frama-c - Online in the Cloud

PROGRAM:

NAME

frama-c[.byte] - a static analyzer for C programs

frama-c-gui[.byte] - the graphical interface of frama-c

SYNOPSIS

frama-c [ options ] files

DESCRIPTION

frama-c is a suite of tools dedicated to the analysis of source code written in C. It
gathers several static analysis techniques in a single collaborative framework. This
framework can be extended by additional plugins placed in the $FRAMAC_PLUGIN directory.
The command

frama-c -help

will provide the full list of the plugins that are currently installed.

frama-c-gui is the graphical user interface of frama-c. It features the same options as
the command-line version.

frama-c.byte and frama-c-gui.byte are the ocaml bytecode versions of the command-line and
graphical user interface respectively.

By default, Frama-C recognizes .c files as C files needing pre-processing and .i files as
C files having been already pre-processed. Some plugins may extend the list of recognized
files. Pre-processing can be customized through the -cpp-command and -cpp-extra-args
options.

OPTIONS

Syntax

Options taking an additional parameter can also be written under the form

-option=param

This option is mandatory when param starts with a dash ('-')

Most options that takes no parameter have a corresponding

-no-option

option which has the opposite effect.

Help options

-help gives a short usage notice and the list of installed plugins.

-kernel-help
prints the list of options recognized by Frama-C's kernel

-verbose n
Sets verbosity level (default is 1). Setting it to 0 will output less progress
messages. This level can also be set on a per plugin basis, with option -plugin-
verbose n. Verbosity level of the kernel can be controlled with option
-kernel-verbose n.

-debug n
Sets debugging level (default is 0, meaning no debugging messages). This option
has the same per plugin (and kernel) specializations as -verbose.

-quiet Sets verbosity and debugging level to 0.

Options controlling Frama-C's kernel

-absolute-valid-range <min-max>
considers that all numerical addresses in the range min-max are valid. Bounds are
parsed as ocaml integer constants. By default, all numerical addresses are
considered invalid.

-add-path p1[,p2[...,pn]]
adds directories <p1> through <pn> to the list of directories in which plugins are
searched

[-no]-allow-duplication
allows duplication of small blocks during normalization of tests and loops.
Otherwise, normalization use labels and gotos. Bigger blocks and blocks with non-
trivial control flow are never duplicated. Defaults to yes.

[-no]-annot
reads ACSL annotation. This is the default. Annotation are not pre-processed by
default. Use -pp-annot for that.

-big-ints-hex max
integers larger than max are displayed in hexadecimal (by default, all integers are
displayed in decimal)

-check performs integrity checks on the internal AST (for developers only).

[-no]-collapse-call-cast
allows implicit cast between the value returned by a function and the lvalue it is
assigned to. Otherwise, a temporary variable is used and the cast is made explicit.
Defaults to yes.

[-no]-constfold
folds all syntactically constant expressions in the code before analyses. Defaults
to no.

[-no]-continue-annot-error
When analyzing an annotation, the default behavior (the -no version of this option)
when a typechecking error occurs is to reject the source file as is the case for
typechecking errors within the C code. With this option on, the typechecker will
only output a warning and discard the annotation but typechecking will continue
(errors in C code are still fatal, though).

-cpp-command cmd
Uses cmd as the command to pre-process C files. Defaults to the CPP environment
variable or to

gcc -C -E -I.

if it is not set. In order to preserve ACSL annotations, the preprocessor must keep
comments (the -C option for gcc). %1 and %2 can be used in cmd to denote the
original source file and the pre-processed file respectively

-cpp-extra-args args
Gives additional arguments to the pre-processor. This is only useful when
-preprocess-annot is set. Pre-processing annotations is done in two separate pre-
processing stages. The first one is a normal pass on the C code which retains macro
definitions. These are then used in the second pass during which annotations are
pre-processed. args are used only for the first pass, so that arguments that
should not be used twice (such as additional include directives or macro
definitions) must thus go there instead of -cpp-command.

[-no]-dynlink
When on, load all the dynamic plug-ins found in the search path (see -print-plugin-
path for more information on the default search path). Otherwise, only plugins
requested by -load-modules will be loaded. Default behavior is on.

-enums repr
Choose the way the representation of enumerated types is determined. frama-c
-enums help gives the list of available options. Default is gcc-enums

-float-digits n
When outputting floating-point numbers, display n digits. Defaults to 12.

-float-flush-to-zero
Floating point operations flush to zero

-float-hex
display floats as hexadecimal

-float-normal
display floats with standard Ocaml routine

-float-relative
display float interval as [ lower_bound++width ]

[-no]-force-rl-arg-eval
forces right to left evaluation order for arguments of function calls. Otherwise
the evaluation order is left unspecified, as in C standard. Defaults to no.

-journal-disable
Do not output a journal of the current session. See -journal-enable.

-journal-enable
On by default, dumps a journal of all the actions performed during the current
Frama-C session in the form of an ocaml script that can be replayed with -load-
script. The name of the script can be set with the -journal-name option.

-journal-name name
Set the name of the journal file (without the .ml extension). Defaults to
frama_c_journal.

-initialized-padding-locals
Implicit initialization of locals sets padding bits to 0. If false, padding bits
are left uninitialized (default to yes).

[-no]-keep-comments
Tries to preserve comments when pretty-printing the source code (defaults to no).

[-no]-keep-switch
When -simplify-cfg is set, keeps switch statements. Defaults to no.

-keep-unused-specified-functions
See -remove-unused-specified-functions

[-no]-lib-entry
Indicates that the entry point is called during program execution. This implies in
particular that global variables can not be assumed to have their initial values.
The default is -no-lib-entry: the entry point is also the starting point of the
program and globals have their initial value.

-load file
load the (previously saved) state contained in file.

-load-module m1[,m2[...,mn]]
loads the ocaml modules <m1>through <mn>. These modules must be .cmxsfiles for the
native code version of Frama-c and .cmoor.cmafiles for the bytecode version (see
the Dynlink section of Ocaml manual for more information). All modules which are
present in the plugin search paths are automatically loaded.

-load-script s1[,s2,[...,sn]]
loads the ocaml scripts <s1> through <sn>. The scripts must be .mlfiles. They
must be compilable relying only on Ocaml standard library and Frama-C's API. If
some custom compilation step is needed, compile them outside of Frama-C and use
-load-module instead.

-machdep machine
uses machine as the current machine-dependent configuration (size of the various
integer types, endiandness, ...). The list of currently supported machines is
available through -machdep help option. Default is x86_32

-main f
Sets f as the entry point of the analysis. Defaults to 'main'. By default, it is
considered as the starting point of the program under analysis. Use -lib-entry if f
is supposed to be called in the middle of an execution.

-obfuscate
prints an obfuscated version of the code (where original identifiers are replaced
by meaningless one) and exits. The correspondance table between original and new
symbols is kept at the beginning of the result.

-ocode file
redirects pretty-printed code to file instead of standard output.

[-no]-orig-name
During the normalization phase, some variables may get renamed when different
variable with the same name can co-exist (e.g. a global variable and a formal
parameter). When this option is on, a message is printed each time this occurs.
Defaults to no.

[-no]-warn-signed-downcast
generate alarms when signed downcasts may exceed the destination range (default to
no).

[-no]-warn-signed-overflow
generate alarms for signed operations that overflow (default to yes).

[-no]-warn-unsigned-downcast
generate alarms when unsigned downcasts may exceed the destination range (default
to no).

[-no]-warn-unsigned-overflow
generate alarms for unsigned operations that overflow (default to no).

[-no]-pp-annot
pre-process annotations. This is currently only possible when using gcc (or GNU
cpp) pre-processor. The default is to not pre-process annotations.

[-no]-print
pretty-prints the source code as normalized by CIL (defaults to no).

-print-libpath
outputs the directory where Frama-C kernel library is installed

-print-path
alias of -print-share-path

-print-plugin-path
outputs the directory where Frama-C searches its plugins (can be overidden by the
FRAMAC_PLUGIN variable and the -add-path option)

-print-share-path
outputs the directory where Frama-C stores its data (can be overidden by the
FRAMAC_SHARE variable)

-remove-unused-specified-functions
keeps function prototypes that have an ACSL specification but are not used in the
code. This is the default. Functions having the attribute FRAMAC_BUILTIN are always
kept.

-safe-arrays
For multidimensional arrays or arrays that are fields inside structs , assumes that
all accesses must be in bound (set by default). The opposite option is -unsafe-
arrays

-save file
Saves Frama-C's state into file after analyses have taken place.

[-no]-simplify-cfg
removes break, continue and switch statement before analyses. Defaults to no.

-then allows one to compose analyzes: a first run of Frama-C will occur with the options
before -then and a second run will be done with the options after -then on the
current project from the first run.

-then-on prj
Similar to -then except that the second run is performed in project prj If no such
project exists, Frama-C exits with an error.

-time file
appends user time and date in the given file when Frama-C exits.

-typecheck
forces typechecking of the source files. This option is only relevant if no further
analysis is requested (as typechecking will implicitely occurs before the analysis
is launched).

-ulevel n
syntactically unroll loops n times before the analysis. This can be quite costly
and some plugins (e.g. the value analysis) provide more efficient ways to perform
the same thing. See their respective manuals for more information. This can also
be activated on a per-loop basis via the loop pragma unroll <m> directive. A
negative value for n will inhibit such pragmas.

[-no]-unicode
outputs ACSL formulas with utf8 characters. This is the default. When given the
-no-unicode option, Frama-C will use the ASCII version instead. See the ACSL manual
for the correspondance.

-unsafe-arrays
see -safe-arrays

[-no]-unspecified-access
checks that read/write accesses occuring in unspecified order (according to the C
standard's notion of sequence point) are performed on separate locations. With
-no-unspecified-access, assumes that it is always the case (this is the default).

-version
outputs the version string of Frama-C

-warn-decimal-float <freq>
warns when a floating-point constant cannot be exactly represented (e.g. 0.1).
<freq> can be one of none, once, or all

[-no]-warn-undeclared-callee
warns when a function is called before it has been declared (set by default).
Frama-C

Plugins specific options

For each plugin, the command

frama-c -plugin-help

will give the list of options that are specific to the plugin.

EXIT STATUS

0 Successful execution

1 Invalid user input

2 User interruption (kill or equivalent)

3 Unimplemented feature

4 5 6 Internal error

125 Unknown error

Exit status greater than 2 can be considered as a bug (or a feature request for the case
of exit status 3) and may be reported on Frama-C's BTS (see below).

ENVIRONMENT VARIABLES

It is possible to control the places where Frama-C looks for its files through the
following variables.

FRAMAC_LIB
The directory where kernel's compiled interfaces are installed

FRAMAC_PLUGIN
The directory where Frama-C can find standard plug-ins. If you wish to have plugins
in several places, use -add-path instead.

FRAMAC_SHARE
The directory where Frama-C datas are installed.

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