From 74ba5762ece3029bcac4934b430dd5180f54fe1c Mon Sep 17 00:00:00 2001
From: Jacob Young <jacobly0@users.noreply.github.com>
Date: Sun, 15 Dec 2024 22:46:02 -0500
Subject: [PATCH] Dwarf: preserve deduped struct navs

Previously, if multiple navs owned the same type due to being the same
zir node and having the same captures, they would overwrite each other.
Now, the navs codegenned later emit a decl alias to the first one.
---
 src/link/Dwarf.zig | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/link/Dwarf.zig b/src/link/Dwarf.zig
index 14a1190cf3..6bf311fe7f 100644
--- a/src/link/Dwarf.zig
+++ b/src/link/Dwarf.zig
@@ -2632,7 +2632,7 @@ pub fn updateComptimeNav(dwarf: *Dwarf, pt: Zcu.PerThread, nav_index: InternPool
 
             const type_gop = try dwarf.types.getOrPut(dwarf.gpa, nav_val.toIntern());
             if (type_gop.found_existing) {
-                dwarf.debug_info.section.getUnit(wip_nav.unit).getEntry(type_gop.value_ptr.*).clear();
+                if (dwarf.debug_info.section.getUnit(wip_nav.unit).getEntry(type_gop.value_ptr.*).len > 0) break :tag .decl_alias;
                 nav_gop.value_ptr.* = type_gop.value_ptr.*;
             } else {
                 if (nav_gop.found_existing)
@@ -2733,7 +2733,7 @@ pub fn updateComptimeNav(dwarf: *Dwarf, pt: Zcu.PerThread, nav_index: InternPool
 
             const type_gop = try dwarf.types.getOrPut(dwarf.gpa, nav_val.toIntern());
             if (type_gop.found_existing) {
-                dwarf.debug_info.section.getUnit(wip_nav.unit).getEntry(type_gop.value_ptr.*).clear();
+                if (dwarf.debug_info.section.getUnit(wip_nav.unit).getEntry(type_gop.value_ptr.*).len > 0) break :tag .decl_alias;
                 nav_gop.value_ptr.* = type_gop.value_ptr.*;
             } else {
                 if (nav_gop.found_existing)
@@ -2788,7 +2788,7 @@ pub fn updateComptimeNav(dwarf: *Dwarf, pt: Zcu.PerThread, nav_index: InternPool
 
             const type_gop = try dwarf.types.getOrPut(dwarf.gpa, nav_val.toIntern());
             if (type_gop.found_existing) {
-                dwarf.debug_info.section.getUnit(wip_nav.unit).getEntry(type_gop.value_ptr.*).clear();
+                if (dwarf.debug_info.section.getUnit(wip_nav.unit).getEntry(type_gop.value_ptr.*).len > 0) break :tag .decl_alias;
                 nav_gop.value_ptr.* = type_gop.value_ptr.*;
             } else {
                 if (nav_gop.found_existing)
@@ -2879,7 +2879,7 @@ pub fn updateComptimeNav(dwarf: *Dwarf, pt: Zcu.PerThread, nav_index: InternPool
 
             const type_gop = try dwarf.types.getOrPut(dwarf.gpa, nav_val.toIntern());
             if (type_gop.found_existing) {
-                dwarf.debug_info.section.getUnit(wip_nav.unit).getEntry(type_gop.value_ptr.*).clear();
+                if (dwarf.debug_info.section.getUnit(wip_nav.unit).getEntry(type_gop.value_ptr.*).len > 0) break :tag .decl_alias;
                 nav_gop.value_ptr.* = type_gop.value_ptr.*;
             } else {
                 if (nav_gop.found_existing)