gpointer
mono_arch_get_gsharedvt_trampoline (MonoTrampInfo **info, gboolean aot)
{
guint8 *code, *buf;
int buf_len, cfa_offset;
GSList *unwind_ops = NULL;
MonoJumpInfo *ji = NULL;
guint8 *br_out, *br [16];
int info_offset, mrgctx_offset;
buf_len = 320;
buf = code = mono_global_codeman_reserve (buf_len);
/*
* This trampoline is responsible for marshalling calls between normal code and gsharedvt code. The
* caller is a normal or gshared method which uses the signature of the inflated method to make the call, while
* the callee is a gsharedvt method which has a signature which uses valuetypes in place of type parameters, i.e.
* caller:
* foo<bool> (bool b)
* callee:
* T=<type used to represent vtype type arguments, currently TypedByRef>
* foo<T> (T b)
* The trampoline is responsible for marshalling the arguments and marshalling the result back. To simplify
* things, we create our own stack frame, and do most of the work in a C function, which receives a
* GSharedVtCallInfo structure as an argument. The structure should contain information to execute the C function to
* be as fast as possible. The argument is received in EAX from a gsharedvt trampoline. So the real
* call sequence looks like this:
* caller -> gsharedvt trampoline -> gsharevt in trampoline -> start_gsharedvt_call
* FIXME: Optimize this.
*/
cfa_offset = sizeof (gpointer);
mono_add_unwind_op_def_cfa (unwind_ops, code, buf, X86_ESP, cfa_offset);
mono_add_unwind_op_offset (unwind_ops, code, buf, X86_NREG, -cfa_offset);
x86_push_reg (code, X86_EBP);
cfa_offset += sizeof (gpointer);
mono_add_unwind_op_def_cfa_offset (unwind_ops, code, buf, cfa_offset);
mono_add_unwind_op_offset (unwind_ops, code, buf, X86_EBP, - cfa_offset);
x86_mov_reg_reg (code, X86_EBP, X86_ESP, sizeof (gpointer));
mono_add_unwind_op_def_cfa_reg (unwind_ops, code, buf, X86_EBP);
/* Alloc stack frame/align stack */
x86_alu_reg_imm (code, X86_SUB, X86_ESP, 8);
info_offset = -4;
mrgctx_offset = - 8;
/* The info struct is put into EAX by the gsharedvt trampoline */
/* Save info struct addr */
x86_mov_membase_reg (code, X86_EBP, info_offset, X86_EAX, 4);
/* Save rgctx */
x86_mov_membase_reg (code, X86_EBP, mrgctx_offset, MONO_ARCH_RGCTX_REG, 4);
/* Allocate stack area used to pass arguments to the method */
x86_mov_reg_membase (code, X86_EAX, X86_EAX, MONO_STRUCT_OFFSET (GSharedVtCallInfo, stack_usage), sizeof (gpointer));
x86_alu_reg_reg (code, X86_SUB, X86_ESP, X86_EAX);
#if 0
/* Stack alignment check */
x86_mov_reg_reg (code, X86_ECX, X86_ESP, 4);
x86_alu_reg_imm (code, X86_AND, X86_ECX, MONO_ARCH_FRAME_ALIGNMENT - 1);
x86_alu_reg_imm (code, X86_CMP, X86_ECX, 0);
x86_branch_disp (code, X86_CC_EQ, 3, FALSE);
x86_breakpoint (code);
#endif
/* ecx = caller argument area */
x86_mov_reg_reg (code, X86_ECX, X86_EBP, 4);
x86_alu_reg_imm (code, X86_ADD, X86_ECX, 8);
/* eax = callee argument area */
x86_mov_reg_reg (code, X86_EAX, X86_ESP, 4);
/* Call start_gsharedvt_call */
/* Arg 4 */
x86_push_membase (code, X86_EBP, mrgctx_offset);
/* Arg3 */
x86_push_reg (code, X86_EAX);
/* Arg2 */
x86_push_reg (code, X86_ECX);
/* Arg1 */
x86_push_membase (code, X86_EBP, info_offset);
if (aot) {
code = mono_arch_emit_load_aotconst (buf, code, &ji, MONO_PATCH_INFO_JIT_ICALL_ADDR, "mono_x86_start_gsharedvt_call");
x86_call_reg (code, X86_EAX);
} else {
x86_call_code (code, mono_x86_start_gsharedvt_call);
}
x86_alu_reg_imm (code, X86_ADD, X86_ESP, 4 * 4);
/* The address to call is in eax */
/* The stack is now setup for the real call */
/* Load info struct */
x86_mov_reg_membase (code, X86_ECX, X86_EBP, info_offset, 4);
/* Load rgctx */
x86_mov_reg_membase (code, MONO_ARCH_RGCTX_REG, X86_EBP, mrgctx_offset, sizeof (gpointer));
/* Make the call */
x86_call_reg (code, X86_EAX);
/* The return value is either in registers, or stored to an area beginning at sp [info->vret_slot] */
/* EAX/EDX might contain the return value, only ECX is free */
/* Load info struct */
x86_mov_reg_membase (code, X86_ECX, X86_EBP, info_offset, 4);
/* Branch to the in/out handling code */
x86_alu_membase_imm (code, X86_CMP, X86_ECX, MONO_STRUCT_OFFSET (GSharedVtCallInfo, gsharedvt_in), 1);
br_out = code;
x86_branch32 (code, X86_CC_NE, 0, TRUE);
/*
* IN CASE
*/
/* Load ret marshal type */
x86_mov_reg_membase (code, X86_ECX, X86_ECX, MONO_STRUCT_OFFSET (GSharedVtCallInfo, ret_marshal), 4);
x86_alu_reg_imm (code, X86_CMP, X86_ECX, GSHAREDVT_RET_NONE);
br [0] = code;
x86_branch8 (code, X86_CC_NE, 0, TRUE);
/* Normal return, no marshalling required */
x86_leave (code);
x86_ret (code);
/* Return value marshalling */
x86_patch (br [0], code);
/* Load info struct */
x86_mov_reg_membase (code, X86_EAX, X86_EBP, info_offset, 4);
/* Load 'vret_slot' */
x86_mov_reg_membase (code, X86_EAX, X86_EAX, MONO_STRUCT_OFFSET (GSharedVtCallInfo, vret_slot), 4);
/* Compute ret area address */
x86_shift_reg_imm (code, X86_SHL, X86_EAX, 2);
x86_alu_reg_reg (code, X86_ADD, X86_EAX, X86_ESP);
/* The callee does a ret $4, so sp is off by 4 */
x86_alu_reg_imm (code, X86_SUB, X86_EAX, sizeof (gpointer));
/* Branch to specific marshalling code */
// FIXME: Move the I4 case to the top */
x86_alu_reg_imm (code, X86_CMP, X86_ECX, GSHAREDVT_RET_DOUBLE_FPSTACK);
br [1] = code;
x86_branch8 (code, X86_CC_E, 0, TRUE);
x86_alu_reg_imm (code, X86_CMP, X86_ECX, GSHAREDVT_RET_FLOAT_FPSTACK);
br [2] = code;
x86_branch8 (code, X86_CC_E, 0, TRUE);
x86_alu_reg_imm (code, X86_CMP, X86_ECX, GSHAREDVT_RET_STACK_POP);
br [3] = code;
x86_branch8 (code, X86_CC_E, 0, TRUE);
x86_alu_reg_imm (code, X86_CMP, X86_ECX, GSHAREDVT_RET_I1);
br [4] = code;
x86_branch8 (code, X86_CC_E, 0, TRUE);
x86_alu_reg_imm (code, X86_CMP, X86_ECX, GSHAREDVT_RET_U1);
br [5] = code;
x86_branch8 (code, X86_CC_E, 0, TRUE);
x86_alu_reg_imm (code, X86_CMP, X86_ECX, GSHAREDVT_RET_I2);
br [6] = code;
x86_branch8 (code, X86_CC_E, 0, TRUE);
x86_alu_reg_imm (code, X86_CMP, X86_ECX, GSHAREDVT_RET_U2);
br [7] = code;
x86_branch8 (code, X86_CC_E, 0, TRUE);
/* IREGS case */
/* Load both eax and edx for simplicity */
x86_mov_reg_membase (code, X86_EDX, X86_EAX, sizeof (gpointer), sizeof (gpointer));
x86_mov_reg_membase (code, X86_EAX, X86_EAX, 0, sizeof (gpointer));
x86_leave (code);
x86_ret (code);
/* DOUBLE_FPSTACK case */
x86_patch (br [1], code);
x86_fld_membase (code, X86_EAX, 0, TRUE);
x86_jump8 (code, 0);
x86_leave (code);
x86_ret (code);
/* FLOAT_FPSTACK case */
x86_patch (br [2], code);
x86_fld_membase (code, X86_EAX, 0, FALSE);
x86_leave (code);
x86_ret (code);
/* STACK_POP case */
x86_patch (br [3], code);
x86_leave (code);
x86_ret_imm (code, 4);
/* I1 case */
x86_patch (br [4], code);
x86_widen_membase (code, X86_EAX, X86_EAX, 0, TRUE, FALSE);
x86_leave (code);
x86_ret (code);
/* U1 case */
x86_patch (br [5], code);
x86_widen_membase (code, X86_EAX, X86_EAX, 0, FALSE, FALSE);
x86_leave (code);
x86_ret (code);
/* I2 case */
x86_patch (br [6], code);
x86_widen_membase (code, X86_EAX, X86_EAX, 0, TRUE, TRUE);
x86_leave (code);
x86_ret (code);
/* U2 case */
x86_patch (br [7], code);
x86_widen_membase (code, X86_EAX, X86_EAX, 0, FALSE, TRUE);
x86_leave (code);
x86_ret (code);
/*
* OUT CASE
*/
x86_patch (br_out, code);
/* Load ret marshal type into ECX */
x86_mov_reg_membase (code, X86_ECX, X86_ECX, MONO_STRUCT_OFFSET (GSharedVtCallInfo, ret_marshal), 4);
x86_alu_reg_imm (code, X86_CMP, X86_ECX, GSHAREDVT_RET_NONE);
br [0] = code;
x86_branch8 (code, X86_CC_NE, 0, TRUE);
/* Normal return, no marshalling required */
x86_leave (code);
x86_ret (code);
/* Return value marshalling */
x86_patch (br [0], code);
/* EAX might contain the return value */
// FIXME: Use moves
x86_push_reg (code, X86_EAX);
/* Load info struct */
x86_mov_reg_membase (code, X86_EAX, X86_EBP, info_offset, 4);
/* Load 'vret_arg_slot' */
x86_mov_reg_membase (code, X86_EAX, X86_EAX, MONO_STRUCT_OFFSET (GSharedVtCallInfo, vret_arg_slot), 4);
/* Compute ret area address in the caller frame in EAX */
x86_shift_reg_imm (code, X86_SHL, X86_EAX, 2);
x86_alu_reg_reg (code, X86_ADD, X86_EAX, X86_EBP);
x86_alu_reg_imm (code, X86_ADD, X86_EAX, 8);
x86_mov_reg_membase (code, X86_EAX, X86_EAX, 0, sizeof (gpointer));
/* Branch to specific marshalling code */
x86_alu_reg_imm (code, X86_CMP, X86_ECX, GSHAREDVT_RET_DOUBLE_FPSTACK);
br [1] = code;
x86_branch8 (code, X86_CC_E, 0, TRUE);
x86_alu_reg_imm (code, X86_CMP, X86_ECX, GSHAREDVT_RET_FLOAT_FPSTACK);
br [2] = code;
x86_branch8 (code, X86_CC_E, 0, TRUE);
x86_alu_reg_imm (code, X86_CMP, X86_ECX, GSHAREDVT_RET_STACK_POP);
br [3] = code;
x86_branch8 (code, X86_CC_E, 0, TRUE);
x86_alu_reg_imm (code, X86_CMP, X86_ECX, GSHAREDVT_RET_IREGS);
br [4] = code;
x86_branch8 (code, X86_CC_E, 0, TRUE);
/* IREG case */
x86_mov_reg_reg (code, X86_ECX, X86_EAX, sizeof (gpointer));
x86_pop_reg (code, X86_EAX);
x86_mov_membase_reg (code, X86_ECX, 0, X86_EAX, sizeof (gpointer));
x86_leave (code);
x86_ret_imm (code, 4);
/* IREGS case */
x86_patch (br [4], code);
x86_mov_reg_reg (code, X86_ECX, X86_EAX, sizeof (gpointer));
x86_pop_reg (code, X86_EAX);
x86_mov_membase_reg (code, X86_ECX, sizeof (gpointer), X86_EDX, sizeof (gpointer));
x86_mov_membase_reg (code, X86_ECX, 0, X86_EAX, sizeof (gpointer));
x86_leave (code);
x86_ret_imm (code, 4);
/* DOUBLE_FPSTACK case */
x86_alu_reg_imm (code, X86_ADD, X86_ESP, 4);
x86_patch (br [1], code);
x86_fst_membase (code, X86_EAX, 0, TRUE, TRUE);
x86_jump8 (code, 0);
x86_leave (code);
x86_ret_imm (code, 4);
/* FLOAT_FPSTACK case */
x86_alu_reg_imm (code, X86_ADD, X86_ESP, 4);
x86_patch (br [2], code);
x86_fst_membase (code, X86_EAX, 0, FALSE, TRUE);
x86_leave (code);
x86_ret_imm (code, 4);
/* STACK_POP case */
x86_patch (br [3], code);
x86_leave (code);
x86_ret_imm (code, 4);
g_assert ((code - buf) < buf_len);
if (info)
*info = mono_tramp_info_create ("gsharedvt_trampoline", buf, code - buf, ji, unwind_ops);
mono_arch_flush_icache (buf, code - buf);
return buf;
}
void _jit_gen_epilog(jit_gencode_t gen, jit_function_t func)
{
jit_nint pop_bytes = 0;
int reg, offset;
unsigned char *inst;
int struct_return_offset = 0;
void **fixup;
void **next;
/* Check if there is sufficient space for the epilog */
_jit_cache_check_space(&gen->posn, 48);
#if JIT_APPLY_X86_FASTCALL == 1
/* Determine the number of parameter bytes to pop when we return */
{
jit_type_t signature;
unsigned int num_params;
unsigned int param;
signature = func->signature;
if(jit_type_get_abi(signature) == jit_abi_stdcall ||
jit_type_get_abi(signature) == jit_abi_thiscall||
jit_type_get_abi(signature) == jit_abi_fastcall)
{
if(func->nested_parent)
{
pop_bytes += sizeof(void *);
}
if(jit_type_return_via_pointer(jit_type_get_return(signature)))
{
struct_return_offset = 2 * sizeof(void *) + pop_bytes;
pop_bytes += sizeof(void *);
}
num_params = jit_type_num_params(signature);
for(param = 0; param < num_params; ++param)
{
pop_bytes += ROUND_STACK
(jit_type_get_size
(jit_type_get_param(signature, param)));
}
if(jit_type_get_abi(signature) == jit_abi_fastcall)
{
/* The first two words are in fastcall registers */
if(pop_bytes > (2 * sizeof(void *)))
{
pop_bytes -= 2 * sizeof(void *);
}
else
{
pop_bytes = 0;
}
struct_return_offset = 0;
}
else if(jit_type_get_abi(signature) == jit_abi_thiscall)
{
/* The this is in ECX register */
if(pop_bytes > (1 * sizeof(void *)))
{
pop_bytes -= 1 * sizeof(void *);
}
else
{
pop_bytes = 0;
}
struct_return_offset = 0;
}
}
else if(!(func->nested_parent) &&
jit_type_return_via_pointer(jit_type_get_return(signature)))
{
#if JIT_APPLY_X86_POP_STRUCT_RETURN == 1
pop_bytes += sizeof(void *);
#endif
struct_return_offset = 2 * sizeof(void *);
}
}
#else
{
/* We only need to pop structure pointers in non-nested functions */
jit_type_t signature;
signature = func->signature;
if(!(func->nested_parent) &&
jit_type_return_via_pointer(jit_type_get_return(signature)))
{
#if JIT_APPLY_X86_POP_STRUCT_RETURN == 1
pop_bytes += sizeof(void *);
#endif
struct_return_offset = 2 * sizeof(void *);
}
}
#endif
/* Perform fixups on any blocks that jump to the epilog */
inst = gen->posn.ptr;
fixup = (void **)(gen->epilog_fixup);
while(fixup != 0)
{
next = (void **)(fixup[0]);
fixup[0] = (void *)(((jit_nint)inst) - ((jit_nint)fixup) - 4);
fixup = next;
}
gen->epilog_fixup = 0;
/* If we are returning a structure via a pointer, then copy
the pointer value into EAX when we return */
if(struct_return_offset != 0)
{
x86_mov_reg_membase(inst, X86_EAX, X86_EBP, struct_return_offset, 4);
}
/* Restore the callee save registers that we used */
if(gen->stack_changed)
{
offset = -(func->builder->frame_size);
for(reg = 0; reg <= 7; ++reg)
{
if(jit_reg_is_used(gen->touched, reg) &&
(_jit_reg_info[reg].flags & JIT_REG_CALL_USED) == 0)
{
offset -= sizeof(void *);
x86_mov_reg_membase(inst, _jit_reg_info[reg].cpu_reg,
X86_EBP, offset, sizeof(void *));
}
}
}
else
{
for(reg = 7; reg >= 0; --reg)
{
if(jit_reg_is_used(gen->touched, reg) &&
(_jit_reg_info[reg].flags & JIT_REG_CALL_USED) == 0)
{
x86_pop_reg(inst, _jit_reg_info[reg].cpu_reg);
}
}
}
/* Pop the stack frame and restore the saved copy of ebp */
if(gen->stack_changed || func->builder->frame_size > 0)
{
x86_mov_reg_reg(inst, X86_ESP, X86_EBP, sizeof(void *));
}
x86_pop_reg(inst, X86_EBP);
/* Return from the current function */
if(pop_bytes > 0)
{
x86_ret_imm(inst, pop_bytes);
}
else
{
x86_ret(inst);
}
gen->posn.ptr = inst;
}
