[Preamble] Reuse preamble even if an unsaved file does not exist
When a preamble is created an unsaved file not existing on disk is
already part of PrecompiledPreamble::FilesInPreamble. However, when
checking whether the preamble can be re-used, a failed stat of such an
unsaved file invalidated the preamble, which led to pointless and time
consuming preamble regenerations on subsequent reparses.
Do not require anymore that unsaved files should exist on disk.
This avoids costly preamble invalidations depending on timing issues for
the cases where the file on disk might be removed just to be regenerated
a bit later.
It also allows an IDE to provide in-memory files that might not exist on
disk, e.g. because the build system hasn't generated those yet.
Differential Revision: https://reviews.llvm.org/D41005
llvm-svn: 361226
diff --git a/clang/lib/Frontend/ASTUnit.cpp b/clang/lib/Frontend/ASTUnit.cpp
index 221bf97c..95d1bf2 100644
--- a/clang/lib/Frontend/ASTUnit.cpp
+++ b/clang/lib/Frontend/ASTUnit.cpp
@@ -1304,22 +1304,22 @@
PreambleInvocationIn.getDiagnosticOpts());
getDiagnostics().setNumWarnings(NumWarningsInPreamble);
- PreambleRebuildCounter = 1;
+ PreambleRebuildCountdown = 1;
return MainFileBuffer;
} else {
Preamble.reset();
PreambleDiagnostics.clear();
TopLevelDeclsInPreamble.clear();
PreambleSrcLocCache.clear();
- PreambleRebuildCounter = 1;
+ PreambleRebuildCountdown = 1;
}
}
// If the preamble rebuild counter > 1, it's because we previously
// failed to build a preamble and we're not yet ready to try
// again. Decrement the counter and return a failure.
- if (PreambleRebuildCounter > 1) {
- --PreambleRebuildCounter;
+ if (PreambleRebuildCountdown > 1) {
+ --PreambleRebuildCountdown;
return nullptr;
}
@@ -1329,6 +1329,8 @@
if (!AllowRebuild)
return nullptr;
+ ++PreambleCounter;
+
SmallVector<StandaloneDiagnostic, 4> NewPreambleDiagsStandalone;
SmallVector<StoredDiagnostic, 4> NewPreambleDiags;
ASTUnitPreambleCallbacks Callbacks;
@@ -1356,18 +1358,18 @@
if (NewPreamble) {
Preamble = std::move(*NewPreamble);
- PreambleRebuildCounter = 1;
+ PreambleRebuildCountdown = 1;
} else {
switch (static_cast<BuildPreambleError>(NewPreamble.getError().value())) {
case BuildPreambleError::CouldntCreateTempFile:
// Try again next time.
- PreambleRebuildCounter = 1;
+ PreambleRebuildCountdown = 1;
return nullptr;
case BuildPreambleError::CouldntCreateTargetInfo:
case BuildPreambleError::BeginSourceFileFailed:
case BuildPreambleError::CouldntEmitPCH:
// These erros are more likely to repeat, retry after some period.
- PreambleRebuildCounter = DefaultPreambleRebuildInterval;
+ PreambleRebuildCountdown = DefaultPreambleRebuildInterval;
return nullptr;
}
llvm_unreachable("unexpected BuildPreambleError");
@@ -1507,7 +1509,7 @@
AST->OnlyLocalDecls = OnlyLocalDecls;
AST->CaptureDiagnostics = CaptureDiagnostics;
if (PrecompilePreambleAfterNParses > 0)
- AST->PreambleRebuildCounter = PrecompilePreambleAfterNParses;
+ AST->PreambleRebuildCountdown = PrecompilePreambleAfterNParses;
AST->TUKind = Action ? Action->getTranslationUnitKind() : TU_Complete;
AST->ShouldCacheCodeCompletionResults = CacheCodeCompletionResults;
AST->IncludeBriefCommentsInCodeCompletion
@@ -1641,7 +1643,7 @@
std::unique_ptr<llvm::MemoryBuffer> OverrideMainBuffer;
if (PrecompilePreambleAfterNParses > 0) {
- PreambleRebuildCounter = PrecompilePreambleAfterNParses;
+ PreambleRebuildCountdown = PrecompilePreambleAfterNParses;
OverrideMainBuffer =
getMainBufferWithPrecompiledPreamble(PCHContainerOps, *Invocation, VFS);
getDiagnostics().Reset();
@@ -1819,7 +1821,7 @@
// If we have a preamble file lying around, or if we might try to
// build a precompiled preamble, do so now.
std::unique_ptr<llvm::MemoryBuffer> OverrideMainBuffer;
- if (Preamble || PreambleRebuildCounter > 0)
+ if (Preamble || PreambleRebuildCountdown > 0)
OverrideMainBuffer =
getMainBufferWithPrecompiledPreamble(PCHContainerOps, *Invocation, VFS);
diff --git a/clang/lib/Frontend/PrecompiledPreamble.cpp b/clang/lib/Frontend/PrecompiledPreamble.cpp
index 59467c3..25f128f 100644
--- a/clang/lib/Frontend/PrecompiledPreamble.cpp
+++ b/clang/lib/Frontend/PrecompiledPreamble.cpp
@@ -454,20 +454,33 @@
Status.getSize(), llvm::sys::toTimeT(Status.getLastModificationTime()));
}
+ // OverridenFileBuffers tracks only the files not found in VFS.
+ llvm::StringMap<PreambleFileHash> OverridenFileBuffers;
for (const auto &RB : PreprocessorOpts.RemappedFileBuffers) {
- llvm::vfs::Status Status;
- if (!moveOnNoError(VFS->status(RB.first), Status))
- return false;
-
- OverriddenFiles[Status.getUniqueID()] =
+ const PrecompiledPreamble::PreambleFileHash PreambleHash =
PreambleFileHash::createForMemoryBuffer(RB.second);
+ llvm::vfs::Status Status;
+ if (moveOnNoError(VFS->status(RB.first), Status))
+ OverriddenFiles[Status.getUniqueID()] = PreambleHash;
+ else
+ OverridenFileBuffers[RB.first] = PreambleHash;
}
// Check whether anything has changed.
for (const auto &F : FilesInPreamble) {
+ auto OverridenFileBuffer = OverridenFileBuffers.find(F.first());
+ if (OverridenFileBuffer != OverridenFileBuffers.end()) {
+ // The file's buffer was remapped and the file was not found in VFS.
+ // Check whether it matches up with the previous mapping.
+ if (OverridenFileBuffer->second != F.second)
+ return false;
+ continue;
+ }
+
llvm::vfs::Status Status;
if (!moveOnNoError(VFS->status(F.first()), Status)) {
- // If we can't stat the file, assume that something horrible happened.
+ // If the file's buffer is not remapped and we can't stat it,
+ // assume that something horrible happened.
return false;
}
@@ -481,7 +494,8 @@
continue;
}
- // The file was not remapped; check whether it has changed on disk.
+ // Neither the file's buffer nor the file itself was remapped;
+ // check whether it has changed on disk.
if (Status.getSize() != uint64_t(F.second.Size) ||
llvm::sys::toTimeT(Status.getLastModificationTime()) !=
F.second.ModTime)