Add a *VERY INITIAL* machine code emitter class.  This is enough to take
this C function:
int foo(int X) { return X +1; }

and make objdump produce the following:

$ objdump -d t-llvm.o

t-llvm.o:     file format elf32-i386

Disassembly of section .text:

00000000 <.text>:
   0:   b8 01 00 00 00          mov    $0x1,%eax
   5:   03 44 24 04             add    0x4(%esp,1),%eax
   9:   c3                      ret


Anything using branches or refering to the constant pool or requiring
relocations will not work yet.

llvm-svn: 22375

characters from them.

llvm-svn: 22371

Add support for emitting external and .bss symbols.

llvm-svn: 22358

module to the ELF file.  Test it by adding support for emitting common
symbols.  This allows us to compile this:

%X = weak global int 0
%Y = weak global int 0
%Z = weak global int 0

to an elf file that 'readelf's this:

Symbol table '.symtab' contains 4 entries:
   Num:    Value  Size Type    Bind   Vis      Ndx Name
     0: 00000000     0 NOTYPE  LOCAL  DEFAULT  UND
     1: 00000004     4 OBJECT  GLOBAL DEFAULT  COM X
     2: 00000004     4 OBJECT  GLOBAL DEFAULT  COM Y
     3: 00000004     4 OBJECT  GLOBAL DEFAULT  COM Z

llvm-svn: 22343

For now, the elf writer is only capable of emitting an empty elf file, with
a section table and a section table string table.  This will be enhanced
in the future :)

llvm-svn: 22291