Add a undocumented way to define a platform that is autodetected from

the host.

Also add a single instance of that platform for standard usage.

Change-Id: I0e7a8eb3a44099076540c8d955fc0c0c70447583
PiperOrigin-RevId: 153878880

2 files changed, 37 insertions, 0 deletions

diff --git a/src/test/java/com/google/devtools/build/lib/rules/platform/BUILD b/src/test/java/com/google/devtools/build/lib/rules/platform/BUILD
index 82e48b07b6..39b1617172 100644
--- a/src/test/java/com/google/devtools/build/lib/rules/platform/BUILD
+++ b/src/test/java/com/google/devtools/build/lib/rules/platform/BUILD
@@ -10,7 +10,9 @@ java_test(
     test_class = "com.google.devtools.build.lib.AllTests",
     deps = [
         "//src/main/java/com/google/devtools/build/lib:build-base",
+        "//src/main/java/com/google/devtools/build/lib:os_util",
         "//src/main/java/com/google/devtools/build/lib:syntax",
+        "//src/main/java/com/google/devtools/build/lib:util",
         "//src/main/java/com/google/devtools/build/lib/cmdline",
         "//src/main/java/com/google/devtools/build/lib/rules/platform",
         "//src/test/java/com/google/devtools/build/lib:analysis_testutil",
diff --git a/src/test/java/com/google/devtools/build/lib/rules/platform/PlatformTest.java b/src/test/java/com/google/devtools/build/lib/rules/platform/PlatformTest.java
index d07fe4d634..5cb0991dfc 100644
--- a/src/test/java/com/google/devtools/build/lib/rules/platform/PlatformTest.java
+++ b/src/test/java/com/google/devtools/build/lib/rules/platform/PlatformTest.java
@@ -22,6 +22,8 @@ import com.google.devtools.build.lib.analysis.ConfiguredTarget;
 import com.google.devtools.build.lib.analysis.util.BuildViewTestCase;
 import com.google.devtools.build.lib.cmdline.Label;
 import com.google.devtools.build.lib.rules.platform.PlatformInfo.DuplicateConstraintException;
+import com.google.devtools.build.lib.util.CPU;
+import com.google.devtools.build.lib.util.OS;
 import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
@@ -66,6 +68,39 @@ public class PlatformTest extends BuildViewTestCase {
   }
 
   @Test
+  public void testPlatform_host() throws Exception {
+    String currentCpu = CPU.getCurrent().getCanonicalName();
+    String currentOs = OS.getCurrent().getCanonicalName();
+    scratch.file(
+        "host/BUILD",
+        "constraint_setting(name = 'cpu')",
+        "constraint_value(name = '" + currentCpu + "', constraint_setting = ':cpu')",
+        "constraint_value(name = 'another_cpu', constraint_setting = ':cpu')",
+        "constraint_setting(name = 'os')",
+        "constraint_value(name = '" + currentOs + "', constraint_setting = ':os')",
+        "constraint_value(name = 'another_os', constraint_setting = ':os')",
+        "platform(name = 'host_platform',",
+        "    host_platform = True,",
+        "    host_cpu_constraints = [':" + currentCpu + "', ':another_cpu'],",
+        "    host_os_constraints = [':" + currentOs + "', ':another_os'],",
+        ")");
+
+    ConfiguredTarget platform = getConfiguredTarget("//host:host_platform");
+    assertThat(platform).isNotNull();
+
+    PlatformInfo provider = PlatformInfo.fromTarget(platform);
+    assertThat(provider).isNotNull();
+
+    // Check the CPU and OS.
+    ConstraintSettingInfo cpuConstraint = ConstraintSettingInfo.create(makeLabel("//host:cpu"));
+    ConstraintSettingInfo osConstraint = ConstraintSettingInfo.create(makeLabel("//host:os"));
+    assertThat(provider.constraints())
+        .containsExactly(
+            ConstraintValueInfo.create(cpuConstraint, makeLabel("//host:" + currentCpu)),
+            ConstraintValueInfo.create(osConstraint, makeLabel("//host:" + currentOs)));
+  }
+
+  @Test
   public void testPlatform_overlappingConstraintValueError() throws Exception {
     checkError(
         "constraint/overlap",