[llvm-lipo] Add support for -info with archive files (llvm#155309)

Previously trying to print the info of an archive caused a crash. Now we
correctly report the architecture of the contained object files.

Fixes llvm#41655

Author: keith

llvm/test/tools/llvm-lipo/create-archive-input.test

@@ -10,11 +10,12 @@
 # RUN: llvm-ar cr %t.different_architectures.a %t-i386.o %t-x86_64.o
 # RUN: not llvm-lipo %t.different_architectures.a -create -output /dev/null 2>&1 | FileCheck --check-prefix=ARCHIVE-WITH-DIFFERENT-ARCHS %s
 
-# RUN: llvm-ar cr %t.contains_fat_binary.a %t-universal.o 
+# RUN: llvm-ar cr %t.contains_fat_binary.a %t-universal.o
 # RUN: not llvm-lipo %t.contains_fat_binary.a -create -output /dev/null 2>&1 | FileCheck --check-prefix=ARCHIVE-WITH-FAT-BINARY %s
 
 # RUN: llvm-ar cr %t-i386-lib.a %t-i386.o
 # RUN: llvm-lipo %t-i386-lib.a %t-x86_64.o -create -output %t-i386-x86_64-universal.o
+# RUN: llvm-lipo %t-i386-lib.a -info | FileCheck --check-prefix=INFO-i386 %s
 # RUN: llvm-lipo %t-i386-x86_64-universal.o -info | FileCheck --check-prefix=INFO-i386-x86_64 %s
 # RUN: llvm-lipo %t-i386-x86_64-universal.o -thin i386 -output %t-extracted-i386-lib.a
 # RUN: cmp %t-extracted-i386-lib.a %t-i386-lib.a
@@ -51,4 +52,5 @@
 # ARCHIVE-WITH-DIFFERENT-ARCHS: all members must match
 # ARCHIVE-WITH-FAT-BINARY: fat file (not allowed in an archive)
 #
+# INFO-i386: i386
 # INFO-i386-x86_64: i386 x86_64

llvm/tools/llvm-lipo/llvm-lipo.cpp

@@ -425,6 +425,11 @@ static void printBinaryArchs(LLVMContext &LLVMCtx, const Binary *Binary,
     return;
   }
 
+  if (const auto *A = dyn_cast<Archive>(Binary)) {
+    OS << createSliceFromArchive(LLVMCtx, *A).getArchString() << "\n";
+    return;
+  }
+
   // This should be always the case, as this is tested in readInputBinaries
   const auto *IR = cast<IRObjectFile>(Binary);
   Expected<Slice> SliceOrErr = createSliceFromIR(*IR, 0);
@@ -455,7 +460,8 @@ printInfo(LLVMContext &LLVMCtx, ArrayRef<OwningBinary<Binary>> InputBinaries) {
   for (auto &IB : InputBinaries) {
     const Binary *Binary = IB.getBinary();
     if (!Binary->isMachOUniversalBinary()) {
-      assert(Binary->isMachO() && "expected MachO binary");
+      assert(Binary->isMachO() ||
+             Binary->isArchive() && "expected MachO binary");
       outs() << "Non-fat file: " << Binary->getFileName()
              << " is architecture: ";
       printBinaryArchs(LLVMCtx, Binary, outs());