From 400094921cc3714875282ba96219af966c842d70 Mon Sep 17 00:00:00 2001
From: Pierre Muller <pierre@freepascal.org>
Date: Mon, 16 Sep 2024 18:28:52 +0000
Subject: [PATCH] Handle cross-endian case inside TCoffObjData.writereloc
 method

---
 compiler/ogcoff.pas | 37 ++++++++++++++++++++++++++++++++++++-
 1 file changed, 36 insertions(+), 1 deletion(-)

diff --git a/compiler/ogcoff.pas b/compiler/ogcoff.pas
index 06b4c2272f..b21fb48b88 100644
--- a/compiler/ogcoff.pas
+++ b/compiler/ogcoff.pas
@@ -1639,7 +1639,18 @@ const pemagic : array[0..3] of byte = (
 
 
     procedure TCoffObjData.writereloc(data:aint;len:aword;p:TObjSymbol;reloctype:TObjRelocationType);
+      type
+        multi = record
+          case integer of
+          0 : (ba : array[0..sizeof(aint)-1] of byte);
+          1 : (b : byte);
+          2 : (w : word);
+          4 : (d : dword);
+          8 : (q : qword);
+        end;
+
       var
+        ba : multi;
         curraddr,
         symaddr : aword;
       begin
@@ -1723,7 +1734,31 @@ const pemagic : array[0..3] of byte = (
             if reloctype=RELOC_RVA then
               internalerror(200603033);
           end;
-        CurrObjSec.write(data,len);
+        if target_info.endian<>source_info.endian then
+          begin
+            ba.q:=0;
+            if (len<=sizeof(data)) then
+              case len of
+                1 : ba.b:=byte(data);
+                2 : begin
+                      ba.w:=word(data);
+                      ba.w:=swapendian(ba.w);
+                    end;
+                4 : begin
+                      ba.d:=dword(data);
+                      ba.d:=swapendian(ba.d);
+                    end;
+                8 : begin
+                      ba.q:=qword(data);
+                      ba.q:=swapendian(ba.q);
+                    end;
+              else
+                internalerror(2024012501);
+              end;
+            CurrObjSec.write(ba,len);
+          end
+        else
+          CurrObjSec.write(data,len);
       end;