xref: /illumos-gate/usr/src/lib/libdtrace/common/dt_cg.c (revision 0250c53ad267726f2438e3c6556199a0bbf588a2)
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  * Copyright 2022 Oxide Computer Company
32  */
33 
34 #include <sys/types.h>
35 #include <sys/sysmacros.h>
36 #include <sys/isa_defs.h>
37 
38 #include <strings.h>
39 #include <stdlib.h>
40 #include <setjmp.h>
41 #include <assert.h>
42 #include <errno.h>
43 
44 #include <dt_impl.h>
45 #include <dt_grammar.h>
46 #include <dt_parser.h>
47 #include <dt_provider.h>
48 
49 static void dt_cg_node(dt_node_t *, dt_irlist_t *, dt_regset_t *);
50 
51 static dt_irnode_t *
52 dt_cg_node_alloc(uint_t label, dif_instr_t instr)
53 {
54 	dt_irnode_t *dip = malloc(sizeof (dt_irnode_t));
55 
56 	if (dip == NULL)
57 		longjmp(yypcb->pcb_jmpbuf, EDT_NOMEM);
58 
59 	dip->di_label = label;
60 	dip->di_instr = instr;
61 	dip->di_extern = NULL;
62 	dip->di_next = NULL;
63 
64 	return (dip);
65 }
66 
67 /*
68  * Code generator wrapper function for ctf_member_info.  If we are given a
69  * reference to a forward declaration tag, search the entire type space for
70  * the actual definition and then call ctf_member_info on the result.
71  */
72 static ctf_file_t *
73 dt_cg_membinfo(ctf_file_t *fp, ctf_id_t type, const char *s, ctf_membinfo_t *mp)
74 {
75 	while (ctf_type_kind(fp, type) == CTF_K_FORWARD) {
76 		char n[DT_TYPE_NAMELEN];
77 		dtrace_typeinfo_t dtt;
78 
79 		if (ctf_type_name(fp, type, n, sizeof (n)) == NULL ||
80 		    dt_type_lookup(n, &dtt) == -1 || (
81 		    dtt.dtt_ctfp == fp && dtt.dtt_type == type))
82 			break; /* unable to improve our position */
83 
84 		fp = dtt.dtt_ctfp;
85 		type = ctf_type_resolve(fp, dtt.dtt_type);
86 	}
87 
88 	if (ctf_member_info(fp, type, s, mp) == CTF_ERR)
89 		return (NULL); /* ctf_errno is set for us */
90 
91 	return (fp);
92 }
93 
94 static void
95 dt_cg_xsetx(dt_irlist_t *dlp, dt_ident_t *idp, uint_t lbl, int reg, uint64_t x)
96 {
97 	int flag = idp != NULL ? DT_INT_PRIVATE : DT_INT_SHARED;
98 	int intoff = dt_inttab_insert(yypcb->pcb_inttab, x, flag);
99 	dif_instr_t instr = DIF_INSTR_SETX((uint_t)intoff, reg);
100 
101 	if (intoff == -1)
102 		longjmp(yypcb->pcb_jmpbuf, EDT_NOMEM);
103 
104 	if (intoff > DIF_INTOFF_MAX)
105 		longjmp(yypcb->pcb_jmpbuf, EDT_INT2BIG);
106 
107 	dt_irlist_append(dlp, dt_cg_node_alloc(lbl, instr));
108 
109 	if (idp != NULL)
110 		dlp->dl_last->di_extern = idp;
111 }
112 
113 static void
114 dt_cg_setx(dt_irlist_t *dlp, int reg, uint64_t x)
115 {
116 	dt_cg_xsetx(dlp, NULL, DT_LBL_NONE, reg, x);
117 }
118 
119 /*
120  * When loading bit-fields, we want to convert a byte count in the range
121  * 1-8 to the closest power of 2 (e.g. 3->4, 5->8, etc).  The clp2() function
122  * is a clever implementation from "Hacker's Delight" by Henry Warren, Jr.
123  */
124 static size_t
125 clp2(size_t x)
126 {
127 	x--;
128 
129 	x |= (x >> 1);
130 	x |= (x >> 2);
131 	x |= (x >> 4);
132 	x |= (x >> 8);
133 	x |= (x >> 16);
134 
135 	return (x + 1);
136 }
137 
138 /*
139  * Lookup the correct load opcode to use for the specified node and CTF type.
140  * We determine the size and convert it to a 3-bit index.  Our lookup table
141  * is constructed to use a 5-bit index, consisting of the 3-bit size 0-7, a
142  * bit for the sign, and a bit for userland address.  For example, a 4-byte
143  * signed load from userland would be at the following table index:
144  * user=1 sign=1 size=4 => binary index 11011 = decimal index 27
145  */
146 static uint_t
147 dt_cg_load(dt_node_t *dnp, ctf_file_t *ctfp, ctf_id_t type)
148 {
149 	static const uint_t ops[] = {
150 		DIF_OP_LDUB,	DIF_OP_LDUH,	0,	DIF_OP_LDUW,
151 		0,		0,		0,	DIF_OP_LDX,
152 		DIF_OP_LDSB,	DIF_OP_LDSH,	0,	DIF_OP_LDSW,
153 		0,		0,		0,	DIF_OP_LDX,
154 		DIF_OP_ULDUB,	DIF_OP_ULDUH,	0,	DIF_OP_ULDUW,
155 		0,		0,		0,	DIF_OP_ULDX,
156 		DIF_OP_ULDSB,	DIF_OP_ULDSH,	0,	DIF_OP_ULDSW,
157 		0,		0,		0,	DIF_OP_ULDX,
158 	};
159 
160 	ctf_encoding_t e;
161 	ssize_t size;
162 
163 	/*
164 	 * If we're loading a bit-field, we find the power-of-two that spans the
165 	 * full value. To do this we count the number of bytes that contain a
166 	 * portion of the bit-field.
167 	 */
168 	if ((dnp->dn_flags & DT_NF_BITFIELD) &&
169 	    ctf_type_encoding(ctfp, type, &e) != CTF_ERR) {
170 		uint_t nbits = e.cte_bits + (dnp->dn_bitoff % NBBY);
171 		size = clp2(P2ROUNDUP(nbits, NBBY) / NBBY);
172 	} else {
173 		size = ctf_type_size(ctfp, type);
174 	}
175 
176 	if (size < 1 || size > 8 || (size & (size - 1)) != 0) {
177 		xyerror(D_UNKNOWN, "internal error -- cg cannot load "
178 		    "size %ld when passed by value\n", (long)size);
179 	}
180 
181 	size--; /* convert size to 3-bit index */
182 
183 	if (dnp->dn_flags & DT_NF_SIGNED)
184 		size |= 0x08;
185 	if (dnp->dn_flags & DT_NF_USERLAND)
186 		size |= 0x10;
187 
188 	return (ops[size]);
189 }
190 
191 static void
192 dt_cg_ptrsize(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp,
193     uint_t op, int dreg)
194 {
195 	ctf_file_t *ctfp = dnp->dn_ctfp;
196 	ctf_arinfo_t r;
197 	dif_instr_t instr;
198 	ctf_id_t type;
199 	uint_t kind;
200 	ssize_t size;
201 	int sreg;
202 
203 	type = ctf_type_resolve(ctfp, dnp->dn_type);
204 	kind = ctf_type_kind(ctfp, type);
205 	assert(kind == CTF_K_POINTER || kind == CTF_K_ARRAY);
206 
207 	if (kind == CTF_K_ARRAY) {
208 		if (ctf_array_info(ctfp, type, &r) != 0) {
209 			yypcb->pcb_hdl->dt_ctferr = ctf_errno(ctfp);
210 			longjmp(yypcb->pcb_jmpbuf, EDT_CTF);
211 		}
212 		type = r.ctr_contents;
213 	} else
214 		type = ctf_type_reference(ctfp, type);
215 
216 	if ((size = ctf_type_size(ctfp, type)) == 1)
217 		return; /* multiply or divide by one can be omitted */
218 
219 	sreg = dt_regset_alloc(drp);
220 	dt_cg_setx(dlp, sreg, size);
221 	instr = DIF_INSTR_FMT(op, dreg, sreg, dreg);
222 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
223 	dt_regset_free(drp, sreg);
224 }
225 
226 /*
227  * If the result of a "." or "->" operation is a bit-field, we use this routine
228  * to generate an epilogue to the load instruction that extracts the value.  In
229  * the diagrams below the "ld??" is the load instruction that is generated to
230  * load the containing word that is generating prior to calling this function.
231  *
232  * Epilogue for unsigned fields:	Epilogue for signed fields:
233  *
234  * ldu?	[r1], r1			lds? [r1], r1
235  * setx	USHIFT, r2			setx 64 - SSHIFT, r2
236  * srl	r1, r2, r1			sll  r1, r2, r1
237  * setx	(1 << bits) - 1, r2		setx 64 - bits, r2
238  * and	r1, r2, r1			sra  r1, r2, r1
239  *
240  * The *SHIFT constants above changes value depending on the endian-ness of our
241  * target architecture.  Refer to the comments below for more details.
242  */
243 static void
244 dt_cg_field_get(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp,
245     ctf_file_t *fp, const ctf_membinfo_t *mp)
246 {
247 	ctf_encoding_t e;
248 	dif_instr_t instr;
249 	uint64_t shift;
250 	int r1, r2;
251 
252 	if (ctf_type_encoding(fp, mp->ctm_type, &e) != 0 || e.cte_bits > 64) {
253 		xyerror(D_UNKNOWN, "cg: bad field: off %lu type <%ld> "
254 		    "bits %u\n", mp->ctm_offset, mp->ctm_type, e.cte_bits);
255 	}
256 
257 	assert(dnp->dn_op == DT_TOK_PTR || dnp->dn_op == DT_TOK_DOT);
258 	r1 = dnp->dn_left->dn_reg;
259 	r2 = dt_regset_alloc(drp);
260 
261 	/*
262 	 * On little-endian architectures, ctm_offset counts from the right so
263 	 * ctm_offset % NBBY itself is the amount we want to shift right to
264 	 * move the value bits to the little end of the register to mask them.
265 	 * On big-endian architectures, ctm_offset counts from the left so we
266 	 * must subtract (ctm_offset % NBBY + cte_bits) from the size in bits
267 	 * we used for the load.  The size of our load in turn is found by
268 	 * rounding cte_bits up to a byte boundary and then finding the
269 	 * nearest power of two to this value (see clp2(), above).  These
270 	 * properties are used to compute shift as USHIFT or SSHIFT, below.
271 	 */
272 	if (dnp->dn_flags & DT_NF_SIGNED) {
273 #ifdef _BIG_ENDIAN
274 		shift = clp2(P2ROUNDUP(e.cte_bits, NBBY) / NBBY) * NBBY -
275 		    mp->ctm_offset % NBBY;
276 #else
277 		shift = mp->ctm_offset % NBBY + e.cte_bits;
278 #endif
279 		dt_cg_setx(dlp, r2, 64 - shift);
280 		instr = DIF_INSTR_FMT(DIF_OP_SLL, r1, r2, r1);
281 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
282 
283 		dt_cg_setx(dlp, r2, 64 - e.cte_bits);
284 		instr = DIF_INSTR_FMT(DIF_OP_SRA, r1, r2, r1);
285 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
286 	} else {
287 #ifdef _BIG_ENDIAN
288 		shift = clp2(P2ROUNDUP(e.cte_bits, NBBY) / NBBY) * NBBY -
289 		    (mp->ctm_offset % NBBY + e.cte_bits);
290 #else
291 		shift = mp->ctm_offset % NBBY;
292 #endif
293 		dt_cg_setx(dlp, r2, shift);
294 		instr = DIF_INSTR_FMT(DIF_OP_SRL, r1, r2, r1);
295 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
296 
297 		dt_cg_setx(dlp, r2, (1ULL << e.cte_bits) - 1);
298 		instr = DIF_INSTR_FMT(DIF_OP_AND, r1, r2, r1);
299 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
300 	}
301 
302 	dt_regset_free(drp, r2);
303 }
304 
305 /*
306  * If the destination of a store operation is a bit-field, we use this routine
307  * to generate a prologue to the store instruction that loads the surrounding
308  * bits, clears the destination field, and ORs in the new value of the field.
309  * In the diagram below the "st?" is the store instruction that is generated to
310  * store the containing word that is generating after calling this function.
311  *
312  * ld	[dst->dn_reg], r1
313  * setx	~(((1 << cte_bits) - 1) << (ctm_offset % NBBY)), r2
314  * and	r1, r2, r1
315  *
316  * setx	(1 << cte_bits) - 1, r2
317  * and	src->dn_reg, r2, r2
318  * setx ctm_offset % NBBY, r3
319  * sll	r2, r3, r2
320  *
321  * or	r1, r2, r1
322  * st?	r1, [dst->dn_reg]
323  *
324  * This routine allocates a new register to hold the value to be stored and
325  * returns it.  The caller is responsible for freeing this register later.
326  */
327 static int
328 dt_cg_field_set(dt_node_t *src, dt_irlist_t *dlp,
329     dt_regset_t *drp, dt_node_t *dst)
330 {
331 	uint64_t cmask, fmask, shift;
332 	dif_instr_t instr;
333 	int r1, r2, r3;
334 
335 	ctf_membinfo_t m;
336 	ctf_encoding_t e;
337 	ctf_file_t *fp, *ofp;
338 	ctf_id_t type;
339 
340 	assert(dst->dn_op == DT_TOK_PTR || dst->dn_op == DT_TOK_DOT);
341 	assert(dst->dn_right->dn_kind == DT_NODE_IDENT);
342 
343 	fp = dst->dn_left->dn_ctfp;
344 	type = ctf_type_resolve(fp, dst->dn_left->dn_type);
345 
346 	if (dst->dn_op == DT_TOK_PTR) {
347 		type = ctf_type_reference(fp, type);
348 		type = ctf_type_resolve(fp, type);
349 	}
350 
351 	if ((fp = dt_cg_membinfo(ofp = fp, type,
352 	    dst->dn_right->dn_string, &m)) == NULL) {
353 		yypcb->pcb_hdl->dt_ctferr = ctf_errno(ofp);
354 		longjmp(yypcb->pcb_jmpbuf, EDT_CTF);
355 	}
356 
357 	if (ctf_type_encoding(fp, m.ctm_type, &e) != 0 || e.cte_bits > 64) {
358 		xyerror(D_UNKNOWN, "cg: bad field: off %lu type <%ld> "
359 		    "bits %u\n", m.ctm_offset, m.ctm_type, e.cte_bits);
360 	}
361 
362 	r1 = dt_regset_alloc(drp);
363 	r2 = dt_regset_alloc(drp);
364 	r3 = dt_regset_alloc(drp);
365 
366 	/*
367 	 * Compute shifts and masks.  We need to compute "shift" as the amount
368 	 * we need to shift left to position our field in the containing word.
369 	 * Refer to the comments in dt_cg_field_get(), above, for more info.
370 	 * We then compute fmask as the mask that truncates the value in the
371 	 * input register to width cte_bits, and cmask as the mask used to
372 	 * pass through the containing bits and zero the field bits.
373 	 */
374 #ifdef _BIG_ENDIAN
375 	shift = clp2(P2ROUNDUP(e.cte_bits, NBBY) / NBBY) * NBBY -
376 	    (m.ctm_offset % NBBY + e.cte_bits);
377 #else
378 	shift = m.ctm_offset % NBBY;
379 #endif
380 	fmask = (1ULL << e.cte_bits) - 1;
381 	cmask = ~(fmask << shift);
382 
383 	instr = DIF_INSTR_LOAD(
384 	    dt_cg_load(dst, fp, m.ctm_type), dst->dn_reg, r1);
385 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
386 
387 	dt_cg_setx(dlp, r2, cmask);
388 	instr = DIF_INSTR_FMT(DIF_OP_AND, r1, r2, r1);
389 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
390 
391 	dt_cg_setx(dlp, r2, fmask);
392 	instr = DIF_INSTR_FMT(DIF_OP_AND, src->dn_reg, r2, r2);
393 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
394 
395 	dt_cg_setx(dlp, r3, shift);
396 	instr = DIF_INSTR_FMT(DIF_OP_SLL, r2, r3, r2);
397 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
398 
399 	instr = DIF_INSTR_FMT(DIF_OP_OR, r1, r2, r1);
400 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
401 
402 	dt_regset_free(drp, r3);
403 	dt_regset_free(drp, r2);
404 
405 	return (r1);
406 }
407 
408 static void
409 dt_cg_store(dt_node_t *src, dt_irlist_t *dlp, dt_regset_t *drp, dt_node_t *dst)
410 {
411 	ctf_encoding_t e;
412 	dif_instr_t instr;
413 	size_t size;
414 	int reg;
415 
416 	/*
417 	 * If we're loading a bit-field, the size of our store is found by
418 	 * rounding dst's cte_bits up to a byte boundary and then finding the
419 	 * nearest power of two to this value (see clp2(), above).
420 	 */
421 	if ((dst->dn_flags & DT_NF_BITFIELD) &&
422 	    ctf_type_encoding(dst->dn_ctfp, dst->dn_type, &e) != CTF_ERR)
423 		size = clp2(P2ROUNDUP(e.cte_bits, NBBY) / NBBY);
424 	else
425 		size = dt_node_type_size(src);
426 
427 	if (src->dn_flags & DT_NF_REF) {
428 		reg = dt_regset_alloc(drp);
429 		dt_cg_setx(dlp, reg, size);
430 		instr = DIF_INSTR_COPYS(src->dn_reg, reg, dst->dn_reg);
431 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
432 		dt_regset_free(drp, reg);
433 	} else {
434 		if (dst->dn_flags & DT_NF_BITFIELD)
435 			reg = dt_cg_field_set(src, dlp, drp, dst);
436 		else
437 			reg = src->dn_reg;
438 
439 		switch (size) {
440 		case 1:
441 			instr = DIF_INSTR_STORE(DIF_OP_STB, reg, dst->dn_reg);
442 			break;
443 		case 2:
444 			instr = DIF_INSTR_STORE(DIF_OP_STH, reg, dst->dn_reg);
445 			break;
446 		case 4:
447 			instr = DIF_INSTR_STORE(DIF_OP_STW, reg, dst->dn_reg);
448 			break;
449 		case 8:
450 			instr = DIF_INSTR_STORE(DIF_OP_STX, reg, dst->dn_reg);
451 			break;
452 		default:
453 			xyerror(D_UNKNOWN, "internal error -- cg cannot store "
454 			    "size %lu when passed by value\n", (ulong_t)size);
455 		}
456 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
457 
458 		if (dst->dn_flags & DT_NF_BITFIELD)
459 			dt_regset_free(drp, reg);
460 	}
461 }
462 
463 /*
464  * Generate code for a typecast or for argument promotion from the type of the
465  * actual to the type of the formal.  We need to generate code for casts when
466  * a scalar type is being narrowed or changing signed-ness.  We first shift the
467  * desired bits high (losing excess bits if narrowing) and then shift them down
468  * using logical shift (unsigned result) or arithmetic shift (signed result).
469  */
470 static void
471 dt_cg_typecast(const dt_node_t *src, const dt_node_t *dst,
472     dt_irlist_t *dlp, dt_regset_t *drp)
473 {
474 	size_t srcsize = dt_node_type_size(src);
475 	size_t dstsize = dt_node_type_size(dst);
476 
477 	dif_instr_t instr;
478 	int rg;
479 
480 	if (!dt_node_is_scalar(dst))
481 		return; /* not a scalar */
482 	if (dstsize == srcsize &&
483 	    ((src->dn_flags ^ dst->dn_flags) & DT_NF_SIGNED) == 0)
484 		return; /* not narrowing or changing signed-ness */
485 	if (dstsize > srcsize && (src->dn_flags & DT_NF_SIGNED) == 0)
486 		return; /* nothing to do in this case */
487 
488 	rg = dt_regset_alloc(drp);
489 
490 	if (dstsize > srcsize) {
491 		int n = sizeof (uint64_t) * NBBY - srcsize * NBBY;
492 		int s = (dstsize - srcsize) * NBBY;
493 
494 		dt_cg_setx(dlp, rg, n);
495 
496 		instr = DIF_INSTR_FMT(DIF_OP_SLL, src->dn_reg, rg, dst->dn_reg);
497 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
498 
499 		if ((dst->dn_flags & DT_NF_SIGNED) || n == s) {
500 			instr = DIF_INSTR_FMT(DIF_OP_SRA,
501 			    dst->dn_reg, rg, dst->dn_reg);
502 			dt_irlist_append(dlp,
503 			    dt_cg_node_alloc(DT_LBL_NONE, instr));
504 		} else {
505 			dt_cg_setx(dlp, rg, s);
506 			instr = DIF_INSTR_FMT(DIF_OP_SRA,
507 			    dst->dn_reg, rg, dst->dn_reg);
508 			dt_irlist_append(dlp,
509 			    dt_cg_node_alloc(DT_LBL_NONE, instr));
510 			dt_cg_setx(dlp, rg, n - s);
511 			instr = DIF_INSTR_FMT(DIF_OP_SRL,
512 			    dst->dn_reg, rg, dst->dn_reg);
513 			dt_irlist_append(dlp,
514 			    dt_cg_node_alloc(DT_LBL_NONE, instr));
515 		}
516 	} else if (dstsize != sizeof (uint64_t)) {
517 		int n = sizeof (uint64_t) * NBBY - dstsize * NBBY;
518 
519 		dt_cg_setx(dlp, rg, n);
520 
521 		instr = DIF_INSTR_FMT(DIF_OP_SLL, src->dn_reg, rg, dst->dn_reg);
522 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
523 
524 		instr = DIF_INSTR_FMT((dst->dn_flags & DT_NF_SIGNED) ?
525 		    DIF_OP_SRA : DIF_OP_SRL, dst->dn_reg, rg, dst->dn_reg);
526 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
527 	}
528 
529 	dt_regset_free(drp, rg);
530 }
531 
532 /*
533  * Generate code to push the specified argument list on to the tuple stack.
534  * We use this routine for handling subroutine calls and associative arrays.
535  * We must first generate code for all subexpressions before loading the stack
536  * because any subexpression could itself require the use of the tuple stack.
537  * This holds a number of registers equal to the number of arguments, but this
538  * is not a huge problem because the number of arguments can't exceed the
539  * number of tuple register stack elements anyway.  At most one extra register
540  * is required (either by dt_cg_typecast() or for dtdt_size, below).  This
541  * implies that a DIF implementation should offer a number of general purpose
542  * registers at least one greater than the number of tuple registers.
543  */
544 static void
545 dt_cg_arglist(dt_ident_t *idp, dt_node_t *args,
546     dt_irlist_t *dlp, dt_regset_t *drp)
547 {
548 	const dt_idsig_t *isp = idp->di_data;
549 	dt_node_t *dnp;
550 	int i = 0;
551 
552 	for (dnp = args; dnp != NULL; dnp = dnp->dn_list)
553 		dt_cg_node(dnp, dlp, drp);
554 
555 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, DIF_INSTR_FLUSHTS));
556 
557 	for (dnp = args; dnp != NULL; dnp = dnp->dn_list, i++) {
558 		dtrace_diftype_t t;
559 		dif_instr_t instr;
560 		uint_t op;
561 		int reg;
562 
563 		dt_node_diftype(yypcb->pcb_hdl, dnp, &t);
564 
565 		isp->dis_args[i].dn_reg = dnp->dn_reg; /* re-use register */
566 		dt_cg_typecast(dnp, &isp->dis_args[i], dlp, drp);
567 		isp->dis_args[i].dn_reg = -1;
568 
569 		if (t.dtdt_flags & DIF_TF_BYREF) {
570 			op = DIF_OP_PUSHTR;
571 			if (t.dtdt_size != 0) {
572 				reg = dt_regset_alloc(drp);
573 				dt_cg_setx(dlp, reg, t.dtdt_size);
574 			} else {
575 				reg = DIF_REG_R0;
576 			}
577 		} else {
578 			op = DIF_OP_PUSHTV;
579 			reg = DIF_REG_R0;
580 		}
581 
582 		instr = DIF_INSTR_PUSHTS(op, t.dtdt_kind, reg, dnp->dn_reg);
583 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
584 		dt_regset_free(drp, dnp->dn_reg);
585 
586 		if (reg != DIF_REG_R0)
587 			dt_regset_free(drp, reg);
588 	}
589 
590 	if (i > yypcb->pcb_hdl->dt_conf.dtc_diftupregs)
591 		longjmp(yypcb->pcb_jmpbuf, EDT_NOTUPREG);
592 }
593 
594 static void
595 dt_cg_arithmetic_op(dt_node_t *dnp, dt_irlist_t *dlp,
596     dt_regset_t *drp, uint_t op)
597 {
598 	int is_ptr_op = (dnp->dn_op == DT_TOK_ADD || dnp->dn_op == DT_TOK_SUB ||
599 	    dnp->dn_op == DT_TOK_ADD_EQ || dnp->dn_op == DT_TOK_SUB_EQ);
600 
601 	int lp_is_ptr = dt_node_is_pointer(dnp->dn_left);
602 	int rp_is_ptr = dt_node_is_pointer(dnp->dn_right);
603 
604 	dif_instr_t instr;
605 
606 	if (lp_is_ptr && rp_is_ptr) {
607 		assert(dnp->dn_op == DT_TOK_SUB);
608 		is_ptr_op = 0;
609 	}
610 
611 	dt_cg_node(dnp->dn_left, dlp, drp);
612 	if (is_ptr_op && rp_is_ptr)
613 		dt_cg_ptrsize(dnp, dlp, drp, DIF_OP_MUL, dnp->dn_left->dn_reg);
614 
615 	dt_cg_node(dnp->dn_right, dlp, drp);
616 	if (is_ptr_op && lp_is_ptr)
617 		dt_cg_ptrsize(dnp, dlp, drp, DIF_OP_MUL, dnp->dn_right->dn_reg);
618 
619 	instr = DIF_INSTR_FMT(op, dnp->dn_left->dn_reg,
620 	    dnp->dn_right->dn_reg, dnp->dn_left->dn_reg);
621 
622 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
623 	dt_regset_free(drp, dnp->dn_right->dn_reg);
624 	dnp->dn_reg = dnp->dn_left->dn_reg;
625 
626 	if (lp_is_ptr && rp_is_ptr)
627 		dt_cg_ptrsize(dnp->dn_right,
628 		    dlp, drp, DIF_OP_UDIV, dnp->dn_reg);
629 }
630 
631 static uint_t
632 dt_cg_stvar(const dt_ident_t *idp)
633 {
634 	static const uint_t aops[] = { DIF_OP_STGAA, DIF_OP_STTAA, DIF_OP_NOP };
635 	static const uint_t sops[] = { DIF_OP_STGS, DIF_OP_STTS, DIF_OP_STLS };
636 
637 	uint_t i = (((idp->di_flags & DT_IDFLG_LOCAL) != 0) << 1) |
638 	    ((idp->di_flags & DT_IDFLG_TLS) != 0);
639 
640 	return (idp->di_kind == DT_IDENT_ARRAY ? aops[i] : sops[i]);
641 }
642 
643 static void
644 dt_cg_prearith_op(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp, uint_t op)
645 {
646 	ctf_file_t *ctfp = dnp->dn_ctfp;
647 	dif_instr_t instr;
648 	ctf_id_t type;
649 	ssize_t size = 1;
650 	int reg;
651 
652 	if (dt_node_is_pointer(dnp)) {
653 		type = ctf_type_resolve(ctfp, dnp->dn_type);
654 		assert(ctf_type_kind(ctfp, type) == CTF_K_POINTER);
655 		size = ctf_type_size(ctfp, ctf_type_reference(ctfp, type));
656 	}
657 
658 	dt_cg_node(dnp->dn_child, dlp, drp);
659 	dnp->dn_reg = dnp->dn_child->dn_reg;
660 
661 	reg = dt_regset_alloc(drp);
662 	dt_cg_setx(dlp, reg, size);
663 
664 	instr = DIF_INSTR_FMT(op, dnp->dn_reg, reg, dnp->dn_reg);
665 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
666 	dt_regset_free(drp, reg);
667 
668 	/*
669 	 * If we are modifying a variable, generate an stv instruction from
670 	 * the variable specified by the identifier.  If we are storing to a
671 	 * memory address, generate code again for the left-hand side using
672 	 * DT_NF_REF to get the address, and then generate a store to it.
673 	 * In both paths, we store the value in dnp->dn_reg (the new value).
674 	 */
675 	if (dnp->dn_child->dn_kind == DT_NODE_VAR) {
676 		dt_ident_t *idp = dt_ident_resolve(dnp->dn_child->dn_ident);
677 
678 		idp->di_flags |= DT_IDFLG_DIFW;
679 		instr = DIF_INSTR_STV(dt_cg_stvar(idp),
680 		    idp->di_id, dnp->dn_reg);
681 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
682 	} else {
683 		uint_t rbit = dnp->dn_child->dn_flags & DT_NF_REF;
684 
685 		assert(dnp->dn_child->dn_flags & DT_NF_WRITABLE);
686 		assert(dnp->dn_child->dn_flags & DT_NF_LVALUE);
687 
688 		dnp->dn_child->dn_flags |= DT_NF_REF; /* force pass-by-ref */
689 		dt_cg_node(dnp->dn_child, dlp, drp);
690 
691 		dt_cg_store(dnp, dlp, drp, dnp->dn_child);
692 		dt_regset_free(drp, dnp->dn_child->dn_reg);
693 
694 		dnp->dn_left->dn_flags &= ~DT_NF_REF;
695 		dnp->dn_left->dn_flags |= rbit;
696 	}
697 }
698 
699 static void
700 dt_cg_postarith_op(dt_node_t *dnp, dt_irlist_t *dlp,
701     dt_regset_t *drp, uint_t op)
702 {
703 	ctf_file_t *ctfp = dnp->dn_ctfp;
704 	dif_instr_t instr;
705 	ctf_id_t type;
706 	ssize_t size = 1;
707 	int nreg;
708 
709 	if (dt_node_is_pointer(dnp)) {
710 		type = ctf_type_resolve(ctfp, dnp->dn_type);
711 		assert(ctf_type_kind(ctfp, type) == CTF_K_POINTER);
712 		size = ctf_type_size(ctfp, ctf_type_reference(ctfp, type));
713 	}
714 
715 	dt_cg_node(dnp->dn_child, dlp, drp);
716 	dnp->dn_reg = dnp->dn_child->dn_reg;
717 
718 	nreg = dt_regset_alloc(drp);
719 	dt_cg_setx(dlp, nreg, size);
720 	instr = DIF_INSTR_FMT(op, dnp->dn_reg, nreg, nreg);
721 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
722 
723 	/*
724 	 * If we are modifying a variable, generate an stv instruction from
725 	 * the variable specified by the identifier.  If we are storing to a
726 	 * memory address, generate code again for the left-hand side using
727 	 * DT_NF_REF to get the address, and then generate a store to it.
728 	 * In both paths, we store the value from 'nreg' (the new value).
729 	 */
730 	if (dnp->dn_child->dn_kind == DT_NODE_VAR) {
731 		dt_ident_t *idp = dt_ident_resolve(dnp->dn_child->dn_ident);
732 
733 		idp->di_flags |= DT_IDFLG_DIFW;
734 		instr = DIF_INSTR_STV(dt_cg_stvar(idp), idp->di_id, nreg);
735 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
736 	} else {
737 		uint_t rbit = dnp->dn_child->dn_flags & DT_NF_REF;
738 		int oreg = dnp->dn_reg;
739 
740 		assert(dnp->dn_child->dn_flags & DT_NF_WRITABLE);
741 		assert(dnp->dn_child->dn_flags & DT_NF_LVALUE);
742 
743 		dnp->dn_child->dn_flags |= DT_NF_REF; /* force pass-by-ref */
744 		dt_cg_node(dnp->dn_child, dlp, drp);
745 
746 		dnp->dn_reg = nreg;
747 		dt_cg_store(dnp, dlp, drp, dnp->dn_child);
748 		dnp->dn_reg = oreg;
749 
750 		dt_regset_free(drp, dnp->dn_child->dn_reg);
751 		dnp->dn_left->dn_flags &= ~DT_NF_REF;
752 		dnp->dn_left->dn_flags |= rbit;
753 	}
754 
755 	dt_regset_free(drp, nreg);
756 }
757 
758 /*
759  * Determine if we should perform signed or unsigned comparison for an OP2.
760  * If both operands are of arithmetic type, perform the usual arithmetic
761  * conversions to determine the common real type for comparison [ISOC 6.5.8.3].
762  */
763 static int
764 dt_cg_compare_signed(dt_node_t *dnp)
765 {
766 	dt_node_t dn;
767 
768 	if (dt_node_is_string(dnp->dn_left) ||
769 	    dt_node_is_string(dnp->dn_right))
770 		return (1); /* strings always compare signed */
771 	else if (!dt_node_is_arith(dnp->dn_left) ||
772 	    !dt_node_is_arith(dnp->dn_right))
773 		return (0); /* non-arithmetic types always compare unsigned */
774 
775 	bzero(&dn, sizeof (dn));
776 	dt_node_promote(dnp->dn_left, dnp->dn_right, &dn);
777 	return (dn.dn_flags & DT_NF_SIGNED);
778 }
779 
780 static void
781 dt_cg_compare_op(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp, uint_t op)
782 {
783 	uint_t lbl_true = dt_irlist_label(dlp);
784 	uint_t lbl_post = dt_irlist_label(dlp);
785 
786 	dif_instr_t instr;
787 	uint_t opc;
788 
789 	dt_cg_node(dnp->dn_left, dlp, drp);
790 	dt_cg_node(dnp->dn_right, dlp, drp);
791 
792 	if (dt_node_is_string(dnp->dn_left) || dt_node_is_string(dnp->dn_right))
793 		opc = DIF_OP_SCMP;
794 	else
795 		opc = DIF_OP_CMP;
796 
797 	instr = DIF_INSTR_CMP(opc, dnp->dn_left->dn_reg, dnp->dn_right->dn_reg);
798 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
799 	dt_regset_free(drp, dnp->dn_right->dn_reg);
800 	dnp->dn_reg = dnp->dn_left->dn_reg;
801 
802 	instr = DIF_INSTR_BRANCH(op, lbl_true);
803 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
804 
805 	instr = DIF_INSTR_MOV(DIF_REG_R0, dnp->dn_reg);
806 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
807 
808 	instr = DIF_INSTR_BRANCH(DIF_OP_BA, lbl_post);
809 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
810 
811 	dt_cg_xsetx(dlp, NULL, lbl_true, dnp->dn_reg, 1);
812 	dt_irlist_append(dlp, dt_cg_node_alloc(lbl_post, DIF_INSTR_NOP));
813 }
814 
815 /*
816  * Code generation for the ternary op requires some trickery with the assembler
817  * in order to conserve registers.  We generate code for dn_expr and dn_left
818  * and free their registers so they do not have be consumed across codegen for
819  * dn_right.  We insert a dummy MOV at the end of dn_left into the destination
820  * register, which is not yet known because we haven't done dn_right yet, and
821  * save the pointer to this instruction node.  We then generate code for
822  * dn_right and use its register as our output.  Finally, we reach back and
823  * patch the instruction for dn_left to move its output into this register.
824  */
825 static void
826 dt_cg_ternary_op(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
827 {
828 	uint_t lbl_false = dt_irlist_label(dlp);
829 	uint_t lbl_post = dt_irlist_label(dlp);
830 
831 	dif_instr_t instr;
832 	dt_irnode_t *dip;
833 
834 	dt_cg_node(dnp->dn_expr, dlp, drp);
835 	instr = DIF_INSTR_TST(dnp->dn_expr->dn_reg);
836 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
837 	dt_regset_free(drp, dnp->dn_expr->dn_reg);
838 
839 	instr = DIF_INSTR_BRANCH(DIF_OP_BE, lbl_false);
840 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
841 
842 	dt_cg_node(dnp->dn_left, dlp, drp);
843 	instr = DIF_INSTR_MOV(dnp->dn_left->dn_reg, DIF_REG_R0);
844 	dip = dt_cg_node_alloc(DT_LBL_NONE, instr); /* save dip for below */
845 	dt_irlist_append(dlp, dip);
846 	dt_regset_free(drp, dnp->dn_left->dn_reg);
847 
848 	instr = DIF_INSTR_BRANCH(DIF_OP_BA, lbl_post);
849 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
850 
851 	dt_irlist_append(dlp, dt_cg_node_alloc(lbl_false, DIF_INSTR_NOP));
852 	dt_cg_node(dnp->dn_right, dlp, drp);
853 	dnp->dn_reg = dnp->dn_right->dn_reg;
854 
855 	/*
856 	 * Now that dn_reg is assigned, reach back and patch the correct MOV
857 	 * instruction into the tail of dn_left.  We know dn_reg was unused
858 	 * at that point because otherwise dn_right couldn't have allocated it.
859 	 */
860 	dip->di_instr = DIF_INSTR_MOV(dnp->dn_left->dn_reg, dnp->dn_reg);
861 	dt_irlist_append(dlp, dt_cg_node_alloc(lbl_post, DIF_INSTR_NOP));
862 }
863 
864 static void
865 dt_cg_logical_and(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
866 {
867 	uint_t lbl_false = dt_irlist_label(dlp);
868 	uint_t lbl_post = dt_irlist_label(dlp);
869 
870 	dif_instr_t instr;
871 
872 	dt_cg_node(dnp->dn_left, dlp, drp);
873 	instr = DIF_INSTR_TST(dnp->dn_left->dn_reg);
874 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
875 	dt_regset_free(drp, dnp->dn_left->dn_reg);
876 
877 	instr = DIF_INSTR_BRANCH(DIF_OP_BE, lbl_false);
878 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
879 
880 	dt_cg_node(dnp->dn_right, dlp, drp);
881 	instr = DIF_INSTR_TST(dnp->dn_right->dn_reg);
882 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
883 	dnp->dn_reg = dnp->dn_right->dn_reg;
884 
885 	instr = DIF_INSTR_BRANCH(DIF_OP_BE, lbl_false);
886 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
887 
888 	dt_cg_setx(dlp, dnp->dn_reg, 1);
889 
890 	instr = DIF_INSTR_BRANCH(DIF_OP_BA, lbl_post);
891 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
892 
893 	instr = DIF_INSTR_MOV(DIF_REG_R0, dnp->dn_reg);
894 	dt_irlist_append(dlp, dt_cg_node_alloc(lbl_false, instr));
895 
896 	dt_irlist_append(dlp, dt_cg_node_alloc(lbl_post, DIF_INSTR_NOP));
897 }
898 
899 static void
900 dt_cg_logical_xor(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
901 {
902 	uint_t lbl_next = dt_irlist_label(dlp);
903 	uint_t lbl_tail = dt_irlist_label(dlp);
904 
905 	dif_instr_t instr;
906 
907 	dt_cg_node(dnp->dn_left, dlp, drp);
908 	instr = DIF_INSTR_TST(dnp->dn_left->dn_reg);
909 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
910 
911 	instr = DIF_INSTR_BRANCH(DIF_OP_BE, lbl_next);
912 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
913 	dt_cg_setx(dlp, dnp->dn_left->dn_reg, 1);
914 
915 	dt_irlist_append(dlp, dt_cg_node_alloc(lbl_next, DIF_INSTR_NOP));
916 	dt_cg_node(dnp->dn_right, dlp, drp);
917 
918 	instr = DIF_INSTR_TST(dnp->dn_right->dn_reg);
919 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
920 
921 	instr = DIF_INSTR_BRANCH(DIF_OP_BE, lbl_tail);
922 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
923 	dt_cg_setx(dlp, dnp->dn_right->dn_reg, 1);
924 
925 	instr = DIF_INSTR_FMT(DIF_OP_XOR, dnp->dn_left->dn_reg,
926 	    dnp->dn_right->dn_reg, dnp->dn_left->dn_reg);
927 
928 	dt_irlist_append(dlp, dt_cg_node_alloc(lbl_tail, instr));
929 
930 	dt_regset_free(drp, dnp->dn_right->dn_reg);
931 	dnp->dn_reg = dnp->dn_left->dn_reg;
932 }
933 
934 static void
935 dt_cg_logical_or(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
936 {
937 	uint_t lbl_true = dt_irlist_label(dlp);
938 	uint_t lbl_false = dt_irlist_label(dlp);
939 	uint_t lbl_post = dt_irlist_label(dlp);
940 
941 	dif_instr_t instr;
942 
943 	dt_cg_node(dnp->dn_left, dlp, drp);
944 	instr = DIF_INSTR_TST(dnp->dn_left->dn_reg);
945 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
946 	dt_regset_free(drp, dnp->dn_left->dn_reg);
947 
948 	instr = DIF_INSTR_BRANCH(DIF_OP_BNE, lbl_true);
949 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
950 
951 	dt_cg_node(dnp->dn_right, dlp, drp);
952 	instr = DIF_INSTR_TST(dnp->dn_right->dn_reg);
953 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
954 	dnp->dn_reg = dnp->dn_right->dn_reg;
955 
956 	instr = DIF_INSTR_BRANCH(DIF_OP_BE, lbl_false);
957 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
958 
959 	dt_cg_xsetx(dlp, NULL, lbl_true, dnp->dn_reg, 1);
960 
961 	instr = DIF_INSTR_BRANCH(DIF_OP_BA, lbl_post);
962 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
963 
964 	instr = DIF_INSTR_MOV(DIF_REG_R0, dnp->dn_reg);
965 	dt_irlist_append(dlp, dt_cg_node_alloc(lbl_false, instr));
966 
967 	dt_irlist_append(dlp, dt_cg_node_alloc(lbl_post, DIF_INSTR_NOP));
968 }
969 
970 static void
971 dt_cg_logical_neg(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
972 {
973 	uint_t lbl_zero = dt_irlist_label(dlp);
974 	uint_t lbl_post = dt_irlist_label(dlp);
975 
976 	dif_instr_t instr;
977 
978 	dt_cg_node(dnp->dn_child, dlp, drp);
979 	dnp->dn_reg = dnp->dn_child->dn_reg;
980 
981 	instr = DIF_INSTR_TST(dnp->dn_reg);
982 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
983 
984 	instr = DIF_INSTR_BRANCH(DIF_OP_BE, lbl_zero);
985 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
986 
987 	instr = DIF_INSTR_MOV(DIF_REG_R0, dnp->dn_reg);
988 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
989 
990 	instr = DIF_INSTR_BRANCH(DIF_OP_BA, lbl_post);
991 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
992 
993 	dt_cg_xsetx(dlp, NULL, lbl_zero, dnp->dn_reg, 1);
994 	dt_irlist_append(dlp, dt_cg_node_alloc(lbl_post, DIF_INSTR_NOP));
995 }
996 
997 static void
998 dt_cg_asgn_op(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
999 {
1000 	dif_instr_t instr;
1001 	dt_ident_t *idp;
1002 
1003 	/*
1004 	 * If we are performing a structure assignment of a translated type,
1005 	 * we must instantiate all members and create a snapshot of the object
1006 	 * in scratch space.  We allocs a chunk of memory, generate code for
1007 	 * each member, and then set dnp->dn_reg to the scratch object address.
1008 	 */
1009 	if ((idp = dt_node_resolve(dnp->dn_right, DT_IDENT_XLSOU)) != NULL) {
1010 		ctf_membinfo_t ctm;
1011 		dt_xlator_t *dxp = idp->di_data;
1012 		dt_node_t *mnp, dn, mn;
1013 		int r1, r2;
1014 
1015 		/*
1016 		 * Create two fake dt_node_t's representing operator "." and a
1017 		 * right-hand identifier child node.  These will be repeatedly
1018 		 * modified according to each instantiated member so that we
1019 		 * can pass them to dt_cg_store() and effect a member store.
1020 		 */
1021 		bzero(&dn, sizeof (dt_node_t));
1022 		dn.dn_kind = DT_NODE_OP2;
1023 		dn.dn_op = DT_TOK_DOT;
1024 		dn.dn_left = dnp;
1025 		dn.dn_right = &mn;
1026 
1027 		bzero(&mn, sizeof (dt_node_t));
1028 		mn.dn_kind = DT_NODE_IDENT;
1029 		mn.dn_op = DT_TOK_IDENT;
1030 
1031 		/*
1032 		 * Allocate a register for our scratch data pointer.  First we
1033 		 * set it to the size of our data structure, and then replace
1034 		 * it with the result of an allocs of the specified size.
1035 		 */
1036 		r1 = dt_regset_alloc(drp);
1037 		dt_cg_setx(dlp, r1,
1038 		    ctf_type_size(dxp->dx_dst_ctfp, dxp->dx_dst_base));
1039 
1040 		instr = DIF_INSTR_ALLOCS(r1, r1);
1041 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1042 
1043 		/*
1044 		 * When dt_cg_asgn_op() is called, we have already generated
1045 		 * code for dnp->dn_right, which is the translator input.  We
1046 		 * now associate this register with the translator's input
1047 		 * identifier so it can be referenced during our member loop.
1048 		 */
1049 		dxp->dx_ident->di_flags |= DT_IDFLG_CGREG;
1050 		dxp->dx_ident->di_id = dnp->dn_right->dn_reg;
1051 
1052 		for (mnp = dxp->dx_members; mnp != NULL; mnp = mnp->dn_list) {
1053 			/*
1054 			 * Generate code for the translator member expression,
1055 			 * and then cast the result to the member type.
1056 			 */
1057 			dt_cg_node(mnp->dn_membexpr, dlp, drp);
1058 			mnp->dn_reg = mnp->dn_membexpr->dn_reg;
1059 			dt_cg_typecast(mnp->dn_membexpr, mnp, dlp, drp);
1060 
1061 			/*
1062 			 * Ask CTF for the offset of the member so we can store
1063 			 * to the appropriate offset.  This call has already
1064 			 * been done once by the parser, so it should succeed.
1065 			 */
1066 			if (ctf_member_info(dxp->dx_dst_ctfp, dxp->dx_dst_base,
1067 			    mnp->dn_membname, &ctm) == CTF_ERR) {
1068 				yypcb->pcb_hdl->dt_ctferr =
1069 				    ctf_errno(dxp->dx_dst_ctfp);
1070 				longjmp(yypcb->pcb_jmpbuf, EDT_CTF);
1071 			}
1072 
1073 			/*
1074 			 * If the destination member is at offset 0, store the
1075 			 * result directly to r1 (the scratch buffer address).
1076 			 * Otherwise allocate another temporary for the offset
1077 			 * and add r1 to it before storing the result.
1078 			 */
1079 			if (ctm.ctm_offset != 0) {
1080 				r2 = dt_regset_alloc(drp);
1081 
1082 				/*
1083 				 * Add the member offset rounded down to the
1084 				 * nearest byte.  If the offset was not aligned
1085 				 * on a byte boundary, this member is a bit-
1086 				 * field and dt_cg_store() will handle masking.
1087 				 */
1088 				dt_cg_setx(dlp, r2, ctm.ctm_offset / NBBY);
1089 				instr = DIF_INSTR_FMT(DIF_OP_ADD, r1, r2, r2);
1090 				dt_irlist_append(dlp,
1091 				    dt_cg_node_alloc(DT_LBL_NONE, instr));
1092 
1093 				dt_node_type_propagate(mnp, &dn);
1094 				dn.dn_right->dn_string = mnp->dn_membname;
1095 				dn.dn_reg = r2;
1096 
1097 				dt_cg_store(mnp, dlp, drp, &dn);
1098 				dt_regset_free(drp, r2);
1099 
1100 			} else {
1101 				dt_node_type_propagate(mnp, &dn);
1102 				dn.dn_right->dn_string = mnp->dn_membname;
1103 				dn.dn_reg = r1;
1104 
1105 				dt_cg_store(mnp, dlp, drp, &dn);
1106 			}
1107 
1108 			dt_regset_free(drp, mnp->dn_reg);
1109 		}
1110 
1111 		dxp->dx_ident->di_flags &= ~DT_IDFLG_CGREG;
1112 		dxp->dx_ident->di_id = 0;
1113 
1114 		if (dnp->dn_right->dn_reg != -1)
1115 			dt_regset_free(drp, dnp->dn_right->dn_reg);
1116 
1117 		assert(dnp->dn_reg == dnp->dn_right->dn_reg);
1118 		dnp->dn_reg = r1;
1119 	}
1120 
1121 	/*
1122 	 * If we are storing to a memory address, generate code again for the
1123 	 * left-hand side using DT_NF_REF to get the address, and then generate
1124 	 * a store to it.
1125 	 *
1126 	 * Both here and the other variable-store paths, we assume dnp->dn_reg
1127 	 * already has the new value.
1128 	 */
1129 	if (dnp->dn_left->dn_kind != DT_NODE_VAR) {
1130 		uint_t rbit = dnp->dn_left->dn_flags & DT_NF_REF;
1131 
1132 		assert(dnp->dn_left->dn_flags & DT_NF_WRITABLE);
1133 		assert(dnp->dn_left->dn_flags & DT_NF_LVALUE);
1134 
1135 		dnp->dn_left->dn_flags |= DT_NF_REF; /* force pass-by-ref */
1136 
1137 		dt_cg_node(dnp->dn_left, dlp, drp);
1138 		dt_cg_store(dnp, dlp, drp, dnp->dn_left);
1139 		dt_regset_free(drp, dnp->dn_left->dn_reg);
1140 
1141 		dnp->dn_left->dn_flags &= ~DT_NF_REF;
1142 		dnp->dn_left->dn_flags |= rbit;
1143 		return;
1144 	}
1145 
1146 	idp = dt_ident_resolve(dnp->dn_left->dn_ident);
1147 	idp->di_flags |= DT_IDFLG_DIFW;
1148 
1149 	/*
1150 	 * Storing to an array variable is a special case.
1151 	 * Only 'uregs[]' supports this for the time being.
1152 	 */
1153 	if (idp->di_kind == DT_IDENT_ARRAY &&
1154 	    idp->di_id <= DIF_VAR_ARRAY_MAX) {
1155 		dt_node_t *idx = dnp->dn_left->dn_args;
1156 
1157 		dt_cg_node(idx, dlp, drp);
1158 		instr = DIF_INSTR_FMT(DIF_OP_STGA, idp->di_id, idx->dn_reg,
1159 		    dnp->dn_reg);
1160 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1161 		dt_regset_free(drp, idx->dn_reg);
1162 		return;
1163 	}
1164 
1165 	if (idp->di_kind == DT_IDENT_ARRAY)
1166 		dt_cg_arglist(idp, dnp->dn_left->dn_args, dlp, drp);
1167 
1168 	instr = DIF_INSTR_STV(dt_cg_stvar(idp), idp->di_id, dnp->dn_reg);
1169 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1170 }
1171 
1172 static void
1173 dt_cg_assoc_op(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
1174 {
1175 	dif_instr_t instr;
1176 	uint_t op;
1177 
1178 	assert(dnp->dn_kind == DT_NODE_VAR);
1179 	assert(!(dnp->dn_ident->di_flags & DT_IDFLG_LOCAL));
1180 	assert(dnp->dn_args != NULL);
1181 
1182 	dt_cg_arglist(dnp->dn_ident, dnp->dn_args, dlp, drp);
1183 
1184 	dnp->dn_reg = dt_regset_alloc(drp);
1185 
1186 	if (dnp->dn_ident->di_flags & DT_IDFLG_TLS)
1187 		op = DIF_OP_LDTAA;
1188 	else
1189 		op = DIF_OP_LDGAA;
1190 
1191 	dnp->dn_ident->di_flags |= DT_IDFLG_DIFR;
1192 	instr = DIF_INSTR_LDV(op, dnp->dn_ident->di_id, dnp->dn_reg);
1193 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1194 
1195 	/*
1196 	 * If the associative array is a pass-by-reference type, then we are
1197 	 * loading its value as a pointer to either load or store through it.
1198 	 * The array element in question may not have been faulted in yet, in
1199 	 * which case DIF_OP_LD*AA will return zero.  We append an epilogue
1200 	 * of instructions similar to the following:
1201 	 *
1202 	 *	  ld?aa	 id, %r1	! base ld?aa instruction above
1203 	 *	  tst	 %r1		! start of epilogue
1204 	 *   +--- bne	 label
1205 	 *   |    setx	 size, %r1
1206 	 *   |    allocs %r1, %r1
1207 	 *   |    st?aa	 id, %r1
1208 	 *   |    ld?aa	 id, %r1
1209 	 *   v
1210 	 * label: < rest of code >
1211 	 *
1212 	 * The idea is that we allocs a zero-filled chunk of scratch space and
1213 	 * do a DIF_OP_ST*AA to fault in and initialize the array element, and
1214 	 * then reload it to get the faulted-in address of the new variable
1215 	 * storage.  This isn't cheap, but pass-by-ref associative array values
1216 	 * are (thus far) uncommon and the allocs cost only occurs once.  If
1217 	 * this path becomes important to DTrace users, we can improve things
1218 	 * by adding a new DIF opcode to fault in associative array elements.
1219 	 */
1220 	if (dnp->dn_flags & DT_NF_REF) {
1221 		uint_t stvop = op == DIF_OP_LDTAA ? DIF_OP_STTAA : DIF_OP_STGAA;
1222 		uint_t label = dt_irlist_label(dlp);
1223 
1224 		instr = DIF_INSTR_TST(dnp->dn_reg);
1225 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1226 
1227 		instr = DIF_INSTR_BRANCH(DIF_OP_BNE, label);
1228 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1229 
1230 		dt_cg_setx(dlp, dnp->dn_reg, dt_node_type_size(dnp));
1231 		instr = DIF_INSTR_ALLOCS(dnp->dn_reg, dnp->dn_reg);
1232 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1233 
1234 		dnp->dn_ident->di_flags |= DT_IDFLG_DIFW;
1235 		instr = DIF_INSTR_STV(stvop, dnp->dn_ident->di_id, dnp->dn_reg);
1236 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1237 
1238 		instr = DIF_INSTR_LDV(op, dnp->dn_ident->di_id, dnp->dn_reg);
1239 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1240 
1241 		dt_irlist_append(dlp, dt_cg_node_alloc(label, DIF_INSTR_NOP));
1242 	}
1243 }
1244 
1245 static void
1246 dt_cg_array_op(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
1247 {
1248 	dt_probe_t *prp = yypcb->pcb_probe;
1249 	uintmax_t saved = dnp->dn_args->dn_value;
1250 	dt_ident_t *idp = dnp->dn_ident;
1251 
1252 	dif_instr_t instr;
1253 	uint_t op;
1254 	size_t size;
1255 	int reg, n;
1256 
1257 	assert(dnp->dn_kind == DT_NODE_VAR);
1258 	assert(!(idp->di_flags & DT_IDFLG_LOCAL));
1259 
1260 	assert(dnp->dn_args->dn_kind == DT_NODE_INT);
1261 	assert(dnp->dn_args->dn_list == NULL);
1262 
1263 	/*
1264 	 * If this is a reference in the args[] array, temporarily modify the
1265 	 * array index according to the static argument mapping (if any),
1266 	 * unless the argument reference is provided by a dynamic translator.
1267 	 * If we're using a dynamic translator for args[], then just set dn_reg
1268 	 * to an invalid reg and return: DIF_OP_XLARG will fetch the arg later.
1269 	 */
1270 	if (idp->di_id == DIF_VAR_ARGS) {
1271 		if ((idp->di_kind == DT_IDENT_XLPTR ||
1272 		    idp->di_kind == DT_IDENT_XLSOU) &&
1273 		    dt_xlator_dynamic(idp->di_data)) {
1274 			dnp->dn_reg = -1;
1275 			return;
1276 		}
1277 		dnp->dn_args->dn_value = prp->pr_mapping[saved];
1278 	}
1279 
1280 	dt_cg_node(dnp->dn_args, dlp, drp);
1281 	dnp->dn_args->dn_value = saved;
1282 
1283 	dnp->dn_reg = dnp->dn_args->dn_reg;
1284 
1285 	if (idp->di_flags & DT_IDFLG_TLS)
1286 		op = DIF_OP_LDTA;
1287 	else
1288 		op = DIF_OP_LDGA;
1289 
1290 	idp->di_flags |= DT_IDFLG_DIFR;
1291 
1292 	instr = DIF_INSTR_LDA(op, idp->di_id,
1293 	    dnp->dn_args->dn_reg, dnp->dn_reg);
1294 
1295 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1296 
1297 	/*
1298 	 * If this is a reference to the args[] array, we need to take the
1299 	 * additional step of explicitly eliminating any bits larger than the
1300 	 * type size: the DIF interpreter in the kernel will always give us
1301 	 * the raw (64-bit) argument value, and any bits larger than the type
1302 	 * size may be junk.  As a practical matter, this arises only on 64-bit
1303 	 * architectures and only when the argument index is larger than the
1304 	 * number of arguments passed directly to DTrace: if a 8-, 16- or
1305 	 * 32-bit argument must be retrieved from the stack, it is possible
1306 	 * (and it some cases, likely) that the upper bits will be garbage.
1307 	 */
1308 	if (idp->di_id != DIF_VAR_ARGS || !dt_node_is_scalar(dnp))
1309 		return;
1310 
1311 	if ((size = dt_node_type_size(dnp)) == sizeof (uint64_t))
1312 		return;
1313 
1314 	reg = dt_regset_alloc(drp);
1315 	assert(size < sizeof (uint64_t));
1316 	n = sizeof (uint64_t) * NBBY - size * NBBY;
1317 
1318 	dt_cg_setx(dlp, reg, n);
1319 
1320 	instr = DIF_INSTR_FMT(DIF_OP_SLL, dnp->dn_reg, reg, dnp->dn_reg);
1321 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1322 
1323 	instr = DIF_INSTR_FMT((dnp->dn_flags & DT_NF_SIGNED) ?
1324 	    DIF_OP_SRA : DIF_OP_SRL, dnp->dn_reg, reg, dnp->dn_reg);
1325 
1326 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1327 	dt_regset_free(drp, reg);
1328 }
1329 
1330 /*
1331  * Generate code for an inlined variable reference.  Inlines can be used to
1332  * define either scalar or associative array substitutions.  For scalars, we
1333  * simply generate code for the parse tree saved in the identifier's din_root,
1334  * and then cast the resulting expression to the inline's declaration type.
1335  * For arrays, we take the input parameter subtrees from dnp->dn_args and
1336  * temporarily store them in the din_root of each din_argv[i] identifier,
1337  * which are themselves inlines and were set up for us by the parser.  The
1338  * result is that any reference to the inlined parameter inside the top-level
1339  * din_root will turn into a recursive call to dt_cg_inline() for a scalar
1340  * inline whose din_root will refer to the subtree pointed to by the argument.
1341  */
1342 static void
1343 dt_cg_inline(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
1344 {
1345 	dt_ident_t *idp = dnp->dn_ident;
1346 	dt_idnode_t *inp = idp->di_iarg;
1347 
1348 	dt_idnode_t *pinp;
1349 	dt_node_t *pnp;
1350 	int i;
1351 
1352 	assert(idp->di_flags & DT_IDFLG_INLINE);
1353 	assert(idp->di_ops == &dt_idops_inline);
1354 
1355 	if (idp->di_kind == DT_IDENT_ARRAY) {
1356 		for (i = 0, pnp = dnp->dn_args;
1357 		    pnp != NULL; pnp = pnp->dn_list, i++) {
1358 			if (inp->din_argv[i] != NULL) {
1359 				pinp = inp->din_argv[i]->di_iarg;
1360 				pinp->din_root = pnp;
1361 			}
1362 		}
1363 	}
1364 
1365 	dt_cg_node(inp->din_root, dlp, drp);
1366 	dnp->dn_reg = inp->din_root->dn_reg;
1367 	dt_cg_typecast(inp->din_root, dnp, dlp, drp);
1368 
1369 	if (idp->di_kind == DT_IDENT_ARRAY) {
1370 		for (i = 0; i < inp->din_argc; i++) {
1371 			pinp = inp->din_argv[i]->di_iarg;
1372 			pinp->din_root = NULL;
1373 		}
1374 	}
1375 }
1376 
1377 typedef struct dt_xlmemb {
1378 	dt_ident_t *dtxl_idp;		/* translated ident */
1379 	dt_irlist_t *dtxl_dlp;		/* instruction list */
1380 	dt_regset_t *dtxl_drp;		/* register set */
1381 	int dtxl_sreg;			/* location of the translation input */
1382 	int dtxl_dreg;			/* location of our allocated buffer */
1383 } dt_xlmemb_t;
1384 
1385 /*ARGSUSED*/
1386 static int
1387 dt_cg_xlate_member(const char *name, ctf_id_t type, ulong_t off, void *arg)
1388 {
1389 	dt_xlmemb_t *dx = arg;
1390 	dt_ident_t *idp = dx->dtxl_idp;
1391 	dt_irlist_t *dlp = dx->dtxl_dlp;
1392 	dt_regset_t *drp = dx->dtxl_drp;
1393 
1394 	dt_node_t *mnp;
1395 	dt_xlator_t *dxp;
1396 
1397 	int reg, treg;
1398 	uint32_t instr;
1399 	size_t size;
1400 
1401 	/* Generate code for the translation. */
1402 	dxp = idp->di_data;
1403 	mnp = dt_xlator_member(dxp, name);
1404 
1405 	/* If there's no translator for the given member, skip it. */
1406 	if (mnp == NULL)
1407 		return (0);
1408 
1409 	dxp->dx_ident->di_flags |= DT_IDFLG_CGREG;
1410 	dxp->dx_ident->di_id = dx->dtxl_sreg;
1411 
1412 	dt_cg_node(mnp->dn_membexpr, dlp, drp);
1413 
1414 	dxp->dx_ident->di_flags &= ~DT_IDFLG_CGREG;
1415 	dxp->dx_ident->di_id = 0;
1416 
1417 	treg = mnp->dn_membexpr->dn_reg;
1418 
1419 	/* Compute the offset into our buffer and store the result there. */
1420 	reg = dt_regset_alloc(drp);
1421 
1422 	dt_cg_setx(dlp, reg, off / NBBY);
1423 	instr = DIF_INSTR_FMT(DIF_OP_ADD, dx->dtxl_dreg, reg, reg);
1424 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1425 
1426 	size = ctf_type_size(mnp->dn_membexpr->dn_ctfp,
1427 	    mnp->dn_membexpr->dn_type);
1428 	if (dt_node_is_scalar(mnp->dn_membexpr)) {
1429 		/*
1430 		 * Copying scalars is simple.
1431 		 */
1432 		switch (size) {
1433 		case 1:
1434 			instr = DIF_INSTR_STORE(DIF_OP_STB, treg, reg);
1435 			break;
1436 		case 2:
1437 			instr = DIF_INSTR_STORE(DIF_OP_STH, treg, reg);
1438 			break;
1439 		case 4:
1440 			instr = DIF_INSTR_STORE(DIF_OP_STW, treg, reg);
1441 			break;
1442 		case 8:
1443 			instr = DIF_INSTR_STORE(DIF_OP_STX, treg, reg);
1444 			break;
1445 		default:
1446 			xyerror(D_UNKNOWN, "internal error -- unexpected "
1447 			    "size: %lu\n", (ulong_t)size);
1448 		}
1449 
1450 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1451 
1452 	} else if (dt_node_is_string(mnp->dn_membexpr)) {
1453 		int szreg;
1454 
1455 		/*
1456 		 * Use the copys instruction for strings.
1457 		 */
1458 		szreg = dt_regset_alloc(drp);
1459 		dt_cg_setx(dlp, szreg, size);
1460 		instr = DIF_INSTR_COPYS(treg, szreg, reg);
1461 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1462 		dt_regset_free(drp, szreg);
1463 	} else {
1464 		int szreg;
1465 
1466 		/*
1467 		 * If it's anything else then we'll just bcopy it.
1468 		 */
1469 		szreg = dt_regset_alloc(drp);
1470 		dt_cg_setx(dlp, szreg, size);
1471 		dt_irlist_append(dlp,
1472 		    dt_cg_node_alloc(DT_LBL_NONE, DIF_INSTR_FLUSHTS));
1473 		instr = DIF_INSTR_PUSHTS(DIF_OP_PUSHTV, DIF_TYPE_CTF,
1474 		    DIF_REG_R0, treg);
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, reg);
1478 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1479 		instr = DIF_INSTR_PUSHTS(DIF_OP_PUSHTV, DIF_TYPE_CTF,
1480 		    DIF_REG_R0, szreg);
1481 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1482 		instr = DIF_INSTR_CALL(DIF_SUBR_BCOPY, szreg);
1483 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1484 		dt_regset_free(drp, szreg);
1485 	}
1486 
1487 	dt_regset_free(drp, reg);
1488 	dt_regset_free(drp, treg);
1489 
1490 	return (0);
1491 }
1492 
1493 /*
1494  * If we're expanding a translated type, we create an appropriately sized
1495  * buffer with alloca() and then translate each member into it.
1496  */
1497 static int
1498 dt_cg_xlate_expand(dt_node_t *dnp, dt_ident_t *idp, dt_irlist_t *dlp,
1499     dt_regset_t *drp)
1500 {
1501 	dt_xlmemb_t dlm;
1502 	uint32_t instr;
1503 	int dreg;
1504 	size_t size;
1505 
1506 	dreg = dt_regset_alloc(drp);
1507 	size = ctf_type_size(dnp->dn_ident->di_ctfp, dnp->dn_ident->di_type);
1508 
1509 	/* Call alloca() to create the buffer. */
1510 	dt_cg_setx(dlp, dreg, size);
1511 
1512 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, DIF_INSTR_FLUSHTS));
1513 
1514 	instr = DIF_INSTR_PUSHTS(DIF_OP_PUSHTV, DIF_TYPE_CTF, DIF_REG_R0, dreg);
1515 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1516 
1517 	instr = DIF_INSTR_CALL(DIF_SUBR_ALLOCA, dreg);
1518 	dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1519 
1520 	/* Generate the translation for each member. */
1521 	dlm.dtxl_idp = idp;
1522 	dlm.dtxl_dlp = dlp;
1523 	dlm.dtxl_drp = drp;
1524 	dlm.dtxl_sreg = dnp->dn_reg;
1525 	dlm.dtxl_dreg = dreg;
1526 	(void) ctf_member_iter(dnp->dn_ident->di_ctfp,
1527 	    dnp->dn_ident->di_type, dt_cg_xlate_member,
1528 	    &dlm);
1529 
1530 	return (dreg);
1531 }
1532 
1533 static void
1534 dt_cg_node(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
1535 {
1536 	ctf_file_t *ctfp = dnp->dn_ctfp;
1537 	ctf_file_t *octfp;
1538 	ctf_membinfo_t m;
1539 	ctf_id_t type;
1540 
1541 	dif_instr_t instr;
1542 	dt_ident_t *idp;
1543 	ssize_t stroff;
1544 	uint_t op;
1545 
1546 	switch (dnp->dn_op) {
1547 	case DT_TOK_COMMA:
1548 		dt_cg_node(dnp->dn_left, dlp, drp);
1549 		dt_regset_free(drp, dnp->dn_left->dn_reg);
1550 		dt_cg_node(dnp->dn_right, dlp, drp);
1551 		dnp->dn_reg = dnp->dn_right->dn_reg;
1552 		break;
1553 
1554 	case DT_TOK_ASGN:
1555 		dt_cg_node(dnp->dn_right, dlp, drp);
1556 		dnp->dn_reg = dnp->dn_right->dn_reg;
1557 		dt_cg_asgn_op(dnp, dlp, drp);
1558 		break;
1559 
1560 	case DT_TOK_ADD_EQ:
1561 		dt_cg_arithmetic_op(dnp, dlp, drp, DIF_OP_ADD);
1562 		dt_cg_asgn_op(dnp, dlp, drp);
1563 		break;
1564 
1565 	case DT_TOK_SUB_EQ:
1566 		dt_cg_arithmetic_op(dnp, dlp, drp, DIF_OP_SUB);
1567 		dt_cg_asgn_op(dnp, dlp, drp);
1568 		break;
1569 
1570 	case DT_TOK_MUL_EQ:
1571 		dt_cg_arithmetic_op(dnp, dlp, drp, DIF_OP_MUL);
1572 		dt_cg_asgn_op(dnp, dlp, drp);
1573 		break;
1574 
1575 	case DT_TOK_DIV_EQ:
1576 		dt_cg_arithmetic_op(dnp, dlp, drp,
1577 		    (dnp->dn_flags & DT_NF_SIGNED) ? DIF_OP_SDIV : DIF_OP_UDIV);
1578 		dt_cg_asgn_op(dnp, dlp, drp);
1579 		break;
1580 
1581 	case DT_TOK_MOD_EQ:
1582 		dt_cg_arithmetic_op(dnp, dlp, drp,
1583 		    (dnp->dn_flags & DT_NF_SIGNED) ? DIF_OP_SREM : DIF_OP_UREM);
1584 		dt_cg_asgn_op(dnp, dlp, drp);
1585 		break;
1586 
1587 	case DT_TOK_AND_EQ:
1588 		dt_cg_arithmetic_op(dnp, dlp, drp, DIF_OP_AND);
1589 		dt_cg_asgn_op(dnp, dlp, drp);
1590 		break;
1591 
1592 	case DT_TOK_XOR_EQ:
1593 		dt_cg_arithmetic_op(dnp, dlp, drp, DIF_OP_XOR);
1594 		dt_cg_asgn_op(dnp, dlp, drp);
1595 		break;
1596 
1597 	case DT_TOK_OR_EQ:
1598 		dt_cg_arithmetic_op(dnp, dlp, drp, DIF_OP_OR);
1599 		dt_cg_asgn_op(dnp, dlp, drp);
1600 		break;
1601 
1602 	case DT_TOK_LSH_EQ:
1603 		dt_cg_arithmetic_op(dnp, dlp, drp, DIF_OP_SLL);
1604 		dt_cg_asgn_op(dnp, dlp, drp);
1605 		break;
1606 
1607 	case DT_TOK_RSH_EQ:
1608 		dt_cg_arithmetic_op(dnp, dlp, drp,
1609 		    (dnp->dn_flags & DT_NF_SIGNED) ? DIF_OP_SRA : DIF_OP_SRL);
1610 		dt_cg_asgn_op(dnp, dlp, drp);
1611 		break;
1612 
1613 	case DT_TOK_QUESTION:
1614 		dt_cg_ternary_op(dnp, dlp, drp);
1615 		break;
1616 
1617 	case DT_TOK_LOR:
1618 		dt_cg_logical_or(dnp, dlp, drp);
1619 		break;
1620 
1621 	case DT_TOK_LXOR:
1622 		dt_cg_logical_xor(dnp, dlp, drp);
1623 		break;
1624 
1625 	case DT_TOK_LAND:
1626 		dt_cg_logical_and(dnp, dlp, drp);
1627 		break;
1628 
1629 	case DT_TOK_BOR:
1630 		dt_cg_arithmetic_op(dnp, dlp, drp, DIF_OP_OR);
1631 		break;
1632 
1633 	case DT_TOK_XOR:
1634 		dt_cg_arithmetic_op(dnp, dlp, drp, DIF_OP_XOR);
1635 		break;
1636 
1637 	case DT_TOK_BAND:
1638 		dt_cg_arithmetic_op(dnp, dlp, drp, DIF_OP_AND);
1639 		break;
1640 
1641 	case DT_TOK_EQU:
1642 		dt_cg_compare_op(dnp, dlp, drp, DIF_OP_BE);
1643 		break;
1644 
1645 	case DT_TOK_NEQ:
1646 		dt_cg_compare_op(dnp, dlp, drp, DIF_OP_BNE);
1647 		break;
1648 
1649 	case DT_TOK_LT:
1650 		dt_cg_compare_op(dnp, dlp, drp,
1651 		    dt_cg_compare_signed(dnp) ? DIF_OP_BL : DIF_OP_BLU);
1652 		break;
1653 
1654 	case DT_TOK_LE:
1655 		dt_cg_compare_op(dnp, dlp, drp,
1656 		    dt_cg_compare_signed(dnp) ? DIF_OP_BLE : DIF_OP_BLEU);
1657 		break;
1658 
1659 	case DT_TOK_GT:
1660 		dt_cg_compare_op(dnp, dlp, drp,
1661 		    dt_cg_compare_signed(dnp) ? DIF_OP_BG : DIF_OP_BGU);
1662 		break;
1663 
1664 	case DT_TOK_GE:
1665 		dt_cg_compare_op(dnp, dlp, drp,
1666 		    dt_cg_compare_signed(dnp) ? DIF_OP_BGE : DIF_OP_BGEU);
1667 		break;
1668 
1669 	case DT_TOK_LSH:
1670 		dt_cg_arithmetic_op(dnp, dlp, drp, DIF_OP_SLL);
1671 		break;
1672 
1673 	case DT_TOK_RSH:
1674 		dt_cg_arithmetic_op(dnp, dlp, drp,
1675 		    (dnp->dn_flags & DT_NF_SIGNED) ? DIF_OP_SRA : DIF_OP_SRL);
1676 		break;
1677 
1678 	case DT_TOK_ADD:
1679 		dt_cg_arithmetic_op(dnp, dlp, drp, DIF_OP_ADD);
1680 		break;
1681 
1682 	case DT_TOK_SUB:
1683 		dt_cg_arithmetic_op(dnp, dlp, drp, DIF_OP_SUB);
1684 		break;
1685 
1686 	case DT_TOK_MUL:
1687 		dt_cg_arithmetic_op(dnp, dlp, drp, DIF_OP_MUL);
1688 		break;
1689 
1690 	case DT_TOK_DIV:
1691 		dt_cg_arithmetic_op(dnp, dlp, drp,
1692 		    (dnp->dn_flags & DT_NF_SIGNED) ? DIF_OP_SDIV : DIF_OP_UDIV);
1693 		break;
1694 
1695 	case DT_TOK_MOD:
1696 		dt_cg_arithmetic_op(dnp, dlp, drp,
1697 		    (dnp->dn_flags & DT_NF_SIGNED) ? DIF_OP_SREM : DIF_OP_UREM);
1698 		break;
1699 
1700 	case DT_TOK_LNEG:
1701 		dt_cg_logical_neg(dnp, dlp, drp);
1702 		break;
1703 
1704 	case DT_TOK_BNEG:
1705 		dt_cg_node(dnp->dn_child, dlp, drp);
1706 		dnp->dn_reg = dnp->dn_child->dn_reg;
1707 		instr = DIF_INSTR_NOT(dnp->dn_reg, dnp->dn_reg);
1708 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1709 		break;
1710 
1711 	case DT_TOK_PREINC:
1712 		dt_cg_prearith_op(dnp, dlp, drp, DIF_OP_ADD);
1713 		break;
1714 
1715 	case DT_TOK_POSTINC:
1716 		dt_cg_postarith_op(dnp, dlp, drp, DIF_OP_ADD);
1717 		break;
1718 
1719 	case DT_TOK_PREDEC:
1720 		dt_cg_prearith_op(dnp, dlp, drp, DIF_OP_SUB);
1721 		break;
1722 
1723 	case DT_TOK_POSTDEC:
1724 		dt_cg_postarith_op(dnp, dlp, drp, DIF_OP_SUB);
1725 		break;
1726 
1727 	case DT_TOK_IPOS:
1728 		dt_cg_node(dnp->dn_child, dlp, drp);
1729 		dnp->dn_reg = dnp->dn_child->dn_reg;
1730 		break;
1731 
1732 	case DT_TOK_INEG:
1733 		dt_cg_node(dnp->dn_child, dlp, drp);
1734 		dnp->dn_reg = dnp->dn_child->dn_reg;
1735 
1736 		instr = DIF_INSTR_FMT(DIF_OP_SUB, DIF_REG_R0,
1737 		    dnp->dn_reg, dnp->dn_reg);
1738 
1739 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1740 		break;
1741 
1742 	case DT_TOK_DEREF:
1743 		dt_cg_node(dnp->dn_child, dlp, drp);
1744 		dnp->dn_reg = dnp->dn_child->dn_reg;
1745 
1746 		if (dt_node_is_dynamic(dnp->dn_child)) {
1747 			int reg;
1748 			idp = dt_node_resolve(dnp->dn_child, DT_IDENT_XLPTR);
1749 			assert(idp != NULL);
1750 			reg = dt_cg_xlate_expand(dnp, idp, dlp, drp);
1751 
1752 			dt_regset_free(drp, dnp->dn_child->dn_reg);
1753 			dnp->dn_reg = reg;
1754 
1755 		} else if (!(dnp->dn_flags & DT_NF_REF)) {
1756 			uint_t ubit = dnp->dn_flags & DT_NF_USERLAND;
1757 
1758 			/*
1759 			 * Save and restore DT_NF_USERLAND across dt_cg_load():
1760 			 * we need the sign bit from dnp and the user bit from
1761 			 * dnp->dn_child in order to get the proper opcode.
1762 			 */
1763 			dnp->dn_flags |=
1764 			    (dnp->dn_child->dn_flags & DT_NF_USERLAND);
1765 
1766 			instr = DIF_INSTR_LOAD(dt_cg_load(dnp, ctfp,
1767 			    dnp->dn_type), dnp->dn_reg, dnp->dn_reg);
1768 
1769 			dnp->dn_flags &= ~DT_NF_USERLAND;
1770 			dnp->dn_flags |= ubit;
1771 
1772 			dt_irlist_append(dlp,
1773 			    dt_cg_node_alloc(DT_LBL_NONE, instr));
1774 		}
1775 		break;
1776 
1777 	case DT_TOK_ADDROF: {
1778 		uint_t rbit = dnp->dn_child->dn_flags & DT_NF_REF;
1779 
1780 		dnp->dn_child->dn_flags |= DT_NF_REF; /* force pass-by-ref */
1781 		dt_cg_node(dnp->dn_child, dlp, drp);
1782 		dnp->dn_reg = dnp->dn_child->dn_reg;
1783 
1784 		dnp->dn_child->dn_flags &= ~DT_NF_REF;
1785 		dnp->dn_child->dn_flags |= rbit;
1786 		break;
1787 	}
1788 
1789 	case DT_TOK_SIZEOF: {
1790 		size_t size = dt_node_sizeof(dnp->dn_child);
1791 		dnp->dn_reg = dt_regset_alloc(drp);
1792 		assert(size != 0);
1793 		dt_cg_setx(dlp, dnp->dn_reg, size);
1794 		break;
1795 	}
1796 
1797 	case DT_TOK_STRINGOF:
1798 		dt_cg_node(dnp->dn_child, dlp, drp);
1799 		dnp->dn_reg = dnp->dn_child->dn_reg;
1800 		break;
1801 
1802 	case DT_TOK_XLATE:
1803 		/*
1804 		 * An xlate operator appears in either an XLATOR, indicating a
1805 		 * reference to a dynamic translator, or an OP2, indicating
1806 		 * use of the xlate operator in the user's program.  For the
1807 		 * dynamic case, generate an xlate opcode with a reference to
1808 		 * the corresponding member, pre-computed for us in dn_members.
1809 		 */
1810 		if (dnp->dn_kind == DT_NODE_XLATOR) {
1811 			dt_xlator_t *dxp = dnp->dn_xlator;
1812 
1813 			assert(dxp->dx_ident->di_flags & DT_IDFLG_CGREG);
1814 			assert(dxp->dx_ident->di_id != 0);
1815 
1816 			dnp->dn_reg = dt_regset_alloc(drp);
1817 
1818 			if (dxp->dx_arg == -1) {
1819 				instr = DIF_INSTR_MOV(
1820 				    dxp->dx_ident->di_id, dnp->dn_reg);
1821 				dt_irlist_append(dlp,
1822 				    dt_cg_node_alloc(DT_LBL_NONE, instr));
1823 				op = DIF_OP_XLATE;
1824 			} else
1825 				op = DIF_OP_XLARG;
1826 
1827 			instr = DIF_INSTR_XLATE(op, 0, dnp->dn_reg);
1828 			dt_irlist_append(dlp,
1829 			    dt_cg_node_alloc(DT_LBL_NONE, instr));
1830 
1831 			dlp->dl_last->di_extern = dnp->dn_xmember;
1832 			break;
1833 		}
1834 
1835 		assert(dnp->dn_kind == DT_NODE_OP2);
1836 		dt_cg_node(dnp->dn_right, dlp, drp);
1837 		dnp->dn_reg = dnp->dn_right->dn_reg;
1838 		break;
1839 
1840 	case DT_TOK_LPAR:
1841 		dt_cg_node(dnp->dn_right, dlp, drp);
1842 		dnp->dn_reg = dnp->dn_right->dn_reg;
1843 		dt_cg_typecast(dnp->dn_right, dnp, dlp, drp);
1844 		break;
1845 
1846 	case DT_TOK_PTR:
1847 	case DT_TOK_DOT:
1848 		assert(dnp->dn_right->dn_kind == DT_NODE_IDENT);
1849 		dt_cg_node(dnp->dn_left, dlp, drp);
1850 
1851 		/*
1852 		 * If the left-hand side of PTR or DOT is a dynamic variable,
1853 		 * we expect it to be the output of a D translator.   In this
1854 		 * case, we look up the parse tree corresponding to the member
1855 		 * that is being accessed and run the code generator over it.
1856 		 * We then cast the result as if by the assignment operator.
1857 		 */
1858 		if ((idp = dt_node_resolve(
1859 		    dnp->dn_left, DT_IDENT_XLSOU)) != NULL ||
1860 		    (idp = dt_node_resolve(
1861 		    dnp->dn_left, DT_IDENT_XLPTR)) != NULL) {
1862 
1863 			dt_xlator_t *dxp;
1864 			dt_node_t *mnp;
1865 
1866 			dxp = idp->di_data;
1867 			mnp = dt_xlator_member(dxp, dnp->dn_right->dn_string);
1868 			assert(mnp != NULL);
1869 
1870 			dxp->dx_ident->di_flags |= DT_IDFLG_CGREG;
1871 			dxp->dx_ident->di_id = dnp->dn_left->dn_reg;
1872 
1873 			dt_cg_node(mnp->dn_membexpr, dlp, drp);
1874 			dnp->dn_reg = mnp->dn_membexpr->dn_reg;
1875 			dt_cg_typecast(mnp->dn_membexpr, dnp, dlp, drp);
1876 
1877 			dxp->dx_ident->di_flags &= ~DT_IDFLG_CGREG;
1878 			dxp->dx_ident->di_id = 0;
1879 
1880 			if (dnp->dn_left->dn_reg != -1)
1881 				dt_regset_free(drp, dnp->dn_left->dn_reg);
1882 			break;
1883 		}
1884 
1885 		ctfp = dnp->dn_left->dn_ctfp;
1886 		type = ctf_type_resolve(ctfp, dnp->dn_left->dn_type);
1887 
1888 		if (dnp->dn_op == DT_TOK_PTR) {
1889 			type = ctf_type_reference(ctfp, type);
1890 			type = ctf_type_resolve(ctfp, type);
1891 		}
1892 
1893 		if ((ctfp = dt_cg_membinfo(octfp = ctfp, type,
1894 		    dnp->dn_right->dn_string, &m)) == NULL) {
1895 			yypcb->pcb_hdl->dt_ctferr = ctf_errno(octfp);
1896 			longjmp(yypcb->pcb_jmpbuf, EDT_CTF);
1897 		}
1898 
1899 		if (m.ctm_offset != 0) {
1900 			int reg;
1901 
1902 			reg = dt_regset_alloc(drp);
1903 
1904 			/*
1905 			 * If the offset is not aligned on a byte boundary, it
1906 			 * is a bit-field member and we will extract the value
1907 			 * bits below after we generate the appropriate load.
1908 			 */
1909 			dt_cg_setx(dlp, reg, m.ctm_offset / NBBY);
1910 
1911 			instr = DIF_INSTR_FMT(DIF_OP_ADD,
1912 			    dnp->dn_left->dn_reg, reg, dnp->dn_left->dn_reg);
1913 
1914 			dt_irlist_append(dlp,
1915 			    dt_cg_node_alloc(DT_LBL_NONE, instr));
1916 			dt_regset_free(drp, reg);
1917 		}
1918 
1919 		if (!(dnp->dn_flags & DT_NF_REF)) {
1920 			uint_t ubit = dnp->dn_flags & DT_NF_USERLAND;
1921 
1922 			/*
1923 			 * Save and restore DT_NF_USERLAND across dt_cg_load():
1924 			 * we need the sign bit from dnp and the user bit from
1925 			 * dnp->dn_left in order to get the proper opcode.
1926 			 */
1927 			dnp->dn_flags |=
1928 			    (dnp->dn_left->dn_flags & DT_NF_USERLAND);
1929 
1930 			instr = DIF_INSTR_LOAD(dt_cg_load(dnp,
1931 			    ctfp, m.ctm_type), dnp->dn_left->dn_reg,
1932 			    dnp->dn_left->dn_reg);
1933 
1934 			dnp->dn_flags &= ~DT_NF_USERLAND;
1935 			dnp->dn_flags |= ubit;
1936 
1937 			dt_irlist_append(dlp,
1938 			    dt_cg_node_alloc(DT_LBL_NONE, instr));
1939 
1940 			if (dnp->dn_flags & DT_NF_BITFIELD)
1941 				dt_cg_field_get(dnp, dlp, drp, ctfp, &m);
1942 		}
1943 
1944 		dnp->dn_reg = dnp->dn_left->dn_reg;
1945 		break;
1946 
1947 	case DT_TOK_STRING:
1948 		dnp->dn_reg = dt_regset_alloc(drp);
1949 
1950 		assert(dnp->dn_kind == DT_NODE_STRING);
1951 		stroff = dt_strtab_insert(yypcb->pcb_strtab, dnp->dn_string);
1952 
1953 		if (stroff == -1L)
1954 			longjmp(yypcb->pcb_jmpbuf, EDT_NOMEM);
1955 		if (stroff > DIF_STROFF_MAX)
1956 			longjmp(yypcb->pcb_jmpbuf, EDT_STR2BIG);
1957 
1958 		instr = DIF_INSTR_SETS((ulong_t)stroff, dnp->dn_reg);
1959 		dt_irlist_append(dlp, dt_cg_node_alloc(DT_LBL_NONE, instr));
1960 		break;
1961 
1962 	case DT_TOK_IDENT:
1963 		/*
1964 		 * If the specified identifier is a variable on which we have
1965 		 * set the code generator register flag, then this variable
1966 		 * has already had code generated for it and saved in di_id.
1967 		 * Allocate a new register and copy the existing value to it.
1968 		 */
1969 		if (dnp->dn_kind == DT_NODE_VAR &&
1970 		    (dnp->dn_ident->di_flags & DT_IDFLG_CGREG)) {
1971 			dnp->dn_reg = dt_regset_alloc(drp);
1972 			instr = DIF_INSTR_MOV(dnp->dn_ident->di_id,
1973 			    dnp->dn_reg);
1974 			dt_irlist_append(dlp,
1975 			    dt_cg_node_alloc(DT_LBL_NONE, instr));
1976 			break;
1977 		}
1978 
1979 		/*
1980 		 * Identifiers can represent function calls, variable refs, or
1981 		 * symbols.  First we check for inlined variables, and handle
1982 		 * them by generating code for the inline parse tree.
1983 		 */
1984 		if (dnp->dn_kind == DT_NODE_VAR &&
1985 		    (dnp->dn_ident->di_flags & DT_IDFLG_INLINE)) {
1986 			dt_cg_inline(dnp, dlp, drp);
1987 			break;
1988 		}
1989 
1990 		switch (dnp->dn_kind) {
1991 		case DT_NODE_FUNC:
1992 			if ((idp = dnp->dn_ident)->di_kind != DT_IDENT_FUNC) {
1993 				dnerror(dnp, D_CG_EXPR, "%s %s( ) may not be "
1994 				    "called from a D expression (D program "
1995 				    "context required)\n",
1996 				    dt_idkind_name(idp->di_kind), idp->di_name);
1997 			}
1998 
1999 			dt_cg_arglist(dnp->dn_ident, dnp->dn_args, dlp, drp);
2000 
2001 			dnp->dn_reg = dt_regset_alloc(drp);
2002 			instr = DIF_INSTR_CALL(dnp->dn_ident->di_id,
2003 			    dnp->dn_reg);
2004 
2005 			dt_irlist_append(dlp,
2006 			    dt_cg_node_alloc(DT_LBL_NONE, instr));
2007 
2008 			break;
2009 
2010 		case DT_NODE_VAR:
2011 			if (dnp->dn_ident->di_kind == DT_IDENT_XLSOU ||
2012 			    dnp->dn_ident->di_kind == DT_IDENT_XLPTR) {
2013 				/*
2014 				 * This can only happen if we have translated
2015 				 * args[].  See dt_idcook_args() for details.
2016 				 */
2017 				assert(dnp->dn_ident->di_id == DIF_VAR_ARGS);
2018 				dt_cg_array_op(dnp, dlp, drp);
2019 				break;
2020 			}
2021 
2022 			if (dnp->dn_ident->di_kind == DT_IDENT_ARRAY) {
2023 				if (dnp->dn_ident->di_id > DIF_VAR_ARRAY_MAX)
2024 					dt_cg_assoc_op(dnp, dlp, drp);
2025 				else
2026 					dt_cg_array_op(dnp, dlp, drp);
2027 				break;
2028 			}
2029 
2030 			dnp->dn_reg = dt_regset_alloc(drp);
2031 
2032 			if (dnp->dn_ident->di_flags & DT_IDFLG_LOCAL)
2033 				op = DIF_OP_LDLS;
2034 			else if (dnp->dn_ident->di_flags & DT_IDFLG_TLS)
2035 				op = DIF_OP_LDTS;
2036 			else
2037 				op = DIF_OP_LDGS;
2038 
2039 			dnp->dn_ident->di_flags |= DT_IDFLG_DIFR;
2040 
2041 			instr = DIF_INSTR_LDV(op,
2042 			    dnp->dn_ident->di_id, dnp->dn_reg);
2043 
2044 			dt_irlist_append(dlp,
2045 			    dt_cg_node_alloc(DT_LBL_NONE, instr));
2046 			break;
2047 
2048 		case DT_NODE_SYM: {
2049 			dtrace_hdl_t *dtp = yypcb->pcb_hdl;
2050 			dtrace_syminfo_t *sip = dnp->dn_ident->di_data;
2051 			GElf_Sym sym;
2052 
2053 			if (dtrace_lookup_by_name(dtp,
2054 			    sip->dts_object, sip->dts_name, &sym, NULL) == -1) {
2055 				xyerror(D_UNKNOWN, "cg failed for symbol %s`%s:"
2056 				    " %s\n", sip->dts_object, sip->dts_name,
2057 				    dtrace_errmsg(dtp, dtrace_errno(dtp)));
2058 			}
2059 
2060 			dnp->dn_reg = dt_regset_alloc(drp);
2061 			dt_cg_xsetx(dlp, dnp->dn_ident,
2062 			    DT_LBL_NONE, dnp->dn_reg, sym.st_value);
2063 
2064 			if (!(dnp->dn_flags & DT_NF_REF)) {
2065 				instr = DIF_INSTR_LOAD(dt_cg_load(dnp, ctfp,
2066 				    dnp->dn_type), dnp->dn_reg, dnp->dn_reg);
2067 				dt_irlist_append(dlp,
2068 				    dt_cg_node_alloc(DT_LBL_NONE, instr));
2069 			}
2070 			break;
2071 		}
2072 
2073 		default:
2074 			xyerror(D_UNKNOWN, "internal error -- node type %u is "
2075 			    "not valid for an identifier\n", dnp->dn_kind);
2076 		}
2077 		break;
2078 
2079 	case DT_TOK_INT:
2080 		dnp->dn_reg = dt_regset_alloc(drp);
2081 		dt_cg_setx(dlp, dnp->dn_reg, dnp->dn_value);
2082 		break;
2083 
2084 	default:
2085 		xyerror(D_UNKNOWN, "internal error -- token type %u is not a "
2086 		    "valid D compilation token\n", dnp->dn_op);
2087 	}
2088 }
2089 
2090 void
2091 dt_cg(dt_pcb_t *pcb, dt_node_t *dnp)
2092 {
2093 	dif_instr_t instr;
2094 	dt_xlator_t *dxp;
2095 	dt_ident_t *idp;
2096 
2097 	if (pcb->pcb_regs == NULL && (pcb->pcb_regs =
2098 	    dt_regset_create(pcb->pcb_hdl->dt_conf.dtc_difintregs)) == NULL)
2099 		longjmp(pcb->pcb_jmpbuf, EDT_NOMEM);
2100 
2101 	dt_regset_reset(pcb->pcb_regs);
2102 	(void) dt_regset_alloc(pcb->pcb_regs); /* allocate %r0 */
2103 
2104 	if (pcb->pcb_inttab != NULL)
2105 		dt_inttab_destroy(pcb->pcb_inttab);
2106 
2107 	if ((pcb->pcb_inttab = dt_inttab_create(yypcb->pcb_hdl)) == NULL)
2108 		longjmp(pcb->pcb_jmpbuf, EDT_NOMEM);
2109 
2110 	if (pcb->pcb_strtab != NULL)
2111 		dt_strtab_destroy(pcb->pcb_strtab);
2112 
2113 	if ((pcb->pcb_strtab = dt_strtab_create(BUFSIZ)) == NULL)
2114 		longjmp(pcb->pcb_jmpbuf, EDT_NOMEM);
2115 
2116 	dt_irlist_destroy(&pcb->pcb_ir);
2117 	dt_irlist_create(&pcb->pcb_ir);
2118 
2119 	assert(pcb->pcb_dret == NULL);
2120 	pcb->pcb_dret = dnp;
2121 
2122 	if (dt_node_resolve(dnp, DT_IDENT_XLPTR) != NULL) {
2123 		dnerror(dnp, D_CG_DYN, "expression cannot evaluate to result "
2124 		    "of a translated pointer\n");
2125 	}
2126 
2127 	/*
2128 	 * If we're generating code for a translator body, assign the input
2129 	 * parameter to the first available register (i.e. caller passes %r1).
2130 	 */
2131 	if (dnp->dn_kind == DT_NODE_MEMBER) {
2132 		dxp = dnp->dn_membxlator;
2133 		dnp = dnp->dn_membexpr;
2134 
2135 		dxp->dx_ident->di_flags |= DT_IDFLG_CGREG;
2136 		dxp->dx_ident->di_id = dt_regset_alloc(pcb->pcb_regs);
2137 	}
2138 
2139 	dt_cg_node(dnp, &pcb->pcb_ir, pcb->pcb_regs);
2140 
2141 	if ((idp = dt_node_resolve(dnp, DT_IDENT_XLSOU)) != NULL) {
2142 		int reg = dt_cg_xlate_expand(dnp, idp,
2143 		    &pcb->pcb_ir, pcb->pcb_regs);
2144 		dt_regset_free(pcb->pcb_regs, dnp->dn_reg);
2145 		dnp->dn_reg = reg;
2146 	}
2147 
2148 	instr = DIF_INSTR_RET(dnp->dn_reg);
2149 	dt_regset_free(pcb->pcb_regs, dnp->dn_reg);
2150 	dt_irlist_append(&pcb->pcb_ir, dt_cg_node_alloc(DT_LBL_NONE, instr));
2151 
2152 	if (dnp->dn_kind == DT_NODE_MEMBER) {
2153 		dt_regset_free(pcb->pcb_regs, dxp->dx_ident->di_id);
2154 		dxp->dx_ident->di_id = 0;
2155 		dxp->dx_ident->di_flags &= ~DT_IDFLG_CGREG;
2156 	}
2157 
2158 	dt_regset_free(pcb->pcb_regs, 0);
2159 	dt_regset_assert_free(pcb->pcb_regs);
2160 }
2161