diff --git a/src/main/java/com/google/devtools/build/lib/analysis/actions/FileWriteAction.java b/src/main/java/com/google/devtools/build/lib/analysis/actions/FileWriteAction.java
index c7aa4cb63..e084bc27c 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/actions/FileWriteAction.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/actions/FileWriteAction.java
@@ -28,6 +28,7 @@ import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
+import java.io.PrintWriter;
 import java.util.zip.GZIPInputStream;
 import java.util.zip.GZIPOutputStream;
 
@@ -73,6 +74,8 @@ public final class FileWriteAction extends AbstractFileWriteAction {
    */
   private final CharSequence fileContents;
 
+  private final Artifact output;
+
   /** Minimum length (in chars) for content to be eligible for compression. */
   private static final int COMPRESS_CHARS_THRESHOLD = 256;
 
@@ -90,6 +93,7 @@ public final class FileWriteAction extends AbstractFileWriteAction {
       fileContents = new CompressedString((String) fileContents);
     }
     this.fileContents = fileContents;
+    this.output = output;
   }
 
   /**
@@ -230,11 +234,32 @@ public final class FileWriteAction extends AbstractFileWriteAction {
    */
   @Override
   protected String computeKey() {
+    // System.err.println("src/main/java/com/google/devtools/build/lib/analysis/actions/FileWriteAction.java => output: " + output.getExecPath());
+    // ".ckd" Compute Key Debug
+    PrintWriter computeKeyDebugWriter = null;
+    String computeKeyDebugFile = output.getExecPath() + ".FileWriteAction.ckd";
+    try {
+      computeKeyDebugWriter = new PrintWriter(computeKeyDebugFile, "UTF-8");
+    } catch (java.io.FileNotFoundException ex) {
+      System.err.println("Unable to create " + computeKeyDebugFile);
+    } catch (java.io.UnsupportedEncodingException ex) {
+      System.err.println("Unsupported encoding");
+    }
+
     Fingerprint f = new Fingerprint();
     f.addString(GUID);
+    computeKeyDebugWriter.println("GUID: " + GUID);
+
     f.addString(String.valueOf(makeExecutable));
+    computeKeyDebugWriter.println("MAKEEXECUTABLE: " + String.valueOf(makeExecutable));
+
     f.addString(getFileContents());
-    return f.hexDigestAndReset();
+    computeKeyDebugWriter.println("FILECONTENTS: " + getFileContents());
+
+    String rv = f.hexDigestAndReset();
+    computeKeyDebugWriter.println("KEY: " + rv);
+    computeKeyDebugWriter.close();
+    return rv;
   }
 
   /**
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/actions/SpawnAction.java b/src/main/java/com/google/devtools/build/lib/analysis/actions/SpawnAction.java
index 580788160..26883eb92 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/actions/SpawnAction.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/actions/SpawnAction.java
@@ -60,6 +60,7 @@ import com.google.devtools.build.lib.util.ShellEscaper;
 import com.google.devtools.build.lib.vfs.PathFragment;
 import com.google.protobuf.GeneratedMessage.GeneratedExtension;
 import java.nio.charset.Charset;
+import java.io.PrintWriter;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.LinkedHashMap;
@@ -91,6 +92,9 @@ public class SpawnAction extends AbstractAction implements ExecutionInfoSpecifie
 
   private final CommandLine argv;
 
+  private final Iterable<Artifact> inputs;
+  private final Iterable<Artifact> outputs;
+
   private final boolean executeUnconditionally;
   private final boolean isShellCommand;
   private final String progressMessage;
@@ -197,6 +201,9 @@ public class SpawnAction extends AbstractAction implements ExecutionInfoSpecifie
     this.mnemonic = mnemonic;
     this.executeUnconditionally = executeUnconditionally;
     this.extraActionInfoSupplier = extraActionInfoSupplier;
+
+    this.inputs = inputs;
+    this.outputs = outputs;
   }
 
   @Override
@@ -312,23 +319,89 @@ public class SpawnAction extends AbstractAction implements ExecutionInfoSpecifie
 
   @Override
   protected String computeKey() {
+    boolean genruleSetup = String.valueOf(Iterables.get(inputs, 0).getExecPath()).contains("genrule/genrule-setup.sh");
+    boolean validGenrule = genruleSetup && (Iterables.size(inputs) > 1);
+
+    String genruleScript = null;
+    if (validGenrule) {
+      genruleScript = String.valueOf(Iterables.get(inputs, 1).getExecPath());
+    }
+
+    // ".ckd" Compute Key Debug
+    PrintWriter computeKeyDebugWriter = null;
+    if (validGenrule) {
+      String computeKeyDebugFile = genruleScript + ".SpawnAction.ckd";
+      try {
+        computeKeyDebugWriter = new PrintWriter(computeKeyDebugFile, "UTF-8");
+      } catch (java.io.FileNotFoundException ex) {
+        System.err.println("Unable to create " + computeKeyDebugFile);
+      } catch (java.io.UnsupportedEncodingException ex) {
+        System.err.println("Unsupported encoding");
+      }
+    }
+
+    validGenrule = validGenrule && (computeKeyDebugWriter != null);
+
     Fingerprint f = new Fingerprint();
     f.addString(GUID);
+    if (validGenrule) { computeKeyDebugWriter.println("GUID: " + GUID); }
+
     f.addStrings(argv.arguments());
+    if (validGenrule) {
+      for (String input : argv.arguments()) {
+        computeKeyDebugWriter.println("ARGUMENTS: " + input);
+      }
+    }
+
     f.addString(getMnemonic());
+    if (validGenrule) { computeKeyDebugWriter.println("MNEMONIC: " + getMnemonic()); }
+
     // We don't need the toolManifests here, because they are a subset of the inputManifests by
     // definition and the output of an action shouldn't change whether something is considered a
     // tool or not.
     f.addPaths(getRunfilesSupplier().getRunfilesDirs());
+    if (validGenrule) {
+      for (PathFragment path : getRunfilesSupplier().getRunfilesDirs()) {
+        computeKeyDebugWriter.println("RUNFILESDIRS: " + path.getPathString());
+      }
+    }
+
     ImmutableList<Artifact> runfilesManifests = getRunfilesSupplier().getManifests();
     f.addInt(runfilesManifests.size());
+    if (validGenrule) { computeKeyDebugWriter.println("RUNFILESMANIFESTSSIZE: " + runfilesManifests.size()); }
+
     for (Artifact runfilesManifest : runfilesManifests) {
       f.addPath(runfilesManifest.getExecPath());
+      if (validGenrule) { computeKeyDebugWriter.println("RUNFILESMANIFEST: " + runfilesManifest.getExecPath().getPathString()); }
     }
+
     f.addStringMap(getEnvironment());
+    if (validGenrule) {
+      for (Map.Entry<String, String> entry : getEnvironment().entrySet()) {
+        computeKeyDebugWriter.println("ENV: " + entry.getKey() + "=" + entry.getValue());
+      }
+    }
+
     f.addStrings(getClientEnvironmentVariables());
+    if (validGenrule) {
+      for (String input : argv.arguments()) {
+        computeKeyDebugWriter.println("CLIENTENV: " + input);
+      }
+    }
+
     f.addStringMap(getExecutionInfo());
-    return f.hexDigestAndReset();
+    if (validGenrule) {
+      for (Map.Entry<String, String> entry : executionInfo.entrySet()) {
+        computeKeyDebugWriter.println("EXECINFO: " + entry.getKey() + "=" + entry.getValue());
+      }
+    }
+
+    String rv = f.hexDigestAndReset();
+    if (validGenrule) {
+      computeKeyDebugWriter.println("KEY: " + rv);
+      computeKeyDebugWriter.close();
+    }
+    return rv;
   }
 
   @Override
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppCompileAction.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppCompileAction.java
index 3559fffde..3ba39617c 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppCompileAction.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppCompileAction.java
@@ -1111,10 +1111,30 @@ public class CppCompileAction extends AbstractAction
 
   @Override
   public String computeKey() {
+    // ".ckd" Compute Key Debug
+    PrintWriter computeKeyDebugWriter = null;
+    String computeKeyDebugFile = getInternalOutputFile() + ".CppCompileAction.ckd";
+    try {
+      computeKeyDebugWriter = new PrintWriter(computeKeyDebugFile, "UTF-8");
+    } catch (java.io.FileNotFoundException ex) {
+      System.err.println("Unable to create " + computeKeyDebugFile);
+    } catch (java.io.UnsupportedEncodingException ex) {
+      System.err.println("Unsupported encoding");
+    }
+
     Fingerprint f = new Fingerprint();
     f.addUUID(actionClassId);
+    computeKeyDebugWriter.println("UUID: " + actionClassId);
+
     f.addStringMap(getEnvironment());
+    for (Map.Entry<String, String> entry : getEnvironment().entrySet()) {
+      computeKeyDebugWriter.println("ENV: " + entry.getKey() + "=" + entry.getValue());
+    }
+
     f.addStringMap(executionInfo);
+    for (Map.Entry<String, String> entry : executionInfo.entrySet()) {
+      computeKeyDebugWriter.println("EXECINFO: " + entry.getKey() + "=" + entry.getValue());
+    }
 
     // For the argv part of the cache key, ignore all compiler flags that explicitly denote module
     // file (.pcm) inputs. Depending on input discovery, some of the unused ones are removed from
@@ -1124,6 +1144,9 @@ public class CppCompileAction extends AbstractAction
     // A better long-term solution would be to make the compiler to find them automatically and
     // never hand in the .pcm files explicitly on the command line in the first place.
     f.addStrings(compileCommandLine.getArgv(getInternalOutputFile(), null));
+    for (String input : compileCommandLine.getArgv(getInternalOutputFile(), null)) {
+      computeKeyDebugWriter.println("COMMAND: " + input);
+    }
 
     /*
      * getArgv() above captures all changes which affect the compilation
@@ -1133,19 +1156,31 @@ public class CppCompileAction extends AbstractAction
      * have changed, otherwise we might miss some errors.
      */
     f.addPaths(context.getDeclaredIncludeDirs());
+    for (PathFragment path : context.getDeclaredIncludeDirs()) {
+      computeKeyDebugWriter.println("DECLAREDINCLUDEDIRS: " + path.getPathString());
+    }
     f.addPaths(context.getDeclaredIncludeWarnDirs());
+    for (PathFragment path : context.getDeclaredIncludeWarnDirs()) {
+      computeKeyDebugWriter.println("DECLAREDINCLUDEWARNDIRS: " + path.getPathString());
+    }
     for (Artifact declaredIncludeSrc : context.getDeclaredIncludeSrcs()) {
       f.addPath(declaredIncludeSrc.getExecPath());
+      computeKeyDebugWriter.println("DECLAREDINCLUDESRCS: " + declaredIncludeSrc.getExecPath().getPathString());
     }
     f.addInt(0);  // mark the boundary between input types
     for (Artifact input : getMandatoryInputs()) {
       f.addPath(input.getExecPath());
+      computeKeyDebugWriter.println("MANDATORYINPUTS: " + input.getExecPath().getPathString());
     }
     f.addInt(0);
     for (Artifact input : prunableInputs) {
       f.addPath(input.getExecPath());
+      computeKeyDebugWriter.println("PRUNABLEINPUTS: " + input.getExecPath().getPathString());
     }
-    return f.hexDigestAndReset();
+    String rv = f.hexDigestAndReset();
+    computeKeyDebugWriter.println("KEY: " + rv);
+    computeKeyDebugWriter.close();
+    return rv;
   }
 
   @Override