2 * trampoline.c: JIT trampoline code
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 InterlockedExchange ((gint32*)(code + 2), (guint)addr - ((guint)code + 1) - 5);
128 #ifdef HAVE_VALGRIND_MEMCHECK_H
129 /* Tell valgrind to recompile the patched code */
130 VALGRIND_DISCARD_TRANSLATIONS (code + 2, code + 6);
134 } else if ((code [4] == 0xff) && (((code [5] >> 6) & 0x3) == 0) && (((code [5] >> 3) & 0x7) == 2)) {
136 * This is a interface call: should check the above code can't catch it earlier
137 * 8b 40 30 mov 0x30(%eax),%eax
141 reg = code [5] & 0x07;
143 printf ("Invalid trampoline sequence: %x %x %x %x %x %x %x\n", code [0], code [1], code [2], code [3],
144 code [4], code [5], code [6]);
145 g_assert_not_reached ();
169 g_assert_not_reached ();
174 if (m->klass->valuetype)
175 addr = get_unbox_trampoline (m, addr);
177 *((gpointer *)o) = addr;
183 * x86_class_init_trampoline:
184 * @eax: saved x86 register
185 * @ecx: saved x86 register
186 * @edx: saved x86 register
187 * @esi: saved x86 register
188 * @edi: saved x86 register
189 * @ebx: saved x86 register
190 * @code: pointer into caller code
191 * @vtable: the type to initialize
193 * This method calls mono_runtime_class_init () to run the static constructor
194 * for the type, then patches the caller code so it is not called again.
197 x86_class_init_trampoline (int eax, int ecx, int edx, int esi, int edi,
198 int ebx, guint8 *code, MonoVTable *vtable)
200 mono_runtime_class_init (vtable);
203 if (code [0] == 0xe8) {
206 * Thread safe code patching using the algorithm from the paper
207 * 'Practicing JUDO: Java Under Dynamic Optimizations'
210 * First atomically change the the first 2 bytes of the call to a
214 InterlockedExchange ((gint32*)code, ops);
216 /* Then change the other bytes to a nop */
221 /* Then atomically change the first 4 bytes to a nop as well */
223 InterlockedExchange ((guint32*)code, ops);
225 #ifdef HAVE_VALGRIND_MEMCHECK_H
226 /* FIXME: the calltree skin trips on the self modifying code above */
228 /* Tell valgrind to recompile the patched code */
229 VALGRIND_DISCARD_TRANSLATIONS (code, code + 8);
233 if (code [0] == 0x90 || code [0] == 0xeb)
234 /* Already changed by another thread */
237 printf ("Invalid trampoline sequence: %x %x %x %x %x %x %x\n", code [0], code [1], code [2], code [3],
238 code [4], code [5], code [6]);
239 g_assert_not_reached ();
244 create_trampoline_code (MonoTrampolineType tramp_type)
247 static guint8* generic_jump_trampoline = NULL;
248 static guint8 *generic_class_init_trampoline = NULL;
250 switch (tramp_type) {
251 case MONO_TRAMPOLINE_GENERIC:
252 if (mono_generic_trampoline_code)
253 return mono_generic_trampoline_code;
255 case MONO_TRAMPOLINE_JUMP:
256 if (generic_jump_trampoline)
257 return generic_jump_trampoline;
259 case MONO_TRAMPOLINE_CLASS_INIT:
260 if (generic_class_init_trampoline)
261 return generic_class_init_trampoline;
265 code = buf = g_malloc (256);
266 /* save caller save regs because we need to do a call */
267 x86_push_reg (buf, X86_EDX);
268 x86_push_reg (buf, X86_EAX);
269 x86_push_reg (buf, X86_ECX);
273 /* save the IP (caller ip) */
274 if (tramp_type == MONO_TRAMPOLINE_JUMP)
275 x86_push_imm (buf, 0);
277 x86_push_membase (buf, X86_ESP, 16);
279 x86_push_reg (buf, X86_EBX);
280 x86_push_reg (buf, X86_EDI);
281 x86_push_reg (buf, X86_ESI);
282 x86_push_reg (buf, X86_EBP);
284 /* save method info */
285 x86_push_membase (buf, X86_ESP, 32);
286 /* get the address of lmf for the current thread */
287 x86_call_code (buf, mono_get_lmf_addr);
289 x86_push_reg (buf, X86_EAX);
290 /* push *lfm (previous_lmf) */
291 x86_push_membase (buf, X86_EAX, 0);
293 x86_mov_membase_reg (buf, X86_EAX, 0, X86_ESP, 4);
296 /* push the method info */
297 x86_push_membase (buf, X86_ESP, 44);
298 /* push the return address onto the stack */
299 if (tramp_type == MONO_TRAMPOLINE_JUMP)
300 x86_push_imm (buf, 0);
302 x86_push_membase (buf, X86_ESP, 52);
304 /* save all register values */
305 x86_push_reg (buf, X86_EBX);
306 x86_push_reg (buf, X86_EDI);
307 x86_push_reg (buf, X86_ESI);
308 x86_push_membase (buf, X86_ESP, 64); /* EDX */
309 x86_push_membase (buf, X86_ESP, 64); /* ECX */
310 x86_push_membase (buf, X86_ESP, 64); /* EAX */
312 if (tramp_type == MONO_TRAMPOLINE_CLASS_INIT)
313 x86_call_code (buf, x86_class_init_trampoline);
315 x86_call_code (buf, x86_magic_trampoline);
316 x86_alu_reg_imm (buf, X86_ADD, X86_ESP, 8*4);
318 /* restore LMF start */
319 /* ebx = previous_lmf */
320 x86_pop_reg (buf, X86_EBX);
322 x86_pop_reg (buf, X86_EDI);
323 /* *(lmf) = previous_lmf */
324 x86_mov_membase_reg (buf, X86_EDI, 0, X86_EBX, 4);
325 /* discard method info */
326 x86_pop_reg (buf, X86_ESI);
327 /* restore caller saved regs */
328 x86_pop_reg (buf, X86_EBP);
329 x86_pop_reg (buf, X86_ESI);
330 x86_pop_reg (buf, X86_EDI);
331 x86_pop_reg (buf, X86_EBX);
332 /* discard save IP */
333 x86_alu_reg_imm (buf, X86_ADD, X86_ESP, 4);
334 /* restore LMF end */
336 x86_alu_reg_imm (buf, X86_ADD, X86_ESP, 16);
338 if (tramp_type == MONO_TRAMPOLINE_CLASS_INIT)
341 /* call the compiled method */
342 x86_jump_reg (buf, X86_EAX);
344 g_assert ((buf - code) <= 256);
346 switch (tramp_type) {
347 case MONO_TRAMPOLINE_GENERIC:
348 mono_generic_trampoline_code = code;
350 case MONO_TRAMPOLINE_JUMP:
351 generic_jump_trampoline = code;
353 case MONO_TRAMPOLINE_CLASS_INIT:
354 generic_class_init_trampoline = code;
361 #define TRAMPOLINE_SIZE 10
364 mono_arch_create_jump_trampoline (MonoMethod *method)
366 guint8 *code, *buf, *tramp;
368 if (method->iflags & METHOD_IMPL_ATTRIBUTE_SYNCHRONIZED)
369 return mono_arch_create_jump_trampoline (mono_marshal_get_synchronized_wrapper (method));
371 /* icalls use method->addr */
372 if ((method->iflags & METHOD_IMPL_ATTRIBUTE_INTERNAL_CALL) ||
373 (method->flags & METHOD_ATTRIBUTE_PINVOKE_IMPL)) {
377 if (method->iflags & METHOD_IMPL_ATTRIBUTE_INTERNAL_CALL)
378 method->addr = mono_lookup_internal_call (method);
379 if (method->flags & METHOD_ATTRIBUTE_PINVOKE_IMPL)
380 mono_lookup_pinvoke_call (method);
382 #ifdef MONO_USE_EXC_TABLES
383 if (mono_method_blittable (method)) {
387 nm = mono_marshal_get_native_wrapper (method);
388 return mono_compile_method (nm);
389 #ifdef MONO_USE_EXC_TABLES
394 tramp = create_trampoline_code (MONO_TRAMPOLINE_JUMP);
396 code = buf = g_malloc (TRAMPOLINE_SIZE);
397 x86_push_imm (buf, method);
398 x86_jump_code (buf, tramp);
399 g_assert ((buf - code) <= TRAMPOLINE_SIZE);
401 mono_jit_stats.method_trampolines++;
408 * mono_arch_create_jit_trampoline:
409 * @method: pointer to the method info
411 * Creates a trampoline function for virtual methods. If the created
412 * code is called it first starts JIT compilation of method,
413 * and then calls the newly created method. I also replaces the
414 * corresponding vtable entry (see x86_magic_trampoline).
416 * Returns: a pointer to the newly created code
419 mono_arch_create_jit_trampoline (MonoMethod *method)
421 guint8 *code, *buf, *tramp;
423 /* previously created trampoline code */
427 if (method->iflags & METHOD_IMPL_ATTRIBUTE_SYNCHRONIZED)
428 return mono_arch_create_jit_trampoline (mono_marshal_get_synchronized_wrapper (method));
430 tramp = create_trampoline_code (MONO_TRAMPOLINE_GENERIC);
432 code = buf = g_malloc (TRAMPOLINE_SIZE);
433 x86_push_imm (buf, method);
434 x86_jump_code (buf, tramp);
435 g_assert ((buf - code) <= TRAMPOLINE_SIZE);
437 /* store trampoline address */
440 mono_jit_stats.method_trampolines++;
446 * mono_arch_create_class_init_trampoline:
447 * @vtable: the type to initialize
449 * Creates a trampoline function to run a type initializer.
450 * If the trampoline is called, it calls mono_runtime_class_init with the
451 * given vtable, then patches the caller code so it does not get called any
454 * Returns: a pointer to the newly created code
457 mono_arch_create_class_init_trampoline (MonoVTable *vtable)
459 guint8 *code, *buf, *tramp;
461 tramp = create_trampoline_code (MONO_TRAMPOLINE_CLASS_INIT);
463 code = buf = g_malloc (TRAMPOLINE_SIZE);
464 x86_push_imm (buf, vtable);
465 x86_jump_code (buf, tramp);
466 g_assert ((buf - code) <= TRAMPOLINE_SIZE);
468 mono_jit_stats.method_trampolines++;
474 * This method is only called when running in the Mono Debugger.
477 mono_debugger_create_notification_function (gpointer *notification_address)
481 ptr = buf = g_malloc0 (16);
482 x86_breakpoint (buf);
483 if (notification_address)
484 *notification_address = buf;