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#include "all.h"
struct decl *
envfind(const struct env *env, int age, const char *name) {
int eage = INT_MAX;
again:
if (!env)
return NULL;
for (struct decls *decls = env->decls; decls; decls = decls->next) {
if (eage >= decls->decl.age && !strcmp(decls->decl.name, name))
return &decls->decl;
}
env = env->parent;
eage = env && env->parent ? eage : age;
goto again;
}
static bool
declsshadowable(const struct decl *a, const struct decl *b) {
return a->t == Dlet && b->t == Dlet;
}
struct decl *
envput(struct env *env, const struct decl *decl) {
struct decls *decls;
struct env env_noparent = {
.decls = env->decls
};
struct decl *d0;
static int age;
if ((d0 = envfind(&env_noparent, INT_MAX, decl->name))) {
// modify existing forward declarations?
if (decl->t != d0->t)
return NULL;
if (decl == d0 || !memcmp(d0, decl, sizeof *d0))
return d0;
if (d0->t == Ddef && decl->t == Ddef && !memcmp(&d0->var, &decl->var, sizeof d0->var))
return d0;
if (d0->t == Dmacro && !memcmp(&decl->macro, &d0->macro, sizeof decl->macro))
return d0;
if (d0->t == Dtype && d0->ty == decl->ty)
return d0;
if (d0->t == Dfn && !memcmp(&decl->fn, &d0->fn, sizeof decl->fn))
return d0;
if (d0->t == Dtepl && !memcmp(&decl->tepl, &d0->tepl, sizeof decl->tepl))
return d0;
for (int kind = TYstruct; kind <= TYeunion; ++kind) {
if (d0->t == Dtype && d0->ty->t == kind
&& decl->t == Dtype && decl->ty->t == kind && d0->ty->agg.fwd) {
*(size_t *)&d0->ty->size = decl->ty->size;
*(size_t *)&d0->ty->align = decl->ty->align;
*(bool *)&d0->ty->agg.fwd = decl->ty->agg.fwd;
memcpy((void *)&d0->ty->agg.flds, &decl->ty->agg.flds,
sizeof d0->ty->agg.flds);
memcpy((void *)&d0->ty->agg.decls, &decl->ty->agg.decls,
sizeof d0->ty->agg.decls);
d0->span = decl->span;
return d0;
}
}
if (d0->t == Dfn && d0->externp == decl->externp && d0->fn.selfty == decl->fn.selfty && !d0->fn.body && decl->fn.body) {
*(int *)&decl->fn.id = d0->fn.id;
goto ok;
}
if (d0->t == Dfn && d0->externp == decl->externp && d0->fn.selfty == decl->fn.selfty && !d0->fn.body)
return d0;
if (d0->t == Dstatic && d0->externp == decl->externp && d0->var.ty == decl->var.ty && !d0->var.ini)
return d0;
if (d0->t == Dtype && d0->ty == decl->ty)
return d0;
if (!declsshadowable(d0, decl)) {
return NULL;
}
}
ok:
decls = xcalloc(1, sizeof *decls);
decls->next = env->decls;
decls->decl = *decl;
decls->decl.age = age++;
env->decls = decls;
return &decls->decl;
}
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