[llvm-objcopy] Implement -G/--keep-global-symbol(s).

Summary:
Port GNU Objcopy -G/--keep-global-symbol(s).

This is slightly different than the already-implemented --globalize-symbol, which marks a symbol as global when copying. When --keep-global-symbol (alias -G) is used, *only* those symbols marked will stay global, and all other globals are demoted to local. (Also note that it doesn't *promote* a symbol to global). Additionally, there is a pluralized version of the flag --keep-global-symbols, which effectively applies --keep-global-symbol for every non-comment in a file.

Reviewers: jakehehrlich, jhenderson, alexshap

Reviewed By: jhenderson

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D50589

llvm-svn: 340105

1 files changed, 18 insertions, 0 deletions

diff --git a/llvm/tools/llvm-objcopy/ObjcopyOpts.td b/llvm/tools/llvm-objcopy/ObjcopyOpts.td
index 8cdef453b74..c34494736c3 100644
--- a/llvm/tools/llvm-objcopy/ObjcopyOpts.td
+++ b/llvm/tools/llvm-objcopy/ObjcopyOpts.td
@@ -81,6 +81,24 @@ def L : JoinedOrSeparate<["-"], "L">,
 defm globalize_symbol : Eq<"globalize-symbol">,
                        MetaVarName<"symbol">,
                        HelpText<"Mark <symbol> as global">;
+
+defm keep_global_symbol
+    : Eq<"keep-global-symbol">,
+      MetaVarName<"symbol">,
+      HelpText<"Convert all symbols except <symbol> to local. May be repeated "
+               "to convert all except a set of symbols to local.">;
+def G : JoinedOrSeparate<[ "-" ], "G">, Alias<keep_global_symbol>;
+
+defm keep_global_symbols
+    : Eq<"keep-global-symbols">,
+      MetaVarName<"filename">,
+      HelpText<
+          "Reads a list of symbols from <filename> and runs as if "
+	  "--keep-global-symbol=<symbol> is set for each one. <filename> "
+	  "contains one symbol per line and may contain comments beginning "
+	  "with '#'. Leading and trailing whitespace is stripped from each "
+	  "line. May be repeated to read symbols from many files.">;
+
 defm weaken_symbol : Eq<"weaken-symbol">,
                        MetaVarName<"symbol">,
                        HelpText<"Mark <symbol> as weak">;