From 8405d6f7e2d837e52eaedeb651d596d94297de91 Mon Sep 17 00:00:00 2001
From: Andrew Kelley <andrew@ziglang.org>
Date: Mon, 17 May 2021 13:46:54 -0700
Subject: [PATCH] link/MachO: bring in some of the Elf logic

There was missing incremental compilation logic in the MachO linker
code, causing test failures. With this logic ported over from the
corresponding ELF logic, tests pass again.
---
 src/link/MachO.zig | 46 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)

diff --git a/src/link/MachO.zig b/src/link/MachO.zig
index ff3cad7afa..fce447c742 100644
--- a/src/link/MachO.zig
+++ b/src/link/MachO.zig
@@ -1073,6 +1073,15 @@ fn freeTextBlock(self: *MachO, text_block: *TextBlock) void {
         // TODO shrink the __text section size here
         self.last_text_block = text_block.prev;
     }
+    if (self.d_sym) |*ds| {
+        if (ds.dbg_info_decl_first == text_block) {
+            ds.dbg_info_decl_first = text_block.dbg_info_next;
+        }
+        if (ds.dbg_info_decl_last == text_block) {
+            // TODO shrink the .debug_info section size here
+            ds.dbg_info_decl_last = text_block.dbg_info_prev;
+        }
+    }
 
     if (text_block.prev) |prev| {
         prev.next = text_block.next;
@@ -1091,6 +1100,20 @@ fn freeTextBlock(self: *MachO, text_block: *TextBlock) void {
     } else {
         text_block.next = null;
     }
+
+    if (text_block.dbg_info_prev) |prev| {
+        prev.dbg_info_next = text_block.dbg_info_next;
+
+        // TODO the free list logic like we do for text blocks above
+    } else {
+        text_block.dbg_info_prev = null;
+    }
+
+    if (text_block.dbg_info_next) |next| {
+        next.dbg_info_prev = text_block.dbg_info_prev;
+    } else {
+        text_block.dbg_info_next = null;
+    }
 }
 
 fn shrinkTextBlock(self: *MachO, text_block: *TextBlock, new_block_size: u64) void {
@@ -1477,6 +1500,29 @@ pub fn freeDecl(self: *MachO, decl: *Module.Decl) void {
 
         decl.link.macho.local_sym_index = 0;
     }
+    if (self.d_sym) |*ds| {
+        // TODO make this logic match freeTextBlock. Maybe abstract the logic
+        // out since the same thing is desired for both.
+        _ = ds.dbg_line_fn_free_list.remove(&decl.fn_link.macho);
+        if (decl.fn_link.macho.prev) |prev| {
+            ds.dbg_line_fn_free_list.put(self.base.allocator, prev, {}) catch {};
+            prev.next = decl.fn_link.macho.next;
+            if (decl.fn_link.macho.next) |next| {
+                next.prev = prev;
+            } else {
+                ds.dbg_line_fn_last = prev;
+            }
+        } else if (decl.fn_link.macho.next) |next| {
+            ds.dbg_line_fn_first = next;
+            next.prev = null;
+        }
+        if (ds.dbg_line_fn_first == &decl.fn_link.macho) {
+            ds.dbg_line_fn_first = decl.fn_link.macho.next;
+        }
+        if (ds.dbg_line_fn_last == &decl.fn_link.macho) {
+            ds.dbg_line_fn_last = decl.fn_link.macho.prev;
+        }
+    }
 }
 
 pub fn getDeclVAddr(self: *MachO, decl: *const Module.Decl) u64 {