Collect bitcode libfuncs

Author: mysterymath

lld/ELF/Driver.cpp

@@ -2709,7 +2709,19 @@ void LinkerDriver::compileBitcodeFiles(bool skipLinkedOutput) {
   if (!ctx.bitcodeFiles.empty())
     markBuffersAsDontNeed(ctx, skipLinkedOutput);
 
-  ltoObjectFiles = lto->compile();
+  llvm::Triple tt(ctx.bitcodeFiles.front()->obj->getTargetTriple());
+  llvm::BumpPtrAllocator alloc;
+  llvm::StringSaver saver(alloc);
+  SmallVector<const char *> bitcodeLibFuncs;
+  for (const char *libFunc : lto::LTO::getLibFuncSymbols(tt, saver)) {
+    Symbol *sym = ctx.symtab->find(libFunc);
+    if (!sym)
+      continue;
+    if (isa<BitcodeFile>(sym->file))
+      bitcodeLibFuncs.push_back(libFunc);
+  }
+
+  ltoObjectFiles = lto->compile(bitcodeLibFuncs);
   for (auto &file : ltoObjectFiles) {
     auto *obj = cast<ObjFile<ELFT>>(file.get());
     obj->parse(/*ignoreComdats=*/true);

lld/ELF/LTO.cpp

@@ -235,6 +235,8 @@ void BitcodeCompiler::add(BitcodeFile &f) {
     const lto::InputFile::Symbol &objSym = objSyms[i];
     lto::SymbolResolution &r = resols[i];
 
+    dbgs() << sym->
+
     // Ideally we shouldn't check for SF_Undefined but currently IRObjectFile
     // reports two symbols for module ASM defined. Without this check, lld
     // flags an undefined in IR with a definition in ASM as prevailing.
@@ -311,7 +313,8 @@ static void thinLTOCreateEmptyIndexFiles(Ctx &ctx) {
 
 // Merge all the bitcode files we have seen, codegen the result
 // and return the resulting ObjectFile(s).
-SmallVector<std::unique_ptr<InputFile>, 0> BitcodeCompiler::compile() {
+SmallVector<std::unique_ptr<InputFile>, 0>
+BitcodeCompiler::compile(const SmallVector<const char *> &bitcodeLibfuncs) {
   unsigned maxTasks = ltoObj->getMaxTasks();
   buf.resize(maxTasks);
   files.resize(maxTasks);

lld/ELF/LTO.h

@@ -42,7 +42,8 @@ class BitcodeCompiler {
   ~BitcodeCompiler();
 
   void add(BitcodeFile &f);
-  SmallVector<std::unique_ptr<InputFile>, 0> compile();
+  SmallVector<std::unique_ptr<InputFile>, 0>
+  compile(const SmallVector<const char *> &bitcodeLibfuncs);
 
 private:
   Ctx &ctx;