[compiler-rt] [sanitizer] Change GetDTLSRange (PR #108345)

[Vitaly Buka via llvm-commits]

https://github.com/vitalybuka created https://github.com/llvm/llvm-project/pull/108345

We only need to change size, tls_beg should be unchanged.


>From cb612f248d232b407a4cde1c1a384b08e4040d2b Mon Sep 17 00:00:00 2001
From: Vitaly Buka <vitalybuka at google.com>
Date: Thu, 12 Sep 2024 01:26:07 -0700
Subject: [PATCH] =?UTF-8?q?[=F0=9D=98=80=F0=9D=97=BD=F0=9D=97=BF]=20initia?=
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Created using spr 1.3.4
---
 .../sanitizer_tls_get_addr.cpp                | 20 ++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_tls_get_addr.cpp b/compiler-rt/lib/sanitizer_common/sanitizer_tls_get_addr.cpp
index e5839f6f497474..17b9ff4aa6c40b 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_tls_get_addr.cpp
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_tls_get_addr.cpp
@@ -110,15 +110,15 @@ SANITIZER_WEAK_ATTRIBUTE
 const void *__sanitizer_get_allocated_begin(const void *p);
 }
 
-static bool GetDTLSRange(uptr &tls_beg, uptr &tls_size) {
+static uptr GetDTLSRange(uptr tls_beg) {
   const void *start = __sanitizer_get_allocated_begin((void *)tls_beg);
   if (!start)
-    return false;
-  tls_beg = (uptr)start;
-  tls_size = __sanitizer_get_allocated_size(start);
+    return 0;
+  CHECK_EQ(start, (void *)tls_beg);
+  uptr tls_size = __sanitizer_get_allocated_size(start);
   VReport(2, "__tls_get_addr: glibc DTLS suspected; tls={%p,0x%zx}\n",
           (void *)tls_beg, tls_size);
-  return true;
+  return tls_size;
 }
 
 DTLS::DTV *DTLS_on_tls_get_addr(void *arg_void, void *res,
@@ -142,10 +142,12 @@ DTLS::DTV *DTLS_on_tls_get_addr(void *arg_void, void *res,
     // creation.
     VReport(2, "__tls_get_addr: static tls: %p\n", (void *)tls_beg);
     tls_size = 0;
-  } else if (!GetDTLSRange(tls_beg, tls_size)) {
-    VReport(2, "__tls_get_addr: Can't guess glibc version\n");
-    // This may happen inside the DTOR of main thread, so just ignore it.
-    tls_size = 0;
+  } else {
+    tls_size = GetDTLSRange(tls_beg);
+    if (tls_size) {
+      VReport(2, "__tls_get_addr: Can't guess glibc version\n");
+      // This may happen inside the DTOR of main thread, so just ignore it.
+    }
   }
   dtv->beg = tls_beg;
   dtv->size = tls_size;