commit d332ec9209ac0a54fc4f1e5e4edc7948fcc4d6af
author Alexander Shaposhnikov <alexshap@fb.com> Mon Jun 22 16:49:14 2020 -0700
committer Alexander Shaposhnikov <alexshap@fb.com> Mon Jun 22 16:49:49 2020 -0700
tree ea3daaca274a7f63865032d5e63c6590b7e85e8f
parent 009c9b83acfc8bb863894e349bccc2473c685dbc

[llvm-install-name-tool] Implement delete_rpath option

This diff adds support for deleting an rpath from a Mach-O binary.

Patch by Sameer Arora!

Test plan: make check-all

Differential revision: https://reviews.llvm.org/D81527

llvm/tools/llvm-objcopy/MachO/MachOObjcopy.cpp

diff --git a/llvm/tools/llvm-objcopy/MachO/MachOObjcopy.cpp b/llvm/tools/llvm-objcopy/MachO/MachOObjcopy.cpp
index 17d84549..6a6f5e7 100644
--- a/llvm/tools/llvm-objcopy/MachO/MachOObjcopy.cpp
+++ b/llvm/tools/llvm-objcopy/MachO/MachOObjcopy.cpp
@@ -10,6 +10,7 @@
 #include "../CopyConfig.h"
 #include "MachOReader.h"
 #include "MachOWriter.h"
+#include "llvm/ADT/DenseSet.h"
 #include "llvm/Support/Errc.h"
 #include "llvm/Support/Error.h"
 
@@ -19,6 +20,39 @@
 
 using namespace object;
 using SectionPred = std::function<bool(const std::unique_ptr<Section> &Sec)>;
+using LoadCommandPred = std::function<bool(const LoadCommand &LC)>;
+
+static Error removeLoadCommands(const CopyConfig &Config, Object &Obj) {
+  DenseSet<StringRef> RPathsToRemove(Config.RPathsToRemove.begin(),
+                                     Config.RPathsToRemove.end());
+
+  LoadCommandPred RemovePred = [&RPathsToRemove](const LoadCommand &LC) {
+    if (LC.MachOLoadCommand.load_command_data.cmd == MachO::LC_RPATH) {
+      StringRef RPath =
+          StringRef(reinterpret_cast<const char *>(LC.Payload.data()),
+                    LC.Payload.size())
+              .rtrim('\0');
+      if (RPathsToRemove.count(RPath)) {
+        RPathsToRemove.erase(RPath);
+        return true;
+      }
+    }
+    return false;
+  };
+
+  if (Error E = Obj.removeLoadCommands(RemovePred))
+    return E;
+
+  // Emit an error if the Mach-O binary does not contain an rpath path name
+  // specified in -delete_rpath.
+  for (StringRef RPath : Config.RPathsToRemove) {
+    if (RPathsToRemove.count(RPath))
+      return createStringError(errc::invalid_argument,
+                               "no LC_RPATH load command with path: %s",
+                               RPath.str().c_str());
+  }
+  return Error::success();
+}
 
 static Error removeSections(const CopyConfig &Config, Object &Obj) {
   SectionPred RemovePred = [](const std::unique_ptr<Section> &) {
@@ -220,6 +254,9 @@
       return E;
   }
 
+  if (Error E = removeLoadCommands(Config, Obj))
+    return E;
+
   for (StringRef RPath : Config.RPathToAdd) {
     for (LoadCommand &LC : Obj.LoadCommands) {
       if (LC.MachOLoadCommand.load_command_data.cmd == MachO::LC_RPATH &&

llvm/tools/llvm-objcopy/MachO/Object.cpp

diff --git a/llvm/tools/llvm-objcopy/MachO/Object.cpp b/llvm/tools/llvm-objcopy/MachO/Object.cpp
index 0f28cb0..de8cb0a 100644
--- a/llvm/tools/llvm-objcopy/MachO/Object.cpp
+++ b/llvm/tools/llvm-objcopy/MachO/Object.cpp
@@ -32,6 +32,42 @@
       std::end(Symbols));
 }
 
+void Object::updateLoadCommandIndexes() {
+  // Update indices of special load commands
+  for (size_t Index = 0, Size = LoadCommands.size(); Index < Size; ++Index) {
+    LoadCommand &LC = LoadCommands[Index];
+    switch (LC.MachOLoadCommand.load_command_data.cmd) {
+    case MachO::LC_SYMTAB:
+      SymTabCommandIndex = Index;
+      break;
+    case MachO::LC_DYSYMTAB:
+      DySymTabCommandIndex = Index;
+      break;
+    case MachO::LC_DYLD_INFO:
+    case MachO::LC_DYLD_INFO_ONLY:
+      DyLdInfoCommandIndex = Index;
+      break;
+    case MachO::LC_DATA_IN_CODE:
+      DataInCodeCommandIndex = Index;
+      break;
+    case MachO::LC_FUNCTION_STARTS:
+      FunctionStartsCommandIndex = Index;
+      break;
+    }
+  }
+}
+
+Error Object::removeLoadCommands(
+    function_ref<bool(const LoadCommand &)> ToRemove) {
+  auto It = std::stable_partition(
+      LoadCommands.begin(), LoadCommands.end(),
+      [&](const LoadCommand &LC) { return !ToRemove(LC); });
+  LoadCommands.erase(It, LoadCommands.end());
+
+  updateLoadCommandIndexes();
+  return Error::success();
+}
+
 Error Object::removeSections(
     function_ref<bool(const std::unique_ptr<Section> &)> ToRemove) {
   DenseMap<uint32_t, const Section *> OldIndexToSection;

llvm/tools/llvm-objcopy/MachO/Object.h

diff --git a/llvm/tools/llvm-objcopy/MachO/Object.h b/llvm/tools/llvm-objcopy/MachO/Object.h
index 5da31d2..e825d18 100644
--- a/llvm/tools/llvm-objcopy/MachO/Object.h
+++ b/llvm/tools/llvm-objcopy/MachO/Object.h
@@ -326,6 +326,11 @@
 
   Error
   removeSections(function_ref<bool(const std::unique_ptr<Section> &)> ToRemove);
+
+  Error removeLoadCommands(function_ref<bool(const LoadCommand &)> ToRemove);
+
+  void updateLoadCommandIndexes();
+
   void addLoadCommand(LoadCommand LC);
 
   /// Creates a new segment load command in the object and returns a reference