I am trying to write a Lua binding for a C library with LuaJIT's C ffi, but encountered this problem.
LuaJIT doesn't print the line, but only with -mavx2 flag set.
Here are the steps to reproduce the issue:
Environment
CPU: Intel(R) Core(TM) i5 CPU M 560 # 2.67GHz
OS: Ubuntu 16.04, 64bit
GCC version : gcc (Ubuntu 5.4.0-6ubuntu1~16.04.9) 5.4.0 20160609
LuaJIT version: 2.0.4
Actually I ran this inside the fantastic ZeroBrane Studio (Latest version)
test.c
#include <stdint.h>
uint64_t aux(const uint64_t b)
{
return b & b;
}
void test(uint64_t state)
{
uint64_t b[64];
for (int i = 0; i < 64; i++)
{
b[i] = (state<<1) ^ state;
}
aux(b[0]);
}
Compiling to a shared library
gcc -W -Wall -Winline -g -fPIC -shared -O3 -o libtest.so test.c # without -mavx2
gcc -W -Wall -Winline -g -fPIC -shared -O3 -mavx2 -o libtest.so test.c # with -mavx2
Using the library in LuaJIT
test.lua
local ffi = require("ffi")
local L = ffi.load("./libtest.so")
ffi.cdef[[
void test(uint64_t);
]]
local s = ffi.new("uint64_t", 0);
print("Hello!")
L.test(s)
print("Hello!")
Output
Without -mavx2: hello!\nhello\n, as expected.
With -mavx2: hello!\n
Related
I am trying to porting lttng on xilinx mpsoc with linux OS, I have write a demo as same as lttng "Record user application events", it runs on Ubuntu perfectly
g++ -c -I. hello-tp.c
g++ -c hello.c
g++ -o hello hello-tp.o hello.o -llttng-ust -ldl
but when I compile it on arm linux platform I got errors:
aarch64-xilinx-linux-g++ -mcpu=cortex-a72.cortex-a53 -march=armv8-a+crc -fstack-protector-strong -D_FORTIFY_SOURCE=2 -Wformat -Wformat-security -Werror=format-security --sysroot=/home/david/project/zcu102/images/linux/sdk/sysroots/cortexa72-cortexa53-xilinx-linux -O2 -pipe -g -feliminate-unused-debug-types -c -I. hello-tp.c
In file included from hello-tp.c:4:
hello-tp.h:16:27: error: expected constructor, destructor, or type conversion before ‘(’ token
16 | LTTNG_UST_TRACEPOINT_EVENT(hello_world, my_first_tracepoint, LTTNG_ARGS, LTTNG_FIELDS)
| ^
make: *** [Makefile:14: hello-tp.o] Error 1
here is the code
hello-tp.h:
#undef LTTNG_UST_TRACEPOINT_PROVIDER
#define LTTNG_UST_TRACEPOINT_PROVIDER hello_world
#undef LTTNG_UST_TRACEPOINT_INCLUDE
#define LTTNG_UST_TRACEPOINT_INCLUDE "./hello-tp.h"
#if !defined(_HELLO_TP_H) || defined(LTTNG_UST_TRACEPOINT_HEADER_MULTI_READ)
#define _HELLO_TP_H
#include <lttng/tracepoint.h>
#define LTTNG_ARGS LTTNG_UST_TP_ARGS(int, my_integer_arg, char *, my_string_arg)
#define LTTNG_FIELDS LTTNG_UST_TP_FIELDS(lttng_ust_field_string(my_string_field, my_string_arg) lttng_ust_field_integer(int, my_integer_field, my_integer_arg))
LTTNG_UST_TRACEPOINT_EVENT(hello_world, my_first_tracepoint, LTTNG_ARGS, LTTNG_FIELDS)
#endif /* _HELLO_TP_H */
#include <lttng/tracepoint-event.h>
hello-tp.c
#define LTTNG_UST_TRACEPOINT_CREATE_PROBES
#define LTTNG_UST_TRACEPOINT_DEFINE
#include "hello-tp.h"
hello.c
#include <stdio.h>
#include "hello-tp.h"
int main(int argc, char *argv[])
{
unsigned int i;
puts("Hello, World!\nPress Enter to continue...");
/*
* The following getchar() call only exists for the purpose of this
* demonstration, to pause the application in order for you to have
* time to list its tracepoints. You don't need it otherwise.
*/
getchar();
/*
* An lttng_ust_tracepoint() call.
*
* Arguments, as defined in `hello-tp.h`:
*
* 1. Tracepoint provider name (required)
* 2. Tracepoint name (required)
* 3. `my_integer_arg` (first user-defined argument)
* 4. `my_string_arg` (second user-defined argument)
*
* Notice the tracepoint provider and tracepoint names are
* C identifiers, NOT strings: they're in fact parts of variables
* that the macros in `hello-tp.h` create.
*/
lttng_ust_tracepoint(hello_world, my_first_tracepoint, 23,
"hi there!");
for (i = 0; i < argc; i++) {
lttng_ust_tracepoint(hello_world, my_first_tracepoint,
i, argv[i]);
}
puts("Quitting now!");
lttng_ust_tracepoint(hello_world, my_first_tracepoint,
i * i, "i^2");
return 0;
}
Makefile
APP = hello
# Add any other object files to this list below
APP_OBJS = hello-tp.o hello.o
all: build
build: $(APP)
$(APP): $(APP_OBJS)
$(CXX) -o $# $(APP_OBJS) $(LDFLAGS) -llttng -ldl
hello-tp.o : hello-tp.c hello-tp.h
$(CXX) $(CXXFLAGS) -c -I. $<
hello.o : hello.c
$(CXX) $(CXXFLAGS) -c $<
clean:
rm -f $(APP) *.o
Is there anyone met such issue? I guess the problem is caused by complier but I don't find any clue...
I just ran into this problem. Check your LTTNG version. The 2.13 release (current) uses LTTNG_UST_TRACEPOINT_PROVIDER. However, older releases uses TRACEPOINT_PROVIDER. The prefix LTTNG_UST has been added all over the place. See https://lttng.org/man/3/lttng-ust/v2.13/#doc-_compatibility_with_previous_apis
Under mac os x with g++ from gcc-5.2 I am trying to do the following : create a dylib exporting a class defined by header tmp8bis_dylib.h and source tmp8bis_dylib.cpp, and then create another dylib out of a source file tmp8bis.cpp using and linking to the previous dylib. Header and sources are in the same directory. I compile as follows :
g++-5.2.0 -m32 -Wall -g -c ./tmp8bis_dylib.cpp
g++-5.2.0 -m32 -dynamiclib ./tmp8bis_dylib.o -o ./tmp8bis_dylib.dylib
g++-5.2.0 -m32 -Wall -g -c ./tmp8bis.cpp
g++-5.2.0 -m32 -dynamiclib ./tmp8bis.o -o ./tmp8bis.dylib
and get this :
Undefined symbols for architecture i386:
"complex::cmodule(double, double)", referenced from:
_mymodule in tmp8bis.o
"complex::complex(double, double)", referenced from:
_mymodule in tmp8bis.o
"complex::~complex()", referenced from:
_mymodule in tmp8bis.o
ld: symbol(s) not found for architecture i386
collect2: error: ld returned 1 exit status
make: *** [all] Error 1
Obviously, I tried to pass various include and library paths with -I and -L flags respectively, with the very same result... Any idea ?
Files are below :
For tmp8bis_dylib.h :
#ifndef TMP_8_BIS_DYLIB_H
#define TMP_8_BIS_DYLIB_H
class complex
{
public:
double real;
double imag;
public:
complex();
complex(double x);
complex(double x,double y);
double cmodule(double x, double y);
~complex();
};
#endif
For tmp8bis_dylib.cpp :
#include "./tmp8bis_dylib.h"
#include <math.h>
extern "C"
{
complex::complex()
{
real = 0.0 ;
imag = 0.0 ;
}
complex::complex(double x)
{
real = x ;
imag = 0.0 ;
}
complex::complex(double x,double y)
{
real = x ;
imag = y ;
}
double complex::cmodule(double x, double y)
{
double res = sqrt(x*x+y*y);
return res ;
}
complex::~complex()
{
}
}
For tmp8bis.cpp :
#include <math.h>
#include "./tmp8bis_dylib.h"
extern "C"
{
double mymodule(double x, double y)
{
complex z(x,y);
double ret = z.cmodule(x,y);
return ret;
}
}
Precision. -m32 is because I need 32 bits dylib because the final dylib will be plugged into excel 2011's (for mac) VBA, which is 32 bits.
EDIT. Following Brett Hale's comment about Apple's advises about dylibs, I added
#define EXPORT __attribute__((visibility("default")))
after the #include's from tmp8bis.cpp, and EXPORT's for all its member functions, and compiled as follows :
g++-5.2.0 -m32 -Wall -g -c ./tmp8bis_dylib.cpp
g++-5.2.0 -m32 -dynamiclib ./tmp8bis_dylib.o -fvisibility=hidden -o ./tmp8bis_dylib.dylib
did a sudo cp ./tmp8bis_dylib.dylib /opt/lib/libtmp8bis_dylib.dylib and then compiled :
g++-5.2.0 -m32 -Wall -g -c ./tmp8bis.cpp
g++-5.2.0 -m32 -dynamiclib ./tmp8bis.o -o ./tmp8bis.dylib -L/opt/lib
and got the same result as before... Nor did
g++-5.2.0 -m32 -dynamiclib ./tmp8bis.o -o ./tmp8bis.dylib -ltmp8bis_dylib.dylib
make my day.
Without resorting to #define EXPORT __attribute__((visibility("default"))) or any -fvisibility=hidden
g++-5.2.0 -m32 -Wall -fpic -g -c ./tmp8bis_dylib.cpp
g++-5.2.0 -m32 -shared ./tmp8bis_dylib.o -o ./libtmp8bis_dylib.dylib
g++-5.2.0 -m32 -Wall -g -c ./tmp8bis.cpp
g++-5.2.0 -m32 -shared ./tmp8bis.o -o ./tmp8bis.dylib -L. -ltmp8bis_dylib
finally worked. I did not managed to succeed without -fpic, naming libtmp8bis_dylib.dylib and using -ltmp8bis_dylib.
OS : OS X 10.8.1
QtCreator : 2.6.2
Command line is fine, but QtCreator fail to compile the codes.
#include <functional>
#include <iostream>
#include <memory>
#include <string>
#include <vector>
int main(int argc, const char * argv[])
{
std::vector<std::string> strs{"yahoo", "haha"};
for(auto const &data : strs){
std::cout<<data<<std::endl;
}
std::vector<std::string> strs2 = std::move(strs);
std::unique_ptr<int> A(new int(3));
std::cout<<*A<<std::endl;
return 0;
}
Command line :
clang++ -stdlib=libc++ -std=c++11 main.cpp -o test
Compiler setting of QtCreator
http://www.flickr.com/photos/92283971#N04/8453188038/in/photostream
Qt .pro file
TEMPLATE = app
CONFIG += console
CONFIG -= app_bundle
CONFIG -= qt
SOURCES += main.cpp
QMAKE_CXXFLAGS += -std=c++11
QMAKE_CXXFLAGS += -stdlib=libc++
Error message:
clang: error: invalid deployment target for -stdlib=libc++ (requires
OS X 10.7 or later) make: *** [main.o] Error 1
But my OS number is 10.8.1
TEMPLATE = app
CONFIG += console
CONFIG -= app_bundle
CONFIG -= qt
SOURCES += main.cpp
LIBS += -stdlib=libc++
QMAKE_CXXFLAGS += -stdlib=libc++
QMAKE_CXXFLAGS += -std=c++11
QMAKE_CXXFLAGS += -mmacosx-version-min=10.7
QMAKE_LFLAGS += -mmacosx-version-min=10.7
I can compile the codes by this .pro file
But there are warning when you play with Qt library
ld: warning: directory not found for option ‘-F/Users/yyyy/Qt5.0.1/5.0.1/clang_64/qtbase/lib’
After some research, I find out this is a bug of Qt5
It is ok if you ignore this warning message even it is annoying
This seemed to do the trick for me.
CONFIG += c++11
It correctly put -std=c++11 in the command line and I didn't get any compiler or linker errors.
Using Qt 5.2.
I have one .cu file that contains my cuda kernel, and a wrapper function that calls the kernel. I have a bunch of .c files as well, one of which contains the main function. One of these .c files calls the wrapper function from the .cu to invoke the kernel.
I compile these files as follows:
LIBS=-lcuda -lcudart
LIBDIR=-L/usr/local/cuda/lib64
CFLAGS = -g -c -Wall -Iinclude -Ioflib
NVCCFLAGS =-g -c -Iinclude -Ioflib
CFLAGSEXE =-g -O2 -Wall -Iinclude -Ioflib
CC=gcc
NVCC=nvcc
objects := $(patsubst oflib/%.c,oflib/%.o,$(wildcard oflib/*.c))
table-hash-gpu.o: table-hash.cu table-hash.h
$(NVCC) $(NVCCFLAGS) table-hash.cu -o table-hash-gpu.o
main: main.c $(objects) table-hash-gpu.o
$(CC) $(CFLAGSEXE) $(objects) table-hash-gpu.o -o udatapath udatapath.c $(LIBS) $(LIBDIR)
So far everything is fine. table-hash-gpu.cu calls a function from one of the .c files. When linking for main, I get the error that the function is not present. Can someone please tell me what is going on?
nvcc compiles both device and host code using the host C++ compiler, which implies name mangling. If you need to call a function compiled with a C compiler in C++, you must tell the C++ compiler that it uses C calling conventions. I presume that the errors you are seeing are analogous to this:
$ cat cfunc.c
float adder(float a, float b, float c)
{
return a + 2.f*b + 3.f*c;
}
$ cat cumain.cu
#include <cstdio>
float adder(float, float, float);
int main(void)
{
float result = adder(1.f, 2.f, 3.f);
printf("%f\n", result);
return 0;
}
$ gcc -m32 -c cfunc.c
$ nvcc -o app cumain.cu cfunc.o
Undefined symbols:
"adder(float, float, float)", referenced from:
_main in tmpxft_0000b928_00000000-13_cumain.o
ld: symbol(s) not found
collect2: ld returned 1 exit status
Here we have code compiled with nvcc (so the host C++ compiler) trying to call a C function and getting a link error, because the C++ code expects a mangled name for adder in the supplied object file. If the main is changed like this:
$ cat cumain.cu
#include <cstdio>
extern "C" float adder(float, float, float);
int main(void)
{
float result = adder(1.f, 2.f, 3.f);
printf("%f\n", result);
return 0;
}
$ nvcc -o app cumain.cu cfunc.o
$ ./app
14.000000
It works. Using extern "C" to qualify the declaration of the function to the C++ compiler, it will not use C++ mangling and linkage rules when referencing adder and the resulting code links correctly.
I tried to link my executable program with 2 static libraries using g++. The 2 static libraries have the same function name. I'm expecting a "multiple definition" linking error from the linker, but I did not received. Can anyone help to explain why is this so?
staticLibA.h
#ifndef _STATIC_LIBA_HEADER
#define _STATIC_LIBA_HEADER
int hello(void);
#endif
staticLibA.cpp
#include "staticLibA.h"
int hello(void)
{
printf("\nI'm in staticLibA\n");
return 0;
}
output:
g++ -c -Wall -fPIC -m32 -o staticLibA.o staticLibA.cpp
ar -cvq ../libstaticLibA.a staticLibA.o
a - staticLibA.o
staticLibB.h
#ifndef _STATIC_LIBB_HEADER
#define _STATIC_LIBB_HEADER
int hello(void);
#endif
staticLibB.cpp
#include "staticLibB.h"
int hello(void)
{
printf("\nI'm in staticLibB\n");
return 0;
}
output:
g++ -c -Wall -fPIC -m32 -o staticLibB.o staticLibB.cpp
ar -cvq ../libstaticLibB.a staticLibB.o
a - staticLibB.o
main.cpp
extern int hello(void);
int main(void)
{
hello();
return 0;
}
output:
g++ -c -o main.o main.cpp
g++ -o multipleLibsTest main.o -L. -lstaticLibA -lstaticLibB -lstaticLibC -ldl -lpthread -lrt
The linker does not look at staticLibB, because by the time staticLibA is linked, there are no unfulfilled dependencies.
That's an easy one. An object is only pulled out of a library if the symbol referenced hasn't already been defined. Only one of the hellos are pulled (from A). You'd get errors if you linked with the .o files.
When the linker tries to link main.o into multipleLibsTest and sees that hello() is unresolved, it starts searching the libraries in the order given on the command line. It will find the definition of hello() in staticLibA and will terminate the search.
It will not look in staticLibB or staticLibC at all.
If staticLibB.o contained another symbol not in staticLibA and that was pulled into the final executable, you then get a multiple definition of hello error, as individual .o files are pulled out of the library and two of them would have hello(). Reversing the order of staticLibA and staticLibB on the link command line would then make that error go away.