blob: da58df1a6fe74db3ad6dee4df81348ce67688e01 [file] [log] [blame]
// Copyright 2018 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.rules;
import static com.google.devtools.build.lib.packages.Attribute.attr;
import static com.google.devtools.build.lib.packages.BuildType.LABEL;
import static com.google.devtools.build.lib.packages.BuildType.NODEP_LABEL;
import static com.google.devtools.build.lib.packages.RuleClass.Builder.STARLARK_BUILD_SETTING_DEFAULT_ATTR_NAME;
import com.google.devtools.build.lib.analysis.RuleDefinitionEnvironment;
import com.google.devtools.build.lib.analysis.config.BuildConfiguration;
import com.google.devtools.build.lib.cmdline.Label;
import com.google.devtools.build.lib.packages.Attribute.LabelLateBoundDefault;
import com.google.devtools.build.lib.packages.BuildSetting;
import com.google.devtools.build.lib.packages.RuleClass;
import com.google.devtools.build.lib.packages.RuleClass.ToolchainResolutionMode;
import com.google.devtools.build.lib.packages.Type.ConversionException;
import com.google.devtools.build.lib.rules.LateBoundAlias.AbstractAliasRule;
import com.google.devtools.build.lib.skyframe.serialization.autocodec.AutoCodec;
import com.google.devtools.build.lib.skyframe.serialization.autocodec.AutoCodec.VisibleForSerialization;
/**
* Native implementation of label setting and flags.
*
* <p>While most build settings are completely defined in starlark, we're natively defining
* label-typed ones because:
*
* <ul>
* <li>they're essentially special Alias targets
* <li>we don't have a known use case where you'd want to manipulate a label-typed build setting
* in its implementation section.
* </ul>
*
* <p>Once we do have (2), we can consider switching over to starlark implementation. The dangers
* there involve the implementation function returning a label we've never seen before in the build.
* And since label-typed build settings actually return the providers of the targets they point to,
* we'd have to be able to load and configure potentially arbitrary labels on the fly. This is not
* possible today and could easily introduce large performance issues.
*/
public class LabelBuildSettings {
@AutoCodec @VisibleForSerialization
// TODO(b/65746853): find a way to do this without passing the entire BuildConfiguration
static final LabelLateBoundDefault<BuildConfiguration> ACTUAL =
LabelLateBoundDefault.fromTargetConfiguration(
BuildConfiguration.class,
null,
(rule, attributes, configuration) -> {
if (rule == null || configuration == null) {
return attributes.get(STARLARK_BUILD_SETTING_DEFAULT_ATTR_NAME, NODEP_LABEL);
}
Object commandLineValue =
configuration.getOptions().getStarlarkOptions().get(rule.getLabel());
Label asLabel;
try {
asLabel =
commandLineValue == null
? attributes.get(STARLARK_BUILD_SETTING_DEFAULT_ATTR_NAME, NODEP_LABEL)
: LABEL.convert(commandLineValue, "label_flag value resolution");
} catch (ConversionException e) {
throw new IllegalStateException(
"Getting here means we must have processed a transition via"
+ " StarlarkTransition.validate, which checks that LABEL.convert works"
+ " without error.",
e);
}
return asLabel;
});
private static RuleClass buildRuleClass(RuleClass.Builder builder, boolean flag) {
return builder
.removeAttribute("licenses")
.removeAttribute("distribs")
.add(attr(":alias", LABEL).value(ACTUAL))
.setBuildSetting(BuildSetting.create(flag, NODEP_LABEL))
.canHaveAnyProvider()
.useToolchainResolution(ToolchainResolutionMode.DISABLED)
.build();
}
/** Rule definition of label_setting. */
public static final class LabelBuildSettingRule extends AbstractAliasRule {
public LabelBuildSettingRule() {
super("label_setting");
}
@Override
public RuleClass build(RuleClass.Builder builder, RuleDefinitionEnvironment environment) {
return buildRuleClass(builder, /*flag=*/ false);
}
}
/** Rule definition of label_flag */
public static final class LabelBuildFlagRule extends AbstractAliasRule {
public LabelBuildFlagRule() {
super("label_flag");
}
@Override
public RuleClass build(RuleClass.Builder builder, RuleDefinitionEnvironment environment) {
return buildRuleClass(builder, /*flag=*/ true);
}
}
}