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 if (!mono_running_on_valgrind ()) {
128 InterlockedExchange ((gint32*)(code + 2), (guint)addr - ((guint)code + 1) - 5);
130 #ifdef HAVE_VALGRIND_MEMCHECK_H
131 /* Tell valgrind to recompile the patched code */
132 //VALGRIND_DISCARD_TRANSLATIONS (code + 2, code + 6);
137 } else if ((code [4] == 0xff) && (((code [5] >> 6) & 0x3) == 0) && (((code [5] >> 3) & 0x7) == 2)) {
139 * This is a interface call: should check the above code can't catch it earlier
140 * 8b 40 30 mov 0x30(%eax),%eax
144 reg = code [5] & 0x07;
146 printf ("Invalid trampoline sequence: %x %x %x %x %x %x %x\n", code [0], code [1], code [2], code [3],
147 code [4], code [5], code [6]);
148 g_assert_not_reached ();
172 g_assert_not_reached ();
177 if (m->klass->valuetype)
178 addr = get_unbox_trampoline (m, addr);
180 *((gpointer *)o) = addr;
186 * x86_class_init_trampoline:
187 * @eax: saved x86 register
188 * @ecx: saved x86 register
189 * @edx: saved x86 register
190 * @esi: saved x86 register
191 * @edi: saved x86 register
192 * @ebx: saved x86 register
193 * @code: pointer into caller code
194 * @vtable: the type to initialize
196 * This method calls mono_runtime_class_init () to run the static constructor
197 * for the type, then patches the caller code so it is not called again.
200 x86_class_init_trampoline (int eax, int ecx, int edx, int esi, int edi,
201 int ebx, guint8 *code, MonoVTable *vtable)
203 mono_runtime_class_init (vtable);
206 if (code [0] == 0xe8) {
207 if (!mono_running_on_valgrind ()) {
210 * Thread safe code patching using the algorithm from the paper
211 * 'Practicing JUDO: Java Under Dynamic Optimizations'
214 * First atomically change the the first 2 bytes of the call to a
218 InterlockedExchange ((gint32*)code, ops);
220 /* Then change the other bytes to a nop */
225 /* Then atomically change the first 4 bytes to a nop as well */
227 InterlockedExchange ((guint32*)code, ops);
229 #ifdef HAVE_VALGRIND_MEMCHECK_H
230 /* FIXME: the calltree skin trips on the self modifying code above */
232 /* Tell valgrind to recompile the patched code */
233 //VALGRIND_DISCARD_TRANSLATIONS (code, code + 8);
238 if (code [0] == 0x90 || code [0] == 0xeb)
239 /* Already changed by another thread */
242 printf ("Invalid trampoline sequence: %x %x %x %x %x %x %x\n", code [0], code [1], code [2], code [3],
243 code [4], code [5], code [6]);
244 g_assert_not_reached ();
249 create_trampoline_code (MonoTrampolineType tramp_type)
252 static guint8* generic_jump_trampoline = NULL;
253 static guint8 *generic_class_init_trampoline = NULL;
255 switch (tramp_type) {
256 case MONO_TRAMPOLINE_GENERIC:
257 if (mono_generic_trampoline_code)
258 return mono_generic_trampoline_code;
260 case MONO_TRAMPOLINE_JUMP:
261 if (generic_jump_trampoline)
262 return generic_jump_trampoline;
264 case MONO_TRAMPOLINE_CLASS_INIT:
265 if (generic_class_init_trampoline)
266 return generic_class_init_trampoline;
270 code = buf = g_malloc (256);
271 /* save caller save regs because we need to do a call */
272 x86_push_reg (buf, X86_EDX);
273 x86_push_reg (buf, X86_EAX);
274 x86_push_reg (buf, X86_ECX);
278 /* save the IP (caller ip) */
279 if (tramp_type == MONO_TRAMPOLINE_JUMP)
280 x86_push_imm (buf, 0);
282 x86_push_membase (buf, X86_ESP, 16);
284 x86_push_reg (buf, X86_EBP);
285 x86_push_reg (buf, X86_ESI);
286 x86_push_reg (buf, X86_EDI);
287 x86_push_reg (buf, X86_EBX);
289 /* save method info */
290 x86_push_membase (buf, X86_ESP, 32);
291 /* get the address of lmf for the current thread */
292 x86_call_code (buf, mono_get_lmf_addr);
294 x86_push_reg (buf, X86_EAX);
295 /* push *lfm (previous_lmf) */
296 x86_push_membase (buf, X86_EAX, 0);
298 x86_mov_membase_reg (buf, X86_EAX, 0, X86_ESP, 4);
301 /* push the method info */
302 x86_push_membase (buf, X86_ESP, 44);
303 /* push the return address onto the stack */
304 if (tramp_type == MONO_TRAMPOLINE_JUMP)
305 x86_push_imm (buf, 0);
307 x86_push_membase (buf, X86_ESP, 52);
309 /* save all register values */
310 x86_push_reg (buf, X86_EBX);
311 x86_push_reg (buf, X86_EDI);
312 x86_push_reg (buf, X86_ESI);
313 x86_push_membase (buf, X86_ESP, 64); /* EDX */
314 x86_push_membase (buf, X86_ESP, 64); /* ECX */
315 x86_push_membase (buf, X86_ESP, 64); /* EAX */
317 if (tramp_type == MONO_TRAMPOLINE_CLASS_INIT)
318 x86_call_code (buf, x86_class_init_trampoline);
320 x86_call_code (buf, x86_magic_trampoline);
321 x86_alu_reg_imm (buf, X86_ADD, X86_ESP, 8*4);
323 /* restore LMF start */
324 /* ebx = previous_lmf */
325 x86_pop_reg (buf, X86_EBX);
327 x86_pop_reg (buf, X86_EDI);
328 /* *(lmf) = previous_lmf */
329 x86_mov_membase_reg (buf, X86_EDI, 0, X86_EBX, 4);
330 /* discard method info */
331 x86_pop_reg (buf, X86_ESI);
332 /* restore caller saved regs */
333 x86_pop_reg (buf, X86_EBX);
334 x86_pop_reg (buf, X86_EDI);
335 x86_pop_reg (buf, X86_ESI);
336 x86_pop_reg (buf, X86_EBP);
338 /* discard save IP */
339 x86_alu_reg_imm (buf, X86_ADD, X86_ESP, 4);
340 /* restore LMF end */
342 x86_alu_reg_imm (buf, X86_ADD, X86_ESP, 16);
344 if (tramp_type == MONO_TRAMPOLINE_CLASS_INIT)
347 /* call the compiled method */
348 x86_jump_reg (buf, X86_EAX);
350 g_assert ((buf - code) <= 256);
352 switch (tramp_type) {
353 case MONO_TRAMPOLINE_GENERIC:
354 mono_generic_trampoline_code = code;
356 case MONO_TRAMPOLINE_JUMP:
357 generic_jump_trampoline = code;
359 case MONO_TRAMPOLINE_CLASS_INIT:
360 generic_class_init_trampoline = code;
367 #define TRAMPOLINE_SIZE 10
370 mono_arch_create_jump_trampoline (MonoMethod *method)
372 guint8 *code, *buf, *tramp;
375 tramp = create_trampoline_code (MONO_TRAMPOLINE_JUMP);
377 code = buf = g_malloc (TRAMPOLINE_SIZE);
378 x86_push_imm (buf, method);
379 x86_jump_code (buf, tramp);
380 g_assert ((buf - code) <= TRAMPOLINE_SIZE);
382 ji = g_new0 (MonoJitInfo, 1);
384 ji->code_start = code;
385 ji->code_size = buf - code;
387 mono_arch_flush_icache (ji->code_start, ji->code_size);
389 mono_jit_stats.method_trampolines++;
396 * mono_arch_create_jit_trampoline:
397 * @method: pointer to the method info
399 * Creates a trampoline function for virtual methods. If the created
400 * code is called it first starts JIT compilation of method,
401 * and then calls the newly created method. I also replaces the
402 * corresponding vtable entry (see x86_magic_trampoline).
404 * Returns: a pointer to the newly created code
407 mono_arch_create_jit_trampoline (MonoMethod *method)
409 guint8 *code, *buf, *tramp;
411 /* previously created trampoline code */
415 if (method->iflags & METHOD_IMPL_ATTRIBUTE_SYNCHRONIZED)
416 return mono_arch_create_jit_trampoline (mono_marshal_get_synchronized_wrapper (method));
418 tramp = create_trampoline_code (MONO_TRAMPOLINE_GENERIC);
420 code = buf = g_malloc (TRAMPOLINE_SIZE);
421 x86_push_imm (buf, method);
422 x86_jump_code (buf, tramp);
423 g_assert ((buf - code) <= TRAMPOLINE_SIZE);
425 /* store trampoline address */
428 mono_jit_stats.method_trampolines++;
434 * mono_arch_create_class_init_trampoline:
435 * @vtable: the type to initialize
437 * Creates a trampoline function to run a type initializer.
438 * If the trampoline is called, it calls mono_runtime_class_init with the
439 * given vtable, then patches the caller code so it does not get called any
442 * Returns: a pointer to the newly created code
445 mono_arch_create_class_init_trampoline (MonoVTable *vtable)
447 guint8 *code, *buf, *tramp;
449 tramp = create_trampoline_code (MONO_TRAMPOLINE_CLASS_INIT);
451 code = buf = g_malloc (TRAMPOLINE_SIZE);
452 x86_push_imm (buf, vtable);
453 x86_jump_code (buf, tramp);
454 g_assert ((buf - code) <= TRAMPOLINE_SIZE);
456 mono_jit_stats.method_trampolines++;
462 * This method is only called when running in the Mono Debugger.
465 mono_debugger_create_notification_function (gpointer *notification_address)
469 ptr = buf = g_malloc0 (16);
470 x86_breakpoint (buf);
471 if (notification_address)
472 *notification_address = buf;