Modify cc_toolchain_suite rule to allow selection of cc_toolchain label without reading the CROSSTOOL file.

As we want to reroute selecting the toolchain from CROSSTOOL through cc_toolchain, cc_toolchain_suite should have all the necesarry information for obtaining the cc_toolchain label without accessing the CROSSTOOL file.
In order to do that, besides the existing <toolchain.targetCpu>|<toolchain.compiler>, we add <cpu> type of key in 'toolchains' attribute of cc_toolchain_suite.

Now the selection of cc_toolchain label goes as follows:

1. Return toolchains[<cpu>|<compiler> if it exists
2. Return toolchains[<cpu>] if it exists
3. Fall back to the previous state: return toolchains[<toolchain.targetCpu>|<toolchain.compiler>]

RELNOTES: None.
PiperOrigin-RevId: 198588849

2 files changed, 161 insertions, 6 deletions

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 e91ad2214d..e20e3a0d4c 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
@@ -14,10 +14,12 @@
 
 package com.google.devtools.build.lib.rules.cpp;
 
+
 import com.google.common.collect.ImmutableSet;
 import com.google.devtools.build.lib.analysis.RedirectChaser;
 import com.google.devtools.build.lib.analysis.config.BuildConfiguration;
 import com.google.devtools.build.lib.analysis.config.BuildConfiguration.Fragment;
+import com.google.devtools.build.lib.analysis.config.BuildConfiguration.Options;
 import com.google.devtools.build.lib.analysis.config.BuildOptions;
 import com.google.devtools.build.lib.analysis.config.ConfigurationEnvironment;
 import com.google.devtools.build.lib.analysis.config.ConfigurationFragmentFactory;
@@ -34,6 +36,7 @@ import com.google.devtools.build.lib.vfs.FileSystemUtils;
 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 java.util.Map;
 import javax.annotation.Nullable;
 
 /**
@@ -175,13 +178,26 @@ public class CppConfigurationLoader implements ConfigurationFragmentFactory {
     if (crosstoolTop instanceof Rule
         && ((Rule) crosstoolTop).getRuleClass().equals("cc_toolchain_suite")) {
       Rule ccToolchainSuite = (Rule) crosstoolTop;
-      ccToolchainLabel = NonconfigurableAttributeMapper.of(ccToolchainSuite)
-          .get("toolchains", BuildType.LABEL_DICT_UNARY)
-          .get(toolchain.getTargetCpu() + "|" + toolchain.getCompiler());
+
+      String desiredCpu = cpuTransformer.getTransformer().apply(options.get(Options.class).cpu);
+      String key =
+          desiredCpu + (cppOptions.cppCompiler == null ? "" : ("|" + cppOptions.cppCompiler));
+      Map<String, Label> toolchains =
+          NonconfigurableAttributeMapper.of(ccToolchainSuite)
+              .get("toolchains", BuildType.LABEL_DICT_UNARY);
+      ccToolchainLabel = toolchains.get(key);
       if (ccToolchainLabel == null) {
-        throw new InvalidConfigurationException(String.format(
-            "cc_toolchain_suite '%s' does not contain a toolchain for CPU '%s' and compiler '%s'",
-            crosstoolTopLabel, toolchain.getTargetCpu(), toolchain.getCompiler()));
+        ccToolchainLabel = toolchains.get(toolchain.getTargetCpu() + "|" + toolchain.getCompiler());
+      }
+      if (ccToolchainLabel == null) {
+        String errorMessage =
+            String.format(
+                "cc_toolchain_suite '%s' does not contain a toolchain for CPU '%s'",
+                crosstoolTopLabel, toolchain.getTargetCpu());
+        if (cppOptions.cppCompiler != null) {
+          errorMessage = errorMessage + " and compiler " + cppOptions.cppCompiler;
+        }
+        throw new InvalidConfigurationException(errorMessage);
       }
     } else {
       throw new InvalidConfigurationException(String.format(
diff --git a/src/test/java/com/google/devtools/build/lib/rules/cpp/CcToolchainSuiteTest.java b/src/test/java/com/google/devtools/build/lib/rules/cpp/CcToolchainSuiteTest.java
index db890c891e..f6925f2d85 100644
--- a/src/test/java/com/google/devtools/build/lib/rules/cpp/CcToolchainSuiteTest.java
+++ b/src/test/java/com/google/devtools/build/lib/rules/cpp/CcToolchainSuiteTest.java
@@ -15,10 +15,13 @@
 package com.google.devtools.build.lib.rules.cpp;
 
 import static com.google.common.truth.Truth.assertThat;
+import static org.junit.Assert.fail;
 
 import com.google.devtools.build.lib.actions.Action;
 import com.google.devtools.build.lib.actions.Artifact;
 import com.google.devtools.build.lib.actions.util.ActionsTestUtil;
+import com.google.devtools.build.lib.analysis.ConfiguredTarget;
+import com.google.devtools.build.lib.analysis.config.InvalidConfigurationException;
 import com.google.devtools.build.lib.analysis.util.BuildViewTestCase;
 import com.google.devtools.build.lib.collect.nestedset.NestedSet;
 import org.junit.Test;
@@ -241,4 +244,140 @@ public class CcToolchainSuiteTest extends BuildViewTestCase {
     assertThat(ActionsTestUtil.baseArtifactNames(suiteFiles))
         .containsAllOf("k8-marker", "darwin-marker", "windows-marker", "linux-marker");
   }
+
+  @Test
+  public void testCcToolchainLabelFromAttributes() throws Exception {
+    scratch.file(
+        "cc/BUILD",
+        "filegroup(name='empty')",
+        "filegroup(name='everything')",
+        "TOOLCHAIN_NAMES = [",
+        "  'darwin-from-crosstool',",
+        "  'windows-from-crosstool',",
+        "  'k8-compiler',",
+        "  'k8-default-from-cpu',",
+        "  'ppc-compiler',",
+        "  'ppc-default-from-cpu']",
+        "[cc_toolchain(",
+        "    name = NAME,",
+        "    cpu = 'banana',",
+        "    all_files = ':empty',",
+        "    ar_files = ':empty',",
+        "    as_files = ':empty',",
+        "    compiler_files = ':empty',",
+        "    dwp_files = ':empty',",
+        "    linker_files = ':empty',",
+        "    strip_files = ':empty',",
+        "    objcopy_files = ':empty',",
+        "    dynamic_runtime_libs = [':empty'],",
+        "    static_runtime_libs = [':empty'],",
+        ") for NAME in TOOLCHAIN_NAMES]",
+        "cc_toolchain_suite(",
+        "    name = 'suite',",
+        "    toolchains = {",
+        "       'k8|compiler': ':k8-compiler',",
+        "       'ppc': ':invalid-label',",
+        "       'ppc|compiler': ':ppc-compiler',",
+        "       'k8': ':k8-default-from-cpu',",
+        "       'x64_windows' : ':windows-from-crosstool',",
+        "       'darwin' : ':darwin-from-crosstool',",
+        "       'x64_windows|compiler' : ':windows-from-crosstool',",
+        "       'darwin|compiler' : ':darwin-from-crosstool',",
+        "    },",
+        "    proto = \"\"\"",
+        "major_version: 'v1'",
+        "minor_version: '0'",
+        "default_target_cpu: 'k8'",
+        "default_toolchain {",
+        "  cpu: 'k8'",
+        "  toolchain_identifier: 'k8-from-crosstool'",
+        "}",
+        "default_toolchain {",
+        "  cpu: 'ppc'",
+        "  toolchain_identifier: 'ppc-from-crosstool'",
+        "}",
+        "default_toolchain {",
+        "  cpu: 'darwin'",
+        "  toolchain_identifier: 'darwin-from-crosstool'",
+        "}",
+        "default_toolchain {",
+        "  cpu: 'x64_windows'",
+        "  toolchain_identifier: 'windows-from-crosstool'",
+        "}",
+        "toolchain {",
+        "  compiler: 'compiler'",
+        "  target_cpu: 'k8'",
+        "  toolchain_identifier: 'k8-from-crosstool'",
+        "  host_system_name: 'linux'",
+        "  target_system_name: 'linux'",
+        "  abi_version: 'cpu-abi'",
+        "  abi_libc_version: ''",
+        "  target_libc: 'local'",
+        "  builtin_sysroot: 'sysroot'",
+        "  default_grte_top: '//cc:grtetop'",
+        "}",
+        "toolchain {",
+        "  compiler: 'compiler'",
+        "  target_cpu: 'ppc'",
+        "  toolchain_identifier: 'ppc-from-crosstool'",
+        "  host_system_name: 'linux'",
+        "  target_system_name: 'linux'",
+        "  abi_version: 'cpu-abi'",
+        "  abi_libc_version: ''",
+        "  target_libc: 'local'",
+        "  builtin_sysroot: 'sysroot'",
+        "  default_grte_top: '//cc:grtetop'",
+        "}",
+        "toolchain {",
+        "  compiler: 'compiler'",
+        "  target_cpu: 'darwin'",
+        "  toolchain_identifier: 'darwin-from-crosstool'",
+        "  host_system_name: 'linux'",
+        "  target_system_name: 'linux'",
+        "  abi_version: ''",
+        "  abi_libc_version: ''",
+        "  target_libc: ''",
+        "  builtin_sysroot: 'sysroot'",
+        "  default_grte_top: '//cc:grtetop'",
+        "}",
+        "toolchain {",
+        "  compiler: 'compiler'",
+        "  target_cpu: 'x64_windows'",
+        "  toolchain_identifier: 'windows-from-crosstool'",
+        "  host_system_name: 'windows'",
+        "  target_system_name: 'windows'",
+        "  abi_version: ''",
+        "  abi_libc_version: ''",
+        "  target_libc: ''",
+        "  builtin_sysroot: 'sysroot'",
+        "  default_grte_top: '//cc:grtetop'",
+        "}",
+        "\"\"\"",
+        ")");
+
+    scratch.file("a/BUILD", "cc_binary(name='b', srcs=['b.cc'])");
+
+    useConfiguration("--crosstool_top=//cc:suite", "--cpu=k8");
+    ConfiguredTarget c = getConfiguredTarget("//a:b");
+    CppConfiguration config = getConfiguration(c).getFragment(CppConfiguration.class);
+    assertThat(config.getCcToolchainRuleLabel().toString()).isEqualTo("//cc:k8-default-from-cpu");
+
+    useConfiguration("--crosstool_top=//cc:suite", "--compiler=compiler", "--cpu=ppc");
+    config = getConfiguration(getConfiguredTarget("//a:b")).getFragment(CppConfiguration.class);
+    assertThat(config.getCcToolchainRuleLabel().toString()).isEqualTo("//cc:ppc-compiler");
+
+    useConfiguration("--crosstool_top=//cc:suite", "--compiler=compiler", "--cpu=k8");
+    config = getConfiguration(getConfiguredTarget("//a:b")).getFragment(CppConfiguration.class);
+    assertThat(config.getCcToolchainRuleLabel().toString()).isEqualTo("//cc:k8-compiler");
+
+    try {
+      useConfiguration("--crosstool_top=//cc:suite", "--cpu=ppc");
+      getConfiguration(getConfiguredTarget("//a:b")).getFragment(CppConfiguration.class);
+      fail("expected failure because 'ppc' entry points to an invalid label");
+    } catch (InvalidConfigurationException e) {
+      assertThat(e)
+          .hasMessageThat()
+          .contains("The label '//cc:invalid-label' is not a cc_toolchain rule");
+    }
+  }
 }