commit 40a737c8f369270490e00b69d98c8c8ea31ff697
author adonovan <adonovan@google.com> Wed Mar 11 14:32:19 2020 -0700
committer Copybara-Service <copybara-worker@google.com> Wed Mar 11 14:33:43 2020 -0700
tree eb569376a928d6080f17530d915063bb6dbe5ea6
parent 74dc4f3dba1c76efc24eb9dfbe21d9b38d42309f

bazel packages: add --record_rule_instantiation_callstack flag

This flag (default: false) causes each rule to record the Starlark
call stack at the moment of its instantiation.

The stacks are displayed by blaze query --output=build.

Example output:

        # /workspace/x/BUILD:2:1
        cc_library(
          name = "a",
          ...
        )
        # Instantiation stack:
        #   /workspace/x/inc.bzl:4:3 called from g
        #   /workspace/x/inc.bzl:2:3 called from f
        #   /workspace/x/BUILD:2:1   called from <toplevel>

By combining two optimizations, prefix sharing using a linked tree,
and element compression using packed integers, this feature
imposes an additional retained heap space cost of only 1.5%
for deps(//X) where X is Google's web server.

PiperOrigin-RevId: 300408104

src/main/java/com/google/devtools/build/lib/packages/RuleClass.java

diff --git a/src/main/java/com/google/devtools/build/lib/packages/RuleClass.java b/src/main/java/com/google/devtools/build/lib/packages/RuleClass.java
index 9b5504b..89b9edb 100644
--- a/src/main/java/com/google/devtools/build/lib/packages/RuleClass.java
+++ b/src/main/java/com/google/devtools/build/lib/packages/RuleClass.java
@@ -60,6 +60,7 @@
 import com.google.devtools.build.lib.syntax.Sequence;
 import com.google.devtools.build.lib.syntax.Starlark;
 import com.google.devtools.build.lib.syntax.StarlarkFunction;
+import com.google.devtools.build.lib.syntax.StarlarkThread;
 import com.google.devtools.build.lib.util.FileTypeSet;
 import com.google.devtools.build.lib.util.StringUtil;
 import com.google.devtools.build.lib.vfs.PathFragment;
@@ -1833,10 +1834,11 @@
       AttributeValues<T> attributeValues,
       EventHandler eventHandler,
       Location location,
+      List<StarlarkThread.CallStackEntry> callstack,
       AttributeContainer attributeContainer,
       boolean checkThirdPartyRulesHaveLicenses)
       throws LabelSyntaxException, InterruptedException, CannotPrecomputeDefaultsException {
-    Rule rule = pkgBuilder.createRule(ruleLabel, this, location, attributeContainer);
+    Rule rule = pkgBuilder.createRule(ruleLabel, this, location, callstack, attributeContainer);
     populateRuleAttributeValues(rule, pkgBuilder, attributeValues, eventHandler);
     checkAspectAllowedValues(rule, eventHandler);
     rule.populateOutputFiles(eventHandler, pkgBuilder);
@@ -1870,15 +1872,13 @@
       Label ruleLabel,
       AttributeValues<T> attributeValues,
       Location location,
+      List<StarlarkThread.CallStackEntry> callstack,
       AttributeContainer attributeContainer,
       ImplicitOutputsFunction implicitOutputsFunction)
       throws InterruptedException, CannotPrecomputeDefaultsException {
-    Rule rule = pkgBuilder.createRule(
-        ruleLabel,
-        this,
-        location,
-        attributeContainer,
-        implicitOutputsFunction);
+    Rule rule =
+        pkgBuilder.createRule(
+            ruleLabel, this, location, callstack, attributeContainer, implicitOutputsFunction);
     populateRuleAttributeValues(rule, pkgBuilder, attributeValues, NullEventHandler.INSTANCE);
     rule.populateOutputFilesUnchecked(NullEventHandler.INSTANCE, pkgBuilder);
     return rule;