Undo AArch64 pass-by-pointer for X86-64

bug 19779488

AArch64's calling convention passes large objects by pointer/reference.
Consequently, RS functions exported in the driver need special handling
for x86-64.  This patch creates a new pass to libbcc that identifies
pointer arguments created due to the AArch64 convention and marks them
as pass-by-value.

Change-Id: I2e24edd9704e843b118f4c445cfd92f61f9de909
5 files changed