change the serialized souper format a bit as suggested by Peter in email:
annotate each block with its number of predecessors; this simplifies parsing a
bit
bump LLVM in preparation for blog post
oops this slipped through my earlier patch to remove isTriviallyInvalid
Merge pull request #109 from regehr/blockpred

change the serialized souper format a bit as suggested by Peter in email
Merge pull request #113 from regehr/cleanup-triviallyinvalid

oops this slipped through my earlier patch to remove isTriviallyInvalid
Merge pull request #110 from regehr/bump-llvm

bump LLVM in preparation for blog post
ReplacementContext (was PrintContext) is produced by the LHS parser
and printer, and consumed by the RHS parser and printer; it ensures
that the mapping between names and pointers is consistent across
multiple conversions between Souper's internal and serialized
representations

also, making print names for vars optional and off by default
Merge pull request #111 from regehr/printcontext

PrintContext is produced by the LHS parser and printer, and
add a -souper-no-infer command line option that is useful for quickly loading
LHSs into the cache

add a tool cache_infer that runs infer() on each LHS in the cache; this is
useful for doing synthesis work without dealing with the tedium of building
software

add a couple of "parse only" options to souper-check so that cache_dump can
ensure that cache LHSs parse without incurrent the cost of running the solver

remove the spinner from cache_dump

a bit of refactoring in cache_dump
update the representation of the block instruction

We have changed the block's representation to "block n", so
update the relevant part in the documentation.
Merge pull request #118 from chenyang78/block_doc

update the representation of the block instruction
fix use after free bug
Merge pull request #120 from regehr/fix

fix use after free bug
Merge pull request #116 from regehr/noinfer

add a -souper-no-infer command line option that is useful for quickly...
sometimes clang/clang++ is used simply as an assembler or linker: no C/C++ files
are given on the command line. in this case it is unhappy about the unused
Souper arguments and prints unsightly warnings.  some build systems take these
as errors.  this patch detects whether any C/C++ files are being compiled and,
if not, doesn't give the problematic Souper arguments.

also: trivial patch to pass the -souper-ignore-solver-errors to souper if asked
by an environment variable
should have used the old ReplacementContext instead of making a fresh
one
Merge pull request #123 from regehr/check-fix

should have used the old ReplacementContext instead of making a fresh one
don't store UntypedInt with 4-bit APInt values

Integer 8 is represent as b1000 in a 4-bit APInt manner.
Later, when we translate this APInt value into a const using
APInt.sextOrTrunc, we get b11111000 back, which is not what
we want. The bad intepretation only occurs when
we infer the type of an integer, i.e., an integer without :iN.
Note that b11111000 is unsigned char 248, which is why we see
instruction "%8:i1 = eq 248:i8, %0" in John's example.

The fix is to use multiple of 5. It should always be safe.
Also, we won't increase too much memory usage because
it's only for parsing replacements, which are small.
Merge pull request #125 from chenyang78/parser

don't store UntypedInt with 4-bit APInt values
add Raimondas's souper2llvm tool

a couple of improvements to cache dump tool:
- call souper2llvm if asked
- keep track of optimization srclocs as we process things