diff --git a/clang/www/get_started.html b/clang/www/get_started.html index cd2c84a60068..47909aba63f0 100644 --- a/clang/www/get_started.html +++ b/clang/www/get_started.html @@ -1,216 +1,216 @@ - - - - - Clang - Getting Started - - - - - - - -
- -

Getting Started: Building and Running Clang

- - -

This page gives you the shortest path to checking out clang and demos a few -options. This should get you up and running with the minimum of muss and fuss. -If you like what you see, please consider getting -involved with the clang community.

- - -

A word of warning

- -

While this work aims to provide a fully functional C/C++/ObjC front-end, it -is still very early work and is under heavy development. In particular, -there is no real C++ support yet (this is obviously a big project), and C/ObjC -support is still missing some features. Some of the more notable missing pieces -of C support are:

- -
    -
  1. The semantic analyzer does not produce all of the warnings and errors it - should.
    2. -
  2. The LLVM code generator is still missing important features. clang is not - ready to be used as a general purpose C code generator yet, but if you - hit problems and report them to cfe-dev, we'll fix them :).
    3. -
  3. We don't consider the API to be stable yet, and reserve the right to - change fundamental things.
    4. -
- -

Our plan is to continue chipping away at these issues until C works really -well, but we'd love help from other interested contributors. We expect C to be -in good shape by mid to late 2008.

- -

Building clang / working with the code

- -

If you would like to check out and build the project, the current scheme -is:

- -
    -
  1. Checkout - and build LLVM from SVN head:
    2. - - -
  2. Checkout clang:
    3. - -
  3. Non-mac users: Paths to system header files are currently hard coded - into clang; as a result, if clang can't find your system headers, - please follow these instructions:
    4. - - - -
  4. Build clang:
    5. - - -
  5. Try it out (assuming you add llvm/Debug/bin to your path):
    6. - -
- -

Note that the C front-end uses LLVM, but does not depend on - llvm-gcc. If you encounter problems with building clang, make - sure you have the latest SVN version of LLVM. LLVM contains - support libraries for clang that will be updated as well as - development on clang progresses.

- -

Examples of using clang

- -

The clang driver takes a lot of GCC compatible options, which you can see -with 'clang --help'. Here are a few examples:

- - -
-$ cat ~/t.c
-typedef float V __attribute__((vector_size(16)));
-V foo(V a, V b) { return a+b*a; }
-
- - -

Preprocessing:

- -
-$ clang ~/t.c -E
-# 1 "/Users/sabre/t.c" 1
-
-typedef float V __attribute__((vector_size(16)));
-
-V foo(V a, V b) { return a+b*a; }
-
- - -

Type checking:

- -
-$ clang -fsyntax-only ~/t.c
-
- - -

GCC options:

- -
-$ clang -fsyntax-only ~/t.c -pedantic
-/Users/sabre/t.c:2:17: warning: extension used
-typedef float V __attribute__((vector_size(16)));
-                ^
-1 diagnostic generated.
-
- - -

Pretty printing from the AST:

- -
-$ clang ~/t.c -ast-print
-typedef float V __attribute__(( vector_size(16) ));
-V foo(V a, V b) {
-   return a + b * a;
-}
-
- - -

Code generation with LLVM:

- -
-$ clang ~/t.c -emit-llvm | llvm-as | opt -std-compile-opts | llvm-dis
-define <4 x float> @foo(<4 x float> %a, <4 x float> %b) {
-entry:
-         %mul = mul <4 x float> %b, %a
-         %add = add <4 x float> %mul, %a
-         ret <4 x float> %add
-}
-$ clang ~/t.c -emit-llvm | llvm-as | opt -std-compile-opts | llc -march=ppc32 -mcpu=g5
-..
-_foo:
-         vmaddfp v2, v3, v2, v2
-         blr
-$ clang ~/t.c -emit-llvm | llvm-as | opt -std-compile-opts | llc -march=x86 -mcpu=yonah
-..
-_foo:
-         mulps %xmm0, %xmm1
-         addps %xmm0, %xmm1
-         movaps %xmm1, %xmm0
-         ret
-
- -

GCC "Emulation" Driver

- -While the clang executable is a compiler driver that can perform code -generation, program analysis, and other actions, it is not designed to be a -drop-in replacement for GCC's cc. There is interest in developing such -a driver for clang, but in the interim the clang source tree includes a Python -script ccc in the utils subdirectory that provides some of -this functionality (the script is intended to be used where GCC's cc -could be used). It is currently a work in progress, and eventually will likely -be replaced by a more complete driver. - -

Example use:

- -
-$ ccc t.c
-clang -emit-llvm-bc -o t.o -U__GNUC__ t.c
-llvm-ld -native -o a.out t.o
-$ ls
-a.out a.out.bc t.c t.o
-
- - - - -
- - + + + + + Clang - Getting Started + + + + + + + +
+ +

Getting Started: Building and Running Clang

+ + +

This page gives you the shortest path to checking out clang and demos a few +options. This should get you up and running with the minimum of muss and fuss. +If you like what you see, please consider getting +involved with the clang community.

+ + +

A word of warning

+ +

While this work aims to provide a fully functional C/C++/ObjC front-end, it +is still very early work and is under heavy development. In particular, +there is no real C++ support yet (this is obviously a big project), and C/ObjC +support is still missing some features. Some of the more notable missing pieces +of C support are:

+ +
    +
  1. The semantic analyzer does not produce all of the warnings and errors it + should.
    2. +
  2. The LLVM code generator is still missing important features. clang is not + ready to be used as a general purpose C code generator yet, but if you + hit problems and report them to cfe-dev, we'll fix them :).
    3. +
  3. We don't consider the API to be stable yet, and reserve the right to + change fundamental things.
    4. +
+ +

Our plan is to continue chipping away at these issues until C works really +well, but we'd love help from other interested contributors. We expect C to be +in good shape by mid to late 2008.

+ +

Building clang / working with the code

+ +

If you would like to check out and build the project, the current scheme +is:

+ +
    +
  1. Checkout + and build LLVM from SVN head:
    2. + + +
  2. Checkout clang:
    3. + +
  3. Non-mac users: Paths to system header files are currently hard coded + into clang; as a result, if clang can't find your system headers, + please follow these instructions:
    4. + + + +
  4. Build clang:
    5. + + +
  5. Try it out (assuming you add llvm/Debug/bin to your path):
    6. + +
+ +

Note that the C front-end uses LLVM, but does not depend on + llvm-gcc. If you encounter problems with building clang, make + sure you have the latest SVN version of LLVM. LLVM contains + support libraries for clang that will be updated as well as + development on clang progresses.

+ +

Examples of using clang

+ +

The clang driver takes a lot of GCC compatible options, which you can see +with 'clang --help'. Here are a few examples:

+ + +
+$ cat ~/t.c
+typedef float V __attribute__((vector_size(16)));
+V foo(V a, V b) { return a+b*a; }
+
+ + +

Preprocessing:

+ +
+$ clang ~/t.c -E
+# 1 "/Users/sabre/t.c" 1
+
+typedef float V __attribute__((vector_size(16)));
+
+V foo(V a, V b) { return a+b*a; }
+
+ + +

Type checking:

+ +
+$ clang -fsyntax-only ~/t.c
+
+ + +

GCC options:

+ +
+$ clang -fsyntax-only ~/t.c -pedantic
+/Users/sabre/t.c:2:17: warning: extension used
+typedef float V __attribute__((vector_size(16)));
+                ^
+1 diagnostic generated.
+
+ + +

Pretty printing from the AST:

+ +
+$ clang ~/t.c -ast-print
+typedef float V __attribute__(( vector_size(16) ));
+V foo(V a, V b) {
+   return a + b * a;
+}
+
+ + +

Code generation with LLVM:

+ +
+$ clang ~/t.c -emit-llvm | llvm-as | opt -std-compile-opts | llvm-dis
+define <4 x float> @foo(<4 x float> %a, <4 x float> %b) {
+entry:
+         %mul = mul <4 x float> %b, %a
+         %add = add <4 x float> %mul, %a
+         ret <4 x float> %add
+}
+$ clang ~/t.c -emit-llvm | llvm-as | opt -std-compile-opts | llc -march=ppc32 -mcpu=g5
+..
+_foo:
+         vmaddfp v2, v3, v2, v2
+         blr
+$ clang ~/t.c -emit-llvm | llvm-as | opt -std-compile-opts | llc -march=x86 -mcpu=yonah
+..
+_foo:
+         mulps %xmm0, %xmm1
+         addps %xmm0, %xmm1
+         movaps %xmm1, %xmm0
+         ret
+
+ +

GCC "Emulation" Driver

+ +While the clang executable is a compiler driver that can perform code +generation, program analysis, and other actions, it is not designed to be a +drop-in replacement for GCC's cc. There is interest in developing such +a driver for clang, but in the interim the clang source tree includes a Python +script ccc in the utils subdirectory that provides some of +this functionality (the script is intended to be used where GCC's cc +could be used). It is currently a work in progress, and eventually will likely +be replaced by a more complete driver. + +

Example use:

+ +
+$ ccc t.c
+clang -emit-llvm-bc -o t.o -U__GNUC__ t.c
+llvm-ld -native -o a.out t.o
+$ ls
+a.out a.out.bc t.c t.o
+
+ + + + +
+ +