Add vec debugging utility to _vec module.

src/lib/_vec.rs

@@ -10,6 +10,7 @@ native "rust" mod rustrt {
    * want to invoke this as vec_alloc[vec[U], U]. */
   fn vec_alloc[T, U](uint n_elts) -> vec[U];
   fn refcount[T](vec[T] v) -> uint;
+  fn vec_print_debug_info[T](vec[T] v);
 }
 
 fn alloc[T](uint n_elts) -> vec[T] {
@@ -58,6 +59,10 @@ fn buf_off[T](vec[T] v, uint offset) -> vbuf {
   ret rustrt.vec_buf[T](v, offset);
 }
 
+fn print_debug_info[T](vec[T] v) {
+  rustrt.vec_print_debug_info[T](v);
+}
+
 // Returns elements from [start..end) from v.
 fn slice[T](vec[T] v, int start, int end) -> vec[T] {
   check(0 <= start);

src/rt/rust_builtin.cpp

@@ -82,7 +82,7 @@ extern "C" CDECL rust_vec*
 vec_alloc(rust_task *task, type_desc *t, type_desc *elem_t, size_t n_elts)
 {
     rust_dom *dom = task->dom;
-    task->log(rust_log::MEM,
+    task->log(rust_log::MEM | rust_log::STDLIB,
               "vec_alloc %" PRIdPTR " elements of size %" PRIdPTR,
               n_elts, elem_t->size);
     size_t fill = n_elts * elem_t->size;
@@ -108,6 +108,23 @@ vec_len(rust_task *task, type_desc *ty, rust_vec *v)
     return v->fill / ty->size;
 }
 
+extern "C" CDECL void
+vec_print_debug_info(rust_task *task, type_desc *ty, rust_vec *v)
+{
+    task->log(rust_log::STDLIB,
+              "vec_print_debug_info(%" PRIxPTR ")"
+              " with tydesc %" PRIxPTR
+              " (size = %" PRIdPTR ", align = %" PRIdPTR ")"
+              " alloc = %" PRIdPTR ", fill = %" PRIdPTR
+              " , data = ...", v, ty, ty->size, ty->align, v->alloc, v->fill);
+
+    for (size_t i = 0; i < v->fill; ++i) {
+        task->log(rust_log::STDLIB,
+                  "  %" PRIdPTR ":    0x%" PRIxPTR,
+                  i, v->data[i]);
+    }
+}
+
 /* Helper for str_alloc and str_from_vec.  Returns NULL as failure. */
 static rust_str *
 str_alloc_with_data(rust_task *task,

src/rt/rust_log.cpp

@@ -26,6 +26,7 @@ read_type_bit_mask() {
         bits |= strstr(env_str, "cache") ? rust_log::CACHE : 0;
         bits |= strstr(env_str, "timer") ? rust_log::TIMER : 0;
         bits |= strstr(env_str, "gc") ? rust_log::GC : 0;
+        bits |= strstr(env_str, "stdlib") ? rust_log::STDLIB : 0;
         bits |= strstr(env_str, "all") ? rust_log::ALL : 0;
         bits = strstr(env_str, "none") ? 0 : bits;
     }

src/rt/rust_log.h

@@ -41,6 +41,7 @@ public:
         UPCALL = 0x200,
         TIMER = 0x400,
         GC = 0x800,
+        STDLIB = 0x1000,
         ALL = 0xffffffff
     };