[llvm] Make llvm-strip not eat the .gnu_debuglink section (PR #78919)

[Felix Kellenbenz via llvm-commits]

https://github.com/felixkellenbenz updated https://github.com/llvm/llvm-project/pull/78919

>From f0a603cbf1866364257728c4111dbc31fc3bf72e Mon Sep 17 00:00:00 2001
From: Felix Kellenbenz <fe.kellenbenz.computer at outlook.de>
Date: Mon, 22 Jan 2024 00:49:21 +0100
Subject: [PATCH 1/3] Make llvm-strip not eat the .gnu_debuglink section

---
 llvm/lib/ObjCopy/ELF/ELFObjcopy.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/llvm/lib/ObjCopy/ELF/ELFObjcopy.cpp b/llvm/lib/ObjCopy/ELF/ELFObjcopy.cpp
index daf03810fd7bff..b6d77d17bae36c 100644
--- a/llvm/lib/ObjCopy/ELF/ELFObjcopy.cpp
+++ b/llvm/lib/ObjCopy/ELF/ELFObjcopy.cpp
@@ -450,6 +450,8 @@ static Error replaceAndRemoveSections(const CommonConfig &Config,
         return false;
       if (StringRef(Sec.Name).starts_with(".gnu.warning"))
         return false;
+      if (StringRef(Sec.Name).starts_with(".gnu_debuglink"))
+        return false;
       // We keep the .ARM.attribute section to maintain compatibility
       // with Debian derived distributions. This is a bug in their
       // patchset as documented here:

>From eb76f518a5be2e7ceb4eaea6f2489482c35ba339 Mon Sep 17 00:00:00 2001
From: Felix Kellenbenz <fe.kellenbenz.computer at outlook.de>
Date: Mon, 22 Jan 2024 10:37:22 +0100
Subject: [PATCH 2/3] Add test that checks if llvm-strip removes the
 .gnu_debuglink section

---
 llvm/test/tools/llvm-objcopy/ELF/strip-all.test | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/llvm/test/tools/llvm-objcopy/ELF/strip-all.test b/llvm/test/tools/llvm-objcopy/ELF/strip-all.test
index 20f3c9addf556b..efc3d42f22953f 100644
--- a/llvm/test/tools/llvm-objcopy/ELF/strip-all.test
+++ b/llvm/test/tools/llvm-objcopy/ELF/strip-all.test
@@ -68,6 +68,8 @@ Sections:
     Flags:           [ ]
   - Name:            .gnu.warning.foo
     Type:            SHT_PROGBITS
+  - Name:            .gnu_debuglink
+    Type:            SHT_PROGBITS
 ProgramHeaders:
   # Use an arbitrary segment type to show that the segment type is unimportant.
   - Type:     0x61234567

>From 4311d054750560113c182a9219d67c687231663e Mon Sep 17 00:00:00 2001
From: Felix Kellenbenz <fe.kellenbenz.computer at outlook.de>
Date: Mon, 22 Jan 2024 14:47:19 +0100
Subject: [PATCH 3/3] Add test to check that llvm-strip does not remove the
 .gnu_debuglink section

---
 llvm/test/tools/llvm-objcopy/ELF/strip-all.test | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/llvm/test/tools/llvm-objcopy/ELF/strip-all.test b/llvm/test/tools/llvm-objcopy/ELF/strip-all.test
index efc3d42f22953f..ba27a3509c6a31 100644
--- a/llvm/test/tools/llvm-objcopy/ELF/strip-all.test
+++ b/llvm/test/tools/llvm-objcopy/ELF/strip-all.test
@@ -76,10 +76,11 @@ ProgramHeaders:
     FirstSec: non_alloc_in_segment
     LastSec:  non_alloc_in_segment
 
-# CHECK: SectionHeaderCount: 6
+# CHECK: SectionHeaderCount: 7
 
 # CHECK: Name: non_alloc_in_segment
 # CHECK: Name: .bss
 # CHECK: Name: .text
 # CHECK: Name: .gnu.warning.foo
+# CHECK: Name: .gnu_debuglink
 # CHECK: Name: .shstrtab