[llvm-objcopy] Add support of symbol modification flags for MachO

llvm/lib/ObjCopy/ConfigManager.cpp

@@ -36,11 +36,9 @@ Expected<const COFFConfig &> ConfigManager::getCOFFConfig() const {
 
 Expected<const MachOConfig &> ConfigManager::getMachOConfig() const {
   if (!Common.SplitDWO.empty() || !Common.SymbolsPrefix.empty() ||
-      !Common.SymbolsPrefixRemove.empty() || !Common.SymbolsToSkip.empty() ||
+      !Common.SymbolsPrefixRemove.empty() ||
       !Common.AllocSectionsPrefix.empty() || !Common.KeepSection.empty() ||
-      !Common.SymbolsToGlobalize.empty() || !Common.SymbolsToKeep.empty() ||
-      !Common.SymbolsToLocalize.empty() ||
-      !Common.SymbolsToKeepGlobal.empty() || !Common.SectionsToRename.empty() ||
+      !Common.SymbolsToKeep.empty() || !Common.SectionsToRename.empty() ||
       !Common.UnneededSymbolsToRemove.empty() ||
       !Common.SetSectionAlignment.empty() || !Common.SetSectionFlags.empty() ||
       !Common.SetSectionType.empty() || Common.ExtractDWO ||

llvm/lib/ObjCopy/MachO/MachOObjcopy.cpp

@@ -93,19 +93,38 @@ static void markSymbols(const CommonConfig &, Object &Obj) {
 static void updateAndRemoveSymbols(const CommonConfig &Config,
                                    const MachOConfig &MachOConfig,
                                    Object &Obj) {
-  for (SymbolEntry &Sym : Obj.SymTable) {
-    // Weaken symbols first to match ELFObjcopy behavior.
-    bool IsExportedAndDefined =
-        (Sym.n_type & llvm::MachO::N_EXT) &&
-        (Sym.n_type & llvm::MachO::N_TYPE) != llvm::MachO::N_UNDF;
-    if (IsExportedAndDefined &&
+  Obj.SymTable.updateSymbols([&](SymbolEntry &Sym) {
+    if (Config.SymbolsToSkip.matches(Sym.Name))
+      return;
+
+    if (!Sym.isUndefinedSymbol() && Config.SymbolsToLocalize.matches(Sym.Name))
+      Sym.n_type &= ~llvm::MachO::N_EXT;
+
+    // Note: these two globalize flags have very similar names but different
+    // meanings:
+    //
+    // --globalize-symbol: promote a symbol to global
+    // --keep-global-symbol: all symbols except for these should be made local
+    //
+    // If --globalize-symbol is specified for a given symbol, it will be
+    // global in the output file even if it is not included via
+    // --keep-global-symbol. Because of that, make sure to check
+    // --globalize-symbol second.
+    if (!Sym.isUndefinedSymbol() && !Config.SymbolsToKeepGlobal.empty() &&
+        !Config.SymbolsToKeepGlobal.matches(Sym.Name))
+      Sym.n_type &= ~llvm::MachO::N_EXT;
+
+    if (!Sym.isUndefinedSymbol() && Config.SymbolsToGlobalize.matches(Sym.Name))
+      Sym.n_type |= llvm::MachO::N_EXT;
+
+    if (Sym.isExternalSymbol() && !Sym.isUndefinedSymbol() &&
         (Config.Weaken || Config.SymbolsToWeaken.matches(Sym.Name)))
       Sym.n_desc |= llvm::MachO::N_WEAK_DEF;
 
     auto I = Config.SymbolsToRename.find(Sym.Name);
     if (I != Config.SymbolsToRename.end())
       Sym.Name = std::string(I->getValue());
-  }
+  });
 
   auto RemovePred = [&Config, &MachOConfig,
                      &Obj](const std::unique_ptr<SymbolEntry> &N) {

llvm/lib/ObjCopy/MachO/MachOObject.cpp

@@ -33,6 +33,19 @@ SymbolEntry *SymbolTable::getSymbolByIndex(uint32_t Index) {
       static_cast<const SymbolTable *>(this)->getSymbolByIndex(Index));
 }
 
+void SymbolTable::updateSymbols(function_ref<void(SymbolEntry &)> Callable) {
+  for (auto &Sym : Symbols)
+    Callable(*Sym);
+
+  // Partition symbols: local < defined external < undefined external.
+  auto it_ext = std::stable_partition(
+      std::begin(Symbols), std::end(Symbols),
+      [](const auto &Sym) { return Sym->isLocalSymbol(); });
+  std::stable_partition(it_ext, std::end(Symbols), [](const auto &Sym) {
+    return !Sym->isUndefinedSymbol();
+  });
+}
+
 void SymbolTable::removeSymbols(
     function_ref<bool(const std::unique_ptr<SymbolEntry> &)> ToRemove) {
   llvm::erase_if(Symbols, ToRemove);

llvm/lib/ObjCopy/MachO/MachOObject.h

@@ -142,6 +142,7 @@ struct SymbolTable {
 
   const SymbolEntry *getSymbolByIndex(uint32_t Index) const;
   SymbolEntry *getSymbolByIndex(uint32_t Index);
+  void updateSymbols(function_ref<void(SymbolEntry &)> Callable);
   void removeSymbols(
       function_ref<bool(const std::unique_ptr<SymbolEntry> &)> ToRemove);
 };

llvm/test/tools/llvm-objcopy/MachO/globalize-symbol.test

@@ -0,0 +1,150 @@
+# RUN: yaml2obj %s -o %t
+# RUN: llvm-objcopy --wildcard --globalize-symbol="*" %t %t.copy
+# RUN: llvm-readobj --symbols %t.copy | FileCheck %s
+
+# CHECK: Symbols [
+# CHECK-NEXT:   Symbol {
+# CHECK-NEXT:     Name: _PrivateSymbol
+# CHECK-NEXT:     Extern
+# CHECK-NEXT:     Type: Section (0xE)
+# CHECK-NEXT:     Section: __text (0x1)
+# CHECK-NEXT:     RefType: UndefinedNonLazy (0x0)
+# CHECK-NEXT:     Flags [ (0x0)
+# CHECK-NEXT:     ]
+# CHECK-NEXT:     Value: 0x1
+# CHECK-NEXT:   }
+# CHECK-NEXT:   Symbol {
+# CHECK-NEXT:     Name: _PrivateExternalSymbol
+# CHECK-NEXT:     PrivateExtern
+# CHECK-NEXT:     Extern
+# CHECK-NEXT:     Type: Section (0xE)
+# CHECK-NEXT:     Section: __text (0x1)
+# CHECK-NEXT:     RefType: UndefinedNonLazy (0x0)
+# CHECK-NEXT:     Flags [ (0x0)
+# CHECK-NEXT:     ]
+# CHECK-NEXT:     Value: 0x2
+# CHECK-NEXT:   }
+# CHECK-NEXT:   Symbol {
+# CHECK-NEXT:     Name: _CommonSymbol
+# CHECK-NEXT:     Extern
+# CHECK-NEXT:     Type: Section (0xE)
+# CHECK-NEXT:     Section: __text (0x1)
+# CHECK-NEXT:     RefType: UndefinedNonLazy (0x0)
+# CHECK-NEXT:     Flags [ (0x0)
+# CHECK-NEXT:     ]
+# CHECK-NEXT:     Value: 0x3
+# CHECK-NEXT:   }
+# CHECK-NEXT:   Symbol {
+# CHECK-NEXT:     Name: _UndefinedExternalSymbol
+# CHECK-NEXT:     Extern
+# CHECK-NEXT:     Type: Undef (0x0)
+# CHECK-NEXT:     Section:  (0x0)
+# CHECK-NEXT:     RefType: UndefinedNonLazy (0x0)
+# CHECK-NEXT:     Flags [ (0x0)
+# CHECK-NEXT:     ]
+# CHECK-NEXT:     Value: 0x0
+# CHECK-NEXT:   }
+# CHECK-NEXT: ]
+
+--- !mach-o
+FileHeader:
+  magic:           0xFEEDFACF
+  cputype:         0x100000C
+  cpusubtype:      0x0
+  filetype:        0x2
+  ncmds:           4
+  sizeofcmds:      328
+  flags:           0x200085
+  reserved:        0x0
+LoadCommands:
+  - cmd:             LC_SEGMENT_64
+    cmdsize:         152
+    segname:         __TEXT
+    vmaddr:          4294967296
+    vmsize:          4096
+    fileoff:         0
+    filesize:        4096
+    maxprot:         5
+    initprot:        5
+    nsects:          1
+    flags:           0
+    Sections:
+      - sectname:        __text
+        segname:         __TEXT
+        addr:            0x100000FF8
+        size:            8
+        offset:          0xFF8
+        align:           2
+        reloff:          0x0
+        nreloc:          0
+        flags:           0x80000400
+        reserved1:       0x0
+        reserved2:       0x0
+        reserved3:       0x0
+        content:         00008052C0035FD6
+  - cmd:             LC_SEGMENT_64
+    cmdsize:         72
+    segname:         __LINKEDIT
+    vmaddr:          4294971392
+    vmsize:          4096
+    fileoff:         4096
+    filesize:        147
+    maxprot:         1
+    initprot:        1
+    nsects:          0
+    flags:           0
+  - cmd:             LC_SYMTAB
+    cmdsize:         24
+    symoff:          4096
+    nsyms:           4
+    stroff:          4164
+    strsize:         79
+  - cmd:             LC_DYSYMTAB
+    cmdsize:         80
+    ilocalsym:       0
+    nlocalsym:       1
+    iextdefsym:      1
+    nextdefsym:      1
+    iundefsym:       1
+    nundefsym:       1
+    tocoff:          0
+    ntoc:            0
+    modtaboff:       0
+    nmodtab:         0
+    extrefsymoff:    0
+    nextrefsyms:     0
+    indirectsymoff:  0
+    nindirectsyms:   0
+    extreloff:       0
+    nextrel:         0
+    locreloff:       0
+    nlocrel:         0
+LinkEditData:
+  NameList:
+    - n_strx:          2
+      n_type:          0x0E
+      n_sect:          1
+      n_desc:          0
+      n_value:         1
+    - n_strx:          17
+      n_type:          0x1E
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+    - n_strx:          54
+      n_type:          0x01
+      n_sect:          0
+      n_desc:          0
+      n_value:         0
+  StringTable:
+    - ' '
+    - _PrivateSymbol
+    - _PrivateExternalSymbol
+    - _CommonSymbol
+    - _UndefinedExternalSymbol
+...