Introduce a flag in SourceManager to treat non-system source files
as "volatile", meaning there's a high enough chance that they may
change while we are trying to use them.
This flag is only enabled by libclang.
Currently "volatile" source files will be stat'ed immediately
before opening them, because the file size stat info
may not be accurate since when we got it (e.g. from the PCH).
This avoids crashes when trying to reference mmap'ed memory
from a file whose size is not what we expect.
Note that there's still a window for a racing issue to occur
but the window for it should be way smaller than before.
We can consider later on to avoid mmap completely on such files.
rdar://11612916
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@160074 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Basic/FileManager.cpp b/lib/Basic/FileManager.cpp
index ddf8934..b921f3e 100644
--- a/lib/Basic/FileManager.cpp
+++ b/lib/Basic/FileManager.cpp
@@ -488,15 +488,21 @@
}
llvm::MemoryBuffer *FileManager::
-getBufferForFile(const FileEntry *Entry, std::string *ErrorStr) {
+getBufferForFile(const FileEntry *Entry, std::string *ErrorStr,
+ bool isVolatile) {
OwningPtr<llvm::MemoryBuffer> Result;
llvm::error_code ec;
+ uint64_t FileSize = Entry->getSize();
+ // If there's a high enough chance that the file have changed since we
+ // got its size, force a stat before opening it.
+ if (isVolatile)
+ FileSize = -1;
+
const char *Filename = Entry->getName();
// If the file is already open, use the open file descriptor.
if (Entry->FD != -1) {
- ec = llvm::MemoryBuffer::getOpenFile(Entry->FD, Filename, Result,
- Entry->getSize());
+ ec = llvm::MemoryBuffer::getOpenFile(Entry->FD, Filename, Result, FileSize);
if (ErrorStr)
*ErrorStr = ec.message();
@@ -508,7 +514,7 @@
// Otherwise, open the file.
if (FileSystemOpts.WorkingDir.empty()) {
- ec = llvm::MemoryBuffer::getFile(Filename, Result, Entry->getSize());
+ ec = llvm::MemoryBuffer::getFile(Filename, Result, FileSize);
if (ec && ErrorStr)
*ErrorStr = ec.message();
return Result.take();
@@ -516,7 +522,7 @@
SmallString<128> FilePath(Entry->getName());
FixupRelativePath(FilePath);
- ec = llvm::MemoryBuffer::getFile(FilePath.str(), Result, Entry->getSize());
+ ec = llvm::MemoryBuffer::getFile(FilePath.str(), Result, FileSize);
if (ec && ErrorStr)
*ErrorStr = ec.message();
return Result.take();
diff --git a/lib/Basic/SourceManager.cpp b/lib/Basic/SourceManager.cpp
index 5dc100a..9ec2474 100644
--- a/lib/Basic/SourceManager.cpp
+++ b/lib/Basic/SourceManager.cpp
@@ -97,7 +97,10 @@
}
std::string ErrorStr;
- Buffer.setPointer(SM.getFileManager().getBufferForFile(ContentsEntry, &ErrorStr));
+ bool isVolatile = SM.userFilesAreVolatile() && !IsSystemFile;
+ Buffer.setPointer(SM.getFileManager().getBufferForFile(ContentsEntry,
+ &ErrorStr,
+ isVolatile));
// If we were unable to open the file, then we are in an inconsistent
// situation where the content cache referenced a file which no longer
@@ -367,8 +370,10 @@
// Private 'Create' methods.
//===----------------------------------------------------------------------===//
-SourceManager::SourceManager(DiagnosticsEngine &Diag, FileManager &FileMgr)
+SourceManager::SourceManager(DiagnosticsEngine &Diag, FileManager &FileMgr,
+ bool UserFilesAreVolatile)
: Diag(Diag), FileMgr(FileMgr), OverridenFilesKeepOriginalName(true),
+ UserFilesAreVolatile(UserFilesAreVolatile),
ExternalSLocEntries(0), LineTable(0), NumLinearScans(0),
NumBinaryProbes(0), FakeBufferForRecovery(0),
FakeContentCacheForRecovery(0) {
@@ -426,7 +431,8 @@
/// getOrCreateContentCache - Create or return a cached ContentCache for the
/// specified file.
const ContentCache *
-SourceManager::getOrCreateContentCache(const FileEntry *FileEnt) {
+SourceManager::getOrCreateContentCache(const FileEntry *FileEnt,
+ bool isSystemFile) {
assert(FileEnt && "Didn't specify a file entry to use?");
// Do we already have information about this file?
@@ -455,6 +461,8 @@
new (Entry) ContentCache(FileEnt);
}
+ Entry->IsSystemFile = isSystemFile;
+
return Entry;
}
diff --git a/lib/Frontend/ASTUnit.cpp b/lib/Frontend/ASTUnit.cpp
index 7be25e9..ea2f773 100644
--- a/lib/Frontend/ASTUnit.cpp
+++ b/lib/Frontend/ASTUnit.cpp
@@ -215,7 +215,7 @@
PreambleRebuildCounter(0), SavedMainFileBuffer(0), PreambleBuffer(0),
NumWarningsInPreamble(0),
ShouldCacheCodeCompletionResults(false),
- IncludeBriefCommentsInCodeCompletion(false),
+ IncludeBriefCommentsInCodeCompletion(false), UserFilesAreVolatile(false),
CompletionCacheTopLevelHashValue(0),
PreambleTopLevelHashValue(0),
CurrentTopLevelHashValue(0),
@@ -658,7 +658,8 @@
RemappedFile *RemappedFiles,
unsigned NumRemappedFiles,
bool CaptureDiagnostics,
- bool AllowPCHWithCompilerErrors) {
+ bool AllowPCHWithCompilerErrors,
+ bool UserFilesAreVolatile) {
OwningPtr<ASTUnit> AST(new ASTUnit(true));
// Recover resources if we crash before exiting this method.
@@ -674,8 +675,10 @@
AST->CaptureDiagnostics = CaptureDiagnostics;
AST->Diagnostics = Diags;
AST->FileMgr = new FileManager(FileSystemOpts);
+ AST->UserFilesAreVolatile = UserFilesAreVolatile;
AST->SourceMgr = new SourceManager(AST->getDiagnostics(),
- AST->getFileManager());
+ AST->getFileManager(),
+ UserFilesAreVolatile);
AST->HeaderInfo.reset(new HeaderSearch(AST->getFileManager(),
AST->getDiagnostics(),
AST->ASTFileLangOpts,
@@ -1077,7 +1080,8 @@
LangOpts = &Clang->getLangOpts();
FileSystemOpts = Clang->getFileSystemOpts();
FileMgr = new FileManager(FileSystemOpts);
- SourceMgr = new SourceManager(getDiagnostics(), *FileMgr);
+ SourceMgr = new SourceManager(getDiagnostics(), *FileMgr,
+ UserFilesAreVolatile);
TheSema.reset();
Ctx = 0;
PP = 0;
@@ -1665,7 +1669,8 @@
ASTUnit *ASTUnit::create(CompilerInvocation *CI,
IntrusiveRefCntPtr<DiagnosticsEngine> Diags,
- bool CaptureDiagnostics) {
+ bool CaptureDiagnostics,
+ bool UserFilesAreVolatile) {
OwningPtr<ASTUnit> AST;
AST.reset(new ASTUnit(false));
ConfigureDiags(Diags, 0, 0, *AST, CaptureDiagnostics);
@@ -1673,7 +1678,9 @@
AST->Invocation = CI;
AST->FileSystemOpts = CI->getFileSystemOpts();
AST->FileMgr = new FileManager(AST->FileSystemOpts);
- AST->SourceMgr = new SourceManager(AST->getDiagnostics(), *AST->FileMgr);
+ AST->UserFilesAreVolatile = UserFilesAreVolatile;
+ AST->SourceMgr = new SourceManager(AST->getDiagnostics(), *AST->FileMgr,
+ UserFilesAreVolatile);
return AST.take();
}
@@ -1689,6 +1696,7 @@
bool PrecompilePreamble,
bool CacheCodeCompletionResults,
bool IncludeBriefCommentsInCodeCompletion,
+ bool UserFilesAreVolatile,
OwningPtr<ASTUnit> *ErrAST) {
assert(CI && "A CompilerInvocation is required");
@@ -1696,7 +1704,7 @@
ASTUnit *AST = Unit;
if (!AST) {
// Create the AST unit.
- OwnAST.reset(create(CI, Diags, CaptureDiagnostics));
+ OwnAST.reset(create(CI, Diags, CaptureDiagnostics, UserFilesAreVolatile));
AST = OwnAST.get();
}
@@ -1859,7 +1867,8 @@
bool PrecompilePreamble,
TranslationUnitKind TUKind,
bool CacheCodeCompletionResults,
- bool IncludeBriefCommentsInCodeCompletion) {
+ bool IncludeBriefCommentsInCodeCompletion,
+ bool UserFilesAreVolatile) {
// Create the AST unit.
OwningPtr<ASTUnit> AST;
AST.reset(new ASTUnit(false));
@@ -1872,6 +1881,7 @@
AST->IncludeBriefCommentsInCodeCompletion
= IncludeBriefCommentsInCodeCompletion;
AST->Invocation = CI;
+ AST->UserFilesAreVolatile = UserFilesAreVolatile;
// Recover resources if we crash before exiting this method.
llvm::CrashRecoveryContextCleanupRegistrar<ASTUnit>
@@ -1898,6 +1908,7 @@
bool IncludeBriefCommentsInCodeCompletion,
bool AllowPCHWithCompilerErrors,
bool SkipFunctionBodies,
+ bool UserFilesAreVolatile,
OwningPtr<ASTUnit> *ErrAST) {
if (!Diags.getPtr()) {
// No diagnostics engine was provided, so create our own diagnostics object
@@ -1957,6 +1968,7 @@
AST->ShouldCacheCodeCompletionResults = CacheCodeCompletionResults;
AST->IncludeBriefCommentsInCodeCompletion
= IncludeBriefCommentsInCodeCompletion;
+ AST->UserFilesAreVolatile = UserFilesAreVolatile;
AST->NumStoredDiagnosticsFromDriver = StoredDiagnostics.size();
AST->StoredDiagnostics.swap(StoredDiagnostics);
AST->Invocation = CI;
diff --git a/lib/Serialization/ASTReader.cpp b/lib/Serialization/ASTReader.cpp
index 46bd55e..4073e32 100644
--- a/lib/Serialization/ASTReader.cpp
+++ b/lib/Serialization/ASTReader.cpp
@@ -1127,8 +1127,9 @@
// This is the module's main file.
IncludeLoc = getImportLocation(F);
}
- FileID FID = SourceMgr.createFileID(File, IncludeLoc,
- (SrcMgr::CharacteristicKind)Record[2],
+ SrcMgr::CharacteristicKind
+ FileCharacter = (SrcMgr::CharacteristicKind)Record[2];
+ FileID FID = SourceMgr.createFileID(File, IncludeLoc, FileCharacter,
ID, BaseOffset + Record[0]);
SrcMgr::FileInfo &FileInfo =
const_cast<SrcMgr::FileInfo&>(SourceMgr.getSLocEntry(FID).getFile());
@@ -1145,7 +1146,8 @@
}
const SrcMgr::ContentCache *ContentCache
- = SourceMgr.getOrCreateContentCache(File);
+ = SourceMgr.getOrCreateContentCache(File,
+ /*isSystemFile=*/FileCharacter != SrcMgr::C_User);
if (OverriddenBuffer && !ContentCache->BufferOverridden &&
ContentCache->ContentsEntry == ContentCache->OrigEntry) {
unsigned Code = SLocEntryCursor.ReadCode();