[llvm] r296972 - Truncate thread names if they're too long.
Zachary Turner via llvm-commits
llvm-commits at lists.llvm.org
Sat Mar 4 08:42:26 PST 2017
Author: zturner
Date: Sat Mar 4 10:42:25 2017
New Revision: 296972
URL: http://llvm.org/viewvc/llvm-project?rev=296972&view=rev
Log:
Truncate thread names if they're too long.
Modified:
llvm/trunk/include/llvm/Support/Threading.h
llvm/trunk/lib/Support/Unix/Threading.inc
llvm/trunk/lib/Support/Windows/Threading.inc
Modified: llvm/trunk/include/llvm/Support/Threading.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/Threading.h?rev=296972&r1=296971&r2=296972&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Support/Threading.h (original)
+++ llvm/trunk/include/llvm/Support/Threading.h Sat Mar 4 10:42:25 2017
@@ -137,6 +137,10 @@ void llvm_execute_on_thread(void (*UserF
/// this.
uint64_t get_threadid();
+ /// \brief Get the maximum length of a thread name on this platform.
+ /// A value of 0 means there is no limit.
+ constexpr uint32_t get_max_thread_name_length();
+
/// \brief Set the name of the current thread. Setting a thread's name can
/// be helpful for enabling useful diagnostics under a debugger or when
/// logging. The level of support for setting a thread's name varies
Modified: llvm/trunk/lib/Support/Unix/Threading.inc
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/Unix/Threading.inc?rev=296972&r1=296971&r2=296972&view=diff
==============================================================================
--- llvm/trunk/lib/Support/Unix/Threading.inc (original)
+++ llvm/trunk/lib/Support/Unix/Threading.inc Sat Mar 4 10:42:25 2017
@@ -109,10 +109,35 @@ uint64_t llvm::get_threadid() {
}
+constexpr uint32_t llvm::get_max_thread_name_length() {
+#if defined(__NetBSD__)
+ return PTHREAD_MAX_NAMELEN_NP;
+#elif defined(__APPLE__)
+ return 64;
+#elif defined(__linux__)
+#if HAVE_PTHREAD_SETNAME_NP
+ return 16;
+#else
+ return 0;
+#endif
+#elif defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
+ return 16;
+#else
+ return 0;
+#endif
+}
+
void llvm::set_thread_name(const Twine &Name) {
// Make sure the input is null terminated.
SmallString<64> Storage;
StringRef NameStr = Name.toNullTerminatedStringRef(Storage);
+
+ // Truncate from the beginning, not the end, if the specified name is too
+ // long. For one, this ensures that the resulting string is still null
+ // terminated, but additionally the end of a long thread name will usually
+ // be more unique than the beginning, since a common pattern is for similar
+ // threads to share a common prefix.
+ NameStr = NameStr.take_back(get_max_thread_name_length());
(void)NameStr;
#if defined(__linux__)
#if (defined(__GLIBC__) && defined(_GNU_SOURCE)) || defined(__ANDROID__)
@@ -170,15 +195,14 @@ void llvm::get_thread_name(SmallVectorIm
free(kp);
return;
#elif defined(__NetBSD__)
- char buf[PTHREAD_MAX_NAMELEN_NP];
+ char buf[get_max_thread_name_length()];
::pthread_getname_np(::pthread_self(), buf, PTHREAD_MAX_NAMELEN_NP);
Name.append(buf, buf + strlen(buf));
#elif defined(__linux__)
#if (defined(__GLIBC__) && defined(_GNU_SOURCE)) || defined(__ANDROID__)
#if HAVE_PTHREAD_GETNAME_NP
- constexpr int MAXNAMELEN = 16;
- char Buffer[MAXNAMELEN];
+ char Buffer[get_max_thread_name_length()];
if (0 == ::pthread_getname_np(::pthread_self(), Buffer, MAXNAMELEN))
Name.append(Buffer, Buffer + strlen(Buffer));
#endif
Modified: llvm/trunk/lib/Support/Windows/Threading.inc
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/Windows/Threading.inc?rev=296972&r1=296971&r2=296972&view=diff
==============================================================================
--- llvm/trunk/lib/Support/Windows/Threading.inc (original)
+++ llvm/trunk/lib/Support/Windows/Threading.inc Sat Mar 4 10:42:25 2017
@@ -59,6 +59,8 @@ uint64_t llvm::get_threadid() {
return uint64_t(::GetCurrentThreadId());
}
+constexpr uint32_t llvm::get_max_thread_name_length() { return 0; }
+
void llvm::set_thread_name(const Twine &Name) {
#if defined(_MSC_VER)
// Make sure the input is null terminated.
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