From af77e5e4c08eac78d9395568167fdca2fa1bf914 Mon Sep 17 00:00:00 2001
From: Vitaly Buka <vitalybuka@google.com>
Date: Wed, 10 Aug 2022 20:53:02 -0700
Subject: [PATCH] [msan] Extract SetAllocaOrigin

---
 compiler-rt/lib/msan/msan.cpp | 56 ++++++++++++++++++++++++-------------------
 1 file changed, 32 insertions(+), 24 deletions(-)

diff --git a/compiler-rt/lib/msan/msan.cpp b/compiler-rt/lib/msan/msan.cpp
index c1c6805..380753b 100644
--- a/compiler-rt/lib/msan/msan.cpp
+++ b/compiler-rt/lib/msan/msan.cpp
@@ -303,6 +303,31 @@ u32 ChainOrigin(u32 id, StackTrace *stack) {
   return chained.raw_id();
 }
 
+// 'descr' is created at compile time and contains '----' in the beginning.
+// When we see descr for the first time we replace '----' with a uniq id
+// and set the origin to (id | (31-th bit)).
+static inline void SetAllocaOrigin(void *a, uptr size, char *descr, uptr pc) {
+  static const u32 dash = '-';
+  static const u32 first_timer =
+      dash + (dash << 8) + (dash << 16) + (dash << 24);
+  u32 *id_ptr = (u32 *)descr;
+  bool print = false;  // internal_strstr(descr + 4, "AllocaTOTest") != 0;
+  u32 id = *id_ptr;
+  if (id == first_timer) {
+    u32 idx = atomic_fetch_add(&NumStackOriginDescrs, 1, memory_order_relaxed);
+    CHECK_LT(idx, kNumStackOriginDescrs);
+    StackOriginDescr[idx] = descr + 4;
+    StackOriginPC[idx] = pc;
+    id = Origin::CreateStackOrigin(idx).raw_id();
+    *id_ptr = id;
+    if (print)
+      Printf("First time: idx=%d id=%d %s 0x%zx \n", idx, id, descr + 4, pc);
+  }
+  if (print)
+    Printf("__msan_set_alloca_origin: descr=%s id=%x\n", descr + 4, id);
+  __msan_set_origin(a, size, id);
+}
+
 }  // namespace __msan
 
 void __sanitizer::BufferedStackTrace::UnwindImpl(
@@ -581,34 +606,17 @@ void __msan_set_origin(const void *a, uptr size, u32 origin) {
   if (__msan_get_track_origins()) SetOrigin(a, size, origin);
 }
 
-// 'descr' is created at compile time and contains '----' in the beginning.
-// When we see descr for the first time we replace '----' with a uniq id
-// and set the origin to (id | (31-th bit)).
 void __msan_set_alloca_origin(void *a, uptr size, char *descr) {
-  __msan_set_alloca_origin4(
-      a, size, descr, StackTrace::GetPreviousInstructionPc(GET_CALLER_PC()));
+  SetAllocaOrigin(a, size, descr,
+                  StackTrace::GetPreviousInstructionPc(GET_CALLER_PC()));
 }
 
 void __msan_set_alloca_origin4(void *a, uptr size, char *descr, uptr pc) {
-  static const u32 dash = '-';
-  static const u32 first_timer =
-      dash + (dash << 8) + (dash << 16) + (dash << 24);
-  u32 *id_ptr = (u32*)descr;
-  bool print = false;  // internal_strstr(descr + 4, "AllocaTOTest") != 0;
-  u32 id = *id_ptr;
-  if (id == first_timer) {
-    u32 idx = atomic_fetch_add(&NumStackOriginDescrs, 1, memory_order_relaxed);
-    CHECK_LT(idx, kNumStackOriginDescrs);
-    StackOriginDescr[idx] = descr + 4;
-    StackOriginPC[idx] = pc;
-    id = Origin::CreateStackOrigin(idx).raw_id();
-    *id_ptr = id;
-    if (print)
-      Printf("First time: idx=%d id=%d %s 0x%zx \n", idx, id, descr + 4, pc);
-  }
-  if (print)
-    Printf("__msan_set_alloca_origin: descr=%s id=%x\n", descr + 4, id);
-  __msan_set_origin(a, size, id);
+  // Intentionally ignore pc and use return address. This function is here for
+  // compatibility, in case program is linked with library instrumented by
+  // older clang.
+  SetAllocaOrigin(a, size, descr,
+                  StackTrace::GetPreviousInstructionPc(GET_CALLER_PC()));
 }
 
 u32 __msan_chain_origin(u32 id) {
-- 
2.7.4