Marge Bot pushed to branch wip/marge_bot_batch_merge_job at Glasgow Haskell Compiler / GHC

Commits:

• b418408b
  by Irene Knapp at 2025-09-25T09:47:54-04:00

  Document etymology of "bind" as the name for `>>=`
  
  It took me twenty years of contemplation to realize why it's called that.
  I therefore feel that it may not be obvious to beginners.
  

• e9c5e46f
  by Brandon Chinn at 2025-09-25T09:48:36-04:00

  Fix tabs in string gaps (#26415)
  
  Tabs in string gaps were broken in bb030d0d because previously, string gaps were manually parsed, but now it's lexed by the usual Alex grammar and post-processed after successful lexing.
  
  It broke because of a discrepancy between GHC's lexer grammar and the Haskell Report. The Haskell Report includes tabs in whitechar:
  
  whitechar  →  newline | vertab | space | tab | uniWhite
  
  $whitechar used to include tabs until 18 years ago, when it was removed in order to exclude tabs from $white_no_nl in order to warn on tabs: 6e202120. In this MR, I'm adding \t back into $whitechar, and explicitly excluding \t from the $white_no_nl+ rule ignoring all whitespace in source code, which more accurately colocates the "ignore all whitespace except tabs, which is handled in the next line" logic.
  
  As a side effect of this MR, tabs are now allowed in pragmas; currently, a pragma written as {-# \t LANGUAGE ... #-} is interpreted as the tab character being the pragma name, and GHC warns "Unrecognized pragma". With this change, tabs are ignored as whitespace, which more closely matches the Report anyway.
  

• 8bf5b309
  by Cheng Shao at 2025-09-25T09:49:18-04:00

  wasm: remove the --no-turbo-fast-api-calls hack from dynamic linker shebang
  
  This patch removes the `--no-turbo-fast-api-calls` hack from the dyld
  script shebang; it was used to workaround v8 fast call coredumps in
  nodejs and no longer needed, and comes with a performance penalty,
  hence the removal.
  

• 35622b41
  by Sylvain Henry at 2025-09-26T05:25:33-04:00

  Revert "Add necessary flag for js linking"
  
  This reverts commit 84f68e2231b2eddb2e1dc4e90af394ef0f2e803f.
  
  This commit didn't have the expected effect. See discussion in #26290.
  Instead we export HEAP8 and HEAPU8 from rts/js/mem.js
  

• 179265cd
  by Sylvain Henry at 2025-09-26T05:25:33-04:00

  JS: export HEAPU8 (#26290)
  
  This is now required by newer Emscripten versions.
  

• ad319868
  by Andreas Klebinger at 2025-09-26T05:25:34-04:00

  sizeExpr: Improve Tick handling.
  
  When determining if we scrutinize a function argument we
  now properly look through ticks. Fixes #26444.
  

12 changed files:

• compiler/GHC/Core/Unfold.hs
• compiler/GHC/Parser/Lexer.x
• compiler/GHC/Parser/Lexer/String.x
• libraries/ghc-internal/src/GHC/Internal/Base.hs
• m4/fptools_set_c_ld_flags.m4
• rts/js/mem.js
• testsuite/driver/testlib.py
• + testsuite/tests/parser/should_run/T26415.hs
• + testsuite/tests/parser/should_run/T26415.stdout
• testsuite/tests/parser/should_run/all.T
• utils/ghc-toolchain/src/GHC/Toolchain/Tools/Link.hs
• utils/jsffi/dyld.mjs

Changes:

         where

           is_top_arg (Var v) | v `elem` top_args = Just v

           is_top_arg (Cast e _) = is_top_arg e

+          is_top_arg (Tick _t e) = is_top_arg e

           is_top_arg _ = Nothing

       where

 $unispace    = \x05 -- Trick Alex into handling Unicode. See Note [Unicode in Alex].

 $nl          = [\n\r\f]

 $space       = [\ $unispace]

-$whitechar   = [$nl \v $space]

+$whitechar   = [$nl \t \v $space]

 $white_no_nl = $whitechar # \n -- TODO #8424

 $tab         = \t

 -- Alex "Rules"

 -- everywhere: skip whitespace

-$white_no_nl+ ;

+($white_no_nl # \t)+ ;

 $tab          { warnTab }

 -- Everywhere: deal with nested comments.  We explicitly rule out

 $unispace    = \x05 -- Trick Alex into handling Unicode. See Note [Unicode in Alex].

 $nl          = [\n\r\f]

 $space       = [\ $unispace]

-$whitechar   = [$nl \v $space]

+$whitechar   = [$nl \t \v $space]

 $tab         = \t

 $ascdigit  = 0-9

     --    bs a

     -- @

     --

-    -- An alternative name for this function is \'bind\', but some people

-    -- may refer to it as \'flatMap\', which results from it being equivalent

-    -- to

+    -- An alternative name for this function is \'bind\', because it

+    -- is used to introduce bindings in monadic contexts, but some people may

+    -- refer to it as \'flatMap\', which results from it being equivalent to

     --

     -- @\\x f -> 'join' ('fmap' f x) :: Monad m => m a -> (a -> m b) -> m b@

     --

         $2="$$2 -mcmodel=medium"

         ;;

-    javascript*)

-        $3="$$3 -sEXPORTED_RUNTIME_METHODS=HEAP8,HEAPU8"

-

     esac

     AC_MSG_RESULT([done])

 //#OPTIONS:CPP

-//#OPTIONS:EMCC:EXPORTED_RUNTIME_METHODS=addFunction,removeFunction,getEmptyTableSlot,HEAP8

+//#OPTIONS:EMCC:EXPORTED_RUNTIME_METHODS=addFunction,removeFunction,getEmptyTableSlot,HEAP8,HEAPU8

 // #define GHCJS_TRACE_META 1

     # Emscripten displays cache info and old emcc doesn't support EMCC_LOGGING=0

     s = re.sub('cache:INFO: .*\n', '', s)

     # Old emcc warns when we export HEAP8 but new one requires it (see #26290)

-    s = s.replace('warning: invalid item in EXPORTED_RUNTIME_METHODS: HEAP8\nemcc: warning: warnings in JS library compilation [-Wjs-compiler]\n','')

+    s = s.replace('warning: invalid item in EXPORTED_RUNTIME_METHODS: HEAP8\nwarning: invalid item in EXPORTED_RUNTIME_METHODS: HEAPU8\nemcc: warning: warnings in JS library compilation [-Wjs-compiler]\n','')

     return s

+{-# LANGUAGE MultilineStrings #-}

+

+main :: IO ()

+main = do

+  -- The below strings contain the characters ['\\', '\t', '\\']

+  print "\	\"

+  print """\	\"""

+""

+""

 test('RecordDotSyntax5', normal, compile_and_run, [''])

 test('ListTuplePunsConstraints', extra_files(['ListTuplePunsConstraints.hs']), ghci_script, ['ListTuplePunsConstraints.script'])

 test('T25937', normal, compile_and_run, [''])

+test('T26415', normal, compile_and_run, [''])

 # Multiline strings

 test('MultilineStrings', normal, compile_and_run, [''])

     ArchOS ArchPPC OSAIX ->

       -- We need `-D_THREAD_SAFE` to unlock the thread-local `errno`.

       return $ ccLink2 & over _prgFlags (++["-D_THREAD_SAFE","-Wl,-bnotextro"])

-    ArchOS ArchJavaScript OSGhcjs ->

-      -- Since https://github.com/emscripten-core/emscripten/blob/main/ChangeLog.md#407---041525

-      -- the emcc linker does not export the HEAP8 memory view which is used by the js RTS by default anymore.

-      return $ ccLink2 & _prgFlags %++ "-sEXPORTED_RUNTIME_METHODS=HEAP8,HEAPU8"

     _ ->

       return ccLink2

-#!/usr/bin/env -S node --disable-warning=ExperimentalWarning --max-old-space-size=65536 --no-turbo-fast-api-calls --wasm-lazy-validation

+#!/usr/bin/env -S node --disable-warning=ExperimentalWarning --max-old-space-size=65536 --wasm-lazy-validation

 // Note [The Wasm Dynamic Linker]

 // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~