<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <title>Specification for LLVM system code</title> </head> <body> <h1>Specification for LLVM system</h1> <h1><a name="index">Index</a></h1> <ul> <li><a href="#cvs">Checkout LLVM from CVS</a> <li><a href="#compilerun">Compile and Run</a> <li><a href="#layout">Program layout</a> <ol> <li><a href="#d&d">Depend and Debug directories</a></li> <li><a href="#include">llvm/include</a> <li><a href="#lib">llvm/lib</a> <li><a href="#test">llvm/test</a> <li><a href="#tools">llvm/tools</a> </ol> <li> <a href="#tutorial"> simple example for using tools</li> <li><a href="#links">Links</a> </ul> <h2><a name="tools">Checkout LLVM from CVS</a></h2> <p> <dl> <dt>cvs root directory:<dd> /home/vadve/vadve/Research/DynOpt/CVSRepository<br> <dt>project name:<dd> llvm </dl> For those who are not familar with cvs, there are two steps you should do:<br> <ol> <li> set CVSROOT. Add the following line into the .cshrc file in your home directory if you are using tcsh or csh:<br> <i>setenv CVSROOT /home/vadve/vadve/Research/DynOpt/CVSRepository</i> </li> <li> check out. Go to the directory you want to store LLVM, type <br> <i>cvs checkout llvm</i> </li> </ol> note: the c front-end implementation is not in cvs. If you want to use it, you can use excutable in Chris Lattner's directory<br> <dd><i>/home/vadve/lattner/cvs/gcc_install/bin/gcc</i><br> a brief usage of this gcc and other tools are introduced later. To read it now, click <a href="#tutorial">here</a>. <h2><a name="compilerun">Compile and Run</a></h2> There is a makefile in each directory. You can simple type <i>gmake</i> in the <b>~/llvm</b> directory to compile all the files or you can type <i>gmake</i> in the certain directory to compile all files and subdirectories in that directory.<br> You might want to add the the following directory into your path:<br> <dd><i>llvm/tools/Debug</i><br> so you can run tools in any directory. If you are using csh or tcsh, add <br> <dd><i>setenv PATH llvm/tools/Debug:${PATH}</i><br> at the end of the file .cshrc in your home directory. </dl> <h2><a name="layout">Program Layout</a></h2> Many useful infomation can be obtained from the LLVM doxygen tree available at <a href="http://llvm.cs.uiuc.edu/doxygen/"><i>http://llvm.cs.uiuc.edu/doxygen/ </i><br></a> The following is a brief introduction to code layout: <h3><a name="d&d">Depend and Debug directories</a></h3> Most directories contain these two directories. The depend directory contains dependance files which will be used during complilation. The debug directory contains object files, library files or executables after compilation. <h3><a name="include">llvm/include</a></h3> This directory contains common head files supporting the LLVM library. Specific head files which are only used by certain directory are place in that directory instead of here. <h3><a name="lib">llvm/lib</a></h3> This directory contains most important files of LLVM system. <br> <dl compact> <dt>llvm/lib/transforms/<dd> This directory contains files and directories for transforming one representation to another representation. <dt>llvm/lib/Target/<dd> This directory contains files and directories for target machine. The files under llvm/lib/Target describe the common property for any target machine. The directory llvm/lib/Target/Sparc describe the sparc machine specification. <br> <dt>llvm/lib/Analysis/<dd> This directory contains files and directories for doing all kinds of data and control analysis. <dt>llvm/lib/AsmParser/<dd> This directory contains files and directories for parsing the llvm assemly files. <dt>llvm/lib/ByteCode/<dd> This directory contains files and directories for reading and write LLVM bytecode. <dt>llvm/lib/CWrite/<dd> This directory contains files and directories for writing c files as output. <dt>llvm/lib/CodeGen/<dd> This directory contains files and directories for instruction selection, instruction scheduling and register allocation. <dt>llvm/lib/Reoptimizer<dd> This directory contains files and directories for all kinds of optimizations, e.g. dead code elimination, Loop Invariant Code Motion, etc. <dt>llvm/lib/Support/<dd> This directory contains some files and directories supporting the library, e.g. commandline processor and statistic reporter. <dt>llvm/lib/VMCore/<dd> This directory contains files and directories for implementing the virtual machine instruction set. </dl> <h3><a name="test">llvm/test</a></h3> This directory contains llvm assembly and other files to test the llvm library. <h3><a name="tools">llvm/tools</a></h3> <p> The <b>tools</b> directory contains many tools. You can always get help by typing <i>command_name --help </i>. The following is a brief introduction to each tool. <dl compact> <dt><i>analyze</i><dd> ??? <dt><i>as</i><dd>llvm .ll -> .bc assembler <br>The assembler transfroms the human readable assembly to llvm bytecode. <dt><i>dis</i><dd>llvm .bc -> .ll disassembler <br>The disassembler transfroms the llvm bytecode to human readable assembly. <dt><i>extract</i><dd> ??? <dt><i>gccas</i><dd>llvm .ll -> .bc assembler <br>The assembler transfroms the human readable assembly to llvm bytecode. <dt><i>gccld</i><dd>many llvm bytecode -> llvm bytecode + optimizations <br> gccld links many llvm bytecode files into one bytecode file and does some optimization. <dt><i>link</i><dd>many llvm bytecode -> llvm bytecode <br> <i>link</i> takes many llvm bytecode files and link them into one llvm bytecode file. <dt><i>llc</i><dd>llvm bytecode -> SPARC assembly <br> <i>llc</i> takes a llvm bytecode file and output a SPARC assembly file. <dt><i>lli</i><dd>llvm interpreter <br><i>lli</i> reads a llvm bytecode file and execute it. <dt><i>opt</i><dd>llvm .bc -> .bc modular optimizer <br> <i>opt</i> reads llvm bytecode and do certain optimization, then output llvm bytecode . </dl> <h2><a name="tutorial">tutorial for using tools</h2> <ul> <li>create a simple c file:<br> <pre> hello.c int main() { printf("hello world\n"); return 0; } </pre> </li> <li>compile the c file into a llvm bytecode file<br> <i>% alias llvmgcc /home/vadve/lattner/cvs/gcc_install/bin/gcc</i><br> <i>% llvmgcc hello.c </i><br> there will be two output files: <b>a.out</b> and <b>a.out.bc</b>. The file <b>a.out</b> is a shell script and <b>a.out.bc</b> is the llvm bytecode. You can run a.out to excute or directly call the interpreter: <br> % <i>lli a.out.bc</i><br> <li> dissembler and assembler <br> read llvm bytecode and output human readable llvm assembly<br> %<i>dis a.out.bc -o hello.ll</i><br> read human readable llvm assembly code and output llvm bytecode<br> %<i>as hello.ll -o hello.bc</i> </li> <li> compile to sparc assembly<br> <i>%llc hello.bc -o hello.s</i> </li> </ul> <h2><a name="links">Links</a></h2> <ul> <li><a href="http://llvm.cs.uiuc.edu/">LLVM homepage</a></li> <li><a href="http://tank.cs.uiuc.edu/doxygen/">LLVM doxygen tree</a></li> </ul> <hr> If you have any question, please send an email to <a href="mailto:lattner@uiuc.edu">Lattner Chris Arthur</a> or <a href="mailto:gshi1@uiuc.edu">Guochun Shi</a>. <p> <!-- Created: Mon Jul 1 02:29:02 CDT 2002 --> <!-- hhmts start --> Last modified: Wed Jul 17 17:55:16 CDT 2002 <!-- hhmts end --> </body> </html>