From e893335ed8fab65f7de5584aacd9318efe251cdd Mon Sep 17 00:00:00 2001 From: Martin Storsjo Date: Mon, 23 Oct 2017 09:08:13 +0000 Subject: [PATCH] [COFF] Improve the check for functions that should get an extra underscore This fixes exporting functions starting with an underscore, and fully decorated fastcall/vectorcall functions. Tests will be added in the lld repo. Differential Revision: https://reviews.llvm.org/D39168 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@316316 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Object/COFFModuleDefinition.cpp | 24 ++++++++++++++++--- .../llvm-dlltool/DlltoolDriver.cpp | 5 ++-- 2 files changed, 24 insertions(+), 5 deletions(-) diff --git a/lib/Object/COFFModuleDefinition.cpp b/lib/Object/COFFModuleDefinition.cpp index 510eac8b239..6ea6015eabc 100644 --- a/lib/Object/COFFModuleDefinition.cpp +++ b/lib/Object/COFFModuleDefinition.cpp @@ -57,9 +57,27 @@ struct Token { }; static bool isDecorated(StringRef Sym, bool MingwDef) { - // mingw does not prepend "_". - return (!MingwDef && Sym.startswith("_")) || Sym.startswith("@") || - Sym.startswith("?"); + // In def files, the symbols can either be listed decorated or undecorated. + // + // - For cdecl symbols, only the undecorated form is allowed. + // - For fastcall and vectorcall symbols, both fully decorated or + // undecorated forms can be present. + // - For stdcall symbols in non-MinGW environments, the decorated form is + // fully decorated with leading underscore and trailing stack argument + // size - like "_Func@0". + // - In MinGW def files, a decorated stdcall symbol does not include the + // leading underscore though, like "Func@0". + + // This function controls whether a leading underscore should be added to + // the given symbol name or not. For MinGW, treat a stdcall symbol name such + // as "Func@0" as undecorated, i.e. a leading underscore must be added. + // For non-MinGW, look for '@' in the whole string and consider "_Func@0" + // as decorated, i.e. don't add any more leading underscores. + // We can't check for a leading underscore here, since function names + // themselves can start with an underscore, while a second one still needs + // to be added. + return Sym.startswith("@") || Sym.contains("@@") || Sym.startswith("?") || + (!MingwDef && Sym.contains('@')); } static Error createError(const Twine &Err) { diff --git a/lib/ToolDrivers/llvm-dlltool/DlltoolDriver.cpp b/lib/ToolDrivers/llvm-dlltool/DlltoolDriver.cpp index eb9b9c3b264..3891efae57b 100644 --- a/lib/ToolDrivers/llvm-dlltool/DlltoolDriver.cpp +++ b/lib/ToolDrivers/llvm-dlltool/DlltoolDriver.cpp @@ -165,8 +165,9 @@ int llvm::dlltoolDriverMain(llvm::ArrayRef ArgsArr) { E.SymbolName = E.Name; // Trim off the trailing decoration. Symbols will always have a // starting prefix here (either _ for cdecl/stdcall, @ for fastcall - // or ? for C++ functions). (Vectorcall functions also will end up having - // a prefix here, even if they shouldn't.) + // or ? for C++ functions). Vectorcall functions won't have any + // fixed prefix, but the function base name will still be at least + // one char. E.Name = E.Name.substr(0, E.Name.find('@', 1)); // By making sure E.SymbolName != E.Name for decorated symbols, // writeImportLibrary writes these symbols with the type -- 2.40.0