#5292: libHSghc exports more symbols than Windows can handle
---------------------------------+------------------------------------------
Reporter: batterseapower | Owner:
Type: bug | Status: new
Priority: normal | Milestone: 7.4.1
Component: Compiler | Version: 7.0.3
Keywords: | Testcase:
Blockedby: | Difficulty:
Os: Windows | Blocking:
Architecture: Unknown/Multiple | Failure: Runtime crash
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Comment(by batterseapower@…):
commit 0e765db44229aed591f9f423ef909b5f76696de0
{{{
Author: Max Bolingbroke <[email protected]>
Date: Fri Jul 29 12:05:46 2011 +0100
Add CoreMonad.reinitializeGlobals so plugins can work around linker
issues
When a plugin is loaded, it currently gets linked against a *newly
loaded* copy
of the GHC package. This would not be a problem, except that the new
copy has its
own mutable state that is not shared with that state that has already
been initialized by
the original GHC package.
This leads to loaded plugins calling GHC code which pokes the static
flags,
and then dying with a panic because the static flags *it* sees are
uninitialized.
There are two possible solutions:
1. Export the symbols from the GHC executable from the GHC library
and link
against this existing copy rather than a new copy of the GHC
library
2. Carefully ensure that the global state in the two copies of the
GHC
library matches
I tried 1. and it *almost* works (and speeds up plugin load times!)
except
on Windows. On Windows the GHC library tends to export more than 65536
symbols
(see #5292) which overflows the limit of what we can export from the
EXE and
causes breakage.
(Note that if the GHC exeecutable was dynamically linked this wouldn't
be a problem,
because we could share the GHC library it links to.)
We are going to try 2. instead. Unfortunately, this means that every
plugin
will have to say `reinitializeGlobals` before it does anything, but
never mind.
I've threaded the cr_globals through CoreM rather than giving them as
an
argument to the plugin function so that we can turn this function into
(return ()) without breaking any plugins when we eventually get 1.
working.
compiler/HsVersions.h | 14 ++++----
compiler/ghci/Linker.lhs | 56 ++++++++++++++++++++++-------
compiler/main/StaticFlags.hs | 24 ++++++++++++-
compiler/simplCore/CoreMonad.lhs | 72
+++++++++++++++++++++++++++++++++++---
compiler/utils/Util.lhs | 10 ++----
5 files changed, 142 insertions(+), 34 deletions(-)
}}}
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/5292#comment:6>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
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