[PATCH] D39353: [lld] Fix --exclude-libs broken when --whole-archive is used

[Oleg Ranevskyy via Phabricator via llvm-commits]

iid_iunknown created this revision.
iid_iunknown added a project: lld.
Herald added a subscriber: emaste.

**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.


Repository:
  rL LLVM

https://reviews.llvm.org/D39353

Files:
  ELF/Driver.cpp
  test/ELF/exclude-libs.s


Index: test/ELF/exclude-libs.s
===================================================================
--- test/ELF/exclude-libs.s
+++ test/ELF/exclude-libs.s
@@ -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
 
Index: ELF/Driver.cpp
===================================================================
--- ELF/Driver.cpp
+++ ELF/Driver.cpp
@@ -976,15 +976,28 @@
 // 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))
+  for (InputFile *File : Files) {
+    // For archives check if they are in the -exclude-libs list.
+    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;
+    // Use of --whole-archive splits static libraries into separate objects.
+    // To handle this case check if the object originates from a static
+    // library that is to be excluded.
+    } else if (auto *F = dyn_cast<elf::ObjFile<ELFT>>(File)) {
+      if (!F->ArchiveName.empty() &&
+          (All || Libs.count(path::filename(F->ArchiveName))))
+        for (SymbolBody *SymBody : F->getSymbols())
+          if (!SymBody->isLocal())
+            SymBody->symbol()->VersionId = VER_NDX_LOCAL;
+    }
+  }
 }
 
 // Do actual linking. Note that when this function is called,
@@ -1067,7 +1080,7 @@
 
   // Handle the -exclude-libs option.
   if (Args.hasArg(OPT_exclude_libs))
-    excludeLibs(Args, Files);
+    excludeLibs<ELFT>(Args, Files);
 
   // Apply version scripts.
   Symtab->scanVersionScript();


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