Introduce shorten_virtual_includes cc toolchain feature

Fixes bazelbuild#18683

Related: protocolbuffers/protobuf#20085

This change is a rework of bazelbuild#26005 to enable short virtual includes based on a cc feature, therefore we can limit the change to only MSVC compiler on Windows.

RELNOTES: If a cc toolchain feature named `shorten_virtual_includes` is enabled, virtual include header files are linked under `bin/_virtual_includes/<hash of target path>` instead of `bin/<target package path>/_virtual_includes/<target name>`. This shortens the virtual include paths which is critical for mitigating long path issue with MSVC on Windows.

Closes bazelbuild#26528.

PiperOrigin-RevId: 781975309
Change-Id: Ia573a5f25707ad2462aa3a4459fc66db1779df36

Author: meteorcloudy

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

@@ -387,6 +387,12 @@ public static ToolchainTypeRequirement ccToolchainTypeRequirement(RuleDefinition
   /** A string constant for a feature that, if enabled, disables .d file handling. */
   public static final String NO_DOTD_FILE = "no_dotd_file";
 
+  /**
+   * A string constant for a feature that, if enabled, shortens the virtual include paths via
+   * hashing.
+   */
+  public static final String SHORTEN_VIRTUAL_INCLUDES = "shorten_virtual_includes";
+
   /*
    * A string constant for the fdo_instrument feature.
    */

src/main/starlark/builtins_bzl/common/cc/cc_compilation_helper.bzl

@@ -59,7 +59,8 @@ def _compute_public_headers(
         label,
         binfiles_dir,
         non_module_map_headers,
-        is_sibling_repository_layout):
+        is_sibling_repository_layout,
+        shorten_virtual_includes):
     if include_prefix:
         if not paths.is_normalized(include_prefix, False):
             fail("include prefix should not contain uplevel references: " + include_prefix)
@@ -111,7 +112,11 @@ def _compute_public_headers(
 
     module_map_headers = []
     virtual_to_original_headers_list = []
-    virtual_include_dir = paths.join(paths.join(package_source_root(label.workspace_name, label.package, is_sibling_repository_layout), _VIRTUAL_INCLUDES_DIR), label.name)
+    source_package_path = package_source_root(label.workspace_name, label.package, is_sibling_repository_layout)
+    if shorten_virtual_includes:
+        virtual_include_dir = paths.join(_VIRTUAL_INCLUDES_DIR, "%x" % hash(paths.join(source_package_path, label.name)))
+    else:
+        virtual_include_dir = paths.join(source_package_path, _VIRTUAL_INCLUDES_DIR, label.name)
     for original_header in public_headers_artifacts:
         repo_relative_path = _repo_relative_path(original_header)
         if not repo_relative_path.startswith(strip_prefix):
@@ -228,6 +233,7 @@ def _init_cc_compilation_context(
     bin_include_dir = _include_dir(binfiles_dir, repo_path, sibling_repo_layout)
     quote_include_dirs_for_context = [repo_path, gen_include_dir, bin_include_dir] + quote_include_dirs
     external = repo_name != "" and _enabled(feature_configuration, "external_include_paths")
+    shorten_virtual_includes = _enabled(feature_configuration, "shorten_virtual_includes")
     external_include_dirs = []
     declared_include_srcs = []
 
@@ -256,6 +262,7 @@ def _init_cc_compilation_context(
         binfiles_dir,
         non_module_map_headers,
         sibling_repo_layout,
+        shorten_virtual_includes,
     )
     if public_headers.virtual_include_path:
         if external:
@@ -293,6 +300,7 @@ def _init_cc_compilation_context(
         binfiles_dir,
         non_module_map_headers,
         sibling_repo_layout,
+        shorten_virtual_includes,
     )
 
     separate_module = None

src/test/java/com/google/devtools/build/lib/analysis/mock/cc_toolchain_config.bzl

@@ -122,6 +122,7 @@ _FEATURE_NAMES = struct(
     cpp_compile_with_requirements = "cpp_compile_with_requirements",
     no_copts_tokenization = "no_copts_tokenization",
     generate_linkmap = "generate_linkmap",
+    shorten_virtual_includes = "shorten_virtual_includes",
 )
 
 _cpp_modules_feature = feature(
@@ -142,6 +143,11 @@ _supports_dynamic_linker_feature = feature(
     enabled = True,
 )
 
+_shorten_virtual_includes_feature = feature(
+    name = _FEATURE_NAMES.shorten_virtual_includes,
+    enabled = True,
+)
+
 _supports_interface_shared_libraries_feature = feature(
     name = _FEATURE_NAMES.supports_interface_shared_libraries,
     enabled = True,
@@ -1451,6 +1457,7 @@ _feature_name_to_feature = {
     _FEATURE_NAMES.cpp_compile_with_requirements: _cpp_compile_with_requirements,
     _FEATURE_NAMES.generate_pdb_file: _generate_pdb_file_feature,
     _FEATURE_NAMES.generate_linkmap: _generate_linkmap_feature,
+    _FEATURE_NAMES.shorten_virtual_includes: _shorten_virtual_includes_feature,
     "header_modules_feature_configuration": _header_modules_feature_configuration,
     "env_var_feature_configuration": _env_var_feature_configuration,
     "host_and_nonhost_configuration": _host_and_nonhost_configuration,

src/test/java/com/google/devtools/build/lib/rules/cpp/CcCommonTest.java

@@ -1079,6 +1079,37 @@ public void testIncludeManglingSmoke() throws Exception {
                 .getRelative("third_party/a/_virtual_includes/a"));
   }
 
+  @Test
+  public void testIncludeManglingSmokeWithShortendVirtualIncludes() throws Exception {
+    getAnalysisMock()
+        .ccSupport()
+        .setupCcToolchainConfig(
+            mockToolsConfig,
+            CcToolchainConfig.builder().withFeatures(CppRuleClasses.SHORTEN_VIRTUAL_INCLUDES));
+    scratch.file(
+        "third_party/a/BUILD",
+        """
+        licenses(["notice"])
+
+        cc_library(
+            name = "a",
+            hdrs = ["v1/b/c.h"],
+            include_prefix = "lib",
+            strip_include_prefix = "v1",
+        )
+        """);
+
+    ConfiguredTarget lib = getConfiguredTarget("//third_party/a");
+    CcCompilationContext ccCompilationContext = lib.get(CcInfo.PROVIDER).getCcCompilationContext();
+    assertThat(ActionsTestUtil.prettyArtifactNames(ccCompilationContext.getDeclaredIncludeSrcs()))
+        .containsExactly("_virtual_includes/207132b2/lib/b/c.h", "third_party/a/v1/b/c.h");
+    assertThat(ccCompilationContext.getIncludeDirs())
+        .containsExactly(
+            getTargetConfiguration()
+                .getBinFragment(RepositoryName.MAIN)
+                .getRelative("_virtual_includes/207132b2"));
+  }
+
   @Test
   public void testUpLevelReferencesInIncludeMangling() throws Exception {
     scratch.file(