Header thinning feature now ships the appropriate Apple SDK with header scanner tool to ensure that the correct headers are detected without building any assumptions into the tool.

--
PiperOrigin-RevId: 150238621
MOS_MIGRATED_REVID=150238621

4 files changed, 55 insertions, 3 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/rules/objc/CompilationSupport.java b/src/main/java/com/google/devtools/build/lib/rules/objc/CompilationSupport.java
index adad227027..36fc313b11 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/objc/CompilationSupport.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/objc/CompilationSupport.java
@@ -1171,6 +1171,8 @@ public abstract class CompilationSupport {
     }
 
     FilesToRunProvider headerScannerTool = getHeaderThinningToolExecutable();
+    PrerequisiteArtifacts appleSdks =
+        ruleContext.getPrerequisiteArtifacts(ObjcRuleClasses.APPLE_SDK_ATTRIBUTE, Mode.TARGET);
     ListMultimap<ImmutableList<String>, ObjcHeaderThinningInfo>
         objcHeaderThinningInfoByCommandLine = groupActionsByCommandLine(headerThinningInfo);
     // Register a header scanning spawn action for each unique set of command line arguments
@@ -1178,8 +1180,22 @@ public abstract class CompilationSupport {
       SpawnAction.Builder builder =
           new SpawnAction.Builder()
               .setMnemonic("ObjcHeaderScanning")
-              .setExecutable(headerScannerTool);
-      CustomCommandLine.Builder cmdLine = CustomCommandLine.builder();
+              .setExecutable(headerScannerTool)
+              .addInputs(appleSdks.list());
+      CustomCommandLine.Builder cmdLine =
+          CustomCommandLine.builder()
+              .add("--arch")
+              .add(appleConfiguration.getSingleArchitecture().toLowerCase())
+              .add("--platform")
+              .add(appleConfiguration.getSingleArchPlatform().getLowerCaseNameInPlist())
+              .add("--sdk_version")
+              .add(
+                  appleConfiguration
+                      .getSdkVersionForPlatform(appleConfiguration.getSingleArchPlatform())
+                      .toStringWithMinimumComponents(2))
+              .add("--xcode_version")
+              .add(appleConfiguration.getXcodeVersion().toStringWithMinimumComponents(2))
+              .add("--");
       for (ObjcHeaderThinningInfo info : objcHeaderThinningInfoByCommandLine.get(args)) {
         cmdLine.addJoinPaths(
             ":",
diff --git a/src/main/java/com/google/devtools/build/lib/rules/objc/ObjcCommandLineOptions.java b/src/main/java/com/google/devtools/build/lib/rules/objc/ObjcCommandLineOptions.java
index 15a775a4c7..71266797eb 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/objc/ObjcCommandLineOptions.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/objc/ObjcCommandLineOptions.java
@@ -305,6 +305,17 @@ public class ObjcCommandLineOptions extends FragmentOptions {
   )
   public Label objcHeaderScannerTool;
 
+  @Option(
+    name = "apple_sdk",
+    defaultValue = "null",
+    category = "undocumented",
+    converter = LabelConverter.class,
+    help =
+        "Location of target that will provide the appropriate Apple SDK for the current build "
+            + "configuration."
+  )
+  public Label appleSdk;
+
   @Override
   public FragmentOptions getHost(boolean fallback) {
     ObjcCommandLineOptions host = (ObjcCommandLineOptions) super.getHost(fallback);
diff --git a/src/main/java/com/google/devtools/build/lib/rules/objc/ObjcConfiguration.java b/src/main/java/com/google/devtools/build/lib/rules/objc/ObjcConfiguration.java
index ec93b71ada..da9fd874b7 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/objc/ObjcConfiguration.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/objc/ObjcConfiguration.java
@@ -82,6 +82,7 @@ public class ObjcConfiguration extends BuildConfiguration.Fragment {
   private final HeaderDiscovery.DotdPruningMode dotdPruningPlan;
   private final boolean experimentalHeaderThinning;
   private final Label objcHeaderScannerTool;
+  private final Label appleSdk;
   private final boolean generateXcodeProject;
 
   ObjcConfiguration(ObjcCommandLineOptions objcOptions, BuildConfiguration.Options options,
@@ -123,6 +124,7 @@ public class ObjcConfiguration extends BuildConfiguration.Fragment {
             : HeaderDiscovery.DotdPruningMode.DO_NOT_USE;
     this.experimentalHeaderThinning = objcOptions.experimentalObjcHeaderThinning;
     this.objcHeaderScannerTool = objcOptions.objcHeaderScannerTool;
+    this.appleSdk = objcOptions.appleSdk;
     this.generateXcodeProject = objcOptions.generateXcodeProject;
   }
 
@@ -365,6 +367,11 @@ public class ObjcConfiguration extends BuildConfiguration.Fragment {
     return objcHeaderScannerTool;
   }
 
+  /** Returns the label for the Apple SDK for current build configuration. */
+  public Label getAppleSdk() {
+    return appleSdk;
+  }
+
   /**
    * Returns {@code true} if an xcodegen project should be added to a target's files to build.
    */
diff --git a/src/main/java/com/google/devtools/build/lib/rules/objc/ObjcRuleClasses.java b/src/main/java/com/google/devtools/build/lib/rules/objc/ObjcRuleClasses.java
index 80ea4c0a4d..887535b8ef 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/objc/ObjcRuleClasses.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/objc/ObjcRuleClasses.java
@@ -70,8 +70,10 @@ public class ObjcRuleClasses {
    * Name of the attribute used for implicit dependency on the libtool wrapper.
    */
   public static final String LIBTOOL_ATTRIBUTE = "$libtool";
-  /** Name of the attribute used for implicit dependency on the header_scanner wrapper. */
+  /** Name of the attribute used for implicit dependency on the header_scanner tool. */
   public static final String HEADER_SCANNER_ATTRIBUTE = ":header_scanner";
+  /** Name of attribute used for implicit dependency on the apple SDKs. */
+  public static final String APPLE_SDK_ATTRIBUTE = ":apple_sdk";
 
   static final String CLANG = "clang";
   static final String CLANG_PLUSPLUS = "clang++";
@@ -764,6 +766,22 @@ public class ObjcRuleClasses {
                               .getObjcHeaderScannerTool();
                         }
                       }))
+          .add(
+              attr(APPLE_SDK_ATTRIBUTE, LABEL)
+                  .value(
+                      new LateBoundLabel<BuildConfiguration>(ObjcConfiguration.class) {
+                        @Override
+                        public Label resolve(
+                            Rule rule, AttributeMap attributes, BuildConfiguration configuration) {
+                          ObjcConfiguration objcConfiguration =
+                              configuration.getFragment(ObjcConfiguration.class);
+                          // Apple SDKs are currently only used by ObjC header thinning feature
+                          if (objcConfiguration.useExperimentalHeaderThinning()) {
+                            return objcConfiguration.getAppleSdk();
+                          }
+                          return null;
+                        }
+                      }))
           .build();
     }
     @Override