From 8781abd79b5d8c8ce155b065c874d09076491e26 Mon Sep 17 00:00:00 2001
From: kcbanner <kcbanner@gmail.com>
Date: Fri, 5 Jun 2026 01:55:35 -0400
Subject: [PATCH] Coff: track the exports of a symbol so they can be updated

Globals created as exports of other symbols were not being updated when the original symbol moved.

Since we discover the entrypoint after exports are updated, nodes can move as a result of the entrypoint logic pulling in an input object.
---
 src/link/Coff.zig | 22 +++++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/src/link/Coff.zig b/src/link/Coff.zig
index beffbdce5d470fbca7d743ba0561011086309fc0..dbc2a81993d3ea6995aa0eb4b5bef538cccc5806 100644
--- a/src/link/Coff.zig
+++ b/src/link/Coff.zig
@@ -912,7 +912,8 @@ pub const Symbol = struct {
         dll_storage_class: DllStorageClass,
         // Only defined for .alias_si and .alias_name
         weak_external_strat: WeakExternalStrat,
-        _: u8 = 0,
+        has_exports: bool,
+        _: u7 = 0,
     },
     /// Relocations contained within this symbol
     loc_relocs: Reloc.Index,
@@ -924,7 +925,11 @@ pub const Symbol = struct {
         /// Only valid when outputting objects
         sti: SymbolTable.Index,
         /// Only valid when .ni == .input_section and .value_tag == .node_offset
+        /// TODO: This is only used for name lookups, could just be String?
         isli: Node.InputSection.LocalIndex,
+        /// Only valid if flags.has_exports is set. The first in a contiguous
+        /// list of symbols that are exports of this symbol.
+        first_export_si: Symbol.Index,
     },
 
     pub const DllStorageClass = enum(u2) {
@@ -1063,6 +1068,15 @@ pub const Symbol = struct {
             sym.rva = coff.computeNodeRva(sym.ni) + sym.nodeOffset(coff);
             si.applyLocationRelocs(coff);
             si.applyTargetRelocs(coff, .none);
+
+            if (sym.flags.has_exports) {
+                for (coff.symbols.items[@intFromEnum(sym.extra.first_export_si)..]) |*export_sym| {
+                    if (export_sym.ni != sym.ni) break;
+                    export_sym.rva = sym.rva;
+                    const export_si: Symbol.Index = @enumFromInt(export_sym - coff.symbols.items.ptr);
+                    export_si.applyTargetRelocs(coff, .none);
+                }
+            }
         }
 
         pub fn flushSymbolTableIndex(si: Symbol.Index, coff: *Coff) void {
@@ -2547,6 +2561,7 @@ fn addSymbolAssumeCapacity(coff: *Coff) Symbol.Index {
             .type = .unknown,
             .dll_storage_class = .default,
             .weak_external_strat = undefined,
+            .has_exports = false,
         },
         .loc_relocs = .none,
         .target_relocs = .none,
@@ -7063,9 +7078,14 @@ fn updateExportsInner(
     const machine = coff.targetLoad(&coff.headerPtr().machine);
     const exported_ni = exported_si.node(coff);
     const exported_sym = exported_si.get(coff);
+    exported_sym.extra = .{ .first_export_si = @enumFromInt(coff.symbols.items.len) };
+    exported_sym.flags.has_exports = true;
+
     for (export_indices) |export_index| {
         const @"export" = export_index.ptr(zcu);
         const name = @"export".opts.name.toSlice(ip);
+        // TODO: Add an errMsg if this conflicts with an existing global from an input
+        //       first_export_si relies on this being a new symbol.
         const export_si = try coff.globalSymbol(.{
             .name = name,
             .lib_name = null,
-- 
2.54.0