From 5907d407e3c39d630f1eca220d646733d03fdebd Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Mon, 14 Aug 2006 20:45:25 +0000 Subject: Update the example to work with llvm-gcc4. Fix validation errors. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@29670 91177308-0d34-0410-b5e6-96231b3b80d8 --- docs/GettingStarted.html | 91 +++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 86 insertions(+), 5 deletions(-) (limited to 'docs') diff --git a/docs/GettingStarted.html b/docs/GettingStarted.html index f75fbe2..ca0256d 100644 --- a/docs/GettingStarted.html +++ b/docs/GettingStarted.html @@ -305,17 +305,18 @@ up
  • No native code generation
  • Build is not complete: one or more tools don't link
  • The GCC-based C/C++ frontend does not build
    • -
  • The port is done using the MSYS shell. +
  • The port is done using the MSYS shell. Download and install bison (excl. M4.exe) and flex in that order. Build binutils-2.15 from source, -if necessary. Bison & flex can be also grabbed from GNUWin32 sf.net project
    • +if necessary. Bison & flex can be also grabbed from GNUWin32 sf.net +project.
  • Native code generation exists but is not complete.
    • -
  • Binutils up to post-2.17 has bug in bfd/cofflink.c +
  • Binutils up to post-2.17 has bug in bfd/cofflink.c preventing LLVM from building correctly. Several workarounds have been introduced into LLVM build system, but the bug can occur anytime in the - future. It's highly recommended to rebuild your current binutils with the + future. We highly recommend that you rebuild your current binutils with the patch from - Binutils bugzilla, if it's wasn't already applied.
    • + Binutils bugzilla, if it wasn't already applied. @@ -1489,6 +1490,86 @@ are code generators for parts of LLVM infrastructure.

    +

    This section gives an example of using LLVM. Since we are currently +transitioning from llvm-gcc3 to llvm-gcc4, we include examples for both. +

    +
    + + +
    Example with llvm-gcc4
    + +
    + +
      +
    1. First, create a simple C file, name it 'hello.c': + 
      +   #include <stdio.h>
+   int main() {
+     printf("hello world\n");
+     return 0;
+   }
+
      2. + +

    2. Next, compile the C file into a native executable:

      + +

      % llvm-gcc hello.c -o hello

      + +

      Note that llvm-gcc works just like GCC by default. The standard -S and + -c arguments work as usual (producing a native .s or .o file, + respectively).

      + +

    3. Next, compile the C file into a LLVM bytecode file:

      +

      % llvm-gcc -O3 -emit-llvm hello.c -c -o hello.bc

      + +

      The -emit-llvm option can be used with the -S or -c options to emit an + LLVM ".ll" or ".bc" file (respectively) for the code. This allows you + to use the standard LLVM tools on + the bytecode file.

      + +

      Unlike llvm-gcc3, llvm-gcc4 correctly responds to -O[0123] arguments. +

      4. + +

    4. Run the program in both forms. To run the program, use:

      + +

      % ./hello

      + +

      and

      + +

      % lli hello.bc

      5. + +

      The second examples shows how to invoke the LLVM JIT, lli.

      + +

    5. Use the llvm-dis utility to take a look at the LLVM assembly + code:

      + +

      % llvm-dis < hello.bc | less

      6. + +

    6. Compile the program to native assembly using the LLC code + generator:

      + +

      % llc hello.bc -o hello.s

      + +

    7. Assemble the native assembly language file into a program:

      + +

      Solaris:% /opt/SUNWspro/bin/cc -xarch=v9 hello.s -o hello.native

      +

      Others:% gcc hello.s -o hello.native

      + +

    8. Execute the native code program:

      + +

      % ./hello.native

      9. + +

      Note that using llvm-gcc to compile directly to native code (i.e. when + the -emit-llvm option is not present) does steps 6/7/8 for you.

      + +
    + +
    + + +
    Example with llvm-gcc3
    + +
    1. First, create a simple C file, name it 'hello.c': -- cgit v1.1