From 0efc4711220d98d8c0178dfe9d64dc897c6dee70 Mon Sep 17 00:00:00 2001
From: Jakub Konka <kubkon@jakubkonka.com>
Date: Thu, 9 Nov 2023 12:02:20 +0100
Subject: [PATCH] elf: calculate required size for .rela.eh_frame

---
 src/link/Elf.zig          |  5 +++++
 src/link/Elf/eh_frame.zig | 16 ++++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/src/link/Elf.zig b/src/link/Elf.zig
index 13ea069a3a..009207ba09 100644
--- a/src/link/Elf.zig
+++ b/src/link/Elf.zig
@@ -4245,6 +4245,11 @@ fn updateSectionSizesObject(self: *Elf) !void {
 
     if (self.eh_frame_section_index) |index| {
         self.shdrs.items[index].sh_size = try eh_frame.calcEhFrameSize(self);
+
+        if (self.eh_frame_rela_section_index) |rela_index| {
+            const shdr = &self.shdrs.items[rela_index];
+            shdr.sh_size = eh_frame.calcEhFrameRelocs(self) * shdr.sh_entsize;
+        }
     }
 
     try self.updateSymtabSize();
diff --git a/src/link/Elf/eh_frame.zig b/src/link/Elf/eh_frame.zig
index 8c0fa0f769..d15af3489a 100644
--- a/src/link/Elf/eh_frame.zig
+++ b/src/link/Elf/eh_frame.zig
@@ -282,6 +282,22 @@ pub fn calcEhFrameHdrSize(elf_file: *Elf) usize {
     return eh_frame_hdr_header_size + count * 8;
 }
 
+pub fn calcEhFrameRelocs(elf_file: *Elf) usize {
+    var count: usize = 0;
+    for (elf_file.objects.items) |index| {
+        const object = elf_file.file(index).?.object;
+        for (object.cies.items) |cie| {
+            if (!cie.alive) continue;
+            count += cie.relocs(elf_file).len;
+        }
+        for (object.fdes.items) |fde| {
+            if (!fde.alive) continue;
+            count += fde.relocs(elf_file).len;
+        }
+    }
+    return count;
+}
+
 fn resolveReloc(rec: anytype, sym: *const Symbol, rel: elf.Elf64_Rela, elf_file: *Elf, contents: []u8) !void {
     const offset = std.math.cast(usize, rel.r_offset - rec.offset) orelse return error.Overflow;
     const P = @as(i64, @intCast(rec.address(elf_file) + offset));