Factor out unregisterised and tables next to code m4 macros

These will be useful for upcoming RTS configure script.

2 files changed, 67 insertions, 0 deletions

diff --git a/m4/ghc_tables_next_to_code.m4 b/m4/ghc_tables_next_to_code.m4
new file mode 100644
index 0000000000..0f262bba57
--- /dev/null
+++ b/m4/ghc_tables_next_to_code.m4
@@ -0,0 +1,41 @@
+# GHC_TABLES_NEXT_TO_CODE
+# --------------------------------
+# Do a build with tables next to code?
+#
+# Whether the target architecture supports placing info tables
+# directly before the entry code (see TABLES_NEXT_TO_CODE in the RTS).
+# Whether we actually compile for TABLES_NEXT_TO_CODE depends on
+# whether we're building unregisterised code or not, which may be
+# decided by options to the compiler later.
+#
+# See https://gitlab.haskell.org/ghc/ghc/wikis/commentary/rts/storage/heap-objects#tables_next_to_code
+#
+AC_DEFUN([GHC_TABLES_NEXT_TO_CODE],
+[
+  AC_REQUIRE([GHC_UNREGISTERISED])
+  AC_MSG_CHECKING(whether target supports tables next to code)
+  case "$Unregisterised" in
+      NO)
+          case "$TargetArch" in
+              ia64|powerpc64|powerpc64le|s390x)
+                  TablesNextToCodeDefault=NO
+                  AC_MSG_RESULT([no])
+                  ;;
+              *)
+                  TablesNextToCodeDefault=YES
+                  AC_MSG_RESULT([yes])
+                  ;;
+          esac
+          ;;
+      YES)
+          TablesNextToCodeDefault=NO
+          AC_MSG_RESULT([no])
+          ;;
+  esac
+  FP_DEFAULT_CHOICE_OVERRIDE_CHECK(
+    [tables-next-to-code],
+    [tables next to code],
+    [tables apart from code],
+    [TablesNextToCode],
+    [Build a tool chain with info tables laid out next to code (enabled by default when using the registerised ABI, on platforms that support it)])
+])
diff --git a/m4/ghc_unregisterised.m4 b/m4/ghc_unregisterised.m4
new file mode 100644
index 0000000000..ca3beb8733
--- /dev/null
+++ b/m4/ghc_unregisterised.m4
@@ -0,0 +1,26 @@
+# GHC_UNREGISTERISED
+# --------------------------------
+#  Do an unregisterised build?
+AC_DEFUN([GHC_UNREGISTERISED],
+[
+  AC_MSG_CHECKING(whether target supports a registerised ABI)
+  case "$TargetArch" in
+      i386|x86_64|powerpc|powerpc64|powerpc64le|s390x|arm|aarch64|riscv64)
+          UnregisterisedDefault=NO
+          AC_MSG_RESULT([yes])
+          ;;
+      *)
+          UnregisterisedDefault=YES
+          AC_MSG_RESULT([no])
+          ;;
+  esac
+  FP_DEFAULT_CHOICE_OVERRIDE_CHECK(
+    [unregisterised],
+    [unregisterised],
+    [registerised],
+    [Unregisterised],
+    [Build a toolchain with the unregisterised ABI (disabled by default on platforms with registerised support)],
+    [NO],
+    [YES],
+    [no])
+])