[lld-macho] Disambiguate bitcode files with the same name by archive name/offset...

Ported from COFF/ELF; test is adapted from
test/COFF/thinlto-archivecollision.ll

LTO expects every bitcode file to have a unique name. If given multiple bitcode
files with the same name, it errors with "Expected at most one ThinLTO module
per bitcode file".

This change incorporates the archive name, to disambiguate members with the
same name in different archives and the offset in archive to disambiguate
members with the same name in the same archive.

Differential Revision: https://reviews.llvm.org/D106179

diff --git a/lld/MachO/Driver.cpp b/lld/MachO/Driver.cpp
index 4fab867..a8c11b6 100644 (file)
--- a/lld/MachO/Driver.cpp
+++ b/lld/MachO/Driver.cpp
@@ -228,6 +228,7 @@ namespace {
 struct ArchiveMember {
   MemoryBufferRef mbref;
   uint32_t modTime;
+  uint64_t offsetInArchive;
 };
 } // namespace
 
@@ -257,7 +258,7 @@ static std::vector<ArchiveMember> getArchiveMembers(MemoryBufferRef mb) {
         CHECK(c.getLastModified(), mb.getBufferIdentifier() +
                                        ": could not get the modification "
                                        "time for a child of the archive"));
-    v.push_back({mbref, modTime});
+    v.push_back({mbref, modTime, c.getChildOffset()});
   }
   if (err)
     fatal(mb.getBufferIdentifier() +
@@ -298,7 +299,8 @@ static InputFile *addFile(StringRef path, bool forceLoadArchive,
       if (Optional<MemoryBufferRef> buffer = readFile(path)) {
         for (const ArchiveMember &member : getArchiveMembers(*buffer)) {
           if (Optional<InputFile *> file = loadArchiveMember(
-                  member.mbref, member.modTime, path, /*objCOnly=*/false)) {
+                  member.mbref, member.modTime, path, /*objCOnly=*/false,
+                  member.offsetInArchive)) {
             inputFiles.insert(*file);
             printArchiveMemberLoad(
                 (forceLoadArchive ? "-force_load" : "-all_load"),
@@ -319,7 +321,8 @@ static InputFile *addFile(StringRef path, bool forceLoadArchive,
       if (Optional<MemoryBufferRef> buffer = readFile(path)) {
         for (const ArchiveMember &member : getArchiveMembers(*buffer)) {
           if (Optional<InputFile *> file = loadArchiveMember(
-                  member.mbref, member.modTime, path, /*objCOnly=*/true)) {
+                  member.mbref, member.modTime, path, /*objCOnly=*/true,
+                  member.offsetInArchive)) {
             inputFiles.insert(*file);
             printArchiveMemberLoad("-ObjC", inputFiles.back());
           }
@@ -343,7 +346,7 @@ static InputFile *addFile(StringRef path, bool forceLoadArchive,
     }
     break;
   case file_magic::bitcode:
-    newFile = make<BitcodeFile>(mbref);
+    newFile = make<BitcodeFile>(mbref, "", 0);
     break;
   case file_magic::macho_executable:
   case file_magic::macho_bundle:

diff --git a/lld/MachO/Driver.h b/lld/MachO/Driver.h
index 1006cc1..10f307e 100644 (file)
--- a/lld/MachO/Driver.h
+++ b/lld/MachO/Driver.h
@@ -70,7 +70,8 @@ llvm::StringRef rerootPath(llvm::StringRef path);
 
 llvm::Optional<InputFile *> loadArchiveMember(MemoryBufferRef, uint32_t modTime,
                                               StringRef archiveName,
-                                              bool objCOnly);
+                                              bool objCOnly,
+                                              uint64_t offsetInArchive);
 
 uint32_t getModTime(llvm::StringRef path);
 

diff --git a/lld/MachO/DriverUtils.cpp b/lld/MachO/DriverUtils.cpp
index 5f46812..fc25182 100644 (file)
--- a/lld/MachO/DriverUtils.cpp
+++ b/lld/MachO/DriverUtils.cpp
@@ -280,7 +280,8 @@ StringRef macho::rerootPath(StringRef path) {
 Optional<InputFile *> macho::loadArchiveMember(MemoryBufferRef mb,
                                                uint32_t modTime,
                                                StringRef archiveName,
-                                               bool objCOnly) {
+                                               bool objCOnly,
+                                               uint64_t offsetInArchive) {
   if (config->zeroModTime)
     modTime = 0;
 
@@ -291,7 +292,7 @@ Optional<InputFile *> macho::loadArchiveMember(MemoryBufferRef mb,
     return None;
   case file_magic::bitcode:
     if (!objCOnly || check(isBitcodeContainingObjCCategory(mb)))
-      return make<BitcodeFile>(mb);
+      return make<BitcodeFile>(mb, archiveName, offsetInArchive);
     return None;
   default:
     error(archiveName + ": archive member " + mb.getBufferIdentifier() +

diff --git a/lld/MachO/InputFiles.cpp b/lld/MachO/InputFiles.cpp
index e1fc35d..22b74ff 100644 (file)
--- a/lld/MachO/InputFiles.cpp
+++ b/lld/MachO/InputFiles.cpp
@@ -1235,8 +1235,8 @@ void ArchiveFile::fetch(const object::Archive::Symbol &sym) {
   // to it later.
   const object::Archive::Symbol symCopy = sym;
 
-  if (Optional<InputFile *> file =
-          loadArchiveMember(mb, modTime, getName(), /*objCOnly=*/false)) {
+  if (Optional<InputFile *> file = loadArchiveMember(
+          mb, modTime, getName(), /*objCOnly=*/false, c.getChildOffset())) {
     inputFiles.insert(*file);
     // ld64 doesn't demangle sym here even with -demangle.
     // Match that: intentionally don't call toMachOString().
@@ -1275,8 +1275,22 @@ static macho::Symbol *createBitcodeSymbol(const lto::InputFile::Symbol &objSym,
                             /*noDeadStrip=*/false);
 }
 
-BitcodeFile::BitcodeFile(MemoryBufferRef mbref)
-    : InputFile(BitcodeKind, mbref) {
+BitcodeFile::BitcodeFile(MemoryBufferRef mb, StringRef archiveName,
+                         uint64_t offsetInArchive)
+    : InputFile(BitcodeKind, mb) {
+  std::string path = mb.getBufferIdentifier().str();
+  // ThinLTO assumes that all MemoryBufferRefs given to it have a unique
+  // name. If two members with the same name are provided, this causes a
+  // collision and ThinLTO can't proceed.
+  // So, we append the archive name to disambiguate two members with the same
+  // name from multiple different archives, and offset within the archive to
+  // disambiguate two members of the same name from a single archive.
+  MemoryBufferRef mbref(
+      mb.getBuffer(),
+      saver.save(archiveName.empty() ? path
+                                     : archiveName + sys::path::filename(path) +
+                                           utostr(offsetInArchive)));
+
   obj = check(lto::InputFile::create(mbref));
 
   // Convert LTO Symbols to LLD Symbols in order to perform resolution. The

diff --git a/lld/MachO/InputFiles.h b/lld/MachO/InputFiles.h
index 3bf9e77..0101fb7 100644 (file)
--- a/lld/MachO/InputFiles.h
+++ b/lld/MachO/InputFiles.h
@@ -196,7 +196,8 @@ private:
 
 class BitcodeFile final : public InputFile {
 public:
-  explicit BitcodeFile(MemoryBufferRef mb);
+  explicit BitcodeFile(MemoryBufferRef mb, StringRef archiveName,
+                       uint64_t offsetInArchive);
   static bool classof(const InputFile *f) { return f->kind() == BitcodeKind; }
 
   std::unique_ptr<llvm::lto::InputFile> obj;

diff --git a/lld/test/MachO/lto-archivecollision.ll b/lld/test/MachO/lto-archivecollision.ll
new file mode 100644 (file)
index 0000000..03999a4
--- /dev/null
+++ b/lld/test/MachO/lto-archivecollision.ll
@@ -0,0 +1,55 @@
+; RUN: rm -rf %t; split-file %s %t
+; RUN: mkdir %t/a %t/b
+; RUN: opt -thinlto-bc -o %t/main.o %t/main.ll
+; RUN: opt -thinlto-bc -o %t/a/bar.o %t/foo.ll
+; RUN: opt -thinlto-bc -o %t/b/bar.o %t/bar.ll
+; RUN: llvm-ar crs %t/libbar.a %t/a/bar.o %t/b/bar.o
+; RUN: %lld -save-temps %t/main.o %t/libbar.a -o %t/test
+; RUN: FileCheck %s --check-prefix=SAME-ARCHIVE < %t/test.resolution.txt
+
+; RUN: llvm-ar crs %t/liba.a %t/a/bar.o
+; RUN: llvm-ar crs %t/libb.a %t/b/bar.o
+; RUN: %lld -save-temps %t/main.o %t/liba.a %t/libb.a -o %t/test
+; RUN: FileCheck %s --check-prefix=DIFFERENT-ARCHIVES < %t/test.resolution.txt
+
+; SAME-ARCHIVE: libbar.abar.o[[#OFFSET:]]
+; SAME-ARCHIVE-NEXT: -r={{.*}}/libbar.abar.o[[#OFFSET:]],_foo,p
+; SAME-ARCHIVE-NEXT: libbar.abar.o[[#OTHEROFFSET:]]
+; SAME-ARCHIVE-NEXT: -r={{.*}}/libbar.abar.o[[#OTHEROFFSET:]],_bar,p
+
+; DIFFERENT-ARCHIVES: liba.abar.o[[#OFFSET:]]
+; DIFFERENT-ARCHIVES-NEXT: -r={{.*}}/liba.abar.o[[#OFFSET:]],_foo,p
+; DIFFERENT-ARCHIVES-NEXT: libb.abar.o[[#OTHEROFFSET:]]
+; DIFFERENT-ARCHIVES-NEXT: -r={{.*}}/libb.abar.o[[#OTHEROFFSET:]],_bar,p
+
+;--- main.ll
+
+target triple = "x86_64-apple-macosx10.15.0"
+target datalayout = "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+
+declare void @bar()
+declare void @foo()
+
+define i32 @main() {
+  call void @foo()
+  call void @bar()
+  ret i32 0
+}
+
+;--- foo.ll
+
+target triple = "x86_64-apple-macosx10.15.0"
+target datalayout = "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+
+define void @foo() {
+  ret void
+}
+
+;--- bar.ll
+
+target triple = "x86_64-apple-macosx10.15.0"
+target datalayout = "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+
+define void @bar() {
+  ret void
+}