Add support for the source_version cmdline option.

This is of the form A.B.C.D.E and to match ld64's behaviour, is
always output to files, even when the version is 0.

rdar://problem/24472630

llvm-svn: 259746

lld/include/lld/ReaderWriter/MachOLinkingContext.h

@@ -169,6 +169,9 @@ public:
   uint32_t sdkVersion() const { return _sdkVersion; }
   void setSdkVersion(uint64_t v) { _sdkVersion = v; }
 
+  uint64_t sourceVersion() const { return _sourceVersion; }
+  void setSourceVersion(uint64_t v) { _sourceVersion = v; }
+
   uint32_t swiftVersion() const { return _swiftVersion; }
 
   /// \brief Checks whether a given path on the filesystem exists.
@@ -371,6 +374,10 @@ public:
   /// bits are xxxx.yy.zz.  Largest number is 65535.255.255
   static bool parsePackedVersion(StringRef str, uint32_t &result);
 
+  /// Construct 64-bit value from string "A.B.C.D.E" where
+  /// bits are aaaa.bb.cc.dd.ee.  Largest number is 16777215.1023.1023.1023.1023
+  static bool parsePackedVersion(StringRef str, uint64_t &result);
+
   void finalizeInputFiles() override;
 
   std::error_code handleLoadedFile(File &file) override;
@@ -424,6 +431,7 @@ private:
   OS _os;
   uint32_t _osMinVersion;
   uint32_t _sdkVersion = 0;
+  uint64_t _sourceVersion = 0;
   uint64_t _pageZeroSize;
   uint64_t _pageSize;
   uint64_t _baseAddress;

lld/lib/Driver/DarwinLdDriver.cpp

@@ -812,6 +812,17 @@ bool DarwinLdDriver::parse(llvm::ArrayRef<const char *> args,
     ctx.setSdkVersion(ctx.osMinVersion());
   }
 
+  // Handle source_version
+  if (llvm::opt::Arg *arg = parsedArgs.getLastArg(OPT_source_version)) {
+    uint64_t version = 0;
+    if (MachOLinkingContext::parsePackedVersion(arg->getValue(),
+                                                version)) {
+      diagnostics << "error: malformed source_version value\n";
+      return false;
+    }
+    ctx.setSourceVersion(version);
+  }
+
   // Handle stack_size
   if (llvm::opt::Arg *stackSize = parsedArgs.getLastArg(OPT_stack_size)) {
     uint64_t stackSizeVal;

lld/lib/Driver/DarwinLdOptions.td

@@ -36,6 +36,9 @@ def ios_simulator_version_min : Separate<["-"], "ios_simulator_version_min">,
 def sdk_version : Separate<["-"], "sdk_version">,
      MetaVarName<"<version>">,
      HelpText<"SDK version">, Group<grp_opts>;
+def source_version : Separate<["-"], "source_version">,
+     MetaVarName<"<version>">,
+     HelpText<"Source version">, Group<grp_opts>;
 def version_load_command : Flag<["-"], "version_load_command">,
      HelpText<"Force generation of a version load command">, Group<grp_opts>;
 def no_version_load_command : Flag<["-"], "no_version_load_command">,

lld/lib/ReaderWriter/MachO/MachOLinkingContext.cpp

@@ -76,6 +76,35 @@ bool MachOLinkingContext::parsePackedVersion(StringRef str, uint32_t &result) {
   return false;
 }
 
+bool MachOLinkingContext::parsePackedVersion(StringRef str, uint64_t &result) {
+  result = 0;
+
+  if (str.empty())
+    return false;
+
+  SmallVector<StringRef, 5> parts;
+  llvm::SplitString(str, parts, ".");
+
+  uint64_t num;
+  if (llvm::getAsUnsignedInteger(parts[0], 10, num))
+    return true;
+  if (num > 0xFFFFFF)
+    return true;
+  result = num << 40;
+
+  unsigned Shift = 30;
+  for (StringRef str : llvm::makeArrayRef(parts).slice(1)) {
+    if (llvm::getAsUnsignedInteger(str, 10, num))
+      return true;
+    if (num > 0x3FF)
+      return true;
+    result |= (num << Shift);
+    Shift -= 10;
+  }
+
+  return false;
+}
+
 MachOLinkingContext::ArchInfo MachOLinkingContext::_s_archInfos[] = {
   { "x86_64", arch_x86_64, true,  CPU_TYPE_X86_64,  CPU_SUBTYPE_X86_64_ALL },
   { "i386",   arch_x86,    true,  CPU_TYPE_I386,    CPU_SUBTYPE_X86_ALL },

lld/lib/ReaderWriter/MachO/MachONormalizedFileBinaryWriter.cpp

@@ -467,6 +467,10 @@ uint32_t MachOFileLayout::loadCommandsSize(uint32_t &count) {
     ++count;
   }
 
+  // Add LC_SOURCE_VERSION
+  size += sizeof(source_version_command);
+  ++count;
+
   // If main executable add LC_MAIN
   if (_file.fileType == llvm::MachO::MH_EXECUTE) {
     size += sizeof(entry_point_command);
@@ -915,6 +919,17 @@ std::error_code MachOFileLayout::writeLoadCommands() {
     // LC_VERSION_MIN_TVOS
     writeVersionMinLoadCommand(_file, _swap, lc);
 
+    // Add LC_SOURCE_VERSION
+    {
+      source_version_command* sv = reinterpret_cast<source_version_command*>(lc);
+      sv->cmd       = LC_SOURCE_VERSION;
+      sv->cmdsize   = sizeof(source_version_command);
+      sv->version   = _file.sourceVersion;
+      if (_swap)
+        swapStruct(*sv);
+      lc += sizeof(source_version_command);
+    }
+
     // If main executable, add LC_MAIN.
     if (_file.fileType == llvm::MachO::MH_EXECUTE) {
       // Build LC_MAIN load command.

lld/lib/ReaderWriter/MachO/MachONormalizedFileFromAtoms.cpp

@@ -1285,6 +1285,7 @@ normalizedFromAtoms(const lld::File &atomFile,
   normFile.minOSVersionKind = util.minVersionCommandType();
 
   normFile.sdkVersion = context.sdkVersion();
+  normFile.sourceVersion = context.sourceVersion();
 
   if (context.generateVersionLoadCommand() &&
       context.os() != MachOLinkingContext::OS::unknown)