From 3d4aabdf795edcb1e131ed3a2e3c2910d8343c85 Mon Sep 17 00:00:00 2001
From: Matthew Lugg <mlugg@mlugg.co.uk>
Date: Wed, 26 Aug 2026 09:14:45 +0100
Subject: [PATCH] Elf2: align the initial PLT size

I had kind of assumed that every target's PLT was no more aligned than
the size of an entire PLT entry, but apparently SPARC was determined to
prove me wrong on that front.
---
 src/link/Elf2.zig | 65 +++++++++++++++++++++++++++--------------------
 1 file changed, 38 insertions(+), 27 deletions(-)

diff --git a/src/link/Elf2.zig b/src/link/Elf2.zig
index 982740dceb046166a05e5c1c29864325274bb7a2..0f3656e6a13f7fa193b735361619e844526b7d26 100644
--- a/src/link/Elf2.zig
+++ b/src/link/Elf2.zig
@@ -4099,33 +4099,44 @@ fn initHeaders(
             .addralign = addr_align,
             .entsize = @intCast(addr_align.toByteUnits()),
         });
-        if (plt.got_plt) |got_plt| {
-            const got_plt_segment_ni = if (elf.options.z_now) elf.ni.data_rel_ro else elf.ni.data;
-            elf.shndx.got_plt = try elf.addSection(got_plt_segment_ni, .{
-                .name = ".got.plt",
-                .type = .PROGBITS,
-                .flags = .{ .WRITE = true, .ALLOC = true },
-                .size = got_plt.header_entries * elf.targetPtrSize(),
-                .addralign = addr_align,
-                .entsize = @intCast(addr_align.toByteUnits()),
-            });
-            elf.shndx.plt = try elf.addSection(elf.ni.text, .{
-                .name = ".plt",
-                .type = .PROGBITS,
-                .flags = .{ .ALLOC = true, .EXECINSTR = true },
-                .size = plt.entry_size * plt.header_entries,
-                .addralign = plt.@"align",
-                .node_align = node_block_align,
-            });
-        } else {
-            elf.shndx.plt = try elf.addSection(elf.phdrs.items[phndx.plt].unwrap().?, .{
-                .name = ".plt",
-                .type = .PROGBITS,
-                .flags = .{ .ALLOC = true, .WRITE = true, .EXECINSTR = true },
-                .size = plt.entry_size * plt.header_entries,
-                .addralign = plt.@"align",
-                .node_align = node_block_align,
-            });
+        {
+            const init_plt_size = plt.entry_size * plt.header_entries;
+            if (plt.got_plt) |got_plt| {
+                const got_plt_segment_ni = if (elf.options.z_now) elf.ni.data_rel_ro else elf.ni.data;
+                elf.shndx.got_plt = try elf.addSection(got_plt_segment_ni, .{
+                    .name = ".got.plt",
+                    .type = .PROGBITS,
+                    .flags = .{ .WRITE = true, .ALLOC = true },
+                    .size = got_plt.header_entries * elf.targetPtrSize(),
+                    .addralign = addr_align,
+                    .entsize = @intCast(addr_align.toByteUnits()),
+                });
+                elf.shndx.plt = try elf.addSection(elf.ni.text, .{
+                    .name = ".plt",
+                    .type = .PROGBITS,
+                    .flags = .{ .ALLOC = true, .EXECINSTR = true },
+                    .size = plt.@"align".forward(init_plt_size),
+                    .addralign = plt.@"align",
+                    .node_align = node_block_align,
+                });
+            } else {
+                elf.shndx.plt = try elf.addSection(elf.phdrs.items[phndx.plt].unwrap().?, .{
+                    .name = ".plt",
+                    .type = .PROGBITS,
+                    .flags = .{ .ALLOC = true, .WRITE = true, .EXECINSTR = true },
+                    .size = plt.@"align".forward(init_plt_size),
+                    .addralign = plt.@"align",
+                    .node_align = node_block_align,
+                });
+            }
+            // And the award for most annoying PLT requirement goes to SPARC, which decided that the
+            // whole table should have a greater alignment than the size of the individual entries,
+            // hence this bullshit:
+            if (plt.@"align".forward(init_plt_size) != init_plt_size) {
+                switch (elf.shdrPtr(elf.shndx.plt)) {
+                    inline else => |shdr| elf.targetStore(&shdr.size, init_plt_size),
+                }
+            }
         }
         if (plt.plt_sec != null) elf.shndx.plt_sec = try elf.addSection(elf.ni.text, .{
             .name = ".plt.sec",
-- 
2.54.0