[MachO] Introduce MinVersion API

[davide]

Summary

Hi,
while introducing support for MinVersionLoadCommand in llvm-readobj I noticed there's no API to extract Major/Minor/Update components conveniently. Currently consumers do the bit twiddling on their own. I think this level of coupling is not necessary. Consumers shouldn't be aware of how version is represented. So, I propose to introduce the following API. I think it can be extended introducing another argument IsSDK (or, simply SDK) so that we can retrieve SDK version components easily as well, without introducing new functions. Comments welcome.

[davide]

+ Kevin Enderby (not on phab).

[• rafael]

Can you include an example of it being used?

[davide]

-> Added usage example, as per Rafael request.
-> Modified the API a little bit.

[• rafael]

LGTM with a nit.

include/llvm/Object/MachO.h

347

These can be static, no?

[grosbach]

Would it be better for these function to be in the header since they're trivial accessors?

[llvm-commits]

r245963.

[grosbach]

Thanks!

[davide]

Sure. I want to point out that large part of the functions in
MachOObjectFile.cpp can be static'ized and moved to the header as they
are very similar to these one.
If nobody else takes care of this task -- I'll audit them and fix once
I'm done with macho-dump removal.

include/llvm/Object/MachO.h

public:
   MachO::segment_command
   getSegmentLoadCommand(const LoadCommandInfo &L) const;
   MachO::segment_command_64
   getSegment64LoadCommand(const LoadCommandInfo &L) const;
   MachO::linker_option_command
   getLinkerOptionLoadCommand(const LoadCommandInfo &L) const;
   MachO::version_min_command
   getVersionMinLoadCommand(const LoadCommandInfo &L) const;
+  uint32_t
+  getVersionMinMajor(MachO::version_min_command &C, bool SDK) const;
+  uint32_t
+  getVersionMinMinor(MachO::version_min_command &C, bool SDK) const;
+  uint32_t
+  getVersionMinUpdate(MachO::version_min_command &C, bool SDK) const;
   MachO::dylib_command
   getDylibIDLoadCommand(const LoadCommandInfo &L) const;
   MachO::dyld_info_command
   getDyldInfoLoadCommand(const LoadCommandInfo &L) const;
   MachO::dylinker_command
   getDylinkerCommand(const LoadCommandInfo &L) const;
   MachO::uuid_command
   getUuidCommand(const LoadCommandInfo &L) const;

lib/Object/MachOObjectFile.cpp

   return getStruct<MachO::linker_option_command>(this, L.Ptr);
 }
 
 MachO::version_min_command
 MachOObjectFile::getVersionMinLoadCommand(const LoadCommandInfo &L) const {
   return getStruct<MachO::version_min_command>(this, L.Ptr);
 }
 
+uint32_t
+MachOObjectFile::getVersionMinMajor(MachO::version_min_command &C,
+                                    bool SDK) const {
+  uint32_t VersionOrSDK = (SDK) ? C.sdk : C.version;
+  return (VersionOrSDK >> 16) & 0xffff;
+}
+
+uint32_t
+MachOObjectFile::getVersionMinMinor(MachO::version_min_command &C,
+                                    bool SDK) const {
+  uint32_t VersionOrSDK = (SDK) ? C.sdk : C.version;
+  return (VersionOrSDK >> 8) & 0xff;
+}
+
+uint32_t
+MachOObjectFile::getVersionMinUpdate(MachO::version_min_command &C,
+                                     bool SDK) const {
+  uint32_t VersionOrSDK = (SDK) ? C.sdk : C.version;
+  return VersionOrSDK & 0xff;
+}
+
 MachO::dylib_command
 MachOObjectFile::getDylibIDLoadCommand(const LoadCommandInfo &L) const {
   return getStruct<MachO::dylib_command>(this, L.Ptr);
 }
 
 MachO::dyld_info_command
 MachOObjectFile::getDyldInfoLoadCommand(const LoadCommandInfo &L) const {
   return getStruct<MachO::dyld_info_command>(this, L.Ptr);

tools/llvm-objdump/MachODump.cpp

   if (rpath.path >= rpath.cmdsize)
     outs() << "         path ?(bad offset " << rpath.path << ")\n";
   else {
     const char *P = (const char *)(Ptr) + rpath.path;
     outs() << "         path " << P << " (offset " << rpath.path << ")\n";
   }
 }
 
-static void PrintVersionMinLoadCommand(MachO::version_min_command vd) {
+static void PrintVersionMinLoadCommand(const MachOObjectFile *Obj,
+                                       MachO::version_min_command vd) {
   if (vd.cmd == MachO::LC_VERSION_MIN_MACOSX)
     outs() << "      cmd LC_VERSION_MIN_MACOSX\n";
   else if (vd.cmd == MachO::LC_VERSION_MIN_IPHONEOS)
     outs() << "      cmd LC_VERSION_MIN_IPHONEOS\n";
   else
     outs() << "      cmd " << vd.cmd << " (?)\n";
   outs() << "  cmdsize " << vd.cmdsize;
   if (vd.cmdsize != sizeof(struct MachO::version_min_command))
     outs() << " Incorrect size\n";
   else
     outs() << "\n";
-  outs() << "  version " << ((vd.version >> 16) & 0xffff) << "."
-         << ((vd.version >> 8) & 0xff);
-  if ((vd.version & 0xff) != 0)
-    outs() << "." << (vd.version & 0xff);
+  outs() << "  version "
+         << Obj->getVersionMinMajor(vd, false) << "."
+         << Obj->getVersionMinMinor(vd, false);
+  uint32_t Update = Obj->getVersionMinUpdate(vd, false);
+  if (Update != 0)
+    outs() << "." << Update;
   outs() << "\n";
   if (vd.sdk == 0)
     outs() << "      sdk n/a";
   else {
-    outs() << "      sdk " << ((vd.sdk >> 16) & 0xffff) << "."
-           << ((vd.sdk >> 8) & 0xff);
-  }
-  if ((vd.sdk & 0xff) != 0)
-    outs() << "." << (vd.sdk & 0xff);
+    outs() << "      sdk "
+           << Obj->getVersionMinMajor(vd, true) << "."
+           << Obj->getVersionMinMinor(vd, true);
+  }
+  Update = Obj->getVersionMinUpdate(vd, true);
+  if (Update != 0)
+    outs() << "." << Update;
   outs() << "\n";
 }
 
 static void PrintSourceVersionCommand(MachO::source_version_command sd) {
   outs() << "      cmd LC_SOURCE_VERSION\n";
   outs() << "  cmdsize " << sd.cmdsize;
   if (sd.cmdsize != sizeof(struct MachO::source_version_command))
     outs() << " Incorrect size\n";

       MachO::uuid_command Uuid = Obj->getUuidCommand(Command);
       PrintUuidLoadCommand(Uuid);
     } else if (Command.C.cmd == MachO::LC_RPATH) {
       MachO::rpath_command Rpath = Obj->getRpathCommand(Command);
       PrintRpathLoadCommand(Rpath, Command.Ptr);
     } else if (Command.C.cmd == MachO::LC_VERSION_MIN_MACOSX ||
                Command.C.cmd == MachO::LC_VERSION_MIN_IPHONEOS) {
       MachO::version_min_command Vd = Obj->getVersionMinLoadCommand(Command);
-      PrintVersionMinLoadCommand(Vd);
+      PrintVersionMinLoadCommand(Obj, Vd);
     } else if (Command.C.cmd == MachO::LC_SOURCE_VERSION) {
       MachO::source_version_command Sd = Obj->getSourceVersionCommand(Command);
       PrintSourceVersionCommand(Sd);
     } else if (Command.C.cmd == MachO::LC_MAIN) {
       MachO::entry_point_command Ep = Obj->getEntryPointCommand(Command);
       PrintEntryPointCommand(Ep);
     } else if (Command.C.cmd == MachO::LC_ENCRYPTION_INFO) {
       MachO::encryption_info_command Ei =