Automated g4 rollback of commit cbbb423663b154d82e3dfa5e9a56839583987999.

*** Reason for rollback ***

Need to roll this back as part of http://b/38171368

*** Original change description ***

RELNOTES: Effectively remove sysroot from CppConfiguration and allow it to use select statements.
PiperOrigin-RevId: 155547813

13 files changed, 251 insertions, 229 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CcBinary.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CcBinary.java
index 7e15d9e462..ca98d7bf61 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CcBinary.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CcBinary.java
@@ -523,7 +523,8 @@ public abstract class CcBinary implements RuleConfiguredTargetFactory {
 
   private static final boolean dashStaticInLinkopts(List<String> linkopts,
       CppConfiguration cppConfiguration) {
-    return linkopts.contains("-static") || cppConfiguration.hasStaticLinkOption();
+    return linkopts.contains("-static")
+        || cppConfiguration.getLinkOptions().contains("-static");
   }
 
   private static final LinkStaticness getLinkStaticness(RuleContext context,
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CcToolchain.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CcToolchain.java
index da27ada49e..6fc4c92938 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CcToolchain.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CcToolchain.java
@@ -36,7 +36,6 @@ import com.google.devtools.build.lib.analysis.TransitiveInfoCollection;
 import com.google.devtools.build.lib.analysis.actions.SpawnAction;
 import com.google.devtools.build.lib.analysis.actions.SymlinkAction;
 import com.google.devtools.build.lib.analysis.config.CompilationMode;
-import com.google.devtools.build.lib.analysis.config.InvalidConfigurationException;
 import com.google.devtools.build.lib.cmdline.Label;
 import com.google.devtools.build.lib.collect.nestedset.NestedSet;
 import com.google.devtools.build.lib.collect.nestedset.NestedSetBuilder;
@@ -285,15 +284,6 @@ public class CcToolchain implements RuleConfiguredTargetFactory {
       coverage = crosstool;
     }
 
-    PathFragment sysroot = calculateSysroot(ruleContext);
-
-    ImmutableList<PathFragment> builtInIncludeDirectories = null;
-    try {
-      builtInIncludeDirectories = cppConfiguration.getBuiltInIncludeDirectories(sysroot);
-    } catch (InvalidConfigurationException e) {
-      ruleContext.ruleError(e.getMessage());
-    }
-
     CcToolchainProvider ccProvider =
         new CcToolchainProvider(
             cppConfiguration,
@@ -320,8 +310,9 @@ public class CcToolchain implements RuleConfiguredTargetFactory {
             coverageEnvironment.build(),
             ruleContext.getPrerequisiteArtifact("$link_dynamic_library_tool", Mode.HOST),
             getEnvironment(ruleContext),
-            builtInIncludeDirectories,
-            sysroot);
+            cppConfiguration.getBuiltInIncludeDirectories());
+
+    PathFragment sysroot = cppConfiguration.getSysroot();
 
     MakeVariableProvider makeVariableProvider =
         createMakeVariableProvider(cppConfiguration, sysroot);
@@ -490,16 +481,4 @@ public class CcToolchain implements RuleConfiguredTargetFactory {
   protected ImmutableMap<String, String> getEnvironment(RuleContext ruleContext) {
     return ImmutableMap.<String, String>of();
   }
-
-  private PathFragment calculateSysroot(RuleContext ruleContext) {
-
-    TransitiveInfoCollection sysrootTarget = ruleContext.getPrerequisite(":sysroot", Mode.TARGET);
-    if (sysrootTarget == null) {
-      CppConfiguration cppConfiguration =
-          Preconditions.checkNotNull(ruleContext.getFragment(CppConfiguration.class));
-      return cppConfiguration.getDefaultSysroot();
-    }
-
-    return sysrootTarget.getLabel().getPackageFragment();
-  }
 }
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CcToolchainProvider.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CcToolchainProvider.java
index 89beafe21d..26d4c38b67 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CcToolchainProvider.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CcToolchainProvider.java
@@ -75,8 +75,7 @@ public final class CcToolchainProvider
           NestedSetBuilder.<Pair<String, String>>emptySet(Order.COMPILE_ORDER),
           null,
           ImmutableMap.<String, String>of(),
-          ImmutableList.<PathFragment>of(),
-          null);
+          ImmutableList.<PathFragment>of());
 
   @Nullable private final CppConfiguration cppConfiguration;
   private final NestedSet<Artifact> crosstool;
@@ -103,7 +102,6 @@ public final class CcToolchainProvider
   @Nullable private final Artifact linkDynamicLibraryTool;
   private final ImmutableMap<String, String> environment;
   private final ImmutableList<PathFragment> builtInIncludeDirectories;
-  @Nullable private final PathFragment sysroot;
 
   public CcToolchainProvider(
       @Nullable CppConfiguration cppConfiguration,
@@ -130,8 +128,7 @@ public final class CcToolchainProvider
       NestedSet<Pair<String, String>> coverageEnvironment,
       Artifact linkDynamicLibraryTool,
       ImmutableMap<String, String> environment,
-      ImmutableList<PathFragment> builtInIncludeDirectories,
-      @Nullable PathFragment sysroot) {
+      ImmutableList<PathFragment> builtInIncludeDirectories) {
     super(SKYLARK_CONSTRUCTOR, ImmutableMap.<String, Object>of());
     this.cppConfiguration = cppConfiguration;
     this.crosstool = Preconditions.checkNotNull(crosstool);
@@ -158,7 +155,6 @@ public final class CcToolchainProvider
     this.linkDynamicLibraryTool = linkDynamicLibraryTool;
     this.environment = environment;
     this.builtInIncludeDirectories = builtInIncludeDirectories;
-    this.sysroot = sysroot;
   }
 
   @SkylarkCallable(
@@ -356,7 +352,7 @@ public final class CcToolchainProvider
             + "this method returns <code>None</code>."
   )
   public PathFragment getSysroot() {
-    return sysroot;
+    return cppConfiguration.getSysroot();
   }
 
   @SkylarkCallable(
@@ -366,7 +362,7 @@ public final class CcToolchainProvider
             + "rules. These should be appended to the command line after filtering."
   )
   public ImmutableList<String> getUnfilteredCompilerOptions(Iterable<String> features) {
-    return cppConfiguration.getUnfilteredCompilerOptions(features, sysroot);
+    return cppConfiguration.getUnfilteredCompilerOptions(features);
   }
 
   @SkylarkCallable(
@@ -377,6 +373,6 @@ public final class CcToolchainProvider
             + "inferred from the command-line options."
   )
   public ImmutableList<String> getLinkOptions() {
-    return cppConfiguration.getLinkOptions(sysroot);
+    return cppConfiguration.getLinkOptions();
   }
 }
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CcToolchainRule.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CcToolchainRule.java
index 8b7dbe92ff..a1922b8553 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CcToolchainRule.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CcToolchainRule.java
@@ -51,8 +51,9 @@ public final class CcToolchainRule implements RuleDefinition {
   private static final LateBoundLabel<BuildConfiguration> LIBC_TOP =
       new LateBoundLabel<BuildConfiguration>(CppConfiguration.class) {
         @Override
-        public Label resolve(Rule rule, AttributeMap attributes, BuildConfiguration configuration) {
-          return configuration.getFragment(CppConfiguration.class).getSysrootLabel();
+        public Label resolve(
+            Rule rule, AttributeMap attributes, BuildConfiguration configuration) {
+          return configuration.getFragment(CppConfiguration.class).getLibcLabel();
         }
       };
 
@@ -87,7 +88,6 @@ public final class CcToolchainRule implements RuleDefinition {
                 .value(env.getToolsLabel("//tools/cpp:link_dynamic_library")))
         // TODO(bazel-team): Should be using the TARGET configuration.
         .add(attr(":libc_top", LABEL).cfg(HOST).value(LIBC_TOP))
-        .add(attr(":sysroot", LABEL).value(LIBC_TOP))
         .add(
             attr(":lipo_context_collector", LABEL)
                 .cfg(LipoTransition.LIPO_COLLECTOR)
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CompileCommandLine.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CompileCommandLine.java
index 4310cef570..f9fc4c3f6b 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CompileCommandLine.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CompileCommandLine.java
@@ -45,7 +45,6 @@ public final class CompileCommandLine {
   @VisibleForTesting public final CcToolchainFeatures.Variables variables;
   private final String actionName;
   private final CppConfiguration cppConfiguration;
-  private final ImmutableList<String> unfilteredCompilerOptions;
 
   public CompileCommandLine(
       Artifact sourceFile,
@@ -58,8 +57,7 @@ public final class CompileCommandLine {
       CppConfiguration cppConfiguration,
       CcToolchainFeatures.Variables variables,
       String actionName,
-      DotdFile dotdFile,
-      ImmutableList<String> unfilteredCompilerOptions) {
+      DotdFile dotdFile) {
     this.sourceFile = Preconditions.checkNotNull(sourceFile);
     this.outputFile = Preconditions.checkNotNull(outputFile);
     this.sourceLabel = Preconditions.checkNotNull(sourceLabel);
@@ -71,7 +69,6 @@ public final class CompileCommandLine {
     this.variables = variables;
     this.actionName = actionName;
     this.dotdFile = isGenerateDotdFile(sourceFile) ? Preconditions.checkNotNull(dotdFile) : null;
-    this.unfilteredCompilerOptions = unfilteredCompilerOptions;
   }
 
   /** Returns true if Dotd file should be generated. */
@@ -164,7 +161,7 @@ public final class CompileCommandLine {
     // the user provided options, otherwise users adding include paths will not pick up their
     // own include paths first.
     if (!isObjcCompile(actionName)) {
-      options.addAll(unfilteredCompilerOptions);
+      options.addAll(toolchain.getUnfilteredCompilerOptions(features));
     }
 
     // Add the options of --per_file_copt, if the label or the base name of the source file
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 20fe8e030d..1b1884ce8d 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
@@ -217,8 +217,6 @@ public class CppCompileAction extends AbstractAction
   /** Whether this action needs to discover inputs. */
   private final boolean discoversInputs;
 
-  private final ImmutableList<PathFragment> builtInIncludeDirectories;
-
   /**
    * Set when the action prepares for execution. Used to preserve state between preparation and
    * execution.
@@ -273,8 +271,6 @@ public class CppCompileAction extends AbstractAction
    * @param actionName a string giving the name of this action for the purpose of toolchain
    *     evaluation
    * @param cppSemantics C++ compilation semantics
-   * @param unfilteredCompilerOptions - Compile options that will always be added.
-   * @param builtInIncludeDirectories - Directories to search for system includes from.
    */
   protected CppCompileAction(
       ActionOwner owner,
@@ -312,9 +308,7 @@ public class CppCompileAction extends AbstractAction
       ImmutableMap<String, String> environment,
       String actionName,
       Iterable<Artifact> builtinIncludeFiles,
-      CppSemantics cppSemantics,
-      ImmutableList<String> unfilteredCompilerOptions,
-      ImmutableList<PathFragment> builtInIncludeDirectories) {
+      CppSemantics cppSemantics) {
     super(
         owner,
         allInputs,
@@ -355,8 +349,7 @@ public class CppCompileAction extends AbstractAction
             cppConfiguration,
             variables,
             actionName,
-            dotdFile,
-            unfilteredCompilerOptions);
+            dotdFile);
     this.actionContext = actionContext;
     this.lipoScannables = lipoScannables;
     this.actionClassId = actionClassId;
@@ -370,7 +363,6 @@ public class CppCompileAction extends AbstractAction
     this.builtinIncludeFiles = ImmutableList.copyOf(builtinIncludeFiles);
     this.cppSemantics = cppSemantics;
     this.additionalIncludeScannables = ImmutableList.copyOf(additionalIncludeScannables);
-    this.builtInIncludeDirectories = builtInIncludeDirectories;
   }
 
   /**
@@ -389,7 +381,7 @@ public class CppCompileAction extends AbstractAction
 
   @Override
   public List<PathFragment> getBuiltInIncludeDirectories() {
-    return builtInIncludeDirectories;
+    return cppConfiguration.getBuiltInIncludeDirectories();
   }
 
   @Nullable
@@ -843,10 +835,9 @@ public class CppCompileAction extends AbstractAction
     if (optionalSourceFile != null) {
       allowedIncludes.add(optionalSourceFile);
     }
-    Iterable<PathFragment> ignoreDirs =
-        cppConfiguration.isStrictSystemIncludes()
-            ? getBuiltInIncludeDirectories()
-            : getValidationIgnoredDirs();
+    Iterable<PathFragment> ignoreDirs = cppConfiguration.isStrictSystemIncludes()
+        ? cppConfiguration.getBuiltInIncludeDirectories()
+        : getValidationIgnoredDirs();
 
     // Copy the sets to hash sets for fast contains checking.
     // Avoid immutable sets here to limit memory churn.
@@ -915,7 +906,7 @@ public class CppCompileAction extends AbstractAction
   }
 
   Iterable<PathFragment> getValidationIgnoredDirs() {
-    List<PathFragment> cxxSystemIncludeDirs = getBuiltInIncludeDirectories();
+    List<PathFragment> cxxSystemIncludeDirs = cppConfiguration.getBuiltInIncludeDirectories();
     return Iterables.concat(
         cxxSystemIncludeDirs, context.getSystemIncludeDirs());
   }
@@ -1268,8 +1259,9 @@ public class CppCompileAction extends AbstractAction
   }
 
   public List<Path> getPermittedSystemIncludePrefixes(Path execRoot) {
+    CppConfiguration toolchain = cppConfiguration;
     List<Path> systemIncludePrefixes = new ArrayList<>();
-    for (PathFragment includePath : getBuiltInIncludeDirectories()) {
+    for (PathFragment includePath : toolchain.getBuiltInIncludeDirectories()) {
       if (includePath.isAbsolute()) {
         systemIncludePrefixes.add(execRoot.getFileSystem().getPath(includePath));
       }
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppCompileActionBuilder.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppCompileActionBuilder.java
index e4bf2b3b4c..333361f193 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppCompileActionBuilder.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppCompileActionBuilder.java
@@ -386,8 +386,6 @@ public class CppCompileActionBuilder {
           getLipoScannables(realMandatoryInputs),
           ccToolchain.getBuiltinIncludeFiles(),
           cppSemantics,
-          ccToolchain.getUnfilteredCompilerOptions(features),
-          ccToolchain.getBuiltInIncludeDirectories(),
           ImmutableMap.copyOf(executionInfo));
     } else {
       return new CppCompileAction(
@@ -424,9 +422,7 @@ public class CppCompileActionBuilder {
           ImmutableMap.copyOf(environment),
           getActionName(),
           ccToolchain.getBuiltinIncludeFiles(),
-          cppSemantics,
-          ccToolchain.getUnfilteredCompilerOptions(features),
-          ccToolchain.getBuiltInIncludeDirectories());
+          cppSemantics);
     }
   }
 
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppConfiguration.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppConfiguration.java
index 765f4d6f6d..4388571311 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppConfiguration.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppConfiguration.java
@@ -25,10 +25,12 @@ import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Iterables;
 import com.google.common.collect.ListMultimap;
 import com.google.common.collect.Maps;
+import com.google.devtools.build.lib.analysis.RedirectChaser;
 import com.google.devtools.build.lib.analysis.RuleContext;
 import com.google.devtools.build.lib.analysis.config.BuildConfiguration;
 import com.google.devtools.build.lib.analysis.config.BuildOptions;
 import com.google.devtools.build.lib.analysis.config.CompilationMode;
+import com.google.devtools.build.lib.analysis.config.ConfigurationEnvironment;
 import com.google.devtools.build.lib.analysis.config.InvalidConfigurationException;
 import com.google.devtools.build.lib.analysis.config.PatchTransition;
 import com.google.devtools.build.lib.analysis.config.PerLabelOptions;
@@ -58,6 +60,7 @@ import com.google.devtools.build.lib.view.config.crosstool.CrosstoolConfig.CTool
 import com.google.devtools.build.lib.view.config.crosstool.CrosstoolConfig.LinkingModeFlags;
 import com.google.devtools.build.lib.view.config.crosstool.CrosstoolConfig.LipoMode;
 import com.google.devtools.build.lib.view.config.crosstool.CrosstoolConfig.ToolPath;
+import com.google.devtools.common.options.OptionsParsingException;
 import com.google.protobuf.TextFormat;
 import com.google.protobuf.TextFormat.ParseException;
 import java.io.Serializable;
@@ -159,6 +162,127 @@ public class CppConfiguration extends BuildConfiguration.Fragment {
     }
   }
 
+  /** Storage for the libc label, if given. */
+  public static class LibcTop implements Serializable {
+    private final Label label;
+
+    /**
+     * Result of trying to create LibcTop. Bundles whether or not it still needs values that aren't
+     * loaded yet.
+     */
+    public static class Result {
+      private final LibcTop libcTop;
+      private final boolean valuesMissing;
+
+      Result(LibcTop libcTop, boolean valuesMissing) {
+        this.libcTop = libcTop;
+        this.valuesMissing = valuesMissing;
+      }
+
+      @Nullable
+      public LibcTop getLibcTop() {
+        return libcTop;
+      }
+
+      public boolean valuesMissing() {
+        return valuesMissing;
+      }
+    };
+
+    /** Tries to create a LibcTop object and returns whether or not all were any missing values. */
+    public static LibcTop.Result createLibcTop(
+        CppOptions cppOptions, ConfigurationEnvironment env, CrosstoolConfig.CToolchain toolchain)
+        throws InterruptedException, InvalidConfigurationException {
+      Preconditions.checkArgument(env != null);
+
+      PathFragment defaultSysroot =
+          toolchain.getBuiltinSysroot().length() == 0
+              ? null
+              : PathFragment.create(toolchain.getBuiltinSysroot());
+      if ((defaultSysroot != null) && !defaultSysroot.isNormalized()) {
+        throw new InvalidConfigurationException(
+            "The built-in sysroot '" + defaultSysroot + "' is not normalized.");
+      }
+
+      if ((cppOptions.libcTopLabel != null) && (defaultSysroot == null)) {
+        throw new InvalidConfigurationException(
+            "The selected toolchain "
+                + toolchain.getToolchainIdentifier()
+                + " does not support setting --grte_top.");
+      }
+
+      LibcTop libcTop = null;
+      if (cppOptions.libcTopLabel != null) {
+        libcTop = createLibcTop(cppOptions.libcTopLabel, env);
+        if (libcTop == null) {
+          return new Result(libcTop, true);
+        }
+      } else if (!toolchain.getDefaultGrteTop().isEmpty()) {
+        Label grteTopLabel = null;
+        try {
+          grteTopLabel =
+              new CppOptions.LibcTopLabelConverter().convert(toolchain.getDefaultGrteTop());
+        } catch (OptionsParsingException e) {
+          throw new InvalidConfigurationException(e.getMessage(), e);
+        }
+
+        libcTop = createLibcTop(grteTopLabel, env);
+        if (libcTop == null) {
+          return new Result(libcTop, true);
+        }
+      }
+      return new Result(libcTop, false);
+    }
+
+    @Nullable
+    private static LibcTop createLibcTop(Label label, ConfigurationEnvironment env)
+        throws InvalidConfigurationException, InterruptedException {
+      Preconditions.checkArgument(label != null);
+      Label trueLabel = label;
+      // Allow the sysroot to follow any redirects.
+      trueLabel = RedirectChaser.followRedirects(env, label, "libc_top");
+      if (trueLabel == null) {
+        // Happens if there's a reference to package that hasn't been loaded yet.
+        return null;
+      }
+      return new LibcTop(trueLabel);
+    }
+
+    private LibcTop(Label label) {
+      Preconditions.checkArgument(label != null);
+      this.label = label;
+    }
+
+    public Label getLabel() {
+      return label;
+    }
+
+    public PathFragment getSysroot() {
+      return label.getPackageFragment();
+    }
+
+    @Override
+    public String toString() {
+      return label.toString();
+    }
+
+    @Override
+    public boolean equals(Object other) {
+      if (this == other) {
+        return true;
+      } else if (other instanceof LibcTop) {
+        return label.equals(((LibcTop) other).label);
+      } else {
+        return false;
+      }
+    }
+
+    @Override
+    public int hashCode() {
+      return label.hashCode();
+    }
+  }
+
   /**
    * This macro will be passed as a command-line parameter (eg. -DBUILD_FDO_TYPE="LIPO").
    * For possible values see {@code CppModel.getFdoBuildStamp()}.
@@ -257,17 +381,15 @@ public class CppConfiguration extends BuildConfiguration.Fragment {
 
   // TODO(bazel-team): All these labels (except for ccCompilerRuleLabel) can be removed once the
   // transition to the cc_compiler rule is complete.
+  private final Label libcLabel;
   private final Label staticRuntimeLibsLabel;
   private final Label dynamicRuntimeLibsLabel;
   private final Label ccToolchainLabel;
   private final Label stlLabel;
 
-  // TODO(kmensah): This is temporary until all the Skylark functions that need this can be removed.
-  private final PathFragment nonConfiguredSysroot;
-  private final Label sysrootLabel;
-  private final PathFragment defaultSysroot;
+  private final PathFragment sysroot;
   private final PathFragment runtimeSysroot;
-  private final ImmutableList<String> rawBuiltInIncludeDirectories;
+  private final ImmutableList<PathFragment> builtInIncludeDirectories;
 
   private final Map<String, PathFragment> toolPaths;
   private final PathFragment ldExecutable;
@@ -492,14 +614,29 @@ public class CppConfiguration extends BuildConfiguration.Fragment {
     this.abiGlibcVersion = toolchain.getAbiLibcVersion();
 
     // The default value for optional string attributes is the empty string.
-    this.defaultSysroot = computeDefaultSysroot(toolchain);
+    PathFragment defaultSysroot = toolchain.getBuiltinSysroot().length() == 0
+        ? null
+        : PathFragment.create(toolchain.getBuiltinSysroot());
+    if ((defaultSysroot != null) && !defaultSysroot.isNormalized()) {
+      throw new IllegalArgumentException("The built-in sysroot '" + defaultSysroot
+          + "' is not normalized.");
+    }
 
-    this.sysrootLabel = params.sysrootLabel;
-    this.nonConfiguredSysroot =
-        params.sysrootLabel == null ? defaultSysroot : params.sysrootLabel.getPackageFragment();
+    LibcTop libcTop = params.libcTop;
+    if ((libcTop != null) && (libcTop.getLabel() != null)) {
+      libcLabel = libcTop.getLabel();
+    } else {
+      libcLabel = null;
+    }
 
-    rawBuiltInIncludeDirectories =
-        ImmutableList.copyOf(toolchain.getCxxBuiltinIncludeDirectoryList());
+    ImmutableList.Builder<PathFragment> builtInIncludeDirectoriesBuilder
+        = ImmutableList.builder();
+    sysroot = libcTop == null ? defaultSysroot : libcTop.getSysroot();
+    for (String s : toolchain.getCxxBuiltinIncludeDirectoryList()) {
+      builtInIncludeDirectoriesBuilder.add(
+          resolveIncludeDir(s, sysroot, crosstoolTopPathFragment));
+    }
+    builtInIncludeDirectories = builtInIncludeDirectoriesBuilder.build();
 
     // The runtime sysroot should really be set from --grte_top. However, currently libc has no
     // way to set the sysroot. The CROSSTOOL file does set the runtime sysroot, in the
@@ -507,8 +644,17 @@ public class CppConfiguration extends BuildConfiguration.Fragment {
     // and libc versions, you must always choose compatible ones.
     runtimeSysroot = defaultSysroot;
 
-    ImmutableList.Builder<String> unfilteredCoptsBuilder = ImmutableList.builder();
+    String sysrootFlag;
+    if (sysroot != null) {
+      sysrootFlag = "--sysroot=" + sysroot;
+    } else {
+      sysrootFlag = null;
+    }
 
+    ImmutableList.Builder<String> unfilteredCoptsBuilder = ImmutableList.builder();
+    if (sysrootFlag != null) {
+      unfilteredCoptsBuilder.add(sysrootFlag);
+    }
     unfilteredCoptsBuilder.addAll(toolchain.getUnfilteredCxxFlagList());
     unfilteredCompilerFlags = new FlagList(
         unfilteredCoptsBuilder.build(),
@@ -520,6 +666,9 @@ public class CppConfiguration extends BuildConfiguration.Fragment {
     if (cppOptions.experimentalOmitfp) {
       linkoptsBuilder.add("-Wl,--eh-frame-hdr");
     }
+    if (sysrootFlag != null) {
+      linkoptsBuilder.add(sysrootFlag);
+    }
     this.linkOptions = linkoptsBuilder.build();
 
     ImmutableList.Builder<String> ltoindexoptsBuilder = ImmutableList.builder();
@@ -581,6 +730,12 @@ public class CppConfiguration extends BuildConfiguration.Fragment {
     for (CrosstoolConfig.MakeVariable variable : toolchain.getMakeVariableList()) {
       makeVariablesBuilder.put(variable.getName(), variable.getValue());
     }
+    // TODO(kmensah): Remove once targets can depend on the cc_toolchain in skylark.
+    if (sysrootFlag != null) {
+      String ccFlags = makeVariablesBuilder.get("CC_FLAGS");
+      ccFlags = ccFlags.isEmpty() ? sysrootFlag : ccFlags + " " + sysrootFlag;
+      makeVariablesBuilder.put("CC_FLAGS", ccFlags);
+    }
     this.additionalMakeVariables = ImmutableMap.copyOf(makeVariablesBuilder);
   }
 
@@ -1123,6 +1278,14 @@ public class CppConfiguration extends BuildConfiguration.Fragment {
   }
 
   /**
+   * Returns a label that forms a dependency to the files required for the
+   * sysroot that is used.
+   */
+  public Label getLibcLabel() {
+    return libcLabel;
+  }
+
+  /**
    * Returns a label that references the library files needed to statically
    * link the C++ runtime (i.e. libgcc.a, libgcc_eh.a, libstdc++.a) for the
    * target architecture.
@@ -1270,30 +1433,17 @@ public class CppConfiguration extends BuildConfiguration.Fragment {
   }
 
   /**
-   * Returns the built-in list of system include paths for the toolchain compiler. All paths in this
-   * list should be relative to the exec directory. They may be absolute if they are also installed
-   * on the remote build nodes or for local compilation.
+   * Returns the built-in list of system include paths for the toolchain
+   * compiler. All paths in this list should be relative to the exec directory.
+   * They may be absolute if they are also installed on the remote build nodes or
+   * for local compilation.
    */
-  @SkylarkCallable(
-    name = "built_in_include_directories",
-    structField = true,
-    doc =
-        "Built-in system include paths for the toolchain compiler. All paths in this list"
-            + " should be relative to the exec directory. They may be absolute if they are also"
-            + " installed on the remote build nodes or for local compilation."
-  )
-  public ImmutableList<PathFragment> getBuiltInIncludeDirectories()
-      throws InvalidConfigurationException {
-    return getBuiltInIncludeDirectories(nonConfiguredSysroot);
-  }
-
-  public ImmutableList<PathFragment> getBuiltInIncludeDirectories(PathFragment sysroot)
-      throws InvalidConfigurationException {
-    ImmutableList.Builder<PathFragment> builtInIncludeDirectoriesBuilder = ImmutableList.builder();
-    for (String s : rawBuiltInIncludeDirectories) {
-      builtInIncludeDirectoriesBuilder.add(resolveIncludeDir(s, sysroot, crosstoolTopPathFragment));
-    }
-    return builtInIncludeDirectoriesBuilder.build();
+  @SkylarkCallable(name = "built_in_include_directories", structField = true,
+      doc = "Built-in system include paths for the toolchain compiler. All paths in this list"
+      + " should be relative to the exec directory. They may be absolute if they are also installed"
+      + " on the remote build nodes or for local compilation.")
+  public ImmutableList<PathFragment> getBuiltInIncludeDirectories() {
+    return builtInIncludeDirectories;
   }
 
   /**
@@ -1306,11 +1456,7 @@ public class CppConfiguration extends BuildConfiguration.Fragment {
       + "different sysroots, or the sysroot is the same as the default sysroot, then "
       + "this method returns <code>None</code>.")
   public PathFragment getSysroot() {
-    return nonConfiguredSysroot;
-  }
-
-  public Label getSysrootLabel() {
-    return sysrootLabel;
+    return sysroot;
   }
 
   /**
@@ -1370,8 +1516,8 @@ public class CppConfiguration extends BuildConfiguration.Fragment {
   }
 
   /**
-   * Returns the default list of options which cannot be filtered by BUILD rules. These should be
-   * appended to the command line after filtering.
+   * Returns the default list of options which cannot be filtered by BUILD
+   * rules. These should be appended to the command line after filtering.
    */
   @SkylarkCallable(
     name = "unfiltered_compiler_options",
@@ -1380,56 +1526,21 @@ public class CppConfiguration extends BuildConfiguration.Fragment {
             + "rules. These should be appended to the command line after filtering."
   )
   public ImmutableList<String> getUnfilteredCompilerOptions(Iterable<String> features) {
-    return getUnfilteredCompilerOptions(features, nonConfiguredSysroot);
-  }
-
-  public ImmutableList<String> getUnfilteredCompilerOptions(
-      Iterable<String> features, PathFragment sysroot) {
-    if (sysroot == null) {
-      return unfilteredCompilerFlags.evaluate(features);
-    } else {
-      return ImmutableList.<String>builder()
-          .add("--sysroot=" + sysroot)
-          .addAll(unfilteredCompilerFlags.evaluate(features))
-          .build();
-    }
+    return unfilteredCompilerFlags.evaluate(features);
   }
 
   /**
-   * Returns the set of command-line linker options, including any flags inferred from the
-   * command-line options.
+   * Returns the set of command-line linker options, including any flags
+   * inferred from the command-line options.
    *
    * @see Link
    */
   // TODO(bazel-team): Clean up the linker options computation!
-  @SkylarkCallable(
-    name = "link_options",
-    structField = true,
-    doc =
-        "Returns the set of command-line linker options, including any flags "
-            + "inferred from the command-line options."
-  )
+  @SkylarkCallable(name = "link_options", structField = true,
+      doc = "Returns the set of command-line linker options, including any flags "
+      + "inferred from the command-line options.")
   public ImmutableList<String> getLinkOptions() {
-    return getLinkOptions(nonConfiguredSysroot);
-  }
-
-  public ImmutableList<String> getLinkOptions(PathFragment sysroot) {
-    if (sysroot == null) {
-      return linkOptions;
-    } else {
-      return ImmutableList.<String>builder()
-          .addAll(linkOptions)
-          .add("--sysroot=" + sysroot)
-          .build();
-    }
-  }
-
-  public boolean hasStaticLinkOption() {
-    return linkOptions.contains("-static");
-  }
-
-  public boolean hasSharedLinkOption() {
-    return linkOptions.contains("-shared");
+    return linkOptions;
   }
 
   /** Returns the set of command-line LTO indexing options. */
@@ -2059,8 +2170,6 @@ public class CppConfiguration extends BuildConfiguration.Fragment {
     // TODO(bazel-team): delete all of these.
     globalMakeEnvBuilder.put("CROSSTOOLTOP", crosstoolTopPathFragment.getPathString());
 
-    // TODO(kmensah): Remove when skylark dependencies can be updated to rely on
-    // CcToolchainProvider.
     globalMakeEnvBuilder.putAll(getAdditionalMakeVariables());
 
     globalMakeEnvBuilder.put("ABI_GLIBC_VERSION", getAbiGlibcVersion());
@@ -2143,22 +2252,6 @@ public class CppConfiguration extends BuildConfiguration.Fragment {
     return requestedFeatures.build();
   }
 
-  public static PathFragment computeDefaultSysroot(CToolchain toolchain) {
-    PathFragment defaultSysroot =
-        toolchain.getBuiltinSysroot().length() == 0
-            ? null
-            : PathFragment.create(toolchain.getBuiltinSysroot());
-    if ((defaultSysroot != null) && !defaultSysroot.isNormalized()) {
-      throw new IllegalArgumentException(
-          "The built-in sysroot '" + defaultSysroot + "' is not normalized.");
-    }
-    return defaultSysroot;
-  }
-
-  public PathFragment getDefaultSysroot() {
-    return defaultSysroot;
-  }
-
   @Override
   public PatchTransition getArtifactOwnerTransition() {
     return isLipoContextCollector() ? ContextCollectorOwnerTransition.INSTANCE : null;
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppConfigurationLoader.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppConfigurationLoader.java
index b334b10923..9a98181724 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppConfigurationLoader.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppConfigurationLoader.java
@@ -36,11 +36,10 @@ import com.google.devtools.build.lib.packages.NoSuchThingException;
 import com.google.devtools.build.lib.packages.NonconfigurableAttributeMapper;
 import com.google.devtools.build.lib.packages.Rule;
 import com.google.devtools.build.lib.packages.Target;
+import com.google.devtools.build.lib.rules.cpp.CppConfiguration.LibcTop;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
 import com.google.devtools.build.lib.vfs.Path;
-import com.google.devtools.build.lib.vfs.PathFragment;
 import com.google.devtools.build.lib.view.config.crosstool.CrosstoolConfig;
-import com.google.devtools.common.options.OptionsParsingException;
 import javax.annotation.Nullable;
 
 /**
@@ -90,7 +89,7 @@ public class CppConfigurationLoader implements ConfigurationFragmentFactory {
     protected final Label ccToolchainLabel;
     protected final Label stlLabel;
     protected final Path fdoZip;
-    protected final Label sysrootLabel;
+    protected final LibcTop libcTop;
 
     CppConfigurationParameters(
         CrosstoolConfig.CToolchain toolchain,
@@ -100,7 +99,7 @@ public class CppConfigurationLoader implements ConfigurationFragmentFactory {
         Label crosstoolTop,
         Label ccToolchainLabel,
         Label stlLabel,
-        Label sysrootLabel) {
+        LibcTop libcTop) {
       this.toolchain = toolchain;
       this.cacheKeySuffix = cacheKeySuffix;
       this.commonOptions = buildOptions.get(BuildConfiguration.Options.class);
@@ -109,7 +108,7 @@ public class CppConfigurationLoader implements ConfigurationFragmentFactory {
       this.crosstoolTop = crosstoolTop;
       this.ccToolchainLabel = ccToolchainLabel;
       this.stlLabel = stlLabel;
-      this.sysrootLabel = sysrootLabel;
+      this.libcTop = libcTop;
     }
   }
 
@@ -220,7 +219,10 @@ public class CppConfigurationLoader implements ConfigurationFragmentFactory {
           "The label '%s' is not a cc_toolchain rule", ccToolchainLabel));
     }
 
-    Label sysrootLabel = getSysrootLabel(toolchain, cppOptions.libcTopLabel);
+    LibcTop.Result libcTopResult = LibcTop.createLibcTop(cppOptions, env, toolchain);
+    if (libcTopResult.valuesMissing()) {
+      return null;
+    }
 
     return new CppConfigurationParameters(
         toolchain,
@@ -230,34 +232,6 @@ public class CppConfigurationLoader implements ConfigurationFragmentFactory {
         crosstoolTopLabel,
         ccToolchainLabel,
         stlLabel,
-        sysrootLabel);
-  }
-
-  @Nullable
-  public static Label getSysrootLabel(CrosstoolConfig.CToolchain toolchain, Label libcTopLabel)
-      throws InvalidConfigurationException {
-    PathFragment defaultSysroot = CppConfiguration.computeDefaultSysroot(toolchain);
-
-    if ((libcTopLabel != null) && (defaultSysroot == null)) {
-      throw new InvalidConfigurationException(
-          "The selected toolchain "
-              + toolchain.getToolchainIdentifier()
-              + " does not support setting --grte_top.");
-    }
-
-    if (libcTopLabel != null) {
-      return libcTopLabel;
-    }
-
-    if (!toolchain.getDefaultGrteTop().isEmpty()) {
-      try {
-        Label grteTopLabel =
-            new CppOptions.LibcTopLabelConverter().convert(toolchain.getDefaultGrteTop());
-        return grteTopLabel;
-      } catch (OptionsParsingException e) {
-        throw new InvalidConfigurationException(e.getMessage(), e);
-      }
-    }
-    return null;
+        libcTopResult.getLibcTop());
   }
 }
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppHelper.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppHelper.java
index ea3fd42ddd..aa719c80ed 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppHelper.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppHelper.java
@@ -592,7 +592,7 @@ public class CppHelper {
   public static void maybeAddStaticLinkMarkerProvider(RuleConfiguredTargetBuilder builder,
       RuleContext ruleContext) {
     boolean staticallyLinked = false;
-    if (ruleContext.getFragment(CppConfiguration.class).hasStaticLinkOption()) {
+    if (ruleContext.getFragment(CppConfiguration.class).getLinkOptions().contains("-static")) {
       staticallyLinked = true;
     } else if (ruleContext.attributes().has("linkopts", Type.STRING_LIST)
         && ruleContext.attributes().get("linkopts", Type.STRING_LIST).contains("-static")) {
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppLinkActionBuilder.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppLinkActionBuilder.java
index 18d7102092..0c640ff818 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppLinkActionBuilder.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppLinkActionBuilder.java
@@ -813,7 +813,7 @@ public class CppLinkActionBuilder {
     } else if (isLTOIndexing && allLTOArtifacts != null) {
       for (LTOBackendArtifacts a : allLTOArtifacts) {
         List<String> argv = new ArrayList<>();
-        argv.addAll(toolchain.getLinkOptions());
+        argv.addAll(cppConfiguration.getLinkOptions());
         argv.addAll(cppConfiguration.getCompilerOptions(features));
         a.setCommandLine(argv);
 
@@ -914,7 +914,7 @@ public class CppLinkActionBuilder {
     boolean sharedLinkopts =
         type == LinkTargetType.DYNAMIC_LIBRARY
             || linkopts.contains("-shared")
-            || cppConfig.hasSharedLinkOption();
+            || cppConfig.getLinkOptions().contains("-shared");
     return (isNativeDeps || cppConfig.legacyWholeArchive())
         && (fullyStatic || mostlyStatic)
         && sharedLinkopts;
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/FakeCppCompileAction.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/FakeCppCompileAction.java
index 1844609dd1..f35954589d 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/FakeCppCompileAction.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/FakeCppCompileAction.java
@@ -82,8 +82,6 @@ public class FakeCppCompileAction extends CppCompileAction {
       Iterable<IncludeScannable> lipoScannables,
       Iterable<Artifact> builtinIncludeFiles,
       CppSemantics cppSemantics,
-      ImmutableList<String> unfilteredCompilerOptions,
-      ImmutableList<PathFragment> builtInIncludeDirectories,
       ImmutableMap<String, String> executionInfo) {
     super(
         owner,
@@ -126,9 +124,7 @@ public class FakeCppCompileAction extends CppCompileAction {
         ImmutableMap.<String, String>of(),
         CppCompileAction.CPP_COMPILE,
         builtinIncludeFiles,
-        cppSemantics,
-        unfilteredCompilerOptions,
-        builtInIncludeDirectories);
+        cppSemantics);
     this.tempOutputFile = Preconditions.checkNotNull(tempOutputFile);
   }
 
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/LinkCommandLine.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/LinkCommandLine.java
index 491e481322..bbb3b4ddb8 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/LinkCommandLine.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/LinkCommandLine.java
@@ -74,7 +74,6 @@ public final class LinkCommandLine extends CommandLine {
   @Nullable private final PathFragment runtimeSolibDir;
   private final boolean nativeDeps;
   private final boolean useTestOnlyFlags;
-  private final CcToolchainProvider ccProvider;
 
   @Nullable private final Artifact paramFile;
 
@@ -99,8 +98,7 @@ public final class LinkCommandLine extends CommandLine {
       boolean useTestOnlyFlags,
       @Nullable Artifact paramFile,
       CcToolchainFeatures.Variables variables,
-      @Nullable FeatureConfiguration featureConfiguration,
-      CcToolchainProvider ccProvider) {
+      @Nullable FeatureConfiguration featureConfiguration) {
 
     this.actionName = actionName;
     this.toolPath = toolPath;
@@ -127,7 +125,6 @@ public final class LinkCommandLine extends CommandLine {
     this.nativeDeps = nativeDeps;
     this.useTestOnlyFlags = useTestOnlyFlags;
     this.paramFile = paramFile;
-    this.ccProvider = ccProvider;
   }
 
   @Nullable
@@ -325,7 +322,7 @@ public final class LinkCommandLine extends CommandLine {
     boolean sharedLinkopts =
         linkTargetType == LinkTargetType.DYNAMIC_LIBRARY
             || linkopts.contains("-shared")
-            || cppConfiguration.hasSharedLinkOption();
+            || cppConfiguration.getLinkOptions().contains("-shared");
 
     List<String> toolchainFlags = new ArrayList<>();
 
@@ -356,7 +353,7 @@ public final class LinkCommandLine extends CommandLine {
       toolchainFlags.addAll(cppConfiguration.getTestOnlyLinkOptions());
     }
 
-    toolchainFlags.addAll(ccProvider.getLinkOptions());
+    toolchainFlags.addAll(cppConfiguration.getLinkOptions());
 
     // -pie is not compatible with shared and should be
     // removed when the latter is part of the link command. Should we need to further
@@ -575,7 +572,7 @@ public final class LinkCommandLine extends CommandLine {
       optionList.add("-I.");
 
       // Add sysroot.
-      PathFragment sysroot = ccProvider.getSysroot();
+      PathFragment sysroot = cppConfiguration.getSysroot();
       if (sysroot != null) {
         optionList.add("--sysroot=" + sysroot.getPathString());
       }
@@ -583,7 +580,7 @@ public final class LinkCommandLine extends CommandLine {
       // Add toolchain compiler options.
       optionList.addAll(cppConfiguration.getCompilerOptions(features));
       optionList.addAll(cppConfiguration.getCOptions());
-      optionList.addAll(ccProvider.getUnfilteredCompilerOptions(features));
+      optionList.addAll(cppConfiguration.getUnfilteredCompilerOptions(features));
       if (CppFileTypes.CPP_SOURCE.matches(linkstamp.getKey().getExecPath())) {
         optionList.addAll(cppConfiguration.getCxxOptions(features));
       }
@@ -637,7 +634,7 @@ public final class LinkCommandLine extends CommandLine {
 
     private final BuildConfiguration configuration;
     private final ActionOwner owner;
-    private final RuleContext ruleContext;
+    @Nullable private final RuleContext ruleContext;
 
     @Nullable private String toolPath;
     @Nullable private Artifact output;
@@ -654,7 +651,7 @@ public final class LinkCommandLine extends CommandLine {
     private boolean nativeDeps;
     private boolean useTestOnlyFlags;
     @Nullable private Artifact paramFile;
-    private CcToolchainProvider toolchain;
+    @Nullable private CcToolchainProvider toolchain;
     private FdoSupport fdoSupport;
     private Variables variables;
     private FeatureConfiguration featureConfiguration;
@@ -662,7 +659,8 @@ public final class LinkCommandLine extends CommandLine {
     // This interface is needed to support tests that don't create a
     // ruleContext, in which case the configuration and action owner
     // cannot be accessed off of the give ruleContext.
-    public Builder(BuildConfiguration configuration, ActionOwner owner, RuleContext ruleContext) {
+    public Builder(
+        BuildConfiguration configuration, ActionOwner owner, @Nullable RuleContext ruleContext) {
       this.configuration = configuration;
       this.owner = owner;
       this.ruleContext = ruleContext;
@@ -691,16 +689,17 @@ public final class LinkCommandLine extends CommandLine {
             Iterables.concat(DEFAULT_LINKSTAMP_OPTIONS, linkstampCompileOptions));
       }
 
-      if (toolchain == null) {
-        toolchain =
-            Preconditions.checkNotNull(CppHelper.getToolchain(ruleContext, ":cc_toolchain"));
-      }
-
       // The ruleContext can be null for some tests.
       if (ruleContext != null) {
         if (featureConfiguration == null) {
-          featureConfiguration =
-              CcCommon.configureFeatures(ruleContext, toolchain, CcLibraryHelper.SourceCategory.CC);
+          if (toolchain != null) {
+            featureConfiguration =
+                CcCommon.configureFeatures(
+                    ruleContext, toolchain, CcLibraryHelper.SourceCategory.CC);
+          } else {
+            CcToolchainProvider ccToolchain = CppHelper.getToolchain(ruleContext, ":cc_toolchain");
+            featureConfiguration = CcCommon.configureFeatures(ruleContext, ccToolchain);
+          }
         }
 
         if (fdoSupport == null) {
@@ -735,8 +734,7 @@ public final class LinkCommandLine extends CommandLine {
           useTestOnlyFlags,
           paramFile,
           variables,
-          featureConfiguration,
-          toolchain);
+          featureConfiguration);
     }
 
     /**