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, 10 insertions, 7 deletions

diff --git a/compiler/cmm/PprCmm.hs b/compiler/cmm/PprCmm.hs
index 423bcd5504..f3e2a02737 100644
--- a/compiler/cmm/PprCmm.hs
+++ b/compiler/cmm/PprCmm.hs
@@ -75,6 +75,8 @@ instance Outputable ForeignConvention where
 instance Outputable ForeignTarget where
     ppr = pprForeignTarget
 
+instance Outputable CmmReturnInfo where
+    ppr = pprReturnInfo
 
 instance Outputable (Block CmmNode C C) where
     ppr = pprBlock
@@ -145,17 +147,18 @@ pprConvention (NativeDirectCall {}) = text "<native-direct-call-convention>"
 pprConvention (NativeReturn {})     = text "<native-ret-convention>"
 pprConvention  Slow                 = text "<slow-convention>"
 pprConvention  GC                   = text "<gc-convention>"
-pprConvention  PrimOpCall           = text "<primop-call-convention>"
-pprConvention  PrimOpReturn         = text "<primop-ret-convention>"
 
 pprForeignConvention :: ForeignConvention -> SDoc
-pprForeignConvention (ForeignConvention c as rs) = ppr c <> ppr as <> ppr rs
+pprForeignConvention (ForeignConvention c args res ret) =
+          doubleQuotes (ppr c) <+> text "arg hints: " <+> ppr args <+> text " result hints: " <+> ppr res <+> ppr ret
+
+pprReturnInfo :: CmmReturnInfo -> SDoc
+pprReturnInfo CmmMayReturn = empty
+pprReturnInfo CmmNeverReturns = ptext (sLit "never returns")
 
 pprForeignTarget :: ForeignTarget -> SDoc
-pprForeignTarget (ForeignTarget fn c) = ppr_fc c <+> ppr_target fn
-  where ppr_fc :: ForeignConvention -> SDoc
-        ppr_fc (ForeignConvention c args res) =
-          doubleQuotes (ppr c) <+> text "arg hints: " <+> ppr args <+> text " result hints: " <+> ppr res
+pprForeignTarget (ForeignTarget fn c) = ppr c <+> ppr_target fn
+  where
         ppr_target :: CmmExpr -> SDoc
         ppr_target t@(CmmLit _) = ppr t
         ppr_target fn'          = parens (ppr fn')