[llvm] add -o flag to llvm-bitcode-strip

Add the -o flag to specify an output path for llvm-bitcode-strip.
This matches the interface to the Xcode bitcode_strip tool.

Reviewed By: jhenderson

Differential Revision: https://reviews.llvm.org/D120731

llvm/test/tools/llvm-objcopy/MachO/bitcode-strip.test

@@ -0,0 +1,44 @@
+## Test output flag is required.
+# RUN: yaml2obj %s -o %t
+# RUN: not llvm-bitcode-strip %t 2>&1 | FileCheck --check-prefix=MISSING-ARG %s
+# RUN: llvm-bitcode-strip %t -o %t2
+# RUN: cmp %t %t2
+
+# MISSING-ARG: llvm-bitcode-strip: error: -o is a required argument
+
+--- !mach-o
+FileHeader:
+  magic:           0xFEEDFACF
+  cputype:         0x01000007
+  cpusubtype:      0x00000003
+  filetype:        0x00000001
+  ncmds:           1
+  sizeofcmds:      152
+  flags:           0x00002000
+  reserved:        0x00000000
+LoadCommands:
+  - cmd:             LC_SEGMENT_64
+    cmdsize:         152
+    segname:         __TEXT
+    vmaddr:          0
+    vmsize:          4
+    fileoff:         184
+    filesize:        4
+    maxprot:         7
+    initprot:        7
+    nsects:          1
+    flags:           0
+    Sections:
+      - sectname:        __text
+        segname:         __TEXT
+        addr:            0x0000000000000000
+        content:         'AABBCCDD'
+        size:            4
+        offset:          184
+        align:           0
+        reloff:          0x00000000
+        nreloc:          0
+        flags:           0x80000400
+        reserved1:       0x00000000
+        reserved2:       0x00000000
+        reserved3:       0x00000000

llvm/tools/llvm-objcopy/BitcodeStripOpts.td

@@ -17,8 +17,11 @@ def help : Flag<["--"], "help">;
 def h : Flag<["-"], "h">, Alias<help>;
 
 def version : Flag<["--"], "version">,
-              HelpText<"Print the version and exit.">;
+              HelpText<"Print the version and exit">;
 
 def V : Flag<["-"], "V">,
         Alias<version>,
         HelpText<"Alias for --version">;
+
+def output : JoinedOrSeparate<["-"], "o">, HelpText<"Write output to <file>">,
+             MetaVarName<"<file>">;

llvm/tools/llvm-objcopy/ObjcopyOptions.cpp

@@ -1221,7 +1221,12 @@ objcopy::parseBitcodeStripOptions(ArrayRef<const char *> ArgsArr) {
                              "llvm-bitcode-strip expects a single input file");
   assert(!Positional.empty());
   Config.InputFilename = Positional[0];
-  Config.OutputFilename = Positional[0];
+
+  if (!InputArgs.hasArg(BITCODE_STRIP_output)) {
+    return createStringError(errc::invalid_argument,
+                             "-o is a required argument");
+  }
+  Config.OutputFilename = InputArgs.getLastArgValue(BITCODE_STRIP_output);
 
   DC.CopyConfigs.push_back(std::move(ConfigMgr));
   return std::move(DC);