Add a fast path for validating include directives. Most -isystem dire…

…ctives are

actually added for cc_library's include-attribute. For these, the same path is
present on the command line, but also ignored. For N of those directives, we
currently do O(N^2) prefix checks, which is unnecessarily expensive.

RELNOTES: None.
PiperOrigin-RevId: 196477307

src/main/java/com/google/devtools/build/lib/rules/cpp/CppCompileActionBuilder.java

@@ -19,6 +19,7 @@
 import com.google.common.base.Predicates;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Iterables;
 import com.google.devtools.build.lib.actions.ActionOwner;
 import com.google.devtools.build.lib.actions.Artifact;
@@ -481,7 +482,7 @@ private boolean shouldPruneModules() {
   }
 
   private void verifyActionIncludePaths(CppCompileAction action, Consumer<String> errorReporter) {
-    Iterable<PathFragment> ignoredDirs = action.getValidationIgnoredDirs();
+    ImmutableSet<PathFragment> ignoredDirs = ImmutableSet.copyOf(action.getValidationIgnoredDirs());
     // We currently do not check the output of:
     // - getQuoteIncludeDirs(): those only come from includes attributes, and are checked in
     //   CcCommon.getIncludeDirsFromIncludesAttribute().
@@ -491,7 +492,11 @@ private void verifyActionIncludePaths(CppCompileAction action, Consumer<String>
     Iterable<PathFragment> includePathsToVerify =
         Iterables.concat(action.getIncludeDirs(), action.getSystemIncludeDirs());
     for (PathFragment includePath : includePathsToVerify) {
-      if (FileSystemUtils.startsWithAny(includePath, ignoredDirs)) {
+      // includePathsToVerify contains all paths that are added as -isystem directive on the command
+      // line, most of which are added for include directives in the CcCompilationContext and are
+      // thus also in ignoredDirs. The hash lookup prevents this from becoming O(N^2) for these.
+      if (ignoredDirs.contains(includePath)
+          || FileSystemUtils.startsWithAny(includePath, ignoredDirs)) {
         continue;
       }
       // One starting ../ is okay for getting to a sibling repository.