[lld] r316998 - [lld] Fix --exclude-libs broken when --whole-archive is used

[Oleg Ranevskyy via llvm-commits]

Author: oleg
Date: Tue Oct 31 06:51:06 2017
New Revision: 316998

URL: http://llvm.org/viewvc/llvm-project?rev=316998&view=rev
Log:
[lld] Fix --exclude-libs broken when --whole-archive is used

Summary:
**Problem**
`--exclude-libs` does not work for static libraries affected by the `--whole-archive` option.

**Description**
`--exclude-libs` creates a list of static library paths and does library lookups in this list.
`--whole-archive` splits the static libraries that follow it into separate objects. As a result, lld no longer sees static libraries among linked files and does no `--exclude-libs` lookups.

**Solution**
The proposed solution is to make `--exclude-libs` consider object files too. When lld finds an object file it checks whether this file originates from an archive and, if so, looks the archive up in the `--exclude-libs` list.

Reviewers: ruiu, rafael

Reviewed By: ruiu

Subscribers: asl, ikudrin, llvm-commits, emaste

Tags: #lld

Differential Revision: https://reviews.llvm.org/D39353

Modified:
    lld/trunk/ELF/Driver.cpp
    lld/trunk/test/ELF/exclude-libs.s

Modified: lld/trunk/ELF/Driver.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Driver.cpp?rev=316998&r1=316997&r2=316998&view=diff
==============================================================================
--- lld/trunk/ELF/Driver.cpp (original)
+++ lld/trunk/ELF/Driver.cpp Tue Oct 31 06:51:06 2017
@@ -978,21 +978,32 @@ static DenseSet<StringRef> getExcludeLib
   return Ret;
 }
 
+static Optional<StringRef> getArchiveName(InputFile *File) {
+  if (isa<ArchiveFile>(File))
+    return File->getName();
+  if (!File->ArchiveName.empty())
+    return File->ArchiveName;
+  return None;
+}
+
 // Handles the -exclude-libs option. If a static library file is specified
 // by the -exclude-libs option, all public symbols from the archive become
 // private unless otherwise specified by version scripts or something.
 // A special library name "ALL" means all archive files.
 //
 // This is not a popular option, but some programs such as bionic libc use it.
+template <class ELFT>
 static void excludeLibs(opt::InputArgList &Args, ArrayRef<InputFile *> Files) {
   DenseSet<StringRef> Libs = getExcludeLibs(Args);
   bool All = Libs.count("ALL");
 
-  for (InputFile *File : Files)
-    if (auto *F = dyn_cast<ArchiveFile>(File))
-      if (All || Libs.count(path::filename(F->getName())))
-        for (SymbolBody *Sym : F->getSymbols())
-          Sym->symbol()->VersionId = VER_NDX_LOCAL;
+  for (InputFile *File : Files) {
+    if (Optional<StringRef> Archive = getArchiveName(File))
+      if (All || Libs.count(path::filename(*Archive)))
+        for (SymbolBody *SymBody : File->getSymbols())
+          if (!SymBody->isLocal())
+            SymBody->symbol()->VersionId = VER_NDX_LOCAL;
+  }
 }
 
 // Do actual linking. Note that when this function is called,
@@ -1075,7 +1086,7 @@ template <class ELFT> void LinkerDriver:
 
   // Handle the -exclude-libs option.
   if (Args.hasArg(OPT_exclude_libs))
-    excludeLibs(Args, Files);
+    excludeLibs<ELFT>(Args, Files);
 
   // Apply version scripts.
   Symtab->scanVersionScript();

Modified: lld/trunk/test/ELF/exclude-libs.s
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/exclude-libs.s?rev=316998&r1=316997&r2=316998&view=diff
==============================================================================
--- lld/trunk/test/ELF/exclude-libs.s (original)
+++ lld/trunk/test/ELF/exclude-libs.s Tue Oct 31 06:51:06 2017
@@ -22,6 +22,12 @@
 // RUN: ld.lld -shared %t.o %t.dir/exc.a -o %t.exe --exclude-libs=ALL
 // RUN: llvm-readobj -dyn-symbols %t.exe | FileCheck --check-prefix=EXCLUDE %s
 
+// RUN: ld.lld -shared --whole-archive %t.o %t.dir/exc.a -o %t.exe --exclude-libs foo,bar,exc.a
+// RUN: llvm-readobj -dyn-symbols %t.exe | FileCheck --check-prefix=EXCLUDE %s
+
+// RUN: ld.lld -shared --whole-archive %t.o %t.dir/exc.a -o %t.exe --exclude-libs=ALL
+// RUN: llvm-readobj -dyn-symbols %t.exe | FileCheck --check-prefix=EXCLUDE %s
+
 // DEFAULT: Name: fn
 // EXCLUDE-NOT: Name: fn