diff --git a/test/lib/ffi/ffi_err.lua b/test/lib/ffi/err.lua
similarity index 63%
rename from test/lib/ffi/ffi_err.lua
rename to test/lib/ffi/err.lua
index bd23658a2d..44723657c0 100644
--- a/test/lib/ffi/ffi_err.lua
+++ b/test/lib/ffi/err.lua
@@ -1,7 +1,6 @@
 local ffi = require("ffi")
 
--- error in FFI metamethod: don't print metamethod frame.
-do
+do --- error in FFI metamethod: don't print metamethod frame.
   local ok, err = xpcall(function()
     local x = (1ll).foo
   end, debug.traceback)
@@ -9,8 +8,7 @@ do
   assert(not string.find(err, "__index"))
 end
 
--- tailcall in regular metamethod: keep metamethod frame.
-do
+do --- tailcall in regular metamethod: keep metamethod frame.
   local ok, err = xpcall(function()
     local t = setmetatable({}, {__index = function() return rawget("x") end })
     local y = t[1]
@@ -19,13 +17,12 @@ do
   assert(string.find(err, "__index"))
 end
 
--- error in FFI metamethod: set correct PC.
-do
+do --- error in FFI metamethod: set correct PC.
   ffi.cdef[[
-typedef struct { int x; int y; } point;
-point strchr(point* op1, point* op2);
+typedef struct { int x; int y; } ffi_err_point;
+ffi_err_point ffi_err_strchr(ffi_err_point* op1, ffi_err_point* op2) asm("strchr");
 ]]
-  local point = ffi.metatype("point", { __add = ffi.C.strchr })
+  local point = ffi.metatype("ffi_err_point", { __add = ffi.C.ffi_err_strchr })
   local function foo()
     local p = point{ 3, 4 }
     local r = p + p
diff --git a/test/lib/ffi/index b/test/lib/ffi/index
index 0ccd1ab531..c4091fb727 100644
--- a/test/lib/ffi/index
+++ b/test/lib/ffi/index
@@ -1,6 +1,10 @@
 bit64.lua +bit
 copy_fill.lua
+err.lua
+istype.lua
 jit_array.lua
+jit_complex.lua
+jit_misc.lua
 jit_struct.lua
 meta_tostring.lua
 redir.lua
diff --git a/test/lib/ffi/ffi_istype.lua b/test/lib/ffi/istype.lua
similarity index 84%
rename from test/lib/ffi/ffi_istype.lua
rename to test/lib/ffi/istype.lua
index fb538bdd4e..5aba7759e7 100644
--- a/test/lib/ffi/ffi_istype.lua
+++ b/test/lib/ffi/istype.lua
@@ -1,12 +1,6 @@
 local ffi = require("ffi")
 
-ffi.cdef[[
-typedef int arr_t[10];
-typedef const arr_t carr_t;
-typedef struct { int x; } struct_t;
-]]
-
-do
+do --- 1
   local void_t = ffi.typeof("void")
   assert(ffi.istype(void_t, void_t))
   assert(ffi.istype("const void", void_t))
@@ -15,7 +9,7 @@ do
   assert(ffi.istype("double", 1.5) == false) -- 2nd arg is a number.
 end
 
-do
+do --- 2
   local i8_t = ffi.typeof("int8_t")
   local u8_t = ffi.typeof("uint8_t")
   local i32_t = ffi.typeof("int32_t")
@@ -32,7 +26,7 @@ do
   assert(ffi.istype("long long", ffi.typeof("int64_t")))
 end
 
-do
+do --- 3
   local ptr_t = ffi.typeof("int *")
   local p = ptr_t()
   assert(ffi.istype(ptr_t, ptr_t) == true)
@@ -46,9 +40,15 @@ do
   assert(ffi.istype("void *", ptr_t) == false)
 end
 
-do
-  local arr_t = ffi.typeof("arr_t")
-  local carr_t = ffi.typeof("carr_t")
+do --- 4
+  ffi.cdef[[
+typedef int istype_arr_t[10];
+typedef const istype_arr_t istype_carr_t;
+typedef struct { int x; } istype_struct_t;
+]]
+
+  local arr_t = ffi.typeof("istype_arr_t")
+  local carr_t = ffi.typeof("istype_carr_t")
   assert(ffi.istype(arr_t, arr_t) == true)
   assert(ffi.istype("int[10]", arr_t) == true)
 
@@ -60,16 +60,16 @@ do
   assert(ffi.istype("volatile int[10]", arr_t) == true)
   assert(ffi.istype(carr_t, arr_t) == true)
 
-  local struct_t = ffi.typeof("struct_t")
-  local structp_t = ffi.typeof("struct_t *")
+  local struct_t = ffi.typeof("istype_struct_t")
+  local structp_t = ffi.typeof("istype_struct_t *")
   assert(ffi.istype(struct_t, struct_t) == true)
-  assert(ffi.istype("const struct_t", struct_t) == true)
+  assert(ffi.istype("const istype_struct_t", struct_t) == true)
   assert(ffi.istype("struct { int x; }", struct_t) == false)
   assert(ffi.istype(struct_t, structp_t) == true) -- struct ptr is ok for struct.
   assert(ffi.istype(structp_t, struct_t) == false)
 end
 
-do
+do --- 5
   local int_t = ffi.typeof("int")
   local t = {}
   for i=1,200 do t[i] = int_t() end
@@ -86,4 +86,3 @@ do
   for i=1,200 do if not ffi.istype(t[i], int_t) then x = x + i end end
   assert(x == 100)
 end
-
diff --git a/test/lib/ffi/ffi_jit_complex.lua b/test/lib/ffi/jit_complex.lua
similarity index 77%
rename from test/lib/ffi/ffi_jit_complex.lua
rename to test/lib/ffi/jit_complex.lua
index 4d3191cbe7..3296f0cbfa 100644
--- a/test/lib/ffi/ffi_jit_complex.lua
+++ b/test/lib/ffi/jit_complex.lua
@@ -4,13 +4,13 @@ local cx = ffi.typeof("complex")
 local cxf = ffi.typeof("complex float")
 
 ffi.cdef[[
-typedef struct cc_t {
-  struct cc_t *next;
+typedef struct jit_complex_chain_t {
+  struct jit_complex_chain_t *next;
   complex c;
-} cc_t;
+} jit_complex_chain_t;
 ]]
 
-do
+do --- field access
   local c = cx(1, 2)
   local x
   for i=1,100 do
@@ -19,8 +19,8 @@ do
   assert(x == 3)
 end
 
-do
-  local cp = ffi.new("cc_t")
+do --- one element circular chain, named indexing
+  local cp = ffi.new("jit_complex_chain_t")
   local p = cp
   p.next = p
   p.c = cx(1, 2)
@@ -34,8 +34,8 @@ do
   assert(y == 200)
 end
 
-do
-  local cp = ffi.new("cc_t")
+do --- one element circular chain, array indexing
+  local cp = ffi.new("jit_complex_chain_t")
   local p = cp
   p.next = p
   p.c = cx(1, 2)
@@ -49,7 +49,7 @@ do
   assert(y == 200)
 end
 
-do
+do --- one-arg initialiser
   local ca = ffi.new("complex[?]", 101)
   for i=1,100 do
     ca[i] = cx(i) -- handled as init single
@@ -63,7 +63,7 @@ do
   assert(y == 0)
 end
 
-do
+do --- two-arg initialiser
   local ca = ffi.new("complex[?]", 101)
   for i=1,100 do
     ca[i] = cx(i, -i)
@@ -77,7 +77,7 @@ do
   assert(y == -5050)
 end
 
-do
+do --- float<>double conversions
   local ca = ffi.new("complex[?]", 101)
   local caf = ffi.new("complex float[?]", 101)
   for i=1,100 do
@@ -93,7 +93,7 @@ do
   assert(y == -2*5050)
 end
 
-do
+do --- Complex struct field
   local s = ffi.new("struct { complex x;}")
   for i=1,100 do
     s.x = 12.5i
@@ -102,10 +102,8 @@ do
   assert(s.x.im == 12.5)
 end
 
--- Index overflow for complex is ignored
-do
+do --- Index overflow for complex is ignored
   local c = cx(1, 2)
   local x
   for i=1e7,1e7+100 do x = c[i] end
 end
-
diff --git a/test/lib/ffi/ffi_jit_misc.lua b/test/lib/ffi/jit_misc.lua
similarity index 90%
rename from test/lib/ffi/ffi_jit_misc.lua
rename to test/lib/ffi/jit_misc.lua
index 800509afcd..41e4737bc7 100644
--- a/test/lib/ffi/ffi_jit_misc.lua
+++ b/test/lib/ffi/jit_misc.lua
@@ -1,6 +1,6 @@
 local ffi = require("ffi")
 
-do
+do --- errno
   ffi.errno(42)
   local x = 0
   for i=1,100 do x = x + ffi.errno() end
@@ -8,7 +8,7 @@ do
   ffi.errno(0)
 end
 
-do
+do --- string
   local a = ffi.new("uint8_t[?]", 101)
   for i=0,99 do a[i] = i end
   local s
@@ -18,7 +18,7 @@ do
   assert(s == "Z[\\]^_`abc")
 end
 
-do
+do --- fill
   local a = ffi.new("uint8_t[?]", 100)
   local x = 0
   for i=0,90 do x = x + a[i]; ffi.fill(a+i, 10, i); x = x + a[i] end
@@ -31,7 +31,7 @@ do
   assert(b[103] == (ffi.abi("le") and 0x343434 or 0x34343400))
 end
 
-do
+do --- copy array elements
   local a = ffi.new("uint8_t[?]", 100)
   local b = ffi.new("uint8_t[?]", 100)
   for i=0,99 do b[i] = i end
@@ -43,7 +43,7 @@ do
   assert(x == 4095)
 end
 
-do
+do --- copy from string
   local a = ffi.new("uint8_t[?]", 100, 42)
   for i=0,90 do ffi.copy(a+i, "abc") end
   local x = 0
@@ -51,7 +51,7 @@ do
   assert(x == 9276)
 end
 
-do
+do --- copy structures
   local tp = ffi.typeof("struct { int x, y; }")
   local a = tp(1, 2)
   local b = tp(3, 4)
@@ -63,7 +63,7 @@ do
   assert(x == 5050)
 end
 
-do
+do --- init struct from first field, complex
   local tp = ffi.typeof("struct { complex x, y; }")
   local cx = ffi.typeof("complex")
   local a = tp(cx(1, 2), cx(3, 4))
@@ -72,7 +72,7 @@ do
   assert(x == 5050)
 end
 
-do
+do --- int array as parameterised type
   local tp = ffi.typeof("int[10]")
   local a = tp(42)
   local b = ffi.new(ffi.typeof("struct { $ x; }", tp))
@@ -80,7 +80,7 @@ do
   assert(b.x[0] == 42 and b.x[9] == 42)
 end
 
-do
+do --- double array as parameterised type
   local tp = ffi.typeof("double[5]")
   local a = tp(42)
   local b = ffi.new(ffi.typeof("struct { $ x; }", tp))
@@ -91,7 +91,7 @@ do
   assert(b.x[0] == 42 and b.x[4] == 42)
 end
 
-do
+do --- abi
   local x, y
   for i=1,100 do x = ffi.abi("32bit"); y = ffi.abi("64bit") end
   assert(x == ffi.abi("32bit"))
@@ -102,9 +102,8 @@ do
   end
 end
 
-do
+do --- typeof constructed typeof
   local ct = ffi.typeof("struct { int x; }")
   local cd = ct()
   for i=1,100 do assert(ffi.typeof(cd) == ct) end
 end
-