[compiler-rt] [NFC][sanitizer] Make `GetLibcVersion` `void` (PR #108915)

[Vitaly Buka via llvm-commits]

https://github.com/vitalybuka updated https://github.com/llvm/llvm-project/pull/108915

>From 51ec360811c547480fbc9a3da93fd4005aacc010 Mon Sep 17 00:00:00 2001
From: Vitaly Buka <vitalybuka at google.com>
Date: Mon, 16 Sep 2024 19:49:06 -0700
Subject: [PATCH] =?UTF-8?q?[=F0=9D=98=80=F0=9D=97=BD=F0=9D=97=BF]=20change?=
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Created using spr 1.3.4

[skip ci]
---
 .../sanitizer_linux_libcdep.cpp               | 50 ++++++++++++-------
 1 file changed, 33 insertions(+), 17 deletions(-)

diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_linux_libcdep.cpp b/compiler-rt/lib/sanitizer_common/sanitizer_linux_libcdep.cpp
index a5101291904430..5829692531e8d0 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_linux_libcdep.cpp
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_linux_libcdep.cpp
@@ -244,11 +244,11 @@ void InitTlsSize() {}
 // On glibc x86_64, ThreadDescriptorSize() needs to be precise due to the usage
 // of g_tls_size. On other targets, ThreadDescriptorSize() is only used by lsan
 // to get the pointer to thread-specific data keys in the thread control block.
-#  if (SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_SOLARIS) && \
-      !SANITIZER_ANDROID && !SANITIZER_GO
+#  if (SANITIZER_FREEBSD || SANITIZER_GLIBC) && !SANITIZER_GO
 // sizeof(struct pthread) from glibc.
 static atomic_uintptr_t thread_descriptor_size;
 
+// FIXME: Implementation is very GLIBC specific, but it's used by FREEBSD.
 static uptr ThreadDescriptorSizeFallback() {
 #    if defined(__x86_64__) || defined(__i386__) || defined(__arm__)
   int major;
@@ -281,19 +281,9 @@ static uptr ThreadDescriptorSizeFallback() {
     return FIRST_32_SECOND_64(1344, 2496);
   }
   return 0;
-#    elif defined(__s390__) || defined(__sparc__)
-  // The size of a prefix of TCB including pthread::{specific_1stblock,specific}
-  // suffices. Just return offsetof(struct pthread, specific_used), which hasn't
-  // changed since 2007-05. Technically this applies to i386/x86_64 as well but
-  // we call _dl_get_tls_static_info and need the precise size of struct
-  // pthread.
-  return FIRST_32_SECOND_64(524, 1552);
-#    elif defined(__mips__)
-  // TODO(sagarthakur): add more values as per different glibc versions.
-  return FIRST_32_SECOND_64(1152, 1776);
-#    elif SANITIZER_LOONGARCH64
-  return 1856;  // from glibc 2.36
-#    elif SANITIZER_RISCV64
+#    endif
+
+#    if SANITIZER_RISCV64
   int major;
   int minor;
   int patch;
@@ -307,10 +297,32 @@ static uptr ThreadDescriptorSizeFallback() {
     return 1936;    // tested against glibc 2.32
   }
   return 0;
-#    elif defined(__aarch64__)
+#    endif
+
+#    if defined(__s390__) || defined(__sparc__)
+  // The size of a prefix of TCB including pthread::{specific_1stblock,specific}
+  // suffices. Just return offsetof(struct pthread, specific_used), which hasn't
+  // changed since 2007-05. Technically this applies to i386/x86_64 as well but
+  // we call _dl_get_tls_static_info and need the precise size of struct
+  // pthread.
+  return FIRST_32_SECOND_64(524, 1552);
+#    endif
+
+#    if defined(__mips__)
+  // TODO(sagarthakur): add more values as per different glibc versions.
+  return FIRST_32_SECOND_64(1152, 1776);
+#    endif
+
+#    if SANITIZER_LOONGARCH64
+  return 1856;  // from glibc 2.36
+#    endif
+
+#    if defined(__aarch64__)
   // The sizeof (struct pthread) is the same from GLIBC 2.17 to 2.22.
   return 1776;
-#    elif defined(__powerpc64__)
+#    endif
+
+#    if defined(__powerpc64__)
   return 1776;  // from glibc.ppc64le 2.20-8.fc21
 #    endif
 }
@@ -351,6 +363,10 @@ static uptr TlsPreTcbSize() {
 }
 #    endif
 
+#  endif
+
+#  if (SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_SOLARIS) && \
+      !SANITIZER_ANDROID && !SANITIZER_GO
 namespace {
 struct TlsBlock {
   uptr begin, end, align;