Commit | Line | Data |
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5ab61658 BJ |
1 | /* Copyright (c) 1979 Regents of the University of California */ |
2 | # | |
3 | /* | |
4 | * pi - Pascal interpreter code translator | |
5 | * | |
6 | * Charles Haley, Bill Joy UCB | |
7 | * Version 1.1 February 1978 | |
8 | * | |
9 | * | |
10 | * pxp - Pascal execution profiler | |
11 | * | |
12 | * Bill Joy UCB | |
13 | * Version 1.1 February 1978 | |
14 | */ | |
15 | ||
16 | #include "0.h" | |
17 | ||
18 | /* | |
19 | * TREE SPACE DECLARATIONS | |
20 | */ | |
21 | struct tr { | |
22 | int *tr_low; | |
23 | int *tr_high; | |
24 | } ttab[MAXTREE], *tract; | |
25 | ||
26 | /* | |
27 | * The variable space is the | |
28 | * absolute base of the tree segments. | |
29 | * (exactly the same as ttab[0].tr_low) | |
30 | * Spacep is maintained to point at the | |
31 | * beginning of the next tree slot to | |
32 | * be allocated for use by the grammar. | |
33 | * Spacep is used "extern" by the semantic | |
34 | * actions in pas.y. | |
35 | * The variable tract is maintained to point | |
36 | * at the tree segment out of which we are | |
37 | * allocating (the active segment). | |
38 | */ | |
39 | int *space, *spacep; | |
40 | ||
41 | /* | |
42 | * TREENMAX is the maximum width | |
43 | * in words that any tree node | |
44 | * due to the way in which the parser uses | |
45 | * the pointer spacep. | |
46 | */ | |
47 | #define TREENMAX 6 | |
48 | ||
49 | int trspace[ITREE]; | |
50 | int *space = trspace; | |
51 | int *spacep = trspace; | |
52 | struct tr *tract = ttab; | |
53 | ||
54 | /* | |
55 | * Inittree allocates the first tree slot | |
56 | * and sets up the first segment descriptor. | |
57 | * A lot of this work is actually done statically | |
58 | * above. | |
59 | */ | |
60 | inittree() | |
61 | { | |
62 | ||
63 | ttab[0].tr_low = space; | |
64 | ttab[0].tr_high = &space[ITREE]; | |
65 | } | |
66 | ||
67 | /* | |
68 | * Tree builds the nodes in the | |
69 | * parse tree. It is rarely called | |
70 | * directly, rather calls are made | |
71 | * to tree[12345] which supplies the | |
72 | * first argument to save space in | |
73 | * the code. Tree also guarantees | |
74 | * that spacep points to the beginning | |
75 | * of the next slot it will return, | |
76 | * a property required by the parser | |
77 | * which was always true before we | |
78 | * segmented the tree space. | |
79 | */ | |
80 | int *tree(cnt, a) | |
81 | int cnt; | |
82 | { | |
83 | register int *p, *q; | |
84 | register int i; | |
85 | ||
86 | i = cnt; | |
87 | p = spacep; | |
88 | q = &a; | |
89 | do | |
90 | *p++ = *q++; | |
91 | while (--i); | |
92 | q = spacep; | |
93 | spacep = p; | |
94 | if (p+TREENMAX >= tract->tr_high) | |
95 | /* | |
96 | * this peek-ahead should | |
97 | * save a great number of calls | |
98 | * to tralloc. | |
99 | */ | |
100 | tralloc(TREENMAX); | |
101 | return (q); | |
102 | } | |
103 | ||
104 | /* | |
105 | * Tralloc preallocates enough | |
106 | * space in the tree to allow | |
107 | * the grammar to use the variable | |
108 | * spacep, as it did before the | |
109 | * tree was segmented. | |
110 | */ | |
111 | tralloc(howmuch) | |
112 | { | |
113 | register char *cp; | |
114 | register i; | |
115 | ||
116 | if (spacep + howmuch >= tract->tr_high) { | |
117 | i = TRINC; | |
118 | cp = malloc(i * sizeof ( int )); | |
119 | if (cp == -1) { | |
120 | yerror("Ran out of memory (tralloc)"); | |
121 | pexit(DIED); | |
122 | } | |
123 | spacep = cp; | |
124 | tract++; | |
125 | if (tract >= &ttab[MAXTREE]) { | |
126 | yerror("Ran out of tree tables"); | |
127 | pexit(DIED); | |
128 | } | |
129 | tract->tr_low = cp; | |
130 | tract->tr_high = tract->tr_low+i; | |
131 | } | |
132 | } | |
133 | ||
134 | extern int yylacnt; | |
135 | extern bottled; | |
136 | #ifdef PXP | |
137 | #endif | |
138 | /* | |
139 | * Free up the tree segments | |
140 | * at the end of a block. | |
141 | * If there is scanner lookahead, | |
142 | * i.e. if yylacnt != 0 or there is bottled output, then we | |
143 | * cannot free the tree space. | |
144 | * This happens only when errors | |
145 | * occur and the forward move extends | |
146 | * across "units". | |
147 | */ | |
148 | trfree() | |
149 | { | |
150 | ||
151 | if (yylacnt != 0 || bottled != NIL) | |
152 | return; | |
153 | #ifdef PXP | |
154 | if (needtree()) | |
155 | return; | |
156 | #endif | |
157 | spacep = space; | |
158 | while (tract->tr_low > spacep || tract->tr_high <= spacep) { | |
159 | free(tract->tr_low); | |
160 | tract->tr_low = NIL; | |
161 | tract->tr_high = NIL; | |
162 | tract--; | |
163 | if (tract < ttab) | |
164 | panic("ttab"); | |
165 | } | |
166 | #ifdef PXP | |
167 | packtree(); | |
168 | #endif | |
169 | } | |
170 | ||
171 | /* | |
172 | * Copystr copies a token from | |
173 | * the "token" buffer into the | |
174 | * tree space. | |
175 | */ | |
176 | copystr(token) | |
177 | register char *token; | |
178 | { | |
179 | register char *cp; | |
180 | register int i; | |
181 | ||
182 | i = (strlen(token) + sizeof ( int )) & ~( ( sizeof ( int ) ) - 1 ); | |
183 | tralloc(i / sizeof ( int )); | |
184 | strcpy(spacep, token); | |
185 | cp = spacep; | |
186 | spacep = cp + i; | |
187 | tralloc(TREENMAX); | |
188 | return (cp); | |
189 | } |