llvm-project/llvm/unittests/Transforms
Peter Collingbourne e6909c8e8b 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

llvm-svn: 230054
2015-02-20 20:30:47 +00:00
..
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