From 6bceaa4a60da1f075bdd3133d7d95d8d5d7a06ac Mon Sep 17 00:00:00 2001
From: Nicholas Noll <nbnoll@eml.cc>
Date: Sat, 30 May 2020 19:54:27 -0700
Subject: fix: many use before initialization bugs

---
 sys/cmd/cc/ast.c | 37 ++++++++++++++++++++++++++++++++++---
 sys/cmd/cc/cc.c  | 12 ++++++++++++
 sys/cmd/cc/cc.h  |  3 +++
 3 files changed, 49 insertions(+), 3 deletions(-)

(limited to 'sys/cmd/cc')

diff --git a/sys/cmd/cc/ast.c b/sys/cmd/cc/ast.c
index 4c81509..6a3ed9f 100644
--- a/sys/cmd/cc/ast.c
+++ b/sys/cmd/cc/ast.c
@@ -98,6 +98,30 @@ putname(Parser *p, Name *n)
     *p->nm-- = (Name){0};
 }
 
+static
+Ptr*
+getptr(Parser *p)
+{
+    if (p->pt >= arrend(p->ptstk))
+        panicf("pointer stack overflow");
+
+    return p->pt++;
+}
+
+static
+void
+putptr(Parser *p, Ptr *ptr)
+{
+    if (p->pt <= p->ptstk) 
+        panicf("pointer stack underflow");
+
+    while ((ptr = ptr->link))
+        putptr(p, ptr);
+
+    *p->pt-- = (Ptr){0};
+}
+
+
 static
 Dtor*
 getdtor(Parser *p)
@@ -106,7 +130,6 @@ getdtor(Parser *p)
         panicf("dtor stack overflow");
 
     p->dt->name = getname(p);
-    p->dt->ptr  = (Ptr){ 0 };
     return p->dt++;
 }
 
@@ -117,6 +140,10 @@ putdtor(Parser *p, Dtor *dt)
     if (p->dt <= p->dtstk) 
         panicf("dtor stack underflow");
 
+    /* release the pointer overflow if we had to use it */
+    if (p->dt->ptr.link)
+        putptr(p, p->dt->ptr.link);
+
     /* the dtor could encompass multiple names hierarchically */
     putname(p, dt->name);
     *p->dt-- = (Dtor){0};
@@ -898,8 +925,11 @@ stmt(Parser *p, Lexer *lx)
 
         if (sym->kind == Stype)
             goto Tdecl;
-        if (sym->kind == Svar)
+        if (sym->kind == Svar) {
+            alloc(s);
+            s->pos.beg = lx->pos;
             goto Texpr;
+        }
 
         errorat(lx->pos, "bad symbol type used as type identifier");
         goto Bad;
@@ -1919,6 +1949,7 @@ dtor(Parser *p, Lexer *lx, Dtor *d, int ab)
             goto Name;
         goto Bad;
     }
+    n = 0;
 Ptr:
     ptr->kind |= Bit(n);
     advance(p, lx);
@@ -1937,7 +1968,7 @@ Key:
             
     case Astar:
         if (++n >= 8) {
-            alloc(x);
+            x = getptr(p);
             x->kind   = 0;
             x->link   = nil;
             ptr->link = x;
diff --git a/sys/cmd/cc/cc.c b/sys/cmd/cc/cc.c
index da4c4ed..3246292 100644
--- a/sys/cmd/cc/cc.c
+++ b/sys/cmd/cc/cc.c
@@ -277,9 +277,21 @@ freelx(Lexer *lx)
 void
 initp(Parser *p)
 {
+    /* initialize temporary buffers */
+    memset(p->spstk, 0, sizeof(p->spstk));
+    memset(p->nmstk, 0, sizeof(p->nmstk));
+    memset(p->dtstk, 0, sizeof(p->dtstk));
+    memset(p->ptstk, 0, sizeof(p->ptstk));
+
     p->sp = p->spstk;
     p->nm = p->nmstk;
     p->dt = p->dtstk;
+    p->pt = p->ptstk;
+
+    /* initialize ast */
+    p->ast.cap   = 0;
+    p->ast.len   = 0;
+    p->ast.decls = nil;
 }
 
 error
diff --git a/sys/cmd/cc/cc.h b/sys/cmd/cc/cc.h
index d030b91..de1ec3f 100644
--- a/sys/cmd/cc/cc.h
+++ b/sys/cmd/cc/cc.h
@@ -728,6 +728,9 @@ struct Parser
     Name  *nm;
     Name   nmstk[40];
 
+    Ptr   *pt;
+    Ptr    ptstk[10];
+
     Dtor  *dt;
     Dtor   dtstk[40];
 };
-- 
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