id,summary,reporter,owner,description,type,status,priority,milestone,component,version,resolution,keywords,cc,os,architecture,failure,difficulty,testcase,blockedby,blocking,related
2297,Profiler is inconsistent about biography for GHC's heap,igloo,,"My slightly modified `rnBind` has this clause (`i` is an `Int`):
{{{
rnBind sig_fn
       trim
       i
       (L loc (FunBind { fun_id = name, 
                         fun_infix = inf, 
                         fun_matches = matches,
                         -- no pattern FVs
                         bind_fvs = _
                       }))
       -- invariant: no free vars here when it's a FunBind
  = i `seq` setSrcSpan loc $
    do  { let plain_name = unLoc name

    ; (matches', fvs) <- bindSigTyVarsFV (sig_fn plain_name) $
                -- bindSigTyVars tests for Opt_ScopedTyVars
                 rnMatchGroup (FunRhs plain_name inf) matches

    ; checkPrecMatch inf plain_name matches'

    ; return
        (L loc (trace (""Using FunBind for "" ++ show i)
                (FunBind { fun_id = name, 
                                  fun_infix = inf, 
                                  fun_matches = matches',
                     bind_fvs = trim fvs, 
                                  fun_co_fn = idHsWrapper, 
                                  fun_tick = Nothing })),
          [plain_name],
          fvs)
      }
}}}
If I comment out the trace and run
{{{
ghc --make J -fforce-recomp +RTS -p -hcrnBind -hyHsBindLR -hb
}}}
then I get `notrace.png`, all VOID. However, with the trace I get `trace.png`, LAG turning into DRAG. The two graphs are also a slightly different shape, which is curious.

Also attached is the core for with and without the tracing. I think the only interesting difference is
{{{
-      a30_ [ALWAYS Just L] :: NameSet.FreeVars
+      a30_ [ALWAYS Just L] :: HsBinds.HsBindLR Name.Name Name.Name
       [Str: DmdType]
-      a30_ = w1_ ww3_ } in
-    let {
-      a31_ :: HsBinds.HsWrapper
-      []
-      a31_ =
-        __scc {rnBind ghc-6.9.20080517:RnBinds !}
-        __scc {idHsWrapper ghc-6.9.20080517:HsBinds} HsBinds.WpHole } in
-    let {
-      a32_ :: HsBinds.HsWrapper
-      []
-      a32_ =
-        __scc {rnBind ghc-6.9.20080517:RnBinds !}
-        __scc {idHsWrapper ghc-6.9.20080517:HsBinds} HsBinds.WpHole } in
-    let {
-      a33_ :: HsBinds.HsBindLR Name.Name Name.Name
-      [Str: DmdType]
-      a33_ =
-        HsBinds.FunBind
-          @ Name.Name
-          @ Name.Name
-          name_
-          inf_
-          ww2_
-          a32_
-          a30_
-          (Data.Maybe.Nothing @ (GHC.Base.Int, [Name.Name])) } in
+      a30_ =
+        Debug.Trace.trace
+          @ (HsBinds.HsBindLR Name.Name Name.Name)
+          lvl45_
+          (HsBinds.FunBind
+             @ Name.Name
+             @ Name.Name
+             name_
+             inf_
+             ww2_
+             (__scc {rnBind ghc-6.9.20080517:RnBinds !}
+              __scc {idHsWrapper ghc-6.9.20080517:HsBinds} HsBinds.WpHole)
+             (w1_ ww3_)
+             (Data.Maybe.Nothing @ (GHC.Base.Int, [Name.Name]))) } in
}}}
",bug,closed,normal,6.10.2,Profiling,6.9,fixed,,,Unknown/Multiple,Unknown/Multiple,,Unknown,,,,