[commit: ghc] master: Tweak link order slightly to prefer user shared libs before system ones. (3d17f1f)
git at git.haskell.org
git at git.haskell.org
Mon Jan 15 19:22:34 UTC 2018
Repository : ssh://git@git.haskell.org/ghc
On branch : master
Link : http://ghc.haskell.org/trac/ghc/changeset/3d17f1f10fc00540ac052f2fd03182906aa47e35/ghc
>---------------------------------------------------------------
commit 3d17f1f10fc00540ac052f2fd03182906aa47e35
Author: Tamar Christina <tamar at zhox.com>
Date: Mon Jan 15 12:38:45 2018 -0500
Tweak link order slightly to prefer user shared libs before system ones.
We currently always prefer shared libraries before import libraries and
static libraries. This is because they're faster to load. The problem is
when shared library are installed in the Windows directory. These would
supersede any user specified ones.
This is bad because e.g. Windows now ships icuuc, but an old version.
If you try to use -licuuc then it would pick the Windows one instead of
your user specified one.
This patch slighly tweaks the ordering so user paths get prefered.
Test Plan: ./validate
Reviewers: RyanGlScott, hvr, bgamari
Reviewed By: bgamari
Subscribers: rwbarton, thomie, carter
GHC Trac Issues: #14456
Differential Revision: https://phabricator.haskell.org/D4274
>---------------------------------------------------------------
3d17f1f10fc00540ac052f2fd03182906aa47e35
compiler/ghci/Linker.hs | 48 ++++++++++++++++++++++++++++++----------
docs/users_guide/8.6.1-notes.rst | 4 ++++
2 files changed, 40 insertions(+), 12 deletions(-)
diff --git a/compiler/ghci/Linker.hs b/compiler/ghci/Linker.hs
index ecd9cbd..3775d58 100644
--- a/compiler/ghci/Linker.hs
+++ b/compiler/ghci/Linker.hs
@@ -336,6 +336,11 @@ linkCmdLineLibs' hsc_env pls =
-- See Note [Fork/Exec Windows]
gcc_paths <- getGCCPaths dflags os
+ maybePutStrLn dflags "Search directories (user):"
+ maybePutStr dflags (unlines $ map (" "++) lib_paths_base)
+ maybePutStrLn dflags "Search directories (gcc):"
+ maybePutStr dflags (unlines $ map (" "++) gcc_paths)
+
libspecs
<- mapM (locateLib hsc_env False lib_paths_base gcc_paths) minus_ls
@@ -1340,21 +1345,35 @@ locateLib :: HscEnv -> Bool -> [FilePath] -> [FilePath] -> String
locateLib hsc_env is_hs lib_dirs gcc_dirs lib
| not is_hs
-- For non-Haskell libraries (e.g. gmp, iconv):
- -- first look in library-dirs for a dynamic library (libfoo.so)
+ -- first look in library-dirs for a dynamic library (on User paths only)
+ -- (libfoo.so)
+ -- then try looking for import libraries on Windows (on User paths only)
+ -- (.dll.a, .lib)
+ -- first look in library-dirs for a dynamic library (on GCC paths only)
+ -- (libfoo.so)
+ -- then check for system dynamic libraries (e.g. kernel32.dll on windows)
+ -- then try looking for import libraries on Windows (on GCC paths only)
+ -- (.dll.a, .lib)
-- then look in library-dirs for a static library (libfoo.a)
-- then look in library-dirs and inplace GCC for a dynamic library (libfoo.so)
- -- then check for system dynamic libraries (e.g. kernel32.dll on windows)
-- then try looking for import libraries on Windows (.dll.a, .lib)
-- then look in library-dirs and inplace GCC for a static library (libfoo.a)
-- then try "gcc --print-file-name" to search gcc's search path
-- for a dynamic library (#5289)
-- otherwise, assume loadDLL can find it
--
- = findDll `orElse`
- findSysDll `orElse`
- tryImpLib `orElse`
- findArchive `orElse`
- tryGcc `orElse`
+ -- The logic is a bit complicated, but the rationale behind it is that
+ -- loading a shared library for us is O(1) while loading an archive is
+ -- O(n). Loading an import library is also O(n) so in general we prefer
+ -- shared libraries because they are simpler and faster.
+ --
+ = findDll user `orElse`
+ tryImpLib user `orElse`
+ findDll gcc `orElse`
+ findSysDll `orElse`
+ tryImpLib gcc `orElse`
+ findArchive `orElse`
+ tryGcc `orElse`
assumeDll
| loading_dynamic_hs_libs -- search for .so libraries first.
@@ -1375,12 +1394,15 @@ locateLib hsc_env is_hs lib_dirs gcc_dirs lib
where
dflags = hsc_dflags hsc_env
- dirs = lib_dirs ++ gcc_dirs
+ dirs = lib_dirs ++ gcc_dirs
+ gcc = False
+ user = True
obj_file = lib <.> "o"
dyn_obj_file = lib <.> "dyn_o"
arch_files = [ "lib" ++ lib ++ lib_tag <.> "a"
, lib <.> "a" -- native code has no lib_tag
+ , "lib" ++ lib, lib
]
lib_tag = if is_hs && loading_profiled_hs_libs then "_p" else ""
@@ -1405,7 +1427,8 @@ locateLib hsc_env is_hs lib_dirs gcc_dirs lib
findArchive = let local name = liftM (fmap Archive) $ findFile dirs name
in apply (map local arch_files)
findHSDll = liftM (fmap DLLPath) $ findFile dirs hs_dyn_lib_file
- findDll = liftM (fmap DLLPath) $ findFile dirs dyn_lib_file
+ findDll re = let dirs' = if re == user then lib_dirs else gcc_dirs
+ in liftM (fmap DLLPath) $ findFile dirs' dyn_lib_file
findSysDll = fmap (fmap $ DLL . dropExtension . takeFileName) $
findSystemLibrary hsc_env so_name
tryGcc = let search = searchForLibUsingGcc dflags
@@ -1415,10 +1438,11 @@ locateLib hsc_env is_hs lib_dirs gcc_dirs lib
gcc name = liftM (fmap Archive) $ search name lib_dirs
files = import_libs ++ arch_files
in apply $ short : full : map gcc files
- tryImpLib = case os of
+ tryImpLib re = case os of
OSMinGW32 ->
- let implib name = liftM (fmap Archive) $
- findFile dirs name
+ let dirs' = if re == user then lib_dirs else gcc_dirs
+ implib name = liftM (fmap Archive) $
+ findFile dirs' name
in apply (map implib import_libs)
_ -> return Nothing
diff --git a/docs/users_guide/8.6.1-notes.rst b/docs/users_guide/8.6.1-notes.rst
index ad5c5af..d2d5172 100644
--- a/docs/users_guide/8.6.1-notes.rst
+++ b/docs/users_guide/8.6.1-notes.rst
@@ -30,6 +30,10 @@ Compiler
Runtime system
~~~~~~~~~~~~~~
+- The GHC runtime linker now prefers user shared libraries above system ones.
+ When extra search directories are specified these are searched before anything
+ else. This fixes `iuuc` on Windows given the proper search directories (e.g
+ `-L/mingw64/lib`).
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