r312851 - Fix ownership of the MemoryBuffer in a FrontendInputFile.
Nico Weber via cfe-commits
cfe-commits at lists.llvm.org
Fri Mar 29 05:41:16 PDT 2019
(below)
On Fri, Sep 8, 2017 at 9:15 PM Richard Smith via cfe-commits <
cfe-commits at lists.llvm.org> wrote:
> Author: rsmith
> Date: Fri Sep 8 18:14:04 2017
> New Revision: 312851
>
> URL: http://llvm.org/viewvc/llvm-project?rev=312851&view=rev
> Log:
> Fix ownership of the MemoryBuffer in a FrontendInputFile.
>
> This fixes a possible crash on certain kinds of corrupted AST file, but
> checking in an AST file corrupted in just the right way will be a
> maintenance
> nightmare because the format changes frequently.
>
> Modified:
> cfe/trunk/include/clang/Basic/SourceManager.h
> cfe/trunk/include/clang/Frontend/FrontendOptions.h
> cfe/trunk/lib/Basic/SourceManager.cpp
> cfe/trunk/lib/Frontend/CompilerInstance.cpp
> cfe/trunk/lib/Frontend/FrontendAction.cpp
>
> Modified: cfe/trunk/include/clang/Basic/SourceManager.h
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/SourceManager.h?rev=312851&r1=312850&r2=312851&view=diff
>
> ==============================================================================
> --- cfe/trunk/include/clang/Basic/SourceManager.h (original)
> +++ cfe/trunk/include/clang/Basic/SourceManager.h Fri Sep 8 18:14:04 2017
> @@ -212,12 +212,6 @@ namespace SrcMgr {
> /// this content cache. This is used for performance analysis.
> llvm::MemoryBuffer::BufferKind getMemoryBufferKind() const;
>
> - void setBuffer(std::unique_ptr<llvm::MemoryBuffer> B) {
> - assert(!Buffer.getPointer() && "MemoryBuffer already set.");
> - Buffer.setPointer(B.release());
> - Buffer.setInt(0);
> - }
> -
> /// \brief Get the underlying buffer, returning NULL if the buffer is
> not
> /// yet available.
> llvm::MemoryBuffer *getRawBuffer() const { return
> Buffer.getPointer(); }
> @@ -816,7 +810,22 @@ public:
> SrcMgr::CharacteristicKind FileCharacter =
> SrcMgr::C_User,
> int LoadedID = 0, unsigned LoadedOffset = 0,
> SourceLocation IncludeLoc = SourceLocation()) {
> - return createFileID(createMemBufferContentCache(std::move(Buffer)),
> + return createFileID(
> + createMemBufferContentCache(Buffer.release(), /*DoNotFree*/
> false),
> + IncludeLoc, FileCharacter, LoadedID, LoadedOffset);
> + }
> +
> + enum UnownedTag { Unowned };
> +
> + /// \brief Create a new FileID that represents the specified memory
> buffer.
> + ///
> + /// This does no caching of the buffer and takes ownership of the
>
Is the "and takes ownership" part correct for this new overload?
> + /// MemoryBuffer, so only pass a MemoryBuffer to this once.
> + FileID createFileID(UnownedTag, llvm::MemoryBuffer *Buffer,
> + SrcMgr::CharacteristicKind FileCharacter =
> SrcMgr::C_User,
> + int LoadedID = 0, unsigned LoadedOffset = 0,
> + SourceLocation IncludeLoc = SourceLocation()) {
> + return createFileID(createMemBufferContentCache(Buffer,
> /*DoNotFree*/true),
> IncludeLoc, FileCharacter, LoadedID,
> LoadedOffset);
> }
>
> @@ -1699,7 +1708,7 @@ private:
>
> /// \brief Create a new ContentCache for the specified memory buffer.
> const SrcMgr::ContentCache *
> - createMemBufferContentCache(std::unique_ptr<llvm::MemoryBuffer> Buf);
> + createMemBufferContentCache(llvm::MemoryBuffer *Buf, bool DoNotFree);
>
> FileID getFileIDSlow(unsigned SLocOffset) const;
> FileID getFileIDLocal(unsigned SLocOffset) const;
>
> Modified: cfe/trunk/include/clang/Frontend/FrontendOptions.h
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Frontend/FrontendOptions.h?rev=312851&r1=312850&r2=312851&view=diff
>
> ==============================================================================
> --- cfe/trunk/include/clang/Frontend/FrontendOptions.h (original)
> +++ cfe/trunk/include/clang/Frontend/FrontendOptions.h Fri Sep 8 18:14:04
> 2017
> @@ -128,21 +128,24 @@ class FrontendInputFile {
> /// \brief The file name, or "-" to read from standard input.
> std::string File;
>
> - llvm::MemoryBuffer *Buffer;
> + /// The input, if it comes from a buffer rather than a file. This object
> + /// does not own the buffer, and the caller is responsible for ensuring
> + /// that it outlives any users.
> + llvm::MemoryBuffer *Buffer = nullptr;
>
> /// \brief The kind of input, e.g., C source, AST file, LLVM IR.
> InputKind Kind;
>
> /// \brief Whether we're dealing with a 'system' input (vs. a 'user'
> input).
> - bool IsSystem;
> + bool IsSystem = false;
>
> public:
> - FrontendInputFile() : Buffer(nullptr), Kind(), IsSystem(false) { }
> + FrontendInputFile() { }
> FrontendInputFile(StringRef File, InputKind Kind, bool IsSystem = false)
> - : File(File.str()), Buffer(nullptr), Kind(Kind), IsSystem(IsSystem) {
> }
> - FrontendInputFile(llvm::MemoryBuffer *buffer, InputKind Kind,
> + : File(File.str()), Kind(Kind), IsSystem(IsSystem) { }
> + FrontendInputFile(llvm::MemoryBuffer *Buffer, InputKind Kind,
> bool IsSystem = false)
> - : Buffer(buffer), Kind(Kind), IsSystem(IsSystem) { }
> + : Buffer(Buffer), Kind(Kind), IsSystem(IsSystem) { }
>
> InputKind getKind() const { return Kind; }
> bool isSystem() const { return IsSystem; }
>
> Modified: cfe/trunk/lib/Basic/SourceManager.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Basic/SourceManager.cpp?rev=312851&r1=312850&r2=312851&view=diff
>
> ==============================================================================
> --- cfe/trunk/lib/Basic/SourceManager.cpp (original)
> +++ cfe/trunk/lib/Basic/SourceManager.cpp Fri Sep 8 18:14:04 2017
> @@ -409,15 +409,16 @@ SourceManager::getOrCreateContentCache(c
> }
>
>
> -/// createMemBufferContentCache - Create a new ContentCache for the
> specified
> -/// memory buffer. This does no caching.
> -const ContentCache *SourceManager::createMemBufferContentCache(
> - std::unique_ptr<llvm::MemoryBuffer> Buffer) {
> +/// Create a new ContentCache for the specified memory buffer.
> +/// This does no caching.
> +const ContentCache *
> +SourceManager::createMemBufferContentCache(llvm::MemoryBuffer *Buffer,
> + bool DoNotFree) {
> // Add a new ContentCache to the MemBufferInfos list and return it.
> ContentCache *Entry = ContentCacheAlloc.Allocate<ContentCache>();
> new (Entry) ContentCache();
> MemBufferInfos.push_back(Entry);
> - Entry->setBuffer(std::move(Buffer));
> + Entry->replaceBuffer(Buffer, DoNotFree);
> return Entry;
> }
>
>
> Modified: cfe/trunk/lib/Frontend/CompilerInstance.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Frontend/CompilerInstance.cpp?rev=312851&r1=312850&r2=312851&view=diff
>
> ==============================================================================
> --- cfe/trunk/lib/Frontend/CompilerInstance.cpp (original)
> +++ cfe/trunk/lib/Frontend/CompilerInstance.cpp Fri Sep 8 18:14:04 2017
> @@ -838,8 +838,8 @@ bool CompilerInstance::InitializeSourceM
> : Input.isSystem() ? SrcMgr::C_System : SrcMgr::C_User;
>
> if (Input.isBuffer()) {
> - SourceMgr.setMainFileID(SourceMgr.createFileID(
> - std::unique_ptr<llvm::MemoryBuffer>(Input.getBuffer()), Kind));
> + SourceMgr.setMainFileID(SourceMgr.createFileID(SourceManager::Unowned,
> + Input.getBuffer(),
> Kind));
> assert(SourceMgr.getMainFileID().isValid() &&
> "Couldn't establish MainFileID!");
> return true;
>
> Modified: cfe/trunk/lib/Frontend/FrontendAction.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Frontend/FrontendAction.cpp?rev=312851&r1=312850&r2=312851&view=diff
>
> ==============================================================================
> --- cfe/trunk/lib/Frontend/FrontendAction.cpp (original)
> +++ cfe/trunk/lib/Frontend/FrontendAction.cpp Fri Sep 8 18:14:04 2017
> @@ -754,10 +754,11 @@ bool FrontendAction::BeginSourceFile(Com
> goto failure;
>
> // Reinitialize the main file entry to refer to the new input.
> - if (!CI.InitializeSourceManager(FrontendInputFile(
> - Buffer.release(),
> Input.getKind().withFormat(InputKind::Source),
> - CurrentModule->IsSystem)))
> - goto failure;
> + auto Kind = CurrentModule->IsSystem ? SrcMgr::C_System :
> SrcMgr::C_User;
> + auto &SourceMgr = CI.getSourceManager();
> + auto BufferID = SourceMgr.createFileID(std::move(Buffer), Kind);
> + assert(BufferID.isValid() && "couldn't creaate module buffer ID");
> + SourceMgr.setMainFileID(BufferID);
> }
> }
>
>
>
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