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, 9 insertions, 4 deletions

diff --git a/compiler/cmm/CmmPipeline.hs b/compiler/cmm/CmmPipeline.hs
index 5fca9e7164..4f5d3b926c 100644
--- a/compiler/cmm/CmmPipeline.hs
+++ b/compiler/cmm/CmmPipeline.hs
@@ -52,7 +52,7 @@ cmmPipeline hsc_env topSRT prog =
 
 cpsTop :: HscEnv -> CmmDecl -> IO (CAFEnv, [CmmDecl])
 cpsTop _ p@(CmmData {}) = return (mapEmpty, [p])
-cpsTop hsc_env (CmmProc h@(TopInfo {stack_info=StackInfo {arg_space=entry_off}}) l g) =
+cpsTop hsc_env proc =
     do
        ----------- Control-flow optimisations ----------------------------------
 
@@ -60,10 +60,13 @@ cpsTop hsc_env (CmmProc h@(TopInfo {stack_info=StackInfo {arg_space=entry_off}})
        -- later passes by removing lots of empty blocks, so we do it
        -- even when optimisation isn't turned on.
        --
-       g <- {-# SCC "cmmCfgOpts(1)" #-}
-            return $ cmmCfgOpts splitting_proc_points g
+       CmmProc h l g <- {-# SCC "cmmCfgOpts(1)" #-}
+            return $ cmmCfgOptsProc splitting_proc_points proc
        dump Opt_D_dump_cmmz_cfg "Post control-flow optimsations" g
 
+       let !TopInfo {stack_info=StackInfo { arg_space = entry_off
+                                          , do_layout = do_layout }} = h
+
        ----------- Eliminate common blocks -------------------------------------
        g <- {-# SCC "elimCommonBlocks" #-}
             condPass Opt_CmmElimCommonBlocks elimCommonBlocks g
@@ -95,7 +98,9 @@ cpsTop hsc_env (CmmProc h@(TopInfo {stack_info=StackInfo {arg_space=entry_off}})
        ----------- Layout the stack and manifest Sp ----------------------------
        (g, stackmaps) <-
             {-# SCC "layoutStack" #-}
-            runUniqSM $ cmmLayoutStack dflags proc_points entry_off g
+            if do_layout
+               then runUniqSM $ cmmLayoutStack dflags proc_points entry_off g
+               else return (g, mapEmpty)
        dump Opt_D_dump_cmmz_sp "Layout Stack" g
 
        ----------- Sink and inline assignments *after* stack layout ------------