Implement a new InvalidateStructLayoutInfo method and add some comments

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@25304 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2006-01-14 00:07:34 +00:00
parent 2790383f73
commit 8dff24f378

View File

@ -131,6 +131,9 @@ TargetData::TargetData(const std::string &ToolName, const Module *M) {
BoolAlignment = 1;
}
/// Layouts - The lazy cache of structure layout information maintained by
/// TargetData.
///
static std::map<std::pair<const TargetData*,const StructType*>,
StructLayout> *Layouts = 0;
@ -165,6 +168,21 @@ const StructLayout *TargetData::getStructLayout(const StructType *Ty) const {
}
}
/// InvalidateStructLayoutInfo - TargetData speculatively caches StructLayout
/// objects. If a TargetData object is alive when types are being refined and
/// removed, this method must be called whenever a StructType is removed to
/// avoid a dangling pointer in this cache.
void TargetData::InvalidateStructLayoutInfo(const StructType *Ty) const {
if (!Layouts) return; // No cache.
std::map<std::pair<const TargetData*,const StructType*>,
StructLayout>::iterator I = Layouts->find(std::make_pair(this, Ty));
if (I != Layouts->end())
Layouts->erase(I);
}
static inline void getTypeInfo(const Type *Ty, const TargetData *TD,
uint64_t &Size, unsigned char &Alignment) {
assert(Ty->isSized() && "Cannot getTypeInfo() on a type that is unsized!");