cmake: Add systemtap-sdt optional package support

CMakeLists.txt

@@ -47,6 +47,11 @@ tristate_option(CCACHE "Use ccache for compiling." "if ccache is found." AUTO)
 tristate_option(WITH_NATPMP "Enable NAT-PMP." "if libnatpmp is found." AUTO)
 tristate_option(WITH_MINIUPNPC "Enable UPnP." "if libminiupnpc is found." AUTO)
 tristate_option(WITH_ZMQ "Enable ZMQ notifications." "if libzmq is found." AUTO)
+tristate_option(WITH_USDT
+  "Enable tracepoints for Userspace, Statically Defined Tracing."
+  "if sys/sdt.h is found."
+  AUTO
+)
 
 if(CXX20)
   set(CMAKE_CXX_STANDARD 20)
@@ -144,6 +149,7 @@ message("Optional packages:")
 message("  NAT-PMP ............................. ${WITH_NATPMP}")
 message("  UPnP ................................ ${WITH_MINIUPNPC}")
 message("  ZeroMQ .............................. ${WITH_ZMQ}")
+message("  USDT tracing ........................ ${WITH_USDT}")
 message("")
 if(CMAKE_CROSSCOMPILING)
   set(cross_status "TRUE, for ${CMAKE_SYSTEM_NAME}, ${CMAKE_SYSTEM_PROCESSOR}")

cmake/bitcoin-config.h.in

@@ -33,6 +33,10 @@
 /* Copyright year */
 #define COPYRIGHT_YEAR @COPYRIGHT_YEAR@
 
+/* Define to 1 to enable tracepoints for Userspace, Statically Defined Tracing
+   */
+#cmakedefine ENABLE_TRACING 1
+
 /* Define this symbol if you have __builtin_clzl */
 #cmakedefine HAVE_BUILTIN_CLZL 1
 

cmake/optional.cmake

@@ -82,3 +82,24 @@ if(WITH_ZMQ)
     message(FATAL_ERROR "libzmq requested, but not found.")
   endif()
 endif()
+
+include(CheckCXXSourceCompiles)
+if(WITH_USDT)
+  check_cxx_source_compiles("
+    #include <sys/sdt.h>
+
+    int main()
+    {
+      DTRACE_PROBE(\"context\", \"event\");
+    }
+    " HAVE_USDT_H
+  )
+  if(HAVE_USDT_H)
+    set(ENABLE_TRACING TRUE)
+    set(WITH_USDT ON)
+  elseif(WITH_USDT STREQUAL "AUTO")
+    set(WITH_USDT OFF)
+  else()
+    message(FATAL_ERROR "sys/sdt.h requested, but not found.")
+  endif()
+endif()