Order of libraries and source files in the f18 frontend

[coti]

Summary

When the f18 frontend calls the link editor, put the libraries and object files in the correct order.

Fixes the issues reported here https://github.com/flang-compiler/flang/issues/897

[DavidTruby]

flang/tools/f18/f18.cpp

432

Should the prefix be from 0 to dot, instead of from 0 to 2?

[coti]

Replied comment from @DavidTruby.

flang/tools/f18/f18.cpp

432

The prefix variable is simply here to determine if we are linking against a dynamic library (it is used line 454 and only there), ie, if the string is starting by -l. This might not be the most appropriate variable name though.

[AlexisPerry]

This looks good to me. I think these changes mean that the vector relocatables never actually gets populated, so it could be removed since the patch uses objlist and liblist exclusively, which are clearer names anyway.

[coti]

@AlexisPerry is right, I removed the vector relocatable.

[coti]

clang-formated the source code, since I have been told about issues with whitespaces.

If this is fine, can anyone with commit access push it? Thanks!

flang/tools/f18/f18.cpp

if (!driver.compileOnly && driver.outputPath.empty()) {
       filesToDelete.push_back(relo);
     }
     return relo;
   }
   RunOtherCompiler(driver, path.data(), relo.data());
   return {};
 }
 
-void Link(std::vector<std::string> &relocatables, DriverOptions &driver) {
+void Link(std::vector<std::string> &liblist, std::vector<std::string> &objects,
+    DriverOptions &driver) {
   if (!ParentProcess()) {
     std::vector<char *> argv;
     for (size_t j{0}; j < driver.F18_FCArgs.size(); ++j) {
       argv.push_back(driver.F18_FCArgs[j].data());
     }
-    for (auto &relo : relocatables) {
-      argv.push_back(relo.data());
+    for (auto &obj : objects) {
+      argv.push_back(obj.data());
     }
     if (!driver.outputPath.empty()) {
       char dashO[3] = "-o";
       argv.push_back(dashO);
       argv.push_back(driver.outputPath.data());
     }
+    for (auto &lib : liblist) {
+      argv.push_back(lib.data());
+    }
     Exec(argv, driver.verbose);
   }
 }
 
 int main(int argc, char *const argv[]) {
 
   atexit(CleanUpAtExit);
 
   DriverOptions driver;
   const char *F18_FC{getenv("F18_FC")};
   driver.F18_FCArgs.push_back(F18_FC ? F18_FC : "gfortran");
   bool isPGF90{driver.F18_FCArgs.back().rfind("pgf90") != std::string::npos};
 
   std::list<std::string> args{argList(argc, argv)};
+  std::vector<std::string> objlist, liblist;
   std::string prefix{args.front()};
   args.pop_front();
   prefix += ": ";
   driver.prefix = prefix.data();
 
   Fortran::parser::Options options;
   options.predefinitions.emplace_back("__F18", "1");
   options.predefinitions.emplace_back("__F18_MAJOR__", "1");
   options.predefinitions.emplace_back("__F18_MINOR__", "1");
   options.predefinitions.emplace_back("__F18_PATCHLEVEL__", "1");
 #if __x86_64__
   options.predefinitions.emplace_back("__x86_64__", "1");
 #endif
 
   Fortran::common::IntrinsicTypeDefaultKinds defaultKinds;
 
-  std::vector<std::string> fortranSources, otherSources, relocatables;
+  std::vector<std::string> fortranSources, otherSources;
   bool anyFiles{false};
 
   while (!args.empty()) {
     std::string arg{std::move(args.front())};
+    auto dot{arg.rfind(".")};
+    std::string suffix{arg.substr(dot + 1)};
+    std::string prefix{arg.substr(0, 2)};
     args.pop_front();
     if (arg.empty()) {
     } else if (arg.at(0) != '-') {
       anyFiles = true;
-      auto dot{arg.rfind(".")};
       if (dot == std::string::npos) {
         driver.F18_FCArgs.push_back(arg);
       } else {
-        std::string suffix{arg.substr(dot + 1)};
         if (suffix == "f" || suffix == "F" || suffix == "ff" ||
             suffix == "f90" || suffix == "F90" || suffix == "ff90" ||
             suffix == "f95" || suffix == "F95" || suffix == "ff95" ||
             suffix == "cuf" || suffix == "CUF" || suffix == "f18" ||
             suffix == "F18" || suffix == "ff18") {
           fortranSources.push_back(arg);
-        } else if (suffix == "o" || suffix == "a") {
-          relocatables.push_back(arg);
+        } else if (suffix == "o" || suffix == "so") {
+          objlist.push_back(arg);
+        } else if (suffix == "a") {
+          liblist.push_back(arg);
         } else {
           otherSources.push_back(arg);
         }
       }
+    } else if (prefix == "-l" || suffix == "a") {
+      liblist.push_back(arg);
     } else if (arg == "-") {
       fortranSources.push_back("-");
     } else if (arg == "--") {
       while (!args.empty()) {
         fortranSources.emplace_back(std::move(args.front()));
         args.pop_front();
       }
       break;
if (!anyFiles) {
     driver.measureTree = true;
     driver.dumpUnparse = true;
     CompileFortran("-", options, driver, defaultKinds);
     return exitStatus;
   }
   for (const auto &path : fortranSources) {
     std::string relo{CompileFortran(path, options, driver, defaultKinds)};
     if (!driver.compileOnly && !relo.empty()) {
-      relocatables.push_back(relo);
+      objlist.push_back(relo);
     }
   }
   for (const auto &path : otherSources) {
     std::string relo{CompileOtherLanguage(path, driver)};
     if (!driver.compileOnly && !relo.empty()) {
-      relocatables.push_back(relo);
+      objlist.push_back(relo);
     }
   }
-  if (!relocatables.empty()) {
-    Link(relocatables, driver);
+  if (!objlist.empty()) {
+    Link(liblist, objlist, driver);
   }
   return exitStatus;
 }