Hi again,
Sorry for the late reply. Hopefully we can still fix this.
On Sat, Jun 08, 2019 at 10:35PM, Paul Gevers wrote:
> I *think* we could also binNMU in experimental. And we could just try a
> couple of packages that you know that won't work right now.
I tried to find a package which has as fewer Haskell dependencies as
possible and found happy, which build-depends only on ghc.
The current version of happy on ARMEL is broken:
objdump -d /usr/bin/happy |grep uxth
15c0ac: e6ff1072 uxth r1, r2
15c184: e6ff2073 uxth r2, r3
1ab0ac: e6ff107e uxth r1, lr
1ab0e8: e6ff1073 uxth r1, r3
1ab158: e6ff107e uxth r1, lr
1ab19c: e6ff1073 uxth r1, r3
...
(notice that the UXTH command is supported only on ARMv6 or later [1])
[1] http://infocenter.arm.com/help/topic/com.arm.doc.dui0489i/CIHHJCFE.html
and I can trigger the above instruction with:
$ gdb -q -ex 'b *(0x1ab0ac)' -ex 'run' -ex 'x/i $pc' -ex 'quit' --args
happy example.y
Reading symbols from happy...(no debugging symbols found)...done.
Breakpoint 1 at 0x1ab0ac
Starting program: /usr/bin/happy example.y
[Thread debugging using libthread_db enabled]
Using host libthread_db library
"/lib/arm-linux-gnueabi/libthread_db.so.1".
Breakpoint 1, 0x001ab0ac in ?? ()
=> 0x1ab0ac: uxth r1, lr
A debugging session is active.
Inferior 1 [process 29559] will be killed.
Quit anyway? (y or n) y
As input, I used the attached example taken from [2].
[2] https://www.haskell.org/happy/doc/html/sec-using.html
I then rebuild ghc with the proposed patch on abel, and used that to
rebuild happy. The final binary does not contain the UXTH instruction.
I have uploaded both ghc and happy here, in case you need Emanuele to
verify that the current version of happy fails, whereas the new one
works:
https://www.iliastsi.net/ghc/ghc_8.4.4+dfsg1-2+armel0_armel.deb
sha256: 5d8dae44d79545aeee34755baa6c51ffe80db8309051978aaa9ac8857d6efde9
https://www.iliastsi.net/ghc/ghc-doc_8.4.4+dfsg1-2+armel0_all.deb
sha256: bffaf0957deb767d75e251f92dd8a59c6277c5b986241219fbb26ea3400284fa
https://www.iliastsi.net/ghc/ghc-prof_8.4.4+dfsg1-2+armel0_armel.deb
sha256: 8fde49d87ad410ae5fec77ac89af4da11f4a2dd0924f0085a2f5f9c6e93fc09c
https://www.iliastsi.net/ghc/happy_1.19.9-6+armel0_armel.deb
sha256: c560c02e7369c08de18f7151bcb53245a1c7f4ab83e9c07265beef7ca0e24921
So, it seems that the proposed patch does indeed resolve the issue.
Unfortunately, I cannot provide any guarantee that it will not introduce
any bugs that weren't there before, but I believe the only way to find
out is to upload a fixed version of GHC on unstable and schedule the
required binNMUs. If all of them succeed, we can then unblock them.
--
Ilias
{
module Main where
}
%name calc
%tokentype { Token }
%error { parseError }
%token
let { TokenLet }
in { TokenIn }
int { TokenInt $$ }
var { TokenVar $$ }
'=' { TokenEq }
'+' { TokenPlus }
'-' { TokenMinus }
'*' { TokenTimes }
'/' { TokenDiv }
'(' { TokenOB }
')' { TokenCB }
%%
Exp : let var '=' Exp in Exp { Let $2 $4 $6 }
| Exp1 { Exp1 $1 }
Exp1 : Exp1 '+' Term { Plus $1 $3 }
| Exp1 '-' Term { Minus $1 $3 }
| Term { Term $1 }
Term : Term '*' Factor { Times $1 $3 }
| Term '/' Factor { Div $1 $3 }
| Factor { Factor $1 }
Factor
: int { Int $1 }
| var { Var $1 }
| '(' Exp ')' { Brack $2 }
{
parseError :: [Token] -> a
parseError _ = error "Parse error"
data Exp
= Let String Exp Exp
| Exp1 Exp1
deriving Show
data Exp1
= Plus Exp1 Term
| Minus Exp1 Term
| Term Term
deriving Show
data Term
= Times Term Factor
| Div Term Factor
| Factor Factor
deriving Show
data Factor
= Int Int
| Var String
| Brack Exp
deriving Show
data Token
= TokenLet
| TokenIn
| TokenInt Int
| TokenVar String
| TokenEq
| TokenPlus
| TokenMinus
| TokenTimes
| TokenDiv
| TokenOB
| TokenCB
deriving Show
lexer :: String -> [Token]
lexer [] = []
lexer (c:cs)
| isSpace c = lexer cs
| isAlpha c = lexVar (c:cs)
| isDigit c = lexNum (c:cs)
lexer ('=':cs) = TokenEq : lexer cs
lexer ('+':cs) = TokenPlus : lexer cs
lexer ('-':cs) = TokenMinus : lexer cs
lexer ('*':cs) = TokenTimes : lexer cs
lexer ('/':cs) = TokenDiv : lexer cs
lexer ('(':cs) = TokenOB : lexer cs
lexer (')':cs) = TokenCB : lexer cs
lexNum cs = TokenInt (read num) : lexer rest
where (num,rest) = span isDigit cs
lexVar cs =
case span isAlpha cs of
("let",rest) -> TokenLet : lexer rest
("in",rest) -> TokenIn : lexer rest
(var,rest) -> TokenVar var : lexer rest
main = getContents >>= print . calc . lexer
}
