backend/outbuf: Add bounds checks (in DEBUG builds)

dlang · Sep 13, 2015 · d537ec8 · d537ec8
1 parent 381e65f
commit d537ec8
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Showing 2 changed files with 12 additions and 0 deletions.
diff --git a/src/backend/outbuf.c b/src/backend/outbuf.c
@@ -264,6 +264,10 @@ char *Outbuffer::toString()
 void Outbuffer::setsize(size_t size)
 {
     p = buf + size;
+
+#ifdef DEBUG
+    assert(p <= pend); // Attempting to seek past end of buffer
+#endif
 }
 
 void Outbuffer::writesLEB128(int value)

diff --git a/src/backend/outbuf.h b/src/backend/outbuf.h
@@ -13,6 +13,10 @@
 
 #include        <string.h>
 
+#ifdef DEBUG
+#include        <assert.h>
+#endif
+
 // Output buffer
 
 // (This used to be called OutBuffer, we renamed it to avoid name conflicts with Mars.)
@@ -40,6 +44,10 @@ struct Outbuffer
     // Reserve nbytes in buffer
     void reserve(size_t nbytes)
     {
+        #ifdef DEBUG
+        assert(buf <= p && p <= pend); // Wrote past the end of the buffer!
+        #endif
+
         if (pend - p < nbytes)
             enlarge(nbytes);
     }