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https://issues.apache.org/jira/browse/DRILL-5052?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15732508#comment-15732508
]
ASF GitHub Bot commented on DRILL-5052:
---------------------------------------
Github user arina-ielchiieva commented on a diff in the pull request:
https://github.com/apache/drill/pull/660#discussion_r91531999
--- Diff:
exec/java-exec/src/main/java/org/apache/drill/exec/compile/CodeCompiler.java ---
@@ -33,36 +32,71 @@
import com.google.common.cache.LoadingCache;
import com.google.common.collect.Lists;
+/**
+ * Global code compiler mechanism shared by all threads and operators.
+ * Holds a single cache of generated code (keyed by code source) to
+ * prevent compiling identical code multiple times. Supports both
+ * the byte-code merging and plain-old Java methods of code
+ * generation and compilation.
+ */
+
public class CodeCompiler {
-// private static final org.slf4j.Logger logger =
org.slf4j.LoggerFactory.getLogger(CodeCompiler.class);
+
+ public static final String COMPILE_BASE = "drill.exec.compile";
+ String MAX_LOADING_CACHE_SIZE_CONFIG = COMPILE_BASE + ".cache_max_size";
private final ClassTransformer transformer;
+ private final ClassBuilder classBuilder;
+
+ /**
+ * Google Guava loading cache that defers creating a cache
+ * entry until first needed. Creation is done in a thread-safe
+ * way: if two threads try to create the same class at the same
+ * time, the first does the work, the second waits for the first
+ * to complete, then grabs the new entry.
+ */
+
private final LoadingCache<CodeGenerator<?>, GeneratedClassEntry> cache;
- private final DrillConfig config;
- private final OptionManager optionManager;
public CodeCompiler(final DrillConfig config, final OptionManager
optionManager) {
- transformer = new ClassTransformer(optionManager);
- final int cacheMaxSize =
config.getInt(ExecConstants.MAX_LOADING_CACHE_SIZE_CONFIG);
+ transformer = new ClassTransformer(config, optionManager);
+ classBuilder = new ClassBuilder(config, optionManager);
+ final int cacheMaxSize = config.getInt(MAX_LOADING_CACHE_SIZE_CONFIG);
cache = CacheBuilder.newBuilder()
.maximumSize(cacheMaxSize)
.build(new Loader());
- this.optionManager = optionManager;
- this.config = config;
}
+ /**
+ * Create a single instance of the generated class.
+ *
+ * @param cg
+ * @return
+ * @throws ClassTransformationException
+ * @throws IOException
+ */
@SuppressWarnings("unchecked")
- public <T> T getImplementationClass(final CodeGenerator<?> cg) throws
ClassTransformationException, IOException {
- return (T) getImplementationClass(cg, 1).get(0);
+ public <T> T createInstance(final CodeGenerator<?> cg) throws
ClassTransformationException, IOException {
+ return (T) createInstances(cg, 1).get(0);
}
+ /**
+ * Create multiple instances of the generated class.
+ *
+ * @param cg
+ * @param count
+ * @return
+ * @throws ClassTransformationException
+ * @throws IOException
--- End diff --
Description for param, return and exceptions?
> Option to debug generated Java code using an IDE
> ------------------------------------------------
>
> Key: DRILL-5052
> URL: https://issues.apache.org/jira/browse/DRILL-5052
> Project: Apache Drill
> Issue Type: Improvement
> Components: Execution - Codegen
> Affects Versions: 1.8.0
> Reporter: Paul Rogers
> Assignee: Paul Rogers
> Priority: Minor
>
> Drill makes extensive use of Java code generation to implement its operators.
> Drill uses sophisticated techniques to blend generated code with pre-compiled
> template code. An unfortunate side-effect of this behavior is that it is very
> difficult to visualize and debug the generated code.
> As it turns out, Drill's code-merge facility is, in essence, a do-it-yourself
> version of subclassing. The Drill "template" is the parent class, the
> generated code is the subclass. But, rather than using plain-old subclassing,
> Drill combines the code from the two classes into a single "artificial"
> packet of byte codes for which no source exists.
> Modify the code generation path to optionally allow "plain-old Java"
> compilation: the generated code is a subclass of the template. Compile the
> generated code as a plain-old Java class with no byte-code fix-up. Write the
> code to a known location that the IDE can search when looking for source
> files.
> With this change, developers can turn on the above feature, set a breakpoint
> in a template, then step directly into the generated Java code called from
> the template.
> This feature should be an option, enabled by developers when needed. The
> existing byte-code technique should be used for production code generation.
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