LLVM tutorial --system-libs does not exist - c++

I have been working through the Kaleidoscope tutorial for LLVM and have been having endless problems compiling it. In the following tutorial it appears that the flag "--system-libs" doesn't exist for llvm-config (it simply prints out a usage block). I have tried leaving it out but it seems like a rabbit hole of linker errors which leads me to believe I have just set up my development environment completely wrong. I have tried it both on OSX Yosemite and Ubuntu with similar results. The not found error can be resolved by adding -I [path to llvm] however this just exposes more errors making me think that is the wrong approach.
http://llvm.org/releases/3.6.0/docs/tutorial/LangImpl3.html
$make
#clang++ -g -v -L -std=c++11 -O3 toy.cpp -I/usr/include/llvm-3.5/ `llvm-config --cxxflags --ldflags --libs all` -o toy
clang++ -g -O3 toy.cpp `llvm-config --cxxflags --ldflags --system-libs --libs core` -o toy
usage: llvm-config <OPTION>... [<COMPONENT>...]
Get various configuration information needed to compile programs which use
LLVM. Typically called from 'configure' scripts. Examples:
llvm-config --cxxflags
llvm-config --ldflags
llvm-config --libs engine bcreader scalaropts
Options:
--version Print LLVM version.
--prefix Print the installation prefix.
--src-root Print the source root LLVM was built from.
--obj-root Print the object root used to build LLVM.
--bindir Directory containing LLVM executables.
--includedir Directory containing LLVM headers.
--libdir Directory containing LLVM libraries.
--cppflags C preprocessor flags for files that include LLVM headers.
--cflags C compiler flags for files that include LLVM headers.
--cxxflags C++ compiler flags for files that include LLVM headers.
--ldflags Print Linker flags.
--libs Libraries needed to link against LLVM components.
--libnames Bare library names for in-tree builds.
--libfiles Fully qualified library filenames for makefile depends.
--components List of all possible components.
--targets-built List of all targets currently built.
--host-target Target triple used to configure LLVM.
--build-mode Print build mode of LLVM tree (e.g. Debug or Release).
Typical components:
all All LLVM libraries (default).
engine Either a native JIT or a bitcode interpreter.
toy.cpp:1:10: fatal error: 'llvm/IR/Verifier.h' file not found
#include "llvm/IR/Verifier.h"
^
1 error generated.
make: *** [parser] Error 1

Turns out the version of llvm-config I am using is out of date. On Ubuntu I can just apt-get install llvm-config-3.6 and on OSX I can do a brew install homebrew/versions/llvm36. Finally use llvm-config-3.6 instead of just llvm-config.

Related

Building GDAL with all libraries static

I want to develop a small program that checks which polygons from a shapefile intersect a given rectangle. This program is to be used in a website (with PHP's exec() command). The problem is, my webserver cannot install GDAL, for reasons unknown to me. So I can't link to the shared libraries. Instead, I must link to static libraries, but these aren't given.
I've downloaded the GDAL source code from here (2.3.2 Latest Stable Release - September 2018), and followed the build instructions from here. Since I already have GDAL working on my Debian, and don't want to mess with it, I followed the "Install in non-root directory" instructions, with some adjusts from the last item in the "Some caveats" section:
cd /home/rodrigo/Downloads/gdal232/gdal-2.3.2
mkdir build
./configure --prefix=/home/rodrigo/Downloads/gdal232/gdal-2.3.2/build/ --without-ld-shared --disable-shared --enable-static
make
make install
export PATH=/home/rodrigo/Downloads/gdal232/gdal-2.3.2/build/bin:$PATH
export LD_LIBRARY_PATH=/home/rodrigo/Downloads/gdal232/gdal-2.3.2/build/lib:$LD_LIBRARY_PATH
export GDAL_DATA=/home/rodrigo/Downloads/gdal232/gdal-2.3.2/build/share/gdal
/usr/bin/gdalinfo --version
build/bin/gdalinfo --version
The first /usr/bin/gdalinfo --version gives 2.1.2 (the previous installed version). The second, build/bin/gdalinfo --version, gives 2.3.2 (the version just built).
By now, my program only uses the ogrsf_frmts.h header, which is in /usr/include/gdal/ or /home/rodrigo/Downloads/gdal232/gdal-2.3.2/build/include/ directory, depending on the build. There's no ogrsf_frmts.a file, but only a libgdal.a. Is this the file I should be linking against? If so, how? I've tried so far:
gcc geofragc.cpp -l:libgdal.a
gcc geofragc.cpp -Wl,-Bstatic -l:libgdal.a
gcc geofragc.cpp -Wl,-Bstatic -l:/home/rodrigo/Downloads/gdal232/gdal-2.3.2/build/lib/libgdal.a
gcc geofragc.cpp -Wl,-Bstatic -l/home/rodrigo/Downloads/gdal232/gdal-2.3.2/build/lib/libgdal.a
gcc geofragc.cpp /home/rodrigo/Downloads/gdal232/gdal-2.3.2/build/lib/libgdal.a
gcc geofragc.cpp -l/home/rodrigo/Downloads/gdal232/gdal-2.3.2/build/lib/libgdal.a
gcc geofragc.cpp -l:/home/rodrigo/Downloads/gdal232/gdal-2.3.2/build/lib/libgdal.a
but nothing works. What am I missing?
EDIT
The second trial (gcc geofragc.cpp -Wl,-Bstatic -l:libgdal.a) is giving the following error:
/usr/bin/ld: cannot find -lgcc_s
/usr/lib/gcc/x86_64-linux-gnu/6/../../../../lib/libgdal.a(gdalclientserver.o): In function `GDALServerSpawnAsync()':
(.text+0x1f5e): warning: Using 'getaddrinfo' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
/usr/bin/ld: cannot find -lgcc_s
collect2: error: ld returned 1 exit status
You can use the gdal-config program to get correct options for compilation and linking. This program is a part of the GDAL library and it has its own options:
hekto#ubuntu:~$ gdal-config --help
Usage: gdal-config [OPTIONS]
Options:
[--prefix[=DIR]]
[--libs]
[--dep-libs]
[--cflags]
[--datadir]
[--version]
[--ogr-enabled]
[--gnm-enabled]
[--formats]
You have to make sure this program is on your search path, or you can create an alias - for example:
alias gdal-config='/home/rodrigo/Downloads/gdal232/gdal-2.3.2/bin/gdal-config'
Now your compilation and linking command becomes the following one:
g++ `gdal-config --cflags` geofragc.cpp `gdal-config --libs` `gdal-config --dep-libs`
You have to use the g++ compiler to link with C++-built libraries.
Another option is to create a Makefile with these lines:
CXXFLAGS += ${shell gdal-config --cflags}
LDLIBS += ${shell gdal-config --libs}
LDLIBS += ${shell gdal-config --dep-libs}
geofragc: geofragc.cpp
and just call make with this Makefile.
I hope, it'll help.

'llvm/IR/Constants.h' file not found

I'm trying to make a compiler and I'm using llvm (C++ api) for intermediate and final code production. Though when trying to execute the command:
llvm.o: llvm.cpp llvm.h
$(CPP) llvm.cpp -c -$(FLAGS)
in my make file I'm getting the error:
In file included from llvm.cpp:6:
./opt.h:5:10: fatal error: 'llvm/IR/Constants.h' file not found
#include <llvm/IR/Constants.h>
^~~~~~~~~~~~~~~~~~~~~
1 error generated.
I'm using Mac Os (Sierra version 10.12.6) and I've installed llvm using brew (brew install llvm) so I can't understand how the library file can't be found.
Also my clang version:
bash-3.2$ clang --version
Apple LLVM version 9.0.0 (clang-900.0.37)
Target: x86_64-apple-darwin16.7.0
Thread model: posix
InstalledDir: /Library/Developer/CommandLineTools/usr/bin
I've googled it a lot but couldn't find anything that solve my problem, any help appreciated !!!.
What're your FLAGS? You would need to provide linker flags and header search flags.
The following could help you:
llvm.o: llvm.cpp llvm.h
$(CPP) llvm.cpp -c -$(FLAGS) `llvm-config --cxxflags --ldflags --libs`
Note that the --libs without any parameters will link your binary with all the LLVM libraries.
UPD:
On MacOS llvm-config and other tools are not added to the $PATH, because it would override system compiler and can screw your system in some way. You would need to use the full path, e.g. /usr/local/Cellar/llvm/3.9.0/bin/llvm-config. Make sure you use the right version here.
Also, make sure that your FLAGS are actually evaluated and not pasted to the command as is:
FLAGS=$(shell llvm-config --cxxflags --ldflags --libs)

Cross-Compiling wxWidgets code from Linux to Windows

I use Code::Blocks IDE with wxWidgets in Debian 8.9 Jessie (x86-64).
When I use the GNU GCC Compiler everything works fine thus compiling nice wxWidgets executable for Linux.
But I need to have my program working on Windows platforms so I have to do cross-compiling.
I have installed mingw32 and followed the cross-compiling instructions given
here.
I did my wxWidgets build configuration as follows:
./configure prefix=/usr/i686-w64-mingw32 --host=i686-w64-mingw32 --enable-unicode --build=`./config.guess` --disable-shared
This is so because the MinGW compiler I have is i686-w64-mingw32, located in the folder /usr/i686-w64-mingw32, and wxWidgets version is 3.1.
My compiler set-up in Code::Blocks should be correct because I managed to do cross-compiling for simple console applications and those run properly on Windows 10.0. But when it comes to wxWidgets applications there are several problems:
The compiler gives me the error (it happens when --static is added to Other compiler options in the build options for the project):
fatal error: wx/app.h: No such file or directory|
Now since wx directory in question is in the path /usr/i686-w64-mingw32/include/wx-3.1 I added this path to the search directories for the project (the build target only for the moment). This worked fine to proceed further.
My compiler settings are: wx-config --host=i686-w64-mingw32 --static --cflags
The compiler swears again (not surprised though :-)):
fatal error: wx/setup.h: No such file or directory|
Ok I've found this one in /usr/i686-w64-mingw32/lib/wx/include/i686-w64-mingw32-msw-unicode-static-3.1, so added this path to the compiler search directories.
The linker is swearing this time (creeping on my nerves):
for the build target:
undefined reference to `wxEntry(HINSTANCE__*, HINSTANCE__*, char*, int)'|
for the release target:
undefined reference to `wxAppConsoleBase::CheckBuildOptions(char const*, char const*)'|
My linker settings are wx-config --host=i686-w64-mingw32 --static --libs
I tried hard to fix this with several different build options for the wxWidgets library but with no effect on the result. So please, someone help!
I also noticed that running ./config.guess form the wxWidgets download directory gives me x86_64-unknown-linux-gnu. Thus this mean I should use x86_64-w64-mingw32 (I have this one installed in /usr/x86_64-w64-mingw32) compiler instead i686-w64-mingw32?
So the main issue is that the command wx-config --static --cflags is not recognized in Other compiler options and wx-config --static --libs is not recognized in Other linker options.
The problem persisted even though I added the path to wx-config file in the .bashrc file from the home directory, i.e. export PATH="$PATH:/usr/i686-w64-mingw32/bin". At that time I was able to run wx-config from the terminal at any location.
To solve it I've changed the options to /usr/i686-w64-mingw32/bin/wx-config --static --cflags in Other compiler options and /usr/i686-w64-mingw32/bin/wx-config --static --libs in Other linker options. This worked as a charm.
I've added the location of libstdc++-6.dll (simply found it with a search in the file manager) in Link libraries and the flags -static and -static-libgcc in Other linker options and finally did the testing with the minimal sample as Igor suggested. Just create new console application, add minimal.cpp file to it and all of the mentioned above.
The compiler did a Minimal.exe file that I have opened successfully with wine.
Note: All the include directories I mentioned in my question were in wx-config --cflags for the compiler and wx-config --libs for the linker, so no need to add them in search directories.

How to add script for generate flags into Xcode?

I'm learning llvm with its official tutorial. The problem I met is that if I use shell directly to compile c++ files to link with llvm libraries, it's very convenient to have llvm-config to generate the correct flags and paths for me. Like this one:
/usr/local/opt/llvm/bin/llvm-config --cxxflags --ldflags --system-libs --libs core
But I would like to use Xcode to debug my c++ code. So how can I add the script above to Xcode to generate the paths and flags?

LLVM header not found after apt-get install

I installed llvm and clang 3.9 along with all the other packages using the below command as given in LLVM Nightly packages link.
sudo apt-get install clang-3.9 clang-3.9-doc llvm-3.9 llvm-3.9-dev llvm-3.9-doc llvm-3.9-examples llvm-3.9-runtime clang-format-3.9 python-clang-3.9 libclang-common-3.9-dev libclang-3.9-dev libclang1-3.9 libclang1-3.9-dbg libllvm-3.9-ocaml-dev libllvm3.9 libllvm3.9-dbg lldb-3.9 lldb-3.9-dev liblldb-3.9-dbg
Then I tried to compile and run the sample lexer and parser for kaleidoscope language according to this tutorial.
However, I am not able to compile the given sample program, because I get the error:
clang++-3.9 -g -O3 toy.cpp
toy.cpp:1:10: fatal error: 'llvm/ADT/STLExtras.h' file not found
#include "llvm/ADT/STLExtras.h"
^
1 error generated.
I think this error is because LLVM was installed as llvm-3.9 and hence all the files were installed in directories ending with *-3.9. How can I fix this error without having to remove the installation and do a manual build install from the LLVM source?
That looks like a bug in the tutorial -- the code in toy.cpp used to be self-contained, but it now depends on an LLVM header (this is a recent change).
You can use the command provided in chapter 3 to build instead, i.e.:
clang++ -g -O3 toy.cpp `llvm-config --cxxflags --ldflags --system-libs --libs core` -o toy