Add Bitcode symbol maps and AppleDebugOutputsProvider

* Bitcode symbol maps allow Apple to provide a new dSYM output when they recompile bitcode on the App Store. This makes it possible to debug apps build with embedded bitcode.

* The new debug outputs provider makes it easy (and correct) for other rules to post-process (package, analyze, upload) dSYM and Bitcode artifacts.

--
PiperOrigin-RevId: 145720293
MOS_MIGRATED_REVID=145720293

4 files changed, 163 insertions, 8 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/rules/objc/AppleBinary.java b/src/main/java/com/google/devtools/build/lib/rules/objc/AppleBinary.java
index 298b31493d..6fd9b70e7a 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/objc/AppleBinary.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/objc/AppleBinary.java
@@ -34,10 +34,12 @@ import com.google.devtools.build.lib.analysis.TransitiveInfoCollection;
 import com.google.devtools.build.lib.analysis.config.BuildConfiguration;
 import com.google.devtools.build.lib.collect.nestedset.NestedSetBuilder;
 import com.google.devtools.build.lib.rules.RuleConfiguredTargetFactory;
+import com.google.devtools.build.lib.rules.apple.AppleCommandLineOptions.AppleBitcodeMode;
 import com.google.devtools.build.lib.rules.apple.AppleConfiguration;
 import com.google.devtools.build.lib.rules.apple.Platform;
 import com.google.devtools.build.lib.rules.apple.Platform.PlatformType;
 import com.google.devtools.build.lib.rules.cpp.CcToolchainProvider;
+import com.google.devtools.build.lib.rules.objc.AppleDebugOutputsProvider.OutputType;
 import com.google.devtools.build.lib.rules.objc.CompilationSupport.ExtraLinkArgs;
 import java.util.Map;
 import java.util.Set;
@@ -156,6 +158,23 @@ public class AppleBinary implements RuleConfiguredTargetFactory {
       targetBuilder.addProvider(
           AppleExecutableBinaryProvider.class, new AppleExecutableBinaryProvider(outputArtifact));
     }
+
+    AppleDebugOutputsProvider.Builder builder = AppleDebugOutputsProvider.Builder.create();
+
+    if (appleConfiguration.getBitcodeMode() == AppleBitcodeMode.EMBEDDED) {
+      for (BuildConfiguration c : childConfigurations) {
+        String arch = c.getFragment(AppleConfiguration.class).getSingleArchitecture();
+        IntermediateArtifacts intermediateArtifacts =
+            new IntermediateArtifacts(
+                ruleContext, /*archiveFileNameSuffix*/ "", /*outputPrefix*/ "", c);
+        Artifact bitcodeSymbol = intermediateArtifacts.bitcodeSymbolMap();
+
+        builder.addOutput(arch, OutputType.BITCODE_SYMBOLS, bitcodeSymbol);
+      }
+    }
+
+    targetBuilder.addProvider(AppleDebugOutputsProvider.class, builder.build());
+
     return targetBuilder.build();
   }
 
diff --git a/src/main/java/com/google/devtools/build/lib/rules/objc/AppleDebugOutputsProvider.java b/src/main/java/com/google/devtools/build/lib/rules/objc/AppleDebugOutputsProvider.java
new file mode 100644
index 0000000000..d80c3238c4
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/rules/objc/AppleDebugOutputsProvider.java
@@ -0,0 +1,117 @@
+// Copyright 2017 The Bazel Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+package com.google.devtools.build.lib.rules.objc;
+
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.Maps;
+import com.google.devtools.build.lib.actions.Artifact;
+import com.google.devtools.build.lib.analysis.TransitiveInfoProvider;
+import com.google.devtools.build.lib.concurrent.ThreadSafety.Immutable;
+import com.google.devtools.build.lib.packages.SkylarkClassObject;
+import com.google.devtools.build.lib.packages.SkylarkClassObjectConstructor;
+import java.util.HashMap;
+import java.util.Map.Entry;
+
+/**
+ * A provider that holds debug outputs of an Apple binary rule.
+ *
+ * <p>This provider has no native interface and is intended to be read in Skylark code.
+ *
+ * <p>The only field it has is {@code output_map}, which is a dictionary of: { arch: { output_type:
+ * Artifact, output_type: Artifact, ... } }
+ *
+ * <p>Where {@code arch} is any Apple architecture such as "arm64" or "armv7", {@code output_type}
+ * is currently "bitcode_symbols", and the artifact is an instance of the {@link
+ * Artifact} class.
+ *
+ * <p>Example: { "arm64": { "bitcode_symbols": Artifact } }
+ */
+@Immutable
+public final class AppleDebugOutputsProvider extends SkylarkClassObject
+    implements TransitiveInfoProvider {
+
+  /** Expected types of debug outputs. */
+  enum OutputType {
+
+    // TODO(b/33839914): Add DWARF binaries for dSYM outputs.
+
+    /** A Bitcode symbol map, per architecture. */
+    BITCODE_SYMBOLS;
+
+    @Override
+    public String toString() {
+      return name().toLowerCase();
+    }
+  }
+
+  public static final SkylarkClassObjectConstructor SKYLARK_PROVIDER =
+      SkylarkClassObjectConstructor.createNative("AppleDebugOutputs");
+
+  /**
+   * Creates a new provider instance.
+   *
+   * @param map a map of
+   *     <pre>{@code
+   * {
+   *   arch: { output_type: Artifact, output_type: Artifact, ... },
+   * }
+   * }</pre>
+   *     Where:
+   *     <ul>
+   *       <li>arch - {@link String}, any Apple supported architecture (e.g. arm64, x86_64)
+   *       <li>output_type - an instance of {@link OutputType}
+   *     </ul>
+   */
+  private AppleDebugOutputsProvider(ImmutableMap<String, ImmutableMap<String, Artifact>> map) {
+    super(SKYLARK_PROVIDER, ImmutableMap.<String, Object>of("outputs_map", map));
+  }
+
+  /** A builder for {@link AppleDebugOutputsProvider}. */
+  public static class Builder {
+    private final HashMap<String, HashMap<String, Artifact>> outputsByArch = Maps.newHashMap();
+
+    private Builder() {}
+
+    public static Builder create() {
+      return new Builder();
+    }
+
+    /**
+     * Adds an output to the provider.
+     *
+     * @param arch any Apple architecture string, e.g. arm64, armv7.
+     * @param outputType {@link OutputType} corresponding to the artifact.
+     * @param artifact an {@link Artifact} that contains debug information.
+     * @return this builder.
+     */
+    public Builder addOutput(String arch, OutputType outputType, Artifact artifact) {
+      if (!outputsByArch.containsKey(arch)) {
+        outputsByArch.put(arch, new HashMap<String, Artifact>());
+      }
+
+      outputsByArch.get(arch).put(outputType.toString(), artifact);
+      return this;
+    }
+
+    public AppleDebugOutputsProvider build() {
+      ImmutableMap.Builder<String, ImmutableMap<String, Artifact>> builder = ImmutableMap.builder();
+
+      for (Entry<String, HashMap<String, Artifact>> e : outputsByArch.entrySet()) {
+        builder.put(e.getKey(), ImmutableMap.copyOf(e.getValue()));
+      }
+
+      return new AppleDebugOutputsProvider(builder.build());
+    }
+  }
+}
diff --git a/src/main/java/com/google/devtools/build/lib/rules/objc/IntermediateArtifacts.java b/src/main/java/com/google/devtools/build/lib/rules/objc/IntermediateArtifacts.java
index 2f588e7c6c..db3c1ad425 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/objc/IntermediateArtifacts.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/objc/IntermediateArtifacts.java
@@ -372,9 +372,12 @@ public final class IntermediateArtifacts {
             suffix));
   }
 
-  /**
-   * Representation for a specific architecture.
-   */
+  /** Bitcode symbol map generated for a linked binary, for a specific architecture. */
+  public Artifact bitcodeSymbolMap() {
+    return appendExtension(".bcsymbolmap");
+  }
+
+  /** Representation for a specific architecture. */
   private Artifact architectureRepresentation(String arch, String suffix) {
     return appendExtension(String.format("_%s%s", arch, suffix));
   }
diff --git a/src/main/java/com/google/devtools/build/lib/rules/objc/LegacyCompilationSupport.java b/src/main/java/com/google/devtools/build/lib/rules/objc/LegacyCompilationSupport.java
index f9b541ee73..3dfdd5f4c8 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/objc/LegacyCompilationSupport.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/objc/LegacyCompilationSupport.java
@@ -515,6 +515,7 @@ public class LegacyCompilationSupport extends CompilationSupport {
       DsymOutputType dsymOutputType) {
     Optional<Artifact> dsymBundleZip;
     Optional<Artifact> linkmap;
+    Optional<Artifact> bitcodeSymbolMap;
     if (objcConfiguration.generateDsym()) {
       registerDsymActions(dsymOutputType);
       dsymBundleZip = Optional.of(intermediateArtifacts.tempDsymBundleZip(dsymOutputType));
@@ -532,13 +533,20 @@ public class LegacyCompilationSupport extends CompilationSupport {
       linkmap = Optional.absent();
     }
 
+    if (appleConfiguration.getBitcodeMode() == AppleBitcodeMode.EMBEDDED) {
+      bitcodeSymbolMap = Optional.of(intermediateArtifacts.bitcodeSymbolMap());
+    } else {
+      bitcodeSymbolMap = Optional.absent();
+    }
+
     registerLinkAction(
         objcProvider,
         extraLinkArgs,
         extraLinkInputs,
         dsymBundleZip,
         prunedJ2ObjcArchives,
-        linkmap);
+        linkmap,
+        bitcodeSymbolMap);
     return this;
   }
 
@@ -552,7 +560,8 @@ public class LegacyCompilationSupport extends CompilationSupport {
       Iterable<Artifact> extraLinkInputs,
       Optional<Artifact> dsymBundleZip,
       Iterable<Artifact> prunedJ2ObjcArchives,
-      Optional<Artifact> linkmap) {
+      Optional<Artifact> linkmap,
+      Optional<Artifact> bitcodeSymbolMap) {
     Artifact binaryToLink = getBinaryToLink();
 
     ImmutableList<Artifact> objcLibraries = objcProvider.getObjcLibraries();
@@ -567,7 +576,8 @@ public class LegacyCompilationSupport extends CompilationSupport {
             dsymBundleZip,
             ccLibraries,
             bazelBuiltLibraries,
-            linkmap);
+            linkmap,
+            bitcodeSymbolMap);
     ruleContext.registerAction(
         ObjcRuleClasses.spawnAppleEnvActionBuilder(
                 appleConfiguration, appleConfiguration.getSingleArchPlatform())
@@ -577,6 +587,7 @@ public class LegacyCompilationSupport extends CompilationSupport {
             .addOutput(binaryToLink)
             .addOutputs(dsymBundleZip.asSet())
             .addOutputs(linkmap.asSet())
+            .addOutputs(bitcodeSymbolMap.asSet())
             .addInputs(bazelBuiltLibraries)
             .addTransitiveInputs(objcProvider.get(IMPORTED_LIBRARY))
             .addTransitiveInputs(objcProvider.get(STATIC_FRAMEWORK_FILE))
@@ -633,7 +644,8 @@ public class LegacyCompilationSupport extends CompilationSupport {
       Optional<Artifact> dsymBundleZip,
       Iterable<Artifact> ccLibraries,
       Iterable<Artifact> bazelBuiltLibraries,
-      Optional<Artifact> linkmap) {
+      Optional<Artifact> linkmap,
+      Optional<Artifact> bitcodeSymbolMap) {
     Iterable<String> libraryNames = libraryNames(objcProvider);
 
     CustomCommandLine.Builder commandLine = CustomCommandLine.builder()
@@ -680,7 +692,11 @@ public class LegacyCompilationSupport extends CompilationSupport {
     if (bitcodeMode == AppleBitcodeMode.EMBEDDED) {
       commandLine.add("-Xlinker").add("-bitcode_verify");
       commandLine.add("-Xlinker").add("-bitcode_hide_symbols");
-      // TODO(b/32910627): Add Bitcode symbol maps outputs.
+      commandLine
+          .add("-Xlinker")
+          .add("-bitcode_symbol_map")
+          .add("-Xlinker")
+          .add(bitcodeSymbolMap.get().getExecPathString());
     }
 
     commandLine