#include "llvm/ADT/IntrusiveRefCntPtr.h"
#include "llvm/ADT/PointerIntPair.h"
#include "llvm/ADT/PointerUnion.h"
+#include "llvm/Support/AlignOf.h"
#include "llvm/Support/Allocator.h"
#include "llvm/Support/DataTypes.h"
#include "llvm/Support/MemoryBuffer.h"
DoNotFreeFlag = 0x02
};
+ // Note that the first member of this class is an aligned character buffer
+ // to ensure that this class has an alignment of 8 bytes. This wastes
+ // 8 bytes for every ContentCache object, but each of these corresponds to
+ // a file loaded into memory, so the 8 bytes doesn't seem terribly
+ // important. It is quite awkward to fit this aligner into any other part
+ // of the class due to the lack of portable ways to combine it with other
+ // members.
+ llvm::AlignedCharArray<8, 1> NonceAligner LLVM_ATTRIBUTE_UNUSED;
+
/// \brief The actual buffer containing the characters from the input
/// file.
///
ContentCache &operator=(const ContentCache& RHS) LLVM_DELETED_FUNCTION;
};
+ // Assert that the \c ContentCache objects will always be 8-byte aligned so
+ // that we can pack 3 bits of integer into pointers to such objects.
+ static_assert(llvm::AlignOf<ContentCache>::Alignment >= 8,
+ "ContentCache must be 8-byte aligned.");
+
/// \brief Information about a FileID, basically just the logical file
/// that it represents and include stack information.
///
ContentCache *&Entry = FileInfos[FileEnt];
if (Entry) return Entry;
- // Nope, create a new Cache entry. Make sure it is at least 8-byte aligned
- // so that FileInfo can use the low 3 bits of the pointer for its own
- // nefarious purposes.
- unsigned EntryAlign = llvm::AlignOf<ContentCache>::Alignment;
- EntryAlign = std::max(8U, EntryAlign);
- Entry = ContentCacheAlloc.Allocate<ContentCache>(1, EntryAlign);
+ // Nope, create a new Cache entry.
+ Entry = ContentCacheAlloc.Allocate<ContentCache>();
if (OverriddenFilesInfo) {
// If the file contents are overridden with contents from another file,
/// memory buffer. This does no caching.
const ContentCache*
SourceManager::createMemBufferContentCache(const MemoryBuffer *Buffer) {
- // Add a new ContentCache to the MemBufferInfos list and return it. Make sure
- // it is at least 8-byte aligned so that FileInfo can use the low 3 bits of
- // the pointer for its own nefarious purposes.
- unsigned EntryAlign = llvm::AlignOf<ContentCache>::Alignment;
- EntryAlign = std::max(8U, EntryAlign);
- ContentCache *Entry = ContentCacheAlloc.Allocate<ContentCache>(1, EntryAlign);
+ // 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(Buffer);