ErrUtils: Add timings to compiler phases

This adds timings and allocation figures to the compiler's output when
run with `-v2` in an effort to ease performance analysis.

Todo:
  * Documentation
  * Where else should we add these?
  * Perhaps we should remove some of the now-arguably-redundant
    `showPass` occurrences where they are
  * Must we force more?
  * Perhaps we should place this behind a `-ftimings` instead of `-v2`

Test Plan: `ghc -v2 Test.hs`, look at the output

Reviewers: hvr, goldfire, simonmar, austin

Reviewed By: simonmar

Subscribers: angerman, michalt, niteria, ezyang, thomie

Differential Revision: https://phabricator.haskell.org/D1959

1 files changed, 4 insertions, 3 deletions

diff --git a/compiler/main/CodeOutput.hs b/compiler/main/CodeOutput.hs
index 422fd4e35b..f172cf1259 100644
--- a/compiler/main/CodeOutput.hs
+++ b/compiler/main/CodeOutput.hs
@@ -64,9 +64,10 @@ codeOutput dflags this_mod filenm location foreign_stubs pkg_deps cmm_stream
                     then Stream.mapM do_lint cmm_stream
                     else cmm_stream
 
-              do_lint cmm = do
-                { showPass dflags "CmmLint"
-                ; case cmmLint dflags cmm of
+              do_lint cmm = withTiming (pure dflags)
+                                       (text "CmmLint"<+>brackets (ppr this_mod))
+                                       (const ()) $ do
+                { case cmmLint dflags cmm of
                         Just err -> do { log_action dflags
                                                    dflags
                                                    NoReason