I compile my code with -fsanitize=address switch. I have my own llvm pass that I want to execute. By the time the pass starts, I can see that the ASAN pass was made. Is it possible to run my pass before the ASAN pass?
I‘ve also tried to run my pass before the ASAN pass in different ways to instrument my program at BasicBlock-level.
And this seems to be available for me:
Register a "StandardPasses" with EP_EarlyAsPossible flag which makes your pass works earlier than ASAN.
static RegisterStandardPasses Y(PassManagerBuilder::EP_EarlyAsPossible,
[](const PassManagerBuilder &Builder,
legacy::PassManagerBase &PM) {
PM.add(new MyPass());
});
Compile your pass as a ".so" file.
Then use clang -Xclang -load -Xclang xxYourPassxx.so -fsanitize=address main.c -o main to compile your code.
I also compiled the main.bc & main.ll for checking. And the results show me that my instrumentation doesn't appear in ASAN's block (Because my pass runs before ASAN).
I have a simple Chapel program to test the NetCDF module:
use NetCDF;
use NetCDF.C_NetCDF;
var f: int = ncopen("ppt2020_08_20.nc", NC_WRITE);
var status: int = nc_close(f);
and when I compile with:
chpl -I/usr/include -L/usr/lib/x86_64-linux-gnu -lnetcdf hello.chpl
it produces a list of errors about SysCTypes:
$CHPL_HOME/modules/packages/NetCDF.chpl:57: error: 'c_int' undeclared (first use this function)
$CHPL_HOME/modules/packages/NetCDF.chpl:77: error: 'c_char' undeclared (first use this function)
...
Would anyone see what my error is? I tried adding use SysCTypes; to my program, but that didn't seem to have an effect.
Sorry for the delayed response and for this bad behavior. This is a bug that's crept into the NetCDF module which seems not to have been caught by Chapel's nightly testing. To work around it, edit $CHPL_HOME/modules/packages/NetCDF.chpl, adding the line:
public use SysCTypes, SysBasic;
within the declaration of the C_NetCDF module (around line 50 in my copy of the sources). If you would consider filing this bug as an issue on the Chapel GitHub issue tracker, that would be great as well, though we'll try to get this fixed in the next release in any case.
With that change, your program almost compiles for me, except that nc_close() takes a c_int argument rather than a Chapel int. You could either lean on Chapel's type inference to cause this to happen:
var f = ncopen("ppt2020_08_20.nc", NC_WRITE);
or explicitly declare f to be of type c_int:
var f: c_int = ncopen("ppt2020_08_20.nc", NC_WRITE);
And then as one final note, I believe you should be able to drop the -lnetcdf from your chpl command-line as using the NetCDF module should cause this requirement to automatically be added.
Thanks for bringing this bug to our attention!
I am very new to Frama-c and I got an issue when I am trying to open a C source file.
The error shows as
"fatal error: event.h: No such file or directory. Compilation terminated".
[kernel] Parsing FRAMAC_SHARE/libc/__fc_builtin_for_normalization.i (no preprocessing)
[kernel] Parsing WorkSpace/bipbuffer.c (with preprocessing)
[kernel] user error: failed to run: gcc -E -C -I. -dD -D__FRAMAC__ -nostdinc -D__FC_MACHDEP_X86_32 -I/usr/share/frama-c/libc -o '/tmp/bipbuffer.ce6d077.i' '/home/xxx/WorkSpace/bipbuffer.c' you may set the CPP environment variable to select the proper preprocessor command or use the option "-cpp-command".
[kernel] user error: stopping on file "/home/xxx/WorkSpace/bipbuffer.c" that has errors. Add'-kernel-msg-key pp' for preprocessing command.
So bascially I am trying to open a C source file but it returns an error like this. I aslo tried other very simple C files like hello world and other slicing functions, it works well.
I thought it was because I didn't have the dependencies of 'event.h' but it still return these errors after I installed the libevent dependencies. I am not sure if I need to manually set some path of the dependencies for frama-c
Here is part of the C file (Source link: https://memcached.org/) that I would like to open:
#include "stdio.h"
#include <stdlib.h>
/* for memcpy */
#include <string.h>
#include "bipbuffer.h"
static size_t bipbuf_sizeof(const unsigned int size)
{
return sizeof(bipbuf_t) + size;
}
int bipbuf_unused(const bipbuf_t* me)
{
if (1 == me->b_inuse)
/* distance between region B and region A */
return me->a_start - me->b_end;
else
return me->size - me->a_end;
}
......
Thanks,
Compilers and other tools working with C source code need to know where to find header files. There are some standard places where they look automatically, but Frama-C has fewer of those than (and different ones from) a normal compiler.
You need to find out where event.h is installed, then pass something like -cpp-extra-args "-I /path/to/directory/" to Frama-C. Pass the directory name only, not including the name event.h itself.
In addition to Isabelle Newbie's answer, I'd like to point out that the Chlorine version of Frama-C, whose beta has been recently announced, features a new option -json-compilation-database that attempts to read the arguments to be passed to the pre-processor from a compilation database.
Such database can be generated directly by cmake, but there are solutions for make-based project such as the one you refer to, in particular bear, which intercepts the commands launched by make to build the database.
Here's a detailed summary of how you could proceed, using the new -json-compilation-database option from Frama-C 17 Chlorine, plus an extra script list_files.py (which is not in the beta, but will be available in the final 17 release, and can be downloaded here):
Get the source files you want to analyze with Frama-C, run ./configure, and if possible try to disable optional dependencies from external libraries; for instance, some code bases include optional dependencies based on availability of libraries/system features, but have fallback options (resorting to standard C library or POSIX functions). The more you give Frama-C, the better the chances of analyzing it well, so if such external libraries are not essential, excluding them might help get a more "POSIXy" code, which should help. This is typically visible in config.h files, in macros commonly named HAVE_*.
Compile and install Build EAR or some equivalent tool to obtain a compile_commands.json file.
Run bear make (or cmake with flag CMAKE_EXPORT_COMPILE_COMMANDS) to get the compile_commands.json file.
Run the aforementioned list_files.py in the directory containing compile_commands.json to obtain the list of C sources used during compilation.
Run Frama-C (17 Chlorine or newer), giving it the list of sources found in the previous step, plus option -json-compilation-database . to parse the compile_commands.json and, hopefully, get the appropriate preprocessing flags.
Ideally, this should suffice, but in practice, this is rarely enough. In particular due to the presence of external libraries and non-C99, non-POSIX functions, the following steps are always needed.
6. Inclusion of external libraries
At this step, Frama-C will complain about the lack of event.h. You'll have to include the headers of this library yourself. Note: copying headers directly from your /usr/include is not likely to work, due to several architecture-specific definitions, especially files such as bits/*.h..
Instead, consider downloading the external libraries and preparing them (e.g. running ./configure at least). Then manually add the extra include directory via -cpp-extra-args="-I <path/to/your/sources/for/libevent.h>/include".
7. Inclusion of missing non-POSIX headers
Some other headers may be missing, in particular GNU- or BSD-specific sources (e.g. sysexits.h). Get these headers and add them when necessary. The error message in this case comes from the preprocessor (gcc) and is similar to this:
memcached.c:51:10: fatal error: sysexits.h: No such file or directory
#include <sysexits.h>
^~~~~~~~~~~~
compilation terminated.
8. Definition of missing non-POSIX types and constants
At this point, all necessary headers should be available, but parsing with Frama-C may still fail. This is due to usage of non-POSIX type definitions (e.g. caddr_t, struct ling), non-POSIX constants (e.g. MAXPATHLEN, SOCK_NONBLOCK, NI_MAXSERV). Error messages typically resemble the following:
[kernel] memcached.c:3261: Failure: Cannot resolve variable MAXPATHLEN
Constants are often easy to provide manually, by grepping what's available in your /usr/include.
Type definitions, on the other hand, may require some copy-pasting at the right places, especially if they depend on other types which are also missing. This step is hardly automatizable, but relatively straightforward once you get used to some specific error messages.
For instance, the following error message is related to a missing type definition (caddr_t):
[kernel] Parsing memcached.c (with preprocessing)
[kernel] memcached.c:1074:
syntax error:
Location: line 1074, between columns 38 and 47, before or at token: c
1072 *hdr++ = 0;
1073 *hdr++ = 0;
1074 assert((void *) hdr == (caddr_t)c->msglist[i].msg_iov[0].iov_base + UDP_HEADER_SIZE);
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
1075 }
1076
Note that the token just before c is (caddr_t), which has never been defined (it is often defined as either void * or char *).
The following error message is related to an incomplete type, i.e., a struct used somewhere but never defined:
[kernel] memcached.c:5811: User Error:
variable `ling' has initializer but incomplete type
It means that variable ling's type, which is struct linger (non-POSIX), has never been defined. In this case, we can copy it from our /usr/include/bits/socket.h:
struct linger
{
int l_onoff; /* Nonzero to linger on close. */
int l_linger; /* Time to linger. */
};
Note: if there are POSIX constants/definitions missing from Frama-C's libc, consider notifying its developers, or proposing pull requests in Frama-C's Github.
9. Fixing incompatible and missing function prototypes
Parsing is likely to succeed after the previous step, but it may still fail due to incompatible function prototypes. For instance, you may get:
[kernel] User Error: Incompatible declaration for usleep:
different integer types int and unsigned int
First declaration was at assoc.c:238
Current declaration is at items.c:1573
This is the consequence of a warning emitted earlier:
[kernel:typing:implicit-function-declaration] slabs.c:1150: Warning:
Calling undeclared function usleep. Old style K&R code?
It means that function usleep is called, but it does not have a prototype, therefore Frama-C uses the pre-C99 convention of "implicit int": it generates such a prototype, but later in the code, an actual declaration of usleep is found, and its type is not int. Hence the error.
To prevent this, you need to ensure usleep's prototype is properly included. Since it is not POSIX.1-2008, you need to either define/undefine the appropriate macros (see unistd.h), or add your own prototype.
At the end, this should allow Frama-C to parse the files and build an AST.
However, there are several missing prototypes yet; we were just lucky that none conflicted with actual declarations. Ideally, you'll consider the parsing stage done when there are no more messages such as implicit-function-declaration and similar warnings.
Some of the missing prototypes in memcached, such as getsubopt, are POSIX and should be integrated into Frama-C's standard library. Others might make part of a small library of non-standard stubs, to be reused for other software.
Contributing with results for future reuse
Successful conclusion of the parsing stage for such open source libraries is enough to consider them for integration into this repository of open source case studies, so that future users can start their analyses without having to redo all of these steps. (The repository is oriented towards Eva, but not exclusively: parsing is useful for all of Frama-C plug-ins.)
I got this error below and I can not find a solution. Does anybody know how
to fix this error?
rafael#ubuntu:~/avr/projeto$ clang -fsyntax-only -Os -I /usr/lib/avr/include -D__AVR_ATmega328P__ -DARDUINO=100 -Wno-ignored-attributes -Wno-attributes serial_tree.c
In file included from serial_tree.c:3:
In file included from /usr/lib/avr/include/util/delay.h:43:
/usr/lib/avr/include/util/delay_basic.h:108:5: error: invalid output
constraint
'=w' in asm
: "=w" (__count)
^
1 error generated.
util/delay.h is a Header from avr-libc, and the feature which you are using (some of the delay stuff) is using inline asm to implement it. avr-libc is written to be used with avr-gcc and uses features from avr-gcc like machine dependent constrains in inline asm. llvm does not recognize constraint "w", thus you have to use a different approach like using avr-gcc or porting that code to llvm.
avr-gcc also implements built-in function __builtin_avr_delay_cycles to implement wasting a specified number of clock cycles. If llvm is properly mimicking avr-gcc, then you can use that function as a starting point.
I'm using the excellent UNIX 'comm' command line utility in an application which I developed on a BSD platform (OSX). When I deployed to my Linux production server I found out that sadly, Ubuntu Linux's 'comm' utility does not take the -i flag to indicate that the lines should be compared case-insensitive. Apparently the POSIX standard does not require the -i option.
So... I'm in a bind. I really need the -i option that works so well on BSD. I've gone so far to try to compile the BSD comm.c source code on the Linux box but I got:
http://svn.freebsd.org/viewvc/base/user/luigi/ipfw3-head/usr.bin/comm/comm.c?view=markup&pathrev=200559
me#host:~$ gcc comm.c
comm.c: In function ‘getline’:
comm.c:195: warning: assignment makes pointer from integer without a cast
comm.c: In function ‘wcsicoll’:
comm.c:264: warning: assignment makes pointer from integer without a cast
comm.c:270: warning: assignment makes pointer from integer without a cast
/tmp/ccrvPbfz.o: In function `getline':
comm.c:(.text+0x421): undefined reference to `reallocf'
/tmp/ccrvPbfz.o: In function `wcsicoll':
comm.c:(.text+0x691): undefined reference to `reallocf'
comm.c:(.text+0x6ef): undefined reference to `reallocf'
collect2: ld returned 1 exit status
Does anyone have any suggestions as to how to get a version of comm on Linux that supports 'comm -i'?
Thanks!
You can add the following in comm.c:
void *reallocf(void *ptr, size_t size)
{
void *ret = realloc(ptr, size);
if (ret == NULL) {
free(ptr);
}
return ret;
}
You should be able to compile it then. Make sure comm.c has #include <stdlib.h> in it (it probably does that already).
The reason your compilation fails is because BSD comm.c uses reallocf() which is not a standard C function. But it is easy to write.
#OP ,there's no need to go to such length as to do your own src code compilation . Here's an alternative suggestion. Since you want case insensitive, you can just convert the cases in both files to lower (or upper case) using another tool such as tr before you pass the files to comm.
tr '[A-Z]' '[a-z]' <file1 > temp1
tr '[A-Z]' '[a-z]' <file2 > temp2
comm temp1 temp2
You could try to cat both files and pipe them to uniq -c -i. It'll show all lines in both files, with the number of appearances in the first column. As long as the original files don't have repeated lines, all lines with the first column >1 are lines common to both files.
Hope it helps!
Does anyone have any suggestions as to how to get a version of comm on Linux that supports 'comm -i'?
Not quite that; but have you checked if your requirements could be satisfied by the join utility? This one does have the -i option on Linux...