Feature configuration: add a field required_variables on flag_sets.
This allows to prevent expansion of flag sets based on whether build variables
are available. If required_variables is not set, and a variable that is
referenced in the flag_set's flags is not available, the build will fail.
We need the new behavior when some input files (for example profile data in
FDO enabled builds) are only available for a subset of the translation units of
a given target.
--
MOS_MIGRATED_REVID=100028996
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CcToolchainFeatures.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CcToolchainFeatures.java
index 67581af..c2d7825 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CcToolchainFeatures.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CcToolchainFeatures.java
@@ -393,10 +393,12 @@
@Immutable
private static class FlagSet implements Serializable {
private final ImmutableSet<String> actions;
+ private final ImmutableSet<String> expandIfAllAvailable;
private final ImmutableList<FlagGroup> flagGroups;
private FlagSet(CToolchain.FlagSet flagSet) throws InvalidConfigurationException {
this.actions = ImmutableSet.copyOf(flagSet.getActionList());
+ this.expandIfAllAvailable = ImmutableSet.copyOf(flagSet.getExpandIfAllAvailableList());
ImmutableList.Builder<FlagGroup> builder = ImmutableList.builder();
for (CToolchain.FlagGroup flagGroup : flagSet.getFlagGroupList()) {
builder.add(new FlagGroup(flagGroup));
@@ -408,6 +410,11 @@
* Adds the flags that apply to the given {@code action} to {@code commandLine}.
*/
private void expandCommandLine(String action, Variables variables, List<String> commandLine) {
+ for (String variable : expandIfAllAvailable) {
+ if (!variables.isAvailable(variable)) {
+ return;
+ }
+ }
if (!actions.contains(action)) {
return;
}
@@ -738,6 +745,13 @@
}
return new NestedView(viewMap, sequenceName, sequenceVariables.get(sequenceName));
}
+
+ /**
+ * Returns whether {@code variable} is set.
+ */
+ private boolean isAvailable(String variable) {
+ return variables.containsKey(variable) || sequenceVariables.containsKey(variable);
+ }
}
/**
diff --git a/src/main/protobuf/crosstool_config.proto b/src/main/protobuf/crosstool_config.proto
index ea3b7ec..6e3ffb2 100644
--- a/src/main/protobuf/crosstool_config.proto
+++ b/src/main/protobuf/crosstool_config.proto
@@ -107,6 +107,16 @@
// If 'with_feature' is omitted, the flag set will be applied
// unconditionally for every action specified.
repeated FeatureSet with_feature = 3;
+
+ // A list of build variables that this feature set needs, but which are
+ // allowed to not be set. If any of the build variables listed is not
+ // set, the feature set will not be expanded.
+ //
+ // NOTE: Consider alternatives before using this; usually tools should
+ // consistently create the same set of files, even if empty; use this
+ // only for backwards compatibility with already existing behavior in tools
+ // that are currently not worth changing.
+ repeated string expand_if_all_available = 4;
}
// Contains all flag specifications for one feature.
