Fix IAT (Import Address Table) alignment on PE32+

The IAT should be aligned to 8 bytes in aarch64-w64-mingw32, otherwise, it might
result in relocation issues.

When a function is imported from DLL, it generates the following code:

adrp    x19, __imp_fn
ldr     x19, [x19, #:lo12:__imp_fn]

8 byte alignment is required for ldr relocation. Addresses are placed in IAT.
The size of the chunk on AArch64 is 8 bytes.
If IAT is not aligned to 8 bytes, the relocation issue appears.
This patch fixes this issue by aligning IAT to 8 bytes for PE32+.

binutils/ChangeLog:

	* dlltool.c (make_head): Apply alignment to IAT.
	(make_delay_head): Apply alignment to Delay IAT.
	(main): Adjust 8 byte alignment for PE32+.

diff --git a/binutils/dlltool.c b/binutils/dlltool.c
index 94805fcd334525bfea46afcfd3729e7f49d1baff..f4ee894de1b257260b0f8d7a66582fc1c70674ba 100644 (file)
--- a/binutils/dlltool.c
+++ b/binutils/dlltool.c
@@ -2735,6 +2735,8 @@ make_head (void)
   if (!no_idata5)
     {
       fprintf (f, "\t.section\t.idata$5\n");
+      fprintf (f, "\t.p2align %d\n", secdata_plain[IDATA5].align);
+
       if (use_nul_prefixed_import_tables)
        {
          if (create_for_pep)
@@ -2828,6 +2830,8 @@ make_delay_head (void)
   if (!no_idata5)
     {
       fprintf (f, "\t.section\t.didat$5\n");
+      fprintf (f, "\t.p2align %d\n", secdata_delay[IDATA5].align);
+
       if (use_nul_prefixed_import_tables)
        {
          if (create_for_pep)
@@ -4013,6 +4017,14 @@ main (int ac, char **av)
   /* Check if we generated PE+.  */
   create_for_pep = (strcmp (mname, "i386:x86-64") == 0
                    || strcmp (mname, "arm64") == 0);
+  if (create_for_pep)
+    {
+      /* Update default 4 byte IAT (Import Address Table) alignment to 8 bytes
+        for PE32+.
+        https://learn.microsoft.com/en-us/windows/win32/debug/pe-format#import-address-table.  */
+      secdata_plain[IDATA5].align = 3;
+      secdata_delay[IDATA5].align = 3;
+    }
 
   /* Check the default underscore */
   if (leading_underscore == NULL)