[Driver] Always link compiler_rt on Darwin

Turns out it's needed for normal builtins that can appear in inlinable
functions, including Objective-C's @available. Clang always links it
unconditionally, so so should Swift.

Note that this does mean you have to build compiler_rt to get a
successful test run on Apple platforms. That was always true if you
wanted the sanitizer tests to work, though.

rdar://problem/41911599

Author: jrose-apple

lib/Driver/DarwinToolChains.cpp

@@ -84,22 +84,29 @@ toolchains::Darwin::constructInvocation(const InterpretJobAction &job,
 }
 
 static StringRef
-getDarwinLibraryNameSuffixForTriple(const llvm::Triple &triple) {
+getDarwinLibraryNameSuffixForTriple(const llvm::Triple &triple,
+                                    bool distinguishSimulator = true) {
   switch (getDarwinPlatformKind(triple)) {
   case DarwinPlatformKind::MacOS:
     return "osx";
+  case DarwinPlatformKind::IPhoneOSSimulator:
+    if (distinguishSimulator)
+      return "iossim";
+    LLVM_FALLTHROUGH;
   case DarwinPlatformKind::IPhoneOS:
     return "ios";
-  case DarwinPlatformKind::IPhoneOSSimulator:
-    return "iossim";
+  case DarwinPlatformKind::TvOSSimulator:
+    if (distinguishSimulator)
+      return "tvossim";
+    LLVM_FALLTHROUGH;
   case DarwinPlatformKind::TvOS:
     return "tvos";
-  case DarwinPlatformKind::TvOSSimulator:
-    return "tvossim";
+  case DarwinPlatformKind::WatchOSSimulator:
+    if (distinguishSimulator)
+      return "watchossim";
+    LLVM_FALLTHROUGH;
   case DarwinPlatformKind::WatchOS:
     return "watchos";
-  case DarwinPlatformKind::WatchOSSimulator:
-    return "watchossim";
   }
   llvm_unreachable("Unsupported Darwin platform");
 }
@@ -261,6 +268,13 @@ toolchains::Darwin::constructInvocation(const LinkJobAction &job,
 
   assert(Triple.isOSDarwin());
 
+  // Always link the regular compiler_rt.
+  addLinkRuntimeLib(context.Args, Arguments,
+                    (Twine("libclang_rt.") +
+                     getDarwinLibraryNameSuffixForTriple(Triple,
+                                                         /*simulator*/false) +
+                     ".a").str());
+
   // FIXME: If we used Clang as a linker instead of going straight to ld,
   // we wouldn't have to replicate Clang's logic here.
   bool wantsObjCRuntime = false;

test/Driver/linker.swift

@@ -77,6 +77,7 @@
 // CHECK: -o [[OBJECTFILE:.*]]
 
 // CHECK-NEXT: bin/ld{{"? }}
+// CHECK-DAG: lib/darwin/libclang_rt.osx.a
 // CHECK-DAG: [[OBJECTFILE]]
 // CHECK-DAG: -L [[STDLIB_PATH:[^ ]+/lib/swift/macosx]]
 // CHECK-DAG: -rpath [[STDLIB_PATH]]
@@ -87,7 +88,7 @@
 
 // SIMPLE: bin/ld{{"? }}
 // SIMPLE-NOT: -syslibroot
-// SIMPLE-DAG: -macosx_version_min 10.{{[0-9]+}}.{{[0-9]+}}
+// SIMPLE: -macosx_version_min 10.{{[0-9]+}}.{{[0-9]+}}
 // SIMPLE-NOT: -syslibroot
 // SIMPLE: -o linker
 
@@ -97,6 +98,7 @@
 
 // SIMPLE_STATIC-NEXT: bin/ld{{"? }}
 // SIMPLE_STATIC: [[OBJECTFILE]]
+// SIMPLE_STATIC: lib/darwin/libclang_rt.osx.a
 // SIMPLE_STATIC: -lobjc
 // SIMPLE_STATIC: -lSystem
 // SIMPLE_STATIC: -arch x86_64
@@ -118,6 +120,7 @@
 // IOS_SIMPLE-DAG: -lSystem
 // IOS_SIMPLE-DAG: -arch x86_64
 // IOS_SIMPLE-DAG: -ios_simulator_version_min 7.1.{{[0-9]+}}
+// IOS_SIMPLE-DAG: lib/darwin/libclang_rt.ios.a
 // IOS_SIMPLE: -o linker
 
 
@@ -130,6 +133,7 @@
 // tvOS_SIMPLE-DAG: -lSystem
 // tvOS_SIMPLE-DAG: -arch x86_64
 // tvOS_SIMPLE-DAG: -tvos_simulator_version_min 9.0.{{[0-9]+}}
+// tvOS_SIMPLE-DAG: lib/darwin/libclang_rt.tvos.a
 // tvOS_SIMPLE: -o linker
 
 
@@ -142,6 +146,7 @@
 // watchOS_SIMPLE-DAG: -lSystem
 // watchOS_SIMPLE-DAG: -arch i386
 // watchOS_SIMPLE-DAG: -watchos_simulator_version_min 2.0.{{[0-9]+}}
+// watchOS_SIMPLE-DAG: lib/darwin/libclang_rt.watchos.a
 // watchOS_SIMPLE: -o linker
 
 
@@ -312,11 +317,11 @@
 
 
 // FILELIST: bin/ld{{"? }}
-// FILELIST-NOT: .o
+// FILELIST-NOT: .o{{"? }}
 // FILELIST: -filelist {{"?[^-]}}
-// FILELIST-NOT: .o
-// FILELIST: /a.o
-// FILELIST-NOT: .o
+// FILELIST-NOT: .o{{"? }}
+// FILELIST: /a.o{{"? }}
+// FILELIST-NOT: .o{{"? }}
 // FILELIST: -o linker
 
 

validation-test/Driver/Inputs/clang_rt-helper.h

@@ -0,0 +1,9 @@
+#include <stdbool.h>
+
+static inline bool testNewOS() {
+  if (__builtin_available(macOS 10.12, *)) {
+    return true;
+  } else {
+    return false;
+  }
+}

validation-test/Driver/clang_rt.swift

@@ -0,0 +1,8 @@
+// RUN: %target-build-swift -emit-executable %s -import-objc-header %S/Inputs/clang_rt-helper.h -o %t
+
+// Just make sure we can build and link successfully.
+if testNewOS() {
+  print("new!")
+} else {
+  print("old...")
+}