Remove support for thin archives.

--
MOS_MIGRATED_REVID=130938527

5 files changed, 10 insertions, 49 deletions

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 ae9218d134..70af928677 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
@@ -271,7 +271,6 @@ public class CppConfiguration extends BuildConfiguration.Fragment {
 
   private final CcToolchainFeatures toolchainFeatures;
   private final boolean supportsGoldLinker;
-  private final boolean supportsThinArchives;
   private final boolean supportsStartEndLib;
   private final boolean supportsDynamicLinker;
   private final boolean supportsInterfaceSharedObjects;
@@ -324,7 +323,6 @@ public class CppConfiguration extends BuildConfiguration.Fragment {
   private final ImmutableList<String> objcopyOptions;
   private final ImmutableList<String> ldOptions;
   private final ImmutableList<String> arOptions;
-  private final ImmutableList<String> arThinArchivesOptions;
 
   private final ImmutableMap<String, String> additionalMakeVariables;
 
@@ -409,7 +407,6 @@ public class CppConfiguration extends BuildConfiguration.Fragment {
     toolchain = addLegacyFeatures(toolchain);
     this.toolchainFeatures = new CcToolchainFeatures(toolchain);
     this.supportsGoldLinker = toolchain.getSupportsGoldLinker();
-    this.supportsThinArchives = toolchain.getSupportsThinArchives();
     this.supportsStartEndLib = toolchain.getSupportsStartEndLib();
     this.supportsInterfaceSharedObjects = toolchain.getSupportsInterfaceSharedObjects();
     this.supportsEmbeddedRuntimes = toolchain.getSupportsEmbeddedRuntimes();
@@ -515,8 +512,6 @@ public class CppConfiguration extends BuildConfiguration.Fragment {
     this.objcopyOptions = ImmutableList.copyOf(toolchain.getObjcopyEmbedFlagList());
     this.ldOptions = ImmutableList.copyOf(toolchain.getLdEmbedFlagList());
     this.arOptions = copyOrDefaultIfEmpty(toolchain.getArFlagList(), "rcsD");
-    this.arThinArchivesOptions = copyOrDefaultIfEmpty(
-        toolchain.getArThinArchivesFlagList(), "rcsDT");
 
     this.abi = toolchain.getAbiVersion();
     this.abiGlibcVersion = toolchain.getAbiLibcVersion();
@@ -1239,13 +1234,6 @@ public class CppConfiguration extends BuildConfiguration.Fragment {
   }
 
   /**
-   * Returns whether the toolchain supports thin archives.
-   */
-  public boolean supportsThinArchives() {
-    return supportsThinArchives;
-  }
-
-  /**
    * Returns whether the toolchain supports the --start-lib/--end-lib options.
    */
   public boolean supportsStartEndLib() {
@@ -1311,20 +1299,14 @@ public class CppConfiguration extends BuildConfiguration.Fragment {
    * Returns the type of archives being used.
    */
   public Link.ArchiveType archiveType() {
-    if (useStartEndLib()) {
-      return Link.ArchiveType.START_END_LIB;
-    }
-    if (useThinArchives()) {
-      return Link.ArchiveType.THIN;
-    }
-    return Link.ArchiveType.FAT;
+    return useStartEndLib() ? Link.ArchiveType.START_END_LIB : Link.ArchiveType.REGULAR;
   }
 
   /**
    * Returns the ar flags to be used.
    */
-  public ImmutableList<String> getArFlags(boolean thinArchives) {
-    return thinArchives ? arThinArchivesOptions : arOptions;
+  public ImmutableList<String> getArFlags() {
+    return arOptions;
   }
 
   /**
@@ -1707,10 +1689,6 @@ public class CppConfiguration extends BuildConfiguration.Fragment {
     return cppOptions.useStartEndLib && supportsStartEndLib();
   }
 
-  public boolean useThinArchives() {
-    return cppOptions.useThinArchives && supportsThinArchives();
-  }
-
   /**
    * Returns true if interface shared objects should be used.
    */
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppOptions.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppOptions.java
index 47cd385670..0b7b82c193 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppOptions.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppOptions.java
@@ -173,16 +173,6 @@ public class CppOptions extends FragmentOptions {
   )
   public String glibc;
 
-  @Option(
-    name = "thin_archives",
-    defaultValue = "false",
-    category = "strategy", // but also adds edges to the action graph
-    help =
-        "Pass the 'T' flag to ar if supported by the toolchain. "
-            + "All supported toolchains support this setting."
-  )
-  public boolean useThinArchives;
-
   // O intrepid reaper of unused options: Be warned that the [no]start_end_lib
   // option, however tempting to remove, has a use case. Look in our telemetry data.
   @Option(
@@ -581,7 +571,6 @@ public class CppOptions extends FragmentOptions {
     // -g0 first and let the user options override it.
     host.coptList = ImmutableList.<String>builder().add("-g0").addAll(hostCoptList).build();
 
-    host.useThinArchives = useThinArchives;
     host.useStartEndLib = useStartEndLib;
     host.stripBinaries = StripMode.ALWAYS;
     host.fdoOptimize = null;
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/Link.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/Link.java
index f03f128199..ec51c8413f 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/Link.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/Link.java
@@ -60,10 +60,6 @@ public abstract class Link {
       CppFileTypes.VERSIONED_SHARED_LIBRARY,
       CppFileTypes.INTERFACE_SHARED_LIBRARY);
 
-  /**
-   * These need special handling when --thin_archive is true. {@link CppLinkAction} checks that
-   * these files are never added as non-libraries.
-   */
   public static final FileTypeSet ARCHIVE_LIBRARY_FILETYPES = FileTypeSet.of(
       CppFileTypes.ARCHIVE,
       CppFileTypes.PIC_ARCHIVE,
@@ -239,12 +235,11 @@ public abstract class Link {
   }
 
   /**
-   * Types of archive.
+   * How to pass archives to the linker on the command line.
    */
   public enum ArchiveType {
-    FAT,            // Regular archive that includes its members.
-    THIN,           // Thin archive that just points to its members.
-    START_END_LIB   // A --start-lib ... --end-lib group in the command line.
+    REGULAR,        // Put the archive itself on the linker command line.
+    START_END_LIB   // Put the object files enclosed by --start-lib / --end-lib on the command line
   }
 
   static boolean useStartEndLib(LinkerInput linkerInput, ArchiveType archiveType) {
@@ -331,7 +326,7 @@ public abstract class Link {
         // start_end_lib archive (aka static library). Also check if the library contains object
         // files - otherwise getObjectFiles returns null, which would lead to an NPE in
         // simpleLinkerInputs.
-        boolean needMembersForLink = archiveType != ArchiveType.FAT
+        boolean needMembersForLink = archiveType != ArchiveType.REGULAR
             && (inputLibrary.getArtifactCategory() == ArtifactCategory.STATIC_LIBRARY
                 || inputLibrary.getArtifactCategory() == ArtifactCategory.ALWAYSLINK_STATIC_LIBRARY)
             && inputLibrary.containsObjectFiles();
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 b3a0cc7d09..bb4826e242 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
@@ -433,8 +433,7 @@ public final class LinkCommandLine extends CommandLine {
         // The static library link command follows this template:
         // ar <cmd> <output_archive> <input_files...>
         argv.add(cppConfiguration.getArExecutable().getPathString());
-        argv.addAll(
-            cppConfiguration.getArFlags(cppConfiguration.archiveType() == Link.ArchiveType.THIN));
+        argv.addAll(cppConfiguration.getArFlags());
         argv.add(output.getExecPathString());
         argv.addAll(featureConfiguration.getCommandLine(actionName, variables));
         argv.addAll(noWholeArchiveFlags);
diff --git a/src/main/protobuf/crosstool_config.proto b/src/main/protobuf/crosstool_config.proto
index 0ce4984b8f..295426f8c4 100644
--- a/src/main/protobuf/crosstool_config.proto
+++ b/src/main/protobuf/crosstool_config.proto
@@ -303,6 +303,7 @@ message CToolchain {
   // Feature flags.
   // TODO(bazel-team): Sink those into 'Feature' instances.
   optional bool supports_gold_linker = 10 [default = false];
+  // Legacy field, ignored by Bazel.
   optional bool supports_thin_archives = 11 [default = false];
   optional bool supports_start_end_lib = 28 [default = false];
   optional bool supports_interface_shared_objects = 32 [default = false];
@@ -347,8 +348,7 @@ message CToolchain {
   // Ar flags for combining object files into archives. If this is not set, it
   // defaults to "rcsD".
   repeated string ar_flag = 47;
-  // Ar flags for combining object files into archives when thin_archives is
-  // enabled. If this is not set, it defaults to "rcsDT".
+  // Legacy field, ignored by Bazel.
   repeated string ar_thin_archives_flag = 48;
   // Additional compiler flags that are added for cc_plugin rules of type 'gcc'
   repeated string gcc_plugin_compiler_flag = 34;