moved crates in lib/ to src/, renamed crates, modified some files' text (#660)

moved crates in lib/ to src/, renamed crates, modified some files' text (#660)

cranelift/codegen/src/dbg.rs

@@ -0,0 +1,28 @@
+//! Debug tracing helpers.
+use core::fmt;
+
+/// Prefix added to the log file names, just before the thread name or id.
+pub static LOG_FILENAME_PREFIX: &str = "cranelift.dbg.";
+
+/// Helper for printing lists.
+pub struct DisplayList<'a, T>(pub &'a [T])
+where
+    T: 'a + fmt::Display;
+
+impl<'a, T> fmt::Display for DisplayList<'a, T>
+where
+    T: 'a + fmt::Display,
+{
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match self.0.split_first() {
+            None => write!(f, "[]"),
+            Some((first, rest)) => {
+                write!(f, "[{}", first)?;
+                for x in rest {
+                    write!(f, ", {}", x)?;
+                }
+                write!(f, "]")
+            }
+        }
+    }
+}