[Driver] Make sure the deployment target is earlier than iOS 11 when
it is inferred from -isysroot.

This fixes a change that was inadvertently introduced in r309607.

rdar://problem/32230613

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@309633 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit d00f966d136fcf99c3a38f4b17ae8bc97c75f543)

Conflicts:
lib/Driver/ToolChains/Darwin.cpp
diff --git a/lib/Driver/ToolChains.cpp b/lib/Driver/ToolChains.cpp
index b5ed905..a11c817 100644
--- a/lib/Driver/ToolChains.cpp
+++ b/lib/Driver/ToolChains.cpp
@@ -596,13 +596,12 @@
   unsigned Major, Minor, Micro;
   bool HadExtra;
 
-  // iOS 10 is the maximum deployment target for 32-bit targets.
-  if (iOSVersion && getTriple().isArch32Bit() &&
-      Driver::GetReleaseVersion(iOSVersion->getValue(), Major, Minor, Micro,
-                                HadExtra) &&
-      Major > 10)
-    getDriver().Diag(diag::warn_invalid_ios_deployment_target)
-        << iOSVersion->getAsString(Args);
+  // The iOS deployment target that is explicitly specified via a command line
+  // option or an environment variable.
+  std::string ExplicitIOSDeploymentTargetStr;
+
+  if (iOSVersion)
+    ExplicitIOSDeploymentTargetStr = iOSVersion->getAsString(Args);
 
   // Add a macro to differentiate between m(iphone|tv|watch)os-version-min=X.Y and
   // -m(iphone|tv|watch)simulator-version-min=X.Y.
@@ -645,13 +644,9 @@
     if (char *env = ::getenv("WATCHOS_DEPLOYMENT_TARGET"))
       WatchOSTarget = env;
 
-    // iOS 10 is the maximum deployment target for 32-bit targets.
-    if (!iOSTarget.empty() && getTriple().isArch32Bit() &&
-        Driver::GetReleaseVersion(iOSTarget.c_str(), Major, Minor, Micro,
-                                  HadExtra) &&
-        Major > 10)
-      getDriver().Diag(diag::warn_invalid_ios_deployment_target)
-          << std::string("IPHONEOS_DEPLOYMENT_TARGET=") + iOSTarget;
+    if (!iOSTarget.empty())
+      ExplicitIOSDeploymentTargetStr =
+          std::string("IPHONEOS_DEPLOYMENT_TARGET=") + iOSTarget;
 
     // If there is no command-line argument to specify the Target version and
     // no environment variable defined, see if we can set the default based
@@ -785,12 +780,19 @@
         HadExtra || Major >= 100 || Minor >= 100 || Micro >= 100)
       getDriver().Diag(diag::err_drv_invalid_version_number)
           << iOSVersion->getAsString(Args);
-    // iOS 10 is the maximum deployment target for 32-bit targets. If the
-    // inferred deployment target is iOS 11 or later, set it to 10.99.
+    // For 32-bit targets, the deployment target for iOS has to be earlier than
+    // iOS 11.
     if (getTriple().isArch32Bit() && Major >= 11) {
-      Major = 10;
-      Minor = 99;
-      Micro = 99;
+      // If the deployment target is explicitly specified, print a diagnostic.
+      if (!ExplicitIOSDeploymentTargetStr.empty()) {
+        getDriver().Diag(diag::warn_invalid_ios_deployment_target)
+            << ExplicitIOSDeploymentTargetStr;
+      // Otherwise, set it to 10.99.99.
+      } else {
+        Major = 10;
+        Minor = 99;
+        Micro = 99;
+      }
     }
   } else if (Platform == TvOS) {
     if (!Driver::GetReleaseVersion(TvOSVersion->getValue(), Major, Minor,
diff --git a/test/Driver/darwin-version.c b/test/Driver/darwin-version.c
index 7629270..a3e5fd8 100644
--- a/test/Driver/darwin-version.c
+++ b/test/Driver/darwin-version.c
@@ -26,6 +26,8 @@
 
 // RUN: %clang -target armv7-apple-ios11.1 -c -### %s 2>&1 | \
 // RUN: FileCheck --check-prefix=CHECK-VERSION-IOS7 %s
+// RUN: %clang -arch armv7 -isysroot SDKs/iPhoneOS11.0.sdk -c -### %s 2>&1 | \
+// RUN: FileCheck --check-prefix=CHECK-VERSION-IOS7 %s
 // CHECK-VERSION-IOS7: thumbv7-apple-ios10.99.99
 
 // RUN: env IPHONEOS_DEPLOYMENT_TARGET=11.0 \