sparse LLVM backend (was Re: [rfc] built-in native compiler for Linux?)

(resent -- the mail monster apparently ate the first one)

Just to make this crazy thread even crazier, I have successfully gotten sparse to create a valid x86-64 object file from C source code (...which I then executed).

The attached patch adds a code generator backend to sparse, that generates LLVM bitcode. This bitcode can then be converted to ELF .o files using standard tools -- see instructions in the header of s2l.c.

Do I expect this to be used in the kernel? Not really. I'm just doing this for fun, to add a compiler backend to sparse. It was pretty easy to get integer and logical operations going.

The work is based on compile-i386; as it turns out, LLVM's bitcode can be made type-aware, so I wanted to see how things would turn out generating code at a higher level. Given the higher-level constructs, I didn't feel the need to bother with linearized form.

Caveats...

- don't stray too far from simple, integer types
- bitfields caused explosions, but you knew that anyway

Cheers all,

Jeff

 .gitignore |    2 
 Makefile   |    3 
 s2l-gen.c  | 2101 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 s2l.c      |   77 ++
 4 files changed, 2182 insertions(+), 1 deletion(-)

index a915ef3..eee93ec 100644
@@ -2,6 +2,7 @@
 *.o
 *.a
 *.so
+*.o.d
 
 # generated
 pre-process.h

@@ -20,6 +21,7 @@ example
 test-unssa
 ctags
 c2xml
+s2l
 
 # tags
 tags

index 15daba5..f993cf8 100644
@@ -35,7 +35,7 @@ INCLUDEDIR=$(PREFIX)/include
 PKGCONFIGDIR=$(LIBDIR)/pkgconfig
 
 PROGRAMS=test-lexing test-parsing obfuscate compile graph sparse \
-	 test-linearize example test-unssa test-dissect ctags
+	 test-linearize example test-unssa test-dissect ctags s2l
 INST_PROGRAMS=sparse cgcc
 INST_MAN1=sparse.1 cgcc.1
 

@@ -108,6 +108,7 @@ sparse.pc: sparse.pc.in
 
 
 compile_EXTRA_DEPS = compile-i386.o
+s2l_EXTRA_DEPS = s2l-gen.o
 
 PROG_LINK_CMD = $(QUIET_LINK)$(CC) $(LDFLAGS) -o $@ $^ $($@_EXTRA_OBJS) 
 

From: Jeff Garzik <[email protected]>
Date: Fri, 24 Apr 2009 22:06:42 -0400

The CC: line from hell was too long and thus getting rejected by vger