bruno created this revision.
Herald added a subscriber: fhahn.
After https://reviews.llvm.org/D28299 gets in, clang will use PCMCache to
manage memory buffers for pcm files. This means the lock file manager isn't
needed for correctness anymore, but only as an optimization: clang waits for
other processes to finish up building a module if they are already doing it.
Emit remark instead of errors to notify users when a timeout occures and
actually build the module in case that happens.
https://reviews.llvm.org/D29001
Files:
include/clang/Basic/DiagnosticCommonKinds.td
lib/Frontend/CompilerInstance.cpp
Index: lib/Frontend/CompilerInstance.cpp
===
--- lib/Frontend/CompilerInstance.cpp
+++ lib/Frontend/CompilerInstance.cpp
@@ -1180,10 +1180,14 @@
llvm::LockFileManager Locked(ModuleFileName);
switch (Locked) {
case llvm::LockFileManager::LFS_Error:
- Diags.Report(ModuleNameLoc, diag::err_module_lock_failure)
+ // PCMCache takes care of correctness and locks are only necessary for
+ // performance. If there are errors creating the lock, do not use it
+ // and fallback to building the module ourselves.
+ Diags.Report(ModuleNameLoc, diag::remark_module_lock_failure)
<< Module->Name << Locked.getErrorMessage();
- return false;
-
+ // Clear the lock file in case there's some leftover around.
+ Locked.unsafeRemoveLockFile();
+ // FALLTHROUGH
case llvm::LockFileManager::LFS_Owned:
// We're responsible for building the module ourselves.
if (!compileModuleImpl(ImportingInstance, ModuleNameLoc, Module,
@@ -1203,11 +1207,14 @@
case llvm::LockFileManager::Res_OwnerDied:
continue; // try again to get the lock.
case llvm::LockFileManager::Res_Timeout:
-Diags.Report(ModuleNameLoc, diag::err_module_lock_timeout)
+// Since PCMCache takes care of correctness, we try waiting for another
+// process to complete the build so that this isn't done twice. If we
+// reach a timeout, it's not a problem, try to build it ourselves then.
+Diags.Report(ModuleNameLoc, diag::remark_module_lock_timeout)
<< Module->Name;
// Clear the lock file so that future invokations can make progress.
Locked.unsafeRemoveLockFile();
-return false;
+continue;
}
break;
}
Index: include/clang/Basic/DiagnosticCommonKinds.td
===
--- include/clang/Basic/DiagnosticCommonKinds.td
+++ include/clang/Basic/DiagnosticCommonKinds.td
@@ -88,10 +88,10 @@
"module '%0' %select{is incompatible with|requires}1 feature '%2'">;
def err_module_header_missing : Error<
"%select{|umbrella }0header '%1' not found">;
-def err_module_lock_failure : Error<
- "could not acquire lock file for module '%0': %1">, DefaultFatal;
-def err_module_lock_timeout : Error<
- "timed out waiting to acquire lock file for module '%0'">, DefaultFatal;
+def remark_module_lock_failure : Remark<
+ "could not acquire lock file for module '%0': %1">, InGroup;
+def remark_module_lock_timeout : Remark<
+ "timed out waiting to acquire lock file for module '%0'">,
InGroup;
def err_module_cycle : Error<"cyclic dependency in module '%0': %1">,
DefaultFatal;
def err_module_prebuilt : Error<
Index: lib/Frontend/CompilerInstance.cpp
===
--- lib/Frontend/CompilerInstance.cpp
+++ lib/Frontend/CompilerInstance.cpp
@@ -1180,10 +1180,14 @@
llvm::LockFileManager Locked(ModuleFileName);
switch (Locked) {
case llvm::LockFileManager::LFS_Error:
- Diags.Report(ModuleNameLoc, diag::err_module_lock_failure)
+ // PCMCache takes care of correctness and locks are only necessary for
+ // performance. If there are errors creating the lock, do not use it
+ // and fallback to building the module ourselves.
+ Diags.Report(ModuleNameLoc, diag::remark_module_lock_failure)
<< Module->Name << Locked.getErrorMessage();
- return false;
-
+ // Clear the lock file in case there's some leftover around.
+ Locked.unsafeRemoveLockFile();
+ // FALLTHROUGH
case llvm::LockFileManager::LFS_Owned:
// We're responsible for building the module ourselves.
if (!compileModuleImpl(ImportingInstance, ModuleNameLoc, Module,
@@ -1203,11 +1207,14 @@
case llvm::LockFileManager::Res_OwnerDied:
continue; // try again to get the lock.
case llvm::LockFileManager::Res_Timeout:
-Diags.Report(ModuleNameLoc, diag::err_module_lock_timeout)
+// Since PCMCache takes care of correctness, we try waiting for another
+// process to complete the build so that this isn't done twice. If we
+// reach a timeout, it's not a problem, try to build it ourselves then.
+Diags.Report(ModuleNameLoc,
