From 6ea22d950fd7246c9159a3601819ae23d03e8dcd Mon Sep 17 00:00:00 2001
From: Nicholas Noll <nbnoll@eml.cc>
Date: Wed, 20 May 2020 12:22:30 -0700
Subject: fix: truncate infinite recursion caused by self referential macros

---
 sys/cmd/cc/cc.c  | 7 ++++---
 sys/cmd/cc/cc.h  | 2 +-
 sys/cmd/cc/lex.c | 4 ++--
 3 files changed, 7 insertions(+), 6 deletions(-)

(limited to 'sys')

diff --git a/sys/cmd/cc/cc.c b/sys/cmd/cc/cc.c
index 6338050..00cd4a5 100644
--- a/sys/cmd/cc/cc.c
+++ b/sys/cmd/cc/cc.c
@@ -130,13 +130,13 @@ openio(byte *path)
 } 
 
 Io*
-makeio()
+makeio(byte *name)
 {
     if ((C.io - C.iostk) >= arrlen(C.iostk)-1) 
         panicf("out of I/O space!");
 
-    C.io->path = "<buffer>";
-    C.io->buf = (io·Buffer) {
+    C.io->path = name;
+    C.io->buf  = (io·Buffer) {
         .state    = bufio·rdr | bufio·end, 
         .runesize = 0,
         .h        = nil,
@@ -163,6 +163,7 @@ freeio(Io *io)
     io->link      = nil;
     io->path      = nil;
     io->store     = (Pos){ 0 };
+    io->path      = "<empty>";
 }
 
 void
diff --git a/sys/cmd/cc/cc.h b/sys/cmd/cc/cc.h
index 6ed2caa..685dce2 100644
--- a/sys/cmd/cc/cc.h
+++ b/sys/cmd/cc/cc.h
@@ -388,7 +388,7 @@ struct Io
 
 /* cc.c io functions */
 Io*  openio(byte *path);
-Io*  makeio();
+Io*  makeio(byte *name);
 void freeio(Io *io);
 
 struct StrTab
diff --git a/sys/cmd/cc/lex.c b/sys/cmd/cc/lex.c
index 8ce4e79..4cc1259 100644
--- a/sys/cmd/cc/lex.c
+++ b/sys/cmd/cc/lex.c
@@ -635,8 +635,8 @@ Dispatch:
         } 
 
         sym = lookup(&lx->sym, tok.val.s);
-        if (sym) {
-            io = makeio();
+        if (sym && ((uintptr)sym->name != (uintptr)lx->io->path)) {
+            io = makeio(sym->name);
             printf("EXPANDING MACRO %s\n", sym->name);
             io->buf.end   += expandmacro(lx, sym, io->b);
             *io->buf.end++ = EOF;
-- 
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