> Please review several fixes and improvements to the `this-escape` lint > warning analyzer. > > The goal here is to apply some relatively simple logical fixes that improve > the precision and accuracy of the analyzer, and capture the remaining > low-hanging fruit so we can consider the analyzer relatively complete with > respect to what's feasible with its current design. > > Although the changes are small from a logical point of view, they generate a > fairly large patch due to impact of refactoring (sorry!). Most of the patch > derives from the first two changes listed below. > > The changes are summarized here: > > #### 1. Generalize how we categorize references > > The `Ref` class hierarchy models the various ways in which, at any point > during the execution of a constructor or some other method/constructor that > it invokes, there can be live references to the original object under > construction lying around. We then look for places where one of these `Ref`'s > might be passed to a subclass method. In other words, the analyzer keeps > track of these references and watches what happens to them as the code > executes so it can catch them trying to "escape". > > Previously the `Ref` categories were: > * `ThisRef` - The current instance of the (non-static) method or constructor > being analyzed > * `OuterRef` - The current outer instance of the (non-static) method or > constructor being analyzed > * `VarRef` - A local variable or method parameter currently in scope > * `ExprRef` - An object reference sitting on top of the Java execution stack > * `YieldRef` - The current switch expression's yield value(s) > * `ReturnRef` - The current method's return value(s) > > For each of those types, we further classified the "indirection" of the > reference, i.e., whether the reference was direct (from the thing itself) or > indirect (from something the thing referenced). > > The problem with that hierarchy is that we could only track outer instance > references that happened to be associated with the current instance. So we > might know that `this` had an outer instance reference, but if we said `var x > = this` we wouldn't know that `x` had an outer instance reference. > > In other words, we should be treating "via an outer instance" as just another > flavor of indirection along with "direct" and "indirect". > > As a result, with this patch the `OuterRef` class goes away and a new > `Indirection` enum has been created, with values `DIRECT`, `INDIRECT`, and > `OUTER`. > > #### 2. Track the types of all references > > By keeping track of the actual type of...
Archie Cobbs has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains eight commits: - Merge branch 'master' into JDK-8317376 - Merge branch 'master' into JDK-8317376 - Merge branch 'master' into JDK-8317376 - Merge branch 'master' into JDK-8317376 - Merge branch 'master' into JDK-8317376 - Javadoc++ - Merge branch 'master' into JDK-8317376 - Several improvements to the 'this' escape analyzer. - Track direct, indirect, and outer references for all Ref types. - Keep type information about all references to improve tracking precision. - Track enhanced for() invocations of iterator(), hasNext(), and next(). - Don't report an escape of a non-public outer instances as a leak. - Fix omitted tracking of references from newly instantiated instances. - Fix omitted tracking of leaks via lambda return values. - Remove unneccesary suppressions of this-escape lint warning. ------------- Changes: https://git.openjdk.org/jdk/pull/16208/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=16208&range=03 Stats: 869 lines in 19 files changed: 513 ins; 146 del; 210 mod Patch: https://git.openjdk.org/jdk/pull/16208.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/16208/head:pull/16208 PR: https://git.openjdk.org/jdk/pull/16208
