libjit

LibJIT is a fairly straightforward, lightweight library for runtime 
compilation with a simple and stable ABI.

Website: https://www.gnu.org/software/libjit/
Platforms supported: Windows, Linux, DOS
Headers to include: jit.bi
Header version: git a8293e141b79c28734a3633a81a43f92f29fc2d7

Example
   '' Simple mul/add example

   #include "jit.bi"

   ' initialize libjit
   Dim context As jit_context_t = jit_context_create()
   jit_context_build_start(context)

   ' define function mul_add(x, y, z)
   Dim params(0 To 2) As jit_type_t = {jit_type_int, jit_type_int, jit_type_int}
   Dim signature As jit_type_t = jit_type_create_signature( _  
      jit_abi_cdecl,  _ ' C-style function
      jit_type_int,   _ ' Return type
      @params(0),     _ ' Parameter array
      3,              _ ' Number of components
      1               _ ' Count references?
   )
   Dim mul_add As jit_function_t = jit_function_create(context, signature)

   ' build function (result = (x*y)+z)
   Dim As jit_value_t x, y, z, temp1, temp2
   x = jit_value_get_param(mul_add, 0)
   y = jit_value_get_param(mul_add, 1)
   temp1 = jit_insn_mul(mul_add, x, y)
   z = jit_value_get_param(mul_add, 2)
   temp2 = jit_insn_add(mul_add, temp1, z)
   jit_insn_return(mul_add, temp2)

   ' compile function function
   jit_function_compile(mul_add)
   jit_context_build_end(context)

   ' call function
   Dim As Integer a=3, b=5, c=2, result
   Dim args(0 To 2) As Integer Ptr = {@a, @b, @c}
   jit_function_apply(mul_add, @args(0), @result)
   Print Using "mul__add(&, &, &) = &"; a; b; c; result

   ' clean up libjit
   jit_context_destroy(context)

   '' GCD calculation example

   #include "jit.bi"

   ' initialize libjit
   Dim context As jit_context_t = jit_context_create()
   jit_context_build_start(context)

   ' define function gcd(x as uinteger, y as uinteger) as uinteger
   Dim params(0 To 1) As jit_type_t = {jit_type_uint, jit_type_uint}
   Dim signature As jit_type_t = jit_type_create_signature( _  
      jit_abi_cdecl,  _ ' C-style function
      jit_type_uint,  _ ' Return type
      @params(0),     _ ' Parameter array
      2,              _ ' Number of components
      1               _ ' Count references?
   )
   Dim gcd As jit_function_t = jit_function_create(context, signature)

   ' build function
   ' check x = y
   Dim As jit_value_t x, y, x_eq_y
   x = jit_value_get_param(gcd, 0)
   y = jit_value_get_param(gcd, 1)
   x_eq_y = jit_insn_eq(gcd, x, y)

   ' if x = y, return x
   Dim label_x_ne_y As jit_label_t = jit_label_undefined
   jit_insn_branch_if_not(gcd, x_eq_y, @label_x_ne_y)
   jit_insn_return(gcd, x)

   ' else if...
   jit_insn_label(gcd, @label_x_ne_y)

   ' check x < y
   Dim As jit_value_t x_lt_y
   Dim label_x_gte_y As jit_label_t = jit_label_undefined
   x_lt_y = jit_insn_lt(gcd, x, y)
   jit_insn_branch_if_not(gcd, x_lt_y, @label_x_gte_y)

   ' if x < y, return gcd(x, y-x)
   Dim As jit_value_t gcd_args(0 To 2), gcd_result
   gcd_args(0) = x
   gcd_args(1) = jit_insn_sub(gcd, y, x)
   gcd_result = jit_insn_call( _
      gcd,          _ ' where we are calling from
      "gcd",        _ ' function name
      gcd,          _ ' function reference
      0,            _ ' signature = auto
      @gcd_args(0), _ ' arguments
      2,            _ ' argument count
      0             _ ' flags = nothing special
   )
   jit_insn_return(gcd, gcd_result)

   ' else...
   jit_insn_label(gcd, @label_x_gte_y)

   ' return gcd(x-y, y)
   gcd_args(0) = jit_insn_sub(gcd, x, y)
   gcd_args(1) = y
   gcd_result = jit_insn_call( _
      gcd,          _ ' where we are calling from
      "gcd",        _ ' function name
      gcd,          _ ' function reference
      0,            _ ' signature = auto
      @gcd_args(0), _ ' arguments
      2,            _ ' argument count
      0             _ ' flags = nothing special
   )
   jit_insn_return(gcd, gcd_result)

   ' compile function
   jit_function_compile(gcd)
   jit_context_build_end(context)

   ' call function
   Dim As jit_uint a=21, b=14, result
   Dim As jit_uint Ptr args(0 To 1) = {@a, @b}
   jit_function_apply(gcd, @args(0), @result)
   Print Using "gcd(&, &) = &"; a; b; result

   ' clean up libjit
   jit_context_destroy(context)

