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;
}
guchar*
mono_arch_create_generic_trampoline (MonoTrampolineType tramp_type, MonoTrampInfo **info, gboolean aot)
{
const char *tramp_name;
guint8 *buf, *code, *tramp, *br_ex_check;
GSList *unwind_ops = NULL;
MonoJumpInfo *ji = NULL;
int i, offset, frame_size, regarray_offset, lmf_offset, caller_ip_offset, arg_offset;
int cfa_offset; /* cfa = cfa_reg + cfa_offset */
code = buf = mono_global_codeman_reserve (256);
/* Note that there is a single argument to the trampoline
* and it is stored at: esp + pushed_args * sizeof (target_mgreg_t)
* the ret address is at: esp + (pushed_args + 1) * sizeof (target_mgreg_t)
*/
/* Compute frame offsets relative to the frame pointer %ebp */
arg_offset = sizeof (target_mgreg_t);
caller_ip_offset = 2 * sizeof (target_mgreg_t);
offset = 0;
offset += sizeof (MonoLMF);
lmf_offset = -offset;
offset += X86_NREG * sizeof (target_mgreg_t);
regarray_offset = -offset;
/* Argument area */
offset += 4 * sizeof (target_mgreg_t);
frame_size = ALIGN_TO (offset, MONO_ARCH_FRAME_ALIGNMENT);
/* ret addr and arg are on the stack */
cfa_offset = 2 * sizeof (target_mgreg_t);
mono_add_unwind_op_def_cfa (unwind_ops, code, buf, X86_ESP, cfa_offset);
// IP saved at CFA - 4
mono_add_unwind_op_offset (unwind_ops, code, buf, X86_NREG, -4);
/* Allocate frame */
x86_push_reg (code, X86_EBP);
cfa_offset += sizeof (target_mgreg_t);
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);
mono_add_unwind_op_def_cfa_reg (unwind_ops, code, buf, X86_EBP);
/* There are three words on the stack, adding + 4 aligns the stack to 16, which is needed on osx */
x86_alu_reg_imm (code, X86_SUB, X86_ESP, frame_size + sizeof (target_mgreg_t));
/* Save all registers */
for (i = X86_EAX; i <= X86_EDI; ++i) {
int reg = i;
if (i == X86_EBP) {
/* Save original ebp */
/* EAX is already saved */
x86_mov_reg_membase (code, X86_EAX, X86_EBP, 0, sizeof (target_mgreg_t));
reg = X86_EAX;
} else if (i == X86_ESP) {
/* Save original esp */
/* EAX is already saved */
x86_mov_reg_reg (code, X86_EAX, X86_EBP);
/* Saved ebp + trampoline arg + return addr */
x86_alu_reg_imm (code, X86_ADD, X86_EAX, 3 * sizeof (target_mgreg_t));
reg = X86_EAX;
}
x86_mov_membase_reg (code, X86_EBP, regarray_offset + (i * sizeof (target_mgreg_t)), reg, sizeof (target_mgreg_t));
}
/* Setup LMF */
/* eip */
if (tramp_type == MONO_TRAMPOLINE_JUMP) {
x86_mov_membase_imm (code, X86_EBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, eip), 0, sizeof (target_mgreg_t));
} else {
x86_mov_reg_membase (code, X86_EAX, X86_EBP, caller_ip_offset, sizeof (target_mgreg_t));
x86_mov_membase_reg (code, X86_EBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, eip), X86_EAX, sizeof (target_mgreg_t));
}
/* method */
if ((tramp_type == MONO_TRAMPOLINE_JIT) || (tramp_type == MONO_TRAMPOLINE_JUMP)) {
x86_mov_reg_membase (code, X86_EAX, X86_EBP, arg_offset, sizeof (target_mgreg_t));
x86_mov_membase_reg (code, X86_EBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, method), X86_EAX, sizeof (target_mgreg_t));
} else {
x86_mov_membase_imm (code, X86_EBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, method), 0, sizeof (target_mgreg_t));
}
/* esp */
x86_mov_reg_membase (code, X86_EAX, X86_EBP, regarray_offset + (X86_ESP * sizeof (target_mgreg_t)), sizeof (target_mgreg_t));
x86_mov_membase_reg (code, X86_EBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, esp), X86_EAX, sizeof (target_mgreg_t));
/* callee save registers */
x86_mov_reg_membase (code, X86_EAX, X86_EBP, regarray_offset + (X86_EBX * sizeof (target_mgreg_t)), sizeof (target_mgreg_t));
x86_mov_membase_reg (code, X86_EBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, ebx), X86_EAX, sizeof (target_mgreg_t));
x86_mov_reg_membase (code, X86_EAX, X86_EBP, regarray_offset + (X86_EDI * sizeof (target_mgreg_t)), sizeof (target_mgreg_t));
x86_mov_membase_reg (code, X86_EBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, edi), X86_EAX, sizeof (target_mgreg_t));
x86_mov_reg_membase (code, X86_EAX, X86_EBP, regarray_offset + (X86_ESI * sizeof (target_mgreg_t)), sizeof (target_mgreg_t));
x86_mov_membase_reg (code, X86_EBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, esi), X86_EAX, sizeof (target_mgreg_t));
x86_mov_reg_membase (code, X86_EAX, X86_EBP, regarray_offset + (X86_EBP * sizeof (target_mgreg_t)), sizeof (target_mgreg_t));
x86_mov_membase_reg (code, X86_EBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, ebp), X86_EAX, sizeof (target_mgreg_t));
/* Push LMF */
/* get the address of lmf for the current thread */
if (aot) {
code = mono_arch_emit_load_aotconst (buf, code, &ji, MONO_PATCH_INFO_JIT_ICALL_ADDR, "mono_get_lmf_addr");
x86_call_reg (code, X86_EAX);
} else {
x86_call_code (code, mono_get_lmf_addr);
}
/* lmf->lmf_addr = lmf_addr (%eax) */
x86_mov_membase_reg (code, X86_EBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, lmf_addr), X86_EAX, sizeof (target_mgreg_t));
/* lmf->previous_lmf = *(lmf_addr) */
x86_mov_reg_membase (code, X86_ECX, X86_EAX, 0, sizeof (target_mgreg_t));
/* Signal to mono_arch_unwind_frame () that this is a trampoline frame */
x86_alu_reg_imm (code, X86_ADD, X86_ECX, 1);
x86_mov_membase_reg (code, X86_EBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, previous_lmf), X86_ECX, sizeof (target_mgreg_t));
/* *lmf_addr = lmf */
x86_lea_membase (code, X86_ECX, X86_EBP, lmf_offset);
x86_mov_membase_reg (code, X86_EAX, 0, X86_ECX, sizeof (target_mgreg_t));
/* Call trampoline function */
/* Arg 1 - registers */
x86_lea_membase (code, X86_EAX, X86_EBP, regarray_offset);
x86_mov_membase_reg (code, X86_ESP, (0 * sizeof (target_mgreg_t)), X86_EAX, sizeof (target_mgreg_t));
/* Arg2 - calling code */
if (tramp_type == MONO_TRAMPOLINE_JUMP) {
x86_mov_membase_imm (code, X86_ESP, (1 * sizeof (target_mgreg_t)), 0, sizeof (target_mgreg_t));
} else {
x86_mov_reg_membase (code, X86_EAX, X86_EBP, caller_ip_offset, sizeof (target_mgreg_t));
x86_mov_membase_reg (code, X86_ESP, (1 * sizeof (target_mgreg_t)), X86_EAX, sizeof (target_mgreg_t));
}
/* Arg3 - trampoline argument */
x86_mov_reg_membase (code, X86_EAX, X86_EBP, arg_offset, sizeof (target_mgreg_t));
x86_mov_membase_reg (code, X86_ESP, (2 * sizeof (target_mgreg_t)), X86_EAX, sizeof (target_mgreg_t));
/* Arg4 - trampoline address */
// FIXME:
x86_mov_membase_imm (code, X86_ESP, (3 * sizeof (target_mgreg_t)), 0, sizeof (target_mgreg_t));
#ifdef __APPLE__
/* check the stack is aligned after the ret ip is pushed */
/*
x86_mov_reg_reg (code, X86_EDX, X86_ESP);
x86_alu_reg_imm (code, X86_AND, X86_EDX, 15);
x86_alu_reg_imm (code, X86_CMP, X86_EDX, 0);
x86_branch_disp (code, X86_CC_Z, 3, FALSE);
x86_breakpoint (code);
*/
#endif
if (aot) {
code = mono_arch_emit_load_aotconst (buf, code, &ji, MONO_PATCH_INFO_TRAMPOLINE_FUNC_ADDR, GINT_TO_POINTER (tramp_type));
x86_call_reg (code, X86_EAX);
} else {
tramp = (guint8*)mono_get_trampoline_func (tramp_type);
x86_call_code (code, tramp);
}
/*
* Overwrite the trampoline argument with the address we need to jump to,
* to free %eax.
*/
x86_mov_membase_reg (code, X86_EBP, arg_offset, X86_EAX, 4);
/* Restore LMF */
x86_mov_reg_membase (code, X86_EAX, X86_EBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, lmf_addr), sizeof (target_mgreg_t));
x86_mov_reg_membase (code, X86_ECX, X86_EBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, previous_lmf), sizeof (target_mgreg_t));
x86_alu_reg_imm (code, X86_SUB, X86_ECX, 1);
x86_mov_membase_reg (code, X86_EAX, 0, X86_ECX, sizeof (target_mgreg_t));
/* Check for interruptions */
if (aot) {
code = mono_arch_emit_load_aotconst (buf, code, &ji, MONO_PATCH_INFO_JIT_ICALL_ADDR, "mono_thread_force_interruption_checkpoint_noraise");
x86_call_reg (code, X86_EAX);
} else {
x86_call_code (code, (guint8*)mono_thread_force_interruption_checkpoint_noraise);
}
x86_test_reg_reg (code, X86_EAX, X86_EAX);
br_ex_check = code;
x86_branch8 (code, X86_CC_Z, -1, 1);
/*
* Exception case:
* We have an exception we want to throw in the caller's frame, so pop
* the trampoline frame and throw from the caller.
*/
x86_leave (code);
/*
* The exception is in eax.
* We are calling the throw trampoline used by OP_THROW, so we have to setup the
* stack to look the same.
* The stack contains the ret addr, and the trampoline argument, the throw trampoline
* expects it to contain the ret addr and the exception. It also needs to be aligned
* after the exception is pushed.
*/
/* Align stack */
x86_push_reg (code, X86_EAX);
/* Push the exception */
x86_push_reg (code, X86_EAX);
//x86_breakpoint (code);
/* Push the original return value */
x86_push_membase (code, X86_ESP, 3 * 4);
/*
* EH is initialized after trampolines, so get the address of the variable
* which contains throw_exception, and load it from there.
*/
if (aot) {
/* Not really a jit icall */
code = mono_arch_emit_load_aotconst (buf, code, &ji, MONO_PATCH_INFO_JIT_ICALL_ADDR, "rethrow_preserve_exception_addr");
} else {
x86_mov_reg_imm (code, X86_ECX, (guint8*)mono_get_rethrow_preserve_exception_addr ());
}
x86_mov_reg_membase (code, X86_ECX, X86_ECX, 0, sizeof (target_mgreg_t));
x86_jump_reg (code, X86_ECX);
/* Normal case */
mono_x86_patch (br_ex_check, code);
/* Restore registers */
for (i = X86_EAX; i <= X86_EDI; ++i) {
if (i == X86_ESP || i == X86_EBP)
continue;
if (i == X86_EAX && tramp_type != MONO_TRAMPOLINE_AOT_PLT)
continue;
x86_mov_reg_membase (code, i, X86_EBP, regarray_offset + (i * 4), 4);
}
/* Restore frame */
x86_leave (code);
cfa_offset -= sizeof (target_mgreg_t);
mono_add_unwind_op_def_cfa (unwind_ops, code, buf, X86_ESP, cfa_offset);
mono_add_unwind_op_same_value (unwind_ops, code, buf, X86_EBP);
if (MONO_TRAMPOLINE_TYPE_MUST_RETURN (tramp_type)) {
/* Load the value returned by the trampoline */
x86_mov_reg_membase (code, X86_EAX, X86_ESP, 0, 4);
/* The trampoline returns normally, pop the trampoline argument */
x86_alu_reg_imm (code, X86_ADD, X86_ESP, 4);
cfa_offset -= sizeof (target_mgreg_t);
mono_add_unwind_op_def_cfa_offset (unwind_ops, code, buf, cfa_offset);
x86_ret (code);
} else {
x86_ret (code);
}
g_assert ((code - buf) <= 256);
MONO_PROFILER_RAISE (jit_code_buffer, (buf, code - buf, MONO_PROFILER_CODE_BUFFER_HELPER, NULL));
tramp_name = mono_get_generic_trampoline_name (tramp_type);
*info = mono_tramp_info_create (tramp_name, buf, code - buf, ji, unwind_ops);
return buf;
}
