For PR521:

With these patches we implement the ability for the Linker library to
keep track of which libraries were actually bytecode files (not archives)
and cause their users to remove such files from the list of libraries to
pass to the native linker.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@25169 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Linker.h

@@ -158,7 +158,8 @@ class Linker {
     /// @see getLastError
     /// @throws nothing
     bool LinkInItems (
-      const ItemList& Items // Set of libraries/files to link in
+      const ItemList& Items, ///< Set of libraries/files to link in
+      ItemList& NativeItems  ///< Output list of native files/libs
     );
 
     /// This function links the bytecode \p Files into the composite module.
@@ -210,7 +211,8 @@ class Linker {
     /// @returns true if an error occurs, false otherwise
     /// @brief Link one library into the module
     bool LinkInLibrary (
-      const std::string& Library ///< The library to link in
+      const std::string& Library, ///< The library to link in
+      bool& is_file               ///< Indicates if lib is really a bc file
     );
 
     /// This function links one bytecode archive, \p Filename, into the module.

lib/Linker/LinkItems.cpp

@@ -17,17 +17,28 @@
 
 using namespace llvm;
 
-// LinkItems - preserve link order for an arbitrary set of linkage items.
+// LinkItems - This function is the main entry point into linking. It takes a
+// list of LinkItem which indicates the order the files should be linked and
+// how each file should be treated (plain file or with library search). The
+// function only links bytecode and produces a result list of items that are
+// native objects. 
 bool
-Linker::LinkInItems(const ItemList& Items) {
+Linker::LinkInItems(const ItemList& Items, ItemList& NativeItems) {
+  // Clear the NativeItems just in case
+  NativeItems.clear();
+
   // For each linkage item ...
   for (ItemList::const_iterator I = Items.begin(), E = Items.end();
        I != E; ++I) {
     if (I->second) {
       // Link in the library suggested.
-      if (LinkInLibrary(I->first))
+      bool is_file = true;
+      if (LinkInLibrary(I->first,is_file))
         return true;
+      if (!is_file)
+        NativeItems.push_back(*I);
     } else {
+      // Link in the file suggested
       if (LinkInFile(sys::Path(I->first)))
         return true;
     }
@@ -38,9 +49,10 @@ Linker::LinkInItems(const ItemList& Items) {
   // that module should also be aggregated with duplicates eliminated. This is
   // now the time to process the dependent libraries to resolve any remaining
   // symbols.
+  bool is_bytecode;
   for (Module::lib_iterator I = Composite->lib_begin(),
          E = Composite->lib_end(); I != E; ++I)
-    if(LinkInLibrary(*I))
+    if(LinkInLibrary(*I, is_bytecode))
       return true;
 
   return false;
@@ -49,25 +61,30 @@ Linker::LinkInItems(const ItemList& Items) {
 
 /// LinkInLibrary - links one library into the HeadModule.
 ///
-bool Linker::LinkInLibrary(const std::string& Lib) {
+bool Linker::LinkInLibrary(const std::string& Lib, bool& is_file) {
+  is_file = false;
   // Determine where this library lives.
   sys::Path Pathname = FindLib(Lib);
   if (Pathname.isEmpty())
     return warning("Cannot find library '" + Lib + "'");
 
   // If its an archive, try to link it in
-  if (Pathname.isArchive()) {
-    if (LinkInArchive(Pathname))
-      return error("Cannot link archive '" + Pathname.toString() + "'");
-  } else if (Pathname.isBytecodeFile()) {
-    // LLVM ".so" file.
-    if (LinkInFile(Pathname))
-      return error("Cannot link file '" + Pathname.toString() + "'");
-
-  } else if (Pathname.isDynamicLibrary()) {
-    return warning("Library '" + Lib + "' is a native dynamic library.");
-  } else {
-    return warning("Supposed library '" + Lib + "' isn't a library.");
+  std::string Magic;
+  Pathname.getMagicNumber(Magic, 64);
+  switch (sys::IdentifyFileType(Magic.c_str(), 64)) {
+    case sys::BytecodeFileType:
+    case sys::CompressedBytecodeFileType:
+      // LLVM ".so" file.
+      if (LinkInFile(Pathname))
+        return error("Cannot link file '" + Pathname.toString() + "'");
+      is_file = true;
+      break;
+    case sys::ArchiveFileType:
+      if (LinkInArchive(Pathname))
+        return error("Cannot link archive '" + Pathname.toString() + "'");
+      break;
+    default:
+      return warning("Supposed library '" + Lib + "' isn't a library.");
   }
   return false;
 }
@@ -85,8 +102,9 @@ bool Linker::LinkInLibrary(const std::string& Lib) {
 bool Linker::LinkInLibraries(const std::vector<std::string> &Libraries) {
 
   // Process the set of libraries we've been provided.
+  bool is_bytecode;
   for (unsigned i = 0; i < Libraries.size(); ++i)
-    if (LinkInLibrary(Libraries[i]))
+    if (LinkInLibrary(Libraries[i], is_bytecode))
       return true;
 
   // At this point we have processed all the libraries provided to us. Since
@@ -97,7 +115,7 @@ bool Linker::LinkInLibraries(const std::vector<std::string> &Libraries) {
   const Module::LibraryListType& DepLibs = Composite->getLibraries();
   for (Module::LibraryListType::const_iterator I = DepLibs.begin(),
          E = DepLibs.end(); I != E; ++I)
-    if (LinkInLibrary(*I))
+    if (LinkInLibrary(*I, is_bytecode))
       return true;
 
   return false;

tools/gccld/gccld.cpp

@@ -243,11 +243,23 @@ int main(int argc, char **argv, char **envp ) {
     } else {
       // Build a list of the items from our command line
       Linker::ItemList Items;
+      Linker::ItemList NativeItems;
       BuildLinkItems(Items, InputFilenames, Libraries);
 
       // Link all the items together
-      if (TheLinker.LinkInItems(Items))
+      if (TheLinker.LinkInItems(Items,NativeItems))
         return 1; // Error already printed
+
+      // Revise the Libraries based on the remaining (native) libraries that
+      // were not linked in to the bytecode. This ensures that we don't attempt
+      // to pass a bytecode library to the native linker
+      Libraries.clear(); // we've consumed the libraries except for native
+      if ((Native || NativeCBE) && !NativeItems.empty()) {
+        for (Linker::ItemList::const_iterator I = NativeItems.begin(), 
+             E = NativeItems.end(); I != E; ++I) {
+          Libraries.push_back(I->first);
+        }
+      }
     }
 
     // We're done with the Linker, so tell it to release its module

tools/llvm-ld/llvm-ld.cpp

@@ -434,10 +434,11 @@ int main(int argc, char **argv, char **envp) {
     } else {
       // Build a list of the items from our command line
       Linker::ItemList Items;
+      Linker::ItemList NativeItems;
       BuildLinkItems(Items, InputFilenames, Libraries);
 
       // Link all the items together
-      if (TheLinker.LinkInItems(Items) )
+      if (TheLinker.LinkInItems(Items,NativeItems) )
         return 1;
     }