[LLVMdev] Ответ: using dynamic libraries from bytecode?

Yaroslav Kavenchuk kavenchuk at gmail.com
Wed Jun 18 12:27:10 PDT 2008

Mike Stump wrote:
>> Is it possible to use dynamic library (*.so *.dll) from bytecode?
>> If "yes" - how?
> dlopen?  That's be one way.  Also, most systems have shared libraries
> in /usr/lib and these routines are meant to be linked against and
> used.  For example, on darwin, there sinf is resolved from a shared
> library, you declare it and call it, as normal.  You should be able to
> use llvm-gcc to see the bytecode of such a use of a routine from a
> dynamic library.

Thanks! But... small example (mingw):

$ cat gcd_ui.c

#include <stdio.h>
#include <gmp.h>

static void check_ui_range (void)
  mpz_t  x;
  mpz_init_set_ui (x, 111111L);
  mpz_mul_2exp (x, x, 1L);
  mpz_clear (x);

int main() {
  printf("All works!\n");
  return 0;

$ llvm-gcc.exe -I/mingw/include gcd_ui.c -L/mingw/lib -lgmp -o gcd_ui.exe

$ ./gcd_ui.exe
All works!

$ llvm-gcc.exe -I/mingw/include gcd_ui.c -L/mingw/lib -lgmp -o
gcd_ui.ll -emit-llvm -S
llvm-gcc.exe: -lgmp: linker input file unused because linking not done

How determine library for `-emit-llvm` option?

$ cat gcd_ui.ll
; ModuleID = 'gcd_ui.c'
target datalayout =
target triple = "i386-mingw32"
        %struct.__mpz_struct = type { i32, i32, i32* }
@.str = internal constant [11 x i8] c"All works!\00"            ; <[11
x i8]*> [#uses=1]

define internal void @check_ui_range() nounwind  {
        %x = alloca [1 x %struct.__mpz_struct]          ; <[1 x
%struct.__mpz_struct]*> [#uses=4]
        %"alloca point" = bitcast i32 0 to i32          ; <i32> [#uses=0]
        %x1 = bitcast [1 x %struct.__mpz_struct]* %x to
%struct.__mpz_struct*           ; <%struct.__mpz_struct*> [#uses=1]
        call void @__gmpz_init_set_ui( %struct.__mpz_struct* %x1, i32
111111 ) nounwind
        %x2 = bitcast [1 x %struct.__mpz_struct]* %x to
%struct.__mpz_struct*           ; <%struct.__mpz_struct*> [#uses=1]
        %x3 = bitcast [1 x %struct.__mpz_struct]* %x to
%struct.__mpz_struct*           ; <%struct.__mpz_struct*> [#uses=1]
        call void @__gmpz_mul_2exp( %struct.__mpz_struct* %x2,
%struct.__mpz_struct* %x3, i32 1 ) nounwind
        %x4 = bitcast [1 x %struct.__mpz_struct]* %x to
%struct.__mpz_struct*           ; <%struct.__mpz_struct*> [#uses=1]
        call void @__gmpz_clear( %struct.__mpz_struct* %x4 ) nounwind
        br label %return

return:         ; preds = %entry
        ret void

declare dllimport void @__gmpz_init_set_ui(%struct.__mpz_struct*, i32)

declare dllimport void @__gmpz_mul_2exp(%struct.__mpz_struct*,
%struct.__mpz_struct*, i32)

declare dllimport void @__gmpz_clear(%struct.__mpz_struct*)

define i32 @main() nounwind  {
        %retval = alloca i32            ; <i32*> [#uses=2]
        %tmp = alloca i32               ; <i32*> [#uses=2]
        %"alloca point" = bitcast i32 0 to i32          ; <i32> [#uses=0]
        call void @check_ui_range( ) nounwind
        %tmp1 = call i32 @puts( i8* getelementptr ([11 x i8]* @.str,
i32 0, i32 0) ) nounwind           ; <i32> [#uses=0]
        store i32 0, i32* %tmp, align 4
        %tmp2 = load i32* %tmp, align 4         ; <i32> [#uses=1]
        store i32 %tmp2, i32* %retval, align 4
        br label %return

return:         ; preds = %entry
        %retval3 = load i32* %retval            ; <i32> [#uses=1]
        ret i32 %retval3

declare i32 @puts(i8*)

$ llvm-as gcd_ui.ll -o gcd_ui.bc

$ lli gcd_ui.bc
ERROR: Program used external function '__gmpz_init_set_ui' which could
not be resolved!

This application has requested the Runtime to terminate it in an unusual way.
Please contact the application's support team for more information.

How and where I must specify library?

WBR, Yaroslav Kavenchuk.

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