diff --git a/src/librustc/driver/driver.rs b/src/librustc/driver/driver.rs
index f1c64a7e0995f42ce9ea446e8128726135d013d9..4879ae30699a18536c6fc0d7e355c92d0f34a2db 100644
--- a/src/librustc/driver/driver.rs
+++ b/src/librustc/driver/driver.rs
@@ -354,7 +354,7 @@ fn ann_identified_post(node: pprust::ann_node) {
       ppm_expanded | ppm_normal => pprust::no_ann()
     };
     let is_expanded = upto != cu_parse;
-    let src = codemap::get_filemap(sess.codemap, source_name(input)).src;
+    let src = sess.codemap.get_filemap(source_name(input)).src;
     do io::with_str_reader(*src) |rdr| {
         pprust::print_crate(sess.codemap, sess.parse_sess.interner,
                             sess.span_diagnostic, crate,
@@ -574,7 +574,7 @@ fn build_session_options(binary: ~str,
 
 fn build_session(sopts: @session::options,
                  demitter: diagnostic::emitter) -> Session {
-    let codemap = @codemap::new_codemap();
+    let codemap = @codemap::CodeMap::new();
     let diagnostic_handler =
         diagnostic::mk_handler(Some(demitter));
     let span_diagnostic_handler =
diff --git a/src/librustc/metadata/encoder.rs b/src/librustc/metadata/encoder.rs
index 07fc637a04933f60e33b78658edfa788534fa33b..5aed12dba959412429909efa9019f95313b8a7ae 100644
--- a/src/librustc/metadata/encoder.rs
+++ b/src/librustc/metadata/encoder.rs
@@ -557,7 +557,7 @@ fn add_to_index_(item: @item, ebml_w: ebml::Serializer,
     let add_to_index = |copy ebml_w| add_to_index_(item, ebml_w, index);
 
     debug!("encoding info for item at %s",
-           syntax::codemap::span_to_str(item.span, ecx.tcx.sess.codemap));
+           ecx.tcx.sess.codemap.span_to_str(item.span));
 
     match item.node {
       item_const(_, _) => {
diff --git a/src/librustc/middle/liveness.rs b/src/librustc/middle/liveness.rs
index ec7c2ffc6f1da789bac90f45f91e759a9defed42..ed9549cedd7e63ef3b549838165c435625e5a75b 100644
--- a/src/librustc/middle/liveness.rs
+++ b/src/librustc/middle/liveness.rs
@@ -97,7 +97,7 @@
 use syntax::{visit, ast_util};
 use syntax::print::pprust::{expr_to_str, block_to_str};
 use visit::vt;
-use syntax::codemap::{span, span_to_str};
+use syntax::codemap::span;
 use syntax::ast::*;
 use io::WriterUtil;
 use capture::{cap_move, cap_drop, cap_copy, cap_ref};
@@ -170,9 +170,9 @@ impl LiveNodeKind : cmp::Eq {
 fn live_node_kind_to_str(lnk: LiveNodeKind, cx: ty::ctxt) -> ~str {
     let cm = cx.sess.codemap;
     match lnk {
-        FreeVarNode(s) => fmt!("Free var node [%s]", span_to_str(s, cm)),
-        ExprNode(s)    => fmt!("Expr node [%s]", span_to_str(s, cm)),
-        VarDefNode(s)  => fmt!("Var def node [%s]", span_to_str(s, cm)),
+        FreeVarNode(s) => fmt!("Free var node [%s]", cm.span_to_str(s)),
+        ExprNode(s)    => fmt!("Expr node [%s]", cm.span_to_str(s)),
+        VarDefNode(s)  => fmt!("Var def node [%s]", cm.span_to_str(s)),
         ExitNode       => ~"Exit node"
     }
 }
diff --git a/src/librustc/middle/trans/base.rs b/src/librustc/middle/trans/base.rs
index f509c15ab5f8df688bd94a8e8b79a3262e162922..4941885cafb5465b70af0be6448b2e3cf562d996 100644
--- a/src/librustc/middle/trans/base.rs
+++ b/src/librustc/middle/trans/base.rs
@@ -919,7 +919,7 @@ fn trans_trace(bcx: block, sp_opt: Option<span>, trace_str: ~str) {
     let {V_filename, V_line} = match sp_opt {
       Some(sp) => {
         let sess = bcx.sess();
-        let loc = codemap::lookup_char_pos(sess.parse_sess.cm, sp.lo);
+        let loc = sess.parse_sess.cm.lookup_char_pos(sp.lo);
         {V_filename: C_cstr(bcx.ccx(), loc.file.name),
          V_line: loc.line as int}
       }
diff --git a/src/librustc/middle/trans/build.rs b/src/librustc/middle/trans/build.rs
index f7690b7bc93004dd38fa05a75bc766a38c4bfb28..f980990517495ff27aa707c029b2976fa6100f10 100644
--- a/src/librustc/middle/trans/build.rs
+++ b/src/librustc/middle/trans/build.rs
@@ -645,7 +645,7 @@ fn _UndefReturn(cx: block, Fn: ValueRef) -> ValueRef {
 fn add_span_comment(bcx: block, sp: span, text: ~str) {
     let ccx = bcx.ccx();
     if !ccx.sess.no_asm_comments() {
-        let s = text + ~" (" + codemap::span_to_str(sp, ccx.sess.codemap)
+        let s = text + ~" (" + ccx.sess.codemap.span_to_str(sp)
             + ~")";
         log(debug, s);
         add_comment(bcx, s);
diff --git a/src/librustc/middle/trans/controlflow.rs b/src/librustc/middle/trans/controlflow.rs
index 59a733433bf22b09d6fad00f115b8137d250f6f9..0c09b02bb07b108da688bff7ae929d6a62c38bec 100644
--- a/src/librustc/middle/trans/controlflow.rs
+++ b/src/librustc/middle/trans/controlflow.rs
@@ -339,7 +339,7 @@ fn trans_fail_value(bcx: block, sp_opt: Option<span>, V_fail_str: ValueRef)
     let {V_filename, V_line} = match sp_opt {
       Some(sp) => {
         let sess = bcx.sess();
-        let loc = codemap::lookup_char_pos(sess.parse_sess.cm, sp.lo);
+        let loc = sess.parse_sess.cm.lookup_char_pos(sp.lo);
         {V_filename: C_cstr(bcx.ccx(), loc.file.name),
          V_line: loc.line as int}
       }
@@ -361,7 +361,7 @@ fn trans_fail_bounds_check(bcx: block, sp: span,
     let _icx = bcx.insn_ctxt("trans_fail_bounds_check");
     let ccx = bcx.ccx();
 
-    let loc = codemap::lookup_char_pos(bcx.sess().parse_sess.cm, sp.lo);
+    let loc = bcx.sess().parse_sess.cm.lookup_char_pos(sp.lo);
     let line = C_int(ccx, loc.line as int);
     let filename_cstr = C_cstr(bcx.ccx(), loc.file.name);
     let filename = PointerCast(bcx, filename_cstr, T_ptr(T_i8()));
diff --git a/src/librustc/middle/trans/debuginfo.rs b/src/librustc/middle/trans/debuginfo.rs
index c794b0189fc2eaa96bc0bf8b0a68ca4d9bff97ff..2575141f7c45ba27cf96d92de99c2f56e2bf290d 100644
--- a/src/librustc/middle/trans/debuginfo.rs
+++ b/src/librustc/middle/trans/debuginfo.rs
@@ -230,7 +230,7 @@ fn create_file(cx: @crate_ctxt, full_path: ~str) -> @metadata<file_md> {
 }
 
 fn line_from_span(cm: @codemap::CodeMap, sp: span) -> uint {
-    codemap::lookup_char_pos(cm, sp.lo).line
+    cm.lookup_char_pos(sp.lo).line
 }
 
 fn create_block(cx: block) -> @metadata<block_md> {
@@ -244,9 +244,9 @@ fn create_block(cx: block) -> @metadata<block_md> {
     }
     let sp = cx.node_info.get().span;
 
-    let start = codemap::lookup_char_pos(cx.sess().codemap, sp.lo);
+    let start = cx.sess().codemap.lookup_char_pos(sp.lo);
     let fname = start.file.name;
-    let end = codemap::lookup_char_pos(cx.sess().codemap, sp.hi);
+    let end = cx.sess().codemap.lookup_char_pos(sp.hi);
     let tg = LexicalBlockTag;
     /*alt cached_metadata::<@metadata<block_md>>(
         cache, tg,
@@ -597,7 +597,7 @@ fn t_to_ty(cx: crate_ctxt, t: ty::t, span: span) -> @ast::ty {
 }
 
 fn filename_from_span(cx: @crate_ctxt, sp: codemap::span) -> ~str {
-    codemap::lookup_char_pos(cx.sess.codemap, sp.lo).file.name
+    cx.sess.codemap.lookup_char_pos(sp.lo).file.name
 }
 
 fn create_var(type_tag: int, context: ValueRef, name: ~str, file: ValueRef,
@@ -629,8 +629,7 @@ fn create_local_var(bcx: block, local: @ast::local)
       // FIXME this should be handled (#2533)
       _ => fail ~"no single variable name for local"
     };
-    let loc = codemap::lookup_char_pos(cx.sess.codemap,
-                                       local.span.lo);
+    let loc = cx.sess.codemap.lookup_char_pos(local.span.lo);
     let ty = node_id_type(bcx, local.node.id);
     let tymd = create_ty(cx, ty, local.node.ty);
     let filemd = create_file(cx, loc.file.name);
@@ -674,8 +673,7 @@ fn create_arg(bcx: block, arg: ast::arg, sp: span)
       option::None => ()
     }
 
-    let loc = codemap::lookup_char_pos(cx.sess.codemap,
-                                       sp.lo);
+    let loc = cx.sess.codemap.lookup_char_pos(sp.lo);
     let ty = node_id_type(bcx, arg.id);
     let tymd = create_ty(cx, ty, arg.ty);
     let filemd = create_file(cx, loc.file.name);
@@ -714,7 +712,7 @@ fn update_source_pos(cx: block, s: span) {
     }
     let cm = cx.sess().codemap;
     let blockmd = create_block(cx);
-    let loc = codemap::lookup_char_pos(cm, s.lo);
+    let loc = cm.lookup_char_pos(s.lo);
     let scopedata = ~[lli32(loc.line as int),
                      lli32(loc.col as int),
                      blockmd.node,
@@ -731,7 +729,7 @@ fn create_function(fcx: fn_ctxt) -> @metadata<subprogram_md> {
     log(debug, fcx.id);
 
     let sp = fcx.span.get();
-    log(debug, codemap::span_to_str(sp, cx.sess.codemap));
+    log(debug, cx.sess.codemap.span_to_str(sp));
 
     let (ident, ret_ty, id) = match cx.tcx.items.get(fcx.id) {
       ast_map::node_item(item, _) => {
@@ -773,8 +771,7 @@ fn create_function(fcx: fn_ctxt) -> @metadata<subprogram_md> {
       option::None => ()
     }
 
-    let loc = codemap::lookup_char_pos(cx.sess.codemap,
-                                       sp.lo);
+    let loc = cx.sess.codemap.lookup_char_pos(sp.lo);
     let file_node = create_file(cx, loc.file.name).node;
     let ty_node = if cx.sess.opts.extra_debuginfo {
         match ret_ty.node {
diff --git a/src/librustc/middle/typeck/infer/region_inference.rs b/src/librustc/middle/typeck/infer/region_inference.rs
index bdc764a8d0b098f604b2573428de0ced66b49c5e..652d99779d3120672ca5c38da45383ae075784e8 100644
--- a/src/librustc/middle/typeck/infer/region_inference.rs
+++ b/src/librustc/middle/typeck/infer/region_inference.rs
@@ -507,7 +507,7 @@ fn new_region_var(&self, span: span) -> RegionVid {
             self.undo_log.push(AddVar(vid));
         }
         debug!("created new region variable %? with span %?",
-               vid, codemap::span_to_str(span, self.tcx.sess.codemap));
+               vid, self.tcx.sess.codemap.span_to_str(span));
         return vid;
     }
 
diff --git a/src/librustc/util/ppaux.rs b/src/librustc/util/ppaux.rs
index a9b67a7ff29c994c00ef20812aa612326cf73849..7ef71c0cc2fc60591a3ecc560f838e15de66b427 100644
--- a/src/librustc/util/ppaux.rs
+++ b/src/librustc/util/ppaux.rs
@@ -105,7 +105,7 @@ fn explain_region_and_span(cx: ctxt, region: ty::Region)
     fn explain_span(cx: ctxt, heading: ~str, span: span)
         -> (~str, Option<span>)
     {
-        let lo = codemap::lookup_char_pos_adj(cx.sess.codemap, span.lo);
+        let lo = cx.sess.codemap.lookup_char_pos_adj(span.lo);
         (fmt!("the %s at %u:%u", heading, lo.line, lo.col), Some(span))
     }
 }
@@ -131,17 +131,17 @@ fn re_scope_id_to_str(cx: ctxt, node_id: ast::node_id) -> ~str {
     match cx.items.find(node_id) {
       Some(ast_map::node_block(blk)) => {
         fmt!("<block at %s>",
-             codemap::span_to_str(blk.span, cx.sess.codemap))
+             cx.sess.codemap.span_to_str(blk.span))
       }
       Some(ast_map::node_expr(expr)) => {
         match expr.node {
           ast::expr_call(*) => {
             fmt!("<call at %s>",
-                 codemap::span_to_str(expr.span, cx.sess.codemap))
+                 cx.sess.codemap.span_to_str(expr.span))
           }
           ast::expr_match(*) => {
             fmt!("<alt at %s>",
-                 codemap::span_to_str(expr.span, cx.sess.codemap))
+                 cx.sess.codemap.span_to_str(expr.span))
           }
           ast::expr_assign_op(*) |
           ast::expr_field(*) |
@@ -149,11 +149,11 @@ fn re_scope_id_to_str(cx: ctxt, node_id: ast::node_id) -> ~str {
           ast::expr_binary(*) |
           ast::expr_index(*) => {
             fmt!("<method at %s>",
-                 codemap::span_to_str(expr.span, cx.sess.codemap))
+                 cx.sess.codemap.span_to_str(expr.span))
           }
           _ => {
             fmt!("<expression at %s>",
-                 codemap::span_to_str(expr.span, cx.sess.codemap))
+                 cx.sess.codemap.span_to_str(expr.span))
           }
         }
       }
diff --git a/src/librustdoc/astsrv.rs b/src/librustdoc/astsrv.rs
index 480fc6c3914b4b48830e1c280aeecd0187f787a6..cb97d38b208542d908672b0065b56356a3dd209a 100644
--- a/src/librustdoc/astsrv.rs
+++ b/src/librustdoc/astsrv.rs
@@ -120,7 +120,7 @@ fn build_ctxt(sess: Session,
 
 fn build_session() -> Session {
     let sopts: @options = basic_options();
-    let codemap = @codemap::new_codemap();
+    let codemap = @codemap::CodeMap::new();
     let error_handlers = build_error_handlers(codemap);
     let {emitter, span_handler} = error_handlers;
 
diff --git a/src/libsyntax/codemap.rs b/src/libsyntax/codemap.rs
index 6a0e8063119e873ca1b259acec0773f368f91bfc..f204cf89e1b573ba3f71db6ad222104a6a863a0d 100644
--- a/src/libsyntax/codemap.rs
+++ b/src/libsyntax/codemap.rs
@@ -58,6 +58,11 @@ impl file_pos : cmp::Eq {
     pure fn ne(other: &file_pos) -> bool { !self.eq(other) }
 }
 
+pub struct file_lines {
+    file: @filemap,
+    lines: ~[uint]
+}
+
 pub enum file_substr {
     pub fss_none,
     pub fss_internal(span),
@@ -90,173 +95,173 @@ pub impl filemap {
         return filemap::new_w_substr(filename, fss_none, src,
                                      start_pos_ch, start_pos_byte);
     }
-}
 
-pub struct CodeMap {
-    files: DVec<@filemap>
-}
+    fn next_line(@self, chpos: uint, byte_pos: uint) {
+        self.lines.push(file_pos {ch: chpos, byte: byte_pos + self.start_pos.byte});
+    }
 
-pub fn new_codemap() -> CodeMap {
-    CodeMap {
-        files: DVec()
+    pub fn get_line(@self, line: int) -> ~str unsafe {
+        let begin: uint = self.lines[line].byte - self.start_pos.byte;
+        let end = match str::find_char_from(*self.src, '\n', begin) {
+            Some(e) => e,
+            None => str::len(*self.src)
+        };
+        str::slice(*self.src, begin, end)
     }
-}
 
-pub fn mk_substr_filename(cm: @CodeMap, sp: span) -> ~str
-{
-    let pos = lookup_char_pos(cm, sp.lo);
-    return fmt!("<%s:%u:%u>", pos.file.name, pos.line, pos.col);
 }
 
-pub fn next_line(file: @filemap, chpos: uint, byte_pos: uint) {
-    file.lines.push(file_pos {ch: chpos, byte: byte_pos + file.start_pos.byte});
+pub struct CodeMap {
+    files: DVec<@filemap>
 }
 
-fn lookup_line(map: @CodeMap, pos: uint, lookup: lookup_fn)
-    -> {fm: @filemap, line: uint}
-{
-    let len = map.files.len();
-    let mut a = 0u;
-    let mut b = len;
-    while b - a > 1u {
-        let m = (a + b) / 2u;
-        if lookup(map.files[m].start_pos) > pos { b = m; } else { a = m; }
-    }
-    if (a >= len) {
-        fail fmt!("position %u does not resolve to a source location", pos)
+pub impl CodeMap {
+    static pub fn new() -> CodeMap {
+        CodeMap {
+            files: DVec()
+        }
     }
-    let f = map.files[a];
-    a = 0u;
-    b = vec::len(f.lines);
-    while b - a > 1u {
-        let m = (a + b) / 2u;
-        if lookup(f.lines[m]) > pos { b = m; } else { a = m; }
+
+    pub fn mk_substr_filename(@self, sp: span) -> ~str {
+        let pos = self.lookup_char_pos(sp.lo);
+        return fmt!("<%s:%u:%u>", pos.file.name, pos.line, pos.col);
     }
-    return {fm: f, line: a};
-}
 
-fn lookup_pos(map: @CodeMap, pos: uint, lookup: lookup_fn) -> loc {
-    let {fm: f, line: a} = lookup_line(map, pos, lookup);
-    return loc {file: f, line: a + 1u, col: pos - lookup(f.lines[a])};
-}
+    pub fn lookup_char_pos(@self, pos: uint) -> loc {
+        pure fn lookup(pos: file_pos) -> uint { return pos.ch; }
+        return self.lookup_pos(pos, lookup);
+    }
 
-pub fn lookup_char_pos(map: @CodeMap, pos: uint) -> loc {
-    pure fn lookup(pos: file_pos) -> uint { return pos.ch; }
-    return lookup_pos(map, pos, lookup);
-}
+    pub fn lookup_byte_pos(@self, pos: uint) -> loc {
+        pure fn lookup(pos: file_pos) -> uint { return pos.byte; }
+        return self.lookup_pos(pos, lookup);
+    }
 
-fn lookup_byte_pos(map: @CodeMap, pos: uint) -> loc {
-    pure fn lookup(pos: file_pos) -> uint { return pos.byte; }
-    return lookup_pos(map, pos, lookup);
-}
+    pub fn lookup_char_pos_adj(@self, pos: uint)
+        -> {filename: ~str, line: uint, col: uint, file: Option<@filemap>}
+    {
+        let loc = self.lookup_char_pos(pos);
+        match (loc.file.substr) {
+            fss_none => {
+                {filename: /* FIXME (#2543) */ copy loc.file.name,
+                 line: loc.line,
+                 col: loc.col,
+                 file: Some(loc.file)}
+            }
+            fss_internal(sp) => {
+                self.lookup_char_pos_adj(sp.lo + (pos - loc.file.start_pos.ch))
+            }
+            fss_external(eloc) => {
+                {filename: /* FIXME (#2543) */ copy eloc.filename,
+                 line: eloc.line + loc.line - 1u,
+                 col: if loc.line == 1u {eloc.col + loc.col} else {loc.col},
+                 file: None}
+            }
+        }
+    }
 
-pub fn lookup_char_pos_adj(map: @CodeMap, pos: uint)
-    -> {filename: ~str, line: uint, col: uint, file: Option<@filemap>}
-{
-    let loc = lookup_char_pos(map, pos);
-    match (loc.file.substr) {
-      fss_none => {
-        {filename: /* FIXME (#2543) */ copy loc.file.name,
-         line: loc.line,
-         col: loc.col,
-         file: Some(loc.file)}
-      }
-      fss_internal(sp) => {
-        lookup_char_pos_adj(map, sp.lo + (pos - loc.file.start_pos.ch))
-      }
-      fss_external(eloc) => {
-        {filename: /* FIXME (#2543) */ copy eloc.filename,
-         line: eloc.line + loc.line - 1u,
-         col: if loc.line == 1u {eloc.col + loc.col} else {loc.col},
-         file: None}
-      }
+    pub fn adjust_span(@self, sp: span) -> span {
+        pure fn lookup(pos: file_pos) -> uint { return pos.ch; }
+        let line = self.lookup_line(sp.lo, lookup);
+        match (line.fm.substr) {
+            fss_none => sp,
+            fss_internal(s) => {
+                self.adjust_span(span {lo: s.lo + (sp.lo - line.fm.start_pos.ch),
+                                       hi: s.lo + (sp.hi - line.fm.start_pos.ch),
+                                       expn_info: sp.expn_info})}
+            fss_external(_) => sp
+        }
     }
-}
 
-pub fn adjust_span(map: @CodeMap, sp: span) -> span {
-    pure fn lookup(pos: file_pos) -> uint { return pos.ch; }
-    let line = lookup_line(map, sp.lo, lookup);
-    match (line.fm.substr) {
-      fss_none => sp,
-      fss_internal(s) => {
-        adjust_span(map, span {lo: s.lo + (sp.lo - line.fm.start_pos.ch),
-                               hi: s.lo + (sp.hi - line.fm.start_pos.ch),
-                               expn_info: sp.expn_info})}
-      fss_external(_) => sp
+    pub fn span_to_str(@self, sp: span) -> ~str {
+        let lo = self.lookup_char_pos_adj(sp.lo);
+        let hi = self.lookup_char_pos_adj(sp.hi);
+        return fmt!("%s:%u:%u: %u:%u", lo.filename,
+                    lo.line, lo.col, hi.line, hi.col)
     }
-}
 
-fn span_to_str_no_adj(sp: span, cm: @CodeMap) -> ~str {
-    let lo = lookup_char_pos(cm, sp.lo);
-    let hi = lookup_char_pos(cm, sp.hi);
-    return fmt!("%s:%u:%u: %u:%u", lo.file.name,
-             lo.line, lo.col, hi.line, hi.col)
-}
+    pub fn span_to_filename(@self, sp: span) -> filename {
+        let lo = self.lookup_char_pos(sp.lo);
+        return /* FIXME (#2543) */ copy lo.file.name;
+    }
 
-pub fn span_to_str(sp: span, cm: @CodeMap) -> ~str {
-    let lo = lookup_char_pos_adj(cm, sp.lo);
-    let hi = lookup_char_pos_adj(cm, sp.hi);
-    return fmt!("%s:%u:%u: %u:%u", lo.filename,
-             lo.line, lo.col, hi.line, hi.col)
-}
+    pub fn span_to_lines(@self, sp: span) -> @file_lines {
+        let lo = self.lookup_char_pos(sp.lo);
+        let hi = self.lookup_char_pos(sp.hi);
+        let mut lines = ~[];
+        for uint::range(lo.line - 1u, hi.line as uint) |i| {
+            lines.push(i);
+        };
+        return @file_lines {file: lo.file, lines: lines};
+    }
 
-pub struct file_lines {
-    file: @filemap,
-    lines: ~[uint]
-}
+    fn lookup_byte_offset(@self, chpos: uint)
+        -> {fm: @filemap, pos: uint} {
+        pure fn lookup(pos: file_pos) -> uint { return pos.ch; }
+        let {fm, line} = self.lookup_line(chpos, lookup);
+        let line_offset = fm.lines[line].byte - fm.start_pos.byte;
+        let col = chpos - fm.lines[line].ch;
+        let col_offset = str::count_bytes(*fm.src, line_offset, col);
+        {fm: fm, pos: line_offset + col_offset}
+    }
 
-pub fn span_to_filename(sp: span, cm: @codemap::CodeMap) -> filename {
-    let lo = lookup_char_pos(cm, sp.lo);
-    return /* FIXME (#2543) */ copy lo.file.name;
-}
+    pub fn span_to_snippet(@self, sp: span) -> ~str {
+        let begin = self.lookup_byte_offset(sp.lo);
+        let end = self.lookup_byte_offset(sp.hi);
+        assert begin.fm.start_pos == end.fm.start_pos;
+        return str::slice(*begin.fm.src, begin.pos, end.pos);
+    }
 
-pub fn span_to_lines(sp: span, cm: @codemap::CodeMap) -> @file_lines {
-    let lo = lookup_char_pos(cm, sp.lo);
-    let hi = lookup_char_pos(cm, sp.hi);
-    let mut lines = ~[];
-    for uint::range(lo.line - 1u, hi.line as uint) |i| {
-        lines.push(i);
-    };
-    return @file_lines {file: lo.file, lines: lines};
-}
+    pub fn get_snippet(@self, fidx: uint, lo: uint, hi: uint) -> ~str
+    {
+        let fm = self.files[fidx];
+        return str::slice(*fm.src, lo, hi)
+    }
 
-pub fn get_line(fm: @filemap, line: int) -> ~str unsafe {
-    let begin: uint = fm.lines[line].byte - fm.start_pos.byte;
-    let end = match str::find_char_from(*fm.src, '\n', begin) {
-      Some(e) => e,
-      None => str::len(*fm.src)
-    };
-    str::slice(*fm.src, begin, end)
-}
+    pub fn get_filemap(@self, filename: ~str) -> @filemap {
+        for self.files.each |fm| { if fm.name == filename { return *fm; } }
+        //XXjdm the following triggers a mismatched type bug
+        //      (or expected function, found _|_)
+        fail; // ("asking for " + filename + " which we don't know about");
+    }
 
-fn lookup_byte_offset(cm: @codemap::CodeMap, chpos: uint)
-    -> {fm: @filemap, pos: uint} {
-    pure fn lookup(pos: file_pos) -> uint { return pos.ch; }
-    let {fm, line} = lookup_line(cm, chpos, lookup);
-    let line_offset = fm.lines[line].byte - fm.start_pos.byte;
-    let col = chpos - fm.lines[line].ch;
-    let col_offset = str::count_bytes(*fm.src, line_offset, col);
-    {fm: fm, pos: line_offset + col_offset}
 }
 
-pub fn span_to_snippet(sp: span, cm: @codemap::CodeMap) -> ~str {
-    let begin = lookup_byte_offset(cm, sp.lo);
-    let end = lookup_byte_offset(cm, sp.hi);
-    assert begin.fm.start_pos == end.fm.start_pos;
-    return str::slice(*begin.fm.src, begin.pos, end.pos);
-}
+priv impl CodeMap {
+    fn lookup_line(@self, pos: uint, lookup: lookup_fn)
+        -> {fm: @filemap, line: uint}
+    {
+        let len = self.files.len();
+        let mut a = 0u;
+        let mut b = len;
+        while b - a > 1u {
+            let m = (a + b) / 2u;
+            if lookup(self.files[m].start_pos) > pos { b = m; } else { a = m; }
+        }
+        if (a >= len) {
+            fail fmt!("position %u does not resolve to a source location", pos)
+        }
+        let f = self.files[a];
+        a = 0u;
+        b = vec::len(f.lines);
+        while b - a > 1u {
+            let m = (a + b) / 2u;
+            if lookup(f.lines[m]) > pos { b = m; } else { a = m; }
+        }
+        return {fm: f, line: a};
+    }
 
-pub fn get_snippet(cm: @codemap::CodeMap, fidx: uint, lo: uint, hi: uint) -> ~str
-{
-    let fm = cm.files[fidx];
-    return str::slice(*fm.src, lo, hi)
-}
+    fn lookup_pos(@self, pos: uint, lookup: lookup_fn) -> loc {
+        let {fm: f, line: a} = self.lookup_line(pos, lookup);
+        return loc {file: f, line: a + 1u, col: pos - lookup(f.lines[a])};
+    }
 
-pub fn get_filemap(cm: @CodeMap, filename: ~str) -> @filemap {
-    for cm.files.each |fm| { if fm.name == filename { return *fm; } }
-    //XXjdm the following triggers a mismatched type bug
-    //      (or expected function, found _|_)
-    fail; // ("asking for " + filename + " which we don't know about");
+    fn span_to_str_no_adj(@self, sp: span) -> ~str {
+        let lo = self.lookup_char_pos(sp.lo);
+        let hi = self.lookup_char_pos(sp.hi);
+        return fmt!("%s:%u:%u: %u:%u", lo.file.name,
+                    lo.line, lo.col, hi.line, hi.col)
+    }
 }
 
 //
diff --git a/src/libsyntax/diagnostic.rs b/src/libsyntax/diagnostic.rs
index 9335faed0c9872fe21c71a6dff61b9eaa033eb64..66c59683813a8c4c00e7eb2acde3a389d08fcaaf 100644
--- a/src/libsyntax/diagnostic.rs
+++ b/src/libsyntax/diagnostic.rs
@@ -192,9 +192,9 @@ fn print_diagnostic(topic: ~str, lvl: level, msg: &str) {
 fn emit(cmsp: Option<(@codemap::CodeMap, span)>, msg: &str, lvl: level) {
     match cmsp {
       Some((cm, sp)) => {
-        let sp = codemap::adjust_span(cm,sp);
-        let ss = codemap::span_to_str(sp, cm);
-        let lines = codemap::span_to_lines(sp, cm);
+        let sp = cm.adjust_span(sp);
+        let ss = cm.span_to_str(sp);
+        let lines = cm.span_to_lines(sp);
         print_diagnostic(ss, lvl, msg);
         highlight_lines(cm, sp, lines);
         print_macro_backtrace(cm, sp);
@@ -221,7 +221,7 @@ fn highlight_lines(cm: @codemap::CodeMap, sp: span,
     // Print the offending lines
     for display_lines.each |line| {
         io::stderr().write_str(fmt!("%s:%u ", fm.name, *line + 1u));
-        let s = codemap::get_line(fm, *line as int) + ~"\n";
+        let s = fm.get_line(*line as int) + ~"\n";
         io::stderr().write_str(s);
     }
     if elided {
@@ -237,7 +237,7 @@ fn highlight_lines(cm: @codemap::CodeMap, sp: span,
 
     // If there's one line at fault we can easily point to the problem
     if vec::len(lines.lines) == 1u {
-        let lo = codemap::lookup_char_pos(cm, sp.lo);
+        let lo = cm.lookup_char_pos(sp.lo);
         let mut digits = 0u;
         let mut num = (lines.lines[0] + 1u) / 10u;
 
@@ -250,7 +250,7 @@ fn highlight_lines(cm: @codemap::CodeMap, sp: span,
         while left > 0u { str::push_char(&mut s, ' '); left -= 1u; }
 
         s += ~"^";
-        let hi = codemap::lookup_char_pos(cm, sp.hi);
+        let hi = cm.lookup_char_pos(sp.hi);
         if hi.col != lo.col {
             // the ^ already takes up one space
             let mut width = hi.col - lo.col - 1u;
@@ -263,10 +263,10 @@ fn highlight_lines(cm: @codemap::CodeMap, sp: span,
 fn print_macro_backtrace(cm: @codemap::CodeMap, sp: span) {
     do option::iter(&sp.expn_info) |ei| {
         let ss = option::map_default(&ei.callie.span, @~"",
-                                     |span| @codemap::span_to_str(*span, cm));
+                                     |span| @cm.span_to_str(*span));
         print_diagnostic(*ss, note,
                          fmt!("in expansion of %s!", ei.callie.name));
-        let ss = codemap::span_to_str(ei.call_site, cm);
+        let ss = cm.span_to_str(ei.call_site);
         print_diagnostic(ss, note, ~"expansion site");
         print_macro_backtrace(cm, ei.call_site);
     }
diff --git a/src/libsyntax/ext/qquote.rs b/src/libsyntax/ext/qquote.rs
index af7ffaa73f5bf03ec6b74d260dcf6089c9fff771..6ae083779cd1b174de15f2bed20d2a54b264b6fa 100644
--- a/src/libsyntax/ext/qquote.rs
+++ b/src/libsyntax/ext/qquote.rs
@@ -204,13 +204,13 @@ fn finish<T: qq_helper>
     -> @ast::expr
 {
     let cm = ecx.codemap();
-    let str = @codemap::span_to_snippet(body.span, cm);
+    let str = @cm.span_to_snippet(body.span);
     debug!("qquote--str==%?", str);
-    let fname = codemap::mk_substr_filename(cm, body.span);
+    let fname = cm.mk_substr_filename(body.span);
     let node = parse_from_source_str
         (f, fname, codemap::fss_internal(body.span), str,
          ecx.cfg(), ecx.parse_sess());
-    let loc = codemap::lookup_char_pos(cm, body.span.lo);
+    let loc = cm.lookup_char_pos(body.span.lo);
 
     let sp = node.span();
     let qcx = gather_anti_quotes(sp.lo, node);
diff --git a/src/libsyntax/ext/source_util.rs b/src/libsyntax/ext/source_util.rs
index 3181a6044007cd78b356224e48149a1a41c95987..8c5048b4c6f7ae4c322121f90df5adb99e7c9475 100644
--- a/src/libsyntax/ext/source_util.rs
+++ b/src/libsyntax/ext/source_util.rs
@@ -16,7 +16,7 @@
 fn expand_line(cx: ext_ctxt, sp: span, arg: ast::mac_arg,
                _body: ast::mac_body) -> @ast::expr {
     get_mac_args(cx, sp, arg, 0u, option::Some(0u), ~"line");
-    let loc = codemap::lookup_char_pos(cx.codemap(), sp.lo);
+    let loc = cx.codemap().lookup_char_pos(sp.lo);
     return mk_uint(cx, sp, loc.line);
 }
 
@@ -24,7 +24,7 @@ fn expand_line(cx: ext_ctxt, sp: span, arg: ast::mac_arg,
 fn expand_col(cx: ext_ctxt, sp: span, arg: ast::mac_arg,
               _body: ast::mac_body) -> @ast::expr {
     get_mac_args(cx, sp, arg, 0u, option::Some(0u), ~"col");
-    let loc = codemap::lookup_char_pos(cx.codemap(), sp.lo);
+    let loc = cx.codemap().lookup_char_pos(sp.lo);
     return mk_uint(cx, sp, loc.col);
 }
 
@@ -35,7 +35,7 @@ fn expand_file(cx: ext_ctxt, sp: span, arg: ast::mac_arg,
                _body: ast::mac_body) -> @ast::expr {
     get_mac_args(cx, sp, arg, 0u, option::Some(0u), ~"file");
     let loc { file: @filemap { name: filename, _ }, _ } =
-        codemap::lookup_char_pos(cx.codemap(), sp.lo);
+        cx.codemap().lookup_char_pos(sp.lo);
     return mk_uniq_str(cx, sp, filename);
 }
 
@@ -103,7 +103,7 @@ fn expand_include_bin(cx: ext_ctxt, sp: codemap::span, arg: ast::mac_arg,
 fn res_rel_file(cx: ext_ctxt, sp: codemap::span, arg: &Path) -> Path {
     // NB: relative paths are resolved relative to the compilation unit
     if !arg.is_absolute {
-        let cu = Path(codemap::span_to_filename(sp, cx.codemap()));
+        let cu = Path(cx.codemap().span_to_filename(sp));
         cu.dir_path().push_many(arg.components)
     } else {
         copy *arg
diff --git a/src/libsyntax/parse.rs b/src/libsyntax/parse.rs
index f93be9c7266c84d14be5d62476cb1b37f3a994fa..3f15a5b6e88649f0b0154223b391ef7cdcfb4ee7 100644
--- a/src/libsyntax/parse.rs
+++ b/src/libsyntax/parse.rs
@@ -20,7 +20,7 @@
 use diagnostic::{span_handler, mk_span_handler, mk_handler, emitter};
 use lexer::{reader, string_reader};
 use parse::token::{ident_interner, mk_ident_interner};
-use codemap::filemap;
+use codemap::{CodeMap, filemap};
 
 type parse_sess = @{
     cm: @codemap::CodeMap,
@@ -33,7 +33,7 @@
 };
 
 fn new_parse_sess(demitter: Option<emitter>) -> parse_sess {
-    let cm = @codemap::new_codemap();
+    let cm = @CodeMap::new();
     return @{cm: cm,
              mut next_id: 1,
              span_diagnostic: mk_span_handler(mk_handler(demitter), cm),
diff --git a/src/libsyntax/parse/lexer.rs b/src/libsyntax/parse/lexer.rs
index f3e84a0cbf8eaaab528ac7813238fd414fbf05ff..1c984ad57b1f926dde88d6181aee9083357b738e 100644
--- a/src/libsyntax/parse/lexer.rs
+++ b/src/libsyntax/parse/lexer.rs
@@ -1,5 +1,5 @@
 use diagnostic::span_handler;
-use codemap::span;
+use codemap::{span, CodeMap};
 use ext::tt::transcribe::{tt_reader,  new_tt_reader, dup_tt_reader,
                              tt_next_token};
 
@@ -135,7 +135,7 @@ fn bump(rdr: string_reader) {
         rdr.col += 1u;
         rdr.chpos += 1u;
         if rdr.curr == '\n' {
-            codemap::next_line(rdr.filemap, rdr.chpos, rdr.pos);
+            rdr.filemap.next_line(rdr.chpos, rdr.pos);
             rdr.col = 0u;
         }
         let next = str::char_range_at(*rdr.src, rdr.pos);
@@ -232,9 +232,9 @@ fn consume_any_line_comment(rdr: string_reader)
         }
     } else if rdr.curr == '#' {
         if nextch(rdr) == '!' {
-            let cmap = @codemap::new_codemap();
+            let cmap = @CodeMap::new();
             (*cmap).files.push(rdr.filemap);
-            let loc = codemap::lookup_char_pos_adj(cmap, rdr.chpos);
+            let loc = cmap.lookup_char_pos_adj(rdr.chpos);
             if loc.line == 1u && loc.col == 0u {
                 while rdr.curr != '\n' && !is_eof(rdr) { bump(rdr); }
                 return consume_whitespace_and_comments(rdr);
diff --git a/src/libsyntax/print/pprust.rs b/src/libsyntax/print/pprust.rs
index 2bf9b826d6fae37cfbd54cb2ff4494eaf362df7e..8fa7543b2d1334e042cde80350cc896cac8822b0 100644
--- a/src/libsyntax/print/pprust.rs
+++ b/src/libsyntax/print/pprust.rs
@@ -1904,8 +1904,8 @@ fn maybe_print_trailing_comment(s: ps, span: codemap::span,
     match next_comment(s) {
       Some(cmnt) => {
         if cmnt.style != comments::trailing { return; }
-        let span_line = codemap::lookup_char_pos(cm, span.hi);
-        let comment_line = codemap::lookup_char_pos(cm, cmnt.pos);
+        let span_line = cm.lookup_char_pos(span.hi);
+        let comment_line = cm.lookup_char_pos(cmnt.pos);
         let mut next = cmnt.pos + 1u;
         match next_pos { None => (), Some(p) => next = p }
         if span.hi < cmnt.pos && cmnt.pos < next &&