->cur_blk must
+        // always be a normal, ARENA_BLOCK_SIZE sized, block
+        alloc_block(arena);
+      }
+      arena_alloc_count++;
      char *alloc = xmalloc(size + sizeof(struct consumed_blk));
      struct consumed_blk *cur_blk = (struct consumed_blk *)arena->cur_blk;
      struct consumed_blk *fix_blk = (struct consumed_blk *)alloc;
@@ -576,12 +597,7 @@ void *arena_alloc(Arena *arena, size_t size, bool align)
      cur_blk->prev = fix_blk;
      return (alloc + sizeof(struct consumed_blk));
    } else {
-      struct consumed_blk *prev_blk = (struct consumed_blk *)arena->cur_blk;
-      arena->cur_blk = xmalloc(ARENA_BLOCK_SIZE);
-      arena->pos = 0;
-      arena->size = ARENA_BLOCK_SIZE;
-      struct consumed_blk *blk = arena_alloc(arena, sizeof(struct consumed_blk), true);
-      blk->prev = prev_blk;
+      alloc_block(arena);
    }
  }

--- a/src/nvim/memory.h
+++ b/src/nvim/memory.h
@@ -6,6 +6,8 @@
 #include <stdint.h>  // for uint8_t
 #include <time.h>  // for time_t

+#include "nvim/macros.h"
+
 /// `malloc()` function signature
 typedef void *(*MemMalloc)(size_t);

@@ -37,6 +39,8 @@ extern MemRealloc mem_realloc;
 extern bool entered_free_all_mem;
 #endif

+EXTERN size_t arena_alloc_count INIT(=0);
+
 typedef struct consumed_blk {
  struct consumed_blk *prev;
 } *ArenaMem;
--- a/src/nvim/menu.c
+++ b/src/nvim/menu.c
@@ -1945,7 +1945,7 @@ static void menuitem_getinfo(const char *menu_name, const vimmenu_T *menu, int m

 /// "menu_info()" function
 /// Return information about a menu (including all the child menus)
-void f_menu_info(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_menu_info(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  tv_dict_alloc_ret(rettv);
  dict_T *const retdict = rettv->vval.v_dict;
--- a/src/nvim/msgpack_rpc/channel.c
+++ b/src/nvim/msgpack_rpc/channel.c
@@ -304,7 +304,8 @@ static void handle_request(Channel *channel, Unpacker *p, Array args)
  evdata->channel = channel;
  evdata->handler = p->handler;
  evdata->args = args;
-  evdata->used_mem = arena_finish(&p->arena);
+  evdata->used_mem = p->arena;
+  p->arena = (Arena)ARENA_EMPTY;
  evdata->request_id = p->request_id;
  channel_incref(channel);
  if (p->handler.fast) {
@@ -344,7 +345,8 @@ static void request_event(void **argv)
    // channel was closed, abort any pending requests
    goto free_ret;
  }
-  Object result = handler.fn(channel->id, e->args, &error);
+
+  Object result = handler.fn(channel->id, e->args, &e->used_mem, &error);
  if (e->type == kMessageTypeRequest || ERROR_SET(&error)) {
    // Send the response.
    msgpack_packer response;
@@ -355,13 +357,14 @@ static void request_event(void **argv)
                                              &error,
                                              result,
                                              &out_buffer));
-  } else {
+  }
+  if (!handler.arena_return) {
    api_free_object(result);
  }

 free_ret:
-  // e->args is allocated in an arena
-  arena_mem_free(e->used_mem, &channel->rpc.unpacker->reuse_blk);
+  // e->args (and possibly result) are allocated in an arena
+  arena_mem_free(arena_finish(&e->used_mem), &channel->rpc.unpacker->reuse_blk);
  channel_decref(channel);
  xfree(e);
  api_clear_error(&error);
@@ -624,7 +627,6 @@ static WBuffer *serialize_response(uint64_t channel_id, MessageType type, uint32
                                   1,  // responses only go though 1 channel
                                   xfree);
  msgpack_sbuffer_clear(sbuffer);
-  api_free_object(arg);
  return rv;
 }

--- a/src/nvim/msgpack_rpc/channel_defs.h
+++ b/src/nvim/msgpack_rpc/channel_defs.h
@@ -27,7 +27,7 @@ typedef struct {
  MsgpackRpcRequestHandler handler;
  Array args;
  uint32_t request_id;
-  ArenaMem used_mem;
+  Arena used_mem;
 } RequestEvent;

 typedef struct {
--- a/src/nvim/quickfix.c
+++ b/src/nvim/quickfix.c
@@ -7169,14 +7169,14 @@ static void get_qf_loc_list(int is_qf, win_T *wp, typval_T *what_arg, typval_T *
 }

 /// "getloclist()" function
-void f_getloclist(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_getloclist(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  win_T *wp = find_win_by_nr_or_id(&argvars[0]);
  get_qf_loc_list(false, wp, &argvars[1], rettv);
 }

 /// "getqflist()" functions
-void f_getqflist(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_getqflist(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  get_qf_loc_list(true, NULL, &argvars[0], rettv);
 }
@@ -7263,7 +7263,7 @@ skip_args:
 }

 /// "setloclist()" function
-void f_setloclist(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_setloclist(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  rettv->vval.v_number = -1;

@@ -7274,7 +7274,7 @@ void f_setloclist(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 }

 /// "setqflist()" function
-void f_setqflist(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_setqflist(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  set_qf_ll_list(NULL, argvars, rettv);
 }
--- a/src/nvim/search.c
+++ b/src/nvim/search.c
@@ -4637,7 +4637,7 @@ static void update_search_stat(int dirc, pos_T *pos, pos_T *cursor_pos, searchst
 }

 // "searchcount()" function
-void f_searchcount(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_searchcount(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  pos_T pos = curwin->w_cursor;
  char_u *pattern = NULL;
@@ -5287,13 +5287,13 @@ static void do_fuzzymatch(const typval_T *const argvars, typval_T *const rettv,
 }

 /// "matchfuzzy()" function
-void f_matchfuzzy(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_matchfuzzy(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  do_fuzzymatch(argvars, rettv, false);
 }

 /// "matchfuzzypos()" function
-void f_matchfuzzypos(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_matchfuzzypos(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  do_fuzzymatch(argvars, rettv, true);
 }
--- a/src/nvim/sign.c
+++ b/src/nvim/sign.c
@@ -1964,7 +1964,7 @@ static void sign_define_multiple(list_T *l, list_T *retlist)
 }

 /// "sign_define()" function
-void f_sign_define(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_sign_define(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  const char *name;

@@ -1995,7 +1995,7 @@ void f_sign_define(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 }

 /// "sign_getdefined()" function
-void f_sign_getdefined(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_sign_getdefined(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  const char *name = NULL;

@@ -2009,7 +2009,7 @@ void f_sign_getdefined(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 }

 /// "sign_getplaced()" function
-void f_sign_getplaced(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_sign_getplaced(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  buf_T *buf = NULL;
  dict_T *dict;
@@ -2067,7 +2067,7 @@ void f_sign_getplaced(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 }

 /// "sign_jump()" function
-void f_sign_jump(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_sign_jump(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  int sign_id;
  char *sign_group = NULL;
@@ -2225,7 +2225,7 @@ cleanup:
 }

 /// "sign_place()" function
-void f_sign_place(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_sign_place(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  dict_T *dict = NULL;

@@ -2243,7 +2243,7 @@ void f_sign_place(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 }

 /// "sign_placelist()" function.  Place multiple signs.
-void f_sign_placelist(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_sign_placelist(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  int sign_id;

@@ -2283,7 +2283,7 @@ static void sign_undefine_multiple(list_T *l, list_T *retlist)
 }

 /// "sign_undefine()" function
-void f_sign_undefine(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_sign_undefine(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  const char *name;

@@ -2373,7 +2373,7 @@ cleanup:
 }

 /// "sign_unplace()" function
-void f_sign_unplace(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_sign_unplace(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  dict_T *dict = NULL;

@@ -2396,7 +2396,7 @@ void f_sign_unplace(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 }

 /// "sign_unplacelist()" function
-void f_sign_unplacelist(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_sign_unplacelist(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  int retval;

--- a/src/nvim/testing.c
+++ b/src/nvim/testing.c
@@ -326,19 +326,19 @@ static int assert_beeps(typval_T *argvars, bool no_beep)
 }

 /// "assert_beeps(cmd [, error])" function
-void f_assert_beeps(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_assert_beeps(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  rettv->vval.v_number = assert_beeps(argvars, false);
 }

 /// "assert_nobeep(cmd [, error])" function
-void f_assert_nobeep(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_assert_nobeep(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  rettv->vval.v_number = assert_beeps(argvars, true);
 }

 /// "assert_equal(expected, actual[, msg])" function
-void f_assert_equal(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_assert_equal(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  rettv->vval.v_number = assert_equal_common(argvars, ASSERT_EQUAL);
 }
@@ -433,19 +433,19 @@ static int assert_equalfile(typval_T *argvars)
 }

 /// "assert_equalfile(fname-one, fname-two[, msg])" function
-void f_assert_equalfile(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_assert_equalfile(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  rettv->vval.v_number = assert_equalfile(argvars);
 }

 /// "assert_notequal(expected, actual[, msg])" function
-void f_assert_notequal(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_assert_notequal(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  rettv->vval.v_number = assert_equal_common(argvars, ASSERT_NOTEQUAL);
 }

 /// "assert_exception(string[, msg])" function
-void f_assert_exception(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_assert_exception(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  garray_T ga;

@@ -468,7 +468,7 @@ void f_assert_exception(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 }

 /// "assert_fails(cmd [, error [, msg]])" function
-void f_assert_fails(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_assert_fails(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  const char *const cmd = tv_get_string_chk(&argvars[0]);
  garray_T ga;
@@ -513,7 +513,7 @@ void f_assert_fails(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 }

 // "assert_false(actual[, msg])" function
-void f_assert_false(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_assert_false(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  rettv->vval.v_number = assert_bool(argvars, false);
 }
@@ -574,25 +574,25 @@ static int assert_inrange(typval_T *argvars)
 }

 /// "assert_inrange(lower, upper[, msg])" function
-void f_assert_inrange(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_assert_inrange(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  rettv->vval.v_number = assert_inrange(argvars);
 }

 /// "assert_match(pattern, actual[, msg])" function
-void f_assert_match(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_assert_match(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  rettv->vval.v_number = assert_match_common(argvars, ASSERT_MATCH);
 }

 /// "assert_notmatch(pattern, actual[, msg])" function
-void f_assert_notmatch(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_assert_notmatch(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  rettv->vval.v_number = assert_match_common(argvars, ASSERT_NOTMATCH);
 }

 /// "assert_report(msg)" function
-void f_assert_report(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_assert_report(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  garray_T ga;

@@ -604,13 +604,13 @@ void f_assert_report(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 }

 /// "assert_true(actual[, msg])" function
-void f_assert_true(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_assert_true(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  rettv->vval.v_number = assert_bool(argvars, true);
 }

 /// "test_garbagecollect_now()" function
-void f_test_garbagecollect_now(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+void f_test_garbagecollect_now(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
  // This is dangerous, any Lists and Dicts used internally may be freed
  // while still in use.
@@ -618,7 +618,7 @@ void f_test_garbagecollect_now(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 }

 /// "test_write_list_log()" function
-void f_test_write_list_log(typval_T *const argvars, typval_T *const rettv, FunPtr fptr)
+void f_test_write_list_log(typval_T *const argvars, typval_T *const rettv, EvalFuncData fptr)
 {
  const char *const fname = tv_get_string_chk(&argvars[0]);
  if (fname == NULL) {
--- a/src/nvim/types.h
+++ b/src/nvim/types.h
@@ -22,7 +22,17 @@ typedef int handle_T;
 // absent callback etc.
 typedef int LuaRef;

-typedef void (*FunPtr)(void);
+/// Type used for VimL VAR_FLOAT values
+typedef double float_T;
+
+typedef struct MsgpackRpcRequestHandler MsgpackRpcRequestHandler;
+
+typedef union {
+  float_T (*float_func)(float_T);
+  const MsgpackRpcRequestHandler *api_handler;
+  void *nullptr;
+} EvalFuncData;
+

 typedef handle_T NS;

--- a/src/nvim/ui_client.c
+++ b/src/nvim/ui_client.c
@@ -55,7 +55,7 @@ UIClientHandler ui_client_get_redraw_handler(const char *name, size_t name_len,
 /// async 'redraw' events, which are expected when nvim acts as an ui client.
 /// get handled in msgpack_rpc/unpacker.c and directly dispatched to handlers
 /// of specific ui events, like ui_client_event_grid_resize and so on.
-Object handle_ui_client_redraw(uint64_t channel_id, Array args, Error *error)
+Object handle_ui_client_redraw(uint64_t channel_id, Array args, Arena *arena, Error *error)
 {
  api_set_error(error, kErrorTypeValidation, "'redraw' cannot be sent as a request");
  return NIL;