| Title | The MPS is not a Windows DLL |
| Status | closed |
| Priority | essential |
| Assigned user | David Jones |
| Organization | Ravenbrook |
| Description | Configura would like a DLL. See [1] See < http://info.ravenbrook.com/mail/2005/10/12/15-40-18/0.txt> [6] for requirements See mps/branch/2004-12-15/dll for implementation. |
| Analysis | See [2] State of Play 2005-01-28 DRJ Proceeding as outlined in [5]. 2004-12-16 DRJ Added mps.dll target to commpost.nmk. Realised that this may be wrong name as that means that the import library for the mps.dll dll will be mps.lib which conflicts with (is the same as) the name of the static mps library. This is why we see things like SPONGDLL.DLL. [2005-02-08 DRJ: This is now mpsdy.dll] mps.dll does not build properly. Specifically: D:\home\drj\info.ravenbrook.com\project\mps\branch\2004-12-15\dll\code>nmake /f w3i3mv.nmk VARIETY=we mps.dll Microsoft (R) Program Maintenance Utility Version 6.00.8168.0 Copyright (C) Microsoft Corp 1988-1998. All rights reserved. w3i3mv\we\version.obj version.c w3i3mv\we\mps.dll mpm.obj : error LNK2001: unresolved external symbol _mps_lib_get_EOF mpm.obj : error LNK2001: unresolved external symbol _mps_lib_fputs mpm.obj : error LNK2001: unresolved external symbol _mps_lib_fputc global.obj : error LNK2001: unresolved external symbol _mps_clock global.obj : error LNK2001: unresolved external symbol _mps_clocks_per_sec dbgpool.obj : error LNK2001: unresolved external symbol _mps_lib_assert_fail w3i3mv\we\mps.dll : fatal error LNK1120: 6 unresolved externals NMAKE : fatal error U1077: 'link' : return code '0x460' Stop. NMAKE : fatal error U1077: 'C:\PROGRA~1\MICROS~3\VC98\BIN\NMAKE.EXE' : return code '0x2' Stop. Looks like we need to tell the linker that these symbols will be provided by someone else. You see phrases like this in the MSDN doc: "However, when a DLL exports to a program that it also imports from, whether directly or indirectly, you must use LIB to create one of the import libraries. When LIB creates an import library, it also creates an export file. You must use the export file when linking one of the DLLs." We are in that situation. mps.dll exports symbols (to the client program) and also imports symbols, namely the plinth functions. So I need an export file. So I need to use LIB. 2004-12-15 DRJ According to [2] we need to use /LD when compiling .c to .obj and /link /dll when linking. It looks like we will need to ship a .DLL and a .LIB (the import library against which client programs will link). Zlib have a good DLL war story, See [4]. Configura use (when compiling and linking the DLL objects): /W3 /WX /Gf /Gy /Gs /G6 /Zi /ML /LD Which, according to http://msdn.microsoft.com/library/defa...ccore/html/_core_Compiler_Reference.asp,is decoded as follows: W3 warning level 3 WX warnings as errors Gf pool strings (read-write), note, GF is read-only pooled. Cool. Gy function level linking Gs stack probe control (use without a decimal number undocumented) G6 optimised for Pentium Pro, II, III, P4. Zi produce a PDB for debug info ML instruct linker to link to LIBC.lib LD create a DLL /LD and /ML being the crucial options. On Exporting Symbols When the DLL is built the exported symbols need to be identified. There are 3 ways to do this (from MSDN): 1) The __declspec(dllexport) keyword in the source code 2) An EXPORTS statement in a .def file 3) An /EXPORT specification in a LINK command Method 1) involves modifying the source code which is distasteful. 2) seems like the way to go. We need to create a .DEF file which has an EXPORTS statement. Like this: .def file: EXPORTS mps_rank_ambig mps_arena_clamp ... The .def files is specifies to the linker using the /DEF option. and so on. Generating this list seems a bit tedious. /Zg might be useful or not, it seems it only generates prototypes for defined functions). Maybe we can generate the list on a suitable GNU enabled unix platform. After all the list of exported symbols (from mps.h) isn't going to change (much?) between different platforms. Investigating gcc -fdump-translation-unit -fdump-tree ouptut of -fdump-translation-unit looks parsable. #!/bin/sh awk ' $2=="function_decl" && $7=="srcp:" && $8 ~ /^mps\.h:/ {print $4 >"fun"} $2=="identifier_node"{print $1,$4 >"name"} ' mps.h.tu join fun name >join Warning: gcc mps.h produces an _evil_ mps.h.gch file which will silently corrupt future compilations. Work out how to suppress that. Need to do this for other header files too (pool class header files). See expgen.sh On Object Files If we really do need different options when compiling .c to .obj (/LD) then we need a different platform (or possibly variety). It's like another axis in the platform space, perhaps a bit like the different ABI options that some UNIX platforms (EG IRIX 6) have. I have a vague memory that we used to give object files to DylanWorks so that they could build their own DLL, I don't think that we treated the object files in any special way (and there's no evidence that I've found in the build system that we treated them either). RHSK 2005-10-12 Design (from [6]): .des.functions: Code can call MPS functions directly. (.req.simple). .des.functions.linker: All we need to do is export MPS functions from a DLL, and the OS will link all calling code for us. .des.functions.mps-dll: We choose to make a separate MPS DLL, which exports all MPS functions. .des.functions.mps-dll.plinth: In order to keep this separate MPS DLL client-agnostic, it requires the client to manually register all mpslib.h callbacks. See <manual/supplement/dll-notes/>. .note.mps-only.nonreq: Now that the MPS is a separate DLL, it could support Configura code that wants the MPS but not anything else from CMSupport.dll. But this is not a requirement (we just happened to get it 'for free'). .des.macros: Code needs to be able to use MPS facilities that are currently implemented as C macros, such as mps_reserve(). (.req.efficient). .des.macros.include: Code that calls MPS should #include mps.h. (Where client code is shielded from knowledge of MPS details by, for example, a collection class, the class should of course perform this #include too). |
| How found | customer |
| Evidence | [1] Configura say they would like a DLL://info.ravenbrook.com/mail/2004/12/07/12-17-35/0.txt[2] More useful discussion and some command line options: //info.ravenbrook.com/mail/2004/12/08/12-20-42/0.txt[3] MSDN Linker doc, EXPORT statements in .def files. Note that this link will probably not work by the time you use it because MSDN gets reorganised a lot. http://msdn.microsoft.com/library/defa...ary/en-us/vccore/html/_core_exports.asp[4] Zlib DLL war story. http://www.zlib.net/DLL_FAQ.txt[5] drj's suggested design of a callback interface: //info.ravenbrook.com/mail/2005/01/27/11-17-48/0.txt[6] rhsk's wrap-up of requirements and design: < http://info.ravenbrook.com/mail/2005/10/12/15-40-18/0.txt> |
| Observed in | 1.104.0 |
| Created by | David Jones |
| Created on | 2004-12-15 11:52:01 |
| Last modified by | Gareth Rees |
| Last modified on | 2013-03-19 11:22:18 |
| History | 2004-12-15 DRJ Created. 2005-02-08 DRJ Updated. 2005-10-12 RHSK Closed. Noted design here. Mailed wrap-up [6] to Configura. |
| Change | Effect | Date | User | Description |
|---|---|---|---|---|
| 179602 | closed | 2012-09-21 09:46:50 | Richard Brooksby | Adding baseline Visual Studio project for building the MPS. Only the amcss test is included for W3I3MV so far. |
| 155369 | closed | 2005-10-12 11:20:38 | Richard Kistruck | MPS: comments only: add licence text; add: works with gcc 3.3, not 4.0 |
| 155267 | open | 2005-10-06 12:23:07 | Richard Kistruck | build-notes: make text+k; add Windows section; now /Gs /GZ (for DLL) |
| 155265 | open | 2005-10-06 12:15:10 | Richard Kistruck | dll-notes: make it a proper doc: add intro etc; corrections and clarity. |
| 155264 | open | 2005-10-06 11:42:11 | Richard Kistruck | MPS DLL notes |
| 155259 | open | 2005-10-05 18:37:41 | Richard Kistruck | add copyright and licence notices |
| 144811 | open | 2005-02-16 11:36:22 | David Jones | MPS: Windows linker problem. |
| 144809 | open | 2005-02-16 11:20:41 | David Jones | MPS: Bug in linker line |
| 144807 | open | 2005-02-16 11:10:42 | David Jones | MPS: removing windows compiler warning |
| 144799 | open | 2005-02-16 10:19:55 | David Jones | MPS: removing mpm.h from mpslibcb.c |
| 143481 | open | 2005-02-08 12:45:47 | David Jones | MPS: mpsplcb.lib target |
| 143475 | open | 2005-02-08 12:34:31 | David Jones | MPS: Updated generated file w3gen.def |
| 143474 | open | 2005-02-08 12:32:49 | David Jones | MPS: Documented procedure for rebuilding w3gen.def |
| 143471 | open | 2005-02-08 12:22:54 | David Jones | MPS: new files in windows makefiles |
| 143314 | open | 2005-02-07 14:50:11 | David Jones | MPS: mpslib via client callbacks. mpslib.c |
| 134030 | open | 2004-12-16 17:01:58 | David Jones | mps: more dll tweaking. Still broken. |
| 134028 | open | 2004-12-16 16:58:49 | David Jones | MPS: Adjusting list of exported functions. |
| 134017 | open | 2004-12-16 16:03:00 | David Jones | MPS: Adding mps.dll target. Does not work (yet). |
| 133985 | open | 2004-12-16 12:17:13 | David Jones | MPS: expgen script to generate a list of exported symbols. And its output. |