[llvm-strip] Add --strip-symbol

[jhenderson]

test/tools/llvm-objcopy/ELF/strip-symbol.test

2

Please use a different output file for each test case. Probably easiest is to put this after the llvm-objcopy case and use %t3 instead.

tools/llvm-objcopy/CopyConfig.cpp

437

I'm not sure I like checking InputArgs here, since it looks weird compared to the other cases. Perhaps the better thing to do would be to move this entire if clause to after the for loops, and then check if the SymbolsToRemove vector is empty.

[evgeny777]

Addressed

[rupprecht]

This option exists in objcopy too, can you add it to ObjcopyOpts.td and handle it in the other args parsing block too?

tools/llvm-objcopy/StripOpts.td

55

Nit: looks like this isn't indented right, it should align w/ Eq

Note: clang-format (from trunk) can fix these simple tablegen files, with the exception that it puts in spaces around ["-"] that you have to revert -- try git-clang-format --extensions td --binary ~/build/clang-format master (I'm trying to submit a couple patches to fix that)

[jhenderson]

LGTM, with @rupprecht's fixes.

[rupprecht]

In D57440#1377071, @rupprecht wrote:

This option exists in objcopy too, can you add it to ObjcopyOpts.td and handle it in the other args parsing block too?

I just noticed this is already handled by objcopy, and was just missing from strip.

test/tools/llvm-objcopy/ELF/strip-symbol.test

 # RUN: yaml2obj %s > %t
+# RUN: llvm-strip --strip-symbol baz -N bar %t -o %t2
+# RUN: llvm-readobj --symbols --sections %t2 | FileCheck %s
 # RUN: llvm-objcopy --strip-symbol baz -N bar %t %t2
 # RUN: llvm-readobj --symbols --sections %t2 | FileCheck %s
 
 !ELF
 FileHeader:
   Class:           ELFCLASS64
   Data:            ELFDATA2LSB
   Type:            ET_REL

tools/llvm-objcopy/CopyConfig.cpp

DriverConfig parseStripOptions(ArrayRef<const char *> ArgsArr) {
   Config.StripDebug = InputArgs.hasArg(STRIP_strip_debug);
 
   Config.DiscardAll = InputArgs.hasArg(STRIP_discard_all);
   Config.StripUnneeded = InputArgs.hasArg(STRIP_strip_unneeded);
   Config.StripAll = InputArgs.hasArg(STRIP_strip_all);
   Config.StripAllGNU = InputArgs.hasArg(STRIP_strip_all_gnu);
 
   if (!Config.StripDebug && !Config.StripUnneeded && !Config.DiscardAll &&
-      !Config.StripAllGNU)
+      !Config.StripAllGNU && !InputArgs.hasArg(STRIP_strip_symbol))
     Config.StripAll = true;
 
   for (auto Arg : InputArgs.filtered(STRIP_keep_section))
     Config.KeepSection.push_back(Arg->getValue());
 
   for (auto Arg : InputArgs.filtered(STRIP_remove_section))
     Config.ToRemove.push_back(Arg->getValue());
 
+  for (auto Arg : InputArgs.filtered(STRIP_strip_symbol))
+    Config.SymbolsToRemove.push_back(Arg->getValue());
+
   for (auto Arg : InputArgs.filtered(STRIP_keep_symbol))
     Config.SymbolsToKeep.push_back(Arg->getValue());
 
   Config.DeterministicArchives =
       InputArgs.hasFlag(STRIP_enable_deterministic_archives,
                         STRIP_disable_deterministic_archives, /*default=*/true);
 
   Config.PreserveDates = InputArgs.hasArg(STRIP_preserve_dates);

tools/llvm-objcopy/StripOpts.td

 def S : Flag<["-"], "S">, Alias<strip_debug>;
 def strip_unneeded : Flag<["-", "--"], "strip-unneeded">,
                      HelpText<"Remove all symbols not needed by relocations">;
 
 defm remove_section : Eq<"remove-section", "Remove <section>">,
                       MetaVarName<"section">;
 def R : JoinedOrSeparate<["-"], "R">, Alias<remove_section>;
 
+defm strip_symbol : Eq<"strip-symbol", "Strip <symbol>">,
+                      MetaVarName<"symbol">;
+def N : JoinedOrSeparate<["-"], "N">, Alias<strip_symbol>;
+
 defm keep_section : Eq<"keep-section", "Keep <section>">,
                     MetaVarName<"section">;
 defm keep_symbol : Eq<"keep-symbol", "Do not remove symbol <symbol>">,
                    MetaVarName<"symbol">;
 def K : JoinedOrSeparate<["-"], "K">, Alias<keep_symbol>;
 
 def discard_all
     : Flag<["-", "--"], "discard-all">,
       HelpText<"Remove all local symbols except file and section symbols">;
 def x : Flag<["-"], "x">, Alias<discard_all>;
 
 def version : Flag<["-", "--"], "version">,
               HelpText<"Print the version and exit.">;
 def V : Flag<["-"], "V">, Alias<version>;