| commit | c2fadd146f0a752ee81a06c7129ac9667884fdea | [log] [tgz] |
|---|---|---|
| author | Christoffer Quist Adamsen <christofferqa@google.com> | Fri Aug 11 12:54:38 2023 +0200 |
| committer | Christoffer Quist Adamsen <christofferqa@google.com> | Fri Aug 11 12:54:38 2023 +0200 |
| tree | ebe7980e5cbdb7bea877ff4dc8c95cc22204f260 | |
| parent | f4b175aeed2975815f9425d52a52360aeceeb1e2 [diff] |
Avoid conflating register sets at move-exception
In-resolution moves to a move-exception instruction cannot be inserted before the move-exception instruction.
Previously, we worked around this by adding the in-resolution moves to a move-exception instruction as in-resolution moves to the goto instruction that is always after the move-exception instruction (since catch handlers are split blocks).
The in-resolution moves to the move-exception instruction must be inserted before any of the in-resolution moves to the goto instruction, however. By conflating the two in-resolution move sets, the subsequent parallel move scheduling may incorrectly reorder two moves.
Example: Consider that the in-resolution moves for the move-exception instruction is the set { move r11, r3 } and the in-resolution moves for the goto instruction is the set { move r1, r11 }.
The instructions must be laid out in sequence as:
move r11, r3
move r1, r11
When the two sets are conflated as { move r11, r3; move r1, r11 }, parallel move scheduling will instead layout the moves as follows, which may lead to arbitrary errors:
move r1, r11
move r11, r3
Fix: Instead of conflating the two in-resolution move sets, this CL simply inserts the in-resolution moves for the move-exception instruction immediately after the move-exception instruction.
Bug: b/293501981
Change-Id: I3975902ce63fb1f03914441c7c7357c839ff8a74The R8 repo contains two tools:
D8 is a replacement for the DX dexer and R8 is a replacement for the Proguard shrinking and minification tool.
The R8 project uses depot_tools from the chromium project to manage dependencies. Install depot_tools and add it to your path before proceeding.
The R8 project uses Java 8 language features and requires a Java 8 compiler and runtime system.
Typical steps to download and build:
$ git clone https://r8.googlesource.com/r8 $ cd r8 $ tools/gradle.py r8
The tools/gradle.py script will bootstrap using depot_tools to download a version of gradle to use for building on the first run. This will produce a jar file: build/libs/r8.jar which contains both R8 and D8.
The D8 dexer has a simple command-line interface with only a few options.
The most important option is whether to build in debug or release mode. Debug is the default mode and includes debugging information in the resulting dex files. Debugging information contains information about local variables used when debugging dex code. This information is not useful when shipping final Android apps to users and therefore, final builds should use the --release flag to remove this debugging information to produce smaller dex files.
Typical invocations of D8 to produce dex file(s) in the out directoy:
Debug mode build:
$ java -cp build/libs/r8.jar com.android.tools.r8.D8 --output out input.jar
Release mode build:
$ java -cp build/libs/r8.jar com.android.tools.r8.D8 --release --output out input.jar
The full set of D8 options can be obtained by running the command line tool with the --help option.
R8 is a Proguard replacement for whole-program optimization, shrinking and minification. R8 uses the Proguard keep rule format for specifying the entry points for an application.
Typical invocations of R8 to produce optimized dex file(s) in the out directory:
$ java -jar build/libs/r8.jar --release --output out --pg-conf proguard.cfg input.jar
The full set of R8 options can be obtained by running the command line tool with the --help option.
Typical steps to run tests:
$ tools/test.py --no_internal
The tools/test.py script will use depot_tools to download a lot of tests and test dependencies on the first run. This includes prebuilt version of the art runtime on which to validate the produced dex code.
In order to contribute to D8/R8 you have to sign the Contributor License Agreement. If your contribution is owned by your employer you need the Corporate Contributor License Agreement.
Once the license agreement is in place, please send an email to r8-dev@googlegroups.com to be added as a contributor.
After being added as a contributer you can upload your patches using git cl which is available in depot_tools. Once you have a change that you are happy with you should make sure that it passes all tests and then upload the change to our code review tool using:
$ git cl upload
On your first upload you will be asked to acquire credentials. Follow the instructions given by git cl upload.
On successful uploads a link to the code review is printed in the output of the upload command. In the code review tool you can assign reviewers and mark the change ready for review. At that point the code review tool will send emails to reviewers.
For questions, reach out to us at r8-dev@googlegroups.com.
For D8, find known issues in the D8 issue tracker or file a new D8 bug report.
For R8, find known issues in the R8 issue tracker or file a new R8 bug report.