#2002: problems with very large (list) literals
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Reporter: Isaac Dupree | Owner: simonmar
Type: compile-time performance bug | Status: new
Priority: high | Milestone: 6.10 branch
Component: Compiler | Version: 6.8.2
Severity: normal | Resolution:
Keywords: | Difficulty: Unknown
Testcase: | Architecture: x86
Os: Linux |
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Comment (by Isaac Dupree):
There is still an issue here, with HEAD self-compiling its
parser/Lexer.{hs|x} generated by `alex` without `-g`. I have it here with
15 minutes of 2GHz CPU time and about 250MB memory used constantly
according to `top`, and no evidence of finishing.
{{{
../compiler/stage1/ghc-inplace -no-user-package-conf -H128m -O0 -fasm
-istage2/utils -istage2/basicTypes -istage2/types -istage2/hsSyn
-istage2/prelude -istage2/rename -istage2/typecheck -istage2/deSugar
-istage2/coreSyn -istage2/vectorise -istage2/specialise
-istage2/simplCore -istage2/stranal -istage2/stgSyn -istage2/simplStg
-istage2/codeGen -istage2/main -istage2/profiling -istage2/parser
-istage2/cprAnalysis -istage2/iface -istage2/cmm -istage2/nativeGen
-istage2/ghci -Wall -fno-warn-name-shadowing -fno-warn-orphans -Istage2
-package hpc -package bytestring -DGHCI -package template-haskell
-DGHCI_TABLES_NEXT_TO_CODE -I../libffi/build/include -cpp -fglasgow-exts
-fno-generics -Rghc-timing -I. -Iparser -Iutil -package unix -package
Cabal -ignore-package lang -recomp -Rghc-timing -O0 -fasm -DDEBUG -H16M
'-#include "cutils.h"' -package-name ghc-6.9.20080602 -fgenerics
-funbox-strict-fields -c parser/Lexer.hs -o stage2/parser/Lexer.o -ohi
stage2/parser/Lexer.hi
}}}
Same with -O as -O0 and -fvia-C instead of -fasm (gcc & friends never
start, presumably because GHC hasn't gotten that far)... Oh wait, -fvia-C
after 2 minutes GHC CPU, it goes into cc1 (gcc) which is taking all my RAM
memory. Hang on a moment, I'll report back when it's done or crashed, I
need to free up memory :-)
Hmm... it appears some of the settings in my mk/build.mk (-H128M) are
being overridden by compiler/Makefile (-H16M). Odd.
It's a bit tricky to reproduce, because we obviously we don't expect 6.8
and previous to succeed. I first got a working stage1, then proceeded to
modify mk/config.mk{,.in} to delete the `-g` from the `GHC_ALEX_OPTS`
line, then removed the file compiler/parser/Lexer.hs (to make sure it
would be regenerated with the new settings), then `cd compiler` and `make
stage=2`. Obviously simpler test cases could exist, but it's not simple
to see how to simplify this instance of GHC getting overwhelmed without
wrecking it
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/2002#comment:10>
GHC <http://www.haskell.org/ghc/>
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