https://github.com/gbMattN updated
https://github.com/llvm/llvm-project/pull/108385
>From 65f1e1fce67bfc9ae60f83abe6d3b487a174c6b1 Mon Sep 17 00:00:00 2001
From: Matthew Nagy <gbm...@tiger-linux2.domain.snsys.com>
Date: Thu, 12 Sep 2024 12:36:57 +0000
Subject: [PATCH] [TySan] Fix struct access with different bases
---
compiler-rt/lib/tysan/tysan.cpp | 4 +++
.../tysan/struct-offset-different-base.cpp | 31 +++++++++++++++++++
2 files changed, 35 insertions(+)
create mode 100644 compiler-rt/test/tysan/struct-offset-different-base.cpp
diff --git a/compiler-rt/lib/tysan/tysan.cpp b/compiler-rt/lib/tysan/tysan.cpp
index f627851d049e6a..f2cb6faddf45ac 100644
--- a/compiler-rt/lib/tysan/tysan.cpp
+++ b/compiler-rt/lib/tysan/tysan.cpp
@@ -128,6 +128,10 @@ static bool isAliasingLegalUp(tysan_type_descriptor *TDA,
break;
}
+ //You can't have negative offset, you must be partially inside the last
type
+ if (TDA->Struct.Members[Idx].Offset > OffsetA)
+ Idx -=1;
+
OffsetA -= TDA->Struct.Members[Idx].Offset;
TDA = TDA->Struct.Members[Idx].Type;
} else {
diff --git a/compiler-rt/test/tysan/struct-offset-different-base.cpp
b/compiler-rt/test/tysan/struct-offset-different-base.cpp
new file mode 100644
index 00000000000000..716d21f844f96c
--- /dev/null
+++ b/compiler-rt/test/tysan/struct-offset-different-base.cpp
@@ -0,0 +1,31 @@
+// RUN: %clangxx_tysan -O0 %s -o %t && %run %t >%t.out 2>&1
+// RUN: FileCheck %s < %t.out
+
+#include <stdio.h>
+
+struct inner {
+ char buffer;
+ int i;
+};
+
+void init_inner(inner *iPtr) {
+ iPtr->i = 0;
+}
+
+struct outer {
+ inner foo;
+ char buffer;
+};
+
+int main(void) {
+ outer *l = new outer();
+
+ init_inner(&l->foo);
+
+ int access_offsets_with_different_base = l->foo.i;
+ printf("%d\n", access_offsets_with_different_base);
+
+ return 0;
+}
+
+// CHECK-NOT: ERROR: TypeSanitizer: type-aliasing-violation
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