Simplify codegen and debug info generation for block context parameters.
The exisiting code goes out of its way to put block parameters into an
alloca only at -O0, and then describes the funciton argument with a
dbg.declare, which is undocumented in the LLVM-CFE contract and does
not actually behave as intended after LLVM r642022.
This patch just generates the alloca unconditionally, the mem2reg pass
will eliminate it at -O1 and up anyway and points the dbg.declare to
the alloca as intended (which mem2reg will then correctly rewrite into
a dbg.value).
rdar://problem/
35043980
Differential Revision: https://reviews.llvm.org/D39305
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@316684
91177308-0d34-0410-b5e6-
96231b3b80d8