Add PrimCallConv support to GHCiwip/ghci-primcall

This adds support for calling Cmm code from bytecode using the native
calling convention, allowing modules that use `foreign import prim`
to be loaded and debugged in GHCi.

This patch introduces a new `PRIMCALL` bytecode instruction and
a helper stack frame `stg_primcall`. The code is based on the
existing functionality for dealing with unboxed tuples in bytecode,
which has been generalised to handle arbitrary calls.

Fixes #22051

1 files changed, 3 insertions, 0 deletions

diff --git a/rts/Disassembler.c b/rts/Disassembler.c
index ae6d7ac9f7..f8b270fa28 100644
--- a/rts/Disassembler.c
+++ b/rts/Disassembler.c
@@ -83,6 +83,9 @@ disInstr ( StgBCO *bco, int pc )
          debugBelch("CCALL    marshaller at 0x%" FMT_HexWord "\n",
                          literals[instrs[pc]] );
          pc += 1; break;
+      case bci_PRIMCALL:
+         debugBelch("PRIMCALL\n");
+         break;
      case bci_STKCHECK:  {
          StgWord stk_words_reqd = BCO_GET_LARGE_ARG + 1;
          debugBelch("STKCHECK %" FMT_Word "\n", (W_)stk_words_reqd );