[lld/mac] fill in current and compatibility version for LC_LOAD_(WEAK_)DYLIB

Not sure if anything actually depends on this, but it makes `otool -L`
output look nicer.

Differential Revision: https://reviews.llvm.org/D93332

lld/MachO/InputFiles.cpp

@@ -537,6 +537,8 @@ DylibFile::DylibFile(MemoryBufferRef mb, DylibFile *umbrella)
   // Initialize dylibName.
   if (const load_command *cmd = findCommand(hdr, LC_ID_DYLIB)) {
     auto *c = reinterpret_cast<const dylib_command *>(cmd);
+    currentVersion = read32le(&c->dylib.current_version);
+    compatibilityVersion = read32le(&c->dylib.compatibility_version);
     dylibName = reinterpret_cast<const char *>(cmd) + read32le(&c->dylib.name);
   } else {
     error("dylib " + toString(this) + " missing LC_ID_DYLIB load command");
@@ -583,6 +585,8 @@ DylibFile::DylibFile(const InterfaceFile &interface, DylibFile *umbrella)
     umbrella = this;
 
   dylibName = saver.save(interface.getInstallName());
+  compatibilityVersion = interface.getCompatibilityVersion().rawValue();
+  currentVersion = interface.getCurrentVersion().rawValue();
   DylibFile *exportingFile = isImplicitlyLinked(dylibName) ? this : umbrella;
   auto addSymbol = [&](const Twine &name) -> void {
     symbols.push_back(symtab->addDylib(saver.save(name), exportingFile,

lld/MachO/InputFiles.h

@@ -132,6 +132,8 @@ public:
   static bool classof(const InputFile *f) { return f->kind() == DylibKind; }
 
   StringRef dylibName;
+  uint32_t compatibilityVersion = 0;
+  uint32_t currentVersion = 0;
   uint64_t ordinal = 0; // Ordinal numbering starts from 1, so 0 is a sentinel
   bool reexport = false;
   bool forceWeakImport = false;

lld/MachO/Writer.cpp

@@ -467,7 +467,9 @@ void Writer::createLoadCommands() {
       // loaded via LC_LOAD_WEAK_DYLIB.
       LoadCommandType lcType =
           dylibFile->forceWeakImport ? LC_LOAD_WEAK_DYLIB : LC_LOAD_DYLIB;
-      in.header->addLoadCommand(make<LCDylib>(lcType, dylibFile->dylibName));
+      in.header->addLoadCommand(make<LCDylib>(lcType, dylibFile->dylibName,
+                                              dylibFile->compatibilityVersion,
+                                              dylibFile->currentVersion));
       dylibFile->ordinal = dylibOrdinal++;
 
       if (dylibFile->reexport)

lld/test/MachO/dylink.s

@@ -4,8 +4,9 @@
 # RUN:   -o %t/libhello.o
 # RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %p/Inputs/libgoodbye.s \
 # RUN:   -o %t/libgoodbye.o
-# RUN: %lld -dylib -install_name \
-# RUN:   @executable_path/libhello.dylib %t/libhello.o -o %t/libhello.dylib
+# RUN: %lld -dylib -install_name @executable_path/libhello.dylib \
+# RUN:   -compatibility_version 10 -current_version 11 \
+# RUN:   %t/libhello.o -o %t/libhello.dylib
 # RUN: %lld -dylib -install_name \
 # RUN:   @executable_path/libgoodbye.dylib %t/libgoodbye.o -o %t/libgoodbye.dylib
 
@@ -51,12 +52,15 @@
 # RUN: llvm-objdump --macho --all-headers %t/dylink | FileCheck %s \
 # RUN:   --check-prefix=LOAD --implicit-check-not LC_LOAD_DYLIB
 
-# LOAD:              cmd LC_LOAD_DYLIB
-# LOAD-NEXT:     cmdsize
-# LOAD-NEXT:        name @executable_path/libhello.dylib
-# LOAD:              cmd LC_LOAD_DYLIB
-# LOAD-NEXT:     cmdsize
-# LOAD-NEXT:        name @executable_path/libgoodbye.dylib
+# LOAD:                        cmd LC_LOAD_DYLIB
+# LOAD-NEXT:               cmdsize
+# LOAD-NEXT:                  name @executable_path/libhello.dylib
+# LOAD-NEXT:            time stamp
+# LOAD-NEXT:       current version 11.0.0
+# LOAD-NEXT: compatibility version 10.0.0
+# LOAD:                        cmd LC_LOAD_DYLIB
+# LOAD-NEXT:               cmdsize
+# LOAD-NEXT:                  name @executable_path/libgoodbye.dylib
 
 .section __TEXT,__text
 .globl _main

lld/test/MachO/stub-link.s

@@ -18,6 +18,16 @@
 # CHECK-DAG: __DATA __data {{.*}} pointer 0 CoreFoundation _OBJC_EHTYPE_$_NSException
 # CHECK-DAG: __DATA __data {{.*}} pointer 0 libc++abi      ___gxx_personality_v0
 
+# RUN: llvm-objdump --macho --all-headers %t/test | \
+# RUN:     FileCheck --check-prefix=LOAD %s
+
+# LOAD:          cmd LC_LOAD_DYLIB
+# LOAD-NEXT:               cmdsize
+# LOAD-NEXT:                  name /usr/lib/libSystem.B.dylib
+# LOAD-NEXT:            time stamp
+# LOAD-NEXT:       current version 1.1.0
+# LOAD-NEXT: compatibility version
+
 .section __TEXT,__text
 .global _main