What is the equivalent flag of /MAP in Clang to generate .map file?
This would be the closest that I can think of for clang and the linker map file
-Wl,-map,output.map
Related
I am working on LLVM obfuscation project. I have written a llvm pass(lets say flow flattening pass) which i am running on source (test.c) with following command:
clang -emit-llvm test.c -c -o test.bc
opt -load ../../.. LLVMFlattening.so -fla <test.bc>/dev/null
But i have seen that in O-LLVM project they achieved same thing using:
clang -emit-llvm test.c -c -o test.bc -mllvm -fla
Can someone tell me what is -mllvm here and how this changed to a simple command?
-mllvm means Additional arguments to forward to LLVM's option processing. Therefore -mllvm -fla will pass -fla to the LLVM's option processing.
Clang and LLVM could run seperately. If you want clang to run llvm, and also have some options which you want llvm to aware. -mllvm is what you need.
Defautly, LLVM does not turn on all the transformation passes. With -fla, LLVM will turn on the pass registered with command line argument fla by call function RegisterPass<typename passName>.
In your command line, opt's -load option is used to load plugin. If you want to use the simple command line as expect. Your pass need to be linked into the opt binary. This could be done in the following two ways:
(Without modify the existing LLVM source tree): Add your only pass's source by adding CMakeLists.txt mentioned in this link
Directly copy your pass source code folder into <LLVM root>/lib/Transform directory. And modify the <LLVM root>/lib/Transform/CMakeLists.txt, add add_subdirectory(<pass name>) line just like others.
I'm working on O-LLVM rencently, and came into the same problem. Here is my solution:
1.add static cl::opt<bool> YOUR_FLA("fla", cl::init(false),"info...") to PassManagerBuilder.cpp
2.add function Pass *createYOUR_FLA(bool flag) in your obfuscation pass source code
3.add MPM.add(createYOUR_FLA(YOUR_FLA)); to function populateModulePassManager in PassManagerBuilder.cpp
The solution above works with my simple pass.
I am trying to get exploded graph from one of the debug checkers called
debug.ViewExplodedGraph.
So I run command
clang -cc1 -analyze -analyzer-checker=debug.ViewExplodedGraph someprogram.c
It run successfully, but graph file no where to be found .
Where can we see the generated file?
I guess you should build the clang yourself. Then use the debug mode 'clang', call the command. The system clang is in release mode.
I use the system clang, it outputs nothing. But I use the clang that I build, it output something.
➜ bin ./clang -cc1 -analyze -analyzer-checker=debug.ViewExplodedGraph ~/Desktop/clang_test/test.c
Writing '/var/folders/_6/5wkxc9p92t94vdh0kyq2qyh40000gn/T/ExprEngine-9e6797.dot'... done.
Trying 'open' program... Remember to erase graph file: /var/folders/_6/5wkxc9p92t94vdh0kyq2qyh40000gn/T/ExprEngine-9e6797.dot
Warning: viewing graph requires assertions
➜ bin clang -cc1 -analyze -analyzer-checker=debug.ViewExplodedGraph ~/Desktop/clang_test/test.c
Warning: viewing graph requires assertions
cd to T folder
➜ T dot -Tsvg ExprEngine-9e6797.dot -o ~/Desktop/test.svg
then use chrome open test.svg
clang has an option, -x, which can be used to specify the language of subsequent source files passed to it. This caused problems when used like this:
clang -x c++ one.cc a.o b.o c.o
clang will try to interpret the object files a.o, b.o, c.o as source code.
Is there a way to cancel the effect of the -x option so I can pass object files on the same command line?
clang -x c++ one.cc SOMEOPTION a.o b.o c.o
What should SOMEOPTION be to allow clang to interpret the .o files as object files?
I need to use this convoluted command line because I am using a system that calls the compiler automatically to compile some code it generates and there are limits to how much it can be hacked.
could you put the arguments the other way 'round
clang a.o b.o c.o -x c++ one.cc
or compile each file and then link them in a later run
clang -x c++ one.cc -o one.cc.o
clang a.o b.o c.o one.cc.o
This is how in my experience it is actualy used.
I am trying to get hold on Clang. So, I would like to view the AST generated by Clang after parsing the given program. Is it possible to dump AST in .dot or .viz format? Is there any tool out there?
The method with -cc1 invocation will have problem with includes and recognizing C++.
For full-featured parsing, use:
clang -Xclang -ast-dump file.cpp
Clang supports showing the AST with Graphviz's dotty -- you can grab the temporary .dot file generated (name is printed out) to get the graph source.
clang -cc1 -ast-view your_file.c
You can also print to the command line with:
clang -cc1 -ast-dump your_file.c
or:
clang -cc1 -ast-print your_file.c
or in 3.3:
clang -cc1 -ast-dump-xml your_file.c
but this was removed later as pointed by Lukas Kubanek in the comment.
For viewing the AST
clang-check -ast-dump filename.c
For to view the specific functions in a program
clang-check -ast-dump -ast-dump-filter=function_name filename.c
I am using following:
clang my_file.h -I. -Xclang -ast-dump -fsyntax-only -fno-color-diagnostics -Wno-visibility
IMHO This is more suitable for machine parsing.
When using the default qmake compiler (via the SOURCES variable), I can use precompiled headers like so:
CONFIG += precompile_header
PRECOMPILED_HEADER = stable.h
SOURCES = main.c
However, I'd like to use a custom compiler (via QMAKE_EXTRA_COMPILERS). I tried this:
CONFIG += precompile_header
PRECOMPILED_HEADER = stable.h
MY_SOURCES = main.c
my.input = MY_SOURCES
my.output = ${QMAKE_FILE_IN_BASE}.o
my.commands = clang $$QMAKE_CFLAGS_USE_PRECOMPILE -c ${QMAKE_FILE_IN} -o ${QMAKE_FILE_OUT}
QMAKE_EXTRA_COMPILERS += my
...and the precompiled headers are built, but my custom compiler fails because QMAKE_CFLAGS_USE_PRECOMPILE doesn't contain the path to the precompiled header. (It is defined as -Xclang -include-pch -Xclang ${QMAKE_PCH_OUTPUT}, and apparently ${QMAKE_PCH_OUTPUT} is empty.)
How can I get the name of the generated precompiled header, so I can pass it as a parameter to my custom compiler?
Looking at the qmake source code, precompiled header handling seems to be hardcoded in UnixMakefileGenerator::init() to only work for the built-in C, CXX, OBJC, and OBJCXX compilers.
QMAKE_PCH_OUTPUT, for GCC and Clang-style precompiled headers, is constructed by combining PRECOMPILED_DIR, TARGET, one of c/c++/objective-c/objective-c++, and QMAKE_PCH_OUTPUT_EXT. So, in the question's second example, the following command line should work:
my.commands = clang -Xclang -include-pch -Xclang $$TARGET/c$$QMAKE_PCH_OUTPUT_EXT -c ${QMAKE_FILE_IN} -o ${QMAKE_FILE_OUT}