Bug 191050
| Summary: | Convert StringBuilder to be templatized on an OverflowHandler. | ||
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| Product: | WebKit | Reporter: | Mark Lam <mark.lam> |
| Component: | JavaScriptCore | Assignee: | Nobody <webkit-unassigned> |
| Status: | NEW | ||
| Severity: | Normal | ||
| Priority: | P2 | ||
| Version: | WebKit Nightly Build | ||
| Hardware: | Unspecified | ||
| OS: | Unspecified | ||
| Bug Depends on: | 184883 | ||
| Bug Blocks: | |||
Mark Lam
https://bugs.webkit.org/show_bug.cgi?id=184883 introduced the ConditionalCrashOnOverflow handler which is used in StringBuilder so that it can do a runtime determination whether to crash on overflows or not. Technically, StringBuilder can be templatized with an OverflowHandler template parameter instead (just like CheckedArithmetic) and produce more efficient code. However, when I attempted this (to templatize StringBuilder), I ran into an issue of clang not exporting explicitly instantiated some StringBuilder methods (instantiated for CrashOnOverflow and for RecordOverflow handlers). As a result, clients of JavaScriptCore were not able to link to those methods.
To work around this issue, I introduced the ConditionalCrashOnOverflow handler, thereby allowing StringBuilder to remain a plain class. If we can find a way to make clang export explicitly instantiated template methods, we should convert StringBuilder into a template and do away with the runtime shouldCrashOnOverflow checks in ConditionalCrashOnOverflow.
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