[lld-macho] Simulator & DriverKit executables should always be PIE

[int3]

Summary

We didn't have support for parsing DriverKit in our -platform
flag, so add that too. Also remove a bunch of unnecessary namespace
prefixes.

[int3]

update

[int3]

fix test

[thakis]

(nit: Consider checking in obviously-behavior-preserving changes like stripping namespace prefixes without pre-commit review, and only send out the behavior-changing bits.)

[int3]

Thanks! Will do that in the future.

lld/MachO/Driver.cpp

 
 static void handlePlatformVersion(const opt::Arg *arg) {
   StringRef platformStr = arg->getValue(0);
   StringRef minVersionStr = arg->getValue(1);
   StringRef sdkVersionStr = arg->getValue(2);
 
   // TODO(compnerd) see if we can generate this case list via XMACROS
   config->platform.kind =
-      llvm::StringSwitch<llvm::MachO::PlatformKind>(lowerDash(platformStr))
-          .Cases("macos", "1", llvm::MachO::PlatformKind::macOS)
-          .Cases("ios", "2", llvm::MachO::PlatformKind::iOS)
-          .Cases("tvos", "3", llvm::MachO::PlatformKind::tvOS)
-          .Cases("watchos", "4", llvm::MachO::PlatformKind::watchOS)
-          .Cases("bridgeos", "5", llvm::MachO::PlatformKind::bridgeOS)
-          .Cases("mac-catalyst", "6", llvm::MachO::PlatformKind::macCatalyst)
-          .Cases("ios-simulator", "7", llvm::MachO::PlatformKind::iOSSimulator)
-          .Cases("tvos-simulator", "8",
-                 llvm::MachO::PlatformKind::tvOSSimulator)
-          .Cases("watchos-simulator", "9",
-                 llvm::MachO::PlatformKind::watchOSSimulator)
-          .Default(llvm::MachO::PlatformKind::unknown);
-  if (config->platform.kind == llvm::MachO::PlatformKind::unknown)
+      StringSwitch<PlatformKind>(lowerDash(platformStr))
+          .Cases("macos", "1", PlatformKind::macOS)
+          .Cases("ios", "2", PlatformKind::iOS)
+          .Cases("tvos", "3", PlatformKind::tvOS)
+          .Cases("watchos", "4", PlatformKind::watchOS)
+          .Cases("bridgeos", "5", PlatformKind::bridgeOS)
+          .Cases("mac-catalyst", "6", PlatformKind::macCatalyst)
+          .Cases("ios-simulator", "7", PlatformKind::iOSSimulator)
+          .Cases("tvos-simulator", "8", PlatformKind::tvOSSimulator)
+          .Cases("watchos-simulator", "9", PlatformKind::watchOSSimulator)
+          .Cases("driverkit", "10", PlatformKind::driverKit)
+          .Default(PlatformKind::unknown);
+  if (config->platform.kind == PlatformKind::unknown)
     error(Twine("malformed platform: ") + platformStr);
   // TODO: check validity of version strings, which varies by platform
   // NOTE: ld64 accepts version strings with 5 components
   // llvm::VersionTuple accepts no more than 4 components
   // Has Apple ever published version strings with 5 components?
   if (config->platform.minimum.tryParse(minVersionStr))
     error(Twine("malformed minimum version: ") + minVersionStr);
   if (config->platform.sdk.tryParse(sdkVersionStr))

 static bool isPie(opt::InputArgList &args) {
   if (config->outputType != MH_EXECUTE || args.hasArg(OPT_no_pie))
     return false;
 
   // TODO: add logic here as we support more archs. E.g. i386 should default
   // to PIE from 10.7, arm64 should always be PIE, etc
   assert(config->arch == AK_x86_64 || config->arch == AK_x86_64h);
 
-  if (config->platform.kind == MachO::PlatformKind::macOS &&
+  PlatformKind kind = config->platform.kind;
+  if (kind == PlatformKind::macOS &&
       config->platform.minimum >= VersionTuple(10, 6))
     return true;
 
+  if (kind == PlatformKind::iOSSimulator || kind == PlatformKind::driverKit)
+    return true;
+
   return args.hasArg(OPT_pie);
 }
 
 static void parseClangOption(StringRef opt, const Twine &msg) {
   std::string err;
   raw_string_ostream os(err);
 
   const char *argv[] = {"lld", opt.data()};

lld/test/MachO/x86-64-reloc-unsigned.s

 # REQUIRES: x86
 # RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %s -o %t.o
 # RUN: %lld -o %t %t.o
 # RUN: llvm-objdump --macho --rebase --full-contents %t | FileCheck %s
 
 # RUN: %lld -pie -o %t-pie %t.o
 # RUN: llvm-objdump --macho --rebase %t-pie | FileCheck %s --check-prefix=PIE
 # RUN: %lld -pie -no_pie -o %t-no-pie %t.o
 # RUN: llvm-objdump --macho --rebase %t-no-pie | FileCheck %s --check-prefix=NO-PIE
 # RUN: %lld -no_pie -pie -o %t-no-pie %t.o
 # RUN: llvm-objdump --macho --rebase %t-no-pie | FileCheck %s --check-prefix=NO-PIE
 
 # RUN: %lld -platform_version macos 10.6.0 11.0 -o %t-pie %t.o
 # RUN: llvm-objdump --macho --rebase %t-pie | FileCheck %s --check-prefix=PIE
 # RUN: %lld -platform_version macos 10.5.0 11.0 -o %t-no-pie %t.o
 # RUN: llvm-objdump --macho --rebase %t-no-pie | FileCheck %s --check-prefix=NO-PIE
+# RUN: %lld -platform_version ios-simulator 11.0.0 14.2 -o %t-pie %t.o
+# RUN: llvm-objdump --macho --rebase %t-pie | FileCheck %s --check-prefix=PIE
+# RUN: %lld -platform_version driverkit 19.0 20.0 -o %t-pie %t.o
+# RUN: llvm-objdump --macho --rebase %t-pie | FileCheck %s --check-prefix=PIE
 
 # CHECK:       Contents of section __DATA,foo:
 # CHECK-NEXT:  100001000 08100000 01000000
 # CHECK:       Contents of section __DATA,bar:
 # CHECK-NEXT:  100001008 011000f0 11211111 02000000
 # CHECK:       Rebase table:
 # CHECK-NEXT:  segment  section            address     type
 # CHECK-EMPTY: