Peter Collingbourne 5a81e14385 Introduce bitset metadata format and bitset lowering pass. ... This patch introduces a new mechanism that allows IR modules to co-operatively build pointer sets corresponding to addresses within a given set of globals. One particular use case for this is to allow a C++ program to efficiently verify (at each call site) that a vtable pointer is in the set of valid vtable pointers for the class or its derived classes. One way of doing this is for a toolchain component to build, for each class, a bit set that maps to the memory region allocated for the vtables, such that each 1 bit in the bit set maps to a valid vtable for that class, and lay out the vtables next to each other, to minimize the total size of the bit sets. The patch introduces a metadata format for representing pointer sets, an '@llvm.bitset.test' intrinsic and an LTO lowering pass that lays out the globals and builds the bitsets, and documents the new feature. Differential Revision: http://reviews.llvm.org/D7288 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230054 91177308-0d34-0410-b5e6-96231b3b80d8		2015-02-20 20:30:47 +00:00
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IPO	Introduce bitset metadata format and bitset lowering pass.	2015-02-20 20:30:47 +00:00
Utils	[cleanup] Re-sort all the #include lines in LLVM using	2015-01-14 11:23:27 +00:00
CMakeLists.txt	Introduce bitset metadata format and bitset lowering pass.	2015-02-20 20:30:47 +00:00
Makefile	Introduce bitset metadata format and bitset lowering pass.	2015-02-20 20:30:47 +00:00