From a95e385217841da91c3e44674dbaa95fb613a153 Mon Sep 17 00:00:00 2001
From: lemon <lsof@mailbox.org>
Date: Sun, 14 Sep 2025 11:03:27 +0200
Subject: change freearena for correctness

---
 c.c        |  8 ++++----
 common.h   |  8 ++++----
 mem.c      | 13 +++++++------
 regalloc.c |  1 -
 4 files changed, 15 insertions(+), 15 deletions(-)

diff --git a/c.c b/c.c
index d059cda..6833722 100644
--- a/c.c
+++ b/c.c
@@ -3154,7 +3154,7 @@ stmt(struct comp *cm, struct function *fn)
             useblk(fn, end);
             expreffects(fn, &ex);
             putbranch(fn, begin);
-            freearena(atmpp);
+            freearena(&atmpp);
          } else if (!terminates) putbranch(fn, begin);
          useblk(fn, fl);
       }
@@ -3222,7 +3222,7 @@ stmt(struct comp *cm, struct function *fn)
       EMITS expreffects(fn, &ex);
       break;
    }
-   freearena(cm->exarena);
+   freearena(&cm->exarena);
    return fn->curblk == NULL;
 }
 
@@ -3459,8 +3459,8 @@ docomp(struct comp *cm)
          } else {
             if (ccopt.dbg.p && decl.ty.t) efmt("type %ty\n", decl.ty);
          }
-         freearena(cm->fnarena);
-         freearena(cm->exarena);
+         freearena(&cm->fnarena);
+         freearena(&cm->exarena);
       } while (st.more);
    }
 }
diff --git a/common.h b/common.h
index 6c2e1e9..7848fa1 100644
--- a/common.h
+++ b/common.h
@@ -344,8 +344,9 @@ struct arena {
 #define vec_of(T) struct { T *p; int _cap; uint n; }
 
 /* libc *alloc wrappers */
-extern void *xcalloc(size_t n, const char *);
-extern void *xrealloc(void *, size_t n, const char *);
+void *xcalloc(size_t n, const char *);
+void *xrealloc(void *, size_t n, const char *);
+void free(void *);
 #define xcalloc(n) xcalloc(n, __func__)
 #define xrealloc(p,n) xrealloc(p, n, __func__)
 
@@ -383,13 +384,12 @@ alloccopy(struct arena **arena, const void *src, uint siz, uint align)
 {
    return memcpy(alloc(arena, siz, align), src, siz);
 }
-void freearena(struct arena *);
+void freearena(struct arena **);
 
 void vinit_(void **p, int *pcap, void *inlbuf, int cap, uint siz);
 void vpush_(void **p, int *pcap, uint *pn, uint siz);
 void *vpushn_(void **p, int *pcap, uint *pn, uint siz, const void *dat, uint ndat);
 void vresize_(void **p, int *pcap, uint *pn, uint siz, uint N);
-extern void free(void *);
 #define VINIT(inlbuf, Cap) { (inlbuf), (Cap) }
 #define vfree(v) ((v)->_cap < 0 ? free((v)->p) : (void)0, memset((v), 0, sizeof*(v)))
 #define vinit(v, inlbuf, Cap) (vfree(v), vinit_((void **)&(v)->p, &(v)->_cap, inlbuf, (Cap), sizeof *(v)->p))
diff --git a/mem.c b/mem.c
index b673986..8ed87eb 100644
--- a/mem.c
+++ b/mem.c
@@ -124,16 +124,17 @@ allocz(struct arena **par, uint siz, uint align)
 }
 
 void
-freearena(struct arena *ar)
+freearena(struct arena **par)
 {
    struct arena *prev;
-   for (; ar; ar = prev) {
-      prev = ar->prev;
-      if (ar->dyn)
-         free(ar);
+   for (; *par; *par = prev) {
+      prev = (*par)->prev;
+      if ((*par)->dyn)
+         free(*par);
       else {
          assert(!prev);
-         ar->n = 0;
+         (*par)->n = 0;
+         return;
       }
    }
 }
diff --git a/regalloc.c b/regalloc.c
index c71c803..b7516d0 100644
--- a/regalloc.c
+++ b/regalloc.c
@@ -1107,7 +1107,6 @@ regalloc(struct function *fn)
       irdump(fn);
    }
    fn->regusage = globusage;
-   freearena(ra.arena);
 }
 
 
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