Tamar Christina pushed to branch wip/bump-win32-tarballs at Glasgow Haskell Compiler / GHC Commits: e3bfc624 by Tamar Christina at 2025-07-06T12:25:24+01:00 rts: Implement WEAK EXTERNAL undef redirection by target symbol name - - - - - 1 changed file: - rts/linker/PEi386.c Changes: ===================================== rts/linker/PEi386.c ===================================== @@ -1168,7 +1168,11 @@ bool checkAndLoadImportLibrary( pathchar* arch_name, char* member_name, FILE* f // way is to load the symbol immediately. We already have all the // information so might as well SymbolAddr* sym = lookupSymbolInDLL_PEi386 (symbol, instance, dll, NULL); - ASSERT(sym); + + // Could be an import descriptor etc, skip if no symbol. + if (!sym) + return true; + // The symbol must have been found, and we can add it to the RTS symbol table IF_DEBUG(linker, debugBelch("checkAndLoadImportLibrary: resolved symbol %s to %p\n", symbol, sym)); // Because the symbol has been loaded before we actually need it, if a @@ -1932,6 +1936,27 @@ ocGetNames_PEi386 ( ObjectCode* oc ) } if(NULL != targetSection) addr = (SymbolAddr*) ((size_t) targetSection->start + getSymValue(info, targetSym)); + else + { + // Do the symbol lookup based on name, this follows Microsoft's weak external's + // format 3 specifications. Example header generated: + // api-ms-win-crt-stdio-l1-1-0.dll: file format pe-x86-64 + // + // SYMBOL TABLE: + // [ 0](sec -1)(fl 0x00)(ty 0)(scl 3) (nx 0) 0x0000000000000000 @comp.id + // [ 1](sec -1)(fl 0x00)(ty 0)(scl 3) (nx 0) 0x0000000000000000 @feat.00 + // [ 2](sec 0)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000000 _write + // [ 3](sec 0)(fl 0x00)(ty 0)(scl 105) (nx 1) 0x0000000000000000 write + // AUX lnno 3 size 0x0 tagndx 2 + // + // https://learn.microsoft.com/en-us/windows/win32/debug/pe-format#auxiliary-fo... + SymbolName *target_sname = get_sym_name (getSymShortName (info, targetSym), oc); + if (target_sname) + addr = lookupSymbol_PEi386 (target_sname, oc, &type); + + IF_DEBUG(linker, debugBelch("weak external symbol @ %s => %s resolved to %p\n", \ + sname, target_sname, addr)); + } } else if ( secNumber == IMAGE_SYM_UNDEFINED && symValue > 0) { /* This symbol isn't in any section at all, ie, global bss. View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/e3bfc62416dd738bfd1a4464f0a622c9... -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/e3bfc62416dd738bfd1a4464f0a622c9... You're receiving this email because of your account on gitlab.haskell.org.