m68k: add some initial CPU-specifc boilerplate for an internal ELF writer

compiler/m68k/cpuelf.pas

@@ -0,0 +1,156 @@
+{
+    Copyright (c) 2022 by the Free Pascal Development team
+
+    Includes ELF-related code specific to m68k
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+ ****************************************************************************
+}
+unit cpuelf;
+
+{$i fpcdefs.inc}
+
+interface
+
+implementation
+
+  uses
+    verbose,elfbase,
+    systems,ogbase,ogelf,assemble;
+
+  const
+    {* Relocation types. *}
+    R_68K_NONE = 0;
+    R_68K_32 = 1;
+    R_68K_16 = 2;
+    R_68K_8 = 3;
+    R_68K_PC32 = 4;
+    R_68K_PC16 = 5;
+    R_68K_PC8 = 6;
+    R_68K_GOT32 = 7;
+    R_68K_GOT16 = 8;
+    R_68K_GOT8 = 9;
+    R_68K_GOT32O = 10;
+    R_68K_GOT16O = 11;
+    R_68K_GOT8O = 12;
+    R_68K_PLT32 = 13;
+    R_68K_PLT16 = 14;
+    R_68K_PLT8 = 15;
+    R_68K_PLT32O = 16;
+    R_68K_PLT16O = 17;
+    R_68K_PLT8O = 18;
+    R_68K_COPY = 19;
+    R_68K_GLOB_DAT = 20;
+    R_68K_JMP_SLOT = 21;
+    R_68K_RELATIVE = 22;
+
+    R_68K_GNU_VTINHERIT = 23;
+    R_68K_GNU_VTENTRY = 24;
+
+    R_68K_TLS_GD32 = 25;
+    R_68K_TLS_GD16 = 26;
+    R_68K_TLS_GD8 = 27;
+    R_68K_TLS_LDM32 = 28;
+    R_68K_TLS_LDM16 = 29;
+    R_68K_TLS_LDM8 = 30;
+    R_68K_TLS_LDO32 = 31;
+    R_68K_TLS_LDO16 = 32;
+    R_68K_TLS_LDO8 = 33;
+    R_68K_TLS_IE32 = 34;
+    R_68K_TLS_IE16 = 35;
+    R_68K_TLS_IE8 = 36;
+    R_68K_TLS_LE32 = 37;
+    R_68K_TLS_LE16 = 38;
+    R_68K_TLS_LE8 = 39;
+    R_68K_TLS_DTPMOD32 = 40;
+    R_68K_TLS_DTPREL32 = 41;
+    R_68K_TLS_TPREL32 = 42;
+
+{****************************************************************************
+                               ELF Target methods
+****************************************************************************}
+
+   function elf_m68k_encodereloc(objrel:TObjRelocation):byte;
+     begin
+       case objrel.typ of
+         RELOC_NONE :
+           result:=R_68K_NONE;
+         RELOC_ABSOLUTE :
+           result:=R_68K_32;
+         { TODO }
+       else
+         result:=0;
+         InternalError(2022122901);
+       end;
+     end;
+
+
+   function elf_m68k_relocname(reltyp:byte):string;
+     begin
+       result:='TODO';
+     end;
+
+
+   procedure elf_m68k_loadreloc(objrel:TObjRelocation);
+     begin
+     end;
+
+
+
+{*****************************************************************************
+                                    Initialize
+*****************************************************************************}
+
+  const
+    elf_target_m68k: TElfTarget =
+      (
+        max_page_size:     $8000; // fixme
+        exe_image_base:    $8000; // fixme
+        machine_code:      EM_M68K;
+        relocs_use_addend: false;
+        dyn_reloc_codes: (
+          R_68K_RELATIVE,
+          R_68K_GLOB_DAT,
+          R_68K_JMP_SLOT,
+          R_68K_COPY,
+          0      // IRELATIVE is absent(?)
+        );
+        relocname:         @elf_m68k_relocName;
+        encodereloc:       @elf_m68k_encodeReloc;
+        loadreloc:         @elf_m68k_loadReloc;
+        loadsection:       nil;
+        encodeflags:       nil;
+      );
+
+    as_m68k_elf32_info : tasminfo =
+       (
+         id     : as_m68k_elf32;
+         idtxt  : 'ELF';
+         asmbin : '';
+         asmcmd : '';
+         supported_targets : [system_m68k_amiga,system_m68k_embedded];
+         flags : [af_outputbinary,af_smartlink_sections];
+         labelprefix : '.L';
+         labelmaxlen : -1;
+         comment : '';
+         dollarsign: '$';
+       );
+
+initialization
+  RegisterAssembler(as_m68k_elf32_info,TElfAssembler);
+  ElfTarget:=elf_target_m68k;
+end.
+

compiler/systems.inc

@@ -279,6 +279,7 @@
              ,as_arm_vasm
              ,as_wasm32_wasm
              ,as_clang_llvm_darwin
+             ,as_m68k_elf32
        );
 
        tlink = (ld_none,