Move platform providers to a new package to break cyclic dependencies.

Part of #2219.

Change-Id: I87c7bc9fbfb38d3dbdf193b46247901d0f2a838d
PiperOrigin-RevId: 154719063

13 files changed, 146 insertions, 135 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/BUILD b/src/main/java/com/google/devtools/build/lib/BUILD
index 6e0fb14e40..02086d9fae 100644
--- a/src/main/java/com/google/devtools/build/lib/BUILD
+++ b/src/main/java/com/google/devtools/build/lib/BUILD
@@ -35,6 +35,7 @@ filegroup(
         "//src/main/java/com/google/devtools/build/lib/rules/genquery:srcs",
         "//src/main/java/com/google/devtools/build/lib/rules/genrule:srcs",
         "//src/main/java/com/google/devtools/build/lib/rules/objc:srcs",
+        "//src/main/java/com/google/devtools/build/lib/analysis/platform:srcs",
         "//src/main/java/com/google/devtools/build/lib/rules/platform:srcs",
         "//src/main/java/com/google/devtools/build/lib/sandbox:srcs",
         "//src/main/java/com/google/devtools/build/lib/ssd:srcs",
@@ -1221,6 +1222,7 @@ filegroup(
         "//src/main/java/com/google/devtools/build/lib/rules/genquery:srcs",
         "//src/main/java/com/google/devtools/build/lib/rules/genrule:srcs",
         "//src/main/java/com/google/devtools/build/lib/rules/objc:srcs",
+        "//src/main/java/com/google/devtools/build/lib/analysis/platform:srcs",
         "//src/main/java/com/google/devtools/build/lib/rules/platform:srcs",
     ],
 )
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/platform/BUILD b/src/main/java/com/google/devtools/build/lib/analysis/platform/BUILD
new file mode 100644
index 0000000000..ce3a69d759
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/analysis/platform/BUILD
@@ -0,0 +1,24 @@
+# Description:
+#   Providers defined for platforms, constraints, and toolchains.
+
+package(
+    default_visibility = ["//src:__subpackages__"],
+)
+
+java_library(
+    name = "platform",
+    srcs = glob([
+        "*.java",
+    ]),
+    deps = [
+        "//src/main/java/com/google/devtools/build/lib:packages",
+        "//src/main/java/com/google/devtools/build/lib:skylarkinterface",
+        "//third_party:guava",
+    ],
+)
+
+filegroup(
+    name = "srcs",
+    testonly = 0,  # All srcs should be not test only, overwrite package default.
+    srcs = glob(["**"]),
+)
diff --git a/src/main/java/com/google/devtools/build/lib/rules/platform/ConstraintSettingInfo.java b/src/main/java/com/google/devtools/build/lib/analysis/platform/ConstraintSettingInfo.java
index 3b203e64ca..817580e8fa 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/platform/ConstraintSettingInfo.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/platform/ConstraintSettingInfo.java
@@ -12,12 +12,9 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package com.google.devtools.build.lib.rules.platform;
+package com.google.devtools.build.lib.analysis.platform;
 
-import com.google.common.base.Function;
 import com.google.common.collect.ImmutableMap;
-import com.google.common.collect.Iterables;
-import com.google.devtools.build.lib.analysis.TransitiveInfoCollection;
 import com.google.devtools.build.lib.cmdline.Label;
 import com.google.devtools.build.lib.concurrent.ThreadSafety.Immutable;
 import com.google.devtools.build.lib.packages.ClassObjectConstructor;
@@ -26,7 +23,6 @@ import com.google.devtools.build.lib.packages.SkylarkClassObject;
 import com.google.devtools.build.lib.packages.SkylarkProviderIdentifier;
 import com.google.devtools.build.lib.skylarkinterface.SkylarkModule;
 import com.google.devtools.build.lib.skylarkinterface.SkylarkModuleCategory;
-import com.google.devtools.build.lib.util.Preconditions;
 
 /** Provider for a platform constraint setting that is available to be fulfilled. */
 @SkylarkModule(
@@ -38,10 +34,10 @@ import com.google.devtools.build.lib.util.Preconditions;
 public class ConstraintSettingInfo extends SkylarkClassObject {
 
   /** Name used in Skylark for accessing this provider. */
-  static final String SKYLARK_NAME = "ConstraintSettingInfo";
+  public static final String SKYLARK_NAME = "ConstraintSettingInfo";
 
   /** Skylark constructor and identifier for this provider. */
-  static final ClassObjectConstructor SKYLARK_CONSTRUCTOR =
+  public static final ClassObjectConstructor SKYLARK_CONSTRUCTOR =
       new NativeClassObjectConstructor(SKYLARK_NAME) {};
 
   /** Identifier used to retrieve this provider from rules which export it. */
@@ -60,29 +56,6 @@ public class ConstraintSettingInfo extends SkylarkClassObject {
     return label;
   }
 
-  /** Retrieves and casts the provider from the given target. */
-  public static ConstraintSettingInfo fromTarget(TransitiveInfoCollection target) {
-    Object provider = target.get(SKYLARK_IDENTIFIER);
-    if (provider == null) {
-      return null;
-    }
-    Preconditions.checkState(provider instanceof ConstraintSettingInfo);
-    return (ConstraintSettingInfo) provider;
-  }
-
-  /** Retrieves and casts the providers from the given targets. */
-  public static Iterable<ConstraintSettingInfo> fromTargets(
-      Iterable<? extends TransitiveInfoCollection> targets) {
-    return Iterables.transform(
-        targets,
-        new Function<TransitiveInfoCollection, ConstraintSettingInfo>() {
-          @Override
-          public ConstraintSettingInfo apply(TransitiveInfoCollection target) {
-            return fromTarget(target);
-          }
-        });
-  }
-
   /** Returns a new {@link ConstraintSettingInfo} with the given data. */
   public static ConstraintSettingInfo create(Label constraintSetting) {
     return new ConstraintSettingInfo(constraintSetting);
diff --git a/src/main/java/com/google/devtools/build/lib/rules/platform/ConstraintValueInfo.java b/src/main/java/com/google/devtools/build/lib/analysis/platform/ConstraintValueInfo.java
index 36854ffbfd..9e58126264 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/platform/ConstraintValueInfo.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/platform/ConstraintValueInfo.java
@@ -12,12 +12,9 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package com.google.devtools.build.lib.rules.platform;
+package com.google.devtools.build.lib.analysis.platform;
 
-import com.google.common.base.Function;
 import com.google.common.collect.ImmutableMap;
-import com.google.common.collect.Iterables;
-import com.google.devtools.build.lib.analysis.TransitiveInfoCollection;
 import com.google.devtools.build.lib.cmdline.Label;
 import com.google.devtools.build.lib.concurrent.ThreadSafety.Immutable;
 import com.google.devtools.build.lib.packages.ClassObjectConstructor;
@@ -26,7 +23,6 @@ import com.google.devtools.build.lib.packages.SkylarkClassObject;
 import com.google.devtools.build.lib.packages.SkylarkProviderIdentifier;
 import com.google.devtools.build.lib.skylarkinterface.SkylarkModule;
 import com.google.devtools.build.lib.skylarkinterface.SkylarkModuleCategory;
-import com.google.devtools.build.lib.util.Preconditions;
 
 /** Provider for a platform constraint value that fulfills a {@link ConstraintSettingInfo}. */
 @SkylarkModule(
@@ -38,10 +34,10 @@ import com.google.devtools.build.lib.util.Preconditions;
 public class ConstraintValueInfo extends SkylarkClassObject {
 
   /** Name used in Skylark for accessing this provider. */
-  static final String SKYLARK_NAME = "ConstraintValueInfo";
+  public static final String SKYLARK_NAME = "ConstraintValueInfo";
 
   /** Skylark constructor and identifier for this provider. */
-  static final ClassObjectConstructor SKYLARK_CONSTRUCTOR =
+  public static final ClassObjectConstructor SKYLARK_CONSTRUCTOR =
       new NativeClassObjectConstructor(SKYLARK_NAME) {};
 
   /** Identifier used to retrieve this provider from rules which export it. */
@@ -70,29 +66,6 @@ public class ConstraintValueInfo extends SkylarkClassObject {
     return label;
   }
 
-  /** Retrieves and casts the provider from the given target. */
-  public static ConstraintValueInfo fromTarget(TransitiveInfoCollection target) {
-    Object provider = target.get(SKYLARK_IDENTIFIER);
-    if (provider == null) {
-      return null;
-    }
-    Preconditions.checkState(provider instanceof ConstraintValueInfo);
-    return (ConstraintValueInfo) provider;
-  }
-
-  /** Retrieves and casts the providers from the given targets. */
-  public static Iterable<ConstraintValueInfo> fromTargets(
-      Iterable<? extends TransitiveInfoCollection> targets) {
-    return Iterables.transform(
-        targets,
-        new Function<TransitiveInfoCollection, ConstraintValueInfo>() {
-          @Override
-          public ConstraintValueInfo apply(TransitiveInfoCollection target) {
-            return fromTarget(target);
-          }
-        });
-  }
-
   /** Returns a new {@link ConstraintValueInfo} with the given data. */
   public static ConstraintValueInfo create(ConstraintSettingInfo constraint, Label value) {
     return new ConstraintValueInfo(constraint, value);
diff --git a/src/main/java/com/google/devtools/build/lib/rules/platform/PlatformInfo.java b/src/main/java/com/google/devtools/build/lib/analysis/platform/PlatformInfo.java
index 3f980733cf..64b9262adb 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/platform/PlatformInfo.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/platform/PlatformInfo.java
@@ -12,16 +12,13 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package com.google.devtools.build.lib.rules.platform;
+package com.google.devtools.build.lib.analysis.platform;
 
-import com.google.common.base.Function;
 import com.google.common.collect.ArrayListMultimap;
 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.common.collect.Multimap;
-import com.google.devtools.build.lib.analysis.TransitiveInfoCollection;
 import com.google.devtools.build.lib.concurrent.ThreadSafety.Immutable;
 import com.google.devtools.build.lib.packages.ClassObjectConstructor;
 import com.google.devtools.build.lib.packages.NativeClassObjectConstructor;
@@ -30,7 +27,6 @@ import com.google.devtools.build.lib.packages.SkylarkProviderIdentifier;
 import com.google.devtools.build.lib.skylarkinterface.SkylarkCallable;
 import com.google.devtools.build.lib.skylarkinterface.SkylarkModule;
 import com.google.devtools.build.lib.skylarkinterface.SkylarkModuleCategory;
-import com.google.devtools.build.lib.util.Preconditions;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
@@ -46,10 +42,10 @@ import java.util.Map;
 public class PlatformInfo extends SkylarkClassObject {
 
   /** Name used in Skylark for accessing this provider. */
-  static final String SKYLARK_NAME = "PlatformInfo";
+  public static final String SKYLARK_NAME = "PlatformInfo";
 
   /** Skylark constructor and identifier for this provider. */
-  static final ClassObjectConstructor SKYLARK_CONSTRUCTOR =
+  public static final ClassObjectConstructor SKYLARK_CONSTRUCTOR =
       new NativeClassObjectConstructor(SKYLARK_NAME) {};
 
   /** Identifier used to retrieve this provider from rules which export it. */
@@ -81,29 +77,6 @@ public class PlatformInfo extends SkylarkClassObject {
     return remoteExecutionProperties;
   }
 
-  /** Retrieves and casts the provider from the given target. */
-  public static PlatformInfo fromTarget(TransitiveInfoCollection target) {
-    Object provider = target.get(SKYLARK_IDENTIFIER);
-    if (provider == null) {
-      return null;
-    }
-    Preconditions.checkState(provider instanceof PlatformInfo);
-    return (PlatformInfo) provider;
-  }
-
-  /** Retrieves and casts the providers from the given targets. */
-  public static Iterable<PlatformInfo> fromTargets(
-      Iterable<? extends TransitiveInfoCollection> targets) {
-    return Iterables.transform(
-        targets,
-        new Function<TransitiveInfoCollection, PlatformInfo>() {
-          @Override
-          public PlatformInfo apply(TransitiveInfoCollection target) {
-            return fromTarget(target);
-          }
-        });
-  }
-
   /** Returns a new {@link Builder} for creating a fresh {@link PlatformInfo} instance. */
   public static Builder builder() {
     return new Builder();
diff --git a/src/main/java/com/google/devtools/build/lib/rules/platform/ToolchainInfo.java b/src/main/java/com/google/devtools/build/lib/analysis/platform/ToolchainInfo.java
index 320ee5e9df..1e5e45f462 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/platform/ToolchainInfo.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/platform/ToolchainInfo.java
@@ -12,14 +12,10 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package com.google.devtools.build.lib.rules.platform;
+package com.google.devtools.build.lib.analysis.platform;
 
-import com.google.common.base.Function;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
-import com.google.common.collect.Iterables;
-import com.google.devtools.build.lib.analysis.TransitiveInfoCollection;
-import com.google.devtools.build.lib.analysis.TransitiveInfoProvider;
 import com.google.devtools.build.lib.concurrent.ThreadSafety.Immutable;
 import com.google.devtools.build.lib.events.Location;
 import com.google.devtools.build.lib.packages.ClassObjectConstructor;
@@ -29,7 +25,6 @@ import com.google.devtools.build.lib.packages.SkylarkProviderIdentifier;
 import com.google.devtools.build.lib.skylarkinterface.SkylarkCallable;
 import com.google.devtools.build.lib.skylarkinterface.SkylarkModule;
 import com.google.devtools.build.lib.skylarkinterface.SkylarkModuleCategory;
-import com.google.devtools.build.lib.util.Preconditions;
 import java.util.Map;
 
 /**
@@ -42,17 +37,17 @@ import java.util.Map;
   category = SkylarkModuleCategory.PROVIDER
 )
 @Immutable
-public class ToolchainInfo extends SkylarkClassObject implements TransitiveInfoProvider {
+public class ToolchainInfo extends SkylarkClassObject {
 
   /** Name used in Skylark for accessing this provider. */
-  static final String SKYLARK_NAME = "ToolchainInfo";
+  public static final String SKYLARK_NAME = "ToolchainInfo";
 
   /** Skylark constructor and identifier for this provider. */
-  static final ClassObjectConstructor SKYLARK_CONSTRUCTOR =
+  public static final ClassObjectConstructor SKYLARK_CONSTRUCTOR =
       new NativeClassObjectConstructor(SKYLARK_NAME) {};
 
   /** Identifier used to retrieve this provider from rules which export it. */
-  private static final SkylarkProviderIdentifier SKYLARK_IDENTIFIER =
+  public static final SkylarkProviderIdentifier SKYLARK_IDENTIFIER =
       SkylarkProviderIdentifier.forKey(SKYLARK_CONSTRUCTOR.getKey());
 
   private final ImmutableList<ConstraintValueInfo> execConstraints;
@@ -105,27 +100,4 @@ public class ToolchainInfo extends SkylarkClassObject implements TransitiveInfoP
   public ImmutableList<ConstraintValueInfo> targetConstraints() {
     return targetConstraints;
   }
-
-  /** Retrieves and casts the provider from the given target. */
-  public static ToolchainInfo fromTarget(TransitiveInfoCollection target) {
-    Object provider = target.get(SKYLARK_IDENTIFIER);
-    if (provider == null) {
-      return null;
-    }
-    Preconditions.checkState(provider instanceof ToolchainInfo);
-    return (ToolchainInfo) provider;
-  }
-
-  /** Retrieves and casts the providers from the given targets. */
-  public static Iterable<ToolchainInfo> fromTargets(
-      Iterable<? extends TransitiveInfoCollection> targets) {
-    return Iterables.transform(
-        targets,
-        new Function<TransitiveInfoCollection, ToolchainInfo>() {
-          @Override
-          public ToolchainInfo apply(TransitiveInfoCollection target) {
-            return fromTarget(target);
-          }
-        });
-  }
 }
diff --git a/src/main/java/com/google/devtools/build/lib/rules/platform/BUILD b/src/main/java/com/google/devtools/build/lib/rules/platform/BUILD
index 8b3f0a0d57..c3a8cc5103 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/platform/BUILD
+++ b/src/main/java/com/google/devtools/build/lib/rules/platform/BUILD
@@ -14,6 +14,7 @@ java_library(
         "//src/main/java/com/google/devtools/build/lib:build-base",
         "//src/main/java/com/google/devtools/build/lib:packages",
         "//src/main/java/com/google/devtools/build/lib:skylarkinterface",
+        "//src/main/java/com/google/devtools/build/lib/analysis/platform",
         "//third_party:guava",
     ],
 )
diff --git a/src/main/java/com/google/devtools/build/lib/rules/platform/ConstraintSetting.java b/src/main/java/com/google/devtools/build/lib/rules/platform/ConstraintSetting.java
index 653ea2fe4f..6c903fd04a 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/platform/ConstraintSetting.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/platform/ConstraintSetting.java
@@ -14,13 +14,18 @@
 
 package com.google.devtools.build.lib.rules.platform;
 
+import com.google.common.base.Function;
+import com.google.common.collect.Iterables;
 import com.google.devtools.build.lib.analysis.ConfiguredTarget;
 import com.google.devtools.build.lib.analysis.FileProvider;
 import com.google.devtools.build.lib.analysis.FilesToRunProvider;
 import com.google.devtools.build.lib.analysis.RuleConfiguredTargetBuilder;
 import com.google.devtools.build.lib.analysis.RuleContext;
 import com.google.devtools.build.lib.analysis.RunfilesProvider;
+import com.google.devtools.build.lib.analysis.TransitiveInfoCollection;
+import com.google.devtools.build.lib.analysis.platform.ConstraintSettingInfo;
 import com.google.devtools.build.lib.rules.RuleConfiguredTargetFactory;
+import com.google.devtools.build.lib.util.Preconditions;
 
 /**
  * Defines a category of constraint that can be fulfilled by a constraint_value rule in a platform
@@ -39,4 +44,27 @@ public class ConstraintSetting implements RuleConfiguredTargetFactory {
         .addNativeDeclaredProvider(ConstraintSettingInfo.create(ruleContext.getLabel()))
         .build();
   }
+
+  /** Retrieves and casts the provider from the given target. */
+  public static ConstraintSettingInfo constraintSetting(TransitiveInfoCollection target) {
+    Object provider = target.get(ConstraintSettingInfo.SKYLARK_IDENTIFIER);
+    if (provider == null) {
+      return null;
+    }
+    Preconditions.checkState(provider instanceof ConstraintSettingInfo);
+    return (ConstraintSettingInfo) provider;
+  }
+
+  /** Retrieves and casts the providers from the given targets. */
+  public static Iterable<ConstraintSettingInfo> constraintSettings(
+      Iterable<? extends TransitiveInfoCollection> targets) {
+    return Iterables.transform(
+        targets,
+        new Function<TransitiveInfoCollection, ConstraintSettingInfo>() {
+          @Override
+          public ConstraintSettingInfo apply(TransitiveInfoCollection target) {
+            return constraintSetting(target);
+          }
+        });
+  }
 }
diff --git a/src/main/java/com/google/devtools/build/lib/rules/platform/ConstraintValue.java b/src/main/java/com/google/devtools/build/lib/rules/platform/ConstraintValue.java
index e1aa6d933b..1eb3ba1802 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/platform/ConstraintValue.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/platform/ConstraintValue.java
@@ -14,6 +14,8 @@
 
 package com.google.devtools.build.lib.rules.platform;
 
+import com.google.common.base.Function;
+import com.google.common.collect.Iterables;
 import com.google.devtools.build.lib.analysis.ConfiguredTarget;
 import com.google.devtools.build.lib.analysis.FileProvider;
 import com.google.devtools.build.lib.analysis.FilesToRunProvider;
@@ -21,7 +23,11 @@ import com.google.devtools.build.lib.analysis.RuleConfiguredTarget.Mode;
 import com.google.devtools.build.lib.analysis.RuleConfiguredTargetBuilder;
 import com.google.devtools.build.lib.analysis.RuleContext;
 import com.google.devtools.build.lib.analysis.RunfilesProvider;
+import com.google.devtools.build.lib.analysis.TransitiveInfoCollection;
+import com.google.devtools.build.lib.analysis.platform.ConstraintSettingInfo;
+import com.google.devtools.build.lib.analysis.platform.ConstraintValueInfo;
 import com.google.devtools.build.lib.rules.RuleConfiguredTargetFactory;
+import com.google.devtools.build.lib.util.Preconditions;
 
 /** Defines a potential value of a constraint. */
 public class ConstraintValue implements RuleConfiguredTargetFactory {
@@ -31,7 +37,7 @@ public class ConstraintValue implements RuleConfiguredTargetFactory {
       throws InterruptedException, RuleErrorException {
 
     ConstraintSettingInfo constraint =
-        ConstraintSettingInfo.fromTarget(
+        ConstraintSetting.constraintSetting(
             ruleContext.getPrerequisite(
                 ConstraintValueRule.CONSTRAINT_SETTING_ATTR, Mode.DONT_CHECK));
 
@@ -42,4 +48,27 @@ public class ConstraintValue implements RuleConfiguredTargetFactory {
         .addNativeDeclaredProvider(ConstraintValueInfo.create(constraint, ruleContext.getLabel()))
         .build();
   }
+
+  /** Retrieves and casts the provider from the given target. */
+  public static ConstraintValueInfo constraintValue(TransitiveInfoCollection target) {
+    Object provider = target.get(ConstraintValueInfo.SKYLARK_IDENTIFIER);
+    if (provider == null) {
+      return null;
+    }
+    Preconditions.checkState(provider instanceof ConstraintValueInfo);
+    return (ConstraintValueInfo) provider;
+  }
+
+  /** Retrieves and casts the providers from the given targets. */
+  public static Iterable<ConstraintValueInfo> constraintValues(
+      Iterable<? extends TransitiveInfoCollection> targets) {
+    return Iterables.transform(
+        targets,
+        new Function<TransitiveInfoCollection, ConstraintValueInfo>() {
+          @Override
+          public ConstraintValueInfo apply(TransitiveInfoCollection target) {
+            return constraintValue(target);
+          }
+        });
+  }
 }
diff --git a/src/main/java/com/google/devtools/build/lib/rules/platform/ConstraintValueRule.java b/src/main/java/com/google/devtools/build/lib/rules/platform/ConstraintValueRule.java
index 5593862754..ae8fd0495c 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/platform/ConstraintValueRule.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/platform/ConstraintValueRule.java
@@ -20,6 +20,7 @@ import com.google.common.collect.ImmutableList;
 import com.google.devtools.build.lib.analysis.BaseRuleClasses;
 import com.google.devtools.build.lib.analysis.RuleDefinition;
 import com.google.devtools.build.lib.analysis.RuleDefinitionEnvironment;
+import com.google.devtools.build.lib.analysis.platform.ConstraintSettingInfo;
 import com.google.devtools.build.lib.packages.BuildType;
 import com.google.devtools.build.lib.packages.RuleClass;
 import com.google.devtools.build.lib.syntax.Type;
diff --git a/src/main/java/com/google/devtools/build/lib/rules/platform/Platform.java b/src/main/java/com/google/devtools/build/lib/rules/platform/Platform.java
index d1c48e9445..184f7a8a07 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/platform/Platform.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/platform/Platform.java
@@ -14,6 +14,8 @@
 
 package com.google.devtools.build.lib.rules.platform;
 
+import com.google.common.base.Function;
+import com.google.common.collect.Iterables;
 import com.google.devtools.build.lib.analysis.ConfiguredTarget;
 import com.google.devtools.build.lib.analysis.FileProvider;
 import com.google.devtools.build.lib.analysis.FilesToRunProvider;
@@ -21,11 +23,14 @@ import com.google.devtools.build.lib.analysis.RuleConfiguredTarget.Mode;
 import com.google.devtools.build.lib.analysis.RuleConfiguredTargetBuilder;
 import com.google.devtools.build.lib.analysis.RuleContext;
 import com.google.devtools.build.lib.analysis.RunfilesProvider;
+import com.google.devtools.build.lib.analysis.TransitiveInfoCollection;
+import com.google.devtools.build.lib.analysis.platform.ConstraintValueInfo;
+import com.google.devtools.build.lib.analysis.platform.PlatformInfo;
 import com.google.devtools.build.lib.rules.RuleConfiguredTargetFactory;
-import com.google.devtools.build.lib.rules.platform.PlatformInfo.DuplicateConstraintException;
 import com.google.devtools.build.lib.syntax.Type;
 import com.google.devtools.build.lib.util.CPU;
 import com.google.devtools.build.lib.util.OS;
+import com.google.devtools.build.lib.util.Preconditions;
 import java.util.Map;
 
 /** Defines a platform for execution contexts. */
@@ -41,7 +46,7 @@ public class Platform implements RuleConfiguredTargetFactory {
       autodetectHostConstraints(ruleContext, platformBuilder);
     } else {
       platformBuilder.addConstraints(
-          ConstraintValueInfo.fromTargets(
+          ConstraintValue.constraintValues(
               ruleContext.getPrerequisites(PlatformRule.CONSTRAINT_VALUES_ATTR, Mode.DONT_CHECK)));
     }
 
@@ -52,7 +57,7 @@ public class Platform implements RuleConfiguredTargetFactory {
     PlatformInfo platformInfo;
     try {
       platformInfo = platformBuilder.build();
-    } catch (DuplicateConstraintException e) {
+    } catch (PlatformInfo.DuplicateConstraintException e) {
       // Report the error and return null.
       ruleContext.attributeError(PlatformRule.CONSTRAINT_VALUES_ATTR, e.getMessage());
       return null;
@@ -72,7 +77,7 @@ public class Platform implements RuleConfiguredTargetFactory {
     // Add the CPU.
     CPU cpu = CPU.getCurrent();
     Iterable<ConstraintValueInfo> cpuConstraintValues =
-        ConstraintValueInfo.fromTargets(
+        ConstraintValue.constraintValues(
             ruleContext.getPrerequisites(PlatformRule.HOST_CPU_CONSTRAINTS_ATTR, Mode.DONT_CHECK));
     for (ConstraintValueInfo constraint : cpuConstraintValues) {
       if (cpu.getCanonicalName().equals(constraint.label().getName())) {
@@ -84,7 +89,7 @@ public class Platform implements RuleConfiguredTargetFactory {
     // Add the OS.
     OS os = OS.getCurrent();
     Iterable<ConstraintValueInfo> osConstraintValues =
-        ConstraintValueInfo.fromTargets(
+        ConstraintValue.constraintValues(
             ruleContext.getPrerequisites(PlatformRule.HOST_OS_CONSTRAINTS_ATTR, Mode.DONT_CHECK));
     for (ConstraintValueInfo constraint : osConstraintValues) {
       if (os.getCanonicalName().equals(constraint.label().getName())) {
@@ -93,4 +98,27 @@ public class Platform implements RuleConfiguredTargetFactory {
       }
     }
   }
+
+  /** Retrieves and casts the provider from the given target. */
+  public static PlatformInfo platform(TransitiveInfoCollection target) {
+    Object provider = target.get(PlatformInfo.SKYLARK_IDENTIFIER);
+    if (provider == null) {
+      return null;
+    }
+    Preconditions.checkState(provider instanceof PlatformInfo);
+    return (PlatformInfo) provider;
+  }
+
+  /** Retrieves and casts the providers from the given targets. */
+  public static Iterable<PlatformInfo> platforms(
+      Iterable<? extends TransitiveInfoCollection> targets) {
+    return Iterables.transform(
+        targets,
+        new Function<TransitiveInfoCollection, PlatformInfo>() {
+          @Override
+          public PlatformInfo apply(TransitiveInfoCollection target) {
+            return platform(target);
+          }
+        });
+  }
 }
diff --git a/src/main/java/com/google/devtools/build/lib/rules/platform/PlatformCommon.java b/src/main/java/com/google/devtools/build/lib/rules/platform/PlatformCommon.java
index 3a67979bb8..09d31c15e5 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/platform/PlatformCommon.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/platform/PlatformCommon.java
@@ -16,6 +16,10 @@ package com.google.devtools.build.lib.rules.platform;
 
 import com.google.common.collect.ImmutableMap;
 import com.google.devtools.build.lib.analysis.TransitiveInfoCollection;
+import com.google.devtools.build.lib.analysis.platform.ConstraintSettingInfo;
+import com.google.devtools.build.lib.analysis.platform.ConstraintValueInfo;
+import com.google.devtools.build.lib.analysis.platform.PlatformInfo;
+import com.google.devtools.build.lib.analysis.platform.ToolchainInfo;
 import com.google.devtools.build.lib.events.Location;
 import com.google.devtools.build.lib.packages.ClassObjectConstructor;
 import com.google.devtools.build.lib.skylarkinterface.Param;
@@ -62,11 +66,11 @@ public class PlatformCommon {
   public ClassObjectConstructor getConstraintValueInfoConstructor() {
     return ConstraintValueInfo.SKYLARK_CONSTRUCTOR;
   }
-  
+
   @SkylarkCallable(
-      name = ToolchainInfo.SKYLARK_NAME,
-      doc = "The key used to retrieve the provider containing toolchain data.",
-      structField = true
+    name = ToolchainInfo.SKYLARK_NAME,
+    doc = "The key used to retrieve the provider containing toolchain data.",
+    structField = true
   )
   public ClassObjectConstructor getToolchainInfoConstructor() {
     return ToolchainInfo.SKYLARK_CONSTRUCTOR;
@@ -85,6 +89,7 @@ public class PlatformCommon {
       @Param(
         name = "exec_compatible_with",
         type = SkylarkList.class,
+        generic1 = TransitiveInfoCollection.class,
         defaultValue = "[]",
         named = true,
         positional = false,
@@ -93,6 +98,7 @@ public class PlatformCommon {
       @Param(
         name = "target_compatible_with",
         type = SkylarkList.class,
+        generic1 = TransitiveInfoCollection.class,
         defaultValue = "[]",
         named = true,
         positional = false,
@@ -118,9 +124,9 @@ public class PlatformCommon {
             throws ConversionException, EvalException {
 
           Iterable<ConstraintValueInfo> execConstraints =
-              ConstraintValueInfo.fromTargets(execCompatibleWith);
+              ConstraintValue.constraintValues(execCompatibleWith);
           Iterable<ConstraintValueInfo> targetConstraints =
-              ConstraintValueInfo.fromTargets(targetCompatibleWith);
+              ConstraintValue.constraintValues(targetCompatibleWith);
           ImmutableMap<String, Object> toolchainData =
               ImmutableMap.copyOf(
                   SkylarkDict.castSkylarkDictOrNoneToDict(
diff --git a/src/main/java/com/google/devtools/build/lib/rules/platform/PlatformRule.java b/src/main/java/com/google/devtools/build/lib/rules/platform/PlatformRule.java
index 126cd9d15d..3e4b0f2b9f 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/platform/PlatformRule.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/platform/PlatformRule.java
@@ -20,6 +20,7 @@ import com.google.common.collect.ImmutableList;
 import com.google.devtools.build.lib.analysis.BaseRuleClasses;
 import com.google.devtools.build.lib.analysis.RuleDefinition;
 import com.google.devtools.build.lib.analysis.RuleDefinitionEnvironment;
+import com.google.devtools.build.lib.analysis.platform.ConstraintValueInfo;
 import com.google.devtools.build.lib.packages.BuildType;
 import com.google.devtools.build.lib.packages.RuleClass;
 import com.google.devtools.build.lib.syntax.Type;