Improve error message for -thinlto-object-suffix-replace and simplify code.

llvm-svn: 332643

lld/ELF/InputFiles.cpp

@@ -1024,22 +1024,21 @@ BitcodeFile::BitcodeFile(MemoryBufferRef MB, StringRef ArchiveName,
     : InputFile(BitcodeKind, MB) {
   this->ArchiveName = ArchiveName;
 
-  // Here we pass a new MemoryBufferRef which is identified by ArchiveName
-  // (the fully resolved path of the archive) + member name + offset of the
-  // member in the archive.
-  // ThinLTO uses the MemoryBufferRef identifier to access its internal
-  // data structures and if two archives define two members with the same name,
-  // this causes a collision which result in only one of the objects being
-  // taken into consideration at LTO time (which very likely causes undefined
-  // symbols later in the link stage).
   std::string Path = MB.getBufferIdentifier().str();
   if (Config->ThinLTOIndexOnly)
-    Path = updateSuffixInPath(MB.getBufferIdentifier());
+    Path = replaceThinLTOSuffix(MB.getBufferIdentifier());
 
+  // ThinLTO assumes that all MemoryBufferRefs given to it have a unique
+  // name. If two archives define two members with the same name, this
+  // causes a collision which result in only one of the objects being taken
+  // into consideration at LTO time (which very likely causes undefined
+  // symbols later in the link stage). So we append file offset to make
+  // filename unique.
   MemoryBufferRef MBRef(
       MB.getBuffer(),
       Saver.save(ArchiveName + Path +
                  (ArchiveName.empty() ? "" : utostr(OffsetInArchive))));
+
   Obj = CHECK(lto::InputFile::create(MBRef), this);
 
   Triple T(Obj->getTargetTriple());
@@ -1242,6 +1241,18 @@ template <class ELFT> void LazyObjFile::addElfSymbols() {
   }
 }
 
+std::string elf::replaceThinLTOSuffix(StringRef Path) {
+  StringRef Suffix = Config->ThinLTOObjectSuffixReplace.first;
+  StringRef Repl = Config->ThinLTOObjectSuffixReplace.second;
+
+  if (!Path.endswith(Suffix)) {
+    error("-thinlto-object-suffix-replace=" + Suffix + ";" + Repl +
+          " was given, but " + Path + " does not ends with the suffix");
+    return "";
+  }
+  return (Path.drop_back(Suffix.size()) + Repl).str();
+}
+
 template void ArchiveFile::parse<ELF32LE>();
 template void ArchiveFile::parse<ELF32BE>();
 template void ArchiveFile::parse<ELF64LE>();

lld/ELF/InputFiles.h

@@ -355,19 +355,7 @@ inline bool isBitcode(MemoryBufferRef MB) {
   return identify_magic(MB.getBuffer()) == llvm::file_magic::bitcode;
 }
 
-inline std::string updateSuffixInPath(llvm::StringRef Path) {
-  if (Path.endswith(Config->ThinLTOObjectSuffixReplace.first)) {
-    size_t pos = Path.rfind(Config->ThinLTOObjectSuffixReplace.first);
-    std::string SuffixedPath =
-        (Path.str().substr(0, pos) +
-         Config->ThinLTOObjectSuffixReplace.second.str());
-    return SuffixedPath;
-  } else {
-    error("cannot find suffix " +
-          Config->ThinLTOObjectSuffixReplace.first.str());
-    return "";
-  }
-}
+std::string replaceThinLTOSuffix(StringRef Path);
 
 extern std::vector<BinaryFile *> BinaryFiles;
 extern std::vector<BitcodeFile *> BitcodeFiles;

lld/ELF/LTO.cpp

@@ -221,11 +221,28 @@ void BitcodeCompiler::add(BitcodeFile &F) {
   checkError(LTOObj->add(std::move(F.Obj), Resols));
 }
 
+static void createEmptyIndex(StringRef ModulePath) {
+  std::string Path = replaceThinLTOSuffix(getThinLTOOutputFile(ModulePath));
+  if (Path.empty())
+    return;
+
+  std::unique_ptr<raw_fd_ostream> OS = openFile(Path + ".thinlto.bc");
+  if (!OS)
+    return;
+
+  ModuleSummaryIndex M(false);
+  M.setSkipModuleByDistributedBackend();
+  WriteIndexToFile(M, *OS);
+
+  if (Config->ThinLTOEmitImportsFiles)
+    openFile(Path + ".imports");
+}
+
 // Merge all the bitcode files we have seen, codegen the result
 // and return the resulting ObjectFile(s).
 std::vector<InputFile *> BitcodeCompiler::compile() {
   unsigned MaxTasks = LTOObj->getMaxTasks();
-  Buff.resize(MaxTasks);
+  Buf.resize(MaxTasks);
   Files.resize(MaxTasks);
 
   // The --thinlto-cache-dir option specifies the path to a directory in which
@@ -242,7 +259,7 @@ std::vector<InputFile *> BitcodeCompiler::compile() {
   checkError(LTOObj->run(
       [&](size_t Task) {
         return llvm::make_unique<lto::NativeObjectStream>(
-            llvm::make_unique<raw_svector_ostream>(Buff[Task]));
+            llvm::make_unique<raw_svector_ostream>(Buf[Task]));
       },
       Cache));
 
@@ -262,26 +279,12 @@ std::vector<InputFile *> BitcodeCompiler::compile() {
   // This is needed because this is what GNU gold plugin does and we have a
   // distributed build system that depends on that behavior.
   if (Config->ThinLTOIndexOnly) {
-    for (LazyObjFile *F : LazyObjFiles) {
-      if (F->AddedToLink || !isBitcode(F->MB))
-        continue;
-
-      std::string Path = updateSuffixInPath(getThinLTOOutputFile(F->getName()));
-
-      std::unique_ptr<raw_fd_ostream> OS = openFile(Path + ".thinlto.bc");
-      if (!OS)
-        continue;
-
-      ModuleSummaryIndex M(false);
-      M.setSkipModuleByDistributedBackend();
-      WriteIndexToFile(M, *OS);
-
-      if (Config->ThinLTOEmitImportsFiles)
-        openFile(Path + ".imports");
-    }
+    for (LazyObjFile *F : LazyObjFiles)
+      if (!F->AddedToLink && isBitcode(F->MB))
+        createEmptyIndex(F->getName());
 
     if (!Config->LTOObjPath.empty())
-      saveBuffer(Buff[0], Config->LTOObjPath);
+      saveBuffer(Buf[0], Config->LTOObjPath);
 
     // ThinLTO with index only option is required to generate only the index
     // files. After that, we exit from linker and ThinLTO backend runs in a
@@ -290,20 +293,21 @@ std::vector<InputFile *> BitcodeCompiler::compile() {
       IndexFile->close();
     return {};
   }
+
   if (!Config->ThinLTOCacheDir.empty())
     pruneCache(Config->ThinLTOCacheDir, Config->ThinLTOCachePolicy);
 
   std::vector<InputFile *> Ret;
   for (unsigned I = 0; I != MaxTasks; ++I) {
-    if (Buff[I].empty())
+    if (Buf[I].empty())
       continue;
     if (Config->SaveTemps) {
       if (I == 0)
-        saveBuffer(Buff[I], Config->OutputFile + ".lto.o");
+        saveBuffer(Buf[I], Config->OutputFile + ".lto.o");
       else
-        saveBuffer(Buff[I], Config->OutputFile + Twine(I) + ".lto.o");
+        saveBuffer(Buf[I], Config->OutputFile + Twine(I) + ".lto.o");
     }
-    InputFile *Obj = createObjectFile(MemoryBufferRef(Buff[I], "lto.tmp"));
+    InputFile *Obj = createObjectFile(MemoryBufferRef(Buf[I], "lto.tmp"));
     Ret.push_back(Obj);
   }
 

lld/ELF/LTO.h

@@ -51,7 +51,7 @@ public:
 
 private:
   std::unique_ptr<llvm::lto::LTO> LTOObj;
-  std::vector<SmallString<0>> Buff;
+  std::vector<SmallString<0>> Buf;
   std::vector<std::unique_ptr<MemoryBuffer>> Files;
   llvm::DenseSet<StringRef> UsedStartStop;
   std::unique_ptr<llvm::raw_fd_ostream> IndexFile;

lld/test/ELF/lto/thinlto-object-suffix-replace.ll

@@ -34,8 +34,7 @@
 ; RUN: not ld.lld -m elf_x86_64 --plugin-opt=thinlto-index-only \
 ; RUN: --plugin-opt=thinlto-object-suffix-replace=".abc;.o" -shared %t1.thinlink.bc \
 ; RUN: -o %t3 2>&1 | FileCheck %s --check-prefix=ERR2
-; ERR2: cannot find suffix .abc
-
+; ERR2: error: -thinlto-object-suffix-replace=.abc;.o was given, but {{.*}} does not ends with the suffix
 
 target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"