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/metadata-internals.h>
15 #include <mono/metadata/marshal.h>
16 #include <mono/metadata/tabledefs.h>
17 #include <mono/metadata/mono-debug.h>
18 #include <mono/metadata/mono-debug-debugger.h>
19 #include <mono/arch/x86/x86-codegen.h>
21 #ifdef HAVE_VALGRIND_MEMCHECK_H
22 #include <valgrind/memcheck.h>
28 static guint8* nullified_class_init_trampoline;
31 * mono_arch_get_unbox_trampoline:
33 * @addr: pointer to native code for @m
35 * when value type methods are called through the vtable we need to unbox the
36 * this argument. This method returns a pointer to a trampoline which does
37 * unboxing before calling the method
40 mono_arch_get_unbox_trampoline (MonoMethod *m, gpointer addr)
44 MonoDomain *domain = mono_domain_get ();
46 if (!mono_method_signature (m)->ret->byref && MONO_TYPE_ISSTRUCT (mono_method_signature (m)->ret))
49 mono_domain_lock (domain);
50 start = code = mono_code_manager_reserve (domain->code_mp, 16);
51 mono_domain_unlock (domain);
53 x86_alu_membase_imm (code, X86_ADD, X86_ESP, this_pos, sizeof (MonoObject));
54 x86_jump_code (code, addr);
55 g_assert ((code - start) < 16);
61 mono_arch_patch_callsite (guint8 *code, guint8 *addr)
63 /* go to the start of the call instruction
65 * address_byte = (m << 6) | (o << 3) | reg
66 * call opcode: 0xff address_byte displacement
71 if ((code [1] == 0xe8)) {
72 if (!mono_running_on_valgrind ()) {
73 InterlockedExchange ((gint32*)(code + 2), (guint)addr - ((guint)code + 1) - 5);
75 #ifdef HAVE_VALGRIND_MEMCHECK_H
76 /* Tell valgrind to recompile the patched code */
77 //VALGRIND_DISCARD_TRANSLATIONS (code + 2, code + 6);
81 printf ("Invalid trampoline sequence: %x %x %x %x %x %x %x\n", code [0], code [1], code [2], code [3],
82 code [4], code [5], code [6]);
83 g_assert_not_reached ();
88 mono_arch_nullify_class_init_trampoline (guint8 *code, gssize *regs)
91 if (code [0] == 0xe8) {
92 if (!mono_running_on_valgrind ()) {
95 * Thread safe code patching using the algorithm from the paper
96 * 'Practicing JUDO: Java Under Dynamic Optimizations'
99 * First atomically change the the first 2 bytes of the call to a
103 InterlockedExchange ((gint32*)code, ops);
105 /* Then change the other bytes to a nop */
110 /* Then atomically change the first 4 bytes to a nop as well */
112 InterlockedExchange ((gint32*)code, ops);
113 #ifdef HAVE_VALGRIND_MEMCHECK_H
114 /* FIXME: the calltree skin trips on the self modifying code above */
116 /* Tell valgrind to recompile the patched code */
117 //VALGRIND_DISCARD_TRANSLATIONS (code, code + 8);
120 } else if (code [0] == 0x90 || code [0] == 0xeb) {
121 /* Already changed by another thread */
123 } else if ((code [-1] == 0xff) && (x86_modrm_reg (code [0]) == 0x2)) {
124 /* call *<OFFSET>(<REG>) -> Call made from AOT code */
125 gpointer *vtable_slot;
127 vtable_slot = mono_arch_get_vcall_slot_addr (code + 5, (gpointer*)regs);
128 g_assert (vtable_slot);
130 *vtable_slot = nullified_class_init_trampoline;
132 printf ("Invalid trampoline sequence: %x %x %x %x %x %x %x\n", code [0], code [1], code [2], code [3],
133 code [4], code [5], code [6]);
134 g_assert_not_reached ();
139 mono_arch_patch_delegate_trampoline (guint8 *code, guint8 *tramp, gssize *regs, guint8 *addr)
144 if ((code [-3] == 0xff) && (x86_modrm_reg (code [-2]) == 0x2) && (x86_modrm_mod (code [-2]) == 0x1)) {
145 /* call *[reg+disp8] */
146 reg = x86_modrm_rm (code [-2]);
147 disp = *(guint8*)(code - 1);
148 //printf ("B: [%%r%d+0x%x]\n", reg, disp);
153 for (i = -16; i < 0; ++i)
154 printf ("%d ", code [i]);
156 g_assert_not_reached ();
159 *(gpointer*)(((guint32)(regs [reg])) + disp) = addr;
163 mono_arch_create_trampoline_code (MonoTrampolineType tramp_type)
168 code = buf = mono_global_codeman_reserve (256);
170 /* Note that there is a single argument to the trampoline
171 * and it is stored at: esp + pushed_args * sizeof (gpointer)
172 * the ret address is at: esp + (pushed_args + 1) * sizeof (gpointer)
174 /* Put all registers into an array on the stack */
175 x86_push_reg (buf, X86_EDI);
176 x86_push_reg (buf, X86_ESI);
177 x86_push_reg (buf, X86_EBP);
178 x86_push_reg (buf, X86_ESP);
179 x86_push_reg (buf, X86_EBX);
180 x86_push_reg (buf, X86_EDX);
181 x86_push_reg (buf, X86_ECX);
182 x86_push_reg (buf, X86_EAX);
188 /* save the IP (caller ip) */
189 if (tramp_type == MONO_TRAMPOLINE_JUMP)
190 x86_push_imm (buf, 0);
192 x86_push_membase (buf, X86_ESP, (pushed_args + 1) * sizeof (gpointer));
196 x86_push_reg (buf, X86_EBP);
197 x86_push_reg (buf, X86_ESI);
198 x86_push_reg (buf, X86_EDI);
199 x86_push_reg (buf, X86_EBX);
203 /* save method info */
204 x86_push_membase (buf, X86_ESP, pushed_args * sizeof (gpointer));
208 /* the stack is correctly aligned to 16 bytes because pushed_args is 14
209 * and there is the extra trampoline arg + the return ip pushed by call
210 * FIXME: Note that if an exception happens while some args are pushed
211 * on the stack, the stack will be misaligned.
214 g_assert (pushed_args == 14);
216 /* get the address of lmf for the current thread */
217 x86_call_code (buf, mono_get_lmf_addr);
219 x86_push_reg (buf, X86_EAX);
220 /* push *lfm (previous_lmf) */
221 x86_push_membase (buf, X86_EAX, 0);
223 x86_mov_membase_reg (buf, X86_EAX, 0, X86_ESP, 4);
228 /* starting the call sequence */
230 /* changing esp to keep the stack aligned */
231 x86_alu_reg_imm (buf, X86_SUB, X86_ESP, 8);
235 /* FIXME: Push the trampoline address */
236 x86_push_imm (buf, 0);
240 /* push the method info */
241 x86_push_membase (buf, X86_ESP, pushed_args * sizeof (gpointer));
245 /* push the return address onto the stack */
246 if (tramp_type == MONO_TRAMPOLINE_JUMP)
247 x86_push_imm (buf, 0);
249 x86_push_membase (buf, X86_ESP, (pushed_args + 1) * sizeof (gpointer));
251 /* push the address of the register array */
252 x86_lea_membase (buf, X86_EAX, X86_ESP, (pushed_args - 8) * sizeof (gpointer));
253 x86_push_reg (buf, X86_EAX);
258 /* check the stack is aligned after the ret ip is pushed */
259 /*x86_mov_reg_reg (buf, X86_EDX, X86_ESP, 4);
260 x86_alu_reg_imm (buf, X86_AND, X86_EDX, 15);
261 x86_alu_reg_imm (buf, X86_CMP, X86_EDX, 0);
262 x86_branch_disp (buf, X86_CC_Z, 3, FALSE);
263 x86_breakpoint (buf);*/
266 if (tramp_type == MONO_TRAMPOLINE_CLASS_INIT)
267 x86_call_code (buf, mono_class_init_trampoline);
268 else if (tramp_type == MONO_TRAMPOLINE_AOT)
269 x86_call_code (buf, mono_aot_trampoline);
270 else if (tramp_type == MONO_TRAMPOLINE_DELEGATE)
271 x86_call_code (buf, mono_delegate_trampoline);
273 x86_call_code (buf, mono_magic_trampoline);
276 /* account for the alignment above */
277 x86_alu_reg_imm (buf, X86_ADD, X86_ESP, 6*4);
279 x86_alu_reg_imm (buf, X86_ADD, X86_ESP, 4*4);
282 /* restore LMF start */
283 /* ebx = previous_lmf */
284 x86_pop_reg (buf, X86_EBX);
286 x86_pop_reg (buf, X86_EDI);
287 /* *(lmf) = previous_lmf */
288 x86_mov_membase_reg (buf, X86_EDI, 0, X86_EBX, 4);
289 /* discard method info */
290 x86_pop_reg (buf, X86_ESI);
291 /* restore caller saved regs */
292 x86_pop_reg (buf, X86_EBX);
293 x86_pop_reg (buf, X86_EDI);
294 x86_pop_reg (buf, X86_ESI);
295 x86_pop_reg (buf, X86_EBP);
297 /* discard save IP */
298 x86_alu_reg_imm (buf, X86_ADD, X86_ESP, 4);
299 /* restore LMF end */
301 /* Restore caller saved registers */
302 x86_mov_reg_membase (buf, X86_ECX, X86_ESP, 1 * 4, 4);
303 x86_mov_reg_membase (buf, X86_EDX, X86_ESP, 2 * 4, 4);
305 /* Pop saved reg array + method ptr */
306 x86_alu_reg_imm (buf, X86_ADD, X86_ESP, 9 * 4);
308 if (tramp_type == MONO_TRAMPOLINE_CLASS_INIT)
311 /* call the compiled method */
312 x86_jump_reg (buf, X86_EAX);
314 g_assert ((buf - code) <= 256);
316 if (tramp_type == MONO_TRAMPOLINE_CLASS_INIT) {
317 /* Initialize the nullified class init trampoline used in the AOT case */
318 nullified_class_init_trampoline = buf = mono_global_codeman_reserve (16);
325 #define TRAMPOLINE_SIZE 10
328 mono_arch_create_specific_trampoline (gpointer arg1, MonoTrampolineType tramp_type, MonoDomain *domain, guint32 *code_len)
330 guint8 *code, *buf, *tramp;
332 tramp = mono_get_trampoline_code (tramp_type);
334 mono_domain_lock (domain);
335 code = buf = mono_code_manager_reserve (domain->code_mp, TRAMPOLINE_SIZE);
336 mono_domain_unlock (domain);
338 x86_push_imm (buf, arg1);
339 x86_jump_code (buf, tramp);
340 g_assert ((buf - code) <= TRAMPOLINE_SIZE);
342 mono_arch_flush_icache (code, buf - code);
344 mono_jit_stats.method_trampolines++;
347 *code_len = buf - code;
353 mono_arch_invalidate_method (MonoJitInfo *ji, void *func, gpointer func_arg)
355 /* FIXME: This is not thread safe */
356 guint8 *code = ji->code_start;
358 x86_push_imm (code, func_arg);
359 x86_call_code (code, (guint8*)func);
363 * This method is only called when running in the Mono Debugger.
366 mono_debugger_create_notification_function ()
370 code = buf = mono_global_codeman_reserve (2);
371 x86_breakpoint (buf);