[llvm] [llvm] Validate Parent object before dereference (PR #157460)

[Daniel Kuts via llvm-commits]

https://github.com/apach301 updated https://github.com/llvm/llvm-project/pull/157460

>From 2894721aa05bbef0b9e5642e0e0c85045aac7446 Mon Sep 17 00:00:00 2001
From: Daniil Kutz <kutz at ispras.ru>
Date: Mon, 8 Sep 2025 16:10:32 +0300
Subject: [PATCH 1/3] [llvm] Validate Parent object before dereference

---
 llvm/lib/Object/Archive.cpp | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/llvm/lib/Object/Archive.cpp b/llvm/lib/Object/Archive.cpp
index 92f31c909efd4..c3111ebe0f525 100644
--- a/llvm/lib/Object/Archive.cpp
+++ b/llvm/lib/Object/Archive.cpp
@@ -472,10 +472,11 @@ Archive::Child::Child(const Archive *Parent, const char *Start, Error *Err)
     return;
   }
 
+  assert(Parent && "Parent can't be nullptr if Start is not a nullptr");
+
   Header = Parent->createArchiveMemberHeader(
       Start,
-      Parent ? Parent->getData().size() - (Start - Parent->getData().data())
-             : 0,
+      Parent->getData().size() - (Start - Parent->getData().data()),
       Err);
 
   // If we are pointed to real data, Start is not a nullptr, then there must be

>From 29d1ade943b097a0bafab520b6588eeeed6dd106 Mon Sep 17 00:00:00 2001
From: Daniil Kutz <kutz at ispras.ru>
Date: Tue, 9 Sep 2025 11:23:41 +0300
Subject: [PATCH 2/3] Fix linter error

---
 llvm/lib/Object/Archive.cpp | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/llvm/lib/Object/Archive.cpp b/llvm/lib/Object/Archive.cpp
index c3111ebe0f525..ad77dc93b494a 100644
--- a/llvm/lib/Object/Archive.cpp
+++ b/llvm/lib/Object/Archive.cpp
@@ -475,8 +475,7 @@ Archive::Child::Child(const Archive *Parent, const char *Start, Error *Err)
   assert(Parent && "Parent can't be nullptr if Start is not a nullptr");
 
   Header = Parent->createArchiveMemberHeader(
-      Start,
-      Parent->getData().size() - (Start - Parent->getData().data()),
+      Start, Parent->getData().size() - (Start - Parent->getData().data()),
       Err);
 
   // If we are pointed to real data, Start is not a nullptr, then there must be

>From ec4a38fe241f190c6d515a392873054a68538813 Mon Sep 17 00:00:00 2001
From: Daniil Kutz <kutz at ispras.ru>
Date: Tue, 9 Sep 2025 13:14:38 +0300
Subject: [PATCH 3/3] Remove redunant assert as Parent is always non-null

---
 llvm/lib/Object/Archive.cpp | 2 --
 1 file changed, 2 deletions(-)

diff --git a/llvm/lib/Object/Archive.cpp b/llvm/lib/Object/Archive.cpp
index ad77dc93b494a..753f805824cea 100644
--- a/llvm/lib/Object/Archive.cpp
+++ b/llvm/lib/Object/Archive.cpp
@@ -472,8 +472,6 @@ Archive::Child::Child(const Archive *Parent, const char *Start, Error *Err)
     return;
   }
 
-  assert(Parent && "Parent can't be nullptr if Start is not a nullptr");
-
   Header = Parent->createArchiveMemberHeader(
       Start, Parent->getData().size() - (Start - Parent->getData().data()),
       Err);