[llvm-install-name-tool] Add -delete_all_rpaths option

This diff adds an option to remove all rpaths from a Mach-O binary.

Test plan: make check-all

Differential revision: https://reviews.llvm.org/D88674

docs/CommandGuide/llvm-install-name-tool.rst

@@ -43,6 +43,10 @@ the same `<rpath>` value.
  times to delete multiple rpaths. Throws an error if ``<rpath>`` is not listed in
  the binary.
 
+.. option:: -delete_all_rpaths
+
+  Deletes all rpaths from the binary.
+
 .. option:: --help, -h
 
  Print a summary of command line options.

test/tools/llvm-objcopy/MachO/install-name-tool-delete-rpath.test

@@ -42,6 +42,21 @@
 
 # COMBINED: cannot specify both -add_rpath @executable_b/. and -delete_rpath @executable_b/.
 
+## Remove all RPATHS
+# RUN: yaml2obj %s -o %t2
+# RUN: llvm-install-name-tool -delete_all_rpaths %t2
+# RUN: llvm-objdump -p %t2 | FileCheck %s
+
+# CHECK-NOT: LC_RPATH
+
+## Remove all RPATHS and add a new one.
+# RUN: yaml2obj %s -o %t3
+# RUN: llvm-install-name-tool --delete_all_rpaths -add_rpath @executable_b/. %t3
+# RUN: llvm-objdump -p %t3 | \
+# RUN:   FileCheck %s --check-prefix=DELETE_AND_ADD --implicit-check-not=@executable
+
+# DELETE_AND_ADD: @executable_b/.
+
 --- !mach-o
 FileHeader:
   magic:           0xFEEDFACF

tools/llvm-objcopy/CopyConfig.cpp

@@ -953,6 +953,9 @@ parseInstallNameToolOptions(ArrayRef<const char *> ArgsArr) {
   for (auto *Arg : InputArgs.filtered(INSTALL_NAME_TOOL_change))
     Config.InstallNamesToUpdate.insert({Arg->getValue(0), Arg->getValue(1)});
 
+  Config.RemoveAllRpaths =
+      InputArgs.hasArg(INSTALL_NAME_TOOL_delete_all_rpaths);
+
   SmallVector<StringRef, 2> Positional;
   for (auto Arg : InputArgs.filtered(INSTALL_NAME_TOOL_UNKNOWN))
     return createStringError(errc::invalid_argument, "unknown argument '%s'",

tools/llvm-objcopy/CopyConfig.h

@@ -230,6 +230,9 @@ struct CopyConfig {
   bool StripUnneeded = false;
   bool Weaken = false;
   bool DecompressDebugSections = false;
+  // install-name-tool's --delete_all_rpaths
+  bool RemoveAllRpaths = false;
+
   DebugCompressionType CompressionType = DebugCompressionType::None;
 
   // parseELFConfig performs ELF-specific command-line parsing. Fills `ELF` on

tools/llvm-objcopy/InstallNameToolOpts.td

@@ -21,6 +21,9 @@ def add_rpath : Option<["-", "--"], "add_rpath", KIND_SEPARATE>,
 def delete_rpath: Option<["-", "--"], "delete_rpath", KIND_SEPARATE>,
                   HelpText<"Delete specified rpath">;
 
+def delete_all_rpaths: Flag<["-", "--"], "delete_all_rpaths">,
+              HelpText<"Delete all rpath directives">;
+
 def rpath: MultiArg<["-", "--"], "rpath", 2>,
            HelpText<"Change rpath path name">;
 

tools/llvm-objcopy/MachO/MachOObjcopy.cpp

@@ -137,8 +137,14 @@ static Error processLoadCommands(const CopyConfig &Config, Object &Obj) {
   DenseSet<StringRef> RPathsToRemove(Config.RPathsToRemove.begin(),
                                      Config.RPathsToRemove.end());
 
-  LoadCommandPred RemovePred = [&RPathsToRemove](const LoadCommand &LC) {
+  LoadCommandPred RemovePred = [&RPathsToRemove,
+                                &Config](const LoadCommand &LC) {
     if (LC.MachOLoadCommand.load_command_data.cmd == MachO::LC_RPATH) {
+      // When removing all RPaths we don't need to care
+      // about what it contains
+      if (Config.RemoveAllRpaths)
+        return true;
+
       StringRef RPath = getPayloadString(LC);
       if (RPathsToRemove.count(RPath)) {
         RPathsToRemove.erase(RPath);