Use the Toolhelp32 API to enumerate loaded Win32 modules. #892
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This PR replaces our call to `EnumProcessModules()` with one to `CreateToolhelp32Snapshot(TH32CS_SNAPMODULE)`. Three reasons: 1. `EnumProcessModules()` requires us to specify a large, fixed-size buffer to contain all the `HMODULE` handles; 2. `EnumProcessModules()` does not own any references to the handles it returns, meaning that a module can be unloaded while we are iterating over them (while `CreateToolhelp32Snapshot()` temporarily bumps the refcounts of the handles it produces); and 3. `CreateToolhelp32Snapshot()` lets us produce a lazy sequence of `HMODULE` values rather than an array, letting us write somewhat Swiftier code that uses it. The overhead of using `CreateToolhelp32Snapshot()` was negligible (below the noise level when measuring).
grynspan
requested review from
stmontgomery,
dennisweissmann,
briancroom,
SeanROlszewski and
suzannaratcliff
as code owners
|
@swift-ci test |
compnerd
approved these changes
Jan 6, 2025
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This PR replaces our call to
EnumProcessModules()with one toCreateToolhelp32Snapshot(TH32CS_SNAPMODULE). Three reasons:EnumProcessModules()requires us to specify a large, fixed-size buffer to contain all theHMODULEhandles;EnumProcessModules()does not own any references to the handles it returns, meaning that a module can be unloaded while we are iterating over them (whileCreateToolhelp32Snapshot()temporarily bumps the refcounts of the handles it produces); andCreateToolhelp32Snapshot()lets us produce a lazy sequence ofHMODULEvalues rather than an array, letting us write somewhat Swiftier code that uses it.The overhead of using
CreateToolhelp32Snapshot()was negligible (below the noise level when measuring).Checklist: