Support a special const-value refcount, use it for const strings.

3 files changed, 17 insertions, 4 deletions

diff --git a/src/lib/_str.rs b/src/lib/_str.rs
index 0fc7b373..4ea5ca28 100644
--- a/src/lib/_str.rs
+++ b/src/lib/_str.rs
@@ -97,8 +97,13 @@ fn from_bytes(vec[u8] v) : is_utf8(v) -> str {
 }
 
 fn refcount(str s) -> uint {
-    // -1 because calling this function incremented the refcount.
-    ret rustrt.refcount[u8](s) - 1u;
+    auto r = rustrt.refcount[u8](s);
+    if (r == dbg.const_refcount) {
+        ret r;
+    } else {
+        // -1 because calling this function incremented the refcount.
+        ret  r - 1u;
+    }
 }
 
 
diff --git a/src/lib/_vec.rs b/src/lib/_vec.rs
index c2ca95fc..6fa0ed42 100644
--- a/src/lib/_vec.rs
+++ b/src/lib/_vec.rs
@@ -30,8 +30,13 @@ fn alloc[T](uint n_elts) -> vec[T] {
 }
 
 fn refcount[T](vec[T] v) -> uint {
-    // -1 because calling this function incremented the refcount.
-    ret rustrt.refcount[T](v) - 1u;
+    auto r = rustrt.refcount[T](v);
+    if (r == dbg.const_refcount) {
+        ret r;
+    } else {
+        // -1 because calling this function incremented the refcount.
+        ret  r - 1u;
+    }
 }
 
 type init_op[T] = fn(uint i) -> T;
diff --git a/src/lib/dbg.rs b/src/lib/dbg.rs
index 6c856cf7..51a31e07 100644
--- a/src/lib/dbg.rs
+++ b/src/lib/dbg.rs
@@ -7,6 +7,9 @@
 
 import std._vec;
 
+// FIXME: handle 64-bit case.
+const uint const_refcount = 0x7bad_face_u;
+
 native "rust" mod rustrt {
     fn debug_tydesc[T]();
     fn debug_opaque[T](&T x);