Support for ThinLTO to be enabled implicitly with AFDO
Allows for ThinLTO to be enabled once the --features=autofdo_implicit_thinlto feature is enabled in the crosstool. Also allows for --features=-thin_lto to override and prevent ThinLTO from being enabled.
RELNOTES: None.
PiperOrigin-RevId: 179687743
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/RuleContext.java b/src/main/java/com/google/devtools/build/lib/analysis/RuleContext.java
index 86339da..b5d0834 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/RuleContext.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/RuleContext.java
@@ -222,24 +222,30 @@
Set<String> globallyEnabled = new HashSet<>();
Set<String> globallyDisabled = new HashSet<>();
parseFeatures(getConfiguration().getDefaultFeatures(), globallyEnabled, globallyDisabled);
- for (ImmutableMap.Entry<Class<? extends Fragment>, Fragment> entry :
- getConfiguration().getAllFragments().entrySet()) {
- if (isLegalFragment(entry.getKey())) {
- globallyEnabled.addAll(entry.getValue().configurationEnabledFeatures(this));
- }
- }
Set<String> packageEnabled = new HashSet<>();
Set<String> packageDisabled = new HashSet<>();
parseFeatures(getRule().getPackage().getFeatures(), packageEnabled, packageDisabled);
+ Set<String> ruleEnabled = new HashSet<>();
+ Set<String> ruleDisabled = new HashSet<>();
+ if (attributes().has("features", Type.STRING_LIST)) {
+ parseFeatures(attributes().get("features", Type.STRING_LIST), ruleEnabled, ruleDisabled);
+ }
+ Set<String> ruleDisabledFeatures =
+ Sets.union(ruleDisabled, Sets.difference(packageDisabled, ruleEnabled));
+ Set<String> disabledFeatures = Sets.union(ruleDisabledFeatures, globallyDisabled);
+ for (ImmutableMap.Entry<Class<? extends Fragment>, Fragment> entry :
+ getConfiguration().getAllFragments().entrySet()) {
+ if (isLegalFragment(entry.getKey())) {
+ globallyEnabled.addAll(
+ entry
+ .getValue()
+ .configurationEnabledFeatures(this, ImmutableSortedSet.copyOf(disabledFeatures)));
+ }
+ }
Set<String> packageFeatures =
Sets.difference(Sets.union(globallyEnabled, packageEnabled), packageDisabled);
- Set<String> ruleFeatures = packageFeatures;
- if (attributes().has("features", Type.STRING_LIST)) {
- Set<String> ruleEnabled = new HashSet<>();
- Set<String> ruleDisabled = new HashSet<>();
- parseFeatures(attributes().get("features", Type.STRING_LIST), ruleEnabled, ruleDisabled);
- ruleFeatures = Sets.difference(Sets.union(packageFeatures, ruleEnabled), ruleDisabled);
- }
+ Set<String> ruleFeatures =
+ Sets.difference(Sets.union(packageFeatures, ruleEnabled), ruleDisabled);
return ImmutableSortedSet.copyOf(Sets.difference(ruleFeatures, globallyDisabled));
}
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/config/BuildConfiguration.java b/src/main/java/com/google/devtools/build/lib/analysis/config/BuildConfiguration.java
index e6e6a36..c3b6c41 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/config/BuildConfiguration.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/config/BuildConfiguration.java
@@ -173,10 +173,9 @@
return ImmutableMap.of();
}
- /**
- * Return set of features enabled by this configuration.
- */
- public ImmutableSet<String> configurationEnabledFeatures(RuleContext ruleContext) {
+ /** Return set of features enabled by this configuration. */
+ public ImmutableSet<String> configurationEnabledFeatures(
+ RuleContext ruleContext, ImmutableSet<String> disabledFeatures) {
return ImmutableSet.of();
}
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppConfiguration.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppConfiguration.java
index 974551f..d843154 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppConfiguration.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppConfiguration.java
@@ -1292,11 +1292,12 @@
}
/**
- * Return set of features enabled by the CppConfiguration, specifically
- * the FDO and LIPO related features enabled by options.
+ * Return set of features enabled by the CppConfiguration, specifically the FDO and LIPO related
+ * features enabled by options.
*/
@Override
- public ImmutableSet<String> configurationEnabledFeatures(RuleContext ruleContext) {
+ public ImmutableSet<String> configurationEnabledFeatures(
+ RuleContext ruleContext, ImmutableSet<String> disabledFeatures) {
ImmutableSet.Builder<String> requestedFeatures = ImmutableSet.builder();
if (cppOptions.getFdoInstrument() != null) {
requestedFeatures.add(CppRuleClasses.FDO_INSTRUMENT);
@@ -1308,6 +1309,11 @@
}
if (isFdo && CppFileTypes.GCC_AUTO_PROFILE.matches(fdoZip)) {
requestedFeatures.add(CppRuleClasses.AUTOFDO);
+ // For LLVM, support implicit enabling of ThinLTO for AFDO unless it has been
+ // explicitly disabled.
+ if (isLLVMCompiler() && !disabledFeatures.contains(CppRuleClasses.THIN_LTO)) {
+ requestedFeatures.add(CppRuleClasses.ENABLE_AFDO_THINLTO);
+ }
}
if (isLipoOptimizationOrInstrumentation()) {
// Map LIPO to ThinLTO for LLVM builds.
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppRuleClasses.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppRuleClasses.java
index ed54a38..af37c28 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppRuleClasses.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppRuleClasses.java
@@ -287,6 +287,16 @@
*/
public static final String THIN_LTO = "thin_lto";
+ /*
+ * A string constant for allowing implicit ThinLTO enablement for AFDO.
+ */
+ public static final java.lang.String AUTOFDO_IMPLICIT_THINLTO = "autofdo_implicit_thinlto";
+
+ /*
+ * A string constant for enabling ThinLTO for AFDO implicitly.
+ */
+ public static final java.lang.String ENABLE_AFDO_THINLTO = "enable_afdo_thinlto";
+
/**
* A string constant for allowing use of shared LTO backend actions for linkstatic tests building
* with ThinLTO.
