> Validate input in `java.lang.StringCoding` intrinsic Java wrappers, improve > their documentation, enhance the checks in the associated IR or assembly > code, and adapt them to cause VM crash on invalid input. > > ## Implementation notes > > The goal of the associated umbrella issue > [JDK-8156534](https://bugs.openjdk.org/browse/JDK-8156534) is to, for > `java.lang.String*` classes, > > 1. Move `@IntrinsicCandidate`-annotated `public` methods<sup>1</sup> (in Java > code) to `private` ones, and wrap them with a `public` ["front door" > method](https://github.com/openjdk/jdk/pull/24982#discussion_r2087493446) > 2. Since we moved the `@IntrinsicCandidate` annotation to a new method, > intrinsic mappings – i.e., associated `do_intrinsic()` calls in > `vmIntrinsics.hpp` – need to be updated too > 3. Add necessary input validation (range, null, etc.) checks to the newly > created public front door method > 4. Place all input validation checks in the intrinsic code (add if missing!) > behind a `VerifyIntrinsicChecks` VM flag > > Following preliminary work needs to be carried out as well: > > 1. Add a new `VerifyIntrinsicChecks` VM flag > 2. Update `generate_string_range_check` to produce a `HaltNode`. That is, > crash the VM if `VerifyIntrinsicChecks` is set and a Java wrapper fails to > spot an invalid input. > > <sup>1</sup> `@IntrinsicCandidate`-annotated constructors are not subject to > this change, since they are a special case. > > ## Functional and performance tests > > - `tier1` (which includes `test/hotspot/jtreg/compiler/intrinsics/string`) > passes on several platforms. Further tiers will be executed after integrating > reviewer feedback. > > - Performance impact is still actively monitored using > `test/micro/org/openjdk/bench/java/lang/String{En,De}code.java`, among other > tests. If you have suggestions on benchmarks, please share in the comments. > > ## Verification of the VM crash > > I've tested the VM crash scenario as follows: > > 1. Created the following test program: > > public class StrIntri { > public static void main(String[] args) { > Exception lastException = null; > for (int i = 0; i < 1_000_000; i++) { > try { > > jdk.internal.access.SharedSecrets.getJavaLangAccess().countPositives(new > byte[]{1,2,3}, 2, 5); > } catch (Exception exception) { > lastException = exception; > } > } > if (lastException != null) { > lastException.printStackTrace(); > } else { > System.out.println("completed"); > } > } > } > ...
Volkan Yazici has updated the pull request incrementally with three additional commits since the last revision: - Minimize the number of touched lines in `vmIntrinsics.hpp` - Remove Markdown-styling in comments - Improve wording of the `VerifyIntrinsicChecks` flag ------------- Changes: - all: https://git.openjdk.org/jdk/pull/25998/files - new: https://git.openjdk.org/jdk/pull/25998/files/6af98646..7c042b35 Webrevs: - full: https://webrevs.openjdk.org/?repo=jdk&pr=25998&range=01 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=25998&range=00-01 Stats: 14 lines in 5 files changed: 0 ins; 0 del; 14 mod Patch: https://git.openjdk.org/jdk/pull/25998.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/25998/head:pull/25998 PR: https://git.openjdk.org/jdk/pull/25998
