reclaim my precious bit in FileInfo by ensuring that ContentCache objects
are 8-byte aligned.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@63630 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/clang/Basic/SourceManager.h b/include/clang/Basic/SourceManager.h
index c21c221..ce2aecc 100644
--- a/include/clang/Basic/SourceManager.h
+++ b/include/clang/Basic/SourceManager.h
@@ -144,7 +144,7 @@
FileInfo X;
X.IncludeLoc = IL.getRawEncoding();
X.Data = (uintptr_t)Con;
- assert((X.Data & 3) == 0 &&"ContentCache pointer insufficiently aligned");
+ assert((X.Data & 7) == 0 &&"ContentCache pointer insufficiently aligned");
assert((unsigned)FileCharacter < 4 && "invalid file character");
X.Data |= (unsigned)FileCharacter;
return X;
@@ -154,7 +154,7 @@
return SourceLocation::getFromRawEncoding(IncludeLoc);
}
const ContentCache* getContentCache() const {
- return reinterpret_cast<const ContentCache*>(Data & ~3UL);
+ return reinterpret_cast<const ContentCache*>(Data & ~7UL);
}
/// getCharacteristic - Return whether this is a system header or not.
diff --git a/lib/Basic/SourceManager.cpp b/lib/Basic/SourceManager.cpp
index 191b615..6f78ee1 100644
--- a/lib/Basic/SourceManager.cpp
+++ b/lib/Basic/SourceManager.cpp
@@ -160,8 +160,12 @@
ContentCache *&Entry = FileInfos[FileEnt];
if (Entry) return Entry;
- // Nope, create a new Cache entry.
- Entry = ContentCacheAlloc.Allocate<ContentCache>();
+ // 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);
new (Entry) ContentCache(FileEnt);
return Entry;
}
@@ -171,11 +175,12 @@
/// memory buffer. This does no caching.
const ContentCache*
SourceManager::createMemBufferContentCache(const MemoryBuffer *Buffer) {
- // Add a new ContentCache to the MemBufferInfos list and return it. We
- // must default construct the object first that the instance actually
- // stored within MemBufferInfos actually owns the Buffer, and not any
- // temporary we would use in the call to "push_back".
- ContentCache *Entry = ContentCacheAlloc.Allocate<ContentCache>();
+ // 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);
new (Entry) ContentCache();
MemBufferInfos.push_back(Entry);
Entry->setBuffer(Buffer);