These routines do not require executable stacks. However, by default ELFish
linkers may assume an executable stack on GNUish environments (and some non-GNU
ones too!). The GNU extension to add a note to indicate a non-executable stack
is honoured by these environments to mark the stack as non-executable (the
compiler normally emits this directive on appropriate targets whenever
possible). This allows normal builds from getting executable stacks due to
linking to the compiler rt builtins.
llvm-svn: 273500
Since these are primarily useful for deeply embedded targets where code size is
very important, they are each in a separate file making use of infrastructure
in sync-ops.h. This allows a linker to include just the functions that are
actually used.
rdar://problem/14736665
llvm-svn: 202812