Undefined behavior sanitizer suppression file: failed to parse suppressions - clang

After compiling an application with clang 3.6 using -fsanitize=undefined,
I'm trying to start the instrumented program while using a suppression file to ignore some of the errors:
UBSAN_OPTIONS="suppressions=ubsan.supp" ./app.exe
The suppression file ubsan.supp contains:
signed-integer-overflow:example.c
This leads to an error message:
UndefinedBehaviorSanitizer: failed to parse suppressions
The same occurs with a gcc 4.9 build.
The only documentation I can find is http://clang.llvm.org/docs/UndefinedBehaviorSanitizer.html, which is for clang 3.9, while I use 3.6 (which doesn't have documentation for ubsan included).
Can anyone provide working examples for ubsan suppression files, that work in clang 3.6?
Edit: By browsing the source code of ubsan, I found that the only valid suppression type might be "vptr_check" - dunno which version I was looking at though.
Can anyone confirm that in clang 3.9 more suppression types are available?

I didn't spend the time to find out exactly which suppressions were available in clang-3.6, but it appears that in clang-3.7 only vptr_check is available as a suppression. Starting in clang-3.8, the suppressions list is defined to be the list of checks, plus vptr_check.
In clang-3.9 the checks available are:
"undefined"
"null"
"misaligned-pointer-use"
"alignment"
"object-size"
"signed-integer-overflow"
"unsigned-integer-overflow"
"integer-divide-by-zero"
"float-divide-by-zero"
"shift-base"
"shift-exponent"
"bounds"
"unreachable"
"return"
"vla-bound"
"float-cast-overflow"
"bool"
"enum"
"function"
"returns-nonnull-attribute"
"nonnull-attribute"
"vptr"
"cfi"
"vptr_check"

I'd tried it by creating three files, compile.sh, main.cpp and suppressions.supp as shown below. The unsigned-integer-overflow is not a part of undefined that's why it needs to be included specifically. This works on my machine with clang-3.9.
So, I'd guess more suppression types are valid in clang-3.9.
# compile.sh
set -x
UBSAN_OPTIONS=suppressions=suppressions.supp:print_stacktrace=1 #:help=1
export UBSAN_OPTIONS
clang++-3.9 -g -std=c++11 -fsanitize=undefined -fno-omit-frame-pointer -fsanitize=unsigned-integer-overflow main.cpp
./a.out
// main.cpp
#include <bits/stdc++.h>
#include <bits/stl_tree.h>
using namespace std;
int main(int argc, char **argv) {
unsigned int k = UINT_MAX;
k += 1;
return 0;
}
# suppressions.supp
unsigned-integer-overflow:main.cpp

Related

XCode Build System: Messing up preprocessors definitions and included header files?

First question here.
I have some troubles with the XCode Build System, specifically with preprocessor definitions.
I'm trying to define a macro for the objective-c runtime to avoid enforcing the dispatch functions to be cast to an appropriate function pointer type. The usual way to go would be to use #define OBJC_OLD_DISPATCH_PROTOTYPES and then include the header on the next line. Once the header gets included, the macro is already defined and the header is configured accordingly.
But that's where it starts to get weird!
The macro is not recognized at all and the header gets included as if the #define statement was not there so it fails to #define OBJC_OLD_DISPATCH_PROTOTYPES and it gets (re?)defined as 0.
main.c
#include <stdio.h>
#define OBJC_OLD_DISPATCH_PROTOTYPES 1
#include <objc/objc-runtime.h>
int main(int argc, const char * argv[]) {
// From there:
// - Build System: OBJC_OLD_DISPATCH_PROTOTYPES is always 0, except if defined in build settings
// - Clang (only): OBJC_OLD_DISPATCH_PROTOTYPES is 1
printf("%d\n", OBJC_OLD_DISPATCH_PROTOTYPES);
}
The build system acts as expected when the preprocessor macro is defined in the project build settings under the "Apple Clang - Preprocessing" section. It defines the global macro using the -D parameter of clang making it available to any files used by the project.
However, source code compiles correctly when I use clang from a terminal using clang main.c.
Could someone tell me what I need to configure for the build system to behave normally?
It gives a warning when building with Xcode IDE:
Ambiguous expansion of macro 'OBJC_OLD_DISPATCH_PROTOTYPES'
and the output is indeed 0 using Xcode directly, but 1 with clang main.c. The difference is that Xcode uses clang with enabled modules by default: You get the same warning on the command line if you enable modules there:
clang -fmodules main.c
Solution
In Xcode, select the target, go to the "Build Settings" tab and in the "Apple Clang - Language - Modules" section, switch the "Enable Modules (C and Objective-C)" entry to 'NO':
Then you get the expected result in both cases, regardless of whether you use Xcode or Clang on the command line.
Explanation:
If you use modules the following happens:
instead of the preprocessor including the text and compiling the result, a binary representation of the module is used
modules are (independently) precompiled, i.e. they use the definitions from the time the module was precompiled
consequently, preprocess definitions from the code before the include/import statement have no effect on the module (nor on other imported modules).
if modules are enabled, not only #imports are affected, but also #includes are translated into module imports under the hood
So you have a contradictory definitions for the OBJC_OLD_DISPATCH_PROTOTYPES.
The precompiled module uses a 0 for OBJC_OLD_DISPATCH_PROTOTYPES and you redefine it as 1.
BTW: if you use
#define OBJC_OLD_DISPATCH_PROTOTYPES 0
then you use the same definition that the precompiled module is using and therefore there is no warning about an ambiguous expansion of the macro even if modules are enabled.
Without enabled modules, the preprocessor includes the text, compiles the result and returns the expected result, i.e. in objc.h the desired typedef are used.

QtCreator annotation compiler does not find stdbool.h

I'm using QtCreator 4.11.2 , installed via MSYS2, with ClangCodeModel enabled.
Here is my program (this is the result of creating a New Non-QT Plain C Application):
#include <stdio.h>
#include <stdbool.h>
_Bool a;
bool b;
int main()
{
printf("Hello World!\n");
return 0;
}
The .pro file is unchanged from the default:
TEMPLATE = app
CONFIG += console
CONFIG -= app_bundle
CONFIG -= qt
SOURCES += \
main.c
The annotation compiler highlights an error saying stdbool.h cannot be found.
But it does not give an error for _Bool a; , so it is clearly running in C99 mode but has some problem with include paths. The "Follow symbol under cursor" option works, opening stdbool.h.
My question is: How do I configure include paths for the annotation compiler or otherwise fix this problem?
I have been unable to figure out how to set options for the annotation compiler or even which compiler binary it is using . Under Tools > Options > C++ > Code Model > Diagnostic Configuration it lets me add -W flags but does not let me add -I flags, a red message pops up saying the option is invalid.
Under Tools > Options > C++ Code Model inspector, there are no diagnostic messages, and the Code Model Inspecting Log shows stdbool.h being correctly found and parsed, as msys64/mingw64/lib/gcc/x86_64-w64-mingw32/9.3.0/include/stdbool.h.
If I disable the ClangCodeModel plugin then there are no errors , but I would like to use the clang version if it can be made to work as in general it has good diagnostics.
The result of clang --version in a shell prompt is:
clang version 10.0.0 (https://github.com/msys2/MINGW-packages.git 3f880aaba91a3d9cdfb222dc270274731a2119a9)
Target: x86_64-w64-windows-gnu
Thread model: posix
InstalledDir: F:\Prog\msys64\mingw64\bin
and if I compile this same source code using clang outside of QtCreator, it compiles and runs correctly with no diagnostics. So the annotation compiler is clearly not the same as the commandline clang?
The Kit I have selected in QtCreator is the autodetected Desktop Qt MinGW-w64 64bit (MSYS2)
The exact same symptoms occur if I make a Plain C++ project and try to include stdbool.h (which is required to exist by the C++ Standard, although deprecated), although interestingly it does accept <cstdbool>.
I have found a workaround of sorts: including in the .pro file the line:
INCLUDEPATH += F:/Prog/msys64/mingw64/lib/gcc/x86_64-w64-mingw32/9.3.0/include/
causes the annotation compiler to work correctly, however this is undesirable as I'd have to keep changing it whenever I switch Kits because it also passes this to the actual build compiler, not just the annotation compiler.
Create file stdbool.h in C:\msys64\mingw64\x86_64-w64-mingw32\include and copy paste this code:
/* Copyright (C) 1998-2017 Free Software Foundation, Inc.
This file is part of GCC.
GCC is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3, or (at your option)
any later version.
GCC is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
Under Section 7 of GPL version 3, you are granted additional
permissions described in the GCC Runtime Library Exception, version
3.1, as published by the Free Software Foundation.
You should have received a copy of the GNU General Public License and
a copy of the GCC Runtime Library Exception along with this program;
see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
<http://www.gnu.org/licenses/>. */
/*
* ISO C Standard: 7.16 Boolean type and values <stdbool.h>
*/
#ifndef _STDBOOL_H
#define _STDBOOL_H
#ifndef __cplusplus
#define bool _Bool
#define true 1
#define false 0
#else /* __cplusplus */
/* Supporting _Bool in C++ is a GCC extension. */
#define _Bool bool
#if __cplusplus < 201103L
/* Defining these macros in C++98 is a GCC extension. */
#define bool bool
#define false false
#define true true
#endif
#endif /* __cplusplus */
/* Signal that all the definitions are present. */
#define __bool_true_false_are_defined 1
#endif /* stdbool.h */
Note
Creating a manual file stdbool.h works for me but its a sketchy and a temporary solution for now. Don't use this if you feel its too sketcy. I would rather use a alternative solution than this hack if it exist. This solution might not be good but it still works for me.

How do I construct a syntax-only match-finder tool?

I am building an ASTMatcher-based tool that I would like to run over my sources:
int main(int argc, const char** argv) {
CommonOptionsParser OptionsParser(argc, argv, MyToolCategory);
ClangTool Tool(OptionsParser.getCompilations(),
OptionsParser.getSourcePathList());
MatchFinder Finder;
// Repeated calls to Finder.addMatcher(...);
Tool.run(newFrontendActionFactory(&Finder).get());
// Handle the results of the matching.
}
Running this over a source file that depends on other headers yields the following error:
~$ /path/to/my/tool /path/to/my/file.cpp --
/path/to/my/file.cpp:8:10: fatal error: 'string' file not found
#include <string>
^~~~~~~~
1 error generated.
Error while processing /path/to/my/file.cpp.
I do not want to include any other headers in this processing, lest my matchers find content in those headers that I do not want to handle.
I tried passing -fsyntax_only to the tool, but I get the same result as above:
~$ /path/to/my/tool /path/to/my/file.cpp -- -fsyntax-only
I noticed in the ASTMatcher tutorial that there is a clang::SyntaxOnlyAction. However, I have been unable to figure out how MatchFinder and SyntaxOnlyAction can be used in conjunction with one another. Likewise, I have been able to do an AST dump from the command line of the same file, no problem, so I know it's possible.
Is it possible to configure a MatchFinder-based tool to honor the syntax-only behavior?

Erlang C-Node erl_errno symbol not found error

I tried to use erl_errno as described in the erlang document: http://erlang.org/doc/man/erl_error.html#.
However, I'm getting a symbol not found problem during linking. I'm running on Mac and here's the how the program is linked:
g++ -L/usr/local/lib/erlang/lib/erl_interface-3.9.3/lib -o "roserl" ./src/driver.o ./src/erl_bridge.o -lei -lm -lerl_interface
I have already linked with libei and liberl_interface. What else is needed?
It is weird but you will have to do this in your header:
#ifndef _REENTRANT
#define _REENTRANT /* For some reason __erl_errno is undefined unless _REENTRANT is defined */
#endif
#include "erl_interface.h"
#include "ei.h"
This fixed the problem for me. Now I can use erl_errno.

win32-g++ error on for_each and lambda

I know this theme often turns up on stackoverflow, but the case here is different:
The following code compiles with MsVC++ 2013 but not with win32-g++. Is there any way of making it work with both compilers?
#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;
int main()
{
vector<int>my_vector;
for(int i=0; i < 6; i++)
my_vector.push_back(i);
for_each( my_vector.begin(), my_vector.end(), [ ](int n){cout<<n;});
return 0;
}
The errors reported are
||=== stdtest, Debug ===|
D:\dev\CplusPlus\stdtest\main.cpp||In function 'int main()':|
D:\dev\CplusPlus\stdtest\main.cpp|13|warning: lambda expressions only available with -std=c++11 or -std=gnu++11 [enabled by default]|
D:\dev\CplusPlus\stdtest\main.cpp|13|error: no matching function for call to 'for_each(std::vector<int>::iterator, std::vector<int>::iterator, main()::<lambda(int)>)'|
D:\dev\CplusPlus\stdtest\main.cpp|13|note: candidate is:|
c:\program files (x86)\codeblocks\mingw\bin\..\lib\gcc\mingw32\4.7.1\include\c++\bits\stl_algo.h|4436|note: template<class _IIter, class _Funct> _Funct std::for_each(_IIter, _IIter, _Funct)|
D:\dev\CplusPlus\stdtest\main.cpp|13|error: template argument for 'template<class _IIter, class _Funct> _Funct std::for_each(_IIter, _IIter, _Funct)' uses local type 'main()::<lambda(int)>'|
D:\dev\CplusPlus\stdtest\main.cpp|13|error: trying to instantiate 'template<class _IIter, class _Funct> _Funct std::for_each(_IIter, _IIter, _Funct)'|
||=== Build finished: 3 errors, 1 warnings (0 minutes, 0 seconds) ===|
I should add that I am assuming that the C++11 standard is turned on because "enabled by default". In case I am wrong, I am having a hard time finding out how to change the compiler switches from Code::Blocks.
it turns out that I was misled by the statement that -sdd=C++11 was "enabled by default".
I ended up finding a way of turning it on with the Project > Build Options> compiler settings
and then I clicked on the checkbox "have g++ follow the c++11 ISO C++ language settings" checkbox.
For those who are working with QtCreator add the following line to the project file:
QMAKE_CXXFLAGS += -std=c++11

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