[llvm-commits] [llvm] r79652 - in /llvm/trunk: include/llvm/MC/MCAssembler.h lib/MC/MCAssembler.cpp lib/MC/MCMachOStreamer.cpp test/MC/MachO/data.s

[Chris Lattner]

On Aug 21, 2009, at 11:29 AM, Daniel Dunbar wrote:
> URL: http://llvm.org/viewvc/llvm-project?rev=79652&view=rev
> Log:
> llvm-mc/Mach-O: Support byte and fill value emission.

> +++ llvm/trunk/include/llvm/MC/MCAssembler.h Fri Aug 21 13:29:01  
> 2009@@ -63,26 +275,44 @@
>   MCSectionData();
>   MCSectionData(const MCSection &Section, MCAssembler *A = 0);
>
>   const MCSection &getSection() const { return Section; }
>
>   unsigned getAlignment() const { return Alignment; }
>   void setAlignment(unsigned Value) { Alignment = Value; }
>
> +
> +  /// @name Section List Access
> +  /// @{
> +
> +  const FragmentListType &getFragmentList() const { return  
> Fragments; }
> +  FragmentListType &getFragmentList() { return Fragments; }
> +
> +  iterator begin() { return Fragments.begin(); }
> +  const_iterator begin() const { return Fragments.begin(); }

frag_begin/frag_size, etc please.


> +  unsigned getFileSize() const {
> +    assert(FileSize != ~UINT64_C(0) && "File size not set!");

You can just use "!= ~0ULL" which we do all over the code base.

>
> +/// WriteFileData - Write the \arg F data to the output file.
> +static void WriteFileData(raw_ostream &OS, const MCFragment &F,
> +                          MachObjectWriter &MOW) {
> +  uint64_t Start = OS.tell();
> +  (void) Start;
> +
> +  // FIXME: Embed in fragments instead?

I think it could make sense for this to be a virtual method on  
fragment.  I can see targets wanting to be able to define their own  
target-specific Fragment types, so making Fragment be "really virtual"  
and avoiding switch statements is probably best.

> void MCMachOStreamer::EmitValue(const MCValue &Value, unsigned Size) {
> -  llvm_unreachable("FIXME: Not yet implemented!");
> +  new MCFillFragment(Value, Size, 1, CurSectionData);

Silly optimization idea, if the fill size is small it might be better  
to append this to a data fragment if active

-Chris