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
diff --git a/lib/Target/TargetData.cpp b/lib/Target/TargetData.cpp
index 75e76fe..40b762d 100644
--- a/lib/Target/TargetData.cpp
+++ b/lib/Target/TargetData.cpp
@@ -131,6 +131,9 @@
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 @@
}
}
+/// 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!");