Hojun-Cho
1657bdeda3
C bootstrap (phases 0-9):
cmd/wwc, cmd/6c, cmd/6a, cmd/6l, cmd/ww, rt, lib/*.
ww-side self-host (phase 10):
selfhost/cmd/wwc — ww-cgen frontend; bootstrap fixed point.
selfhost/cmd/6a — assembler; byte-identical to C 6a (test 991).
selfhost/cmd/6l — linker w/ archive (.a) support; byte-identical
to C 6l (test 992).
selfhost/cmd/ww — driver (build/run/version); byte-identical to
C ww (test 993).
make test: 15/15. make bootstrap: ww2.s == ww3.s, ww2.o == ww3.o,
ww2 == ww3 byte-identical, with the full ww-tooled chain.
118 lines
2.2 KiB
C
118 lines
2.2 KiB
C
/*
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* mem.c — arena allocator. No free per allocation; freearena releases
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* the whole chain. Aligned to 16 so structs with 8-byte fields and
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* doubles are happy.
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*
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* Hot allocations in the compiler land in arenas: tokens, AST nodes,
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* symbols, types. The chunk size doubles up to a cap so we don't
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* fragment on huge inputs.
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*/
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#include "ww.h"
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#include <stdlib.h>
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#include <string.h>
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#define ALIGN 16
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#define INIT_CHUNK (64 * 1024)
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#define MAX_CHUNK (4 * 1024 * 1024)
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static u64
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roundup(u64 n, u64 a)
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{
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return (n + a - 1) & ~(a - 1);
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}
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Arena *
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newarena(void)
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{
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Arena *a = calloc(1, sizeof *a);
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if (a == NULL)
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fatal("newarena: out of memory");
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a->buf = malloc(INIT_CHUNK);
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if (a->buf == NULL)
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fatal("newarena: out of memory");
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a->cap = INIT_CHUNK;
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return a;
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}
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static void
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grow(Arena *a, u64 need)
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{
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u64 ncap = a->cap * 2;
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if (ncap > MAX_CHUNK)
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ncap = MAX_CHUNK;
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if (ncap < need)
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ncap = roundup(need, ALIGN);
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/* push current chunk onto chain, allocate fresh head */
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Arena *old = malloc(sizeof *old);
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if (old == NULL)
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fatal("arena: oom");
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*old = *a;
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a->next = old;
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a->buf = malloc(ncap);
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if (a->buf == NULL)
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fatal("arena: oom (chunk=%llu)", (unsigned long long)ncap);
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a->off = 0;
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a->cap = ncap;
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}
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void *
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amalloc(Arena *a, u64 n)
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{
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n = roundup(n, ALIGN);
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if (n > a->cap - a->off)
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grow(a, n);
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void *p = a->buf + a->off;
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a->off += n;
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a->total += n;
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memset(p, 0, n);
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return p;
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}
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char *
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astrdup(Arena *a, const char *s)
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{
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u64 n = strlen(s);
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char *p = amalloc(a, n + 1);
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memcpy(p, s, n);
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return p;
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}
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char *
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astrndup(Arena *a, const char *s, u64 n)
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{
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char *p = amalloc(a, n + 1);
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memcpy(p, s, n);
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return p;
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}
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char *
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aprintf(Arena *a, const char *fmt, ...)
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{
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va_list ap;
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va_start(ap, fmt);
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int n = vsnprintf(NULL, 0, fmt, ap);
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va_end(ap);
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if (n < 0)
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fatal("aprintf: vsnprintf failed");
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char *p = amalloc(a, (u64)n + 1);
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va_start(ap, fmt);
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vsnprintf(p, (size_t)n + 1, fmt, ap);
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va_end(ap);
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return p;
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}
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void
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freearena(Arena *a)
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{
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while (a) {
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Arena *next = a->next;
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free(a->buf);
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/* The head Arena was returned by newarena() and is the only
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* one we should free as a struct; the linked older ones were
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* allocated by grow() and are also freeable. */
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free(a);
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a = next;
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}
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}
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