Fix handling of mach header and DSO handle symbols.

The magic file which contained these symbols inherited from archive
which meant that the resolver didn't add the required atoms as archive
members only get added when referenced.  Instead we now inherit from
SimpleFile which always links in the atoms needed.

The second issue was in the handling of these symbols when we emit
the MachO.  The mach header symbol needs to be in the atom list as
it gets an offset (0), and being in the atom list makes sure it is
emitted to the symbol table.  DSO handles are not emitted to the
symbol table.

rdar://problem/24450654

llvm-svn: 259574

diff --git a/lld/include/lld/Core/DefinedAtom.h b/lld/include/lld/Core/DefinedAtom.h
index 70fd60d..8406806 100644 (file)
--- a/lld/include/lld/Core/DefinedAtom.h
+++ b/lld/include/lld/Core/DefinedAtom.h
@@ -147,6 +147,7 @@ public:
     typeTLVInitialZeroFill, // TLV initial zero fill data [Darwin]
     typeTLVInitializerPtr,  // pointer to thread local initializer [Darwin]
     typeMachHeader,         // atom representing mach_header [Darwin]
+    typeDSOHandle,          // atom representing DSO handle [Darwin]
     typeThreadZeroFill,     // Uninitialized thread local data(TBSS) [ELF]
     typeThreadData,         // Initialized thread local data(TDATA) [ELF]
     typeRONote,             // Identifies readonly note sections [ELF]

diff --git a/lld/include/lld/Core/File.h b/lld/include/lld/Core/File.h
index d902db3..83b2fea 100644 (file)
--- a/lld/include/lld/Core/File.h
+++ b/lld/include/lld/Core/File.h
@@ -50,6 +50,7 @@ public:
     kindMachObject,           ///< a MachO object file (.o)
     kindELFObject,            ///< a ELF object file (.o)
     kindCEntryObject,         ///< a file for CEntries
+    kindHeaderObject,         ///< a file for file headers
     kindEntryObject,          ///< a file for the entry
     kindUndefinedSymsObject,  ///< a file for undefined symbols
     kindAliasSymsObject,      ///< a file for alias symbols

diff --git a/lld/lib/Core/DefinedAtom.cpp b/lld/lib/Core/DefinedAtom.cpp
index 1e56f66..35596e6 100644 (file)
--- a/lld/lib/Core/DefinedAtom.cpp
+++ b/lld/lib/Core/DefinedAtom.cpp
@@ -79,6 +79,7 @@ DefinedAtom::ContentPermissions DefinedAtom::permissions(ContentType type) {
   case typeUnknown:
   case typeTempLTO:
   case typeSectCreate:
+  case typeDSOHandle:
     return permUnknown;
   }
   llvm_unreachable("unknown content type");

diff --git a/lld/lib/Core/Resolver.cpp b/lld/lib/Core/Resolver.cpp
index 60e5ace..337f6e4 100644 (file)
--- a/lld/lib/Core/Resolver.cpp
+++ b/lld/lib/Core/Resolver.cpp
@@ -343,6 +343,7 @@ bool Resolver::resolveUndefines() {
     case File::kindMachObject:
     case File::kindELFObject:
     case File::kindCEntryObject:
+    case File::kindHeaderObject:
     case File::kindEntryObject:
     case File::kindUndefinedSymsObject:
     case File::kindAliasSymsObject:

diff --git a/lld/lib/ReaderWriter/MachO/ExecutableAtoms.h b/lld/lib/ReaderWriter/MachO/ExecutableAtoms.h
index 620e187..f1dd799 100644 (file)
--- a/lld/lib/ReaderWriter/MachO/ExecutableAtoms.h
+++ b/lld/lib/ReaderWriter/MachO/ExecutableAtoms.h
@@ -11,10 +11,10 @@
 #define LLD_READER_WRITER_MACHO_EXECUTABLE_ATOMS_H
 
 #include "Atoms.h"
+#include "File.h"
 
 #include "llvm/Support/MachO.h"
 
-#include "lld/Core/ArchiveLibraryFile.h"
 #include "lld/Core/DefinedAtom.h"
 #include "lld/Core/File.h"
 #include "lld/Core/LinkingContext.h"
@@ -65,45 +65,57 @@ private:
 // MachHeaderAliasFile lazily instantiates the magic symbols that mark the start
 // of the mach_header for final linked images.
 //
-class MachHeaderAliasFile : public ArchiveLibraryFile {
+class MachHeaderAliasFile : public SimpleFile {
 public:
   MachHeaderAliasFile(const MachOLinkingContext &context)
-      : ArchiveLibraryFile("mach_header symbols") {
-      switch (context.outputMachOType()) {
-      case llvm::MachO::MH_EXECUTE:
-        _machHeaderSymbolName = "__mh_execute_header";
-        break;
-      case llvm::MachO::MH_DYLIB:
-        _machHeaderSymbolName = "__mh_dylib_header";
-        break;
-      case llvm::MachO::MH_BUNDLE:
-        _machHeaderSymbolName = "__mh_bundle_header";
-        break;
-      case llvm::MachO::MH_DYLINKER:
-        _machHeaderSymbolName = "__mh_dylinker_header";
-        break;
-      case llvm::MachO::MH_PRELOAD:
-        _machHeaderSymbolName = "__mh_preload_header";
-        break;
-      default:
-        llvm_unreachable("no mach_header symbol for file type");
-      }
-  }
-
-  std::error_code
-  parseAllMembers(std::vector<std::unique_ptr<File>> &result) override {
-    return std::error_code();
-  }
-
-  File *find(StringRef sym, bool dataSymbolOnly) override {
-    if (sym.equals("___dso_handle") || sym.equals(_machHeaderSymbolName)) {
+    : SimpleFile("mach_header symbols", kindHeaderObject) {
+    StringRef machHeaderSymbolName;
+    StringRef dsoHandleName;
+    switch (context.outputMachOType()) {
+    case llvm::MachO::MH_OBJECT:
+      machHeaderSymbolName = "__mh_object_header";
+      break;
+    case llvm::MachO::MH_EXECUTE:
+      machHeaderSymbolName = "__mh_execute_header";
+      dsoHandleName = "___dso_handle";
+      break;
+    case llvm::MachO::MH_FVMLIB:
+      llvm_unreachable("no mach_header symbol for file type");
+    case llvm::MachO::MH_CORE:
+      llvm_unreachable("no mach_header symbol for file type");
+    case llvm::MachO::MH_PRELOAD:
+      llvm_unreachable("no mach_header symbol for file type");
+    case llvm::MachO::MH_DYLIB:
+      machHeaderSymbolName = "__mh_dylib_header";
+      dsoHandleName = "___dso_handle";
+      break;
+    case llvm::MachO::MH_DYLINKER:
+      machHeaderSymbolName = "__mh_dylinker_header";
+      dsoHandleName = "___dso_handle";
+      break;
+    case llvm::MachO::MH_BUNDLE:
+      machHeaderSymbolName = "__mh_bundle_header";
+      dsoHandleName = "___dso_handle";
+      break;
+    case llvm::MachO::MH_DYLIB_STUB:
+      llvm_unreachable("no mach_header symbol for file type");
+    case llvm::MachO::MH_DSYM:
+      llvm_unreachable("no mach_header symbol for file type");
+    case llvm::MachO::MH_KEXT_BUNDLE:
+      dsoHandleName = "___dso_handle";
+      break;
+    }
+    if (!machHeaderSymbolName.empty())
       _definedAtoms.push_back(new (allocator()) MachODefinedAtom(
-          *this, sym, DefinedAtom::scopeLinkageUnit,
+          *this, machHeaderSymbolName, DefinedAtom::scopeLinkageUnit,
           DefinedAtom::typeMachHeader, DefinedAtom::mergeNo, false, false,
           ArrayRef<uint8_t>(), DefinedAtom::Alignment(4096)));
-      return this;
-    }
-    return nullptr;
+
+    if (!dsoHandleName.empty())
+      _definedAtoms.push_back(new (allocator()) MachODefinedAtom(
+          *this, dsoHandleName, DefinedAtom::scopeLinkageUnit,
+          DefinedAtom::typeDSOHandle, DefinedAtom::mergeNo, false, false,
+          ArrayRef<uint8_t>(), DefinedAtom::Alignment(1)));
   }
 
   const AtomVector<DefinedAtom> &defined() const override {
@@ -124,7 +136,6 @@ public:
 
 private:
   mutable AtomVector<DefinedAtom> _definedAtoms;
-  StringRef _machHeaderSymbolName;
 };
 
 } // namespace mach_o

diff --git a/lld/lib/ReaderWriter/MachO/MachONormalizedFileFromAtoms.cpp b/lld/lib/ReaderWriter/MachO/MachONormalizedFileFromAtoms.cpp
index 22cdede..0d6e188 100644 (file)
--- a/lld/lib/ReaderWriter/MachO/MachONormalizedFileFromAtoms.cpp
+++ b/lld/lib/ReaderWriter/MachO/MachONormalizedFileFromAtoms.cpp
@@ -242,6 +242,7 @@ struct MachOFinalSectionFromAtomType {
 
 const MachOFinalSectionFromAtomType sectsToAtomType[] = {
   ENTRY("__TEXT", "__text",           S_REGULAR,          typeCode),
+  ENTRY("__TEXT", "__text",           S_REGULAR,          typeMachHeader),
   ENTRY("__TEXT", "__cstring",        S_CSTRING_LITERALS, typeCString),
   ENTRY("__TEXT", "__ustring",        S_REGULAR,          typeUTF16String),
   ENTRY("__TEXT", "__const",          S_REGULAR,          typeConstant),
@@ -385,7 +386,12 @@ void Util::processAtomAttributes(const DefinedAtom *atom) {
 }
 
 void Util::assignAtomToSection(const DefinedAtom *atom) {
-  if (atom->contentType() == DefinedAtom::typeMachHeader)
+  if (atom->contentType() == DefinedAtom::typeMachHeader) {
+    _machHeaderAliasAtoms.push_back(atom);
+    // Assign atom to this section with this offset.
+    AtomInfo ai = {atom, 0};
+    sectionForAtom(atom)->atomsAndOffsets.push_back(ai);
+  } else if (atom->contentType() == DefinedAtom::typeDSOHandle)
     _machHeaderAliasAtoms.push_back(atom);
   else
     appendAtom(sectionForAtom(atom), atom);

diff --git a/lld/lib/ReaderWriter/YAML/ReaderWriterYAML.cpp b/lld/lib/ReaderWriter/YAML/ReaderWriterYAML.cpp
index a28237b..3336a3e 100644 (file)
--- a/lld/lib/ReaderWriter/YAML/ReaderWriterYAML.cpp
+++ b/lld/lib/ReaderWriter/YAML/ReaderWriterYAML.cpp
@@ -435,6 +435,7 @@ template <> struct ScalarEnumerationTraits<lld::DefinedAtom::ContentType> {
     io.enumCase(value, "tlv-initializer-ptr",
                                           DefinedAtom::typeTLVInitializerPtr);
     io.enumCase(value, "mach_header",     DefinedAtom::typeMachHeader);
+    io.enumCase(value, "dso_handle",      DefinedAtom::typeDSOHandle);
     io.enumCase(value, "thread-data",     DefinedAtom::typeThreadData);
     io.enumCase(value, "thread-zero-fill",DefinedAtom::typeThreadZeroFill);
     io.enumCase(value, "ro-note",         DefinedAtom::typeRONote);

diff --git a/lld/test/mach-o/arm-interworking-movw.yaml b/lld/test/mach-o/arm-interworking-movw.yaml
index 7e4a2e0..0423ed6 100644 (file)
--- a/lld/test/mach-o/arm-interworking-movw.yaml
+++ b/lld/test/mach-o/arm-interworking-movw.yaml
@@ -2,7 +2,7 @@
 # RUN: lld -flavor darwin -arch armv7 -r -print_atoms %s -o %t  | FileCheck %s
 # RUN: lld -flavor darwin -arch armv7 -dylib -print_atoms %t -o %t2 \
 # RUN:     %p/Inputs/libSystem.yaml -sectalign __TEXT __text 0x1000  | FileCheck %s
-# RUN: llvm-objdump -d -macho %t2 | FileCheck -check-prefix=CODE %s
+# RUN: llvm-objdump -d -macho -no-symbolic-operands %t2 | FileCheck -check-prefix=CODE %s
 #
 # Test thumb and arm branches round trip through -r.
 # Test movw/movt pairs have low bit set properly for thumb vs arm.
@@ -330,7 +330,7 @@ local-symbols:
 # CODE-NEXT:                   movt    r0, #0
 # CODE-NEXT:                   movw    r1, #1
 # CODE-NEXT:                   movt    r1, #0
-# CODE-NEXT:                   movw    r2, _a2
+# CODE-NEXT:                   movw    r2, #4174
 # CODE-NEXT:                   movt    r2, #0
 # CODE-NEXT:                   movw    r3, #42
 # CODE-NEXT:                   movt    r3, #0
@@ -341,7 +341,7 @@ local-symbols:
 # CODE-NEXT:                   movt    r0, #0
 # CODE-NEXT:                   movw    r1, #65495
 # CODE-NEXT:                   movt    r1, #65535
-# CODE-NEXT:                   movw    r2, _a2
+# CODE-NEXT:                   movw    r2, #4174
 # CODE-NEXT:                   movt    r2, #0
 # CODE-NEXT:                   movw    r3, #0
 # CODE-NEXT:                   movt    r3, #0