2 * tramp-arm.c: JIT trampoline code for ARM
5 * Paolo Molaro (lupus@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/arm/arm-codegen.h>
21 static guint8* nullified_class_init_trampoline;
24 * Return the instruction to jump from code to target, 0 if not
25 * reachable with a single instruction
28 branch_for_target_reachable (guint8 *branch, guint8 *target)
30 gint diff = target - branch - 8;
31 g_assert ((diff & 3) == 0);
34 return (ARMCOND_AL << ARMCOND_SHIFT) | (ARM_BR_TAG) | (diff >> 2);
36 /* diff between 0 and -33554432 */
37 if (diff >= -33554432)
38 return (ARMCOND_AL << ARMCOND_SHIFT) | (ARM_BR_TAG) | ((diff >> 2) & ~0xff000000);
44 * mono_arch_get_unbox_trampoline:
45 * @gsctx: the generic sharing context
47 * @addr: pointer to native code for @m
49 * when value type methods are called through the vtable we need to unbox the
50 * this argument. This method returns a pointer to a trampoline which does
51 * unboxing before calling the method
54 mono_arch_get_unbox_trampoline (MonoGenericSharingContext *gsctx, MonoMethod *m, gpointer addr)
58 MonoDomain *domain = mono_domain_get ();
60 if (MONO_TYPE_ISSTRUCT (mono_method_signature (m)->ret))
63 mono_domain_lock (domain);
64 start = code = mono_code_manager_reserve (domain->code_mp, 16);
65 mono_domain_unlock (domain);
67 ARM_LDR_IMM (code, ARMREG_IP, ARMREG_PC, 4);
68 ARM_ADD_REG_IMM8 (code, this_pos, this_pos, sizeof (MonoObject));
69 ARM_MOV_REG_REG (code, ARMREG_PC, ARMREG_IP);
70 *(guint32*)code = (guint32)addr;
72 mono_arch_flush_icache (start, code - start);
73 g_assert ((code - start) <= 16);
74 /*g_print ("unbox trampoline at %d for %s:%s\n", this_pos, m->klass->name, m->name);
75 g_print ("unbox code is at %p for method at %p\n", start, addr);*/
81 mono_arch_patch_callsite (guint8 *method_start, guint8 *code_ptr, guint8 *addr)
83 guint32 *code = (guint32*)code_ptr;
85 /* This is the 'bl' or the 'mov pc' instruction */
89 * Note that methods are called also with the bl opcode.
91 if ((((*code) >> 25) & 7) == 5) {
92 /*g_print ("direct patching\n");*/
93 arm_patch ((guint8*)code, addr);
94 mono_arch_flush_icache ((guint8*)code, 4);
98 if ((((*code) >> 20) & 0xFF) == 0x12) {
99 /*g_print ("patching bx\n");*/
100 arm_patch ((guint8*)code, addr);
101 mono_arch_flush_icache ((guint8*)(code - 2), 4);
105 g_assert_not_reached ();
109 mono_arch_patch_plt_entry (guint8 *code, guint8 *addr)
111 /* Patch the jump table entry used by the plt entry */
112 guint32 offset = ((guint32*)code)[3];
113 guint8 *jump_entry = code + offset + 16;
115 *(guint8**)jump_entry = addr;
119 mono_arch_nullify_class_init_trampoline (guint8 *code, gssize *regs)
125 mono_arch_nullify_plt_entry (guint8 *code)
127 if (mono_aot_only && !nullified_class_init_trampoline)
128 nullified_class_init_trampoline = mono_aot_get_named_code ("nullified_class_init_trampoline");
130 mono_arch_patch_plt_entry (code, nullified_class_init_trampoline);
133 /* Stack size for trampoline function
135 #define STACK (sizeof (MonoLMF))
137 /* Method-specific trampoline code fragment size */
138 #define METHOD_TRAMPOLINE_SIZE 64
140 /* Jump-specific trampoline code fragment size */
141 #define JUMP_TRAMPOLINE_SIZE 64
143 #define GEN_TRAMP_SIZE 192
146 * Stack frame description when the generic trampoline is called.
148 * ------------------- old sp
150 * ------------------- sp
153 mono_arch_create_trampoline_code (MonoTrampolineType tramp_type)
158 return mono_arch_create_trampoline_code_full (tramp_type, &code_size, &ji, FALSE);
162 mono_arch_create_trampoline_code_full (MonoTrampolineType tramp_type, guint32 *code_size, MonoJumpInfo **ji, gboolean aot)
164 guint8 *buf, *code = NULL;
165 guint8 *load_get_lmf_addr, *load_trampoline;
170 /* Now we'll create in 'buf' the ARM trampoline code. This
171 is the trampoline code common to all methods */
173 code = buf = mono_global_codeman_reserve (GEN_TRAMP_SIZE);
176 * At this point lr points to the specific arg and sp points to the saved
177 * regs on the stack (all but PC and SP). The original LR value has been
178 * saved as sp + LR_OFFSET by the push in the specific trampoline
180 #define LR_OFFSET (sizeof (gpointer) * 13)
181 ARM_MOV_REG_REG (buf, ARMREG_V1, ARMREG_SP);
184 * The trampoline contains a pc-relative offset to the got slot where the
185 * value is stored. The offset can be found at [lr + 4].
187 ARM_LDR_IMM (buf, ARMREG_V2, ARMREG_LR, 4);
188 ARM_LDR_REG_REG (buf, ARMREG_V2, ARMREG_V2, ARMREG_LR);
190 ARM_LDR_IMM (buf, ARMREG_V2, ARMREG_LR, 0);
192 ARM_LDR_IMM (buf, ARMREG_V3, ARMREG_SP, LR_OFFSET);
194 /* ok, now we can continue with the MonoLMF setup, mostly untouched
195 * from emit_prolog in mini-arm.c
196 * This is a synthetized call to mono_get_lmf_addr ()
199 *ji = mono_patch_info_list_prepend (*ji, buf - code, MONO_PATCH_INFO_JIT_ICALL_ADDR, "mono_get_lmf_addr");
200 ARM_LDR_IMM (buf, ARMREG_R0, ARMREG_PC, 0);
202 *(gpointer*)buf = NULL;
204 ARM_LDR_REG_REG (buf, ARMREG_R0, ARMREG_PC, ARMREG_R0);
206 load_get_lmf_addr = buf;
209 ARM_MOV_REG_REG (buf, ARMREG_LR, ARMREG_PC);
210 ARM_MOV_REG_REG (buf, ARMREG_PC, ARMREG_R0);
212 /* we build the MonoLMF structure on the stack - see mini-arm.h
213 * The pointer to the struct is put in r1.
214 * the iregs array is already allocated on the stack by push.
216 ARM_SUB_REG_IMM8 (buf, ARMREG_SP, ARMREG_SP, sizeof (MonoLMF) - sizeof (guint) * 14);
217 ARM_ADD_REG_IMM8 (buf, ARMREG_R1, ARMREG_SP, STACK - sizeof (MonoLMF));
218 /* r0 is the result from mono_get_lmf_addr () */
219 ARM_STR_IMM (buf, ARMREG_R0, ARMREG_R1, G_STRUCT_OFFSET (MonoLMF, lmf_addr));
220 /* new_lmf->previous_lmf = *lmf_addr */
221 ARM_LDR_IMM (buf, ARMREG_R2, ARMREG_R0, G_STRUCT_OFFSET (MonoLMF, previous_lmf));
222 ARM_STR_IMM (buf, ARMREG_R2, ARMREG_R1, G_STRUCT_OFFSET (MonoLMF, previous_lmf));
223 /* *(lmf_addr) = r1 */
224 ARM_STR_IMM (buf, ARMREG_R1, ARMREG_R0, G_STRUCT_OFFSET (MonoLMF, previous_lmf));
225 /* save method info (it's in v2) */
226 if ((tramp_type == MONO_TRAMPOLINE_JIT) || (tramp_type == MONO_TRAMPOLINE_JUMP))
227 ARM_STR_IMM (buf, ARMREG_V2, ARMREG_R1, G_STRUCT_OFFSET (MonoLMF, method));
228 ARM_STR_IMM (buf, ARMREG_SP, ARMREG_R1, G_STRUCT_OFFSET (MonoLMF, ebp));
229 /* save the IP (caller ip) */
230 if (tramp_type == MONO_TRAMPOLINE_JUMP) {
231 ARM_MOV_REG_IMM8 (buf, ARMREG_R2, 0);
233 /* assumes STACK == sizeof (MonoLMF) */
234 ARM_LDR_IMM (buf, ARMREG_R2, ARMREG_SP, (G_STRUCT_OFFSET (MonoLMF, iregs) + 13*4));
236 ARM_STR_IMM (buf, ARMREG_R2, ARMREG_R1, G_STRUCT_OFFSET (MonoLMF, eip));
239 * Now we're ready to call xxx_trampoline ().
241 /* Arg 1: the saved registers. It was put in v1 */
242 ARM_MOV_REG_REG (buf, ARMREG_R0, ARMREG_V1);
244 /* Arg 2: code (next address to the instruction that called us) */
245 if (tramp_type == MONO_TRAMPOLINE_JUMP) {
246 ARM_MOV_REG_IMM8 (buf, ARMREG_R1, 0);
248 ARM_MOV_REG_REG (buf, ARMREG_R1, ARMREG_V3);
251 /* Arg 3: the specific argument, stored in v2
253 ARM_MOV_REG_REG (buf, ARMREG_R2, ARMREG_V2);
256 char *icall_name = g_strdup_printf ("trampoline_func_%d", tramp_type);
257 *ji = mono_patch_info_list_prepend (*ji, buf - code, MONO_PATCH_INFO_JIT_ICALL_ADDR, icall_name);
258 ARM_LDR_IMM (buf, ARMREG_IP, ARMREG_PC, 0);
260 *(gpointer*)buf = NULL;
262 ARM_LDR_REG_REG (buf, ARMREG_IP, ARMREG_PC, ARMREG_IP);
264 load_trampoline = buf;
268 ARM_MOV_REG_REG (buf, ARMREG_LR, ARMREG_PC);
269 ARM_MOV_REG_REG (buf, ARMREG_PC, ARMREG_IP);
271 /* OK, code address is now on r0. Move it to the place on the stack
272 * where IP was saved (it is now no more useful to us and it can be
273 * clobbered). This way we can just restore all the regs in one inst
276 ARM_STR_IMM (buf, ARMREG_R0, ARMREG_V1, (ARMREG_R12 * 4));
278 /* Check for thread interruption */
279 /* This is not perf critical code so no need to check the interrupt flag */
281 * Have to call the _force_ variant, since there could be a protected wrapper on the top of the stack.
284 *ji = mono_patch_info_list_prepend (*ji, buf - code, MONO_PATCH_INFO_JIT_ICALL_ADDR, "mono_thread_force_interruption_checkpoint");
285 ARM_LDR_IMM (buf, ARMREG_IP, ARMREG_PC, 0);
287 *(gpointer*)buf = NULL;
289 ARM_LDR_REG_REG (buf, ARMREG_IP, ARMREG_PC, ARMREG_IP);
291 ARM_LDR_IMM (buf, ARMREG_IP, ARMREG_PC, 0);
293 *(gpointer*)buf = mono_thread_force_interruption_checkpoint;
296 ARM_MOV_REG_REG (buf, ARMREG_LR, ARMREG_PC);
297 ARM_MOV_REG_REG (buf, ARMREG_PC, ARMREG_IP);
300 * Now we restore the MonoLMF (see emit_epilogue in mini-arm.c)
301 * and the rest of the registers, so the method called will see
302 * the same state as before we executed.
303 * The pointer to MonoLMF is in r2.
305 ARM_MOV_REG_REG (buf, ARMREG_R2, ARMREG_SP);
306 /* ip = previous_lmf */
307 ARM_LDR_IMM (buf, ARMREG_IP, ARMREG_R2, G_STRUCT_OFFSET (MonoLMF, previous_lmf));
309 ARM_LDR_IMM (buf, ARMREG_LR, ARMREG_R2, G_STRUCT_OFFSET (MonoLMF, lmf_addr));
310 /* *(lmf_addr) = previous_lmf */
311 ARM_STR_IMM (buf, ARMREG_IP, ARMREG_LR, G_STRUCT_OFFSET (MonoLMF, previous_lmf));
313 /* Non-standard function epilogue. Instead of doing a proper
314 * return, we just jump to the compiled code.
316 /* Restore the registers and jump to the code:
317 * Note that IP has been conveniently set to the method addr.
319 ARM_ADD_REG_IMM8 (buf, ARMREG_SP, ARMREG_SP, sizeof (MonoLMF) - sizeof (guint) * 14);
320 ARM_POP_NWB (buf, 0x5fff);
321 /* do we need to set sp? */
322 ARM_ADD_REG_IMM8 (buf, ARMREG_SP, ARMREG_SP, (14 * 4));
323 if (tramp_type == MONO_TRAMPOLINE_CLASS_INIT)
324 ARM_MOV_REG_REG (buf, ARMREG_PC, ARMREG_LR);
326 ARM_MOV_REG_REG (buf, ARMREG_PC, ARMREG_IP);
328 constants = (gpointer*)buf;
329 constants [0] = mono_get_lmf_addr;
330 constants [1] = (gpointer)mono_get_trampoline_func (tramp_type);
333 /* backpatch by emitting the missing instructions skipped above */
334 ARM_LDR_IMM (load_get_lmf_addr, ARMREG_R0, ARMREG_PC, (buf - load_get_lmf_addr - 8));
335 ARM_LDR_IMM (load_trampoline, ARMREG_IP, ARMREG_PC, (buf + 4 - load_trampoline - 8));
340 /* Flush instruction cache, since we've generated code */
341 mono_arch_flush_icache (code, buf - code);
344 g_assert ((buf - code) <= GEN_TRAMP_SIZE);
346 *code_size = buf - code;
348 if (tramp_type == MONO_TRAMPOLINE_CLASS_INIT) {
351 /* Initialize the nullified class init trampoline used in the AOT case */
352 nullified_class_init_trampoline = mono_arch_get_nullified_class_init_trampoline (&code_len);
359 mono_arch_get_nullified_class_init_trampoline (guint32 *code_len)
363 code = buf = mono_global_codeman_reserve (16);
365 ARM_MOV_REG_REG (buf, ARMREG_PC, ARMREG_LR);
367 mono_arch_flush_icache (code, buf - code);
369 *code_len = buf - code;
374 #define SPEC_TRAMP_SIZE 24
377 mono_arch_create_specific_trampoline (gpointer arg1, MonoTrampolineType tramp_type, MonoDomain *domain, guint32 *code_len)
379 guint8 *code, *buf, *tramp;
381 guint32 short_branch, size = SPEC_TRAMP_SIZE;
383 tramp = mono_get_trampoline_code (tramp_type);
385 mono_domain_lock (domain);
386 code = buf = mono_code_manager_reserve_align (domain->code_mp, size, 4);
387 if ((short_branch = branch_for_target_reachable (code + 8, tramp))) {
389 mono_code_manager_commit (domain->code_mp, code, SPEC_TRAMP_SIZE, size);
391 mono_domain_unlock (domain);
393 /* we could reduce this to 12 bytes if tramp is within reach:
397 * The called code can access method using the lr register
398 * A 20 byte sequence could be:
400 * ARM_MOV_REG_REG (lr, pc)
401 * ARM_LDR_IMM (pc, pc, 0)
405 /* We save all the registers, except PC and SP */
406 ARM_PUSH (buf, 0x5fff);
408 constants = (gpointer*)buf;
409 constants [0] = GUINT_TO_POINTER (short_branch | (1 << 24));
410 constants [1] = arg1;
413 ARM_LDR_IMM (buf, ARMREG_R1, ARMREG_PC, 8); /* temp reg */
414 ARM_MOV_REG_REG (buf, ARMREG_LR, ARMREG_PC);
415 ARM_MOV_REG_REG (buf, ARMREG_PC, ARMREG_R1);
417 constants = (gpointer*)buf;
418 constants [0] = arg1;
419 constants [1] = tramp;
423 /* Flush instruction cache, since we've generated code */
424 mono_arch_flush_icache (code, buf - code);
426 g_assert ((buf - code) <= size);
429 *code_len = buf - code;
435 mono_arch_create_rgctx_lazy_fetch_trampoline (guint32 encoded_offset)
437 /* FIXME: implement! */
438 g_assert_not_reached ();
443 mono_arch_get_rgctx_lazy_fetch_offset (gpointer *regs)
445 /* FIXME: implement! */
446 g_assert_not_reached ();