[llvm-strip] Add -o option to llvm-strip

This diff implements the option -o 
for specifying a file to write the output to.

Test plan: make check-all

Differential revision: https://reviews.llvm.org/D47505

llvm-svn: 333693

Author: alexander-shaposhnikov

llvm/test/tools/llvm-objcopy/strip-all.test

@@ -1,15 +1,26 @@
 # RUN: yaml2obj %s > %t
+# RUN: cp %t %t3
 # RUN: llvm-objcopy --strip-all %t %t2
 # RUN: llvm-readobj -file-headers -sections %t2 | FileCheck %s
 
-# We run yaml2obj again rather than copy %t to avoid interfering
-# with llvm-objcopy's test (which potentially could have corrupted/updated the binary).
+# Verify that the previous llvm-objcopy's run has not modified the input.
+# RUN: cmp %t %t3
 
-# RUN: yaml2obj %s > %t3
 # RUN: llvm-strip %t3 
-# RUN: llvm-readobj -file-headers -sections %t3 | FileCheck %s
 # RUN: cmp %t2 %t3
 
+# RUN: cp %t %t4
+# RUN: llvm-strip %t4 -o %t5
+# RUN: cmp %t2 %t5
+
+# Verify that the previous llvm-strip's run has not modified the input.
+# RUN: cmp %t %t4
+
+# RUN: cp %t %t-should-remain-the-same
+# RUN: llvm-strip %t4 -o %t-should-remain-the-same -o %t-should-be-stripped
+# RUN: cmp %t2 %t-should-be-stripped
+# RUN: cmp %t %t-should-remain-the-same
+
 !ELF
 FileHeader:
   Class:           ELFCLASS64

llvm/tools/llvm-objcopy/StripOpts.td

@@ -7,6 +7,10 @@ multiclass Eq<string name> {
 
 def help : Flag<["-", "--"], "help">;
 
+defm output : Eq<"o">,
+              MetaVarName<"output">,
+              HelpText<"Write output to <file>">;
+
 def strip_debug : Flag<["-", "--"], "strip-debug">,
                   HelpText<"Remove debugging symbols only">;
 

llvm/tools/llvm-objcopy/llvm-objcopy.cpp

@@ -582,7 +582,8 @@ CopyConfig ParseStripOptions(ArrayRef<const char *> ArgsArr) {
 
   CopyConfig Config;
   Config.InputFilename = Positional[0];
-  Config.OutputFilename = Positional[0];
+  Config.OutputFilename =
+      InputArgs.getLastArgValue(STRIP_output, Positional[0]);
 
   // Strip debug info only.
   Config.StripDebug = InputArgs.hasArg(STRIP_strip_debug);