configure.ac

@@ -922,17 +922,6 @@ AC_CHECK_DECLS([program_invocation_short_name], , ,
 [#define _GNU_SOURCE 1
 #include <errno.h>])
 
-dnl ** check for mingwex library
-AC_CHECK_LIB(
-  [mingwex],
-  [closedir],
-  [AC_SUBST([HaveLibMingwEx],[YES])] [AC_SUBST([CabalMingwex],[True])],
-  [AC_SUBST([HaveLibMingwEx],[NO])] [AC_SUBST([CabalMingwex],[False])])
-
-if test $HaveLibMingwEx = YES ; then
-  AC_DEFINE([HAVE_MINGWEX], [1], [Define to 1 if you have the mingwex library.])
-fi
-
 dnl ** check for math library
 dnl    Keep that check as early as possible.
 dnl    as we need to know whether we need libm

hadrian/cfg/system.config.in

@@ -204,7 +204,6 @@ libnuma-lib-dir       = @LibNumaLibDir@
 
 use-lib-dw        = @UseLibdw@
 use-lib-numa      = @UseLibNuma@
-use-lib-mingw-ex  = @HaveLibMingwEx@
 use-lib-m         = @UseLibm@
 use-lib-rt        = @UseLibrt@
 use-lib-dl        = @UseLibdl@

hadrian/src/Oracles/Flag.hs

@@ -33,7 +33,6 @@ data Flag = ArSupportsAtFile
           | UseLibffiForAdjustors
           | UseLibdw
           | UseLibnuma
-          | UseLibmingwex
           | UseLibm
           | UseLibrt
           | UseLibdl
@@ -63,7 +62,6 @@ flag f = do
             UseLibffiForAdjustors -> "use-libffi-for-adjustors"
             UseLibdw             -> "use-lib-dw"
             UseLibnuma           -> "use-lib-numa"
-            UseLibmingwex        -> "use-lib-mingw-ex"
             UseLibm              -> "use-lib-m"
             UseLibrt             -> "use-lib-rt"
             UseLibdl             -> "use-lib-dl"

hadrian/src/Rules/Generate.hs

@@ -266,7 +266,6 @@ templateRules = do
     target_word_size       <- settingWord TargetWordSize
     lib_dw                 <- flag UseLibdw
     lib_numa               <- flag UseLibnuma
-    lib_mingwex            <- flag UseLibmingwex
     lib_m                  <- flag UseLibm
     lib_rt                 <- flag UseLibrt
     lib_dl                 <- flag UseLibdl
@@ -283,7 +282,6 @@ templateRules = do
         subst = replace "@ProjectVersion@" project_version
                 . replace "@ProjectVersionMunged@" project_version_munged
                 . replace "@Cabal64bit@" (cabal_bool (target_word_size == 8))
-                . replace "@CabalMingwex@" (cabal_bool lib_mingwex)
                 . replace "@CabalHaveLibdw@" (cabal_bool lib_dw)
                 . replace "@CabalHaveLibm@" (cabal_bool lib_m)
                 . replace "@CabalHaveLibrt@" (cabal_bool lib_rt)

hadrian/src/Settings/Packages.hs

@@ -404,8 +404,7 @@ rtsPackageArgs = package rts ? do
         , builder HsCpp ? pure
           [ "-DTOP="             ++ show top ]
 
-        , builder HsCpp ? flag UseLibdw ? arg "-DUSE_LIBDW"
-        , builder HsCpp ? flag UseLibmingwex ? arg "-DHAVE_LIBMINGWEX" ]
+        , builder HsCpp ? flag UseLibdw ? arg "-DUSE_LIBDW" ]
 
 -- Compile various performance-critical pieces *without* -fPIC -dynamic
 -- even when building a shared library.  If we don't do this, then the

libraries/base/System/Posix/Internals.hs

@@ -452,7 +452,6 @@ foreign import ccall unsafe "HsBase.h __hscore_fstat"
 
 foreign import ccall unsafe "HsBase.h __hscore_lstat"
    lstat :: CFilePath -> Ptr CStat -> IO CInt
-
 #endif
 
 #if defined(js_HOST_ARCH)
@@ -592,109 +591,95 @@ foreign import javascript unsafe "(($1,$2,$3_1,$3_2) => { return h$base_c_fcntl_
 
 #else
 
-{- Note: Win32 POSIX functions
-Functions that are not part of the POSIX standards were
-at some point deprecated by Microsoft. This deprecation
-was performed by renaming the functions according to the
-C++ ABI Section 17.6.4.3.2b. This was done to free up the
-namespace of normal Windows programs since Windows isn't
-POSIX compliant anyway.
+#if defined(mingw32_HOST_OS)
+-- See Note [Windows types]
+foreign import capi unsafe "HsBase.h _read"
+   c_read :: CInt -> Ptr Word8 -> CUInt -> IO CInt
 
-These were working before since the RTS was re-exporting
-these symbols under the undeprecated names. This is no longer
-being done. See #11223
+-- See Note [Windows types]
+foreign import capi safe "HsBase.h _read"
+   c_safe_read :: CInt -> Ptr Word8 -> CUInt -> IO CInt
 
-See https://msdn.microsoft.com/en-us/library/ms235384.aspx
-for more.
+foreign import ccall unsafe "HsBase.h _umask"
+   c_umask :: CMode -> IO CMode
 
-However since we can't hope to get people to support Windows
-packages we should support the deprecated names. See #12497
--}
-foreign import capi unsafe "unistd.h lseek"
-   c_lseek :: CInt -> COff -> CInt -> IO COff
+-- See Note [Windows types]
+foreign import capi unsafe "HsBase.h _write"
+   c_write :: CInt -> Ptr Word8 -> CUInt -> IO CInt
 
-foreign import ccall unsafe "HsBase.h access"
+-- See Note [Windows types]
+foreign import capi safe "HsBase.h _write"
+   c_safe_write :: CInt -> Ptr Word8 -> CUInt -> IO CInt
+
+foreign import ccall unsafe "HsBase.h _pipe"
+   c_pipe :: Ptr CInt -> IO CInt
+
+foreign import capi unsafe "HsBase.h _lseeki64"
+   c_lseek :: CInt -> Int64 -> CInt -> IO Int64
+
+foreign import capi unsafe "HsBase.h _access"
    c_access :: CString -> CInt -> IO CInt
 
 #if !defined(HAVE_CHMOD)
 c_chmod :: CString -> CMode -> IO CInt
-c_chmod _ _ = ioError (ioeSetLocation unsupportedOperation "chmod")
+c_chmod _ _ = ioError (ioeSetLocation unsupportedOperation "_chmod")
 #else
-foreign import ccall unsafe "HsBase.h chmod"
+foreign import ccall unsafe "HsBase.h _chmod"
    c_chmod :: CString -> CMode -> IO CInt
 #endif
 
-foreign import ccall unsafe "HsBase.h close"
+foreign import capi unsafe "HsBase.h _close"
    c_close :: CInt -> IO CInt
 
-foreign import ccall unsafe "HsBase.h creat"
+foreign import capi unsafe "HsBase.h _creat"
    c_creat :: CString -> CMode -> IO CInt
 
 #if !defined(HAVE_DUP)
 c_dup :: CInt -> IO CInt
-c_dup _ = ioError (ioeSetLocation unsupportedOperation "dup")
+c_dup _ = ioError (ioeSetLocation unsupportedOperation "_dup")
 
 c_dup2 :: CInt -> CInt -> IO CInt
-c_dup2 _ _ = ioError (ioeSetLocation unsupportedOperation "dup2")
+c_dup2 _ _ = ioError (ioeSetLocation unsupportedOperation "_dup2")
 #else
-foreign import ccall unsafe "HsBase.h dup"
+foreign import ccall unsafe "HsBase.h _dup"
    c_dup :: CInt -> IO CInt
 
-foreign import ccall unsafe "HsBase.h dup2"
+foreign import ccall unsafe "HsBase.h _dup2"
    c_dup2 :: CInt -> CInt -> IO CInt
 #endif
 
-foreign import ccall unsafe "HsBase.h isatty"
+foreign import capi unsafe "HsBase.h _isatty"
    c_isatty :: CInt -> IO CInt
 
-#if defined(mingw32_HOST_OS)
--- See Note: Windows types
-foreign import capi unsafe "HsBase.h _read"
-   c_read :: CInt -> Ptr Word8 -> CUInt -> IO CInt
-
--- See Note: Windows types
-foreign import capi safe "HsBase.h _read"
-   c_safe_read :: CInt -> Ptr Word8 -> CUInt -> IO CInt
-
-foreign import ccall unsafe "HsBase.h _umask"
-   c_umask :: CMode -> IO CMode
-
--- See Note: Windows types
-foreign import capi unsafe "HsBase.h _write"
-   c_write :: CInt -> Ptr Word8 -> CUInt -> IO CInt
+foreign import capi unsafe "HsBase.h _unlink"
+   c_unlink :: CString -> IO CInt
 
--- See Note: Windows types
-foreign import capi safe "HsBase.h _write"
-   c_safe_write :: CInt -> Ptr Word8 -> CUInt -> IO CInt
+foreign import capi unsafe "HsBase.h _utime"
+   c_utime :: CString -> Ptr CUtimbuf -> IO CInt
 
-foreign import ccall unsafe "HsBase.h _pipe"
-   c_pipe :: Ptr CInt -> IO CInt
+foreign import capi unsafe "HsBase.h _getpid"
+   c_getpid :: IO CPid
 #else
 -- We use CAPI as on some OSs (eg. Linux) this is wrapped by a macro
 -- which redirects to the 64-bit-off_t versions when large file
 -- support is enabled.
 
--- See Note: Windows types
+-- See Note [Windows types]
 foreign import capi unsafe "HsBase.h read"
    c_read :: CInt -> Ptr Word8 -> CSize -> IO CSsize
 
--- See Note: Windows types
+-- See Note [Windows types]
 foreign import capi safe "HsBase.h read"
    c_safe_read :: CInt -> Ptr Word8 -> CSize -> IO CSsize
 
-#if defined(HAVE_UMASK)
 foreign import ccall unsafe "HsBase.h umask"
    c_umask :: CMode -> IO CMode
-#else
-c_umask :: CMode -> IO CMode
-c_umask _ = ioError (ioeSetLocation unsupportedOperation "umask")
-#endif
 
--- See Note: Windows types
+-- See Note [Windows types]
 foreign import capi unsafe "HsBase.h write"
    c_write :: CInt -> Ptr Word8 -> CSize -> IO CSsize
 
--- See Note: Windows types
+-- See Note [Windows types]
 foreign import capi safe "HsBase.h write"
    c_safe_write :: CInt -> Ptr Word8 -> CSize -> IO CSsize
 
@@ -705,8 +690,44 @@ c_pipe _ = ioError (ioeSetLocation unsupportedOperation "pipe")
 foreign import ccall unsafe "HsBase.h pipe"
    c_pipe :: Ptr CInt -> IO CInt
 #endif
+
+foreign import capi unsafe "unistd.h lseek"
+   c_lseek :: CInt -> COff -> CInt -> IO COff
+
+foreign import ccall unsafe "HsBase.h access"
+   c_access :: CString -> CInt -> IO CInt
+
+#if !defined(HAVE_CHMOD)
+c_chmod :: CString -> CMode -> IO CInt
+c_chmod _ _ = ioError (ioeSetLocation unsupportedOperation "chmod")
+#else
+foreign import ccall unsafe "HsBase.h chmod"
+   c_chmod :: CString -> CMode -> IO CInt
+#endif
+
+foreign import ccall unsafe "HsBase.h close"
+   c_close :: CInt -> IO CInt
+
+foreign import ccall unsafe "HsBase.h creat"
+   c_creat :: CString -> CMode -> IO CInt
+
+#if !defined(HAVE_DUP)
+c_dup :: CInt -> IO CInt
+c_dup _ = ioError (ioeSetLocation unsupportedOperation "dup")
+
+c_dup2 :: CInt -> CInt -> IO CInt
+c_dup2 _ _ = ioError (ioeSetLocation unsupportedOperation "dup2")
+#else
+foreign import ccall unsafe "HsBase.h dup"
+   c_dup :: CInt -> IO CInt
+
+foreign import ccall unsafe "HsBase.h dup2"
+   c_dup2 :: CInt -> CInt -> IO CInt
 #endif
 
+foreign import ccall unsafe "HsBase.h isatty"
+   c_isatty :: CInt -> IO CInt
+
 foreign import ccall unsafe "HsBase.h unlink"
    c_unlink :: CString -> IO CInt
 
@@ -720,6 +741,7 @@ c_getpid = pure 1
 foreign import ccall unsafe "HsBase.h getpid"
    c_getpid :: IO CPid
 #endif
+#endif
 
 #if !defined(js_HOST_ARCH)
 foreign import ccall unsafe "HsBase.h __hscore_stat"
@@ -881,7 +903,8 @@ foreign import capi  unsafe "stdio.h value SEEK_END" sEEK_END :: CInt
 #endif
 
 {-
-Note: Windows types
+Note [Windows types]
+~~~~~~~~~~~~~~~~~~~~
 
 Windows' _read and _write have types that differ from POSIX. They take an
 unsigned int for length and return a signed int where POSIX uses size_t and

libraries/base/base.cabal

@@ -396,7 +396,6 @@ Library
     if os(windows)
         -- Windows requires some extra libraries for linking because the RTS
         -- is no longer re-exporting them.
-        -- mingwex: provides C99 compatibility. libm is a stub on MingW.
         -- mingw32: Unfortunately required because of a resource leak between
         --          mingwex and mingw32. the __math_err symbol is defined in
         --          mingw32 which is required by mingwex.
@@ -409,7 +408,7 @@ Library
         -- advapi32: provides advanced kernel functions
         extra-libraries:
             wsock32, user32, shell32, mingw32, kernel32, advapi32,
-            mingwex, ws2_32, shlwapi, ole32, rpcrt4, ntdll
+            ws2_32, shlwapi, ole32, rpcrt4, ntdll
         -- Minimum supported Windows version.
         -- These numbers can be found at:
         --  https://msdn.microsoft.com/en-us/library/windows/desktop/aa383745(v=vs.85).aspx

libraries/base/configure.ac

@@ -39,7 +39,7 @@ AC_CHECK_LIB([rt], [clock_gettime])
 AC_CHECK_FUNCS([clock_gettime])
 AC_CHECK_DECLS([CLOCK_PROCESS_CPUTIME_ID], [], [], [[#include <time.h>]])
 AC_CHECK_FUNCS([getclock getrusage times])
-AC_CHECK_FUNCS([_chsize ftruncate])
+AC_CHECK_FUNCS([_chsize_s ftruncate])
 
 # event-related fun
 # The line below already defines HAVE_KQUEUE and HAVE_POLL, so technically some of the

libraries/base/include/HsBase.h

@@ -280,15 +280,12 @@ __hscore_o_nonblock( void )
 INLINE int
 __hscore_ftruncate( int fd, off_t where )
 {
-#if defined(HAVE_FTRUNCATE)
+#if defined(HAVE__CHSIZE_S)
+  return _chsize_s(fd,where);
+#elif defined(HAVE_FTRUNCATE)
   return ftruncate(fd,where);
-#elif defined(HAVE__CHSIZE)
-  return _chsize(fd,where);
 #else
-// ToDo: we should use _chsize_s() on Windows which allows a 64-bit
-// offset, but it doesn't seem to be available from mingw at this time
-// --SDM (01/2008)
-#error at least ftruncate or _chsize functions are required to build
+#error at least _chsize_s or ftruncate functions are required to build
 #endif
 }
 

libraries/ghc-prim/ghc-prim.cabal

@@ -66,15 +66,14 @@ Library
     if os(windows)
         -- Windows requires some extra libraries for linking because the RTS
         -- is no longer re-exporting them (see #11223)
-        -- msvcrt: standard C library. The RTS will automatically include this,
-        --         but is added for completeness.
-        -- mingwex: provides C99 compatibility. libm is a stub on MingW.
+        -- ucrt: standard C library. The RTS will automatically include this,
+        --       but is added for completeness.
         -- mingw32: Unfortunately required because of a resource leak between
         --          mingwex and mingw32. the __math_err symbol is defined in
         --          mingw32 which is required by mingwex.
         -- user32: provides access to apis to modify user components (UI etc)
         --         on Windows. Required because of mingw32.
-        extra-libraries: user32, mingw32, mingwex, ucrt
+        extra-libraries: user32, mingw32, ucrt
 
     if os(linux)
         -- we need libm, but for musl and other's we might need libc, as libm

rts/Linker.c

@@ -135,7 +135,7 @@ extern void iconv();
    This is to enable lazy loading of symbols. Eager loading is problematic
    as it means that all symbols must be available, even those which we will
    never use. This is especially painful on Windows, where the number of
-   libraries required to link things like mingwex grows to be quite high.
+   libraries required to link things like QT or WxWidgets grows to be quite high.
 
    We proceed through these stages as follows,
 
@@ -193,7 +193,7 @@ extern void iconv();
 
    1) Dependency chains, if A.o required a .o in libB but A.o isn't required to link
       then we don't need to load libB. This means the dependency chain for libraries
-      such as mingw32 and mingwex can be broken down.
+      such as ucrt can be broken down.
 
    2) The number of duplicate symbols, since now only symbols that are
       true duplicates will display the error.
@@ -226,7 +226,7 @@ static void ghciRemoveSymbolTable(StrHashTable *table, const SymbolName* key,
 static const char *
 symbolTypeString (SymType type)
 {
-    switch (type) {
+    switch (type & ~SYM_TYPE_DUP_DISCARD) {
         case SYM_TYPE_CODE: return "code";
         case SYM_TYPE_DATA: return "data";
         case SYM_TYPE_INDIRECT_DATA: return "indirect-data";
@@ -275,14 +275,18 @@ int ghciInsertSymbolTable(
       insertStrHashTable(table, key, pinfo);
       return 1;
    }
-   else if (pinfo->type != type)
+   else if (pinfo->type ^ type)
    {
-       debugBelch("Symbol type mismatch.\n");
-       debugBelch("Symbol %s was defined by %" PATH_FMT " to be a %s symbol.\n",
-                  key, obj_name, symbolTypeString(type));
-       debugBelch("      yet was defined by %" PATH_FMT " to be a %s symbol.\n",
-                  pinfo->owner ? pinfo->owner->fileName : WSTR("<builtin>"),
-                  symbolTypeString(pinfo->type));
+       /* We were asked to discard the symbol on duplicates, do so quietly.  */
+       if (!(type & SYM_TYPE_DUP_DISCARD))
+       {
+         debugBelch("Symbol type mismatch.\n");
+         debugBelch("Symbol %s was defined by %" PATH_FMT " to be a %s symbol.\n",
+                    key, obj_name, symbolTypeString(type));
+         debugBelch("      yet was defined by %" PATH_FMT " to be a %s symbol.\n",
+                    pinfo->owner ? pinfo->owner->fileName : WSTR("<builtin>"),
+                    symbolTypeString(pinfo->type));
+       }
        return 1;
    }
    else if (pinfo->strength == STRENGTH_STRONG)

rts/LinkerInternals.h

@@ -54,11 +54,16 @@ typedef struct _Section    Section;
  */
 
 /* What kind of thing a symbol identifies. We need to know this to determine how
- * to process overflowing relocations. See Note [Processing overflowed relocations]. */
+ * to process overflowing relocations. See Note [Processing overflowed relocations].
+ * This is bitfield however only the option SYM_TYPE_DUP_DISCARD can be combined
+ * with the other values. */
 typedef enum _SymType {
-    SYM_TYPE_CODE, /* the symbol is a function and can be relocated via a jump island */
-    SYM_TYPE_DATA, /* the symbol is data */
-    SYM_TYPE_INDIRECT_DATA, /* see Note [_iob_func symbol] */
+    SYM_TYPE_CODE = 1 << 0, /* the symbol is a function and can be relocated via a jump island */
+    SYM_TYPE_DATA = 1 << 1, /* the symbol is data */
+    SYM_TYPE_INDIRECT_DATA = 1 << 2, /* see Note [_iob_func symbol] */
+    SYM_TYPE_DUP_DISCARD = 1 << 3, /* the symbol is a symbol in a BFD import library
+                                      however if a duplicate is found with a mismatching
+                                      SymType then discard this one.  */
 } SymType;
 
 

rts/RtsSymbols.c

@@ -113,26 +113,6 @@ extern char **environ;
  * by the RtsSymbols entry. To avoid this we introduce a horrible special case
  * in `ghciInsertSymbolTable`, ensure that `atexit` is never overridden.
  */
-/*
- * Note [Symbols for MinGW's printf]
- * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
- * The printf offered by Microsoft's libc implementation, msvcrt, is quite
- * incomplete, lacking support for even %ull. Consequently mingw-w64 offers its
- * own implementation which we enable. However, to be thread-safe the
- * implementation uses _lock_file. This would be fine except msvcrt.dll doesn't
- * export _lock_file, only numbered versions do (e.g. msvcrt90.dll).
- *
- * To work around this mingw-w64 packages a static archive of msvcrt which
- * includes their own implementation of _lock_file. However, this means that
- * the archive contains things which the dynamic library does not; consequently
- * we need to ensure that the runtime linker provides this symbol.
- *
- * It's all just so terrible.
- *
- * See also:
- * https://sourceforge.net/p/mingw-w64/wiki2/gnu%20printf/
- * https://sourceforge.net/p/mingw-w64/discussion/723797/thread/55520785/
- */
 /* Note [_iob_func symbol]
  * ~~~~~~~~~~~~~~~~~~~~~~~
  * Microsoft in VS2013 to VS2015 transition made a backwards incompatible change
@@ -170,12 +150,6 @@ extern char **environ;
       SymI_NeedsProto(__mingw_module_is_dll)             \
       RTS_WIN32_ONLY(SymI_NeedsProto(___chkstk_ms))      \
       RTS_WIN64_ONLY(SymI_NeedsProto(___chkstk_ms))      \
-      RTS_WIN64_ONLY(SymI_HasProto(__stdio_common_vswprintf_s)) \
-      RTS_WIN64_ONLY(SymI_HasProto(__stdio_common_vswprintf)) \
-      RTS_WIN64_ONLY(SymI_HasProto(_errno))  \
-      /* see Note [Symbols for MinGW's printf] */        \
-      SymI_HasProto(_lock_file)                          \
-      SymI_HasProto(_unlock_file)                        \
       SymI_HasProto(__mingw_vsnwprintf)                  \
       /* ^^ Need to figure out why this is needed.  */   \
       /* See Note [_iob_func symbol] */                  \
@@ -187,120 +161,8 @@ extern char **environ;
       /* ^^ Need to figure out why this is needed.  */   \
       SymI_HasProto(__mingw_vfprintf)                    \
       /* ^^ Need to figure out why this is needed.  */
-
-#define RTS_MINGW_COMPAT_SYMBOLS                         \
-      SymI_HasProto_deprecated(access)                   \
-      SymI_HasProto_deprecated(cabs)                     \
-      SymI_HasProto_deprecated(cgets)                    \
-      SymI_HasProto_deprecated(chdir)                    \
-      SymI_HasProto_deprecated(chmod)                    \
-      SymI_HasProto_deprecated(chsize)                   \
-      SymI_HasProto_deprecated(close)                    \
-      SymI_HasProto_deprecated(cprintf)                  \
-      SymI_HasProto_deprecated(cputs)                    \
-      SymI_HasProto_deprecated(creat)                    \
-      SymI_HasProto_deprecated(cscanf)                   \
-      SymI_HasProto_deprecated(cwait)                    \
-      SymI_HasProto_deprecated(dup)                      \
-      SymI_HasProto_deprecated(dup2)                     \
-      SymI_HasProto_deprecated(ecvt)                     \
-      SymI_HasProto_deprecated(eof)                      \
-      SymI_HasProto_deprecated(execl)                    \
-      SymI_HasProto_deprecated(execle)                   \
-      SymI_HasProto_deprecated(execlp)                   \
-      SymI_HasProto_deprecated(execlpe)                  \
-      SymI_HasProto_deprecated(execv)                    \
-      SymI_HasProto_deprecated(execve)                   \
-      SymI_HasProto_deprecated(execvp)                   \
-      SymI_HasProto_deprecated(execvpe)                  \
-      SymI_HasProto_deprecated(fcloseall)                \
-      SymI_HasProto_deprecated(fcvt)                     \
-      SymI_HasProto_deprecated(fdopen)                   \
-      SymI_HasProto_deprecated(fgetchar)                 \
-      SymI_HasProto_deprecated(filelength)               \
-      SymI_HasProto_deprecated(fileno)                   \
-      SymI_HasProto_deprecated(flushall)                 \
-      SymI_HasProto_deprecated(fputchar)                 \
-      SymI_HasProto_deprecated(gcvt)                     \
-      SymI_HasProto_deprecated(getch)                    \
-      SymI_HasProto_deprecated(getche)                   \
-      SymI_HasProto_deprecated(getcwd)                   \
-      SymI_HasProto_deprecated(getpid)                   \
-      SymI_HasProto_deprecated(getw)                     \
-      SymI_HasProto_deprecated(hypot)                    \
-      SymI_HasProto_deprecated(inp)                      \
-      SymI_HasProto_deprecated(inpw)                     \
-      SymI_HasProto_deprecated(isascii)                  \
-      SymI_HasProto_deprecated(isatty)                   \
-      SymI_HasProto_deprecated(iscsym)                   \
-      SymI_HasProto_deprecated(iscsymf)                  \
-      SymI_HasProto_deprecated(itoa)                     \
-      SymI_HasProto_deprecated(j0)                       \
-      SymI_HasProto_deprecated(j1)                       \
-      SymI_HasProto_deprecated(jn)                       \
-      SymI_HasProto_deprecated(kbhit)                    \
-      SymI_HasProto_deprecated(lfind)                    \
-      SymI_HasProto_deprecated(locking)                  \
-      SymI_HasProto_deprecated(lsearch)                  \
-      SymI_HasProto_deprecated(lseek)                    \
-      SymI_HasProto_deprecated(ltoa)                     \
-      SymI_HasProto_deprecated(memccpy)                  \
-      SymI_HasProto_deprecated(memicmp)                  \
-      SymI_HasProto_deprecated(mkdir)                    \
-      SymI_HasProto_deprecated(mktemp)                   \
-      SymI_HasProto_deprecated(open)                     \
-      SymI_HasProto_deprecated(outp)                     \
-      SymI_HasProto_deprecated(outpw)                    \
-      SymI_HasProto_deprecated(putch)                    \
-      SymI_HasProto_deprecated(putenv)                   \
-      SymI_HasProto_deprecated(putw)                     \
-      SymI_HasProto_deprecated(read)                     \
-      SymI_HasProto_deprecated(rmdir)                    \
-      SymI_HasProto_deprecated(rmtmp)                    \
-      SymI_HasProto_deprecated(setmode)                  \
-      SymI_HasProto_deprecated(sopen)                    \
-      SymI_HasProto_deprecated(spawnl)                   \
-      SymI_HasProto_deprecated(spawnle)                  \
-      SymI_HasProto_deprecated(spawnlp)                  \
-      SymI_HasProto_deprecated(spawnlpe)                 \
-      SymI_HasProto_deprecated(spawnv)                   \
-      SymI_HasProto_deprecated(spawnve)                  \
-      SymI_HasProto_deprecated(spawnvp)                  \
-      SymI_HasProto_deprecated(spawnvpe)                 \
-      SymI_HasProto_deprecated(strcmpi)                  \
-      SymI_HasProto_deprecated(strdup)                   \
-      SymI_HasProto_deprecated(stricmp)                  \
-      SymI_HasProto_deprecated(strlwr)                   \
-      SymI_HasProto_deprecated(strnicmp)                 \
-      SymI_HasProto_deprecated(strnset)                  \
-      SymI_HasProto_deprecated(strrev)                   \
-      SymI_HasProto_deprecated(strset)                   \
-      SymI_HasProto_deprecated(strupr)                   \
-      SymI_HasProto_deprecated(swab)                     \
-      SymI_HasProto_deprecated(tell)                     \
-      SymI_HasProto_deprecated(tempnam)                  \
-      SymI_HasProto_deprecated(toascii)                  \
-      SymI_HasProto_deprecated(tzset)                    \
-      SymI_HasProto_deprecated(ultoa)                    \
-      SymI_HasProto_deprecated(umask)                    \
-      SymI_HasProto_deprecated(ungetch)                  \
-      SymI_HasProto_deprecated(unlink)                   \
-      SymI_HasProto_deprecated(wcsdup)                   \
-      SymI_HasProto_deprecated(wcsicmp)                  \
-      SymI_HasProto_deprecated(wcsicoll)                 \
-      SymI_HasProto_deprecated(wcslwr)                   \
-      SymI_HasProto_deprecated(wcsnicmp)                 \
-      SymI_HasProto_deprecated(wcsnset)                  \
-      SymI_HasProto_deprecated(wcsrev)                   \
-      SymI_HasProto_deprecated(wcsset)                   \
-      SymI_HasProto_deprecated(wcsupr)                   \
-      SymI_HasProto_deprecated(write)                    \
-      SymI_HasProto_deprecated(y0)                       \
-      SymI_HasProto_deprecated(y1)                       \
-      SymI_HasProto_deprecated(yn)
 #else
 #define RTS_MINGW_ONLY_SYMBOLS /**/
-#define RTS_MINGW_COMPAT_SYMBOLS /**/
 #endif
 
 
@@ -1122,7 +984,6 @@ extern char **environ;
 #define SymI_HasProto(vvv) /**/
 #define SymI_HasDataProto(vvv) /**/
 #define SymI_HasProto_redirect(vvv,xxx,strength,ty) /**/
-#define SymI_HasProto_deprecated(vvv) /**/
 
 RTS_SYMBOLS
 RTS_RET_SYMBOLS
@@ -1140,7 +1001,6 @@ RTS_LIBFFI_SYMBOLS
 #undef SymI_HasProto
 #undef SymI_HasDataProto
 #undef SymI_HasProto_redirect
-#undef SymI_HasProto_deprecated
 #undef SymE_HasProto
 #undef SymE_HasDataProto
 #undef SymE_NeedsProto
@@ -1166,22 +1026,11 @@ RTS_LIBFFI_SYMBOLS
     { MAYBE_LEADING_UNDERSCORE_STR(#vvv),    \
       (void*)(&(xxx)), strength, ty },
 
-// SymI_HasProto_deprecated allows us to redirect references from their deprecated
-// names to the undeprecated ones. e.g. access -> _access.
-// We use the hexspeak for unallocated memory 0xBAADF00D to signal the RTS
-// that this needs to be loaded from somewhere else.
-// These are inserted as weak symbols to prevent us overriding packages that do
-// define them, since on Windows these functions shouldn't be in the top level
-// namespace, but we have them for POSIX compatibility.
-#define SymI_HasProto_deprecated(vvv)   \
-   { #vvv, (void*)0xBAADF00D, STRENGTH_WEAK, SYM_TYPE_CODE },
-
 RtsSymbolVal rtsSyms[] = {
       RTS_SYMBOLS
       RTS_RET_SYMBOLS
       RTS_POSIX_ONLY_SYMBOLS
       RTS_MINGW_ONLY_SYMBOLS
-      RTS_MINGW_COMPAT_SYMBOLS
       RTS_DARWIN_ONLY_SYMBOLS
       RTS_OPENBSD_ONLY_SYMBOLS
       RTS_LIBGCC_SYMBOLS

rts/linker/PEi386.c

@@ -261,6 +261,54 @@
             .asciiz "libfoo_data"
 
 
+   Note [GHC Linking model and import libraries]
+   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+   The above describes how import libraries work for static linking.
+   Fundamentally this does not apply to dynamic linking as we do in GHC.
+   The issue is two-folds:
+
+   1. In the linking model above it is expected that the .idata sections be
+      materialized into PLTs during linking.  However in GHC we never create
+      PLTs,  but have out own mechanism for this which is the jump island
+      machinery.   This is required for efficiency.  For one materializing the
+      .idata sections would result in wasting pages.   We'd use one page for
+      every ~100 bytes.  This is extremely wasteful and also fragments the
+      memory.  Secondly the dynamic linker is lazy.  We only perform the final
+      loading if the symbol is used, however with an import library we can
+      discard the actual OC immediately after reading it.   This prevents us from
+      keeping ~1k in memory per symbol for no reason.
+
+   2. GHC itself does not observe symbol visibility correctly during NGC.   This
+      in itself isn't an academic exercise.  The issue stems from GHC using one
+      mechanism for providing two incompatible linking modes:
+      a)  The first mode is generating Haskell shared libraries which are
+           intended to be used by other Haskell code.   This requires us to
+           export the info, data and closures.   For this GHC just re-exports
+           all symbols.  But it doesn't correcly mark data/code.  Symbol
+           visibility is overwritten by telling the linker to export all
+           symbols.
+      b)  The second code is producing code that's supposed to be call-able
+          through a C insterface.   This in reality does not require the
+          export of closures and info tables.  But also does not require the
+          inclusion of the RTS inside the DLL.  Hover this is done today
+          because we don't properly have the RTS as a dynamic library.
+          i.e.  GHC does not only export symbols denoted by foreign export.
+          Also GHC should depend on an RTS library, but at the moment it
+          cannot because of TNTC is incompatible with dynamic linking.
+
+   These two issues mean that for GHC we need to take a different approach
+   to handling import libraries.  For normal C libraries we have proper
+   differentiation between CODE and DATA.   For GHC produced import libraries
+   we do not.   As such the SYM_TYPE_DUP_DISCARD tells the linker that if a
+   duplicate symbol is found, and we were going to discard it anyway, just do
+   so quitely.  This works because the RTS symbols themselves are provided by
+   the currently loaded RTS as built-in symbols.
+
+   Secondly we cannot rely on a text symbol being available.   As such we
+   should only depend on the symbols as defined in the .idata sections,
+   otherwise we would not be able to correctly link against GHC produced
+   import libraries.
+
    Note [Memory allocation]
    ~~~~~~~~~~~~~~~~~~~~~~~~
    The loading of an object begins in `preloadObjectFile`, which allocates a buffer,
@@ -1658,7 +1706,10 @@ ocGetNames_PEi386 ( ObjectCode* oc )
       if (   secNumber != IMAGE_SYM_UNDEFINED
           && secNumber > 0
           && section
-          && section->kind != SECTIONKIND_BFD_IMPORT_LIBRARY) {
+          /* Skip all BFD import sections.  */
+          && section->kind != SECTIONKIND_IMPORT
+          && section->kind != SECTIONKIND_BFD_IMPORT_LIBRARY
+          && section->kind != SECTIONKIND_BFD_IMPORT_LIBRARY_HEAD) {
          /* This symbol is global and defined, viz, exported */
          /* for IMAGE_SYMCLASS_EXTERNAL
                 && !IMAGE_SYM_UNDEFINED,
@@ -1691,12 +1742,49 @@ ocGetNames_PEi386 ( ObjectCode* oc )
           IF_DEBUG(linker_verbose, debugBelch("bss symbol @ %p %u\n", addr, symValue));
       }
       else if (section && section->kind == SECTIONKIND_BFD_IMPORT_LIBRARY) {
-          setImportSymbol(oc, sname);
+          /* Disassembly of section .idata$5:
+
+             0000000000000000 <__imp_Insert>:
+             ...
+                        0: IMAGE_REL_AMD64_ADDR32NB     .idata$6
+
+             The first two bytes contain the ordinal of the function
+             in the format of lowpart highpart. The two bytes combined
+             for the total range of 16 bits which is the function export limit
+             of DLLs.  See note [GHC Linking model and import libraries].  */
+          sname = (SymbolName*)section->start+2;
+          COFF_symbol* sym = &oc->info->symbols[info->numberOfSymbols-1];
+          addr = get_sym_name( getSymShortName (info, sym), oc);
+
+          IF_DEBUG(linker,
+                   debugBelch("addImportSymbol `%s' => `%s'\n",
+                              sname, (char*)addr));
+          /* We're going to free the any data associated with the import
+             library without copying the sections.  So we have to duplicate
+             the symbol name and values before the pointers become invalid.  */
+          sname = strdup (sname);
+          addr  = strdup (addr);
+          type = has_code_section ? SYM_TYPE_CODE : SYM_TYPE_DATA;
+          type |= SYM_TYPE_DUP_DISCARD;
+          if (!ghciInsertSymbolTable(oc->fileName, symhash, sname,
+                                     addr, false, type, oc)) {
+             releaseOcInfo (oc);
+             stgFree (oc->image);
+             oc->image = NULL;
+             return false;
+          }
+          setImportSymbol (oc, sname);
+
+          /* Don't process this oc any further. Just exit.  */
+          oc->n_symbols = 0;
+          oc->symbols   = NULL;
+          stgFree (oc->image);
+          oc->image = NULL;
+          releaseOcInfo (oc);
           // There is nothing that we need to resolve in this object since we
           // will never call the import stubs in its text section
           oc->status = OBJECT_DONT_RESOLVE;
-
-          IF_DEBUG(linker_verbose, debugBelch("import symbol %s\n", sname));
+          return true;
       }
       else if (secNumber > 0
                && section
@@ -2171,21 +2259,7 @@ SymbolAddr *lookupSymbol_PEi386(SymbolName *lbl, ObjectCode *dependent, SymType
     } else {
         if (type) *type = pinfo->type;
 
-        // If Windows, perform initialization of uninitialized
-        // Symbols from the C runtime which was loaded above.
-        // We do this on lookup to prevent the hit when
-        // The symbol isn't being used.
-        if (pinfo->value == (void*)0xBAADF00D)
-        {
-            char symBuffer[50];
-            const char *crt_impl = "ucrtbase";
-            sprintf(symBuffer, "_%s", lbl);
-            static HMODULE crt = NULL;
-            if (!crt) crt = GetModuleHandle(crt_impl);
-            pinfo->value = GetProcAddress(crt, symBuffer);
-            return pinfo->value;
-        }
-        else if (pinfo && pinfo->owner && isSymbolImport (pinfo->owner, lbl))
+        if (pinfo && pinfo->owner && isSymbolImport (pinfo->owner, lbl))
         {
             /* See Note [BFD import library].  */
             HINSTANCE dllInstance = (HINSTANCE)lookupDependentSymbol(pinfo->value, dependent, type);

rts/rts.cabal.in

@@ -24,8 +24,6 @@ flag need-pthread
   default: @CabalNeedLibpthread@
 flag libbfd
   default: @CabalHaveLibbfd@
-flag mingwex
-  default: @CabalMingwex@
 flag need-atomic
   default: @CabalNeedLibatomic@
 flag libdw
@@ -68,7 +66,6 @@ library
 
     exposed: True
     exposed-modules:
-
     if os(ghcjs)
 
       include-dirs: include
@@ -194,8 +191,6 @@ library
       if flag(libbfd)
          -- for debugging
          extra-libraries: bfd iberty
-      if flag(mingwex)
-         extra-libraries: mingwex
       if flag(libdw)
          -- for backtraces
          extra-libraries: elf dw

testsuite/tests/ghci/linking/dyn/Makefile

@@ -88,10 +88,6 @@ compile_libAB_dyn:
 
 .PHONY: compile_libAS_impl_gcc
 compile_libAS_impl_gcc:
-	rm -rf bin_impl_gcc
-	mkdir bin_impl_gcc
-	'$(TEST_HC)' $(MY_TEST_HC_OPTS) -odir "bin_impl_gcc" -shared A.c -o "bin_impl_gcc/$(call DLL,ASimpL)"
-	mv bin_impl_gcc/libASimpL.dll.a bin_impl_gcc/libASx.dll.a
 	echo "main" | '$(TEST_HC)' $(TEST_HC_OPTS_INTERACTIVE) T11072.hs -lASx -L./bin_impl_gcc
 
 .PHONY: compile_libAS_impl_msvc

testsuite/tests/ghci/linking/dyn/all.T

@@ -41,9 +41,9 @@ test('T10458',
       extra_hc_opts('-L"$PWD/T10458dir" -lAS')],
      ghci_script, ['T10458.script'])
 
-test('T11072gcc', [extra_files(['A.c', 'T11072.hs']),
-                   expect_broken(18718),
-                   unless(doing_ghci, skip), unless(opsys('mingw32'), skip)],
+test('T11072gcc', [extra_files(['A.c', 'T11072.hs', 'bin_impl_gcc/']),
+                   unless(doing_ghci, skip), unless(opsys('mingw32'), skip),
+                   unless(arch('x86_64'), skip)],
      makefile_test, ['compile_libAS_impl_gcc'])
 
 test('T11072msvc', [extra_files(['A.c', 'T11072.hs', 'libAS.def', 'i686/', 'x86_64/']),

testsuite/tests/rts/all.T

@@ -410,7 +410,7 @@ test('T10296b', [only_ways(['threaded2'])], compile_and_run, [''])
 test('numa001', [ extra_run_opts('8'), unless(unregisterised(), extra_ways(['debug_numa'])) ]
                 , compile_and_run, [''])
 
-test('T12497', [ unless(opsys('mingw32'), skip)
+test('T12497', [ unless(opsys('mingw32'), skip), expect_broken(22694)
                ],
                makefile_test, ['T12497'])