[llvm-branch-commits] [compiler-rt] release/22.x: [sanitizer_common] [Darwin] Adopt _dyld_get_dyld_header (#182943) (PR #188913)

[via llvm-branch-commits]

https://github.com/llvmbot created https://github.com/llvm/llvm-project/pull/188913

Backport 2e7d07a33725a82ecfc514e27f047ece3ff13d4c

Requested by: @ndrewh

>From 462f684fd5575fcfce6ca41c403e2eb7fd53268e Mon Sep 17 00:00:00 2001
From: Andrew Haberlandt <ahaberlandt at apple.com>
Date: Tue, 24 Feb 2026 08:29:36 -0800
Subject: [PATCH] [sanitizer_common] [Darwin] Adopt _dyld_get_dyld_header
 (#182943)

(cherry picked from commit 2e7d07a33725a82ecfc514e27f047ece3ff13d4c)
---
 .../lib/sanitizer_common/sanitizer_procmaps_mac.cpp       | 8 ++++++--
 compiler-rt/lib/sanitizer_common/weak_symbols.txt         | 1 +
 compiler-rt/lib/tsan/go/buildgo.sh                        | 2 +-
 3 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_procmaps_mac.cpp b/compiler-rt/lib/sanitizer_common/sanitizer_procmaps_mac.cpp
index 979729f15aa16..93d3929033a86 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_procmaps_mac.cpp
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_procmaps_mac.cpp
@@ -176,7 +176,7 @@ void MemoryMappingLayout::Reset() {
 // The dyld load address should be unchanged throughout process execution,
 // and it is expensive to compute once many libraries have been loaded,
 // so cache it here and do not reset.
-static mach_header *dyld_hdr = 0;
+static const mach_header* dyld_hdr = 0;
 static const char kDyldPath[] = "/usr/lib/dyld";
 static const int kDyldImageIdx = -1;
 
@@ -244,14 +244,18 @@ extern intptr_t _dyld_get_image_slide(const struct mach_header* mh);
 extern int dyld_shared_cache_iterate_text(
     const uuid_t cacheUuid,
     void (^callback)(const dyld_shared_cache_dylib_text_info *info));
+SANITIZER_WEAK_IMPORT const struct mach_header* _dyld_get_dyld_header(void);
 }  // extern "C"
 
-static mach_header *GetDyldImageHeaderViaSharedCache() {
+static const mach_header* GetDyldImageHeaderViaSharedCache() {
   uuid_t uuid;
   bool hasCache = _dyld_get_shared_cache_uuid(uuid);
   if (!hasCache)
     return nullptr;
 
+  if (&_dyld_get_dyld_header != nullptr)
+    return _dyld_get_dyld_header();
+
   size_t cacheLength;
   __block uptr cacheStart = (uptr)_dyld_get_shared_cache_range(&cacheLength);
   CHECK(cacheStart && cacheLength);
diff --git a/compiler-rt/lib/sanitizer_common/weak_symbols.txt b/compiler-rt/lib/sanitizer_common/weak_symbols.txt
index 77e7b5d9f702e..600ab8a7c649c 100644
--- a/compiler-rt/lib/sanitizer_common/weak_symbols.txt
+++ b/compiler-rt/lib/sanitizer_common/weak_symbols.txt
@@ -10,3 +10,4 @@ ___sanitizer_symbolize_demangle
 ___sanitizer_symbolize_flush
 ___sanitizer_symbolize_set_demangle
 ___sanitizer_symbolize_set_inline_frames
+__dyld_get_dyld_header
diff --git a/compiler-rt/lib/tsan/go/buildgo.sh b/compiler-rt/lib/tsan/go/buildgo.sh
index d9e56402ad48f..1340071819fcb 100755
--- a/compiler-rt/lib/tsan/go/buildgo.sh
+++ b/compiler-rt/lib/tsan/go/buildgo.sh
@@ -165,7 +165,7 @@ elif [ "$GOOS" = "netbsd" ]; then
 	"
 elif [ "$GOOS" = "darwin" ]; then
 	OSCFLAGS="-fPIC -Wno-unused-const-variable -Wno-unknown-warning-option -mmacosx-version-min=10.7"
-	OSLDFLAGS="-lpthread -fPIC -fpie -mmacosx-version-min=10.7"
+	OSLDFLAGS="-lpthread -fPIC -fpie -mmacosx-version-min=10.7 -Wl,-U,__dyld_get_dyld_header"
 	SRCS="
 		$SRCS
 		../rtl/tsan_platform_mac.cpp