Optimizations running even just with D8? [316744331]

Fixed

Bug

Status Update

No update yet.

Description

ms...@gmail.com

created issue #1

Dec 18, 2023 05:02AM

I work on the WALA static analysis framework (https://github.com/wala/WALA), and we use D8 to test WALA's Dalvik frontend. I've been trying to update to the latest D8 version and I ran into an issue with unexpected dead code elimination. Consider the following (weird) Java code from JLex:

	/* Open input stream. */
	m_instream = new java.io.FileReader(filename);
	if (null == m_instream)
	  {
	    System.out.println("Error: Unable to open input file "
			       + filename + ".");
	    return;
	  }

	/* Open output stream. */
	m_outstream 
	  = new java.io.PrintWriter(new java.io.BufferedWriter(
		new java.io.FileWriter(filename + ".java")));
	if (null == m_outstream)
	  {
	    System.out.println("Error: Unable to open output file "
			       + filename + ".java.");
	    return;
	  }

With the old D8 version we were using (2.2.42), the System.out.println calls would be present in the Dalvik bytecode output of D8, even though they are clearly dead code. But with verson 8.2.39, these calls are eliminated. I wouldn't expect D8 alone to be doing this optimization. Here is how we run D8 on a jar:

      D8.run(
          D8Command.builder()
              .addLibraryFiles(path_to_lib)
              .setMinApiLevel(26)
              .setOutput(tmpDir, OutputMode.DexIndexed)
              .addProgramFiles(Paths.get(jarFile))
              .build());

Is the new output expected? I.e., is this level of dead code elimination now "baked in" to D8? Thanks!

Comments

ze...@google.com <ze...@google.com> #2Dec 18, 2023 07:06AM

Reassigned to ze...@google.com.

Landed on main through https://r8-review.git.corp.google.com/c/r8/+/86022.

ms...@gmail.com <ms...@gmail.com> #3Dec 18, 2023 03:38PM

Project: r8
Branch: 8.2

commit ea625d87f24c2ae20f8705d04180cce9d98e448f
Author: Søren Gjesse <sgjesse@google.com>
Date: Wed Nov 22 14:14:53 2023

Desugar records again for Android U (API level 34)

Art had a bug in native record support in the initial release of
Android U.

This will be fixed with Art mainline updates, but turning record
desugaring on again for API level 34 to avoid hitting issues on
Android U where mainline updates are not been applied.

Also removed the predicate canUseNativeRecords and replaced with
isRecordsDesugaredForD8 and isRecordsDesugaredForR8. These two
together with runtimeWithRecordsSupport are now used in all record
tests.

Bug:

b/312443509

Change-Id: I111e9779b657492583cd7b9eb60788d8ec6d198e

M src/main/java/com/android/tools/r8/utils/InternalOptions.java
M src/test/java/com/android/tools/r8/TestBase.java
M src/test/java/com/android/tools/r8/ToolHelper.java
M src/test/java/com/android/tools/r8/desugar/records/EmptyRecordAnnotationTest.java
M src/test/java/com/android/tools/r8/desugar/records/RecordBlogTest.java
M src/test/java/com/android/tools/r8/desugar/records/RecordComponentAnnotationsTest.java
M src/test/java/com/android/tools/r8/desugar/records/RecordComponentSignatureTest.java
M src/test/java/com/android/tools/r8/desugar/records/RecordInterfaceTest.java
M src/test/java/com/android/tools/r8/desugar/records/RecordInvokeCustomSplitDesugaringTest.java
M src/test/java/com/android/tools/r8/desugar/records/RecordMergeTest.java
M src/test/java/com/android/tools/r8/desugar/records/SimpleRecordTest.java
M src/test/java/com/android/tools/r8/profile/art/completeness/RecordProfileRewritingTest.java

https://r8-review.googlesource.com/86240

ap...@google.com <ap...@google.com> #4Dec 19, 2023 07:17AM

Project: r8
Branch: 8.2

commit 136c261588ac8f3ac0212a78c4523d28e9e51b15
Author: Søren Gjesse <sgjesse@google.com>
Date: Wed Nov 22 14:16:25 2023

Version 8.2.38

Bug:

b/312443509

Change-Id: I7997e9387b94f42d7a3dd73ceccd055999d54941

M src/main/java/com/android/tools/r8/Version.java

https://r8-review.googlesource.com/86260

ze...@google.com <ze...@google.com> #5Dec 19, 2023 07:41AM

Thank you for your patience while our engineering team worked to resolve this issue. A fix for this issue is now available in:

Android Studio Hedgehog | 2023.1.1 Patch 1
Android Gradle Plugin 8.2.1

We encourage you to try the latest update.

If you notice further issues or have questions, please file a new bug report.

Thank you for taking the time to submit feedback — we really appreciate it!

ze...@google.com <ze...@google.com> #6Dec 19, 2023 07:53AM

I'm trying to make something happen today

ms...@gmail.com <ms...@gmail.com> #7Dec 19, 2023 04:34PM

Thank you!

ms...@gmail.com <ms...@gmail.com> #8Dec 28, 2023 05:43PM

I am curious, is this issue unlikely to be solved in the near future? If so, we will just code up a workaround for now in WALA, so we can continue with updating our r8 dependence. Thanks again!

sg...@google.com <sg...@google.com> #9Jan 2, 2024 08:26AM

It might take a bit of time to look into the concerns from comment #6, but the optimization should be disabled in debug mode if at all possible.

ap...@google.com <ap...@google.com> #10Jan 2, 2024 09:20AM

Project: r8
Branch: main

commit 6f3ea6138d0dbef4eb3b2b501b53ed48ea86c2d4
Author: Ian Zerny <zerny@google.com>
Date: Tue Dec 19 08:48:47 2023

Disable redundant load elimination in debug mode

Bug:

b/316744331

Bug:

b/218282718

Change-Id: I2df1712dfb920c68feeba2dcdcfc1c735e615993

M src/main/java/com/android/tools/r8/ir/conversion/passes/CodeRewriterPassCollection.java
M src/main/java/com/android/tools/r8/ir/optimize/RedundantFieldLoadAndStoreElimination.java
M src/test/java/com/android/tools/r8/regress/b316744331/Regress316744331Test.java

https://r8-review.googlesource.com/87300

ap...@google.com <ap...@google.com> #11Jan 4, 2024 08:11AM

Project: r8
Branch: main

commit 24659d5eae579cd1db20ffe88f6a634a333e9bfe
Author: Christoffer Adamsen <christofferqa@google.com>
Date: Wed Jan 03 16:11:05 2024

Reland "Disable redundant load elimination in debug mode"

Bug:

b/316744331

Bug:

b/218282718

Change-Id: I1c4fba711609183130735f8b93d0dbe627dec1c1

M src/main/java/com/android/tools/r8/ir/conversion/passes/CodeRewriterPassCollection.java
M src/main/java/com/android/tools/r8/ir/optimize/RedundantFieldLoadAndStoreElimination.java
M src/test/java/com/android/tools/r8/regress/b316744331/Regress316744331Test.java

https://r8-review.googlesource.com/87602

ap...@google.com <ap...@google.com> #12Jan 8, 2024 06:27PM

Project: platform/art
Branch: main

commit c0b9ea0f3b9dd56f6e301b96d48eb1c583497f24
Author: Christoffer Quist Adamsen <christofferqa@google.com>
Date: Mon Jan 08 10:44:08 2024

Update 911-get-stack-trace after disabling field load elimination

D8 8.4.5-dev disables redundant field load elimination in debug mode.

Bug: 316744331
Change-Id: Iee10c8656266b41ef108d5da1c1716ac27ea8ef9
Test: existing

M test/911-get-stack-trace/expected-stdout.txt

https://android-review.googlesource.com/2900587

ap...@google.com <ap...@google.com> #13Jan 9, 2024 09:43AM

Project: r8
Branch: 8.0

commit 44de2d3b1a19951abccf33e2412d625b11ca437e
Author: Ian Zerny <zerny@google.com>
Date: Tue Jan 09 09:54:22 2024

Version 8.0.75

Bug:

b/316744331

Change-Id: I7347b09a29ba027dabcb999348422802935d24c7

M src/main/java/com/android/tools/r8/Version.java

https://r8-review.googlesource.com/87970

ap...@google.com <ap...@google.com> #14Jan 9, 2024 09:43AM

Project: r8
Branch: 8.0

commit ab8f6074de78773d0a2796a95ee3285cc6598bcf
Author: Ian Zerny <zerny@google.com>
Date: Tue Jan 09 09:49:33 2024

Reland "Disable redundant load elimination in debug mode"

Notice: this cherry pick is written manually as this branch is from
before the introduction of code rewriter passes.

Bug:

b/316744331

Bug:

b/218282718

Change-Id: I1c4fba711609183130735f8b93d0dbe627dec1c1

M src/main/java/com/android/tools/r8/ir/optimize/RedundantFieldLoadAndStoreElimination.java

https://r8-review.googlesource.com/87927

ap...@google.com <ap...@google.com> #15Jan 9, 2024 02:24PM

Project: r8
Branch: 8.3

commit a7a3e45076d5fa6124376bd48022d4064b148df9
Author: Ian Zerny <zerny@google.com>
Date: Tue Jan 09 14:14:44 2024

Version 8.3.30

Bug:

b/316744331

Change-Id: I7edbb53ca57833a476577c26e766ca7aae001f86

M src/main/java/com/android/tools/r8/Version.java

https://r8-review.googlesource.com/87975

ap...@google.com <ap...@google.com> #16Jan 9, 2024 02:24PM

Project: r8
Branch: 8.3

commit bf16876c41ebee42408696d4be2fb6434f3cf341
Author: Ian Zerny <zerny@google.com>
Date: Tue Jan 09 14:13:53 2024

Reland "Disable redundant load elimination in debug mode"

Notice: this cherry pick is written manually as this branch is from
before the introduction of code rewriter passes.

Bug:

b/316744331

Bug:

b/218282718

Change-Id: I1c4fba711609183130735f8b93d0dbe627dec1c1

M src/main/java/com/android/tools/r8/ir/optimize/RedundantFieldLoadAndStoreElimination.java

https://r8-review.googlesource.com/87974

ap...@google.com <ap...@google.com> #17Jan 9, 2024 02:24PM

Project: r8
Branch: 8.2

commit fe9c21581262cb92258d217c1c4f52a652e64d4d
Author: Ian Zerny <zerny@google.com>
Date: Tue Jan 09 13:48:00 2024

Reland "Disable redundant load elimination in debug mode"

Notice: this cherry pick is written manually as this branch is from
before the introduction of code rewriter passes.

Bug:

b/316744331

Bug:

b/218282718

Change-Id: I1c4fba711609183130735f8b93d0dbe627dec1c1

M src/main/java/com/android/tools/r8/ir/optimize/RedundantFieldLoadAndStoreElimination.java

https://r8-review.googlesource.com/87972

ap...@google.com <ap...@google.com> #18Jan 9, 2024 02:24PM

Project: r8
Branch: 8.2

commit fd4b26bdc8af1f07472da2af2114e027e53a0efc
Author: Ian Zerny <zerny@google.com>
Date: Tue Jan 09 13:50:35 2024

Version 8.2.46

Bug:

b/316744331

Change-Id: I880c56fd07902c4697105778150be4cc16cd27a6

M src/main/java/com/android/tools/r8/Version.java

https://r8-review.googlesource.com/87973

ap...@google.com <ap...@google.com> #19Jan 9, 2024 02:24PM

Project: r8
Branch: 8.1

commit 59a7c1ac06e0fed85dd2f4f2a710f11fe433640b
Author: Ian Zerny <zerny@google.com>
Date: Tue Jan 09 12:13:37 2024

Reland "Disable redundant load elimination in debug mode"

Notice: this cherry pick is written manually as this branch is from
before the introduction of code rewriter passes.

Bug:

b/316744331

Bug:

b/218282718

Change-Id: I1c4fba711609183130735f8b93d0dbe627dec1c1

M src/main/java/com/android/tools/r8/ir/optimize/RedundantFieldLoadAndStoreElimination.java

https://r8-review.googlesource.com/87928

ap...@google.com <ap...@google.com> #20Jan 9, 2024 02:24PM

Project: r8
Branch: 8.1

commit 916a6d04b1c84a95bca923f2ea273fd7d52532fa
Author: Ian Zerny <zerny@google.com>
Date: Tue Jan 09 12:14:41 2024

Version 8.1.78

Bug:

b/316744331

Change-Id: I00bd2fac3a2548883838209d239b7fd200a54da0

M src/main/java/com/android/tools/r8/Version.java

https://r8-review.googlesource.com/87929

ze...@google.com <ze...@google.com> #21Jan 11, 2024 08:43AM

Marked as fixed.

A fix has been pushed to 8.0, 8.1, 8.2 and 8.3 branches for R8.

To use one of the fixed versions without AGP updates amend your settings.gradle or settings.gradle.kts file with:

pluginManagement {
    buildscript {
        repositories {
            mavenCentral()
            maven {
                url = uri("https://storage.googleapis.com/r8-releases/raw")
            }
        }
        dependencies {
           classpath("com.android.tools:r8:8.2.46") // <-- Use version matching your AGP here
        }
    }
}

Since AGP 8, the R8 versions follow those of AGP, so if using AGP 8.2 use the latest version on the R8 8.2 branch (for this issue 8.2.46 or any later patch version).

ms...@gmail.com <ms...@gmail.com> #22Jan 15, 2024 12:01AM

Thank you for fixing this issue!

an...@google.com <an...@google.com> #23Jan 23, 2024 06:00PM

Thank you for your patience while our engineering team worked to resolve this issue. A fix for this issue is now available in:

Android Studio Hedgehog | 2023.1.1 Patch 2
Android Gradle Plugin 8.2.2

We encourage you to try the latest update.

If you notice further issues or have questions, please file a new bug report.

Thank you for taking the time to submit feedback — we really appreciate it!

so...@google.com <so...@google.com> #24Jan 27, 2024 11:41PM

Comment added by automation: A postmortem has been automatically requested for this issue. Please author a postmortem on IRM. See go/android-postmortem-guidance for more context and details, including how to handle the case when this issue does not need a postmortem. If you have any questions not answered by go/android-postmortem-guidance, please email android-hygiene-tpm@, instead of reassigning the fixed bug. Thank you.

an...@google.com <an...@google.com> #25Feb 5, 2024 05:57PM

The fixes for this issue are now also available in:

Android Studio Iguana | 2023.2.1 RC 1
Android Gradle Plugin 8.3.0-rc01

We encourage you to try the latest update.

If you notice further issues or have questions, please file a new bug report.

Issue 316744331

Description

Issue summary

Comments

ze...@google.com <ze...@google.com> #2Dec 18, 2023 07:06AM

ms...@gmail.com <ms...@gmail.com> #3Dec 18, 2023 03:38PM

ap...@google.com <ap...@google.com> #4Dec 19, 2023 07:17AM

ze...@google.com <ze...@google.com> #5Dec 19, 2023 07:41AM

ze...@google.com <ze...@google.com> #6Dec 19, 2023 07:53AM

ms...@gmail.com <ms...@gmail.com> #7Dec 19, 2023 04:34PM

ms...@gmail.com <ms...@gmail.com> #8Dec 28, 2023 05:43PM

sg...@google.com <sg...@google.com> #9Jan 2, 2024 08:26AM

ap...@google.com <ap...@google.com> #10Jan 2, 2024 09:20AM

ap...@google.com <ap...@google.com> #11Jan 4, 2024 08:11AM

ap...@google.com <ap...@google.com> #12Jan 8, 2024 06:27PM

ap...@google.com <ap...@google.com> #13Jan 9, 2024 09:43AM

ap...@google.com <ap...@google.com> #14Jan 9, 2024 09:43AM

ap...@google.com <ap...@google.com> #15Jan 9, 2024 02:24PM

ap...@google.com <ap...@google.com> #16Jan 9, 2024 02:24PM

ap...@google.com <ap...@google.com> #17Jan 9, 2024 02:24PM

ap...@google.com <ap...@google.com> #18Jan 9, 2024 02:24PM

ap...@google.com <ap...@google.com> #19Jan 9, 2024 02:24PM

ap...@google.com <ap...@google.com> #20Jan 9, 2024 02:24PM

ze...@google.com <ze...@google.com> #21Jan 11, 2024 08:43AM

ms...@gmail.com <ms...@gmail.com> #22Jan 15, 2024 12:01AM

an...@google.com <an...@google.com> #23Jan 23, 2024 06:00PM

so...@google.com <so...@google.com> #24Jan 27, 2024 11:41PM

an...@google.com <an...@google.com> #25Feb 5, 2024 05:57PM

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