[Bug libgcj/51500] [4.7 regression] 106 unexpected libjava testsuite failures with mingw32

["ubizjak at gmail dot com" <gcc-bugzilla@gcc.gnu.org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51500

--- Comment #16 from Uros Bizjak <ubizjak at gmail dot com> 2012-01-30 23:04:54 UTC ---
(In reply to comment #15)

> #define FFI_INIT_TRAMPOLINE_THISCALL(TRAMP,FUN,CTX,SIZE) \
> { unsigned char *__tramp = (unsigned char*)(TRAMP); \
>    unsigned int  __fun = (unsigned int)(FUN); \
>    unsigned int  __ctx = (unsigned int)(CTX); \
>    unsigned int  __dis = __fun - (__ctx + 22);  \
>    *(unsigned int *) &__tramp[0] = 0x8924048b; /* mov (%esp), %eax */ \
>    *(unsigned int *) &__tramp[4] = 0xec83240c; /* mov %ecx, (%esp) */ \
>    *(unsigned int *) &__tramp[8] = 0x24048904; /* sub $4,(%esp) */ \
>                               /* mov %eax, (%esp) */ \
>    *(unsigned char*) &__tramp[12] = 0xb8; \
>    *(unsigned int*)  &__tramp[13] = __ctx; /* movl __ctx, %eax */ \
>    *(unsigned char *)  &__tramp[17] = 0xe8; \
>    *(unsigned int*)  &__tramp[18] = __dis; /* call __fun  */ \
>    *(unsigned int*)  &__tramp[22] = 0x83240c8b; /* mov (%esp), %ecx */ \
>    *(unsigned int*)  &__tramp[26] = 0x0c8904c4; /* add $4, %esp */ \
>    *(unsigned char*) &__tramp[30] = 0x24;    /* mov %ecx, (%esp) */ \
>    *(unsigned short*)  &__tramp[31] = 0xc3; /* ret  */ \
>  }

IMO, you will need to keep 16byte stack alignment at function call, so:

movl (%esp), %eax
movl %ecx, (%esp)
subl $12, %esp
movl %eax, (%esp)
movl __ctx, %eax
call fun
mov (%esp), %ecx
addl $16, %esp
jmp *%ecx