Produce new-style Cmm from the Cmm parser

The main change here is that the Cmm parser now allows high-level cmm
code with argument-passing and function calls.  For example:

foo ( gcptr a, bits32 b )
{
  if (b > 0) {
     // we can make tail calls passing arguments:
     jump stg_ap_0_fast(a);
  }

  return (x,y);
}

More details on the new cmm syntax are in Note [Syntax of .cmm files]
in CmmParse.y.

The old syntax is still more-or-less supported for those occasional
code fragments that really need to explicitly manipulate the stack.
However there are a couple of differences: it is now obligatory to
give a list of live GlobalRegs on every jump, e.g.

  jump %ENTRY_CODE(Sp(0)) [R1];

Again, more details in Note [Syntax of .cmm files].

I have rewritten most of the .cmm files in the RTS into the new
syntax, except for AutoApply.cmm which is generated by the genapply
program: this file could be generated in the new syntax instead and
would probably be better off for it, but I ran out of enthusiasm.

Some other changes in this batch:

 - The PrimOp calling convention is gone, primops now use the ordinary
   NativeNodeCall convention.  This means that primops and "foreign
   import prim" code must be written in high-level cmm, but they can
   now take more than 10 arguments.

 - CmmSink now does constant-folding (should fix #7219)

 - .cmm files now go through the cmmPipeline, and as a result we
   generate better code in many cases.  All the object files generated
   for the RTS .cmm files are now smaller.  Performance should be
   better too, but I haven't measured it yet.

 - RET_DYN frames are removed from the RTS, lots of code goes away

 - we now have some more canned GC points to cover unboxed-tuples with
   2-4 pointers, which will reduce code size a little.

1 files changed, 3 insertions, 3 deletions

diff --git a/compiler/codeGen/StgCmmGran.hs b/compiler/codeGen/StgCmmGran.hs
index 2abca3fe16..fe00d7c384 100644
--- a/compiler/codeGen/StgCmmGran.hs
+++ b/compiler/codeGen/StgCmmGran.hs
@@ -53,7 +53,7 @@ staticGranHdr = []
 doGranAllocate :: CmmExpr -> Code
 -- macro DO_GRAN_ALLOCATE
 doGranAllocate hp
-  | not opt_GranMacros = nopC
+  | not opt_GranMacros = return ()
   | otherwise          = panic "doGranAllocate"
 
 
@@ -75,7 +75,7 @@ granFetchAndReschedule regs node_reqd
   = do { fetch
        ; reschedule liveness node_reqd }
   | otherwise
-  = nopC
+  = return ()
   where
     liveness = mkRegLiveness regs 0 0
 
@@ -109,7 +109,7 @@ granYield :: [(Id,GlobalReg)]   -- Live registers
 
 granYield regs node_reqd
   | opt_GranMacros && node_reqd = yield liveness
-  | otherwise                   = nopC
+  | otherwise                   = return ()
   where
      liveness = mkRegLiveness regs 0 0