Allow signposts to take advantage of deferred string substitution

One nice feature of the os_signpost API is that format string
substitutions happen in the consumer, not the logging
application. LLVM's current Signpost class doesn't take advantage of
this though and instead always uses a static "Begin/End %s" format
string.

This patch uses variadic macros to allow the API to be used as
intended. Unfortunately, the primary use-case I had in mind (the
LLDB_SCOPED_TIMER() macro) does not get much better from this, because
__PRETTY_FUNCTION__ is *not* a macro, but a static string, so
signposts created by LLDB_SCOPED_TIMER() still use a static "%s"
format string. At least LLDB_SCOPED_TIMERF() works as intended.

This reapplies the previsously reverted patch with support for
platforms where signposts are unavailable.

Differential Revision: https://reviews.llvm.org/D103575

1 files changed, 1 insertions, 1 deletions

diff --git a/llvm/lib/Support/Timer.cpp b/llvm/lib/Support/Timer.cpp
index 6e592db..8d421db 100644
--- a/llvm/lib/Support/Timer.cpp
+++ b/llvm/lib/Support/Timer.cpp
@@ -174,7 +174,7 @@ void Timer::stopTimer() {
   Running = false;
   Time += TimeRecord::getCurrentTime(false);
   Time -= StartTime;
-  Signposts->endInterval(this, getName());
+  Signposts->endInterval(this);
 }
 
 void Timer::clear() {