[PATCH v6 1/4] Adjust pdata function table entries sorting for AArch64

[Evgeny Karpov]

The .pdata section contains an array of function table entries that
are used for exception handling. The entries should be sorted by
begin address, which is usually the first 4 bytes RVA in the entry.
Entry sizes are different for x64 and AArch64.
This difference is addressed in this patch.

This is the first patch in the patch series implementing
Structured Exception Handling (SEH) for aarch64-w64-mingw32.

Co-authored-by: Zac Walker <zacwalker@microsoft.com>
Co-authored-by: Ron Riddle <ron.riddle@microsoft.com>
Signed-off-by: Evgeny Karpov <evgeny@kmaps.co>

bfd/ChangeLog:

	* peXXigen.c (defined): Use function_table_entry_size.
---
 bfd/peXXigen.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/bfd/peXXigen.c b/bfd/peXXigen.c
index 2ab0dd50bf4..36135582786 100644
--- a/bfd/peXXigen.c
+++ b/bfd/peXXigen.c
@@ -4724,9 +4724,21 @@ _bfd_XXi_final_link_postscript (bfd * abfd, struct coff_final_link_info *pfinfo)
 
 	if (bfd_malloc_and_get_section (abfd, sec, &tmp_data))
 	  {
+	    /* The size of a .pdata entry that describes a function that is used
+	       for exception handling.  */
+	    unsigned function_table_entry_size;
+#if defined (COFF_WITH_peAArch64)
+	    /* https://learn.microsoft.com/en-us/cpp/build/arm64-exception-handling#pdata-records.  */
+	    function_table_entry_size = 8;
+#else
+	    /* https://learn.microsoft.com/en-us/windows/win32/debug/pe-format#the-pdata-section.  */
+	    function_table_entry_size = 12;
+#endif
+	    /* .pdata entries should be sorted by the function start
+	       address.  */
 	    qsort (tmp_data,
-		   (size_t) (x / 12),
-		   12, sort_x64_pdata);
+		   (size_t) (x / function_table_entry_size),
+		   function_table_entry_size, sort_x64_pdata);
 	    bfd_set_section_contents (pfinfo->output_bfd, sec,
 				      tmp_data, 0, x);
 	    free (tmp_data);