[Git][ghc/ghc][wip/jeltsch/textual-bytecode-output] 3 commits: Make output of cost center literals more precise

14 Jul 2026

Wolfgang Jeltsch pushed to branch wip/jeltsch/textual-bytecode-output at Glasgow Haskell Compiler / GHC


Commits:
4c81de9a by Wolfgang Jeltsch at 2026-07-13T17:53:40+03:00
Make output of cost center literals more precise

- - - - -
5088065d by Wolfgang Jeltsch at 2026-07-13T20:09:37+03:00
Improve titles in breakpoint output

- - - - -
b9f1729b by Wolfgang Jeltsch at 2026-07-13T20:11:49+03:00
Remove offset from known-variable output

- - - - -


1 changed file:

- compiler/GHC/ByteCode/Show.hs


Changes:

=====================================
compiler/GHC/ByteCode/Show.hs
=====================================
@@ -11,7 +11,7 @@ import Control.Exception (assert)
 import Data.Eq ((==))
 import Data.Bits (FiniteBits, finiteBitSize)
 import Data.Function (($), id, (.))
-import Data.Tuple (uncurry)
+import Data.Tuple (fst, uncurry)
 import Data.Bool (Bool, otherwise, not)
 import Data.Int (Int)
 import Data.Word (Word)
@@ -191,7 +191,7 @@ pprLiteral currentModule literal = case literal of
         -> text "foreign function" <+>
            quotes (pprFFIInfo ffiInfo)
     BCONPtrCostCentre breakpointID
-        -> text "cost center" <+>
+        -> text "cost center of breakpoint" <+>
            pprInternalBreakpointID currentModule breakpointID
 
 -- | […]
@@ -285,35 +285,35 @@ pprBreakpoints currentModule
 pprBreakpointsData :: Module -> InternalModBreaks -> SDoc
 pprBreakpointsData currentModule InternalModBreaks {..}
     = vcat [
-               pprBreakpointsInSource currentModule   $ imodBreaks_modBreaks,
-               pprBreakpointsInByteCode currentModule $ imodBreaks_breakInfo
+               pprSourceBreakpoints currentModule   $ imodBreaks_modBreaks,
+               pprByteCodeBreakpoints currentModule $ imodBreaks_breakInfo
            ]
 
 -- | […]
-pprBreakpointsInSource :: Module -> ModBreaks -> SDoc
-pprBreakpointsInSource currentModule ModBreaks {..}
-    = entry (text "breakpoints in source")                      $
+pprSourceBreakpoints :: Module -> ModBreaks -> SDoc
+pprSourceBreakpoints currentModule ModBreaks {..}
+    = entry (text "source breakpoints")                         $
       assert (modBreaks_module == currentModule)                $
       assert (bounds modBreaks_locs_ == bounds modBreaks_decls) $
       assert (bounds modBreaks_locs_ == bounds modBreaks_vars)  $
       vcatOrNone                                                $
-      zipWith4 pprBreakpointInSource (indices modBreaks_locs_)
-                                     (elems modBreaks_locs_)
-                                     (elems modBreaks_decls)
-                                     (elems modBreaks_vars)
+      zipWith4 pprSourceBreakpoint (indices modBreaks_locs_)
+                                   (elems modBreaks_locs_)
+                                   (elems modBreaks_decls)
+                                   (elems modBreaks_vars)
       -- The cost center infos in `modBreaks_ccs`, when present, just contain
       -- textual representations of the declaration paths in `modBreaks_decls`
       -- and the source spans in `modBreaks_locs_` and are therefore never
       -- shown.
 
 -- | […]
-pprBreakpointInSource :: BreakTickIndex
-                      -> BinSrcSpan
-                      -> [String]
-                      -> [OccName]
-                      -> SDoc
-pprBreakpointInSource ix srcSpan declarationPath freeVars
-    = entry (text "breakpoint" <+> ppr ix) $
+pprSourceBreakpoint :: BreakTickIndex
+                    -> BinSrcSpan
+                    -> [String]
+                    -> [OccName]
+                    -> SDoc
+pprSourceBreakpoint ix srcSpan declarationPath freeVars
+    = entry (text "source breakpoint" <+> ppr ix) $
       vcat [
                pprSrcSpan         $ srcSpan,
                pprDeclarationPath $ declarationPath,
@@ -333,22 +333,22 @@ pprFreeVariables :: [OccName] -> SDoc
 pprFreeVariables = entry (text "free variables") . vcatOrNone . map ppr
 
 -- | […]
-pprBreakpointsInByteCode :: Module -> IntMap CgBreakInfo -> SDoc
-pprBreakpointsInByteCode currentModule
-    = entry (text "breakpoints in bytecode")                .
-      vcatOrNone                                            .
-      map (uncurry (pprBreakpointInByteCode currentModule)) .
+pprByteCodeBreakpoints :: Module -> IntMap CgBreakInfo -> SDoc
+pprByteCodeBreakpoints currentModule
+    = entry (text "bytecode breakpoints")                 .
+      vcatOrNone                                          .
+      map (uncurry (pprByteCodeBreakpoint currentModule)) .
       IntMap.toList
 
 -- | […]
-pprBreakpointInByteCode :: Module -> Int -> CgBreakInfo -> SDoc
-pprBreakpointInByteCode currentModule ix CgBreakInfo {..}
-    = entry (text "breakpoint" <+> ppr ix) $
+pprByteCodeBreakpoint :: Module -> Int -> CgBreakInfo -> SDoc
+pprByteCodeBreakpoint currentModule ix CgBreakInfo {..}
+    = entry (text "bytecode breakpoint" <+> ppr ix) $
       vcat [
-               pprType                 $ cgb_resty,
-               pprTypeVariables        $ cgb_tyvars,
-               pprVariables            $ cgb_vars,
-               pprOrigin currentModule $ cgb_tick_id
+               pprType                                        $ cgb_resty,
+               pprTypeVariables                               $ cgb_tyvars,
+               pprVariables                                   $ cgb_vars,
+               pprCorrespondingSourceBreakpoint currentModule $ cgb_tick_id
            ]
     -- That the 'cgb_resty' field holds the type of the breakpoint is apparent
     -- from the fact that this field is set by
@@ -377,15 +377,7 @@ pprVariables = entry (text "variables") . vcatOrNone . map pprVariable
 
 -- | […]
 pprVariable :: Maybe (IfaceIdBndr, Word) -> SDoc
-pprVariable = maybe (text "<unknown>") (uncurry pprKnownVariable)
-
-pprKnownVariable :: IfaceIdBndr -> Word -> SDoc
-pprKnownVariable binder offset = pprVariableBinder binder <+>
-                                 text "@"                 <+>
-                                 ppr offset

--- That the second argument is an offset is apparent from the use of the
--- identifier @offset@ in the implementation of
--- 'GHC.StgToByteCode.dehydrateCgBreakInfo'.
+pprVariable = maybe (text "<unknown>") (pprVariableBinder . fst)
 
 -- | […]
 pprVariableBinder :: IfaceIdBndr -> SDoc
@@ -393,10 +385,13 @@ pprVariableBinder (multiplicity, name, type_)
     = text "%" <> ppr multiplicity <+>
       ppr name <+> text "::" <+> ppr type_
 
-pprOrigin :: Module -> Either InternalBreakLoc BreakpointId -> SDoc
-pprOrigin currentModule = entry (text "origin")         .
-                          pprBreakpointID currentModule .
-                          either internalBreakLoc id
+pprCorrespondingSourceBreakpoint :: Module
+                                 -> Either InternalBreakLoc BreakpointId
+                                 -> SDoc
+pprCorrespondingSourceBreakpoint currentModule
+    = entry (text "corresponding source breakpoint") .
+      pprBreakpointID currentModule                  .
+      either internalBreakLoc id
 
 -- | […] [analogous to 'pprInternalBreakpointID' but the meaning of the index is different]
 pprBreakpointID :: Module -> BreakpointId -> SDoc



View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/c461ef90e2cd36eb8c28b0de196b38f...

-- 
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/c461ef90e2cd36eb8c28b0de196b38f...
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Wolfgang Jeltsch (＠jeltsch)

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