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/ir/sourceloc.rs

@@ -0,0 +1,63 @@
+//! Source locations.
+//!
+//! Cranelift tracks the original source location of each instruction, and preserves the source
+//! location when instructions are transformed.
+
+use core::fmt;
+
+/// A source location.
+///
+/// This is an opaque 32-bit number attached to each Cranelift IR instruction. Cranelift does not
+/// interpret source locations in any way, they are simply preserved from the input to the output.
+///
+/// The default source location uses the all-ones bit pattern `!0`. It is used for instructions
+/// that can't be given a real source location.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub struct SourceLoc(u32);
+
+impl SourceLoc {
+    /// Create a new source location with the given bits.
+    pub fn new(bits: u32) -> Self {
+        SourceLoc(bits)
+    }
+
+    /// Is this the default source location?
+    pub fn is_default(self) -> bool {
+        self == Default::default()
+    }
+
+    /// Read the bits of this source location.
+    pub fn bits(self) -> u32 {
+        self.0
+    }
+}
+
+impl Default for SourceLoc {
+    fn default() -> Self {
+        SourceLoc(!0)
+    }
+}
+
+impl fmt::Display for SourceLoc {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        if self.is_default() {
+            write!(f, "@-")
+        } else {
+            write!(f, "@{:04x}", self.0)
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::ir::SourceLoc;
+    use std::string::ToString;
+
+    #[test]
+    fn display() {
+        assert_eq!(SourceLoc::default().to_string(), "@-");
+        assert_eq!(SourceLoc::new(0).to_string(), "@0000");
+        assert_eq!(SourceLoc::new(16).to_string(), "@0010");
+        assert_eq!(SourceLoc::new(0xabcdef).to_string(), "@abcdef");
+    }
+}