The problems with current beignet look to be:
- file timestamps in INPUT_FILES_BLOCK (some of beignet's .h files are
script-generated). This part can be fixed in beignet.
- build path captured in ORIGINAL_PCH_DIR. _Might_ be fixable in
beignet by using clang (...) > /path/to/beignet.pch instead of clang
(...) -o /path/to/beignet.pch, but that changes other things and I
haven't yet checked whether the result works.
Relevant part of llvm-bcanalyzer -dump:
</OPTIONS_BLOCK>
<ORIGINAL_FILE abbrevid=5 op0=1/> blob data =
'usr/lib/x86_64-linux-gnu/beignet/include/ocl.h'
<ORIGINAL_FILE_ID op0=1/>
<ORIGINAL_PCH_DIR abbrevid=6/> blob data =
'/home/rnpalmer/Debian/builds/stackbuild/beignet/obj-x86_64-linux-gnu/backend/src/libocl//usr/lib/x86_64-linux-gnu/beignet'
<INPUT_FILES_BLOCK NumWords=383 BlockCodeSize=4>
<INPUT_FILE abbrevid=4 op0=1 op1=5685 op2=1507369184 op3=0 op4=0/>
blob data = 'usr/lib/x86_64-linux-gnu/beignet/include/ocl_work_group.h'
<INPUT_FILE abbrevid=4 op0=2 op1=18934 op2=1507369184 op3=0 op4=0/>
blob data = 'usr/lib/x86_64-linux-gnu/beignet/include/ocl_simd.h'
(21 more similar lines - op2 are close but not all identical, and as
POSIX timestamps, near the beginning of the build)
