PVS-Studio for Linux (CoreHard presentation)

What we had to test and
what we learnt during the
creation of the Linux version
of PVS-Studio
Svyatoslav Razmyslov
Evgeniy Ryzhkov
PVS-Studio
www.viva64.com

Who needs static code analysis?
• Beginners
• «Hindu programmers»
• Bad programmers

MySQL (C++)
A lot of similar strings.
Everything should be
fine.
static int rr_cmp(uchar *a, uchar *b)
{
if (a[0] != b[0])
return (int)a[0] - (int)b[0];
if (a[1] != b[1])
if (a[2] != b[2])
if (a[3] != b[3])
if (a[4] != b[4])
if (a[5] != b[5])
if (a[6] != b[6])
}

CryEngine 3 SDK (C++)
inline bool operator != (const SEfResTexture &m) const
{
if (stricmp(m_Name.c_str(), m_Name.c_str()) != 0 ||
m_TexFlags != m.m_TexFlags ||
m_bUTile != m.m_bUTile ||
.....
m_Sampler != m.m_Sampler)
return true;
return false;
}

Linux (C) kernel
static int tc_ctl_action(struct sk_buff *skb,
struct nlmsghdr *n)
{
struct net *net = sock_net(skb->sk);
struct nlattr *tca[TCA_ACT_MAX + 1];
u32 portid = skb ? NETLINK_CB(skb).portid : 0;
....
}
The function
got an
argument:
Dereferencing
Oops, it should be checked too.

These bugs have ALWAYS been there.
Taken from Cfront compiler, year 1985:
Pexpr expr::typ(Ptable tbl)
{
....
Pclass cl;
....
cl = (Pclass) nn->tp;
cl->permanent=1;
if (cl == 0) error('i',"%k %s'sT missing",CLASS,s);
....
}

Nothing has changed for the past 30
years. Modern Clang compiler:
Instruction *InstCombiner::visitGetElementPtrInst(....) {
....
Value *StrippedPtr = PtrOp->stripPointerCasts();
PointerType *StrippedPtrTy =
dyn_cast<PointerType>(StrippedPtr->getType());
if (!StrippedPtr)
return 0;
....
}

Static analysis methodology
 Automated code review
 Regular checks
 The human factor is avoided (it is lowered, to be exact).
 Specialized tools. The more the better.
But maybe not.

What did the PVS-Studio users wanted
from the Linux version of PVS-Studio?
 Command line utility;
“We don’t need integration with IDE!”
 We don’t need an installer
"We will set everything ourselves!»
 We don’t need the documentation
“We’ll run the program ourselves”

The first build and support
 The executable file is not a product
 Porting the code is only a small part of the work
 You cannot make conclusions without full-fledged
testing - comparison of testing on Windows and Linux

Myth of knowing build scripts
 Not all developers are completely familiar with the build
system
 People need some way of getting to know the product
without integrating and setting up
 This method should be quite reliable to leave a good
impression from the product

Support of multiple Linux
distributions

The choice of the monitoring technology
 (-) Clang scan-build
 (+) strace
 (+) JSON Compilation Database
 (+/-) RD_PRELOAD

Innumerable non-standard extensions of
GCC compilers

Closed testing of a Beta version
Episode 1
 The executable file of the analyzer with the setup script
 Online documentation
 Several different ways to analyze without the integration

Episode 2
 Support of non-standard compiler extensions
 Dealing with false alarms
 Creating Deb/Rpm packages
 Small tasks concerning the analyzer and the
documentation

Episode 3
 We decided not to use the config files for a quick check
 Improved work with the log of the strace utilitiy
 Work on the DEB/RPM packages
 Other tasks concerning the analyzer and the documentation

Episode 4
(Release Candidate)
 Heading towards the integration into large projects
 Implementation of various user requests
 Our own repositories for DEB/RPM packages*

Integration into Makefile/Makefile.am
.cpp.o:
$(CXX) $(CFLAGS) $(DFLAGS) $(INCLUDES) $< -o $@
pvs-studio --cfg $(CFG_PATH) --source-file $< --language C++
--cl-params $(CFLAGS) $(DFLAGS) $(INCLUDES) $<
 Details in the analyzer setup
 Incremental analysis
 Parallelization of the analysis on the build system level
 Other pluses of the build system

Integration into CMake /CLion
include(PVS-Studio.cmake)
pvs_studio_add_target(TARGET analyze
OUTPUT FORMAT errorfile
ANALYZE target LOG target.plog
LICENSE "/path/to/PVS-Studio.lic")

Integration into CMake/QtCreator
include(PVS-Studio.cmake)
pvs_studio_add_target(TARGET analyze
OUTPUT FORMAT errorfile
ANALYZE target LOG target.plog
LICENSE "/path/to/PVS-Studio.lic")

Integration into QMake/QtCreator
pvs_studio.target = pvs
pvs_studio.output = true
pvs_studio.license = /path/to/PVS-Studio.lic
pvs_studio.cfg = /path/to/PVS-Studio.cfg
pvs_studio.cxxflags = -std=c++14
pvs_studio.sources = $${SOURCES}
include(PVS-Studio.pri)

Conclusions made during the
development process
 Installation from a package or a repository
 Getting to know the product using a quick scan
 Integration into a project so that the developer may
have incremental analysis
 Configuring a complete analysis on the build server
 Additional comment - a crazy amount of the Linux projects analyzed, so
that the tool can be considered operational.

Questions?
 Release of PVS-Studio for Linux:
October 25, Tuesday
www.viva64.com
PVS-Studio checks C,C++ and C#

PVS-Studio for Linux (CoreHard presentation)

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