| 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 | } |