Create UnloadedToolchainContexts for exec groups and make exec_group-related toolchains a dependency of their targets. Use a new helper class ToolchainCollection to handle the default/unnamed execution group.
PiperOrigin-RevId: 305695378
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/ToolchainCollection.java b/src/main/java/com/google/devtools/build/lib/analysis/ToolchainCollection.java
new file mode 100644
index 0000000..1f62133
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/analysis/ToolchainCollection.java
@@ -0,0 +1,88 @@
+// Copyright 2020 The Bazel Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+package com.google.devtools.build.lib.analysis;
+
+import com.google.common.base.Preconditions;
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.ImmutableSet;
+import com.google.devtools.build.lib.cmdline.Label;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+
+/**
+ * A wrapper class for a map of exec_group names to their relevent ToolchainContext.
+ *
+ * @param <T> any class that extends ToolchainCollection so this can be used, e.g., both before and
+ * after toolchain resolution.
+ */
+public class ToolchainCollection<T extends ToolchainContext> {
+ private static final String DEFAULT_EXEC_GROUP_NAME = "default_exec_group";
+
+ /** A map of execution group names to toolchain contexts. */
+ private final ImmutableMap<String, T> toolchainContexts;
+
+ private ToolchainCollection(Map<String, T> contexts) {
+ Preconditions.checkArgument(contexts.containsKey(DEFAULT_EXEC_GROUP_NAME));
+ toolchainContexts = ImmutableMap.copyOf(contexts);
+ }
+
+ /** Builder for ToolchainCollection. */
+ public static class Builder<T extends ToolchainContext> {
+ private final Map<String, T> toolchainContexts = new HashMap<>();
+
+ public ToolchainCollection<T> build() {
+ return new ToolchainCollection<>(toolchainContexts);
+ }
+
+ public void addContext(String execGroup, T context) {
+ Preconditions.checkArgument(
+ !toolchainContexts.containsKey(execGroup),
+ "Duplicate add of '%s' exec group to toolchain collection.",
+ execGroup);
+ toolchainContexts.put(execGroup, context);
+ }
+
+ public Builder<T> addDefaultContext(T context) {
+ addContext(DEFAULT_EXEC_GROUP_NAME, context);
+ return this;
+ }
+ }
+
+ public T getDefaultToolchainContext() {
+ return toolchainContexts.get(DEFAULT_EXEC_GROUP_NAME);
+ }
+
+ public T getToolchainContext(String execGroup) {
+ return toolchainContexts.get(execGroup);
+ }
+
+ public ImmutableSet<Label> getRequiredToolchains() {
+ Set<Label> requiredToolchains = new HashSet<>();
+ for (T context : toolchainContexts.values()) {
+ requiredToolchains.addAll(context.resolvedToolchainLabels());
+ }
+ return ImmutableSet.copyOf(requiredToolchains);
+ }
+
+ public ToolchainCollection<ToolchainContext> asToolchainContexts() {
+ return new ToolchainCollection<>(ImmutableMap.copyOf(toolchainContexts));
+ }
+
+ public Collection<T> getContexts() {
+ return toolchainContexts.values();
+ }
+}
