scc

  1#include <stdlib.h>
  2#include <string.h>
  3
  4#include <scc/scc.h>
  5
  6#include "cc2.h"
  7
  8#define NNODES   32
  9
 10Symbol *curfun;
 11
 12static Alloc *arena;
 13static Node *curstmt;
 14
 15Node *
 16node(int op)
 17{
 18	Node *np;
 19
 20	if (!arena)
 21		arena = alloc(sizeof(Node), NNODES);
 22	np = memset(new(arena), 0, sizeof(*np));
 23	np->op = op;
 24
 25	return np;
 26}
 27
 28#ifndef NDEBUG
 29#include <stdio.h>
 30
 31static void
 32prnode(Node *np)
 33{
 34	if (!np)
 35		return;
 36	prnode(np->left);
 37	prnode(np->right);
 38
 39	switch (np->op) {
 40	case OBRANCH:
 41	case OJMP:
 42		fprintf(stderr,
 43		        "\t%c -> L%u",
 44		        np->op, np->u.sym->numid);
 45		break;
 46	case OCONST:
 47		fprintf(stderr,
 48		        "\t%c%lu{%llu}",
 49		        np->op, np->type.size, np->u.i);
 50		break;
 51	case OAUTO:
 52	case OREG:
 53	case OMEM:
 54	case OLABEL:
 55	case OTMP:
 56		fprintf(stderr,
 57		        "\t%c%lu[%u]",
 58		        np->op, np->type.size, np->u.sym->numid);
 59		break;
 60	default:
 61		fprintf(stderr,
 62		        "\t%c%lu",
 63		        np->op, np->type.size);
 64		break;
 65	}
 66	fprintf(stderr,"(%d,%d)", np->complex, np->address);
 67}
 68
 69void
 70prtree(Node *np)
 71{
 72	Block *bb;
 73
 74	bb = np->bb;
 75
 76	if (np->flags & BBENTRY)
 77		putc('>', stderr);
 78	fprintf(stderr, "(%d)",  bb ? bb->id : 0);
 79	if (np->flags & BBEXIT)
 80		putc('>', stderr);
 81	putc('\t', stderr);
 82	if (np->label)
 83		fprintf(stderr, "L%u:", np->label->numid);
 84
 85	prnode(np);
 86	putc('\n', stderr);
 87}
 88
 89void
 90prforest(char *msg)
 91{
 92	Node *np;
 93
 94	fprintf(stderr, "tree %s {\n", msg);
 95	for (np = curfun->u.stmt; np; np = np->next)
 96		prtree(np);
 97	fputs("}\n", stderr);
 98}
 99#endif
100
101Node *
102insstmt(Node *np, Node *at)
103{
104	Node *next;
105
106	next = at->next;
107	if (next)
108		next->prev = np;
109	at->next = np;
110
111	np->next = next;
112	np->prev = at;
113
114	return np;
115}
116
117Node *
118unlinkstmt(Node *np)
119{
120	Node *next, *prev;
121
122	next = np->next;
123	prev = np->prev;
124	if (next)
125		next->prev = prev;
126	if (prev)
127		prev->next = next;
128	np->next = np->prev = NULL;
129
130	return np;
131}
132
133Node *
134prestmt(Node *np)
135{
136	return insstmt(np, curstmt->prev);
137}
138
139Node *
140savelabel(void)
141{
142	Symbol *label = curstmt->label;
143
144	if (label) {
145		prestmt(labelstmt(NULL, label));
146		curstmt->label = NULL;
147	}
148	return curstmt;
149}
150
151Node *
152addstmt(Node *np)
153{
154	insstmt(np, curstmt);
155	return curstmt = np;
156}
157
158Node *
159delstmt(Node *np)
160{
161	Node *next;
162
163	next = np->next;
164	deltree(unlinkstmt(np));
165	return next;
166}
167
168void
169delnode(Node *np)
170{
171	delete(arena, np);
172}
173
174void
175deltree(Node *np)
176{
177	if (!np)
178		return;
179	deltree(np->left);
180	deltree(np->right);
181	delnode(np);
182}
183
184void
185cleannodes(void)
186{
187	if (arena) {
188		dealloc(arena);
189		arena = NULL;
190	}
191	curfun = NULL;
192}
193
194void
195newfun(Symbol *sym, Node *np)
196{
197	curfun = sym;
198	curstmt = curfun->u.stmt = np;
199}
200
201void
202delrange(Node *begin, Node *end)
203{
204	Node *lprev, *rnext, *next, *np;
205
206	lprev = begin->prev;
207	rnext = end->next;
208
209	if (lprev)
210		lprev->next = rnext;
211	if (rnext)
212		rnext->prev = lprev;
213
214	for (np = begin; np != rnext; np = next) {
215		next = np->next;
216		deltree(np);
217	}
218}
219
220void
221apply(Node *(*fun)(Node *))
222{
223	Node *np, *ocurstmt;
224
225	for (curstmt = curfun->u.stmt; curstmt; curstmt = np) {
226		ocurstmt = curstmt;
227		np = (*fun)(curstmt);
228		np = (np) ? np->next : delstmt(ocurstmt);
229	}
230}