https://github.com/adrian-prantl created
https://github.com/llvm/llvm-project/pull/130209
where it can overflow a 2GB offset by just a little bit by applying a heuristic.
rdar://145888306
>From a6caecd1e1bae614579783ac1952e999eae5959d Mon Sep 17 00:00:00 2001
From: Adrian Prantl <apra...@apple.com>
Date: Thu, 6 Mar 2025 16:33:35 -0800
Subject: [PATCH] [lldb] Objective-C runtime: Work around abug in the shared
cache builder
where it can overflow a 2GB offset by just a little bit by applying a
heuristic.
rdar://145888306
---
.../ObjC/AppleObjCRuntime/AppleObjCRuntimeV2.cpp | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git
a/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntimeV2.cpp
b/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntimeV2.cpp
index ff17028e6662a..2dde490b549fe 100644
---
a/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntimeV2.cpp
+++
b/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntimeV2.cpp
@@ -458,7 +458,14 @@ __lldb_apple_objc_v2_get_shared_cache_class_info (void
*objc_opt_ro_ptr,
if (objc_opt->version == 16)
{
- const objc_clsopt_v16_t* clsopt = (const
objc_clsopt_v16_t*)((uint8_t *)objc_opt +
objc_opt_v16->largeSharedCachesClassOffset);
+ int32_t large_offset = objc_opt_v16->largeSharedCachesClassOffset;
+ const objc_clsopt_v16_t* clsopt = (const
objc_clsopt_v16_t*)((uint8_t *)objc_opt + large_offset);
+ // Work around a bug in some version shared cache builder where
the offset overflows 2GiB.
+ uint32_t unsigned_offset = (uint32_t)large_offset;
+ if (unsigned_offset > 0x7fffffff && unsigned_offset < 0x82000000) {
+ clsopt = (const objc_clsopt_v16_t*)((uint8_t *)objc_opt +
unsigned_offset);
+ DEBUG_PRINTF("warning: applying largeSharedCachesClassOffset
overflow workaround!\n");
+ }
const size_t max_class_infos =
class_infos_byte_size/sizeof(ClassInfo);
DEBUG_PRINTF("max_class_infos = %llu\n",
(uint64_t)max_class_infos);
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