From 7dcfda815c569ddcf2a7f860a176be50cc942bff Mon Sep 17 00:00:00 2001
From: Timo Kreuzer <timo.kreuzer@reactos.org>
Date: Fri, 13 Sep 2024 21:06:20 +0300
Subject: [PATCH] [SPEC2DEF] Use explicit ordinals on MSVC, too

This prevents MSVC from reordering the exports in a way that doesn't match our spec file. Also improve the algorithm to apply ordinals, by starting with the first specified ordinal, possibly reserving ordinals for anything declared without an ordinal before.
---
 sdk/tools/spec2def/spec2def.c | 33 ++++++++++++++++++++++++---------
 1 file changed, 24 insertions(+), 9 deletions(-)

diff --git a/sdk/tools/spec2def/spec2def.c b/sdk/tools/spec2def/spec2def.c
index 55955ee605e..36612eb4bfc 100644
--- a/sdk/tools/spec2def/spec2def.c
+++ b/sdk/tools/spec2def/spec2def.c
@@ -781,8 +781,8 @@ OutputLine_def(FILE *fileDest, EXPORT *pexp)
     else
         OutputLine_def_GCC(fileDest, pexp);
 
-    /* On GCC builds we force ordinals */
-    if ((pexp->uFlags & FL_ORDINAL) || (!gbMSComp && !gbImportLib))
+    /* If it is not an import lib, we force ordinals */
+    if ((pexp->uFlags & FL_ORDINAL) || !gbImportLib)
     {
         fprintf(fileDest, " @%d", pexp->nOrdinal);
     }
@@ -1421,6 +1421,7 @@ ApplyOrdinals(EXPORT* pexports, unsigned cExports)
 {
     unsigned short i, j;
     char* used;
+    unsigned short firstOrdinal = 0xFFFF, firstIndex = 0;
 
     /* Allocate a table to mark used ordinals */
     used = malloc(65536);
@@ -1442,11 +1443,28 @@ ApplyOrdinals(EXPORT* pexports, unsigned cExports)
                 return -1;
             }
             used[pexports[i].nOrdinal] = 1;
+            if (pexports[i].nOrdinal < firstOrdinal)
+            {
+                firstOrdinal = pexports[i].nOrdinal;
+                firstIndex = i;
+            }
         }
     }
 
+    /* Check if we found an ordinal and it's larger than it's index */
+    if ((firstOrdinal != 0xFFFF) && (firstOrdinal > firstIndex))
+    {
+        /* We did. Calculate an appropriate starting ordinal. */
+        firstOrdinal -= firstIndex;
+    }
+    else
+    {
+        /* We didn't, so start with 1 */
+        firstOrdinal = 1;
+    }
+
     /* Pass 2: apply available ordinals */
-    for (i = 0, j = 1; i < cExports; i++)
+    for (i = 0, j = firstOrdinal; i < cExports; i++)
     {
         if ((pexports[i].uFlags & FL_ORDINAL) == 0 && pexports[i].bVersionIncluded)
         {
@@ -1640,13 +1658,10 @@ int main(int argc, char *argv[])
         return -1;
     }
 
-    if (!gbMSComp)
+    if (ApplyOrdinals(pexports, cExports) < 0)
     {
-        if (ApplyOrdinals(pexports, cExports) < 0)
-        {
-            fprintf(stderr, "error: could not apply ordinals!\n");
-            return -1;
-        }
+        fprintf(stderr, "error: could not apply ordinals!\n");
+        return -1;
     }
 
     if (pszDefFileName)