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The MicroC compiler Coded in OCaml, this takes a highly stripped-down subset of C (ints, bools, and void types, arithmetic, if-else, for, and while statements, and user-defined functions) and compiles it into LLVM IR. It needs the OCaml llvm library, which is most easily installed through opam. Install LLVM and its development libraries, the m4 macro preprocessor, and opam, then use opam to install llvm. The version of the OCaml llvm library should match the version of the LLVM system installed on your system. In addition to print, which calls the C library function printf(), this gratuitiously includes a primitive function "printbig," which prints large ASCII-encoded characters. The stock C compiler compiles printbig.o. testall.sh runs the microc executable on each testcase (.mc file) to produce a .ll file, invokes "llc" (the LLVM compiler) to produce a .s (assembly) file, then invokes "cc" (the stock C compiler) to assemble the .s file, link in printbig.o, and generate an executable. See testall.sh for details. ------------------------------ Installation under Ubuntu 15.10 LLVM 3.6 is the default under 15.10, so we ask for a matching version of the OCaml library. sudo apt-get install -y ocaml m4 llvm opam opam init opam install llvm.3.6 ocamlfind eval `opam config env` make ./testall.sh ------------------------------ Installation under Ubuntu 14.04 The default LLVM package is 3.4, so we install the matching OCaml library using opam. The default version of opam under 14.04 is too old; we need to use a newer package. sudo apt-get install m4 llvm software-properties-common sudo add-apt-repository --yes ppa:avsm/ppa sudo apt-get update -qq sudo apt-get install -y opam opam init eval `opam config env` opam install llvm.3.4 ocamlfind ------------------------------ Installation under OS X 1. Install Homebrew: ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)" 2. Verify Homebrew is installed correctly: brew doctor 3. Install opam: brew install opam 4. Set up opam: opam init 5. Install llvm: brew install llvm Take note of where brew places the llvm executables. It will show you the path to them under the CAVEATS section of the post-install terminal output. For me, they were in /usr/local/opt/llvm/bin. Also take note of the llvm version installed. For me, it was 3.6.2. 6. Have opam set up your enviroment: eval `opam config env` 7. Install the OCaml llvm library: opam install llvm.3.6 Ensure that the version of llvm you install here matches the version you installed via brew. Brew installed llvm version 3.6.2, so I install llvm.3.6 with opam. IF YOU HAVE PROBLEMS ON THIS STEP, it's probably because you are missing some external dependencies. Ensure that libffi is installed on your machine. It can be installed with brew install libffi If, after this, opam install llvm.3.6 is still not working, try running opam list --external --required-by=llvm.3.6 This will list all of the external dependencies required by llvm.3.6. Install all the dependencies listed by this command. IF THE PREVIOUS STEPS DO NOT SOLVE THE ISSUE, it may be a problem with using your system's default version of llvm. Install a different version of llvm and opam install llvm with that version by running: brew install homebrew/versions/llvm37 opam install llvm.3.7 Where the number at the end of both commands is a version different from the one your system currently has. 8. Create a symbolic link to the lli command: sudo ln -s /usr/local/opt/llvm/bin/lli /usr/bin/lli Create the symlink from wherever brew installs the llvm executables and place it in your bin. From step 5, I know that brew installed the lli executable in the folder, /usr/local/opt/llvm/bin/, so this is where I symlink to. Brew might install the lli executables in a different location for you, so make sure you symlink to the right directory. IF YOU GET OPERATION NOT PERMITTED ERROR, then this is probably a result of OSX's System Integrity Protection. One way to get around this is to reboot your machine into recovery mode (by holding cmd-r when restarting). Open a terminal from recovery mode by going to Utilities -> Terminal, and enter the following commands: csrutil disable reboot After your machine has restarted, try the `ln....` command again, and it should succeed. IMPORTANT: the prevous step disables System Integrity Protection, which can leave your machine vulnerable. It's highly advisable to reenable System Integrity Protection when you are done by rebooting your machine into recovery mode and entering the following command in the terminal: csrutil enable reboot Another solution is to update your path, e.g., export PATH=$PATH:/usr/local/opt/llvm/bin A third solution is to modify the definition of LLI in testall.sh to point to the absolute path, e.g., LLI="/usr/local/opt/llvm/bin/lli" 9. To run and test, navigate to the MicroC folder. Once there, run make ; ./testall.sh MicroC should build without any complaints and all tests should pass. IF RUNNING ./testall.sh FAILS ON SOME TESTS, check to make sure you have symlinked the correct executable from your llvm installation. For example, if the executable is named lli-[version], then the previous step should have looked something like: sudo ln -s /usr/local/opt/llvm/bin/lli-3.7 /usr/bin/lli As before, you may also modify the path to lli in testall.sh ------------------------------ To run and test: $ make ocamlbuild -use-ocamlfind -pkgs llvm,llvm.analysis -cflags -w,+a-4 microc.native Finished, 22 targets (0 cached) in 00:00:01. cc -c -o printbig.o printbig.c $ ./testall.sh test-arith1...OK test-arith2...OK test-arith3...OK test-fib...OK ... fail-while1...OK fail-while2...OK
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MicroC example compiler for Stephen Edward's PLT class
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