[cfe-dev] Getting started with clang

[Robert Wuest]

Hi,

I'm just getting started with clang and having some problems.  I'm 
trying to build a compiler to run on x8_64 and gen code for the 
powerpc.  My goal is to make some changes to the ppc code generator, but 
I'm not off to a very good start.

I have the latest source tree of llvm and clang from subversion and 
followed the build instructions.  This definitely produces a working 
native compiler as seen here:

$ clang hello.c
$ ./a.out
Hello, world

However, when I try the '-arch ppc' option, it still only produces 
x86_64 code:

$ rm a.out
$ clang -arch ppc hello.c
clang: warning: argument unused during compilation: '-arch ppc'
$ ./a.out
Hello, world

I am also seeing different output than that shown in the  
DriverInternals.html document that comes with clang.  In the "Driver 
Stages" section, there is an example I followed and get very different 
result from the doc:

Trying to get identical output, I broke hello world into 2 source files. 
It's trivial source; main() just calls hello() in f_hello.c. I know they 
compile:

$ rm a.out
[rwuest at garion hello]$ clang main.c f_hello.c
[rwuest at garion hello]$ ./a.out
Hello, world

However, the print-phase option with arch statements has no "bind-arch 
in the output (as indicated in the DriverInternals.html doc):

$  clang -ccc-print-phases -c -arch i386 -arch x86_64 main.c f_hello.c
0: input, "main.c", c
1: preprocessor, {0}, cpp-output
2: compiler, {1}, assembler
3: assembler, {2}, object
4: input, "f_hello.c", c
5: preprocessor, {4}, cpp-output
6: compiler, {5}, assembler
7: assembler, {6}, object


Have I missed something?

Robert