From b04836876404fa94e3d3f1b26f1e3cc95e307185 Mon Sep 17 00:00:00 2001 From: fanquake Date: Fri, 18 Jun 2021 15:15:33 +0800 Subject: [PATCH] Merge bitcoin/bitcoin#22238: build: improve detection of eBPF support 8f7704d0321a71c1691837a6bd3b4e05f84d3031 build: improve detection of eBPF support (fanquake) Pull request description: Just checking for the `sys/sdt.h` header isn't enough, as systems like macOS have the header, but it doesn't actually have the `DTRACE_PROBE*` probes, which leads to [compile failures](https://github.com/bitcoin/bitcoin/pull/22006#issuecomment-859559004). The contents of `sys/sdt.h` in the macOS SDK is: ```bash #ifndef _SYS_SDT_H #define _SYS_SDT_H /* * This is a wrapper header that wraps the mach visible sdt.h header so that * the header file ends up visible where software expects it to be. We also * do the C/C++ symbol wrapping here, since Mach headers are technically C * interfaces. * * Note: The process of adding USDT probes to code is slightly different * than documented in the "Solaris Dynamic Tracing Guide". * The DTRACE_PROBE*() macros are not supported on Mac OS X -- instead see * "BUILDING CODE CONTAINING USDT PROBES" in the dtrace(1) manpage * */ #include __BEGIN_DECLS #include __END_DECLS #endif /* _SYS_SDT_H */ ``` The `BUILDING CODE CONTAINING USDT PROBES` section from the dtrace manpage is available [here](https://gist.github.com/fanquake/e56c9866d53b326646d04ab43a8df9e2), and outlines the more involved process of using USDT probes on macOS. ACKs for top commit: jb55: utACK 8f7704d0321a71c1691837a6bd3b4e05f84d3031 practicalswift: cr ACK 8f7704d0321a71c1691837a6bd3b4e05f84d3031 hebasto: ACK 8f7704d0321a71c1691837a6bd3b4e05f84d3031, tested on macOS Big Sur 11.4 (20F71) and on Linux Mint 20.1 (x86_64) with depends. Tree-SHA512: 5f1351d0ac2e655fccb22a5454f415906404fdaa336fd89b54ef49ca50a442c44ab92d063cba3f161cb8ea0679c92ae3cd6cfbbcb19728cac21116247a017df5 --- configure.ac | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) diff --git a/configure.ac b/configure.ac index 479907f2a9..d7fe9c6e36 100644 --- a/configure.ac +++ b/configure.ac @@ -1353,13 +1353,15 @@ if test x$enable_wallet != xno; then fi if test x$use_ebpf != xno; then - AC_CHECK_HEADER([sys/sdt.h], [have_sdt=yes], [have_sdt=no]) -else - have_sdt=no -fi - -if test x$have_sdt = xyes; then - AC_DEFINE([ENABLE_TRACING], [1], [Define to 1 to enable eBPF user static defined tracepoints]) + AC_MSG_CHECKING([whether eBPF tracepoints are supported]) + AC_COMPILE_IFELSE([ + AC_LANG_PROGRAM( + [#include ], + [DTRACE_PROBE("context", "event");] + )], + [AC_MSG_RESULT(yes); have_sdt=yes; AC_DEFINE([ENABLE_TRACING], [1], [Define to 1 to enable eBPF user static defined tracepoints])], + [AC_MSG_RESULT(no); have_sdt=no;] + ) fi dnl Check for libminiupnpc (optional)