elf: claim unresolved dangling symbols as undef externs in -r mode

3 files changed, 37 insertions, 5 deletions

diff --git a/src/link/Elf/Atom.zig b/src/link/Elf/Atom.zig
index 95202a3d4c..09a16e4240 100644
--- a/src/link/Elf/Atom.zig
+++ b/src/link/Elf/Atom.zig
@@ -294,6 +294,8 @@ pub fn relocs(self: Atom, elf_file: *Elf) []align(1) const elf.Elf64_Rela {
 }
 
 pub fn writeRelocs(self: Atom, elf_file: *Elf, out_relocs: *std.ArrayList(elf.Elf64_Rela)) !void {
+    relocs_log.debug("0x{x}: {s}", .{ self.value, self.name(elf_file) });
+
     const file_ptr = self.file(elf_file).?;
     for (self.relocs(elf_file)) |rel| {
         const target_index = switch (file_ptr) {
@@ -302,15 +304,27 @@ pub fn writeRelocs(self: Atom, elf_file: *Elf, out_relocs: *std.ArrayList(elf.El
             else => unreachable,
         };
         const target = elf_file.symbol(target_index);
-        const r_sym = target.outputSymtabIndex(elf_file);
-        const r_offset = self.value + rel.r_offset;
-        const r_addend = rel.r_addend;
         const r_type = switch (rel.r_type()) {
             Elf.R_X86_64_ZIG_GOT32,
             Elf.R_X86_64_ZIG_GOTPCREL,
             => unreachable, // Sanity check if we accidentally emitted those.
             else => |r_type| r_type,
         };
+        const r_offset = self.value + rel.r_offset;
+        const r_addend = rel.r_addend;
+        const r_sym = switch (target.type(elf_file)) {
+            elf.STT_SECTION => elf_file.sectionSymbolOutputSymtabIndex(target.outputShndx().?),
+            else => target.outputSymtabIndex(elf_file),
+        };
+
+        relocs_log.debug("  {s}: [{x} => {d}({s})] + {x}", .{
+            fmtRelocType(r_type),
+            r_offset,
+            r_sym,
+            target.name(elf_file),
+            r_addend,
+        });
+
         out_relocs.appendAssumeCapacity(.{
             .r_offset = r_offset,
             .r_addend = r_addend,
diff --git a/src/link/Elf/Object.zig b/src/link/Elf/Object.zig
index 8a402ad7d2..0a4232d3b1 100644
--- a/src/link/Elf/Object.zig
+++ b/src/link/Elf/Object.zig
@@ -491,6 +491,25 @@ pub fn claimUnresolved(self: *Object, elf_file: *Elf) void {
     }
 }
 
+pub fn claimUnresolvedObject(self: *Object, elf_file: *Elf) void {
+    const first_global = self.first_global orelse return;
+    for (self.globals(), 0..) |index, i| {
+        const esym_index = @as(u32, @intCast(first_global + i));
+        const esym = self.symtab.items[esym_index];
+        if (esym.st_shndx != elf.SHN_UNDEF) continue;
+
+        const global = elf_file.symbol(index);
+        if (global.file(elf_file)) |file| {
+            if (global.elfSym(elf_file).st_shndx != elf.SHN_UNDEF or file.index() <= self.index) continue;
+        }
+
+        global.value = 0;
+        global.atom_index = 0;
+        global.esym_index = esym_index;
+        global.file_index = self.index;
+    }
+}
+
 pub fn markLive(self: *Object, elf_file: *Elf) void {
     const first_global = self.first_global orelse return;
     for (self.globals(), 0..) |index, i| {
diff --git a/src/link/Elf/ZigObject.zig b/src/link/Elf/ZigObject.zig
index 07c492431c..798ced73a5 100644
--- a/src/link/Elf/ZigObject.zig
+++ b/src/link/Elf/ZigObject.zig
@@ -377,8 +377,7 @@ pub fn claimUnresolvedObject(self: ZigObject, elf_file: *Elf) void {
 
         const global = elf_file.symbol(index);
         if (global.file(elf_file)) |file| {
-            if (global.elfSym(elf_file).st_shndx != elf.SHN_UNDEF or
-                file.index() <= self.index) continue;
+            if (global.elfSym(elf_file).st_shndx != elf.SHN_UNDEF or file.index() <= self.index) continue;
         }
 
         global.value = 0;