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Front-end: disable interface file locking for the -compile-module-from-interface action #32681

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Merged
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Jul 2, 2020
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Front-end: disable interface file locking for the -compile-module-from-interface action #32681

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11 changes: 9 additions & 2 deletions lib/Frontend/ArgsToFrontendOptionsConverter.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -102,8 +102,6 @@ bool ArgsToFrontendOptionsConverter::convert(
Opts.RemarkOnRebuildFromModuleInterface |=
Args.hasArg(OPT_Rmodule_interface_rebuild);

Opts.DisableInterfaceFileLock |= Args.hasArg(OPT_disable_interface_lockfile);

computePrintStatsOptions();
computeDebugTimeOptions();
computeTBDOptions();
Expand Down Expand Up @@ -149,6 +147,15 @@ bool ArgsToFrontendOptionsConverter::convert(
Opts.RequestedAction = determineRequestedAction(Args);
}

if (Opts.RequestedAction == FrontendOptions::ActionType::CompileModuleFromInterface) {
// The situations where we use this action, e.g. explicit module building and
// generating prebuilt module cache, don't need synchronization. We should avoid
// using lock files for them.
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What is the action for lazy module interface builds? It would be the only case where we would need the lock, is this right?

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That's correct. We only need lock file for regular compilation modes like -emit-module and -merge-modules because several compiler processes may attempt to build the same module.

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Aren't the sub invocations of the compiler for lazy module interface builds using the same -compile-module-from-interface flag? I'm worried this is disabling the lock even in other modes.

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Lazy module interface builds won't spawn a new front-end job to compile module from an interface file. Instead, the module building step happens implicitly in the main compilation action like -emit-module. We are moving towards explicitly module building where -compile-module-from-interface flag will be used, but that's where the lock file isn't necessary because all actions are performed synchronously.

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Alright, thanks for the explanation!

Opts.DisableInterfaceFileLock = true;
} else {
Opts.DisableInterfaceFileLock |= Args.hasArg(OPT_disable_interface_lockfile);
}

if (Opts.RequestedAction == FrontendOptions::ActionType::Immediate &&
Opts.InputsAndOutputs.hasPrimaryInputs()) {
Diags.diagnose(SourceLoc(), diag::error_immediate_mode_primary_file);
Expand Down