Extract --sysroot flag from bazel and move it into crosstool

This is an encore of https://github.com/bazelbuild/bazel/commit/6127358c1799d8d83cebbd499edac89f869df41b .

RELNOTES: None.
PiperOrigin-RevId: 152803621

7 files changed, 135 insertions, 48 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/rules/apple/cpp/AppleCcToolchain.java b/src/main/java/com/google/devtools/build/lib/rules/apple/cpp/AppleCcToolchain.java
index 92902bcac7..de55d33b12 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/apple/cpp/AppleCcToolchain.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/apple/cpp/AppleCcToolchain.java
@@ -53,7 +53,7 @@ public class AppleCcToolchain extends CcToolchain {
   public static final String APPLE_SDK_PLATFORM_VALUE_KEY = "apple_sdk_platform_value";
 
   @Override
-  protected Map<String, String> getBuildVariables(RuleContext ruleContext)
+  protected Map<String, String> getLocalBuildVariables(RuleContext ruleContext)
       throws RuleErrorException {
     AppleConfiguration appleConfiguration = ruleContext.getFragment(AppleConfiguration.class);
 
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 9cb154f3db..3d5c9223ca 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
@@ -354,14 +354,33 @@ public class CcToolchain implements RuleConfiguredTargetFactory {
   }
 
   /**
-   * Returns a map that should be templated into the crosstool as build variables. Is meant to
-   * be overridden by subclasses of CcToolchain.
+   * Returns a map that should be templated into the crosstool as build variables
    *
    * @param ruleContext the rule context
    * @throws RuleErrorException if there are configuration errors making it impossible to resolve
    *     certain build variables of this toolchain
    */
-  protected Map<String, String> getBuildVariables(RuleContext ruleContext)
+  protected final Map<String, String> getBuildVariables(RuleContext ruleContext)
+      throws RuleErrorException {
+    CppConfiguration cppConfiguration = ruleContext.getFragment(CppConfiguration.class);
+    ImmutableMap.Builder<String, String> variables = ImmutableMap.builder();
+    if (cppConfiguration.getSysroot() != null) {
+      variables.put(
+          CppRuleClasses.SYSROOT_VARIABLE, cppConfiguration.getSysroot().getSafePathString());
+    }
+    variables.putAll(getLocalBuildVariables(ruleContext));
+    return variables.build();
+  }
+
+  /**
+   * Returns a map that should be templated into the crosstool as build variables. Is meant to be
+   * overridden by subclasses of CcToolchain.
+   *
+   * @param ruleContext the rule context
+   * @throws RuleErrorException if there are configuration errors making it impossible to resolve
+   *     certain build variables of this toolchain
+   */
+  protected Map<String, String> getLocalBuildVariables(RuleContext ruleContext)
       throws RuleErrorException {
     return ImmutableMap.<String, String>of();
   }
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppActionConfigs.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppActionConfigs.java
index ae53fc1d46..c70e3f34e6 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppActionConfigs.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppActionConfigs.java
@@ -58,6 +58,20 @@ public class CppActionConfigs {
         .join(
             ImmutableList.of(
                 "action_config {",
+                "   config_name: 'assemble'",
+                "   action_name: 'assemble'",
+                "   tool {",
+                "       tool_path: '" + gccToolPath + "'",
+                "   }",
+                "}",
+                "action_config {",
+                "   config_name: 'preprocess-assemble'",
+                "   action_name: 'preprocess-assemble'",
+                "   tool {",
+                "       tool_path: '" + gccToolPath + "'",
+                "   }",
+                "}",
+                "action_config {",
                 "   config_name: 'c-compile'",
                 "   action_name: 'c-compile'",
                 "   tool {",
@@ -72,6 +86,34 @@ public class CppActionConfigs {
                 "   }",
                 "}",
                 "action_config {",
+                "   config_name: 'c++-header-parsing'",
+                "   action_name: 'c++-header-parsing'",
+                "   tool {",
+                "       tool_path: '" + gccToolPath + "'",
+                "   }",
+                "}",
+                "action_config {",
+                "   config_name: 'c++-header-preprocessing'",
+                "   action_name: 'c++-header-preprocessing'",
+                "   tool {",
+                "       tool_path: '" + gccToolPath + "'",
+                "   }",
+                "}",
+                "action_config {",
+                "  config_name: 'c++-module-compile'",
+                "  action_name: 'c++-module-compile'",
+                "  tool {",
+                "    tool_path: '" + gccToolPath + "'",
+                "  }",
+                "}",
+                "action_config {",
+                "  config_name: 'c++-module-codegen'",
+                "  action_name: 'c++-module-codegen'",
+                "  tool {",
+                "    tool_path: '" + gccToolPath + "'",
+                "  }",
+                "}",
+                "action_config {",
                 "   config_name: 'c++-link-executable'",
                 "   action_name: 'c++-link-executable'",
                 "   tool {",
@@ -243,6 +285,21 @@ public class CppActionConfigs {
                 "   }",
                 "}",
                 "feature {",
+                "  name: 'preprocessor_defines'",
+                "  flag_set {",
+                "    action: 'preprocess-assemble'",
+                "    action: 'c-compile'",
+                "    action: 'c++-compile'",
+                "    action: 'c++-header-parsing'",
+                "    action: 'c++-header-preprocessing'",
+                "    action: 'c++-module-compile'",
+                "    action: 'clif-match'",
+                "    flag_group {",
+                "      flag: '-D%{preprocessor_defines}'",
+                "    }",
+                "  }",
+                "}",
+                "feature {",
                 "   name: 'runtime_library_search_directories',",
                 "   flag_set {",
                 "       expand_if_all_available: 'runtime_library_search_directories'",
@@ -467,6 +524,28 @@ public class CppActionConfigs {
                 "   }",
                 "}",
                 "feature {",
+                "    name: 'sysroot'",
+                "    enabled: true,",
+                "    flag_set {",
+                "        action: 'assemble'",
+                "        action: 'preprocess-assemble'",
+                "        action: 'c++-header-parsing'",
+                "        action: 'c++-header-preprocessing'",
+                "        action: 'c-compile'",
+                "        action: 'c++-compile'",
+                "        action: 'c++-module-compile'",
+                "        action: 'c++-module-codegen'",
+                "        action: 'clif-match'",
+                "        action: 'c++-link-interface-dynamic-library'",
+                "        action: 'c++-link-dynamic-library'",
+                "        action: 'c++-link-executable'",
+                "        expand_if_all_available: 'sysroot'",
+                "        flag_group {",
+                "            flag: '--sysroot=%{sysroot}'",
+                "        }",
+                "    }",
+                "}",
+                "feature {",
                 "   name: 'fission_support'",
                 "   flag_set {",
                 "       action: 'c++-link-executable'",
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 54e8d6457c..03dd461e53 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
@@ -632,31 +632,17 @@ public class CppConfiguration extends BuildConfiguration.Fragment {
     // and libc versions, you must always choose compatible ones.
     runtimeSysroot = defaultSysroot;
 
-    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(),
-        convertOptionalOptions(toolchain.getOptionalUnfilteredCxxFlagList()),
-        ImmutableList.<String>of());
+    unfilteredCompilerFlags =
+        new FlagList(
+            ImmutableList.copyOf(toolchain.getUnfilteredCxxFlagList()),
+            convertOptionalOptions(toolchain.getOptionalUnfilteredCxxFlagList()),
+            ImmutableList.<String>of());
 
     ImmutableList.Builder<String> linkoptsBuilder = ImmutableList.builder();
     linkoptsBuilder.addAll(cppOptions.linkoptList);
     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();
@@ -718,10 +704,14 @@ public class CppConfiguration extends BuildConfiguration.Fragment {
     for (CrosstoolConfig.MakeVariable variable : toolchain.getMakeVariableList()) {
       makeVariablesBuilder.put(variable.getName(), variable.getValue());
     }
-    if (sysrootFlag != null) {
+    // TODO(b/36544671): Remove after crosstools have been updated to add sysroot to CC_FLAGS
+    if (sysroot != null) {
       String ccFlags = makeVariablesBuilder.get("CC_FLAGS");
-      ccFlags = ccFlags.isEmpty() ? sysrootFlag : ccFlags + " " + sysrootFlag;
-      makeVariablesBuilder.put("CC_FLAGS", ccFlags);
+      if (!ccFlags.contains(sysroot.getSafePathString())) {
+        String sysrootFlag = "--sysroot=" + sysroot.getSafePathString();
+        ccFlags = ccFlags.isEmpty() ? sysrootFlag : ccFlags + " " + sysrootFlag;
+        makeVariablesBuilder.put("CC_FLAGS", ccFlags);
+      }
     }
     this.additionalMakeVariables = ImmutableMap.copyOf(makeVariablesBuilder);
   }
@@ -740,7 +730,7 @@ public class CppConfiguration extends BuildConfiguration.Fragment {
 
     return result.build();
   }
-  
+
   private static boolean actionsAreConfigured(CToolchain toolchain) {
     return Iterables.any(
         toolchain.getActionConfigList(),
@@ -915,26 +905,6 @@ public class CppConfiguration extends BuildConfiguration.Fragment {
               toolchainBuilder);
         }
 
-        if (!features.contains("preprocessor_defines")) {
-          TextFormat.merge(
-              ""
-                  + "feature {"
-                  + "  name: 'preprocessor_defines'"
-                  + "  flag_set {"
-                  + "    action: 'preprocess-assemble'"
-                  + "    action: 'c-compile'"
-                  + "    action: 'c++-compile'"
-                  + "    action: 'c++-header-parsing'"
-                  + "    action: 'c++-header-preprocessing'"
-                  + "    action: 'c++-module-compile'"
-                  + "    action: 'clif-match'"
-                  + "    flag_group {"
-                  + "      flag: '-D%{preprocessor_defines}'"
-                  + "    }"
-                  + "  }"
-                  + "}",
-              toolchainBuilder);
-        }
         if (!features.contains("include_paths")) {
           TextFormat.merge(
               ""
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppRuleClasses.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppRuleClasses.java
index 698353a105..5d78885f5a 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppRuleClasses.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppRuleClasses.java
@@ -310,4 +310,7 @@ public class CppRuleClasses {
 
   /** A string constant for the match-clif feature. */
   public static final String MATCH_CLIF = "match_clif";
+
+  /** A build variable for the location of the sysroot (relative to the exec path or absolute) */
+  public static final String SYSROOT_VARIABLE = "sysroot";
 }
diff --git a/src/test/java/com/google/devtools/build/lib/rules/cpp/CrosstoolConfigurationLoaderTest.java b/src/test/java/com/google/devtools/build/lib/rules/cpp/CrosstoolConfigurationLoaderTest.java
index 30b5af1d95..cff877e2f0 100644
--- a/src/test/java/com/google/devtools/build/lib/rules/cpp/CrosstoolConfigurationLoaderTest.java
+++ b/src/test/java/com/google/devtools/build/lib/rules/cpp/CrosstoolConfigurationLoaderTest.java
@@ -514,7 +514,7 @@ public class CrosstoolConfigurationLoaderTest extends AnalysisTestCase {
             "cxx-flag-A-1", "cxx-flag-A-2", "cxx-fastbuild-flag-A-1", "cxx-fastbuild-flag-A-2"),
         toolchainA.getCxxOptions(NO_FEATURES));
     assertEquals(
-        Arrays.asList("--sysroot=some", "unfiltered-flag-A-1", "unfiltered-flag-A-2"),
+        Arrays.asList("unfiltered-flag-A-1", "unfiltered-flag-A-2"),
         toolchainA.getUnfilteredCompilerOptions(NO_FEATURES));
     assertEquals(
         Arrays.asList(
diff --git a/src/test/java/com/google/devtools/build/lib/rules/cpp/LinkBuildVariablesTest.java b/src/test/java/com/google/devtools/build/lib/rules/cpp/LinkBuildVariablesTest.java
index 004347cdc9..bb2c774704 100644
--- a/src/test/java/com/google/devtools/build/lib/rules/cpp/LinkBuildVariablesTest.java
+++ b/src/test/java/com/google/devtools/build/lib/rules/cpp/LinkBuildVariablesTest.java
@@ -293,6 +293,22 @@ public class LinkBuildVariablesTest extends BuildViewTestCase {
   }
 
   @Test
+  public void testSysrootVariable() throws Exception {
+    AnalysisMock.get()
+        .ccSupport()
+        .setupCrosstool(mockToolsConfig, "builtin_sysroot: '/usr/local/custom-sysroot'");
+    useConfiguration();
+
+    scratch.file("x/BUILD", "cc_binary(name = 'foo', srcs = ['a.cc'])");
+    scratch.file("x/a.cc");
+
+    ConfiguredTarget testTarget = getConfiguredTarget("//x:foo");
+    Variables testVariables = getLinkBuildVariables(testTarget, LinkTargetType.EXECUTABLE);
+
+    assertThat(testVariables.isAvailable(CppRuleClasses.SYSROOT_VARIABLE)).isTrue();
+  }
+
+  @Test
   public void testIsUsingFissionVariable() throws Exception {
     scratch.file("x/BUILD",
         "cc_binary(name = 'foo', srcs = ['foo.cc'])");