MSVC 2012+: Permit linking to 32-bit, MinGW-built libraries.

nmisch · nmisch · commit 70dc7ad584f5 · 2017-12-09T00:58:59.000-08:00
Notably, this permits linking to the 32-bit Perl binaries advertised on perl.org, namely Strawberry Perl and ActivePerl. This has a side effect of permitting linking to binaries built with obsolete MSVC versions. By default, MSVC 2012 and later require a "safe exception handler table" in each binary. MinGW-built, 32-bit DLLs lack the relevant exception handler metadata, so linking to them failed with error LNK2026. Restore the semantics of MSVC 2010, which omits the table from a given binary if some linker input lacks metadata. This has no effect on 64-bit builds or on MSVC 2010 and earlier. Back-patch to 9.3 (all supported versions). Reported by Victor Wagner. Discussion: https://postgr.es/m/20160326154321.7754ab8f@wagner.wagner.home
diff --git a/src/tools/msvc/MSBuildProject.pm b/src/tools/msvc/MSBuildProject.pm
@@ -320,6 +320,8 @@ sub WriteItemDefinitionGroup
       <GenerateMapFile>false</GenerateMapFile>
       <MapFileName>.\\$cfgname\\$self->{name}\\$self->{name}.map</MapFileName>
       <RandomizedBaseAddress>false</RandomizedBaseAddress>
+      <!-- Permit links to MinGW-built, 32-bit DLLs (default before VS2012). -->
+      <ImageHasSafeExceptionHandlers/>
       <SubSystem>Console</SubSystem>
       <TargetMachine>$targetmachine</TargetMachine>
 EOF
