/*
* mono_arch_get_restore_context:
*
* Returns a pointer to a method which restores a previously saved sigcontext.
*/
gpointer
mono_arch_get_restore_context (MonoTrampInfo **info, gboolean aot)
{
guint8 *start = NULL;
guint8 *code;
MonoJumpInfo *ji = NULL;
GSList *unwind_ops = NULL;
/* restore_contect (MonoContext *ctx) */
start = code = mono_global_codeman_reserve (128);
/* load ctx */
x86_mov_reg_membase (code, X86_EAX, X86_ESP, 4, 4);
/* restore EBX */
x86_mov_reg_membase (code, X86_EBX, X86_EAX, MONO_STRUCT_OFFSET (MonoContext, ebx), 4);
/* restore EDI */
x86_mov_reg_membase (code, X86_EDI, X86_EAX, MONO_STRUCT_OFFSET (MonoContext, edi), 4);
/* restore ESI */
x86_mov_reg_membase (code, X86_ESI, X86_EAX, MONO_STRUCT_OFFSET (MonoContext, esi), 4);
/* restore EDX */
x86_mov_reg_membase (code, X86_EDX, X86_EAX, MONO_STRUCT_OFFSET (MonoContext, edx), 4);
/*
* The context resides on the stack, in the stack frame of the
* caller of this function. The stack pointer that we need to
* restore is potentially many stack frames higher up, so the
* distance between them can easily be more than the red zone
* size. Hence the stack pointer can be restored only after
* we have finished loading everything from the context.
*/
/* load ESP into EBP */
x86_mov_reg_membase (code, X86_EBP, X86_EAX, MONO_STRUCT_OFFSET (MonoContext, esp), 4);
/* load return address into ECX */
x86_mov_reg_membase (code, X86_ECX, X86_EAX, MONO_STRUCT_OFFSET (MonoContext, eip), 4);
/* save the return addr to the restored stack - 4 */
x86_mov_membase_reg (code, X86_EBP, -4, X86_ECX, 4);
/* load EBP into ECX */
x86_mov_reg_membase (code, X86_ECX, X86_EAX, MONO_STRUCT_OFFSET (MonoContext, ebp), 4);
/* save EBP to the restored stack - 8 */
x86_mov_membase_reg (code, X86_EBP, -8, X86_ECX, 4);
/* load EAX into ECX */
x86_mov_reg_membase (code, X86_ECX, X86_EAX, MONO_STRUCT_OFFSET (MonoContext, eax), 4);
/* save EAX to the restored stack - 12 */
x86_mov_membase_reg (code, X86_EBP, -12, X86_ECX, 4);
/* restore ECX */
x86_mov_reg_membase (code, X86_ECX, X86_EAX, MONO_STRUCT_OFFSET (MonoContext, ecx), 4);
/* restore ESP - 12 */
x86_lea_membase (code, X86_ESP, X86_EBP, -12);
/* restore EAX */
x86_pop_reg (code, X86_EAX);
/* restore EBP */
x86_pop_reg (code, X86_EBP);
/* jump to the saved IP */
x86_ret (code);
if (info)
*info = mono_tramp_info_create ("restore_context", start, code - start, ji, unwind_ops);
else {
GSList *l;
for (l = unwind_ops; l; l = l->next)
g_free (l->data);
g_slist_free (unwind_ops);
}
mono_arch_flush_icache (start, code - start);
mono_profiler_code_buffer_new (start, code - start, MONO_PROFILER_CODE_BUFFER_EXCEPTION_HANDLING, NULL);
return start;
}
/*
* get_throw_trampoline:
*
* Generate a call to mono_x86_throw_exception/
* mono_x86_throw_corlib_exception.
* If LLVM is true, generate code which assumes the caller is LLVM generated code,
* which doesn't push the arguments.
*/
static guint8*
get_throw_trampoline (const char *name, gboolean rethrow, gboolean llvm, gboolean corlib, gboolean llvm_abs, gboolean resume_unwind, MonoTrampInfo **info, gboolean aot)
{
guint8 *start, *code, *labels [16];
int i, stack_size, stack_offset, arg_offsets [5], regs_offset;
MonoJumpInfo *ji = NULL;
GSList *unwind_ops = NULL;
guint kMaxCodeSize = 192;
start = code = mono_global_codeman_reserve (kMaxCodeSize);
stack_size = 128;
/*
* On apple, the stack is misaligned by the pushing of the return address.
*/
if (!llvm && corlib)
/* On OSX, we don't generate alignment code to save space */
stack_size += 4;
else
stack_size += MONO_ARCH_FRAME_ALIGNMENT - 4;
/*
* The stack looks like this:
* <pc offset> (only if corlib is TRUE)
* <exception object>/<type token>
* <return addr> <- esp (unaligned on apple)
*/
unwind_ops = mono_arch_get_cie_program ();
/* Alloc frame */
x86_alu_reg_imm (code, X86_SUB, X86_ESP, stack_size);
mono_add_unwind_op_def_cfa_offset (unwind_ops, code, start, stack_size + 4);
arg_offsets [0] = 0;
arg_offsets [1] = 4;
arg_offsets [2] = 8;
arg_offsets [3] = 12;
regs_offset = 16;
/* Save registers */
for (i = 0; i < X86_NREG; ++i)
if (i != X86_ESP)
x86_mov_membase_reg (code, X86_ESP, regs_offset + (i * 4), i, 4);
/* Calculate the offset between the current sp and the sp of the caller */
if (llvm) {
/* LLVM doesn't push the arguments */
stack_offset = stack_size + 4;
} else {
if (corlib) {
/* Two arguments */
stack_offset = stack_size + 4 + 8;
#ifdef __APPLE__
/* We don't generate stack alignment code on osx to save space */
#endif
} else {
/* One argument + stack alignment */
stack_offset = stack_size + 4 + 4;
#ifdef __APPLE__
/* Pop the alignment added by OP_THROW too */
stack_offset += MONO_ARCH_FRAME_ALIGNMENT - 4;
#else
if (mono_do_x86_stack_align)
stack_offset += MONO_ARCH_FRAME_ALIGNMENT - 4;
#endif
}
}
/* Save ESP */
x86_lea_membase (code, X86_EAX, X86_ESP, stack_offset);
x86_mov_membase_reg (code, X86_ESP, regs_offset + (X86_ESP * 4), X86_EAX, 4);
/* Clear fp stack */
labels [0] = code;
x86_fnstsw (code);
x86_shift_reg_imm (code, X86_SHR, X86_EAX, 11);
x86_alu_reg_imm (code, X86_AND, X86_EAX, 7);
x86_alu_reg_imm (code, X86_CMP, X86_EAX, 0);
labels [1] = code;
x86_branch8 (code, X86_CC_EQ, 0, FALSE);
x86_fstp (code, 0);
x86_jump_code (code, labels [0]);
mono_x86_patch (labels [1], code);
/* Set arg1 == regs */
x86_lea_membase (code, X86_EAX, X86_ESP, regs_offset);
x86_mov_membase_reg (code, X86_ESP, arg_offsets [0], X86_EAX, 4);
/* Set arg2 == exc/ex_token_index */
if (resume_unwind)
x86_mov_reg_imm (code, X86_EAX, 0);
else
x86_mov_reg_membase (code, X86_EAX, X86_ESP, stack_size + 4, 4);
x86_mov_membase_reg (code, X86_ESP, arg_offsets [1], X86_EAX, 4);
/* Set arg3 == eip */
if (llvm_abs)
x86_alu_reg_reg (code, X86_XOR, X86_EAX, X86_EAX);
else
x86_mov_reg_membase (code, X86_EAX, X86_ESP, stack_size, 4);
x86_mov_membase_reg (code, X86_ESP, arg_offsets [2], X86_EAX, 4);
/* Set arg4 == rethrow/pc_offset */
if (resume_unwind) {
x86_mov_membase_imm (code, X86_ESP, arg_offsets [3], 0, 4);
} else if (corlib) {
x86_mov_reg_membase (code, X86_EAX, X86_ESP, stack_size + 8, 4);
if (llvm_abs) {
/*
* The caller is LLVM code which passes the absolute address not a pc offset,
* so compensate by passing 0 as 'ip' and passing the negated abs address as
* the pc offset.
*/
x86_neg_reg (code, X86_EAX);
}
x86_mov_membase_reg (code, X86_ESP, arg_offsets [3], X86_EAX, 4);
} else {
x86_mov_membase_imm (code, X86_ESP, arg_offsets [3], rethrow, 4);
}
/* Make the call */
if (aot) {
// This can be called from runtime code, which can't guarantee that
// ebx contains the got address.
// So emit the got address loading code too
code = mono_arch_emit_load_got_addr (start, code, NULL, &ji);
code = mono_arch_emit_load_aotconst (start, code, &ji, MONO_PATCH_INFO_JIT_ICALL_ADDR, corlib ? "mono_x86_throw_corlib_exception" : "mono_x86_throw_exception");
x86_call_reg (code, X86_EAX);
} else {
x86_call_code (code, resume_unwind ? (gpointer)(mono_x86_resume_unwind) : (corlib ? (gpointer)mono_x86_throw_corlib_exception : (gpointer)mono_x86_throw_exception));
}
x86_breakpoint (code);
g_assert ((code - start) < kMaxCodeSize);
if (info)
*info = mono_tramp_info_create (name, start, code - start, ji, unwind_ops);
else {
GSList *l;
for (l = unwind_ops; l; l = l->next)
g_free (l->data);
g_slist_free (unwind_ops);
}
mono_arch_flush_icache (start, code - start);
mono_profiler_code_buffer_new (start, code - start, MONO_PROFILER_CODE_BUFFER_EXCEPTION_HANDLING, NULL);
return start;
}
/*
* mono_arch_create_sdb_trampoline:
*
* Return a trampoline which captures the current context, passes it to
* mini_get_dbg_callbacks ()->single_step_from_context ()/mini_get_dbg_callbacks ()->breakpoint_from_context (),
* then restores the (potentially changed) context.
*/
guint8*
mono_arch_create_sdb_trampoline (gboolean single_step, MonoTrampInfo **info, gboolean aot)
{
int tramp_size = 256;
int framesize, ctx_offset, cfa_offset;
guint8 *code, *buf;
GSList *unwind_ops = NULL;
MonoJumpInfo *ji = NULL;
code = buf = mono_global_codeman_reserve (tramp_size);
framesize = 0;
/* Argument area */
framesize += sizeof (target_mgreg_t);
framesize = ALIGN_TO (framesize, 8);
ctx_offset = framesize;
framesize += sizeof (MonoContext);
framesize = ALIGN_TO (framesize, MONO_ARCH_FRAME_ALIGNMENT);
// CFA = sp + 4
cfa_offset = 4;
mono_add_unwind_op_def_cfa (unwind_ops, code, buf, X86_ESP, 4);
// IP saved at CFA - 4
mono_add_unwind_op_offset (unwind_ops, code, buf, X86_NREG, -cfa_offset);
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);
/* The + 8 makes the stack aligned */
x86_alu_reg_imm (code, X86_SUB, X86_ESP, framesize + 8);
/* Initialize a MonoContext structure on the stack */
x86_mov_membase_reg (code, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, eax), X86_EAX, sizeof (target_mgreg_t));
x86_mov_membase_reg (code, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, ebx), X86_EBX, sizeof (target_mgreg_t));
x86_mov_membase_reg (code, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, ecx), X86_ECX, sizeof (target_mgreg_t));
x86_mov_membase_reg (code, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, edx), X86_EDX, sizeof (target_mgreg_t));
x86_mov_reg_membase (code, X86_EAX, X86_EBP, 0, sizeof (target_mgreg_t));
x86_mov_membase_reg (code, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, ebp), X86_EAX, sizeof (target_mgreg_t));
x86_mov_reg_reg (code, X86_EAX, X86_EBP);
x86_alu_reg_imm (code, X86_ADD, X86_EAX, cfa_offset);
x86_mov_membase_reg (code, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, esp), X86_ESP, sizeof (target_mgreg_t));
x86_mov_membase_reg (code, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, esi), X86_ESI, sizeof (target_mgreg_t));
x86_mov_membase_reg (code, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, edi), X86_EDI, sizeof (target_mgreg_t));
x86_mov_reg_membase (code, X86_EAX, X86_EBP, 4, sizeof (target_mgreg_t));
x86_mov_membase_reg (code, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, eip), X86_EAX, sizeof (target_mgreg_t));
/* Call the single step/breakpoint function in sdb */
x86_lea_membase (code, X86_EAX, X86_ESP, ctx_offset);
x86_mov_membase_reg (code, X86_ESP, 0, X86_EAX, sizeof (target_mgreg_t));
if (aot) {
x86_breakpoint (code);
} else {
if (single_step)
x86_call_code (code, mini_get_dbg_callbacks ()->single_step_from_context);
else
x86_call_code (code, mini_get_dbg_callbacks ()->breakpoint_from_context);
}
/* Restore registers from ctx */
/* Overwrite the saved ebp */
x86_mov_reg_membase (code, X86_EAX, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, ebp), sizeof (target_mgreg_t));
x86_mov_membase_reg (code, X86_EBP, 0, X86_EAX, sizeof (target_mgreg_t));
/* Overwrite saved eip */
x86_mov_reg_membase (code, X86_EAX, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, eip), sizeof (target_mgreg_t));
x86_mov_membase_reg (code, X86_EBP, 4, X86_EAX, sizeof (target_mgreg_t));
x86_mov_reg_membase (code, X86_EAX, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, eax), sizeof (target_mgreg_t));
x86_mov_reg_membase (code, X86_EBX, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, ebx), sizeof (target_mgreg_t));
x86_mov_reg_membase (code, X86_ECX, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, ecx), sizeof (target_mgreg_t));
x86_mov_reg_membase (code, X86_EDX, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, edx), sizeof (target_mgreg_t));
x86_mov_reg_membase (code, X86_ESI, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, esi), sizeof (target_mgreg_t));
x86_mov_reg_membase (code, X86_EDI, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, edi), sizeof (target_mgreg_t));
x86_leave (code);
cfa_offset -= sizeof (target_mgreg_t);
mono_add_unwind_op_def_cfa (unwind_ops, code, buf, X86_ESP, cfa_offset);
x86_ret (code);
mono_arch_flush_icache (code, code - buf);
MONO_PROFILER_RAISE (jit_code_buffer, (buf, code - buf, MONO_PROFILER_CODE_BUFFER_HELPER, NULL));
g_assert (code - buf <= tramp_size);
const char *tramp_name = single_step ? "sdb_single_step_trampoline" : "sdb_breakpoint_trampoline";
*info = mono_tramp_info_create (tramp_name, buf, code - buf, ji, unwind_ops);
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;
}
/*
* get_throw_trampoline:
*
* Generate a call to mono_x86_throw_exception/
* mono_x86_throw_corlib_exception.
* If LLVM is true, generate code which assumes the caller is LLVM generated code,
* which doesn't push the arguments.
*/
static guint8*
get_throw_trampoline (const char *name, gboolean rethrow, gboolean llvm, gboolean corlib, gboolean llvm_abs, gboolean resume_unwind, MonoTrampInfo **info, gboolean aot)
{
guint8 *start, *code;
int i, stack_size, stack_offset, arg_offsets [5], regs_offset;
MonoJumpInfo *ji = NULL;
GSList *unwind_ops = NULL;
start = code = mono_global_codeman_reserve (128);
stack_size = 128;
/*
* On apple, the stack is misaligned by the pushing of the return address.
*/
if (!llvm && corlib)
/* On OSX, we don't generate alignment code to save space */
stack_size += 4;
else
stack_size += MONO_ARCH_FRAME_ALIGNMENT - 4;
/*
* The stack looks like this:
* <pc offset> (only if corlib is TRUE)
* <exception object>/<type token>
* <return addr> <- esp (unaligned on apple)
*/
mono_add_unwind_op_def_cfa (unwind_ops, (guint8*)NULL, (guint8*)NULL, X86_ESP, 4);
mono_add_unwind_op_offset (unwind_ops, (guint8*)NULL, (guint8*)NULL, X86_NREG, -4);
/* Alloc frame */
x86_alu_reg_imm (code, X86_SUB, X86_ESP, stack_size);
mono_add_unwind_op_def_cfa_offset (unwind_ops, code, start, stack_size + 4);
arg_offsets [0] = 0;
arg_offsets [1] = 4;
arg_offsets [2] = 8;
arg_offsets [3] = 12;
regs_offset = 16;
/* Save registers */
for (i = 0; i < X86_NREG; ++i)
if (i != X86_ESP)
x86_mov_membase_reg (code, X86_ESP, regs_offset + (i * 4), i, 4);
/* Calculate the offset between the current sp and the sp of the caller */
if (llvm) {
/* LLVM doesn't push the arguments */
stack_offset = stack_size + 4;
} else {
if (corlib) {
/* Two arguments */
stack_offset = stack_size + 4 + 8;
#ifdef __APPLE__
/* We don't generate stack alignment code on osx to save space */
#endif
} else {
/* One argument */
stack_offset = stack_size + 4 + 4;
#ifdef __APPLE__
/* Pop the alignment added by OP_THROW too */
stack_offset += MONO_ARCH_FRAME_ALIGNMENT - 4;
#endif
}
}
/* Save ESP */
x86_lea_membase (code, X86_EAX, X86_ESP, stack_offset);
x86_mov_membase_reg (code, X86_ESP, regs_offset + (X86_ESP * 4), X86_EAX, 4);
/* Set arg1 == regs */
x86_lea_membase (code, X86_EAX, X86_ESP, regs_offset);
x86_mov_membase_reg (code, X86_ESP, arg_offsets [0], X86_EAX, 4);
/* Set arg2 == exc/ex_token_index */
if (resume_unwind)
x86_mov_reg_imm (code, X86_EAX, 0);
else
x86_mov_reg_membase (code, X86_EAX, X86_ESP, stack_size + 4, 4);
x86_mov_membase_reg (code, X86_ESP, arg_offsets [1], X86_EAX, 4);
/* Set arg3 == eip */
if (llvm_abs)
x86_alu_reg_reg (code, X86_XOR, X86_EAX, X86_EAX);
else
x86_mov_reg_membase (code, X86_EAX, X86_ESP, stack_size, 4);
x86_mov_membase_reg (code, X86_ESP, arg_offsets [2], X86_EAX, 4);
/* Set arg4 == rethrow/pc_offset */
if (resume_unwind) {
x86_mov_membase_imm (code, X86_ESP, arg_offsets [3], 0, 4);
} else if (corlib) {
x86_mov_reg_membase (code, X86_EAX, X86_ESP, stack_size + 8, 4);
if (llvm_abs) {
/*
* The caller is LLVM code which passes the absolute address not a pc offset,
* so compensate by passing 0 as 'ip' and passing the negated abs address as
* the pc offset.
*/
x86_neg_reg (code, X86_EAX);
}
x86_mov_membase_reg (code, X86_ESP, arg_offsets [3], X86_EAX, 4);
} else {
x86_mov_membase_imm (code, X86_ESP, arg_offsets [3], rethrow, 4);
}
/* Make the call */
if (aot) {
// This can be called from runtime code, which can't guarantee that
// ebx contains the got address.
// So emit the got address loading code too
code = mono_arch_emit_load_got_addr (start, code, NULL, &ji);
code = mono_arch_emit_load_aotconst (start, code, &ji, MONO_PATCH_INFO_JIT_ICALL_ADDR, corlib ? "mono_x86_throw_corlib_exception" : "mono_x86_throw_exception");
x86_call_reg (code, X86_EAX);
} else {
x86_call_code (code, resume_unwind ? (mono_x86_resume_unwind) : (corlib ? (gpointer)mono_x86_throw_corlib_exception : (gpointer)mono_x86_throw_exception));
}
x86_breakpoint (code);
g_assert ((code - start) < 128);
if (info)
*info = mono_tramp_info_create (g_strdup (name), start, code - start, ji, unwind_ops);
return start;
}
/*
* mono_arch_get_restore_context:
*
* Returns a pointer to a method which restores a previously saved sigcontext.
*/
gpointer
mono_arch_get_restore_context (MonoTrampInfo **info, gboolean aot)
{
guint8 *start = NULL;
guint8 *code;
MonoJumpInfo *ji = NULL;
GSList *unwind_ops = NULL;
/* restore_contect (MonoContext *ctx) */
start = code = mono_global_codeman_reserve (128);
/* load ctx */
x86_mov_reg_membase (code, X86_EAX, X86_ESP, 4, 4);
/* restore EBX */
x86_mov_reg_membase (code, X86_EBX, X86_EAX, G_STRUCT_OFFSET (MonoContext, ebx), 4);
/* restore EDI */
x86_mov_reg_membase (code, X86_EDI, X86_EAX, G_STRUCT_OFFSET (MonoContext, edi), 4);
/* restore ESI */
x86_mov_reg_membase (code, X86_ESI, X86_EAX, G_STRUCT_OFFSET (MonoContext, esi), 4);
/* restore EDX */
x86_mov_reg_membase (code, X86_EDX, X86_EAX, G_STRUCT_OFFSET (MonoContext, edx), 4);
/*
* The context resides on the stack, in the stack frame of the
* caller of this function. The stack pointer that we need to
* restore is potentially many stack frames higher up, so the
* distance between them can easily be more than the red zone
* size. Hence the stack pointer can be restored only after
* we have finished loading everything from the context.
*/
/* load ESP into EBP */
x86_mov_reg_membase (code, X86_EBP, X86_EAX, G_STRUCT_OFFSET (MonoContext, esp), 4);
/* Align it, it can be unaligned if it was captured asynchronously */
x86_alu_reg_imm (code, X86_AND, X86_EBP, ~(MONO_ARCH_LOCALLOC_ALIGNMENT - 1));
/* load return address into ECX */
x86_mov_reg_membase (code, X86_ECX, X86_EAX, G_STRUCT_OFFSET (MonoContext, eip), 4);
/* save the return addr to the restored stack - 4 */
x86_mov_membase_reg (code, X86_EBP, -4, X86_ECX, 4);
/* load EBP into ECX */
x86_mov_reg_membase (code, X86_ECX, X86_EAX, G_STRUCT_OFFSET (MonoContext, ebp), 4);
/* save EBP to the restored stack - 8 */
x86_mov_membase_reg (code, X86_EBP, -8, X86_ECX, 4);
/* load EAX into ECX */
x86_mov_reg_membase (code, X86_ECX, X86_EAX, G_STRUCT_OFFSET (MonoContext, eax), 4);
/* save EAX to the restored stack - 12 */
x86_mov_membase_reg (code, X86_EBP, -12, X86_ECX, 4);
/* restore ECX */
x86_mov_reg_membase (code, X86_ECX, X86_EAX, G_STRUCT_OFFSET (MonoContext, ecx), 4);
/* restore ESP - 12 */
x86_lea_membase (code, X86_ESP, X86_EBP, -12);
/* restore EAX */
x86_pop_reg (code, X86_EAX);
/* restore EBP */
x86_pop_reg (code, X86_EBP);
/* jump to the saved IP */
x86_ret (code);
nacl_global_codeman_validate(&start, 128, &code);
if (info)
*info = mono_tramp_info_create ("restore_context", start, code - start, ji, unwind_ops);
else {
GSList *l;
for (l = unwind_ops; l; l = l->next)
g_free (l->data);
g_slist_free (unwind_ops);
}
return start;
}
/*
* get_throw_exception:
*
* Generate a call to mono_x86_throw_exception/
* mono_x86_throw_corlib_exception.
* If LLVM is true, generate code which assumes the caller is LLVM generated code,
* which doesn't push the arguments.
*/
static guint8*
get_throw_exception (const char *name, gboolean rethrow, gboolean llvm, gboolean corlib)
{
guint8 *start, *code;
GSList *unwind_ops = NULL;
int i, stack_size, stack_offset, arg_offsets [5], regs_offset;
start = code = mono_global_codeman_reserve (128);
stack_size = 128;
/*
* On apple, the stack is misaligned by the pushing of the return address.
*/
if (!llvm && corlib)
/* On OSX, we don't generate alignment code to save space */
stack_size += 4;
else
stack_size += MONO_ARCH_FRAME_ALIGNMENT - 4;
/*
* The stack looks like this:
* <pc offset> (only if corlib is TRUE)
* <exception object>/<type token>
* <return addr> <- esp (unaligned on apple)
*/
mono_add_unwind_op_def_cfa (unwind_ops, (guint8*)NULL, (guint8*)NULL, X86_ESP, 4);
mono_add_unwind_op_offset (unwind_ops, (guint8*)NULL, (guint8*)NULL, X86_NREG, -4);
/* Alloc frame */
x86_alu_reg_imm (code, X86_SUB, X86_ESP, stack_size);
mono_add_unwind_op_def_cfa_offset (unwind_ops, code, start, stack_size + 4);
arg_offsets [0] = 0;
arg_offsets [1] = 4;
arg_offsets [2] = 8;
arg_offsets [3] = 12;
regs_offset = 16;
/* Save registers */
for (i = 0; i < X86_NREG; ++i)
if (i != X86_ESP)
x86_mov_membase_reg (code, X86_ESP, regs_offset + (i * 4), i, 4);
/* Calculate the offset between the current sp and the sp of the caller */
if (llvm) {
/* LLVM doesn't push the arguments */
stack_offset = stack_size + 4;
} else {
if (corlib) {
/* Two arguments */
stack_offset = stack_size + 4 + 8;
#ifdef __APPLE__
/* We don't generate stack alignment code on osx to save space */
#endif
} else {
/* One argument */
stack_offset = stack_size + 4 + 4;
#ifdef __APPLE__
/* Pop the alignment added by OP_THROW too */
stack_offset += MONO_ARCH_FRAME_ALIGNMENT - 4;
#endif
}
}
/* Save ESP */
x86_lea_membase (code, X86_EAX, X86_ESP, stack_offset);
x86_mov_membase_reg (code, X86_ESP, regs_offset + (X86_ESP * 4), X86_EAX, 4);
/* Set arg1 == regs */
x86_lea_membase (code, X86_EAX, X86_ESP, regs_offset);
x86_mov_membase_reg (code, X86_ESP, arg_offsets [0], X86_EAX, 4);
/* Set arg2 == exc */
x86_mov_reg_membase (code, X86_EAX, X86_ESP, stack_size + 4, 4);
x86_mov_membase_reg (code, X86_ESP, arg_offsets [1], X86_EAX, 4);
/* Set arg3 == eip */
x86_mov_reg_membase (code, X86_EAX, X86_ESP, stack_size, 4);
x86_mov_membase_reg (code, X86_ESP, arg_offsets [2], X86_EAX, 4);
if (corlib) {
/* Set arg4 == offset */
x86_mov_reg_membase (code, X86_EAX, X86_ESP, stack_size + 8, 4);
x86_mov_membase_reg (code, X86_ESP, arg_offsets [3], X86_EAX, 4);
} else {
/* Set arg4 == rethrow */
x86_mov_membase_imm (code, X86_ESP, arg_offsets [3], rethrow, 4);
}
/* Make the call */
x86_call_code (code, corlib ? (gpointer)mono_x86_throw_corlib_exception : (gpointer)mono_x86_throw_exception);
x86_breakpoint (code);
g_assert ((code - start) < 128);
mono_save_trampoline_xdebug_info (corlib ? "llvm_throw_corlib_exception_trampoline" : "llvm_throw_exception_trampoline", start, code - start, unwind_ops);
return start;
}