Allow --toolchain_resolution_debug to match specific targets, as well as specific toolchain types.

This will create more skyframe nodes and edges, but only when the `--toolchain_resolution_debug` flag is set, and so should not have any effect on memory usage during normal non-debugging operation.

RELNOTES: The `--toolchain_resolution_debug` flag now accepts regexes matching targets, as well as toolchain types, when choosing what debug messages to print.
PiperOrigin-RevId: 394077188

Author: katre

src/main/java/com/google/devtools/build/lib/analysis/PlatformConfiguration.java

@@ -115,22 +115,25 @@ public List<Label> getAdditionalExecutionConstraintsFor(Label label) {
     return constraints.build();
   }
 
-  /** Returns true if toolchain resolution debug info should be printed for this toolchain type. */
-  public boolean debugToolchainResolution(Label toolchainType) {
-    return debugToolchainResolution(ImmutableList.of(toolchainType));
+  /**
+   * Returns true if toolchain resolution debug info should be printed for this label, which could
+   * be a toolchain type or a specific target.
+   */
+  public boolean debugToolchainResolution(Label label) {
+    return debugToolchainResolution(ImmutableList.of(label));
   }
 
   /**
-   * Returns true if toolchain resolution debug info should be printed for any of these toolchain
-   * types.
+   * Returns true if toolchain resolution debug info should be printed for any of these labels,
+   * which could be either toolchain types or specific targets.
    */
-  public boolean debugToolchainResolution(Collection<Label> toolchainTypes) {
-    if (toolchainTypes.isEmpty()) {
+  public boolean debugToolchainResolution(Collection<Label> labels) {
+    if (labels.isEmpty()) {
       // Check an empty string, in case the filter is .*
       return this.toolchainResolutionDebugRegexFilter.test("");
     }
-    return toolchainTypes.stream()
+    return labels.stream()
         .map(Label::getCanonicalForm)
-        .anyMatch(toolchainType -> this.toolchainResolutionDebugRegexFilter.test(toolchainType));
+        .anyMatch(this.toolchainResolutionDebugRegexFilter);
   }
 }

src/main/java/com/google/devtools/build/lib/analysis/PlatformOptions.java

@@ -154,10 +154,10 @@ public class PlatformOptions extends FragmentOptions {
       effectTags = {OptionEffectTag.TERMINAL_OUTPUT},
       help =
           "Print debug information during toolchain resolution. The flag takes a regex, which is"
-              + " checked against toolchain types to see which to debug. Multiple regexes may be"
-              + " separated by commas, and then each regex is checked separately. Note: The output"
-              + " of this flag is very complex and will likely only be useful to experts in"
-              + " toolchain resolution.")
+              + " checked against toolchain types and specific targets to see which to debug. "
+              + "Multiple regexes may be  separated by commas, and then each regex is checked "
+              + "separately. Note: The output of this flag is very complex and will likely only be "
+              + "useful to experts in toolchain resolution.")
   public RegexFilter toolchainResolutionDebug;
 
   @Option(

src/main/java/com/google/devtools/build/lib/query2/cquery/ConfiguredTargetAccessor.java

@@ -217,6 +217,9 @@ private static ToolchainCollection<ToolchainContext> getToolchainContexts(
     ImmutableSet<Label> execConstraintLabels =
         getExecutionPlatformConstraints(rule, config.getFragment(PlatformConfiguration.class));
     ImmutableMap<String, ExecGroup> execGroups = rule.getRuleClassObject().getExecGroups();
+    // Check if this specific target should be debugged for toolchain resolution.
+    boolean debugTarget =
+        config.getFragment(PlatformConfiguration.class).debugToolchainResolution(target.getLabel());
 
     ToolchainCollection.Builder<UnloadedToolchainContext> toolchainContexts =
         ToolchainCollection.builder();
@@ -231,6 +234,7 @@ private static ToolchainCollection<ToolchainContext> getToolchainContexts(
                         .configurationKey(configurationKey)
                         .requiredToolchainTypeLabels(execGroup.requiredToolchains())
                         .execConstraintLabels(execGroup.execCompatibleWith())
+                        .debugTarget(debugTarget)
                         .build());
         if (context == null) {
           return null;
@@ -244,6 +248,7 @@ private static ToolchainCollection<ToolchainContext> getToolchainContexts(
                       .configurationKey(configurationKey)
                       .requiredToolchainTypeLabels(requiredToolchains)
                       .execConstraintLabels(execConstraintLabels)
+                      .debugTarget(debugTarget)
                       .build());
       if (defaultContext == null) {
         return null;

src/main/java/com/google/devtools/build/lib/skyframe/ConfiguredTargetFunction.java

@@ -528,11 +528,18 @@ public static ComputedToolchainContexts computeUnloadedToolchainContexts(
     Map<String, ToolchainContextKey> toolchainContextKeys = new HashMap<>();
     String targetUnloadedToolchainContext = "target-unloaded-toolchain-context";
 
+    // Check if this specific target should be debugged for toolchain resolution.
+    boolean debugTarget =
+        configuration
+            .getFragment(PlatformConfiguration.class)
+            .debugToolchainResolution(targetAndConfig.getLabel());
+
     ToolchainContextKey.Builder toolchainContextKeyBuilder =
         ToolchainContextKey.key()
             .configurationKey(toolchainConfig)
             .requiredToolchainTypeLabels(requiredDefaultToolchains)
-            .execConstraintLabels(defaultExecConstraintLabels);
+            .execConstraintLabels(defaultExecConstraintLabels)
+            .debugTarget(debugTarget);
 
     if (parentToolchainContextKey != null) {
       // Find out what execution platform the parent used, and force that.
@@ -560,6 +567,7 @@ public static ComputedToolchainContexts computeUnloadedToolchainContexts(
               .configurationKey(toolchainConfig)
               .requiredToolchainTypeLabels(execGroup.requiredToolchains())
               .execConstraintLabels(execGroup.execCompatibleWith())
+              .debugTarget(debugTarget)
               .build());
     }
 

src/main/java/com/google/devtools/build/lib/skyframe/SingleToolchainResolutionFunction.java

@@ -79,11 +79,14 @@ public SkyValue compute(SkyKey skyKey, Environment env)
       throw new ToolchainResolutionFunctionException(e);
     }
 
-    // Find the right one.
+    // Check if we are debugging the target or the toolchain type.
     boolean debug =
-        configuration
-            .getFragment(PlatformConfiguration.class)
-            .debugToolchainResolution(key.toolchainTypeLabel());
+        key.debugTarget()
+            || configuration
+                .getFragment(PlatformConfiguration.class)
+                .debugToolchainResolution(key.toolchainTypeLabel());
+
+    // Find the right one.
     return resolveConstraints(
         key.toolchainTypeLabel(),
         key.availableExecutionPlatformKeys(),

src/main/java/com/google/devtools/build/lib/skyframe/SingleToolchainResolutionValue.java

@@ -39,8 +39,26 @@ public static SingleToolchainResolutionKey key(
       Label toolchainTypeLabel,
       ConfiguredTargetKey targetPlatformKey,
       List<ConfiguredTargetKey> availableExecutionPlatformKeys) {
+    return key(
+        configurationKey,
+        toolchainTypeLabel,
+        targetPlatformKey,
+        availableExecutionPlatformKeys,
+        false);
+  }
+
+  public static SingleToolchainResolutionKey key(
+      BuildConfigurationValue.Key configurationKey,
+      Label toolchainTypeLabel,
+      ConfiguredTargetKey targetPlatformKey,
+      List<ConfiguredTargetKey> availableExecutionPlatformKeys,
+      boolean debugTarget) {
     return SingleToolchainResolutionKey.create(
-        configurationKey, toolchainTypeLabel, targetPlatformKey, availableExecutionPlatformKeys);
+        configurationKey,
+        toolchainTypeLabel,
+        targetPlatformKey,
+        availableExecutionPlatformKeys,
+        debugTarget);
   }
 
   /** {@link SkyKey} implementation used for {@link SingleToolchainResolutionFunction}. */
@@ -62,17 +80,21 @@ public SkyFunctionName functionName() {
 
     abstract ImmutableList<ConfiguredTargetKey> availableExecutionPlatformKeys();
 
+    abstract boolean debugTarget();
+
     @AutoCodec.Instantiator
     static SingleToolchainResolutionKey create(
         BuildConfigurationValue.Key configurationKey,
         Label toolchainTypeLabel,
         ConfiguredTargetKey targetPlatformKey,
-        List<ConfiguredTargetKey> availableExecutionPlatformKeys) {
+        List<ConfiguredTargetKey> availableExecutionPlatformKeys,
+        boolean debugTarget) {
       return new AutoValue_SingleToolchainResolutionValue_SingleToolchainResolutionKey(
           configurationKey,
           toolchainTypeLabel,
           targetPlatformKey,
-          ImmutableList.copyOf(availableExecutionPlatformKeys));
+          ImmutableList.copyOf(availableExecutionPlatformKeys),
+          debugTarget);
     }
   }
 

src/main/java/com/google/devtools/build/lib/skyframe/ToolchainContextKey.java

@@ -33,7 +33,8 @@ public static Builder key() {
     return new AutoValue_ToolchainContextKey.Builder()
         .requiredToolchainTypeLabels(ImmutableSet.of())
         .execConstraintLabels(ImmutableSet.of())
-        .forceExecutionPlatform(Optional.empty());
+        .forceExecutionPlatform(Optional.empty())
+        .debugTarget(false);
   }
 
   @Override
@@ -49,6 +50,8 @@ public SkyFunctionName functionName() {
 
   abstract Optional<Label> forceExecutionPlatform();
 
+  abstract boolean debugTarget();
+
   /** Builder for {@link ToolchainContextKey}. */
   @AutoValue.Builder
   public interface Builder {
@@ -62,6 +65,12 @@ public interface Builder {
 
     Builder execConstraintLabels(Label... execConstraintLabels);
 
+    Builder debugTarget(boolean flag);
+
+    default Builder debugTarget() {
+      return this.debugTarget(true);
+    }
+
     ToolchainContextKey build();
 
     Builder forceExecutionPlatform(Optional<Label> execPlatform);

src/main/java/com/google/devtools/build/lib/skyframe/ToolchainResolutionFunction.java

@@ -81,9 +81,10 @@ public UnloadedToolchainContext compute(SkyKey skyKey, Environment env)
 
       // Check if debug output should be generated.
       boolean debug =
-          configuration
-              .getFragment(PlatformConfiguration.class)
-              .debugToolchainResolution(key.requiredToolchainTypeLabels());
+          key.debugTarget()
+              || configuration
+                  .getFragment(PlatformConfiguration.class)
+                  .debugToolchainResolution(key.requiredToolchainTypeLabels());
 
       // Load the configured target for the toolchain types to ensure that they are valid and
       // resolve aliases.
@@ -115,7 +116,8 @@ public UnloadedToolchainContext compute(SkyKey skyKey, Environment env)
           resolvedToolchainTypeLabels,
           key.forceExecutionPlatform().map(platformKeys::find),
           builder,
-          platformKeys);
+          platformKeys,
+          key.debugTarget());
 
       UnloadedToolchainContext unloadedToolchainContext = builder.build();
       if (debug) {
@@ -354,7 +356,8 @@ private static void determineToolchainImplementations(
       ImmutableSet<Label> requiredToolchainTypeLabels,
       Optional<ConfiguredTargetKey> forcedExecutionPlatform,
       UnloadedToolchainContextImpl.Builder builder,
-      PlatformKeys platformKeys)
+      PlatformKeys platformKeys,
+      boolean debugTarget)
       throws InterruptedException, ValueMissingException, InvalidPlatformException,
           NoMatchingPlatformException, UnresolvedToolchainsException,
           InvalidToolchainLabelException {
@@ -367,7 +370,8 @@ private static void determineToolchainImplementations(
               configurationKey,
               toolchainTypeLabel,
               platformKeys.targetPlatformKey(),
-              platformKeys.executionPlatformKeys()));
+              platformKeys.executionPlatformKeys(),
+              debugTarget));
     }
 
     Map<SkyKey, ValueOrException2<NoToolchainFoundException, InvalidToolchainLabelException>>

src/test/shell/bazel/toolchain_test.sh

@@ -540,6 +540,29 @@ EOF
   expect_log 'Using toolchain: rule message: "this is the rule", toolchain extra_str: "foo from test_toolchain"'
 }
 
+function test_toolchain_debug_messages_target {
+  write_test_toolchain
+  write_test_rule
+  write_register_toolchain
+
+  mkdir -p demo
+  cat >> demo/BUILD <<EOF
+load('//toolchain:rule_use_toolchain.bzl', 'use_toolchain')
+# Use the toolchain.
+use_toolchain(
+    name = 'use',
+    message = 'this is the rule')
+EOF
+
+  bazel build \
+    --toolchain_resolution_debug=demo:use \
+    --incompatible_auto_configure_host_platform \
+    //demo:use &> $TEST_log || fail "Build failed"
+  expect_log 'ToolchainResolution:   Type //toolchain:test_toolchain: target platform @local_config_platform//.*: execution @local_config_platform//:host: Selected toolchain //:test_toolchain_impl_1'
+  expect_log 'ToolchainResolution: Target platform @local_config_platform//.*: Selected execution platform @local_config_platform//:host, type //toolchain:test_toolchain -> toolchain //:test_toolchain_impl_1'
+  expect_log 'Using toolchain: rule message: "this is the rule", toolchain extra_str: "foo from test_toolchain"'
+}
+
 function test_toolchain_use_in_aspect {
   write_test_toolchain
   write_test_aspect