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[Serialization] Allow either hash-based or mtime-based deps

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Add a bit to the module to determine whether the dependency’s stored bit pattern is a hash or an mtime.

Prebuilt modules store a hash of their dependencies because we can’t be sure their dependencies will have the same modtime as when they were built.
This commit is contained in:
Harlan Haskins
2019-02-13 17:24:24 -08:00
parent 0d951bf3db
commit 7d71579950
5 changed files with 160 additions and 31 deletions
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69
lib/Frontend/ParseableInterfaceSupport.cpp
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@@ -225,14 +225,40 @@ void ParseableInterfaceModuleLoader::configureSubInvocationInputsAndOutputs(
}
// Checks that a dependency read from the cached module is up to date compared
// to the interface file it represents.
static bool dependencyIsUpToDate(llvm::vfs::FileSystem &FS, FileDependency In,
StringRef ModulePath, DiagnosticEngine &Diags,
SourceLoc DiagLoc) {
auto Status = getStatusOfDependency(FS, ModulePath, In.Path, Diags, DiagLoc);
if (!Status) return false;
uint64_t mtime = Status->getLastModificationTime().time_since_epoch().count();
return Status->getSize() == In.Size && mtime == In.ModificationTime;
// to the interface file it represents. If it's up-to-date, return its status,
// so we can switch hash-based dependencies to mtimes after we've validated
// the hashes.
static Optional<llvm::vfs::Status>
dependencyIsUpToDate(llvm::vfs::FileSystem &FS, FileDependency In,
StringRef ModulePath, DiagnosticEngine &Diags,
SourceLoc DiagLoc) {
auto Status = getStatusOfDependency(FS, ModulePath, In.getPath(),
Diags, DiagLoc);
if (!Status) return None;
// If the sizes differ, then we know the file has changed.
if (Status->getSize() != In.getSize()) return None;
// Otherwise, if this dependency is verified by modification time, check
// it vs. the modification time of the file.
uint64_t mtime =
Status->getLastModificationTime().time_since_epoch().count();
if (In.isModificationTimeBased())
return mtime == In.getModificationTime() ? Status : None;
// Slow path: if the dependency is verified by content hash, check it vs. the
// hash of the file.
auto buf = getBufferOfDependency(FS, ModulePath, In.getPath(),
Diags, DiagLoc);
if (!buf) return None;
if (xxHash64(buf->getBuffer()) == In.getContentHash())
return Status;
return None;
}
}
// Check that the output .swiftmodule file is at least as new as all the
@@ -289,6 +315,7 @@ collectDepsForSerialization(llvm::vfs::FileSystem &FS,
CompilerInstance &SubInstance,
StringRef InPath, StringRef ModuleCachePath,
SmallVectorImpl<FileDependency> &Deps,
bool IsHashBased,
DiagnosticEngine &Diags, SourceLoc DiagLoc,
DependencyTracker *OuterTracker) {
auto DTDeps = SubInstance.getDependencyTracker()->getDependencies();
@@ -297,17 +324,25 @@ collectDepsForSerialization(llvm::vfs::FileSystem &FS,
llvm::StringSet<> AllDepNames;
for (auto const &DepName : InitialDepNames) {
if (AllDepNames.insert(DepName).second && OuterTracker) {
OuterTracker->addDependency(DepName, /*IsSystem=*/false);
OuterTracker->addDependency(DepName, /*IsSystem=*/false);
}
auto Status = getStatusOfDependency(FS, InPath, DepName, Diags, DiagLoc);
if (!Status)
return true;
auto DepBuf = getBufferOfDependency(FS, InPath, DepName, Diags, DiagLoc);
if (!DepBuf)
return true;
uint64_t mtime =
Status->getLastModificationTime().time_since_epoch().count();
Deps.push_back(FileDependency{Status->getSize(), mtime, DepName});
auto Status = getStatusOfDependency(FS, InPath, DepName, Diags, DiagLoc);
if (!Status)
return true;
if (IsHashBased) {
uint64_t hash = xxHash64(DepBuf->getBuffer());
Deps.push_back(
FileDependency::hashBased(DepName, Status->getSize(), hash));
} else {
uint64_t mtime =
Status->getLastModificationTime().time_since_epoch().count();
Deps.push_back(
FileDependency::modTimeBased(DepName, Status->getSize(), mtime));
}
if (ModuleCachePath.empty())
continue;
@@ -331,10 +366,10 @@ collectDepsForSerialization(llvm::vfs::FileSystem &FS,
return true;
}
for (auto const &SubDep : SubDeps) {
if (AllDepNames.insert(SubDep.Path).second) {
if (AllDepNames.insert(SubDep.getPath()).second) {
Deps.push_back(SubDep);
if (OuterTracker)
OuterTracker->addDependency(SubDep.Path, /*IsSystem=*/false);
OuterTracker->addDependency(SubDep.getPath(), /*IsSystem=*/false);
}
}
}