1 /* -----------------------------------------------------------------------
2 ffi.c - Copyright (c) 2002, 2007 Bo Thorsen <bo@suse.de>
4 x86-64 Foreign Function Interface
6 Permission is hereby granted, free of charge, to any person obtaining
7 a copy of this software and associated documentation files (the
8 ``Software''), to deal in the Software without restriction, including
9 without limitation the rights to use, copy, modify, merge, publish,
10 distribute, sublicense, and/or sell copies of the Software, and to
11 permit persons to whom the Software is furnished to do so, subject to
12 the following conditions:
14 The above copyright notice and this permission notice shall be included
15 in all copies or substantial portions of the Software.
17 THE SOFTWARE IS PROVIDED ``AS IS'', WITHOUT WARRANTY OF ANY KIND, EXPRESS
18 OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
19 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
20 IN NO EVENT SHALL CYGNUS SOLUTIONS BE LIABLE FOR ANY CLAIM, DAMAGES OR
21 OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
22 ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
23 OTHER DEALINGS IN THE SOFTWARE.
24 ----------------------------------------------------------------------- */
27 #include <ffi_common.h>
34 #define MAX_GPR_REGS 6
35 #define MAX_SSE_REGS 8
39 /* Registers for argument passing. */
40 UINT64 gpr[MAX_GPR_REGS];
41 __int128_t sse[MAX_SSE_REGS];
44 extern void ffi_call_unix64 (void *args, unsigned long bytes, unsigned flags,
45 void *raddr, void (*fnaddr)(), unsigned ssecount);
47 /* All reference to register classes here is identical to the code in
48 gcc/config/i386/i386.c. Do *not* change one without the other. */
50 /* Register class used for passing given 64bit part of the argument.
51 These represent classes as documented by the PS ABI, with the exception
52 of SSESF, SSEDF classes, that are basically SSE class, just gcc will
53 use SF or DFmode move instead of DImode to avoid reformating penalties.
55 Similary we play games with INTEGERSI_CLASS to use cheaper SImode moves
56 whenever possible (upper half does contain padding). */
61 X86_64_INTEGERSI_CLASS,
68 X86_64_COMPLEX_X87_CLASS,
74 #define SSE_CLASS_P(X) ((X) >= X86_64_SSE_CLASS && X <= X86_64_SSEUP_CLASS)
76 /* x86-64 register passing implementation. See x86-64 ABI for details. Goal
77 of this code is to classify each 8bytes of incoming argument by the register
78 class and assign registers accordingly. */
80 /* Return the union class of CLASS1 and CLASS2.
81 See the x86-64 PS ABI for details. */
83 static enum x86_64_reg_class
84 merge_classes (enum x86_64_reg_class class1, enum x86_64_reg_class class2)
86 /* Rule #1: If both classes are equal, this is the resulting class. */
90 /* Rule #2: If one of the classes is NO_CLASS, the resulting class is
92 if (class1 == X86_64_NO_CLASS)
94 if (class2 == X86_64_NO_CLASS)
97 /* Rule #3: If one of the classes is MEMORY, the result is MEMORY. */
98 if (class1 == X86_64_MEMORY_CLASS || class2 == X86_64_MEMORY_CLASS)
99 return X86_64_MEMORY_CLASS;
101 /* Rule #4: If one of the classes is INTEGER, the result is INTEGER. */
102 if ((class1 == X86_64_INTEGERSI_CLASS && class2 == X86_64_SSESF_CLASS)
103 || (class2 == X86_64_INTEGERSI_CLASS && class1 == X86_64_SSESF_CLASS))
104 return X86_64_INTEGERSI_CLASS;
105 if (class1 == X86_64_INTEGER_CLASS || class1 == X86_64_INTEGERSI_CLASS
106 || class2 == X86_64_INTEGER_CLASS || class2 == X86_64_INTEGERSI_CLASS)
107 return X86_64_INTEGER_CLASS;
109 /* Rule #5: If one of the classes is X87, X87UP, or COMPLEX_X87 class,
111 if (class1 == X86_64_X87_CLASS
112 || class1 == X86_64_X87UP_CLASS
113 || class1 == X86_64_COMPLEX_X87_CLASS
114 || class2 == X86_64_X87_CLASS
115 || class2 == X86_64_X87UP_CLASS
116 || class2 == X86_64_COMPLEX_X87_CLASS)
117 return X86_64_MEMORY_CLASS;
119 /* Rule #6: Otherwise class SSE is used. */
120 return X86_64_SSE_CLASS;
123 /* Classify the argument of type TYPE and mode MODE.
124 CLASSES will be filled by the register class used to pass each word
125 of the operand. The number of words is returned. In case the parameter
126 should be passed in memory, 0 is returned. As a special case for zero
127 sized containers, classes[0] will be NO_CLASS and 1 is returned.
129 See the x86-64 PS ABI for details.
132 classify_argument (ffi_type *type, enum x86_64_reg_class classes[],
139 case FFI_TYPE_UINT16:
140 case FFI_TYPE_SINT16:
141 case FFI_TYPE_UINT32:
142 case FFI_TYPE_SINT32:
143 case FFI_TYPE_UINT64:
144 case FFI_TYPE_SINT64:
145 case FFI_TYPE_POINTER:
146 if (byte_offset + type->size <= 4)
147 classes[0] = X86_64_INTEGERSI_CLASS;
149 classes[0] = X86_64_INTEGER_CLASS;
152 if (byte_offset == 0)
153 classes[0] = X86_64_SSESF_CLASS;
155 classes[0] = X86_64_SSE_CLASS;
157 case FFI_TYPE_DOUBLE:
158 classes[0] = X86_64_SSEDF_CLASS;
160 case FFI_TYPE_LONGDOUBLE:
161 classes[0] = X86_64_X87_CLASS;
162 classes[1] = X86_64_X87UP_CLASS;
164 case FFI_TYPE_STRUCT:
166 const int UNITS_PER_WORD = 8;
167 int words = (type->size + UNITS_PER_WORD - 1) / UNITS_PER_WORD;
170 enum x86_64_reg_class subclasses[MAX_CLASSES];
172 /* If the struct is larger than 16 bytes, pass it on the stack. */
176 for (i = 0; i < words; i++)
177 classes[i] = X86_64_NO_CLASS;
179 /* Merge the fields of structure. */
180 for (ptr = type->elements; *ptr != NULL; ptr++)
184 byte_offset = ALIGN (byte_offset, (*ptr)->alignment);
186 num = classify_argument (*ptr, subclasses, byte_offset % 8);
189 for (i = 0; i < num; i++)
191 int pos = byte_offset / 8;
193 merge_classes (subclasses[i], classes[i + pos]);
196 byte_offset += (*ptr)->size;
199 /* Final merger cleanup. */
200 for (i = 0; i < words; i++)
202 /* If one class is MEMORY, everything should be passed in
204 if (classes[i] == X86_64_MEMORY_CLASS)
207 /* The X86_64_SSEUP_CLASS should be always preceded by
209 if (classes[i] == X86_64_SSEUP_CLASS
210 && (i == 0 || classes[i - 1] != X86_64_SSE_CLASS))
211 classes[i] = X86_64_SSE_CLASS;
213 /* X86_64_X87UP_CLASS should be preceded by X86_64_X87_CLASS. */
214 if (classes[i] == X86_64_X87UP_CLASS
215 && (i == 0 || classes[i - 1] != X86_64_X87_CLASS))
216 classes[i] = X86_64_SSE_CLASS;
224 return 0; /* Never reached. */
227 /* Examine the argument and return set number of register required in each
228 class. Return zero iff parameter should be passed in memory, otherwise
229 the number of registers. */
232 examine_argument (ffi_type *type, enum x86_64_reg_class classes[MAX_CLASSES],
233 _Bool in_return, int *pngpr, int *pnsse)
235 int i, n, ngpr, nsse;
237 n = classify_argument (type, classes, 0);
242 for (i = 0; i < n; ++i)
245 case X86_64_INTEGER_CLASS:
246 case X86_64_INTEGERSI_CLASS:
249 case X86_64_SSE_CLASS:
250 case X86_64_SSESF_CLASS:
251 case X86_64_SSEDF_CLASS:
254 case X86_64_NO_CLASS:
255 case X86_64_SSEUP_CLASS:
257 case X86_64_X87_CLASS:
258 case X86_64_X87UP_CLASS:
259 case X86_64_COMPLEX_X87_CLASS:
260 return in_return != 0;
271 /* Perform machine dependent cif processing. */
274 ffi_prep_cif_machdep (ffi_cif *cif)
276 int gprcount, ssecount, i, avn, n, ngpr, nsse, flags;
277 enum x86_64_reg_class classes[MAX_CLASSES];
280 gprcount = ssecount = 0;
282 flags = cif->rtype->type;
283 if (flags != FFI_TYPE_VOID)
285 n = examine_argument (cif->rtype, classes, 1, &ngpr, &nsse);
288 /* The return value is passed in memory. A pointer to that
289 memory is the first argument. Allocate a register for it. */
291 /* We don't have to do anything in asm for the return. */
292 flags = FFI_TYPE_VOID;
294 else if (flags == FFI_TYPE_STRUCT)
296 /* Mark which registers the result appears in. */
297 _Bool sse0 = SSE_CLASS_P (classes[0]);
298 _Bool sse1 = n == 2 && SSE_CLASS_P (classes[1]);
301 else if (!sse0 && sse1)
303 else if (sse0 && sse1)
305 /* Mark the true size of the structure. */
306 flags |= cif->rtype->size << 12;
310 /* Go over all arguments and determine the way they should be passed.
311 If it's in a register and there is space for it, let that be so. If
312 not, add it's size to the stack byte count. */
313 for (bytes = 0, i = 0, avn = cif->nargs; i < avn; i++)
315 if (examine_argument (cif->arg_types[i], classes, 0, &ngpr, &nsse) == 0
316 || gprcount + ngpr > MAX_GPR_REGS
317 || ssecount + nsse > MAX_SSE_REGS)
319 long align = cif->arg_types[i]->alignment;
324 bytes = ALIGN(bytes, align);
325 bytes += cif->arg_types[i]->size;
342 ffi_call (ffi_cif *cif, void (*fn)(), void *rvalue, void **avalue)
344 enum x86_64_reg_class classes[MAX_CLASSES];
346 ffi_type **arg_types;
347 int gprcount, ssecount, ngpr, nsse, i, avn;
349 struct register_args *reg_args;
351 /* Can't call 32-bit mode from 64-bit mode. */
352 FFI_ASSERT (cif->abi == FFI_UNIX64);
354 /* If the return value is a struct and we don't have a return value
355 address then we need to make one. Note the setting of flags to
356 VOID above in ffi_prep_cif_machdep. */
357 ret_in_memory = (cif->rtype->type == FFI_TYPE_STRUCT
358 && (cif->flags & 0xff) == FFI_TYPE_VOID);
359 if (rvalue == NULL && ret_in_memory)
360 rvalue = alloca (cif->rtype->size);
362 /* Allocate the space for the arguments, plus 4 words of temp space. */
363 stack = alloca (sizeof (struct register_args) + cif->bytes + 4*8);
364 reg_args = (struct register_args *) stack;
365 argp = stack + sizeof (struct register_args);
367 gprcount = ssecount = 0;
369 /* If the return value is passed in memory, add the pointer as the
370 first integer argument. */
372 reg_args->gpr[gprcount++] = (long) rvalue;
375 arg_types = cif->arg_types;
377 for (i = 0; i < avn; ++i)
379 size_t size = arg_types[i]->size;
382 n = examine_argument (arg_types[i], classes, 0, &ngpr, &nsse);
384 || gprcount + ngpr > MAX_GPR_REGS
385 || ssecount + nsse > MAX_SSE_REGS)
387 long align = arg_types[i]->alignment;
389 /* Stack arguments are *always* at least 8 byte aligned. */
393 /* Pass this argument in memory. */
394 argp = (void *) ALIGN (argp, align);
395 memcpy (argp, avalue[i], size);
400 /* The argument is passed entirely in registers. */
401 char *a = (char *) avalue[i];
404 for (j = 0; j < n; j++, a += 8, size -= 8)
408 case X86_64_INTEGER_CLASS:
409 case X86_64_INTEGERSI_CLASS:
410 reg_args->gpr[gprcount] = 0;
411 memcpy (®_args->gpr[gprcount], a, size < 8 ? size : 8);
414 case X86_64_SSE_CLASS:
415 case X86_64_SSEDF_CLASS:
416 reg_args->sse[ssecount++] = *(UINT64 *) a;
418 case X86_64_SSESF_CLASS:
419 reg_args->sse[ssecount++] = *(UINT32 *) a;
428 ffi_call_unix64 (stack, cif->bytes + sizeof (struct register_args),
429 cif->flags, rvalue, fn, ssecount);
433 extern void ffi_closure_unix64(void);
436 ffi_prep_closure_loc (ffi_closure* closure,
438 void (*fun)(ffi_cif*, void*, void**, void*),
442 volatile unsigned short *tramp;
444 tramp = (volatile unsigned short *) &closure->tramp[0];
446 tramp[0] = 0xbb49; /* mov <code>, %r11 */
447 *(void * volatile *) &tramp[1] = ffi_closure_unix64;
448 tramp[5] = 0xba49; /* mov <data>, %r10 */
449 *(void * volatile *) &tramp[6] = codeloc;
451 /* Set the carry bit iff the function uses any sse registers.
452 This is clc or stc, together with the first byte of the jmp. */
453 tramp[10] = cif->flags & (1 << 11) ? 0x49f9 : 0x49f8;
455 tramp[11] = 0xe3ff; /* jmp *%r11 */
459 closure->user_data = user_data;
465 ffi_closure_unix64_inner(ffi_closure *closure, void *rvalue,
466 struct register_args *reg_args, char *argp)
470 ffi_type **arg_types;
472 int gprcount, ssecount, ngpr, nsse;
476 avalue = alloca(cif->nargs * sizeof(void *));
477 gprcount = ssecount = 0;
479 ret = cif->rtype->type;
480 if (ret != FFI_TYPE_VOID)
482 enum x86_64_reg_class classes[MAX_CLASSES];
483 int n = examine_argument (cif->rtype, classes, 1, &ngpr, &nsse);
486 /* The return value goes in memory. Arrange for the closure
487 return value to go directly back to the original caller. */
488 rvalue = (void *) reg_args->gpr[gprcount++];
489 /* We don't have to do anything in asm for the return. */
492 else if (ret == FFI_TYPE_STRUCT && n == 2)
494 /* Mark which register the second word of the structure goes in. */
495 _Bool sse0 = SSE_CLASS_P (classes[0]);
496 _Bool sse1 = SSE_CLASS_P (classes[1]);
499 else if (sse0 && !sse1)
505 arg_types = cif->arg_types;
507 for (i = 0; i < avn; ++i)
509 enum x86_64_reg_class classes[MAX_CLASSES];
512 n = examine_argument (arg_types[i], classes, 0, &ngpr, &nsse);
514 || gprcount + ngpr > MAX_GPR_REGS
515 || ssecount + nsse > MAX_SSE_REGS)
517 long align = arg_types[i]->alignment;
519 /* Stack arguments are *always* at least 8 byte aligned. */
523 /* Pass this argument in memory. */
524 argp = (void *) ALIGN (argp, align);
526 argp += arg_types[i]->size;
528 /* If the argument is in a single register, or two consecutive
529 registers, then we can use that address directly. */
532 && SSE_CLASS_P (classes[0]) == SSE_CLASS_P (classes[1])))
534 /* The argument is in a single register. */
535 if (SSE_CLASS_P (classes[0]))
537 avalue[i] = ®_args->sse[ssecount];
542 avalue[i] = ®_args->gpr[gprcount];
546 /* Otherwise, allocate space to make them consecutive. */
549 char *a = alloca (16);
553 for (j = 0; j < n; j++, a += 8)
555 if (SSE_CLASS_P (classes[j]))
556 memcpy (a, ®_args->sse[ssecount++], 8);
558 memcpy (a, ®_args->gpr[gprcount++], 8);
563 /* Invoke the closure. */
564 closure->fun (cif, rvalue, avalue, closure->user_data);
566 /* Tell assembly how to perform return type promotions. */
570 #endif /* __x86_64__ */