The following flags are passed into lto1 and are not
meant to be used directly from the command line.
-fwpa
This option runs the serial part of the link-time optimizer
performing the inter-procedural propagation (WPA mode). The
compiler reads in summary information from all inputs and
performs an analysis based on summary information only. It
generates object files for subsequent runs of the link-time
optimizer where individual object files are optimized using both
summary information from the WPA mode and the actual function
bodies. It then drives the LTRANS phase.
-fltrans
This option runs the link-time optimizer in the
local-transformation (LTRANS) mode, which reads in output from a
previous run of the LTO in WPA mode. In the LTRANS mode, LTO
optimizes an object and produces the final assembly.
-fltrans-output-list=file
This option specifies a file to which the names of LTRANS output
files are written. This option is only meaningful in conjunction
with -fwpa.
-fresolution=file
This option specifies the linker resolution file. This option is
only meaningful in conjunction with -fwpa and as option
to pass through to the LTO linker plugin.