114 lines
2.6 KiB
Plaintext
114 lines
2.6 KiB
Plaintext
// selfhost/cmd/wcc/sym.ww — port of cmd/wcc/sym.c.
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//
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// Per-scope hashtable, chained to the parent. Lookup walks up.
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// Plan 9 / Hare flavoured. Duplicate definitions in the same scope
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// return nil; the caller flags the error.
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use mem;
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use typ;
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use ast;
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// Symbol kinds — must stay numerically aligned with cmd/wcc/ww.h Skind.
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def SK_NONE: i32 = 0;
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def SK_VAR: i32 = 1;
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def SK_PARAM: i32 = 2;
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def SK_DEF: i32 = 3;
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def SK_TYPE: i32 = 4;
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def SK_FN: i32 = 5;
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def SK_USE: i32 = 6;
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def SK_FIELD: i32 = 7;
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type sym = struct {
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name: str,
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skind: i32,
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type_: *tinfo,
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decl: *node,
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exported: i32,
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snext: *sym, // iteration order
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hashnext: *sym, // hash bucket chain
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scope: *scope,
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};
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def NBUCKETS: i32 = 16;
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type scope = struct {
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parent: *scope,
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first: *sym,
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last: *sym,
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buckets: **sym, // length = NBUCKETS
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nbuckets: i32,
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a: *arena,
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};
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// FNV-1a 64 — same hash the C side uses, so bucket distribution is
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// identical when both walk a scope in declaration order.
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fn hashstr(s: str) u64 = {
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let h: u64 = 14695981039346656037u64;
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let i: i32 = 0;
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for (i < s.len) {
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let c: u8 = s[i];
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h = h ^ (c: u64);
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h = h * 1099511628211u64;
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i += 1;
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};
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return h;
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};
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export fn newscope(a: *arena, parent: *scope) *scope = {
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let s: *scope = amalloc(a, 64u64): *scope;
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s.parent = parent;
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s.a = a;
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s.nbuckets = NBUCKETS;
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s.buckets = amalloc(a, (NBUCKETS: u64) * 8u64): **sym;
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return s;
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};
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export fn streq(a: str, b: str) bool = {
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if (a.len != b.len) { return false; };
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let i: i32 = 0;
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for (i < a.len) {
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if (a[i] != b[i]) { return false; };
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i += 1;
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};
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return true;
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};
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export fn scopelookuplocal(s: *scope, name: str) *sym = {
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if (s == nil) { return nil; };
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let h: u64 = hashstr(name);
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let bi: i32 = (h % (s.nbuckets: u64)): i32;
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let b: *sym = s.buckets[bi];
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for (b != nil) {
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let bn: str = b.name;
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if (streq(bn, name)) { return b; };
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b = b.hashnext;
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};
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return nil;
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};
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export fn scopelookup(s: *scope, name: str) *sym = {
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for (s != nil) {
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let r: *sym = scopelookuplocal(s, name);
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if (r != nil) { return r; };
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s = s.parent;
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};
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return nil;
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};
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export fn scopedefine(s: *scope, name: str, k: i32, t: *tinfo, decl: *node) *sym = {
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if (scopelookuplocal(s, name) != nil) { return nil; };
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let sy: *sym = amalloc(s.a, 80u64): *sym;
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sy.name = name;
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sy.skind = k;
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sy.type_ = t;
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sy.decl = decl;
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sy.scope = s;
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let h: u64 = hashstr(name);
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let bi: i32 = (h % (s.nbuckets: u64)): i32;
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sy.hashnext = s.buckets[bi];
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s.buckets[bi] = sy;
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if (s.first == nil) { s.first = sy; } else { s.last.snext = sy; };
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s.last = sy;
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return sy;
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};
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