2 * tramp-x86.c: JIT trampoline code for x86
5 * Dietmar Maurer (dietmar@ximian.com)
7 * (C) 2001 Ximian, Inc.
13 #include <mono/metadata/appdomain.h>
14 #include <mono/metadata/marshal.h>
15 #include <mono/metadata/tabledefs.h>
16 #include <mono/arch/x86/x86-codegen.h>
17 #include <mono/metadata/mono-debug-debugger.h>
19 #ifdef HAVE_VALGRIND_MEMCHECK_H
20 #include <valgrind/memcheck.h>
27 MONO_TRAMPOLINE_GENERIC,
29 MONO_TRAMPOLINE_CLASS_INIT
32 /* adapt to mini later... */
33 #define mono_jit_share_code (1)
36 * Address of the x86 trampoline code. This is used by the debugger to check
37 * whether a method is a trampoline.
39 guint8 *mono_generic_trampoline_code = NULL;
42 * get_unbox_trampoline:
44 * @addr: pointer to native code for @m
46 * when value type methods are called through the vtable we need to unbox the
47 * this argument. This method returns a pointer to a trampoline which does
48 * unboxing before calling the method
51 get_unbox_trampoline (MonoMethod *m, gpointer addr)
56 if (!m->signature->ret->byref && MONO_TYPE_ISSTRUCT (m->signature->ret))
59 start = code = g_malloc (16);
61 x86_alu_membase_imm (code, X86_ADD, X86_ESP, this_pos, sizeof (MonoObject));
62 x86_jump_code (code, addr);
63 g_assert ((code - start) < 16);
69 * x86_magic_trampoline:
70 * @eax: saved x86 register
71 * @ecx: saved x86 register
72 * @edx: saved x86 register
73 * @esi: saved x86 register
74 * @edi: saved x86 register
75 * @ebx: saved x86 register
76 * @code: pointer into caller code
77 * @method: the method to translate
79 * This method is called by the trampoline functions for virtual
80 * methods. It inspects the caller code to find the address of the
81 * vtable slot, then calls the JIT compiler and writes the address
82 * of the compiled method back to the vtable. All virtual methods
83 * are called with: x86_call_membase (inst, basereg, disp). We always
84 * use 32 bit displacement to ensure that the length of the call
85 * instruction is 6 bytes. We need to get the value of the basereg
86 * and the constant displacement.
89 x86_magic_trampoline (int eax, int ecx, int edx, int esi, int edi,
90 int ebx, guint8 *code, MonoMethod *m)
97 addr = mono_compile_method (m);
100 /* the method was jumped to */
104 /* go to the start of the call instruction
106 * address_byte = (m << 6) | (o << 3) | reg
107 * call opcode: 0xff address_byte displacement
112 if ((code [1] != 0xe8) && (code [3] == 0xff) && ((code [4] & 0x18) == 0x10) && ((code [4] >> 6) == 1)) {
113 reg = code [4] & 0x07;
114 disp = (signed char)code [5];
116 if ((code [0] == 0xff) && ((code [1] & 0x18) == 0x10) && ((code [1] >> 6) == 2)) {
117 reg = code [1] & 0x07;
118 disp = *((gint32*)(code + 2));
119 } else if ((code [1] == 0xe8)) {
121 mono_jit_info_table_find (mono_domain_get (), code);
122 MonoJitInfo *target_ji =
123 mono_jit_info_table_find (mono_domain_get (), addr);
125 /* The first part of the condition means an icall without a wrapper */
126 if ((!target_ji && m->addr) || mono_method_same_domain (ji, target_ji)) {
127 gboolean do_patch = TRUE;
129 #ifdef HAVE_VALGRIND_MEMCHECK_H
130 if (RUNNING_ON_VALGRIND)
135 InterlockedExchange ((gint32*)(code + 2), (guint)addr - ((guint)code + 1) - 5);
137 #ifdef HAVE_VALGRIND_MEMCHECK_H
138 /* Tell valgrind to recompile the patched code */
139 VALGRIND_DISCARD_TRANSLATIONS (code + 2, code + 6);
144 } else if ((code [4] == 0xff) && (((code [5] >> 6) & 0x3) == 0) && (((code [5] >> 3) & 0x7) == 2)) {
146 * This is a interface call: should check the above code can't catch it earlier
147 * 8b 40 30 mov 0x30(%eax),%eax
151 reg = code [5] & 0x07;
153 printf ("Invalid trampoline sequence: %x %x %x %x %x %x %x\n", code [0], code [1], code [2], code [3],
154 code [4], code [5], code [6]);
155 g_assert_not_reached ();
179 g_assert_not_reached ();
184 if (m->klass->valuetype)
185 addr = get_unbox_trampoline (m, addr);
187 *((gpointer *)o) = addr;
193 * x86_class_init_trampoline:
194 * @eax: saved x86 register
195 * @ecx: saved x86 register
196 * @edx: saved x86 register
197 * @esi: saved x86 register
198 * @edi: saved x86 register
199 * @ebx: saved x86 register
200 * @code: pointer into caller code
201 * @vtable: the type to initialize
203 * This method calls mono_runtime_class_init () to run the static constructor
204 * for the type, then patches the caller code so it is not called again.
207 x86_class_init_trampoline (int eax, int ecx, int edx, int esi, int edi,
208 int ebx, guint8 *code, MonoVTable *vtable)
210 mono_runtime_class_init (vtable);
213 if (code [0] == 0xe8) {
214 gboolean do_patch = TRUE;
216 #ifdef HAVE_VALGRIND_MEMCHECK_H
217 if (RUNNING_ON_VALGRIND)
224 * Thread safe code patching using the algorithm from the paper
225 * 'Practicing JUDO: Java Under Dynamic Optimizations'
228 * First atomically change the the first 2 bytes of the call to a
232 InterlockedExchange ((gint32*)code, ops);
234 /* Then change the other bytes to a nop */
239 /* Then atomically change the first 4 bytes to a nop as well */
241 InterlockedExchange ((guint32*)code, ops);
243 #ifdef HAVE_VALGRIND_MEMCHECK_H
244 /* FIXME: the calltree skin trips on the self modifying code above */
246 /* Tell valgrind to recompile the patched code */
247 //VALGRIND_DISCARD_TRANSLATIONS (code, code + 8);
252 if (code [0] == 0x90 || code [0] == 0xeb)
253 /* Already changed by another thread */
256 printf ("Invalid trampoline sequence: %x %x %x %x %x %x %x\n", code [0], code [1], code [2], code [3],
257 code [4], code [5], code [6]);
258 g_assert_not_reached ();
263 create_trampoline_code (MonoTrampolineType tramp_type)
266 static guint8* generic_jump_trampoline = NULL;
267 static guint8 *generic_class_init_trampoline = NULL;
269 switch (tramp_type) {
270 case MONO_TRAMPOLINE_GENERIC:
271 if (mono_generic_trampoline_code)
272 return mono_generic_trampoline_code;
274 case MONO_TRAMPOLINE_JUMP:
275 if (generic_jump_trampoline)
276 return generic_jump_trampoline;
278 case MONO_TRAMPOLINE_CLASS_INIT:
279 if (generic_class_init_trampoline)
280 return generic_class_init_trampoline;
284 code = buf = g_malloc (256);
285 /* save caller save regs because we need to do a call */
286 x86_push_reg (buf, X86_EDX);
287 x86_push_reg (buf, X86_EAX);
288 x86_push_reg (buf, X86_ECX);
292 /* save the IP (caller ip) */
293 if (tramp_type == MONO_TRAMPOLINE_JUMP)
294 x86_push_imm (buf, 0);
296 x86_push_membase (buf, X86_ESP, 16);
298 x86_push_reg (buf, X86_EBX);
299 x86_push_reg (buf, X86_EDI);
300 x86_push_reg (buf, X86_ESI);
301 x86_push_reg (buf, X86_EBP);
303 /* save method info */
304 x86_push_membase (buf, X86_ESP, 32);
305 /* get the address of lmf for the current thread */
306 x86_call_code (buf, mono_get_lmf_addr);
308 x86_push_reg (buf, X86_EAX);
309 /* push *lfm (previous_lmf) */
310 x86_push_membase (buf, X86_EAX, 0);
312 x86_mov_membase_reg (buf, X86_EAX, 0, X86_ESP, 4);
315 /* push the method info */
316 x86_push_membase (buf, X86_ESP, 44);
317 /* push the return address onto the stack */
318 if (tramp_type == MONO_TRAMPOLINE_JUMP)
319 x86_push_imm (buf, 0);
321 x86_push_membase (buf, X86_ESP, 52);
323 /* save all register values */
324 x86_push_reg (buf, X86_EBX);
325 x86_push_reg (buf, X86_EDI);
326 x86_push_reg (buf, X86_ESI);
327 x86_push_membase (buf, X86_ESP, 64); /* EDX */
328 x86_push_membase (buf, X86_ESP, 64); /* ECX */
329 x86_push_membase (buf, X86_ESP, 64); /* EAX */
331 if (tramp_type == MONO_TRAMPOLINE_CLASS_INIT)
332 x86_call_code (buf, x86_class_init_trampoline);
334 x86_call_code (buf, x86_magic_trampoline);
335 x86_alu_reg_imm (buf, X86_ADD, X86_ESP, 8*4);
337 /* restore LMF start */
338 /* ebx = previous_lmf */
339 x86_pop_reg (buf, X86_EBX);
341 x86_pop_reg (buf, X86_EDI);
342 /* *(lmf) = previous_lmf */
343 x86_mov_membase_reg (buf, X86_EDI, 0, X86_EBX, 4);
344 /* discard method info */
345 x86_pop_reg (buf, X86_ESI);
346 /* restore caller saved regs */
347 x86_pop_reg (buf, X86_EBP);
348 x86_pop_reg (buf, X86_ESI);
349 x86_pop_reg (buf, X86_EDI);
350 x86_pop_reg (buf, X86_EBX);
351 /* discard save IP */
352 x86_alu_reg_imm (buf, X86_ADD, X86_ESP, 4);
353 /* restore LMF end */
355 x86_alu_reg_imm (buf, X86_ADD, X86_ESP, 16);
357 if (tramp_type == MONO_TRAMPOLINE_CLASS_INIT)
360 /* call the compiled method */
361 x86_jump_reg (buf, X86_EAX);
363 g_assert ((buf - code) <= 256);
365 switch (tramp_type) {
366 case MONO_TRAMPOLINE_GENERIC:
367 mono_generic_trampoline_code = code;
369 case MONO_TRAMPOLINE_JUMP:
370 generic_jump_trampoline = code;
372 case MONO_TRAMPOLINE_CLASS_INIT:
373 generic_class_init_trampoline = code;
380 #define TRAMPOLINE_SIZE 10
383 mono_arch_create_jump_trampoline (MonoMethod *method)
385 guint8 *code, *buf, *tramp;
387 if (method->iflags & METHOD_IMPL_ATTRIBUTE_SYNCHRONIZED)
388 return mono_arch_create_jump_trampoline (mono_marshal_get_synchronized_wrapper (method));
390 /* icalls use method->addr */
391 if ((method->iflags & METHOD_IMPL_ATTRIBUTE_INTERNAL_CALL) ||
392 (method->flags & METHOD_ATTRIBUTE_PINVOKE_IMPL)) {
396 if (method->iflags & METHOD_IMPL_ATTRIBUTE_INTERNAL_CALL)
397 method->addr = mono_lookup_internal_call (method);
398 if (method->flags & METHOD_ATTRIBUTE_PINVOKE_IMPL)
399 mono_lookup_pinvoke_call (method);
401 #ifdef MONO_USE_EXC_TABLES
402 if (mono_method_blittable (method)) {
406 nm = mono_marshal_get_native_wrapper (method);
407 return mono_compile_method (nm);
408 #ifdef MONO_USE_EXC_TABLES
413 tramp = create_trampoline_code (MONO_TRAMPOLINE_JUMP);
415 code = buf = g_malloc (TRAMPOLINE_SIZE);
416 x86_push_imm (buf, method);
417 x86_jump_code (buf, tramp);
418 g_assert ((buf - code) <= TRAMPOLINE_SIZE);
420 mono_jit_stats.method_trampolines++;
427 * mono_arch_create_jit_trampoline:
428 * @method: pointer to the method info
430 * Creates a trampoline function for virtual methods. If the created
431 * code is called it first starts JIT compilation of method,
432 * and then calls the newly created method. I also replaces the
433 * corresponding vtable entry (see x86_magic_trampoline).
435 * Returns: a pointer to the newly created code
438 mono_arch_create_jit_trampoline (MonoMethod *method)
440 guint8 *code, *buf, *tramp;
442 /* previously created trampoline code */
446 if (method->iflags & METHOD_IMPL_ATTRIBUTE_SYNCHRONIZED)
447 return mono_arch_create_jit_trampoline (mono_marshal_get_synchronized_wrapper (method));
449 tramp = create_trampoline_code (MONO_TRAMPOLINE_GENERIC);
451 code = buf = g_malloc (TRAMPOLINE_SIZE);
452 x86_push_imm (buf, method);
453 x86_jump_code (buf, tramp);
454 g_assert ((buf - code) <= TRAMPOLINE_SIZE);
456 /* store trampoline address */
459 mono_jit_stats.method_trampolines++;
465 * mono_arch_create_class_init_trampoline:
466 * @vtable: the type to initialize
468 * Creates a trampoline function to run a type initializer.
469 * If the trampoline is called, it calls mono_runtime_class_init with the
470 * given vtable, then patches the caller code so it does not get called any
473 * Returns: a pointer to the newly created code
476 mono_arch_create_class_init_trampoline (MonoVTable *vtable)
478 guint8 *code, *buf, *tramp;
480 tramp = create_trampoline_code (MONO_TRAMPOLINE_CLASS_INIT);
482 code = buf = g_malloc (TRAMPOLINE_SIZE);
483 x86_push_imm (buf, vtable);
484 x86_jump_code (buf, tramp);
485 g_assert ((buf - code) <= TRAMPOLINE_SIZE);
487 mono_jit_stats.method_trampolines++;
493 * This method is only called when running in the Mono Debugger.
496 mono_debugger_create_notification_function (gpointer *notification_address)
500 ptr = buf = g_malloc0 (16);
501 x86_breakpoint (buf);
502 if (notification_address)
503 *notification_address = buf;