* INSTALLATION:

	PAGAI needs:
	
	- GMP and MPFR. On Debian systems, install packages:
	
	  libmpfr-dev libgmp3-dev
	
	- CMake, for the compilation. On Debian systems, install packages:
	
	  cmake
	  
	  (you may want to install cmake-gui too for a graphical configuration
	  tool)
	
	- Yices, Z3, CUDD, LLVM, Apron and the PPL (can be automatically
	  installed for you). See the top of external/Makefile for required
	  versions of these tools. In particular, Pagai won't work if you
	  don't have the exact version of LLVM.
	
	- curl or wget, if you want automatic dependencies installation.
	
	The simplest way to compile PAGAI is to run:
	
	  ./autoinstall.sh
	
	from the toplevel. This will download and compile most dependencies
	for you (it takes time, and ~550Mb of disk space).

	PARALLEL_MAKE_OPTS=-j4 ./autoinstall.sh will compile dependencies
	trying to use 4 cores (adjust as needed).
	
	If you don't want the dependencies to be installed for you, run:
	
	  cmake .
	  make
	  
	from the toplevel.
	
	Alternatively, one can use an out-of-tree build with:
	
	  mkdir build
	  ../autoinstall-out-of-tree.sh
	
	or, without the external dependency installation:
	
	  mkdir build
	  cd build
	  cmake ..
	  make
	
	Variables (path to libraries, build options, ...) can be set for each
	build with e.g.
	
	  cmake -DSTATIC_LINK=ON .
	  cmake -i .
	  cmake-gui .
	
	
	For running Pagai, you should make sure your PATH variable contains the
	directory of the SMT solver you want to use (e.g. Z3, CVC4, etc.)
	
	On MacOS, please compile with clang and not g++: there are strange
	template instantiations errors with g++, leading to duplicate symbols
	when linking.


* Optional APRON extensions
PAGAI can use APRON linked with
- the Parma Polyhedra Library http://bugseng.com/products/ppl/ (-DENABLE_PPL)
- OptOptagons, from ETHZ https://github.com/eth-srl/OptOctagon (-DENABLE_OPT_OCT)

* USAGE: 

	- With a C input
	If you want to use Pagai with a C input, you first need to setup a pagai.conf file in the same directory as the Pagai executable. This conf file contains only one variable so far, named ResourceDir. This variable should be set to the path of your LLVM/Clang installation. In particular, make sure you set ResourceDir so that the path $(ResourceDir)/lib/clang/3.4/include/ exists and contains e.g. float.h.
	
	The pagai.conf file should have the form:
	"ResourceDir <dir>"
	
	example:
	--> cat pagai.conf
	ResourceDir /Users/julien/work/pagai/external/llvm
	
	
	- With a LLVM .bc input
		The pagai.conf file is only used for compiling C/C++ code into LLVM bitcode. If you directly give to Pagai a bitcode file, it will process it. Note that you will need to compile into bitcode with clang and the -g and -emit-llvm arguments.
	
	pagai -h should give you the list of arguments:
	
	Options:
	  -i [ --input ] arg              input
	  -h [ --help ]                   Print help messages
	  -I [ --include-path ] arg       include path (same as -I for clang)
	  -s [ --solver ] arg (=z3_api)   * z3 
	                                  * z3_qfnra
	                                  * mathsat
	                                  * smtinterpol
	                                  * cvc3
	                                  * cvc4
	                                  * z3_api
	                                  
	  -d [ --domain ] arg (=pk)       abstract domain
	                                  * box (Apron boxes)
	                                  * oct (Octagons)
	                                  * pk (NewPolka strict polyhedra)
	                                  * pkeq (NewPolka linear equalities)
	  -t [ --technique ] arg (=lw+pf) technique
	                                  * lw (Lookahead Widening, SAS'06)
	                                  * g (Guided Static Analysis, SAS'07)
	                                  * pf (Path Focusing, SAS'11)
	                                  * lw+pf (SAS'12)
	                                  * s (simple abstract interpretation)
	                                  * dis (lw+pf, using disjunctive invariants)
	                                  * pf_incr
	                                  * incr
	  --new-narrowing                 When the decreasing sequence fails (SAS12)
	  --main arg                      label name of the entry point
	  --no-undefined-check            no undefined check
	  --pointers                      pointers
	  --optimize                      optimize
	  --instcombining                 instcombining
	  --loop-unroll                   unroll loops
	  --skipnonlinear                 ignore non linear arithmetic
	  --noinline                      do not inline functions
	  -o [ --output ] arg             C output
	  --output-bc arg                 LLVM IR output
	  --output-bc-v2 arg              LLVM IR output (v2)
	  --svcomp                        SV-Comp mode
	  --wcet                          wcet mode
	  --debug                         debug
	  -c [ --compare ] arg            compare list of techniques
	  --comparedomains                compare abstract domains
	  --printformula                  print SMT formula
	  --printall                      print all
	  --quiet                         quiet mode
	  --dump-ll                       dump analyzed ll file
	  --force-old-output              use old output
	  --timeout arg                   timeout
	  --log-smt                       write all the SMT requests into a log file
	  --annotated arg                 name of the annotated C file
	  --domain2 arg                   not for use
	  --new-narrowing2                not for use
	
	
	
* EXAMPLE 
	
	--> ./pagai ../ex/wcet_bicycle2.c
	// ResourceDir is /Users/julien/work/pagai/external/llvm/lib/clang/3.4
	// analysis: AIopt
	/* processing Function bicycle */
	#include "../pagai_assert.h"
	
	void bicycle() {
	  int /* reachable */
	      count=0, phase=0;
	  for(int i=0; i<10000; // safe
	                        i++) {
	    /* invariant:
	    -2*count+phase+3*i = 0
	    14998-count+phase >= 0
	    1-phase >= 0
	    phase >= 0
	    count-2*phase >= 0
	    */
	    if (phase == 0) {
			// safe
			count += 2; phase = 1;
		} else if (phase == 1) {
			// safe
			count += 1; phase = 0;
		}
	  }
	  /* assert OK */
	  assert(count <= 15000);
	/* reachable */
	}