From 2ed22ba19e6324fda81a7d638f6f3b58254f915f Mon Sep 17 00:00:00 2001
From: Matthew Pickering <matthewtpickering@gmail.com>
Date: Wed, 9 Feb 2022 13:41:41 +0000
Subject: Introduce predicate for when to enable source notes (needSourceNotes)

There were situations where we were using debugLevel == 0 as a proxy for
whether to retain source notes but -finfo-table-map also enables and
needs source notes so we should act consistently in both cases.

Ticket #20847
---
 compiler/GHC/CoreToStg/Prep.hs    | 2 +-
 compiler/GHC/Driver/Session.hs    | 6 ++++++
 compiler/GHC/HsToCore/Coverage.hs | 6 +-----
 compiler/GHC/IfaceToCore.hs       | 4 ++--
 4 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/compiler/GHC/CoreToStg/Prep.hs b/compiler/GHC/CoreToStg/Prep.hs
index ac626931cd..8a6354147c 100644
--- a/compiler/GHC/CoreToStg/Prep.hs
+++ b/compiler/GHC/CoreToStg/Prep.hs
@@ -299,7 +299,7 @@ mkDataConWorkers dflags mod_loc data_tycons
    -- If we want to generate debug info, we put a source note on the
    -- worker. This is useful, especially for heap profiling.
    tick_it name
-     | debugLevel dflags == 0                = id
+     | not (needSourceNotes dflags)           = id
      | RealSrcSpan span _ <- nameSrcSpan name = tick span
      | Just file <- ml_hs_file mod_loc       = tick (span1 file)
      | otherwise                             = tick (span1 "???")
diff --git a/compiler/GHC/Driver/Session.hs b/compiler/GHC/Driver/Session.hs
index 34d34815ce..f7d05d063d 100644
--- a/compiler/GHC/Driver/Session.hs
+++ b/compiler/GHC/Driver/Session.hs
@@ -40,6 +40,7 @@ module GHC.Driver.Session (
         lang_set,
         DynamicTooState(..), dynamicTooState, setDynamicNow,
         sccProfilingEnabled,
+        needSourceNotes,
         DynFlags(..),
         outputFile, objectSuf, ways,
         FlagSpec(..),
@@ -4841,6 +4842,11 @@ isBmi2Enabled dflags = case platformArch (targetPlatform dflags) of
 sccProfilingEnabled :: DynFlags -> Bool
 sccProfilingEnabled dflags = profileIsProfiling (targetProfile dflags)
 
+-- | Indicate whether we need to generate source notes
+needSourceNotes :: DynFlags -> Bool
+needSourceNotes dflags = debugLevel dflags > 0
+                       || gopt Opt_InfoTableMap dflags
+
 -- -----------------------------------------------------------------------------
 -- Linker/compiler information
 
diff --git a/compiler/GHC/HsToCore/Coverage.hs b/compiler/GHC/HsToCore/Coverage.hs
index 1c6ef3eafa..c59beb402c 100644
--- a/compiler/GHC/HsToCore/Coverage.hs
+++ b/compiler/GHC/HsToCore/Coverage.hs
@@ -1066,17 +1066,13 @@ data TickTransEnv = TTE { fileName     :: FastString
 data TickishType = ProfNotes | HpcTicks | Breakpoints | SourceNotes
                  deriving (Eq)
 
-sourceNotesEnabled :: DynFlags -> Bool
-sourceNotesEnabled dflags =
-  (debugLevel dflags > 0) || (gopt Opt_InfoTableMap dflags)
-
 coveragePasses :: DynFlags -> [TickishType]
 coveragePasses dflags =
     ifa (breakpointsEnabled dflags)          Breakpoints $
     ifa (gopt Opt_Hpc dflags)                HpcTicks $
     ifa (sccProfilingEnabled dflags &&
          profAuto dflags /= NoProfAuto)      ProfNotes $
-    ifa (sourceNotesEnabled dflags)          SourceNotes []
+    ifa (needSourceNotes dflags)          SourceNotes []
   where ifa f x xs | f         = x:xs
                    | otherwise = xs
 
diff --git a/compiler/GHC/IfaceToCore.hs b/compiler/GHC/IfaceToCore.hs
index 2982df668d..2e98f45745 100644
--- a/compiler/GHC/IfaceToCore.hs
+++ b/compiler/GHC/IfaceToCore.hs
@@ -1553,9 +1553,9 @@ tcIfaceExpr (IfaceLet (IfaceRec pairs) body)
 tcIfaceExpr (IfaceTick tickish expr) = do
     expr' <- tcIfaceExpr expr
     -- If debug flag is not set: Ignore source notes
-    dbgLvl <- fmap debugLevel getDynFlags
+    need_notes <- needSourceNotes <$> getDynFlags
     case tickish of
-      IfaceSource{} | dbgLvl == 0
+      IfaceSource{} | not (need_notes)
                     -> return expr'
       _otherwise    -> do
         tickish' <- tcIfaceTickish tickish
-- 
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