xref: /illumos-gate/usr/src/lib/libdtrace/common/dt_cg.c (revision 78a2e113edb6fe0a0382b403b55d92e8f0bba78f)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 
23 /*
24  * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
25  * Use is subject to license terms.
26  */
27 
28 /*
29  * Copyright (c) 2012 by Delphix. All rights reserved.
30  * Copyright 2017 Joyent, Inc.
31  */
32 
33 #include <sys/types.h>
34 #include <sys/sysmacros.h>
35 #include <sys/isa_defs.h>
36 
37 #include <strings.h>
38 #include <stdlib.h>
39 #include <setjmp.h>
40 #include <assert.h>
41 #include <errno.h>
42 
43 #include <dt_impl.h>
44 #include <dt_grammar.h>
45 #include <dt_parser.h>
46 #include <dt_provider.h>
47 
48 static void dt_cg_node(dt_node_t *, dt_irlist_t *, dt_regset_t *);
49 
50 static dt_irnode_t *
51 dt_cg_node_alloc(uint_t label, dif_instr_t instr)
52 {
53 	dt_irnode_t *dip = malloc(sizeof (dt_irnode_t));
54 
55 	if (dip == NULL)
56 		longjmp(yypcb->pcb_jmpbuf, EDT_NOMEM);
57 
58 	dip->di_label = label;
59 	dip->di_instr = instr;
60 	dip->di_extern = NULL;
61 	dip->di_next = NULL;
62 
63 	return (dip);
64 }
65 
66 /*
67  * Code generator wrapper function for ctf_member_info.  If we are given a
68  * reference to a forward declaration tag, search the entire type space for
69  * the actual definition and then call ctf_member_info on the result.
70  */
71 static ctf_file_t *
72 dt_cg_membinfo(ctf_file_t *fp, ctf_id_t type, const char *s, ctf_membinfo_t *mp)
73 {
74 	while (ctf_type_kind(fp, type) == CTF_K_FORWARD) {
75 		char n[DT_TYPE_NAMELEN];
76 		dtrace_typeinfo_t dtt;
77 
78 		if (ctf_type_name(fp, type, n, sizeof (n)) == NULL ||
79 		    dt_type_lookup(n, &dtt) == -1 || (
80 		    dtt.dtt_ctfp == fp && dtt.dtt_type == type))
81 			break; /* unable to improve our position */
82 
83 		fp = dtt.dtt_ctfp;
84 		type = ctf_type_resolve(fp, dtt.dtt_type);
85 	}
86 
87 	if (ctf_member_info(fp, type, s, mp) == CTF_ERR)
88 		return (NULL); /* ctf_errno is set for us */
89 
90 	return (fp);
91 }
92 
93 static void
94 dt_cg_xsetx(dt_irlist_t *dlp, dt_ident_t *idp, uint_t lbl, int reg, uint64_t x)
95 {
96 	int flag = idp != NULL ? DT_INT_PRIVATE : DT_INT_SHARED;
97 	int intoff = dt_inttab_insert(yypcb->pcb_inttab, x, flag);
98 	dif_instr_t instr = DIF_INSTR_SETX((uint_t)intoff, reg);
99 
100 	if (intoff == -1)
101 		longjmp(yypcb->pcb_jmpbuf, EDT_NOMEM);
102 
103 	if (intoff > DIF_INTOFF_MAX)
104 		longjmp(yypcb->pcb_jmpbuf, EDT_INT2BIG);
105 
106 	dt_irlist_append(dlp, dt_cg_node_alloc(lbl, instr));
107 
108 	if (idp != NULL)
109 		dlp->dl_last->di_extern = idp;
110 }
111 
112 static void
113 dt_cg_setx(dt_irlist_t *dlp, int reg, uint64_t x)
114 {
115 	dt_cg_xsetx(dlp, NULL, DT_LBL_NONE, reg, x);
116 }
117 
118 /*
119  * When loading bit-fields, we want to convert a byte count in the range
120  * 1-8 to the closest power of 2 (e.g. 3->4, 5->8, etc).  The clp2() function
121  * is a clever implementation from "Hacker's Delight" by Henry Warren, Jr.
122  */
123 static size_t
124 clp2(size_t x)
125 {
126 	x--;
127 
128 	x |= (x >> 1);
129 	x |= (x >> 2);
130 	x |= (x >> 4);
131 	x |= (x >> 8);
132 	x |= (x >> 16);
133 
134 	return (x + 1);
135 }
136 
137 /*
138  * Lookup the correct load opcode to use for the specified node and CTF type.
139  * We determine the size and convert it to a 3-bit index.  Our lookup table
140  * is constructed to use a 5-bit index, consisting of the 3-bit size 0-7, a
141  * bit for the sign, and a bit for userland address.  For example, a 4-byte
142  * signed load from userland would be at the following table index:
143  * user=1 sign=1 size=4 => binary index 11011 = decimal index 27
144  */
145 static uint_t
146 dt_cg_load(dt_node_t *dnp, ctf_file_t *ctfp, ctf_id_t type)
147 {
148 	static const uint_t ops[] = {
149 		DIF_OP_LDUB,	DIF_OP_LDUH,	0,	DIF_OP_LDUW,
150 		0,		0,		0,	DIF_OP_LDX,
151 		DIF_OP_LDSB,	DIF_OP_LDSH,	0,	DIF_OP_LDSW,
152 		0,		0,		0,	DIF_OP_LDX,
153 		DIF_OP_ULDUB,	DIF_OP_ULDUH,	0,	DIF_OP_ULDUW,
154 		0,		0,		0,	DIF_OP_ULDX,
155 		DIF_OP_ULDSB,	DIF_OP_ULDSH,	0,	DIF_OP_ULDSW,
156 		0,		0,		0,	DIF_OP_ULDX,
157 	};
158 
159 	ctf_encoding_t e;
160 	ssize_t size;
161 
162 	/*
163 	 * If we're loading a bit-field, the size of our load is found by
164 	 * rounding cte_bits up to a byte boundary and then finding the
165 	 * nearest power of two to this value (see clp2(), above).
166 	 */
167 	if ((dnp->dn_flags & DT_NF_BITFIELD) &&
168 	    ctf_type_encoding(ctfp, type, &e) != CTF_ERR)
169 		size = clp2(P2ROUNDUP(e.cte_bits, NBBY) / NBBY);
170 	else
171 		size = ctf_type_size(ctfp, type);
172 
173 	if (size < 1 || size > 8 || (size & (size - 1)) != 0) {
174 		xyerror(D_UNKNOWN, "internal error -- cg cannot load "
175 		    "size %ld when passed by value\n", (long)size);
176 	}
177 
178 	size--; /* convert size to 3-bit index */
179 
180 	if (dnp->dn_flags & DT_NF_SIGNED)
181 		size |= 0x08;
182 	if (dnp->dn_flags & DT_NF_USERLAND)
183 		size |= 0x10;
184 
185 	return (ops[size]);
186 }
187 
188 static void
189 dt_cg_ptrsize(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp,
190     uint_t op, int dreg)
191 {
192 	ctf_file_t *ctfp = dnp->dn_ctfp;
193 	ctf_arinfo_t r;
194 	dif_instr_t instr;
195 	ctf_id_t type;
196 	uint_t kind;
197 	ssize_t size;
198 	int sreg;
199 
200 	type = ctf_type_resolve(ctfp, dnp->dn_type);
201 	kind = ctf_type_kind(ctfp, type);
202 	assert(kind == CTF_K_POINTER || kind == CTF_K_ARRAY);
203 
204 	if (kind == CTF_K_ARRAY) {
205 		if (ctf_array_info(ctfp, type, &r) != 0) {
206 			yypcb->pcb_hdl->dt_ctferr = ctf_errno(ctfp);
207 			longjmp(yypcb->pcb_jmpbuf, EDT_CTF);
208 		}
209 		type = r.ctr_contents;
210 	} else
211 		type = ctf_type_reference(ctfp, type);
212 
213 	if ((size = ctf_type_size(ctfp, type)) == 1)
214 		return; /* multiply or divide by one can be omitted */
215 
216 	sreg = dt_regset_alloc(drp);
217 	dt_cg_setx(dlp, sreg, size);
218 	instr = DIF_INSTR_FMT(op, dreg, sreg, dreg);
219 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
220 	dt_regset_free(drp, sreg);
221 }
222 
223 /*
224  * If the result of a "." or "->" operation is a bit-field, we use this routine
225  * to generate an epilogue to the load instruction that extracts the value.  In
226  * the diagrams below the "ld??" is the load instruction that is generated to
227  * load the containing word that is generating prior to calling this function.
228  *
229  * Epilogue for unsigned fields:	Epilogue for signed fields:
230  *
231  * ldu?	[r1], r1			lds? [r1], r1
232  * setx	USHIFT, r2			setx 64 - SSHIFT, r2
233  * srl	r1, r2, r1			sll  r1, r2, r1
234  * setx	(1 << bits) - 1, r2		setx 64 - bits, r2
235  * and	r1, r2, r1			sra  r1, r2, r1
236  *
237  * The *SHIFT constants above changes value depending on the endian-ness of our
238  * target architecture.  Refer to the comments below for more details.
239  */
240 static void
241 dt_cg_field_get(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp,
242     ctf_file_t *fp, const ctf_membinfo_t *mp)
243 {
244 	ctf_encoding_t e;
245 	dif_instr_t instr;
246 	uint64_t shift;
247 	int r1, r2;
248 
249 	if (ctf_type_encoding(fp, mp->ctm_type, &e) != 0 || e.cte_bits > 64) {
250 		xyerror(D_UNKNOWN, "cg: bad field: off %lu type <%ld> "
251 		    "bits %u\n", mp->ctm_offset, mp->ctm_type, e.cte_bits);
252 	}
253 
254 	assert(dnp->dn_op == DT_TOK_PTR || dnp->dn_op == DT_TOK_DOT);
255 	r1 = dnp->dn_left->dn_reg;
256 	r2 = dt_regset_alloc(drp);
257 
258 	/*
259 	 * On little-endian architectures, ctm_offset counts from the right so
260 	 * ctm_offset % NBBY itself is the amount we want to shift right to
261 	 * move the value bits to the little end of the register to mask them.
262 	 * On big-endian architectures, ctm_offset counts from the left so we
263 	 * must subtract (ctm_offset % NBBY + cte_bits) from the size in bits
264 	 * we used for the load.  The size of our load in turn is found by
265 	 * rounding cte_bits up to a byte boundary and then finding the
266 	 * nearest power of two to this value (see clp2(), above).  These
267 	 * properties are used to compute shift as USHIFT or SSHIFT, below.
268 	 */
269 	if (dnp->dn_flags & DT_NF_SIGNED) {
270 #ifdef _BIG_ENDIAN
271 		shift = clp2(P2ROUNDUP(e.cte_bits, NBBY) / NBBY) * NBBY -
272 		    mp->ctm_offset % NBBY;
273 #else
274 		shift = mp->ctm_offset % NBBY + e.cte_bits;
275 #endif
276 		dt_cg_setx(dlp, r2, 64 - shift);
277 		instr = DIF_INSTR_FMT(DIF_OP_SLL, r1, r2, r1);
278 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
279 
280 		dt_cg_setx(dlp, r2, 64 - e.cte_bits);
281 		instr = DIF_INSTR_FMT(DIF_OP_SRA, r1, r2, r1);
282 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
283 	} else {
284 #ifdef _BIG_ENDIAN
285 		shift = clp2(P2ROUNDUP(e.cte_bits, NBBY) / NBBY) * NBBY -
286 		    (mp->ctm_offset % NBBY + e.cte_bits);
287 #else
288 		shift = mp->ctm_offset % NBBY;
289 #endif
290 		dt_cg_setx(dlp, r2, shift);
291 		instr = DIF_INSTR_FMT(DIF_OP_SRL, r1, r2, r1);
292 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
293 
294 		dt_cg_setx(dlp, r2, (1ULL << e.cte_bits) - 1);
295 		instr = DIF_INSTR_FMT(DIF_OP_AND, r1, r2, r1);
296 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
297 	}
298 
299 	dt_regset_free(drp, r2);
300 }
301 
302 /*
303  * If the destination of a store operation is a bit-field, we use this routine
304  * to generate a prologue to the store instruction that loads the surrounding
305  * bits, clears the destination field, and ORs in the new value of the field.
306  * In the diagram below the "st?" is the store instruction that is generated to
307  * store the containing word that is generating after calling this function.
308  *
309  * ld	[dst->dn_reg], r1
310  * setx	~(((1 << cte_bits) - 1) << (ctm_offset % NBBY)), r2
311  * and	r1, r2, r1
312  *
313  * setx	(1 << cte_bits) - 1, r2
314  * and	src->dn_reg, r2, r2
315  * setx ctm_offset % NBBY, r3
316  * sll	r2, r3, r2
317  *
318  * or	r1, r2, r1
319  * st?	r1, [dst->dn_reg]
320  *
321  * This routine allocates a new register to hold the value to be stored and
322  * returns it.  The caller is responsible for freeing this register later.
323  */
324 static int
325 dt_cg_field_set(dt_node_t *src, dt_irlist_t *dlp,
326     dt_regset_t *drp, dt_node_t *dst)
327 {
328 	uint64_t cmask, fmask, shift;
329 	dif_instr_t instr;
330 	int r1, r2, r3;
331 
332 	ctf_membinfo_t m;
333 	ctf_encoding_t e;
334 	ctf_file_t *fp, *ofp;
335 	ctf_id_t type;
336 
337 	assert(dst->dn_op == DT_TOK_PTR || dst->dn_op == DT_TOK_DOT);
338 	assert(dst->dn_right->dn_kind == DT_NODE_IDENT);
339 
340 	fp = dst->dn_left->dn_ctfp;
341 	type = ctf_type_resolve(fp, dst->dn_left->dn_type);
342 
343 	if (dst->dn_op == DT_TOK_PTR) {
344 		type = ctf_type_reference(fp, type);
345 		type = ctf_type_resolve(fp, type);
346 	}
347 
348 	if ((fp = dt_cg_membinfo(ofp = fp, type,
349 	    dst->dn_right->dn_string, &m)) == NULL) {
350 		yypcb->pcb_hdl->dt_ctferr = ctf_errno(ofp);
351 		longjmp(yypcb->pcb_jmpbuf, EDT_CTF);
352 	}
353 
354 	if (ctf_type_encoding(fp, m.ctm_type, &e) != 0 || e.cte_bits > 64) {
355 		xyerror(D_UNKNOWN, "cg: bad field: off %lu type <%ld> "
356 		    "bits %u\n", m.ctm_offset, m.ctm_type, e.cte_bits);
357 	}
358 
359 	r1 = dt_regset_alloc(drp);
360 	r2 = dt_regset_alloc(drp);
361 	r3 = dt_regset_alloc(drp);
362 
363 	/*
364 	 * Compute shifts and masks.  We need to compute "shift" as the amount
365 	 * we need to shift left to position our field in the containing word.
366 	 * Refer to the comments in dt_cg_field_get(), above, for more info.
367 	 * We then compute fmask as the mask that truncates the value in the
368 	 * input register to width cte_bits, and cmask as the mask used to
369 	 * pass through the containing bits and zero the field bits.
370 	 */
371 #ifdef _BIG_ENDIAN
372 	shift = clp2(P2ROUNDUP(e.cte_bits, NBBY) / NBBY) * NBBY -
373 	    (m.ctm_offset % NBBY + e.cte_bits);
374 #else
375 	shift = m.ctm_offset % NBBY;
376 #endif
377 	fmask = (1ULL << e.cte_bits) - 1;
378 	cmask = ~(fmask << shift);
379 
380 	instr = DIF_INSTR_LOAD(
381 	    dt_cg_load(dst, fp, m.ctm_type), dst->dn_reg, r1);
382 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
383 
384 	dt_cg_setx(dlp, r2, cmask);
385 	instr = DIF_INSTR_FMT(DIF_OP_AND, r1, r2, r1);
386 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
387 
388 	dt_cg_setx(dlp, r2, fmask);
389 	instr = DIF_INSTR_FMT(DIF_OP_AND, src->dn_reg, r2, r2);
390 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
391 
392 	dt_cg_setx(dlp, r3, shift);
393 	instr = DIF_INSTR_FMT(DIF_OP_SLL, r2, r3, r2);
394 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
395 
396 	instr = DIF_INSTR_FMT(DIF_OP_OR, r1, r2, r1);
397 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
398 
399 	dt_regset_free(drp, r3);
400 	dt_regset_free(drp, r2);
401 
402 	return (r1);
403 }
404 
405 static void
406 dt_cg_store(dt_node_t *src, dt_irlist_t *dlp, dt_regset_t *drp, dt_node_t *dst)
407 {
408 	ctf_encoding_t e;
409 	dif_instr_t instr;
410 	size_t size;
411 	int reg;
412 
413 	/*
414 	 * If we're loading a bit-field, the size of our store is found by
415 	 * rounding dst's cte_bits up to a byte boundary and then finding the
416 	 * nearest power of two to this value (see clp2(), above).
417 	 */
418 	if ((dst->dn_flags & DT_NF_BITFIELD) &&
419 	    ctf_type_encoding(dst->dn_ctfp, dst->dn_type, &e) != CTF_ERR)
420 		size = clp2(P2ROUNDUP(e.cte_bits, NBBY) / NBBY);
421 	else
422 		size = dt_node_type_size(src);
423 
424 	if (src->dn_flags & DT_NF_REF) {
425 		reg = dt_regset_alloc(drp);
426 		dt_cg_setx(dlp, reg, size);
427 		instr = DIF_INSTR_COPYS(src->dn_reg, reg, dst->dn_reg);
428 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
429 		dt_regset_free(drp, reg);
430 	} else {
431 		if (dst->dn_flags & DT_NF_BITFIELD)
432 			reg = dt_cg_field_set(src, dlp, drp, dst);
433 		else
434 			reg = src->dn_reg;
435 
436 		switch (size) {
437 		case 1:
438 			instr = DIF_INSTR_STORE(DIF_OP_STB, reg, dst->dn_reg);
439 			break;
440 		case 2:
441 			instr = DIF_INSTR_STORE(DIF_OP_STH, reg, dst->dn_reg);
442 			break;
443 		case 4:
444 			instr = DIF_INSTR_STORE(DIF_OP_STW, reg, dst->dn_reg);
445 			break;
446 		case 8:
447 			instr = DIF_INSTR_STORE(DIF_OP_STX, reg, dst->dn_reg);
448 			break;
449 		default:
450 			xyerror(D_UNKNOWN, "internal error -- cg cannot store "
451 			    "size %lu when passed by value\n", (ulong_t)size);
452 		}
453 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
454 
455 		if (dst->dn_flags & DT_NF_BITFIELD)
456 			dt_regset_free(drp, reg);
457 	}
458 }
459 
460 /*
461  * Generate code for a typecast or for argument promotion from the type of the
462  * actual to the type of the formal.  We need to generate code for casts when
463  * a scalar type is being narrowed or changing signed-ness.  We first shift the
464  * desired bits high (losing excess bits if narrowing) and then shift them down
465  * using logical shift (unsigned result) or arithmetic shift (signed result).
466  */
467 static void
468 dt_cg_typecast(const dt_node_t *src, const dt_node_t *dst,
469     dt_irlist_t *dlp, dt_regset_t *drp)
470 {
471 	size_t srcsize = dt_node_type_size(src);
472 	size_t dstsize = dt_node_type_size(dst);
473 
474 	dif_instr_t instr;
475 	int rg;
476 
477 	if (!dt_node_is_scalar(dst))
478 		return; /* not a scalar */
479 	if (dstsize == srcsize &&
480 	    ((src->dn_flags ^ dst->dn_flags) & DT_NF_SIGNED) == 0)
481 		return; /* not narrowing or changing signed-ness */
482 	if (dstsize > srcsize && (src->dn_flags & DT_NF_SIGNED) == 0)
483 		return; /* nothing to do in this case */
484 
485 	rg = dt_regset_alloc(drp);
486 
487 	if (dstsize > srcsize) {
488 		int n = sizeof (uint64_t) * NBBY - srcsize * NBBY;
489 		int s = (dstsize - srcsize) * NBBY;
490 
491 		dt_cg_setx(dlp, rg, n);
492 
493 		instr = DIF_INSTR_FMT(DIF_OP_SLL, src->dn_reg, rg, dst->dn_reg);
494 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
495 
496 		if ((dst->dn_flags & DT_NF_SIGNED) || n == s) {
497 			instr = DIF_INSTR_FMT(DIF_OP_SRA,
498 			    dst->dn_reg, rg, dst->dn_reg);
499 			dt_irlist_append(dlp,
500 			    dt_cg_node_alloc(DT_LBL_NONE, instr));
501 		} else {
502 			dt_cg_setx(dlp, rg, s);
503 			instr = DIF_INSTR_FMT(DIF_OP_SRA,
504 			    dst->dn_reg, rg, dst->dn_reg);
505 			dt_irlist_append(dlp,
506 			    dt_cg_node_alloc(DT_LBL_NONE, instr));
507 			dt_cg_setx(dlp, rg, n - s);
508 			instr = DIF_INSTR_FMT(DIF_OP_SRL,
509 			    dst->dn_reg, rg, dst->dn_reg);
510 			dt_irlist_append(dlp,
511 			    dt_cg_node_alloc(DT_LBL_NONE, instr));
512 		}
513 	} else if (dstsize != sizeof (uint64_t)) {
514 		int n = sizeof (uint64_t) * NBBY - dstsize * NBBY;
515 
516 		dt_cg_setx(dlp, rg, n);
517 
518 		instr = DIF_INSTR_FMT(DIF_OP_SLL, src->dn_reg, rg, dst->dn_reg);
519 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
520 
521 		instr = DIF_INSTR_FMT((dst->dn_flags & DT_NF_SIGNED) ?
522 		    DIF_OP_SRA : DIF_OP_SRL, dst->dn_reg, rg, dst->dn_reg);
523 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
524 	}
525 
526 	dt_regset_free(drp, rg);
527 }
528 
529 /*
530  * Generate code to push the specified argument list on to the tuple stack.
531  * We use this routine for handling subroutine calls and associative arrays.
532  * We must first generate code for all subexpressions before loading the stack
533  * because any subexpression could itself require the use of the tuple stack.
534  * This holds a number of registers equal to the number of arguments, but this
535  * is not a huge problem because the number of arguments can't exceed the
536  * number of tuple register stack elements anyway.  At most one extra register
537  * is required (either by dt_cg_typecast() or for dtdt_size, below).  This
538  * implies that a DIF implementation should offer a number of general purpose
539  * registers at least one greater than the number of tuple registers.
540  */
541 static void
542 dt_cg_arglist(dt_ident_t *idp, dt_node_t *args,
543     dt_irlist_t *dlp, dt_regset_t *drp)
544 {
545 	const dt_idsig_t *isp = idp->di_data;
546 	dt_node_t *dnp;
547 	int i = 0;
548 
549 	for (dnp = args; dnp != NULL; dnp = dnp->dn_list)
550 		dt_cg_node(dnp, dlp, drp);
551 
552 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, DIF_INSTR_FLUSHTS));
553 
554 	for (dnp = args; dnp != NULL; dnp = dnp->dn_list, i++) {
555 		dtrace_diftype_t t;
556 		dif_instr_t instr;
557 		uint_t op;
558 		int reg;
559 
560 		dt_node_diftype(yypcb->pcb_hdl, dnp, &t);
561 
562 		isp->dis_args[i].dn_reg = dnp->dn_reg; /* re-use register */
563 		dt_cg_typecast(dnp, &isp->dis_args[i], dlp, drp);
564 		isp->dis_args[i].dn_reg = -1;
565 
566 		if (t.dtdt_flags & DIF_TF_BYREF) {
567 			op = DIF_OP_PUSHTR;
568 			if (t.dtdt_size != 0) {
569 				reg = dt_regset_alloc(drp);
570 				dt_cg_setx(dlp, reg, t.dtdt_size);
571 			} else {
572 				reg = DIF_REG_R0;
573 			}
574 		} else {
575 			op = DIF_OP_PUSHTV;
576 			reg = DIF_REG_R0;
577 		}
578 
579 		instr = DIF_INSTR_PUSHTS(op, t.dtdt_kind, reg, dnp->dn_reg);
580 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
581 		dt_regset_free(drp, dnp->dn_reg);
582 
583 		if (reg != DIF_REG_R0)
584 			dt_regset_free(drp, reg);
585 	}
586 
587 	if (i > yypcb->pcb_hdl->dt_conf.dtc_diftupregs)
588 		longjmp(yypcb->pcb_jmpbuf, EDT_NOTUPREG);
589 }
590 
591 static void
592 dt_cg_arithmetic_op(dt_node_t *dnp, dt_irlist_t *dlp,
593     dt_regset_t *drp, uint_t op)
594 {
595 	int is_ptr_op = (dnp->dn_op == DT_TOK_ADD || dnp->dn_op == DT_TOK_SUB ||
596 	    dnp->dn_op == DT_TOK_ADD_EQ || dnp->dn_op == DT_TOK_SUB_EQ);
597 
598 	int lp_is_ptr = dt_node_is_pointer(dnp->dn_left);
599 	int rp_is_ptr = dt_node_is_pointer(dnp->dn_right);
600 
601 	dif_instr_t instr;
602 
603 	if (lp_is_ptr && rp_is_ptr) {
604 		assert(dnp->dn_op == DT_TOK_SUB);
605 		is_ptr_op = 0;
606 	}
607 
608 	dt_cg_node(dnp->dn_left, dlp, drp);
609 	if (is_ptr_op && rp_is_ptr)
610 		dt_cg_ptrsize(dnp, dlp, drp, DIF_OP_MUL, dnp->dn_left->dn_reg);
611 
612 	dt_cg_node(dnp->dn_right, dlp, drp);
613 	if (is_ptr_op && lp_is_ptr)
614 		dt_cg_ptrsize(dnp, dlp, drp, DIF_OP_MUL, dnp->dn_right->dn_reg);
615 
616 	instr = DIF_INSTR_FMT(op, dnp->dn_left->dn_reg,
617 	    dnp->dn_right->dn_reg, dnp->dn_left->dn_reg);
618 
619 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
620 	dt_regset_free(drp, dnp->dn_right->dn_reg);
621 	dnp->dn_reg = dnp->dn_left->dn_reg;
622 
623 	if (lp_is_ptr && rp_is_ptr)
624 		dt_cg_ptrsize(dnp->dn_right,
625 		    dlp, drp, DIF_OP_UDIV, dnp->dn_reg);
626 }
627 
628 static uint_t
629 dt_cg_stvar(const dt_ident_t *idp)
630 {
631 	static const uint_t aops[] = { DIF_OP_STGAA, DIF_OP_STTAA, DIF_OP_NOP };
632 	static const uint_t sops[] = { DIF_OP_STGS, DIF_OP_STTS, DIF_OP_STLS };
633 
634 	uint_t i = (((idp->di_flags & DT_IDFLG_LOCAL) != 0) << 1) |
635 	    ((idp->di_flags & DT_IDFLG_TLS) != 0);
636 
637 	return (idp->di_kind == DT_IDENT_ARRAY ? aops[i] : sops[i]);
638 }
639 
640 static void
641 dt_cg_prearith_op(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp, uint_t op)
642 {
643 	ctf_file_t *ctfp = dnp->dn_ctfp;
644 	dif_instr_t instr;
645 	ctf_id_t type;
646 	ssize_t size = 1;
647 	int reg;
648 
649 	if (dt_node_is_pointer(dnp)) {
650 		type = ctf_type_resolve(ctfp, dnp->dn_type);
651 		assert(ctf_type_kind(ctfp, type) == CTF_K_POINTER);
652 		size = ctf_type_size(ctfp, ctf_type_reference(ctfp, type));
653 	}
654 
655 	dt_cg_node(dnp->dn_child, dlp, drp);
656 	dnp->dn_reg = dnp->dn_child->dn_reg;
657 
658 	reg = dt_regset_alloc(drp);
659 	dt_cg_setx(dlp, reg, size);
660 
661 	instr = DIF_INSTR_FMT(op, dnp->dn_reg, reg, dnp->dn_reg);
662 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
663 	dt_regset_free(drp, reg);
664 
665 	/*
666 	 * If we are modifying a variable, generate an stv instruction from
667 	 * the variable specified by the identifier.  If we are storing to a
668 	 * memory address, generate code again for the left-hand side using
669 	 * DT_NF_REF to get the address, and then generate a store to it.
670 	 * In both paths, we store the value in dnp->dn_reg (the new value).
671 	 */
672 	if (dnp->dn_child->dn_kind == DT_NODE_VAR) {
673 		dt_ident_t *idp = dt_ident_resolve(dnp->dn_child->dn_ident);
674 
675 		idp->di_flags |= DT_IDFLG_DIFW;
676 		instr = DIF_INSTR_STV(dt_cg_stvar(idp),
677 		    idp->di_id, dnp->dn_reg);
678 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
679 	} else {
680 		uint_t rbit = dnp->dn_child->dn_flags & DT_NF_REF;
681 
682 		assert(dnp->dn_child->dn_flags & DT_NF_WRITABLE);
683 		assert(dnp->dn_child->dn_flags & DT_NF_LVALUE);
684 
685 		dnp->dn_child->dn_flags |= DT_NF_REF; /* force pass-by-ref */
686 		dt_cg_node(dnp->dn_child, dlp, drp);
687 
688 		dt_cg_store(dnp, dlp, drp, dnp->dn_child);
689 		dt_regset_free(drp, dnp->dn_child->dn_reg);
690 
691 		dnp->dn_left->dn_flags &= ~DT_NF_REF;
692 		dnp->dn_left->dn_flags |= rbit;
693 	}
694 }
695 
696 static void
697 dt_cg_postarith_op(dt_node_t *dnp, dt_irlist_t *dlp,
698     dt_regset_t *drp, uint_t op)
699 {
700 	ctf_file_t *ctfp = dnp->dn_ctfp;
701 	dif_instr_t instr;
702 	ctf_id_t type;
703 	ssize_t size = 1;
704 	int nreg;
705 
706 	if (dt_node_is_pointer(dnp)) {
707 		type = ctf_type_resolve(ctfp, dnp->dn_type);
708 		assert(ctf_type_kind(ctfp, type) == CTF_K_POINTER);
709 		size = ctf_type_size(ctfp, ctf_type_reference(ctfp, type));
710 	}
711 
712 	dt_cg_node(dnp->dn_child, dlp, drp);
713 	dnp->dn_reg = dnp->dn_child->dn_reg;
714 
715 	nreg = dt_regset_alloc(drp);
716 	dt_cg_setx(dlp, nreg, size);
717 	instr = DIF_INSTR_FMT(op, dnp->dn_reg, nreg, nreg);
718 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
719 
720 	/*
721 	 * If we are modifying a variable, generate an stv instruction from
722 	 * the variable specified by the identifier.  If we are storing to a
723 	 * memory address, generate code again for the left-hand side using
724 	 * DT_NF_REF to get the address, and then generate a store to it.
725 	 * In both paths, we store the value from 'nreg' (the new value).
726 	 */
727 	if (dnp->dn_child->dn_kind == DT_NODE_VAR) {
728 		dt_ident_t *idp = dt_ident_resolve(dnp->dn_child->dn_ident);
729 
730 		idp->di_flags |= DT_IDFLG_DIFW;
731 		instr = DIF_INSTR_STV(dt_cg_stvar(idp), idp->di_id, nreg);
732 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
733 	} else {
734 		uint_t rbit = dnp->dn_child->dn_flags & DT_NF_REF;
735 		int oreg = dnp->dn_reg;
736 
737 		assert(dnp->dn_child->dn_flags & DT_NF_WRITABLE);
738 		assert(dnp->dn_child->dn_flags & DT_NF_LVALUE);
739 
740 		dnp->dn_child->dn_flags |= DT_NF_REF; /* force pass-by-ref */
741 		dt_cg_node(dnp->dn_child, dlp, drp);
742 
743 		dnp->dn_reg = nreg;
744 		dt_cg_store(dnp, dlp, drp, dnp->dn_child);
745 		dnp->dn_reg = oreg;
746 
747 		dt_regset_free(drp, dnp->dn_child->dn_reg);
748 		dnp->dn_left->dn_flags &= ~DT_NF_REF;
749 		dnp->dn_left->dn_flags |= rbit;
750 	}
751 
752 	dt_regset_free(drp, nreg);
753 }
754 
755 /*
756  * Determine if we should perform signed or unsigned comparison for an OP2.
757  * If both operands are of arithmetic type, perform the usual arithmetic
758  * conversions to determine the common real type for comparison [ISOC 6.5.8.3].
759  */
760 static int
761 dt_cg_compare_signed(dt_node_t *dnp)
762 {
763 	dt_node_t dn;
764 
765 	if (dt_node_is_string(dnp->dn_left) ||
766 	    dt_node_is_string(dnp->dn_right))
767 		return (1); /* strings always compare signed */
768 	else if (!dt_node_is_arith(dnp->dn_left) ||
769 	    !dt_node_is_arith(dnp->dn_right))
770 		return (0); /* non-arithmetic types always compare unsigned */
771 
772 	bzero(&dn, sizeof (dn));
773 	dt_node_promote(dnp->dn_left, dnp->dn_right, &dn);
774 	return (dn.dn_flags & DT_NF_SIGNED);
775 }
776 
777 static void
778 dt_cg_compare_op(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp, uint_t op)
779 {
780 	uint_t lbl_true = dt_irlist_label(dlp);
781 	uint_t lbl_post = dt_irlist_label(dlp);
782 
783 	dif_instr_t instr;
784 	uint_t opc;
785 
786 	dt_cg_node(dnp->dn_left, dlp, drp);
787 	dt_cg_node(dnp->dn_right, dlp, drp);
788 
789 	if (dt_node_is_string(dnp->dn_left) || dt_node_is_string(dnp->dn_right))
790 		opc = DIF_OP_SCMP;
791 	else
792 		opc = DIF_OP_CMP;
793 
794 	instr = DIF_INSTR_CMP(opc, dnp->dn_left->dn_reg, dnp->dn_right->dn_reg);
795 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
796 	dt_regset_free(drp, dnp->dn_right->dn_reg);
797 	dnp->dn_reg = dnp->dn_left->dn_reg;
798 
799 	instr = DIF_INSTR_BRANCH(op, lbl_true);
800 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
801 
802 	instr = DIF_INSTR_MOV(DIF_REG_R0, dnp->dn_reg);
803 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
804 
805 	instr = DIF_INSTR_BRANCH(DIF_OP_BA, lbl_post);
806 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
807 
808 	dt_cg_xsetx(dlp, NULL, lbl_true, dnp->dn_reg, 1);
809 	dt_irlist_append(dlp, dt_cg_node_alloc(lbl_post, DIF_INSTR_NOP));
810 }
811 
812 /*
813  * Code generation for the ternary op requires some trickery with the assembler
814  * in order to conserve registers.  We generate code for dn_expr and dn_left
815  * and free their registers so they do not have be consumed across codegen for
816  * dn_right.  We insert a dummy MOV at the end of dn_left into the destination
817  * register, which is not yet known because we haven't done dn_right yet, and
818  * save the pointer to this instruction node.  We then generate code for
819  * dn_right and use its register as our output.  Finally, we reach back and
820  * patch the instruction for dn_left to move its output into this register.
821  */
822 static void
823 dt_cg_ternary_op(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
824 {
825 	uint_t lbl_false = dt_irlist_label(dlp);
826 	uint_t lbl_post = dt_irlist_label(dlp);
827 
828 	dif_instr_t instr;
829 	dt_irnode_t *dip;
830 
831 	dt_cg_node(dnp->dn_expr, dlp, drp);
832 	instr = DIF_INSTR_TST(dnp->dn_expr->dn_reg);
833 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
834 	dt_regset_free(drp, dnp->dn_expr->dn_reg);
835 
836 	instr = DIF_INSTR_BRANCH(DIF_OP_BE, lbl_false);
837 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
838 
839 	dt_cg_node(dnp->dn_left, dlp, drp);
840 	instr = DIF_INSTR_MOV(dnp->dn_left->dn_reg, DIF_REG_R0);
841 	dip = dt_cg_node_alloc(DT_LBL_NONE, instr); /* save dip for below */
842 	dt_irlist_append(dlp, dip);
843 	dt_regset_free(drp, dnp->dn_left->dn_reg);
844 
845 	instr = DIF_INSTR_BRANCH(DIF_OP_BA, lbl_post);
846 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
847 
848 	dt_irlist_append(dlp, dt_cg_node_alloc(lbl_false, DIF_INSTR_NOP));
849 	dt_cg_node(dnp->dn_right, dlp, drp);
850 	dnp->dn_reg = dnp->dn_right->dn_reg;
851 
852 	/*
853 	 * Now that dn_reg is assigned, reach back and patch the correct MOV
854 	 * instruction into the tail of dn_left.  We know dn_reg was unused
855 	 * at that point because otherwise dn_right couldn't have allocated it.
856 	 */
857 	dip->di_instr = DIF_INSTR_MOV(dnp->dn_left->dn_reg, dnp->dn_reg);
858 	dt_irlist_append(dlp, dt_cg_node_alloc(lbl_post, DIF_INSTR_NOP));
859 }
860 
861 static void
862 dt_cg_logical_and(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
863 {
864 	uint_t lbl_false = dt_irlist_label(dlp);
865 	uint_t lbl_post = dt_irlist_label(dlp);
866 
867 	dif_instr_t instr;
868 
869 	dt_cg_node(dnp->dn_left, dlp, drp);
870 	instr = DIF_INSTR_TST(dnp->dn_left->dn_reg);
871 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
872 	dt_regset_free(drp, dnp->dn_left->dn_reg);
873 
874 	instr = DIF_INSTR_BRANCH(DIF_OP_BE, lbl_false);
875 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
876 
877 	dt_cg_node(dnp->dn_right, dlp, drp);
878 	instr = DIF_INSTR_TST(dnp->dn_right->dn_reg);
879 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
880 	dnp->dn_reg = dnp->dn_right->dn_reg;
881 
882 	instr = DIF_INSTR_BRANCH(DIF_OP_BE, lbl_false);
883 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
884 
885 	dt_cg_setx(dlp, dnp->dn_reg, 1);
886 
887 	instr = DIF_INSTR_BRANCH(DIF_OP_BA, lbl_post);
888 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
889 
890 	instr = DIF_INSTR_MOV(DIF_REG_R0, dnp->dn_reg);
891 	dt_irlist_append(dlp, dt_cg_node_alloc(lbl_false, instr));
892 
893 	dt_irlist_append(dlp, dt_cg_node_alloc(lbl_post, DIF_INSTR_NOP));
894 }
895 
896 static void
897 dt_cg_logical_xor(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
898 {
899 	uint_t lbl_next = dt_irlist_label(dlp);
900 	uint_t lbl_tail = dt_irlist_label(dlp);
901 
902 	dif_instr_t instr;
903 
904 	dt_cg_node(dnp->dn_left, dlp, drp);
905 	instr = DIF_INSTR_TST(dnp->dn_left->dn_reg);
906 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
907 
908 	instr = DIF_INSTR_BRANCH(DIF_OP_BE, lbl_next);
909 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
910 	dt_cg_setx(dlp, dnp->dn_left->dn_reg, 1);
911 
912 	dt_irlist_append(dlp, dt_cg_node_alloc(lbl_next, DIF_INSTR_NOP));
913 	dt_cg_node(dnp->dn_right, dlp, drp);
914 
915 	instr = DIF_INSTR_TST(dnp->dn_right->dn_reg);
916 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
917 
918 	instr = DIF_INSTR_BRANCH(DIF_OP_BE, lbl_tail);
919 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
920 	dt_cg_setx(dlp, dnp->dn_right->dn_reg, 1);
921 
922 	instr = DIF_INSTR_FMT(DIF_OP_XOR, dnp->dn_left->dn_reg,
923 	    dnp->dn_right->dn_reg, dnp->dn_left->dn_reg);
924 
925 	dt_irlist_append(dlp, dt_cg_node_alloc(lbl_tail, instr));
926 
927 	dt_regset_free(drp, dnp->dn_right->dn_reg);
928 	dnp->dn_reg = dnp->dn_left->dn_reg;
929 }
930 
931 static void
932 dt_cg_logical_or(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
933 {
934 	uint_t lbl_true = dt_irlist_label(dlp);
935 	uint_t lbl_false = dt_irlist_label(dlp);
936 	uint_t lbl_post = dt_irlist_label(dlp);
937 
938 	dif_instr_t instr;
939 
940 	dt_cg_node(dnp->dn_left, dlp, drp);
941 	instr = DIF_INSTR_TST(dnp->dn_left->dn_reg);
942 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
943 	dt_regset_free(drp, dnp->dn_left->dn_reg);
944 
945 	instr = DIF_INSTR_BRANCH(DIF_OP_BNE, lbl_true);
946 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
947 
948 	dt_cg_node(dnp->dn_right, dlp, drp);
949 	instr = DIF_INSTR_TST(dnp->dn_right->dn_reg);
950 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
951 	dnp->dn_reg = dnp->dn_right->dn_reg;
952 
953 	instr = DIF_INSTR_BRANCH(DIF_OP_BE, lbl_false);
954 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
955 
956 	dt_cg_xsetx(dlp, NULL, lbl_true, dnp->dn_reg, 1);
957 
958 	instr = DIF_INSTR_BRANCH(DIF_OP_BA, lbl_post);
959 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
960 
961 	instr = DIF_INSTR_MOV(DIF_REG_R0, dnp->dn_reg);
962 	dt_irlist_append(dlp, dt_cg_node_alloc(lbl_false, instr));
963 
964 	dt_irlist_append(dlp, dt_cg_node_alloc(lbl_post, DIF_INSTR_NOP));
965 }
966 
967 static void
968 dt_cg_logical_neg(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
969 {
970 	uint_t lbl_zero = dt_irlist_label(dlp);
971 	uint_t lbl_post = dt_irlist_label(dlp);
972 
973 	dif_instr_t instr;
974 
975 	dt_cg_node(dnp->dn_child, dlp, drp);
976 	dnp->dn_reg = dnp->dn_child->dn_reg;
977 
978 	instr = DIF_INSTR_TST(dnp->dn_reg);
979 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
980 
981 	instr = DIF_INSTR_BRANCH(DIF_OP_BE, lbl_zero);
982 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
983 
984 	instr = DIF_INSTR_MOV(DIF_REG_R0, dnp->dn_reg);
985 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
986 
987 	instr = DIF_INSTR_BRANCH(DIF_OP_BA, lbl_post);
988 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
989 
990 	dt_cg_xsetx(dlp, NULL, lbl_zero, dnp->dn_reg, 1);
991 	dt_irlist_append(dlp, dt_cg_node_alloc(lbl_post, DIF_INSTR_NOP));
992 }
993 
994 static void
995 dt_cg_asgn_op(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
996 {
997 	dif_instr_t instr;
998 	dt_ident_t *idp;
999 
1000 	/*
1001 	 * If we are performing a structure assignment of a translated type,
1002 	 * we must instantiate all members and create a snapshot of the object
1003 	 * in scratch space.  We allocs a chunk of memory, generate code for
1004 	 * each member, and then set dnp->dn_reg to the scratch object address.
1005 	 */
1006 	if ((idp = dt_node_resolve(dnp->dn_right, DT_IDENT_XLSOU)) != NULL) {
1007 		ctf_membinfo_t ctm;
1008 		dt_xlator_t *dxp = idp->di_data;
1009 		dt_node_t *mnp, dn, mn;
1010 		int r1, r2;
1011 
1012 		/*
1013 		 * Create two fake dt_node_t's representing operator "." and a
1014 		 * right-hand identifier child node.  These will be repeatedly
1015 		 * modified according to each instantiated member so that we
1016 		 * can pass them to dt_cg_store() and effect a member store.
1017 		 */
1018 		bzero(&dn, sizeof (dt_node_t));
1019 		dn.dn_kind = DT_NODE_OP2;
1020 		dn.dn_op = DT_TOK_DOT;
1021 		dn.dn_left = dnp;
1022 		dn.dn_right = &mn;
1023 
1024 		bzero(&mn, sizeof (dt_node_t));
1025 		mn.dn_kind = DT_NODE_IDENT;
1026 		mn.dn_op = DT_TOK_IDENT;
1027 
1028 		/*
1029 		 * Allocate a register for our scratch data pointer.  First we
1030 		 * set it to the size of our data structure, and then replace
1031 		 * it with the result of an allocs of the specified size.
1032 		 */
1033 		r1 = dt_regset_alloc(drp);
1034 		dt_cg_setx(dlp, r1,
1035 		    ctf_type_size(dxp->dx_dst_ctfp, dxp->dx_dst_base));
1036 
1037 		instr = DIF_INSTR_ALLOCS(r1, r1);
1038 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1039 
1040 		/*
1041 		 * When dt_cg_asgn_op() is called, we have already generated
1042 		 * code for dnp->dn_right, which is the translator input.  We
1043 		 * now associate this register with the translator's input
1044 		 * identifier so it can be referenced during our member loop.
1045 		 */
1046 		dxp->dx_ident->di_flags |= DT_IDFLG_CGREG;
1047 		dxp->dx_ident->di_id = dnp->dn_right->dn_reg;
1048 
1049 		for (mnp = dxp->dx_members; mnp != NULL; mnp = mnp->dn_list) {
1050 			/*
1051 			 * Generate code for the translator member expression,
1052 			 * and then cast the result to the member type.
1053 			 */
1054 			dt_cg_node(mnp->dn_membexpr, dlp, drp);
1055 			mnp->dn_reg = mnp->dn_membexpr->dn_reg;
1056 			dt_cg_typecast(mnp->dn_membexpr, mnp, dlp, drp);
1057 
1058 			/*
1059 			 * Ask CTF for the offset of the member so we can store
1060 			 * to the appropriate offset.  This call has already
1061 			 * been done once by the parser, so it should succeed.
1062 			 */
1063 			if (ctf_member_info(dxp->dx_dst_ctfp, dxp->dx_dst_base,
1064 			    mnp->dn_membname, &ctm) == CTF_ERR) {
1065 				yypcb->pcb_hdl->dt_ctferr =
1066 				    ctf_errno(dxp->dx_dst_ctfp);
1067 				longjmp(yypcb->pcb_jmpbuf, EDT_CTF);
1068 			}
1069 
1070 			/*
1071 			 * If the destination member is at offset 0, store the
1072 			 * result directly to r1 (the scratch buffer address).
1073 			 * Otherwise allocate another temporary for the offset
1074 			 * and add r1 to it before storing the result.
1075 			 */
1076 			if (ctm.ctm_offset != 0) {
1077 				r2 = dt_regset_alloc(drp);
1078 
1079 				/*
1080 				 * Add the member offset rounded down to the
1081 				 * nearest byte.  If the offset was not aligned
1082 				 * on a byte boundary, this member is a bit-
1083 				 * field and dt_cg_store() will handle masking.
1084 				 */
1085 				dt_cg_setx(dlp, r2, ctm.ctm_offset / NBBY);
1086 				instr = DIF_INSTR_FMT(DIF_OP_ADD, r1, r2, r2);
1087 				dt_irlist_append(dlp,
1088 				    dt_cg_node_alloc(DT_LBL_NONE, instr));
1089 
1090 				dt_node_type_propagate(mnp, &dn);
1091 				dn.dn_right->dn_string = mnp->dn_membname;
1092 				dn.dn_reg = r2;
1093 
1094 				dt_cg_store(mnp, dlp, drp, &dn);
1095 				dt_regset_free(drp, r2);
1096 
1097 			} else {
1098 				dt_node_type_propagate(mnp, &dn);
1099 				dn.dn_right->dn_string = mnp->dn_membname;
1100 				dn.dn_reg = r1;
1101 
1102 				dt_cg_store(mnp, dlp, drp, &dn);
1103 			}
1104 
1105 			dt_regset_free(drp, mnp->dn_reg);
1106 		}
1107 
1108 		dxp->dx_ident->di_flags &= ~DT_IDFLG_CGREG;
1109 		dxp->dx_ident->di_id = 0;
1110 
1111 		if (dnp->dn_right->dn_reg != -1)
1112 			dt_regset_free(drp, dnp->dn_right->dn_reg);
1113 
1114 		assert(dnp->dn_reg == dnp->dn_right->dn_reg);
1115 		dnp->dn_reg = r1;
1116 	}
1117 
1118 	/*
1119 	 * If we are storing to a memory address, generate code again for the
1120 	 * left-hand side using DT_NF_REF to get the address, and then generate
1121 	 * a store to it.
1122 	 *
1123 	 * Both here and the other variable-store paths, we assume dnp->dn_reg
1124 	 * already has the new value.
1125 	 */
1126 	if (dnp->dn_left->dn_kind != DT_NODE_VAR) {
1127 		uint_t rbit = dnp->dn_left->dn_flags & DT_NF_REF;
1128 
1129 		assert(dnp->dn_left->dn_flags & DT_NF_WRITABLE);
1130 		assert(dnp->dn_left->dn_flags & DT_NF_LVALUE);
1131 
1132 		dnp->dn_left->dn_flags |= DT_NF_REF; /* force pass-by-ref */
1133 
1134 		dt_cg_node(dnp->dn_left, dlp, drp);
1135 		dt_cg_store(dnp, dlp, drp, dnp->dn_left);
1136 		dt_regset_free(drp, dnp->dn_left->dn_reg);
1137 
1138 		dnp->dn_left->dn_flags &= ~DT_NF_REF;
1139 		dnp->dn_left->dn_flags |= rbit;
1140 		return;
1141 	}
1142 
1143 	idp = dt_ident_resolve(dnp->dn_left->dn_ident);
1144 	idp->di_flags |= DT_IDFLG_DIFW;
1145 
1146 	/*
1147 	 * Storing to an array variable is a special case.
1148 	 * Only 'uregs[]' supports this for the time being.
1149 	 */
1150 	if (idp->di_kind == DT_IDENT_ARRAY &&
1151 	    idp->di_id <= DIF_VAR_ARRAY_MAX) {
1152 		dt_node_t *idx = dnp->dn_left->dn_args;
1153 
1154 		dt_cg_node(idx, dlp, drp);
1155 		instr = DIF_INSTR_FMT(DIF_OP_STGA, idp->di_id, idx->dn_reg,
1156 		    dnp->dn_reg);
1157 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1158 		dt_regset_free(drp, idx->dn_reg);
1159 		return;
1160 	}
1161 
1162 	if (idp->di_kind == DT_IDENT_ARRAY)
1163 		dt_cg_arglist(idp, dnp->dn_left->dn_args, dlp, drp);
1164 
1165 	instr = DIF_INSTR_STV(dt_cg_stvar(idp), idp->di_id, dnp->dn_reg);
1166 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1167 }
1168 
1169 static void
1170 dt_cg_assoc_op(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
1171 {
1172 	dif_instr_t instr;
1173 	uint_t op;
1174 
1175 	assert(dnp->dn_kind == DT_NODE_VAR);
1176 	assert(!(dnp->dn_ident->di_flags & DT_IDFLG_LOCAL));
1177 	assert(dnp->dn_args != NULL);
1178 
1179 	dt_cg_arglist(dnp->dn_ident, dnp->dn_args, dlp, drp);
1180 
1181 	dnp->dn_reg = dt_regset_alloc(drp);
1182 
1183 	if (dnp->dn_ident->di_flags & DT_IDFLG_TLS)
1184 		op = DIF_OP_LDTAA;
1185 	else
1186 		op = DIF_OP_LDGAA;
1187 
1188 	dnp->dn_ident->di_flags |= DT_IDFLG_DIFR;
1189 	instr = DIF_INSTR_LDV(op, dnp->dn_ident->di_id, dnp->dn_reg);
1190 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1191 
1192 	/*
1193 	 * If the associative array is a pass-by-reference type, then we are
1194 	 * loading its value as a pointer to either load or store through it.
1195 	 * The array element in question may not have been faulted in yet, in
1196 	 * which case DIF_OP_LD*AA will return zero.  We append an epilogue
1197 	 * of instructions similar to the following:
1198 	 *
1199 	 *	  ld?aa	 id, %r1	! base ld?aa instruction above
1200 	 *	  tst	 %r1		! start of epilogue
1201 	 *   +--- bne	 label
1202 	 *   |    setx	 size, %r1
1203 	 *   |    allocs %r1, %r1
1204 	 *   |    st?aa	 id, %r1
1205 	 *   |    ld?aa	 id, %r1
1206 	 *   v
1207 	 * label: < rest of code >
1208 	 *
1209 	 * The idea is that we allocs a zero-filled chunk of scratch space and
1210 	 * do a DIF_OP_ST*AA to fault in and initialize the array element, and
1211 	 * then reload it to get the faulted-in address of the new variable
1212 	 * storage.  This isn't cheap, but pass-by-ref associative array values
1213 	 * are (thus far) uncommon and the allocs cost only occurs once.  If
1214 	 * this path becomes important to DTrace users, we can improve things
1215 	 * by adding a new DIF opcode to fault in associative array elements.
1216 	 */
1217 	if (dnp->dn_flags & DT_NF_REF) {
1218 		uint_t stvop = op == DIF_OP_LDTAA ? DIF_OP_STTAA : DIF_OP_STGAA;
1219 		uint_t label = dt_irlist_label(dlp);
1220 
1221 		instr = DIF_INSTR_TST(dnp->dn_reg);
1222 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1223 
1224 		instr = DIF_INSTR_BRANCH(DIF_OP_BNE, label);
1225 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1226 
1227 		dt_cg_setx(dlp, dnp->dn_reg, dt_node_type_size(dnp));
1228 		instr = DIF_INSTR_ALLOCS(dnp->dn_reg, dnp->dn_reg);
1229 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1230 
1231 		dnp->dn_ident->di_flags |= DT_IDFLG_DIFW;
1232 		instr = DIF_INSTR_STV(stvop, dnp->dn_ident->di_id, dnp->dn_reg);
1233 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1234 
1235 		instr = DIF_INSTR_LDV(op, dnp->dn_ident->di_id, dnp->dn_reg);
1236 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1237 
1238 		dt_irlist_append(dlp, dt_cg_node_alloc(label, DIF_INSTR_NOP));
1239 	}
1240 }
1241 
1242 static void
1243 dt_cg_array_op(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
1244 {
1245 	dt_probe_t *prp = yypcb->pcb_probe;
1246 	uintmax_t saved = dnp->dn_args->dn_value;
1247 	dt_ident_t *idp = dnp->dn_ident;
1248 
1249 	dif_instr_t instr;
1250 	uint_t op;
1251 	size_t size;
1252 	int reg, n;
1253 
1254 	assert(dnp->dn_kind == DT_NODE_VAR);
1255 	assert(!(idp->di_flags & DT_IDFLG_LOCAL));
1256 
1257 	assert(dnp->dn_args->dn_kind == DT_NODE_INT);
1258 	assert(dnp->dn_args->dn_list == NULL);
1259 
1260 	/*
1261 	 * If this is a reference in the args[] array, temporarily modify the
1262 	 * array index according to the static argument mapping (if any),
1263 	 * unless the argument reference is provided by a dynamic translator.
1264 	 * If we're using a dynamic translator for args[], then just set dn_reg
1265 	 * to an invalid reg and return: DIF_OP_XLARG will fetch the arg later.
1266 	 */
1267 	if (idp->di_id == DIF_VAR_ARGS) {
1268 		if ((idp->di_kind == DT_IDENT_XLPTR ||
1269 		    idp->di_kind == DT_IDENT_XLSOU) &&
1270 		    dt_xlator_dynamic(idp->di_data)) {
1271 			dnp->dn_reg = -1;
1272 			return;
1273 		}
1274 		dnp->dn_args->dn_value = prp->pr_mapping[saved];
1275 	}
1276 
1277 	dt_cg_node(dnp->dn_args, dlp, drp);
1278 	dnp->dn_args->dn_value = saved;
1279 
1280 	dnp->dn_reg = dnp->dn_args->dn_reg;
1281 
1282 	if (idp->di_flags & DT_IDFLG_TLS)
1283 		op = DIF_OP_LDTA;
1284 	else
1285 		op = DIF_OP_LDGA;
1286 
1287 	idp->di_flags |= DT_IDFLG_DIFR;
1288 
1289 	instr = DIF_INSTR_LDA(op, idp->di_id,
1290 	    dnp->dn_args->dn_reg, dnp->dn_reg);
1291 
1292 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1293 
1294 	/*
1295 	 * If this is a reference to the args[] array, we need to take the
1296 	 * additional step of explicitly eliminating any bits larger than the
1297 	 * type size: the DIF interpreter in the kernel will always give us
1298 	 * the raw (64-bit) argument value, and any bits larger than the type
1299 	 * size may be junk.  As a practical matter, this arises only on 64-bit
1300 	 * architectures and only when the argument index is larger than the
1301 	 * number of arguments passed directly to DTrace: if a 8-, 16- or
1302 	 * 32-bit argument must be retrieved from the stack, it is possible
1303 	 * (and it some cases, likely) that the upper bits will be garbage.
1304 	 */
1305 	if (idp->di_id != DIF_VAR_ARGS || !dt_node_is_scalar(dnp))
1306 		return;
1307 
1308 	if ((size = dt_node_type_size(dnp)) == sizeof (uint64_t))
1309 		return;
1310 
1311 	reg = dt_regset_alloc(drp);
1312 	assert(size < sizeof (uint64_t));
1313 	n = sizeof (uint64_t) * NBBY - size * NBBY;
1314 
1315 	dt_cg_setx(dlp, reg, n);
1316 
1317 	instr = DIF_INSTR_FMT(DIF_OP_SLL, dnp->dn_reg, reg, dnp->dn_reg);
1318 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1319 
1320 	instr = DIF_INSTR_FMT((dnp->dn_flags & DT_NF_SIGNED) ?
1321 	    DIF_OP_SRA : DIF_OP_SRL, dnp->dn_reg, reg, dnp->dn_reg);
1322 
1323 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1324 	dt_regset_free(drp, reg);
1325 }
1326 
1327 /*
1328  * Generate code for an inlined variable reference.  Inlines can be used to
1329  * define either scalar or associative array substitutions.  For scalars, we
1330  * simply generate code for the parse tree saved in the identifier's din_root,
1331  * and then cast the resulting expression to the inline's declaration type.
1332  * For arrays, we take the input parameter subtrees from dnp->dn_args and
1333  * temporarily store them in the din_root of each din_argv[i] identifier,
1334  * which are themselves inlines and were set up for us by the parser.  The
1335  * result is that any reference to the inlined parameter inside the top-level
1336  * din_root will turn into a recursive call to dt_cg_inline() for a scalar
1337  * inline whose din_root will refer to the subtree pointed to by the argument.
1338  */
1339 static void
1340 dt_cg_inline(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
1341 {
1342 	dt_ident_t *idp = dnp->dn_ident;
1343 	dt_idnode_t *inp = idp->di_iarg;
1344 
1345 	dt_idnode_t *pinp;
1346 	dt_node_t *pnp;
1347 	int i;
1348 
1349 	assert(idp->di_flags & DT_IDFLG_INLINE);
1350 	assert(idp->di_ops == &dt_idops_inline);
1351 
1352 	if (idp->di_kind == DT_IDENT_ARRAY) {
1353 		for (i = 0, pnp = dnp->dn_args;
1354 		    pnp != NULL; pnp = pnp->dn_list, i++) {
1355 			if (inp->din_argv[i] != NULL) {
1356 				pinp = inp->din_argv[i]->di_iarg;
1357 				pinp->din_root = pnp;
1358 			}
1359 		}
1360 	}
1361 
1362 	dt_cg_node(inp->din_root, dlp, drp);
1363 	dnp->dn_reg = inp->din_root->dn_reg;
1364 	dt_cg_typecast(inp->din_root, dnp, dlp, drp);
1365 
1366 	if (idp->di_kind == DT_IDENT_ARRAY) {
1367 		for (i = 0; i < inp->din_argc; i++) {
1368 			pinp = inp->din_argv[i]->di_iarg;
1369 			pinp->din_root = NULL;
1370 		}
1371 	}
1372 }
1373 
1374 typedef struct dt_xlmemb {
1375 	dt_ident_t *dtxl_idp;		/* translated ident */
1376 	dt_irlist_t *dtxl_dlp;		/* instruction list */
1377 	dt_regset_t *dtxl_drp;		/* register set */
1378 	int dtxl_sreg;			/* location of the translation input */
1379 	int dtxl_dreg;			/* location of our allocated buffer */
1380 } dt_xlmemb_t;
1381 
1382 /*ARGSUSED*/
1383 static int
1384 dt_cg_xlate_member(const char *name, ctf_id_t type, ulong_t off, void *arg)
1385 {
1386 	dt_xlmemb_t *dx = arg;
1387 	dt_ident_t *idp = dx->dtxl_idp;
1388 	dt_irlist_t *dlp = dx->dtxl_dlp;
1389 	dt_regset_t *drp = dx->dtxl_drp;
1390 
1391 	dt_node_t *mnp;
1392 	dt_xlator_t *dxp;
1393 
1394 	int reg, treg;
1395 	uint32_t instr;
1396 	size_t size;
1397 
1398 	/* Generate code for the translation. */
1399 	dxp = idp->di_data;
1400 	mnp = dt_xlator_member(dxp, name);
1401 
1402 	/* If there's no translator for the given member, skip it. */
1403 	if (mnp == NULL)
1404 		return (0);
1405 
1406 	dxp->dx_ident->di_flags |= DT_IDFLG_CGREG;
1407 	dxp->dx_ident->di_id = dx->dtxl_sreg;
1408 
1409 	dt_cg_node(mnp->dn_membexpr, dlp, drp);
1410 
1411 	dxp->dx_ident->di_flags &= ~DT_IDFLG_CGREG;
1412 	dxp->dx_ident->di_id = 0;
1413 
1414 	treg = mnp->dn_membexpr->dn_reg;
1415 
1416 	/* Compute the offset into our buffer and store the result there. */
1417 	reg = dt_regset_alloc(drp);
1418 
1419 	dt_cg_setx(dlp, reg, off / NBBY);
1420 	instr = DIF_INSTR_FMT(DIF_OP_ADD, dx->dtxl_dreg, reg, reg);
1421 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1422 
1423 	size = ctf_type_size(mnp->dn_membexpr->dn_ctfp,
1424 	    mnp->dn_membexpr->dn_type);
1425 	if (dt_node_is_scalar(mnp->dn_membexpr)) {
1426 		/*
1427 		 * Copying scalars is simple.
1428 		 */
1429 		switch (size) {
1430 		case 1:
1431 			instr = DIF_INSTR_STORE(DIF_OP_STB, treg, reg);
1432 			break;
1433 		case 2:
1434 			instr = DIF_INSTR_STORE(DIF_OP_STH, treg, reg);
1435 			break;
1436 		case 4:
1437 			instr = DIF_INSTR_STORE(DIF_OP_STW, treg, reg);
1438 			break;
1439 		case 8:
1440 			instr = DIF_INSTR_STORE(DIF_OP_STX, treg, reg);
1441 			break;
1442 		default:
1443 			xyerror(D_UNKNOWN, "internal error -- unexpected "
1444 			    "size: %lu\n", (ulong_t)size);
1445 		}
1446 
1447 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1448 
1449 	} else if (dt_node_is_string(mnp->dn_membexpr)) {
1450 		int szreg;
1451 
1452 		/*
1453 		 * Use the copys instruction for strings.
1454 		 */
1455 		szreg = dt_regset_alloc(drp);
1456 		dt_cg_setx(dlp, szreg, size);
1457 		instr = DIF_INSTR_COPYS(treg, szreg, reg);
1458 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1459 		dt_regset_free(drp, szreg);
1460 	} else {
1461 		int szreg;
1462 
1463 		/*
1464 		 * If it's anything else then we'll just bcopy it.
1465 		 */
1466 		szreg = dt_regset_alloc(drp);
1467 		dt_cg_setx(dlp, szreg, size);
1468 		dt_irlist_append(dlp,
1469 		    dt_cg_node_alloc(DT_LBL_NONE, DIF_INSTR_FLUSHTS));
1470 		instr = DIF_INSTR_PUSHTS(DIF_OP_PUSHTV, DIF_TYPE_CTF,
1471 		    DIF_REG_R0, treg);
1472 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1473 		instr = DIF_INSTR_PUSHTS(DIF_OP_PUSHTV, DIF_TYPE_CTF,
1474 		    DIF_REG_R0, reg);
1475 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1476 		instr = DIF_INSTR_PUSHTS(DIF_OP_PUSHTV, DIF_TYPE_CTF,
1477 		    DIF_REG_R0, szreg);
1478 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1479 		instr = DIF_INSTR_CALL(DIF_SUBR_BCOPY, szreg);
1480 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1481 		dt_regset_free(drp, szreg);
1482 	}
1483 
1484 	dt_regset_free(drp, reg);
1485 	dt_regset_free(drp, treg);
1486 
1487 	return (0);
1488 }
1489 
1490 /*
1491  * If we're expanding a translated type, we create an appropriately sized
1492  * buffer with alloca() and then translate each member into it.
1493  */
1494 static int
1495 dt_cg_xlate_expand(dt_node_t *dnp, dt_ident_t *idp, dt_irlist_t *dlp,
1496     dt_regset_t *drp)
1497 {
1498 	dt_xlmemb_t dlm;
1499 	uint32_t instr;
1500 	int dreg;
1501 	size_t size;
1502 
1503 	dreg = dt_regset_alloc(drp);
1504 	size = ctf_type_size(dnp->dn_ident->di_ctfp, dnp->dn_ident->di_type);
1505 
1506 	/* Call alloca() to create the buffer. */
1507 	dt_cg_setx(dlp, dreg, size);
1508 
1509 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, DIF_INSTR_FLUSHTS));
1510 
1511 	instr = DIF_INSTR_PUSHTS(DIF_OP_PUSHTV, DIF_TYPE_CTF, DIF_REG_R0, dreg);
1512 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1513 
1514 	instr = DIF_INSTR_CALL(DIF_SUBR_ALLOCA, dreg);
1515 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1516 
1517 	/* Generate the translation for each member. */
1518 	dlm.dtxl_idp = idp;
1519 	dlm.dtxl_dlp = dlp;
1520 	dlm.dtxl_drp = drp;
1521 	dlm.dtxl_sreg = dnp->dn_reg;
1522 	dlm.dtxl_dreg = dreg;
1523 	(void) ctf_member_iter(dnp->dn_ident->di_ctfp,
1524 	    dnp->dn_ident->di_type, dt_cg_xlate_member,
1525 	    &dlm);
1526 
1527 	return (dreg);
1528 }
1529 
1530 static void
1531 dt_cg_node(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
1532 {
1533 	ctf_file_t *ctfp = dnp->dn_ctfp;
1534 	ctf_file_t *octfp;
1535 	ctf_membinfo_t m;
1536 	ctf_id_t type;
1537 
1538 	dif_instr_t instr;
1539 	dt_ident_t *idp;
1540 	ssize_t stroff;
1541 	uint_t op;
1542 
1543 	switch (dnp->dn_op) {
1544 	case DT_TOK_COMMA:
1545 		dt_cg_node(dnp->dn_left, dlp, drp);
1546 		dt_regset_free(drp, dnp->dn_left->dn_reg);
1547 		dt_cg_node(dnp->dn_right, dlp, drp);
1548 		dnp->dn_reg = dnp->dn_right->dn_reg;
1549 		break;
1550 
1551 	case DT_TOK_ASGN:
1552 		dt_cg_node(dnp->dn_right, dlp, drp);
1553 		dnp->dn_reg = dnp->dn_right->dn_reg;
1554 		dt_cg_asgn_op(dnp, dlp, drp);
1555 		break;
1556 
1557 	case DT_TOK_ADD_EQ:
1558 		dt_cg_arithmetic_op(dnp, dlp, drp, DIF_OP_ADD);
1559 		dt_cg_asgn_op(dnp, dlp, drp);
1560 		break;
1561 
1562 	case DT_TOK_SUB_EQ:
1563 		dt_cg_arithmetic_op(dnp, dlp, drp, DIF_OP_SUB);
1564 		dt_cg_asgn_op(dnp, dlp, drp);
1565 		break;
1566 
1567 	case DT_TOK_MUL_EQ:
1568 		dt_cg_arithmetic_op(dnp, dlp, drp, DIF_OP_MUL);
1569 		dt_cg_asgn_op(dnp, dlp, drp);
1570 		break;
1571 
1572 	case DT_TOK_DIV_EQ:
1573 		dt_cg_arithmetic_op(dnp, dlp, drp,
1574 		    (dnp->dn_flags & DT_NF_SIGNED) ? DIF_OP_SDIV : DIF_OP_UDIV);
1575 		dt_cg_asgn_op(dnp, dlp, drp);
1576 		break;
1577 
1578 	case DT_TOK_MOD_EQ:
1579 		dt_cg_arithmetic_op(dnp, dlp, drp,
1580 		    (dnp->dn_flags & DT_NF_SIGNED) ? DIF_OP_SREM : DIF_OP_UREM);
1581 		dt_cg_asgn_op(dnp, dlp, drp);
1582 		break;
1583 
1584 	case DT_TOK_AND_EQ:
1585 		dt_cg_arithmetic_op(dnp, dlp, drp, DIF_OP_AND);
1586 		dt_cg_asgn_op(dnp, dlp, drp);
1587 		break;
1588 
1589 	case DT_TOK_XOR_EQ:
1590 		dt_cg_arithmetic_op(dnp, dlp, drp, DIF_OP_XOR);
1591 		dt_cg_asgn_op(dnp, dlp, drp);
1592 		break;
1593 
1594 	case DT_TOK_OR_EQ:
1595 		dt_cg_arithmetic_op(dnp, dlp, drp, DIF_OP_OR);
1596 		dt_cg_asgn_op(dnp, dlp, drp);
1597 		break;
1598 
1599 	case DT_TOK_LSH_EQ:
1600 		dt_cg_arithmetic_op(dnp, dlp, drp, DIF_OP_SLL);
1601 		dt_cg_asgn_op(dnp, dlp, drp);
1602 		break;
1603 
1604 	case DT_TOK_RSH_EQ:
1605 		dt_cg_arithmetic_op(dnp, dlp, drp,
1606 		    (dnp->dn_flags & DT_NF_SIGNED) ? DIF_OP_SRA : DIF_OP_SRL);
1607 		dt_cg_asgn_op(dnp, dlp, drp);
1608 		break;
1609 
1610 	case DT_TOK_QUESTION:
1611 		dt_cg_ternary_op(dnp, dlp, drp);
1612 		break;
1613 
1614 	case DT_TOK_LOR:
1615 		dt_cg_logical_or(dnp, dlp, drp);
1616 		break;
1617 
1618 	case DT_TOK_LXOR:
1619 		dt_cg_logical_xor(dnp, dlp, drp);
1620 		break;
1621 
1622 	case DT_TOK_LAND:
1623 		dt_cg_logical_and(dnp, dlp, drp);
1624 		break;
1625 
1626 	case DT_TOK_BOR:
1627 		dt_cg_arithmetic_op(dnp, dlp, drp, DIF_OP_OR);
1628 		break;
1629 
1630 	case DT_TOK_XOR:
1631 		dt_cg_arithmetic_op(dnp, dlp, drp, DIF_OP_XOR);
1632 		break;
1633 
1634 	case DT_TOK_BAND:
1635 		dt_cg_arithmetic_op(dnp, dlp, drp, DIF_OP_AND);
1636 		break;
1637 
1638 	case DT_TOK_EQU:
1639 		dt_cg_compare_op(dnp, dlp, drp, DIF_OP_BE);
1640 		break;
1641 
1642 	case DT_TOK_NEQ:
1643 		dt_cg_compare_op(dnp, dlp, drp, DIF_OP_BNE);
1644 		break;
1645 
1646 	case DT_TOK_LT:
1647 		dt_cg_compare_op(dnp, dlp, drp,
1648 		    dt_cg_compare_signed(dnp) ? DIF_OP_BL : DIF_OP_BLU);
1649 		break;
1650 
1651 	case DT_TOK_LE:
1652 		dt_cg_compare_op(dnp, dlp, drp,
1653 		    dt_cg_compare_signed(dnp) ? DIF_OP_BLE : DIF_OP_BLEU);
1654 		break;
1655 
1656 	case DT_TOK_GT:
1657 		dt_cg_compare_op(dnp, dlp, drp,
1658 		    dt_cg_compare_signed(dnp) ? DIF_OP_BG : DIF_OP_BGU);
1659 		break;
1660 
1661 	case DT_TOK_GE:
1662 		dt_cg_compare_op(dnp, dlp, drp,
1663 		    dt_cg_compare_signed(dnp) ? DIF_OP_BGE : DIF_OP_BGEU);
1664 		break;
1665 
1666 	case DT_TOK_LSH:
1667 		dt_cg_arithmetic_op(dnp, dlp, drp, DIF_OP_SLL);
1668 		break;
1669 
1670 	case DT_TOK_RSH:
1671 		dt_cg_arithmetic_op(dnp, dlp, drp,
1672 		    (dnp->dn_flags & DT_NF_SIGNED) ? DIF_OP_SRA : DIF_OP_SRL);
1673 		break;
1674 
1675 	case DT_TOK_ADD:
1676 		dt_cg_arithmetic_op(dnp, dlp, drp, DIF_OP_ADD);
1677 		break;
1678 
1679 	case DT_TOK_SUB:
1680 		dt_cg_arithmetic_op(dnp, dlp, drp, DIF_OP_SUB);
1681 		break;
1682 
1683 	case DT_TOK_MUL:
1684 		dt_cg_arithmetic_op(dnp, dlp, drp, DIF_OP_MUL);
1685 		break;
1686 
1687 	case DT_TOK_DIV:
1688 		dt_cg_arithmetic_op(dnp, dlp, drp,
1689 		    (dnp->dn_flags & DT_NF_SIGNED) ? DIF_OP_SDIV : DIF_OP_UDIV);
1690 		break;
1691 
1692 	case DT_TOK_MOD:
1693 		dt_cg_arithmetic_op(dnp, dlp, drp,
1694 		    (dnp->dn_flags & DT_NF_SIGNED) ? DIF_OP_SREM : DIF_OP_UREM);
1695 		break;
1696 
1697 	case DT_TOK_LNEG:
1698 		dt_cg_logical_neg(dnp, dlp, drp);
1699 		break;
1700 
1701 	case DT_TOK_BNEG:
1702 		dt_cg_node(dnp->dn_child, dlp, drp);
1703 		dnp->dn_reg = dnp->dn_child->dn_reg;
1704 		instr = DIF_INSTR_NOT(dnp->dn_reg, dnp->dn_reg);
1705 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1706 		break;
1707 
1708 	case DT_TOK_PREINC:
1709 		dt_cg_prearith_op(dnp, dlp, drp, DIF_OP_ADD);
1710 		break;
1711 
1712 	case DT_TOK_POSTINC:
1713 		dt_cg_postarith_op(dnp, dlp, drp, DIF_OP_ADD);
1714 		break;
1715 
1716 	case DT_TOK_PREDEC:
1717 		dt_cg_prearith_op(dnp, dlp, drp, DIF_OP_SUB);
1718 		break;
1719 
1720 	case DT_TOK_POSTDEC:
1721 		dt_cg_postarith_op(dnp, dlp, drp, DIF_OP_SUB);
1722 		break;
1723 
1724 	case DT_TOK_IPOS:
1725 		dt_cg_node(dnp->dn_child, dlp, drp);
1726 		dnp->dn_reg = dnp->dn_child->dn_reg;
1727 		break;
1728 
1729 	case DT_TOK_INEG:
1730 		dt_cg_node(dnp->dn_child, dlp, drp);
1731 		dnp->dn_reg = dnp->dn_child->dn_reg;
1732 
1733 		instr = DIF_INSTR_FMT(DIF_OP_SUB, DIF_REG_R0,
1734 		    dnp->dn_reg, dnp->dn_reg);
1735 
1736 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1737 		break;
1738 
1739 	case DT_TOK_DEREF:
1740 		dt_cg_node(dnp->dn_child, dlp, drp);
1741 		dnp->dn_reg = dnp->dn_child->dn_reg;
1742 
1743 		if (dt_node_is_dynamic(dnp->dn_child)) {
1744 			int reg;
1745 			idp = dt_node_resolve(dnp->dn_child, DT_IDENT_XLPTR);
1746 			assert(idp != NULL);
1747 			reg = dt_cg_xlate_expand(dnp, idp, dlp, drp);
1748 
1749 			dt_regset_free(drp, dnp->dn_child->dn_reg);
1750 			dnp->dn_reg = reg;
1751 
1752 		} else if (!(dnp->dn_flags & DT_NF_REF)) {
1753 			uint_t ubit = dnp->dn_flags & DT_NF_USERLAND;
1754 
1755 			/*
1756 			 * Save and restore DT_NF_USERLAND across dt_cg_load():
1757 			 * we need the sign bit from dnp and the user bit from
1758 			 * dnp->dn_child in order to get the proper opcode.
1759 			 */
1760 			dnp->dn_flags |=
1761 			    (dnp->dn_child->dn_flags & DT_NF_USERLAND);
1762 
1763 			instr = DIF_INSTR_LOAD(dt_cg_load(dnp, ctfp,
1764 			    dnp->dn_type), dnp->dn_reg, dnp->dn_reg);
1765 
1766 			dnp->dn_flags &= ~DT_NF_USERLAND;
1767 			dnp->dn_flags |= ubit;
1768 
1769 			dt_irlist_append(dlp,
1770 			    dt_cg_node_alloc(DT_LBL_NONE, instr));
1771 		}
1772 		break;
1773 
1774 	case DT_TOK_ADDROF: {
1775 		uint_t rbit = dnp->dn_child->dn_flags & DT_NF_REF;
1776 
1777 		dnp->dn_child->dn_flags |= DT_NF_REF; /* force pass-by-ref */
1778 		dt_cg_node(dnp->dn_child, dlp, drp);
1779 		dnp->dn_reg = dnp->dn_child->dn_reg;
1780 
1781 		dnp->dn_child->dn_flags &= ~DT_NF_REF;
1782 		dnp->dn_child->dn_flags |= rbit;
1783 		break;
1784 	}
1785 
1786 	case DT_TOK_SIZEOF: {
1787 		size_t size = dt_node_sizeof(dnp->dn_child);
1788 		dnp->dn_reg = dt_regset_alloc(drp);
1789 		assert(size != 0);
1790 		dt_cg_setx(dlp, dnp->dn_reg, size);
1791 		break;
1792 	}
1793 
1794 	case DT_TOK_STRINGOF:
1795 		dt_cg_node(dnp->dn_child, dlp, drp);
1796 		dnp->dn_reg = dnp->dn_child->dn_reg;
1797 		break;
1798 
1799 	case DT_TOK_XLATE:
1800 		/*
1801 		 * An xlate operator appears in either an XLATOR, indicating a
1802 		 * reference to a dynamic translator, or an OP2, indicating
1803 		 * use of the xlate operator in the user's program.  For the
1804 		 * dynamic case, generate an xlate opcode with a reference to
1805 		 * the corresponding member, pre-computed for us in dn_members.
1806 		 */
1807 		if (dnp->dn_kind == DT_NODE_XLATOR) {
1808 			dt_xlator_t *dxp = dnp->dn_xlator;
1809 
1810 			assert(dxp->dx_ident->di_flags & DT_IDFLG_CGREG);
1811 			assert(dxp->dx_ident->di_id != 0);
1812 
1813 			dnp->dn_reg = dt_regset_alloc(drp);
1814 
1815 			if (dxp->dx_arg == -1) {
1816 				instr = DIF_INSTR_MOV(
1817 				    dxp->dx_ident->di_id, dnp->dn_reg);
1818 				dt_irlist_append(dlp,
1819 				    dt_cg_node_alloc(DT_LBL_NONE, instr));
1820 				op = DIF_OP_XLATE;
1821 			} else
1822 				op = DIF_OP_XLARG;
1823 
1824 			instr = DIF_INSTR_XLATE(op, 0, dnp->dn_reg);
1825 			dt_irlist_append(dlp,
1826 			    dt_cg_node_alloc(DT_LBL_NONE, instr));
1827 
1828 			dlp->dl_last->di_extern = dnp->dn_xmember;
1829 			break;
1830 		}
1831 
1832 		assert(dnp->dn_kind == DT_NODE_OP2);
1833 		dt_cg_node(dnp->dn_right, dlp, drp);
1834 		dnp->dn_reg = dnp->dn_right->dn_reg;
1835 		break;
1836 
1837 	case DT_TOK_LPAR:
1838 		dt_cg_node(dnp->dn_right, dlp, drp);
1839 		dnp->dn_reg = dnp->dn_right->dn_reg;
1840 		dt_cg_typecast(dnp->dn_right, dnp, dlp, drp);
1841 		break;
1842 
1843 	case DT_TOK_PTR:
1844 	case DT_TOK_DOT:
1845 		assert(dnp->dn_right->dn_kind == DT_NODE_IDENT);
1846 		dt_cg_node(dnp->dn_left, dlp, drp);
1847 
1848 		/*
1849 		 * If the left-hand side of PTR or DOT is a dynamic variable,
1850 		 * we expect it to be the output of a D translator.   In this
1851 		 * case, we look up the parse tree corresponding to the member
1852 		 * that is being accessed and run the code generator over it.
1853 		 * We then cast the result as if by the assignment operator.
1854 		 */
1855 		if ((idp = dt_node_resolve(
1856 		    dnp->dn_left, DT_IDENT_XLSOU)) != NULL ||
1857 		    (idp = dt_node_resolve(
1858 		    dnp->dn_left, DT_IDENT_XLPTR)) != NULL) {
1859 
1860 			dt_xlator_t *dxp;
1861 			dt_node_t *mnp;
1862 
1863 			dxp = idp->di_data;
1864 			mnp = dt_xlator_member(dxp, dnp->dn_right->dn_string);
1865 			assert(mnp != NULL);
1866 
1867 			dxp->dx_ident->di_flags |= DT_IDFLG_CGREG;
1868 			dxp->dx_ident->di_id = dnp->dn_left->dn_reg;
1869 
1870 			dt_cg_node(mnp->dn_membexpr, dlp, drp);
1871 			dnp->dn_reg = mnp->dn_membexpr->dn_reg;
1872 			dt_cg_typecast(mnp->dn_membexpr, dnp, dlp, drp);
1873 
1874 			dxp->dx_ident->di_flags &= ~DT_IDFLG_CGREG;
1875 			dxp->dx_ident->di_id = 0;
1876 
1877 			if (dnp->dn_left->dn_reg != -1)
1878 				dt_regset_free(drp, dnp->dn_left->dn_reg);
1879 			break;
1880 		}
1881 
1882 		ctfp = dnp->dn_left->dn_ctfp;
1883 		type = ctf_type_resolve(ctfp, dnp->dn_left->dn_type);
1884 
1885 		if (dnp->dn_op == DT_TOK_PTR) {
1886 			type = ctf_type_reference(ctfp, type);
1887 			type = ctf_type_resolve(ctfp, type);
1888 		}
1889 
1890 		if ((ctfp = dt_cg_membinfo(octfp = ctfp, type,
1891 		    dnp->dn_right->dn_string, &m)) == NULL) {
1892 			yypcb->pcb_hdl->dt_ctferr = ctf_errno(octfp);
1893 			longjmp(yypcb->pcb_jmpbuf, EDT_CTF);
1894 		}
1895 
1896 		if (m.ctm_offset != 0) {
1897 			int reg;
1898 
1899 			reg = dt_regset_alloc(drp);
1900 
1901 			/*
1902 			 * If the offset is not aligned on a byte boundary, it
1903 			 * is a bit-field member and we will extract the value
1904 			 * bits below after we generate the appropriate load.
1905 			 */
1906 			dt_cg_setx(dlp, reg, m.ctm_offset / NBBY);
1907 
1908 			instr = DIF_INSTR_FMT(DIF_OP_ADD,
1909 			    dnp->dn_left->dn_reg, reg, dnp->dn_left->dn_reg);
1910 
1911 			dt_irlist_append(dlp,
1912 			    dt_cg_node_alloc(DT_LBL_NONE, instr));
1913 			dt_regset_free(drp, reg);
1914 		}
1915 
1916 		if (!(dnp->dn_flags & DT_NF_REF)) {
1917 			uint_t ubit = dnp->dn_flags & DT_NF_USERLAND;
1918 
1919 			/*
1920 			 * Save and restore DT_NF_USERLAND across dt_cg_load():
1921 			 * we need the sign bit from dnp and the user bit from
1922 			 * dnp->dn_left in order to get the proper opcode.
1923 			 */
1924 			dnp->dn_flags |=
1925 			    (dnp->dn_left->dn_flags & DT_NF_USERLAND);
1926 
1927 			instr = DIF_INSTR_LOAD(dt_cg_load(dnp,
1928 			    ctfp, m.ctm_type), dnp->dn_left->dn_reg,
1929 			    dnp->dn_left->dn_reg);
1930 
1931 			dnp->dn_flags &= ~DT_NF_USERLAND;
1932 			dnp->dn_flags |= ubit;
1933 
1934 			dt_irlist_append(dlp,
1935 			    dt_cg_node_alloc(DT_LBL_NONE, instr));
1936 
1937 			if (dnp->dn_flags & DT_NF_BITFIELD)
1938 				dt_cg_field_get(dnp, dlp, drp, ctfp, &m);
1939 		}
1940 
1941 		dnp->dn_reg = dnp->dn_left->dn_reg;
1942 		break;
1943 
1944 	case DT_TOK_STRING:
1945 		dnp->dn_reg = dt_regset_alloc(drp);
1946 
1947 		assert(dnp->dn_kind == DT_NODE_STRING);
1948 		stroff = dt_strtab_insert(yypcb->pcb_strtab, dnp->dn_string);
1949 
1950 		if (stroff == -1L)
1951 			longjmp(yypcb->pcb_jmpbuf, EDT_NOMEM);
1952 		if (stroff > DIF_STROFF_MAX)
1953 			longjmp(yypcb->pcb_jmpbuf, EDT_STR2BIG);
1954 
1955 		instr = DIF_INSTR_SETS((ulong_t)stroff, dnp->dn_reg);
1956 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1957 		break;
1958 
1959 	case DT_TOK_IDENT:
1960 		/*
1961 		 * If the specified identifier is a variable on which we have
1962 		 * set the code generator register flag, then this variable
1963 		 * has already had code generated for it and saved in di_id.
1964 		 * Allocate a new register and copy the existing value to it.
1965 		 */
1966 		if (dnp->dn_kind == DT_NODE_VAR &&
1967 		    (dnp->dn_ident->di_flags & DT_IDFLG_CGREG)) {
1968 			dnp->dn_reg = dt_regset_alloc(drp);
1969 			instr = DIF_INSTR_MOV(dnp->dn_ident->di_id,
1970 			    dnp->dn_reg);
1971 			dt_irlist_append(dlp,
1972 			    dt_cg_node_alloc(DT_LBL_NONE, instr));
1973 			break;
1974 		}
1975 
1976 		/*
1977 		 * Identifiers can represent function calls, variable refs, or
1978 		 * symbols.  First we check for inlined variables, and handle
1979 		 * them by generating code for the inline parse tree.
1980 		 */
1981 		if (dnp->dn_kind == DT_NODE_VAR &&
1982 		    (dnp->dn_ident->di_flags & DT_IDFLG_INLINE)) {
1983 			dt_cg_inline(dnp, dlp, drp);
1984 			break;
1985 		}
1986 
1987 		switch (dnp->dn_kind) {
1988 		case DT_NODE_FUNC:
1989 			if ((idp = dnp->dn_ident)->di_kind != DT_IDENT_FUNC) {
1990 				dnerror(dnp, D_CG_EXPR, "%s %s( ) may not be "
1991 				    "called from a D expression (D program "
1992 				    "context required)\n",
1993 				    dt_idkind_name(idp->di_kind), idp->di_name);
1994 			}
1995 
1996 			dt_cg_arglist(dnp->dn_ident, dnp->dn_args, dlp, drp);
1997 
1998 			dnp->dn_reg = dt_regset_alloc(drp);
1999 			instr = DIF_INSTR_CALL(dnp->dn_ident->di_id,
2000 			    dnp->dn_reg);
2001 
2002 			dt_irlist_append(dlp,
2003 			    dt_cg_node_alloc(DT_LBL_NONE, instr));
2004 
2005 			break;
2006 
2007 		case DT_NODE_VAR:
2008 			if (dnp->dn_ident->di_kind == DT_IDENT_XLSOU ||
2009 			    dnp->dn_ident->di_kind == DT_IDENT_XLPTR) {
2010 				/*
2011 				 * This can only happen if we have translated
2012 				 * args[].  See dt_idcook_args() for details.
2013 				 */
2014 				assert(dnp->dn_ident->di_id == DIF_VAR_ARGS);
2015 				dt_cg_array_op(dnp, dlp, drp);
2016 				break;
2017 			}
2018 
2019 			if (dnp->dn_ident->di_kind == DT_IDENT_ARRAY) {
2020 				if (dnp->dn_ident->di_id > DIF_VAR_ARRAY_MAX)
2021 					dt_cg_assoc_op(dnp, dlp, drp);
2022 				else
2023 					dt_cg_array_op(dnp, dlp, drp);
2024 				break;
2025 			}
2026 
2027 			dnp->dn_reg = dt_regset_alloc(drp);
2028 
2029 			if (dnp->dn_ident->di_flags & DT_IDFLG_LOCAL)
2030 				op = DIF_OP_LDLS;
2031 			else if (dnp->dn_ident->di_flags & DT_IDFLG_TLS)
2032 				op = DIF_OP_LDTS;
2033 			else
2034 				op = DIF_OP_LDGS;
2035 
2036 			dnp->dn_ident->di_flags |= DT_IDFLG_DIFR;
2037 
2038 			instr = DIF_INSTR_LDV(op,
2039 			    dnp->dn_ident->di_id, dnp->dn_reg);
2040 
2041 			dt_irlist_append(dlp,
2042 			    dt_cg_node_alloc(DT_LBL_NONE, instr));
2043 			break;
2044 
2045 		case DT_NODE_SYM: {
2046 			dtrace_hdl_t *dtp = yypcb->pcb_hdl;
2047 			dtrace_syminfo_t *sip = dnp->dn_ident->di_data;
2048 			GElf_Sym sym;
2049 
2050 			if (dtrace_lookup_by_name(dtp,
2051 			    sip->dts_object, sip->dts_name, &sym, NULL) == -1) {
2052 				xyerror(D_UNKNOWN, "cg failed for symbol %s`%s:"
2053 				    " %s\n", sip->dts_object, sip->dts_name,
2054 				    dtrace_errmsg(dtp, dtrace_errno(dtp)));
2055 			}
2056 
2057 			dnp->dn_reg = dt_regset_alloc(drp);
2058 			dt_cg_xsetx(dlp, dnp->dn_ident,
2059 			    DT_LBL_NONE, dnp->dn_reg, sym.st_value);
2060 
2061 			if (!(dnp->dn_flags & DT_NF_REF)) {
2062 				instr = DIF_INSTR_LOAD(dt_cg_load(dnp, ctfp,
2063 				    dnp->dn_type), dnp->dn_reg, dnp->dn_reg);
2064 				dt_irlist_append(dlp,
2065 				    dt_cg_node_alloc(DT_LBL_NONE, instr));
2066 			}
2067 			break;
2068 		}
2069 
2070 		default:
2071 			xyerror(D_UNKNOWN, "internal error -- node type %u is "
2072 			    "not valid for an identifier\n", dnp->dn_kind);
2073 		}
2074 		break;
2075 
2076 	case DT_TOK_INT:
2077 		dnp->dn_reg = dt_regset_alloc(drp);
2078 		dt_cg_setx(dlp, dnp->dn_reg, dnp->dn_value);
2079 		break;
2080 
2081 	default:
2082 		xyerror(D_UNKNOWN, "internal error -- token type %u is not a "
2083 		    "valid D compilation token\n", dnp->dn_op);
2084 	}
2085 }
2086 
2087 void
2088 dt_cg(dt_pcb_t *pcb, dt_node_t *dnp)
2089 {
2090 	dif_instr_t instr;
2091 	dt_xlator_t *dxp;
2092 	dt_ident_t *idp;
2093 
2094 	if (pcb->pcb_regs == NULL && (pcb->pcb_regs =
2095 	    dt_regset_create(pcb->pcb_hdl->dt_conf.dtc_difintregs)) == NULL)
2096 		longjmp(pcb->pcb_jmpbuf, EDT_NOMEM);
2097 
2098 	dt_regset_reset(pcb->pcb_regs);
2099 	(void) dt_regset_alloc(pcb->pcb_regs); /* allocate %r0 */
2100 
2101 	if (pcb->pcb_inttab != NULL)
2102 		dt_inttab_destroy(pcb->pcb_inttab);
2103 
2104 	if ((pcb->pcb_inttab = dt_inttab_create(yypcb->pcb_hdl)) == NULL)
2105 		longjmp(pcb->pcb_jmpbuf, EDT_NOMEM);
2106 
2107 	if (pcb->pcb_strtab != NULL)
2108 		dt_strtab_destroy(pcb->pcb_strtab);
2109 
2110 	if ((pcb->pcb_strtab = dt_strtab_create(BUFSIZ)) == NULL)
2111 		longjmp(pcb->pcb_jmpbuf, EDT_NOMEM);
2112 
2113 	dt_irlist_destroy(&pcb->pcb_ir);
2114 	dt_irlist_create(&pcb->pcb_ir);
2115 
2116 	assert(pcb->pcb_dret == NULL);
2117 	pcb->pcb_dret = dnp;
2118 
2119 	if (dt_node_resolve(dnp, DT_IDENT_XLPTR) != NULL) {
2120 		dnerror(dnp, D_CG_DYN, "expression cannot evaluate to result "
2121 		    "of a translated pointer\n");
2122 	}
2123 
2124 	/*
2125 	 * If we're generating code for a translator body, assign the input
2126 	 * parameter to the first available register (i.e. caller passes %r1).
2127 	 */
2128 	if (dnp->dn_kind == DT_NODE_MEMBER) {
2129 		dxp = dnp->dn_membxlator;
2130 		dnp = dnp->dn_membexpr;
2131 
2132 		dxp->dx_ident->di_flags |= DT_IDFLG_CGREG;
2133 		dxp->dx_ident->di_id = dt_regset_alloc(pcb->pcb_regs);
2134 	}
2135 
2136 	dt_cg_node(dnp, &pcb->pcb_ir, pcb->pcb_regs);
2137 
2138 	if ((idp = dt_node_resolve(dnp, DT_IDENT_XLSOU)) != NULL) {
2139 		int reg = dt_cg_xlate_expand(dnp, idp,
2140 		    &pcb->pcb_ir, pcb->pcb_regs);
2141 		dt_regset_free(pcb->pcb_regs, dnp->dn_reg);
2142 		dnp->dn_reg = reg;
2143 	}
2144 
2145 	instr = DIF_INSTR_RET(dnp->dn_reg);
2146 	dt_regset_free(pcb->pcb_regs, dnp->dn_reg);
2147 	dt_irlist_append(&pcb->pcb_ir, dt_cg_node_alloc(DT_LBL_NONE, instr));
2148 
2149 	if (dnp->dn_kind == DT_NODE_MEMBER) {
2150 		dt_regset_free(pcb->pcb_regs, dxp->dx_ident->di_id);
2151 		dxp->dx_ident->di_id = 0;
2152 		dxp->dx_ident->di_flags &= ~DT_IDFLG_CGREG;
2153 	}
2154 
2155 	dt_regset_free(pcb->pcb_regs, 0);
2156 	dt_regset_assert_free(pcb->pcb_regs);
2157 }
2158