From 24ee75415832b05f53726f2bbdf52972b1cfb613 Mon Sep 17 00:00:00 2001 From: Pepe Iborra Date: Wed, 22 Aug 2007 09:08:44 +0000 Subject: [PATCH] A partial attempt to improve :stepover With this patch, :stepover can effectively appear to step over recursive calls and calls to locally bound functions (in a where clause). However, when we run out of ticks in the current expression, the illusion vanishes and laziness brings us to the body of the last function we "stepped over". This is not desired at all, it is potentially very confusing. As a countermeasure, when this happens :stepover emits a warning "Warning: no more breakpoints in this function body, switching to :step" --- compiler/ghci/InteractiveUI.hs | 46 +++++++++++++++++++++++++------------- compiler/main/GHC.hs | 7 +++++- compiler/main/InteractiveEval.hs | 15 +++++++++++++ 3 files changed, 51 insertions(+), 17 deletions(-) diff --git a/compiler/ghci/InteractiveUI.hs b/compiler/ghci/InteractiveUI.hs index e868d14..a926bdc 100644 --- a/compiler/ghci/InteractiveUI.hs +++ b/compiler/ghci/InteractiveUI.hs @@ -643,6 +643,21 @@ lookupCommand str = do c:_ -> return (Just c) +getCurrentBreakTick :: GHCi (Maybe BreakIndex) +getCurrentBreakTick = do + session <- getSession + resumes <- io $ GHC.getResumeContext session + case resumes of + [] -> return Nothing + (r:rs) -> do + let ix = GHC.resumeHistoryIx r + if ix == 0 + then return (GHC.breakInfo_number `fmap` GHC.resumeBreakInfo r) + else do + let hist = GHC.resumeHistory r !! (ix-1) + let tick = GHC.getHistoryTick hist + return (Just tick) + getCurrentBreakSpan :: GHCi (Maybe SrcSpan) getCurrentBreakSpan = do session <- getSession @@ -1549,29 +1564,37 @@ stepCmd expression = do runStmt expression GHC.SingleStep; return () stepOverCmd [] = do mb_span <- getCurrentBreakSpan + session <- getSession case mb_span of Nothing -> stepCmd [] - Just loc -> do - Just mod <- getCurrentBreakModule - parent <- enclosingTickSpan mod loc + Just curr_loc -> do + Just tick <- getCurrentBreakTick + Just mod <- getCurrentBreakModule + parent <- io$ GHC.findEnclosingDeclSpanByTick session mod tick allTicksRightmost <- (sortBy rightmost . map snd) `fmap` ticksIn mod parent let lastTick = null allTicksRightmost || - head allTicksRightmost == loc + head allTicksRightmost == curr_loc if not lastTick - then doContinue (`isSubspanOf` parent) GHC.SingleStep - else doContinue (const True) GHC.SingleStep + then let f t = t `isSubspanOf` parent && + (curr_loc `leftmost_largest` t == LT) + in doContinue f GHC.SingleStep + else printForUser (text "Warning: no more breakpoints in this function body, switching to :step") >> + doContinue (const True) GHC.SingleStep stepOverCmd expression = stepCmd expression {- - So, the only tricky part in stepOver is detecting that we have + The first tricky bit in stepOver is detecting that we have arrived to the last tick in an expression, in which case we must step normally to the next tick. What we do is: 1. Retrieve the enclosing expression block (with a tick) 2. Retrieve all the ticks there and sort them out by 'rightness' 3. See if the current tick turned out the first one in the list + + The second tricky bit is how to step over recursive calls. + -} --ticksIn :: Module -> SrcSpan -> GHCi [Tick] @@ -1584,15 +1607,6 @@ ticksIn mod src = do , srcSpanEnd src >= srcSpanEnd span ] -enclosingTickSpan :: Module -> SrcSpan -> GHCi SrcSpan -enclosingTickSpan mod src = do - ticks <- getTickArray mod - let line = srcSpanStartLine src - ASSERT (inRange (bounds ticks) line) do - let enclosing_spans = [ span | (_,span) <- ticks ! line - , srcSpanEnd span >= srcSpanEnd src] - return . head . sortBy leftmost_largest $ enclosing_spans - traceCmd :: String -> GHCi () traceCmd [] = doContinue (const True) GHC.RunAndLogSteps traceCmd expression = do runStmt expression GHC.RunAndLogSteps; return () diff --git a/compiler/main/GHC.hs b/compiler/main/GHC.hs index 1fc3605..4c14ff6 100644 --- a/compiler/main/GHC.hs +++ b/compiler/main/GHC.hs @@ -85,7 +85,8 @@ module GHC ( Resume(resumeStmt, resumeThreadId, resumeBreakInfo, resumeSpan, resumeHistory, resumeHistoryIx), History(historyBreakInfo, historyEnclosingDecl), - GHC.getHistorySpan, getHistoryModule, + GHC.getHistorySpan, getHistoryModule, getHistoryTick, + GHC.findEnclosingDeclSpanByTick, getResumeContext, abandon, abandonAll, InteractiveEval.back, @@ -1987,4 +1988,8 @@ findModule' hsc_env mod_name maybe_pkg = getHistorySpan :: Session -> History -> IO SrcSpan getHistorySpan sess h = withSession sess $ \hsc_env -> return$ InteractiveEval.getHistorySpan hsc_env h + +findEnclosingDeclSpanByTick :: Session -> Module -> BreakIndex -> IO SrcSpan +findEnclosingDeclSpanByTick sess m t = withSession sess $ \ hsc_env -> + return$ InteractiveEval.findEnclosingDeclSpanByTick hsc_env m t #endif diff --git a/compiler/main/InteractiveEval.hs b/compiler/main/InteractiveEval.hs index 3173278..9c28c84 100644 --- a/compiler/main/InteractiveEval.hs +++ b/compiler/main/InteractiveEval.hs @@ -13,8 +13,10 @@ module InteractiveEval ( resume, abandon, abandonAll, getResumeContext, + getHistoryTick, getHistorySpan, getHistoryModule, + findEnclosingDeclSpanByTick, back, forward, setContext, getContext, nameSetToGlobalRdrEnv, @@ -142,6 +144,9 @@ mkHistory hsc_env hval bi = let (getHistorySpan hsc_env h) in h +getHistoryTick :: History -> BreakIndex +getHistoryTick = breakInfo_number . historyBreakInfo + getHistoryModule :: History -> Module getHistoryModule = breakInfo_module . historyBreakInfo @@ -165,6 +170,16 @@ findEnclosingDecl hsc_env mod span = -- ^^ assumes md_types is sorted in decl +-- | Finds the span of the (smallest) function containing this BreakIndex +findEnclosingDeclSpanByTick :: HscEnv -> Module -> BreakIndex -> SrcSpan +findEnclosingDeclSpanByTick hsc_env mod tick = + case lookupUFM (hsc_HPT hsc_env) (moduleName mod) of + Nothing -> panic "findEnclosingDecl" + Just hmi -> let + modbreaks = md_modBreaks (hm_details hmi) + in ASSERT (inRange (bounds modBreaks) tick) + modBreaks_decls modbreaks ! tick + -- | Find the Module corresponding to a FilePath findModuleFromFile :: HscEnv -> FilePath -> Maybe Module findModuleFromFile hsc_env fp = -- 1.7.10.4