From ea0a1df3a11a47a5a3eebc68e721986ba748bf11 Mon Sep 17 00:00:00 2001
From: Jason Volk <jason@zemos.net>
Date: Wed, 3 Jul 2019 14:31:05 -0700
Subject: [PATCH] configure: Add options for third-party allocator
 selection/deselection and inclusion.

---
 configure.ac             | 60 ++++++++++++++++++++++++++++++++++++++--
 construct/Makefile.am    |  3 ++
 doc/BUILD.md             | 11 ++++++++
 include/ircd/Makefile.am |  1 +
 ircd/Makefile.am         |  3 ++
 5 files changed, 76 insertions(+), 2 deletions(-)

diff --git a/configure.ac b/configure.ac
index ffadf8e2b..55925edb7 100644
--- a/configure.ac
+++ b/configure.ac
@@ -440,6 +440,22 @@ AM_COND_IF([UNTUNED],
 	CXXFLAGS+=""
 ])
 
+dnl
+dnl Disable third-party allocators
+dnl
+
+AC_MSG_CHECKING(whether to prevent available third-party allocator libraries from being used)
+AC_ARG_ENABLE(allocators, AC_HELP_STRING([--disable-alloc-libs], [Disable third-party dynamic memory libraries (jemalloc/tcmalloc/etc)]),
+[
+	use_alloc_libs="no"
+	AC_MSG_RESULT([yes])
+], [
+	use_alloc_libs="yes"
+	AC_MSG_RESULT([no])
+])
+
+AM_CONDITIONAL([ALLOC_LIBS], [[[[ "$use_alloc_libs" = "yes" ]]]])
+
 dnl  !!! Experimental !!!
 dnl
 dnl  Allows a signal handler to throw a C++ exception if the signal is from
@@ -1665,9 +1681,48 @@ dnl
 RB_CHK_SYSHEADER(jemalloc/jemalloc.h, [JEMALLOC_H])
 AC_CHECK_LIB(jemalloc, malloc,
 [
-	jemalloc="yes"
+	have_jemalloc="yes"
 ], [
-	jemalloc="no"
+	have_jemalloc="no"
+])
+
+AC_MSG_CHECKING(whether to enable use of jemalloc)
+AC_ARG_ENABLE(jemalloc, AC_HELP_STRING([--enable-jemalloc], [Use jemalloc as third-party dynamic memory manager.]),
+[
+	use_jemalloc="yes"
+	AC_MSG_RESULT([yes])
+], [
+	use_jemalloc="no"
+	AC_MSG_RESULT([no])
+])
+
+AM_CONDITIONAL([JEMALLOC], [test "x$have_jemalloc" = "xyes" && test "x$use_jemalloc" = "xyes" ])
+
+dnl
+dnl
+dnl Select a third-party allocator
+dnl
+dnl
+
+AC_SUBST(MALLOC_CPPFLAGS)
+AC_SUBST(MALLOC_CXXFLAGS)
+AC_SUBST(MALLOC_LDFLAGS)
+AC_SUBST(MALLOC_LIBS)
+alloc_lib="standard"
+
+dnl ALLOC_LIBS true unless --disable-alloc-libs configured
+AM_COND_IF([ALLOC_LIBS],
+[
+	AM_COND_IF([JEMALLOC],
+	[
+		alloc_lib="jemalloc"
+		MALLOC_LIBS+=" -ljemalloc"
+		AC_DEFINE(IRCD_ALLOCATOR_USE_JEMALLOC, 1, [Use jemalloc as the allocator])
+	], [
+		AC_DEFINE(IRCD_ALLOCATOR_USE_DEFAULT, 1, [Use the default allocator])
+	])
+], [
+	AC_DEFINE(IRCD_ALLOCATOR_USE_DEFAULT, 1, [Use the default allocator])
 ])
 
 dnl
@@ -1839,6 +1894,7 @@ echo "Link-time optimized ............... $lto"
 echo "Optimization level ................ $optimize_level"
 echo "Generic binary .................... $enable_generic"
 echo "Untuned binary .................... $enable_untuned"
+echo "Memory allocator .................. $alloc_lib"
 echo "Logging level ..................... $LOG_LEVEL"
 echo "Installing into ................... $prefix"
 echo
diff --git a/construct/Makefile.am b/construct/Makefile.am
index 213730591..434a8f276 100644
--- a/construct/Makefile.am
+++ b/construct/Makefile.am
@@ -17,6 +17,7 @@ AM_CPPFLAGS = \
 	@SNAPPY_CPPFLAGS@ \
 	@LZ4_CPPFLAGS@ \
 	@Z_CPPFLAGS@ \
+	@MALLOC_CPPFLAGS@ \
 	@EXTRA_CPPFLAGS@ \
 	###
 
@@ -66,6 +67,7 @@ construct_LDFLAGS = \
 	@SNAPPY_LDFLAGS@ \
 	@LZ4_LDFLAGS@ \
 	@Z_LDFLAGS@ \
+	@MALLOC_LDFLAGS@ \
 	###
 
 construct_LDADD = \
@@ -80,6 +82,7 @@ construct_LDADD = \
 	@SNAPPY_LIBS@ \
 	@LZ4_LIBS@ \
 	@Z_LIBS@ \
+	@MALLOC_LIBS@ \
 	@EXTRA_LIBS@ \
 	###
 
diff --git a/doc/BUILD.md b/doc/BUILD.md
index 78061a6ac..2cc6632bb 100644
--- a/doc/BUILD.md
+++ b/doc/BUILD.md
@@ -111,6 +111,17 @@ This manually applies full release-mode optimizations even when using
 `--enable-debug`. Implied when not in debug mode.
 
 
+##### Disable third-party dynamic allocator libraries
+
+```
+--disable-alloc-libs
+```
+`./configure` will detect alternative `malloc()` implementations found in
+libraries installed on the system (jemalloc/tcmalloc/etc). Construct developers
+may enable these to be configured by default, if detected. To always prevent
+any alternative to the default standard library allocator specify this option.
+
+
 ##### Logging level
 
 ```
diff --git a/include/ircd/Makefile.am b/include/ircd/Makefile.am
index 9cdab8a14..f7540bd03 100644
--- a/include/ircd/Makefile.am
+++ b/include/ircd/Makefile.am
@@ -12,6 +12,7 @@ AM_CPPFLAGS = \
 	@SNAPPY_CPPFLAGS@ \
 	@LZ4_CPPFLAGS@ \
 	@Z_CPPFLAGS@ \
+	@MALLOC_CPPFLAGS@ \
 	@EXTRA_CPPFLAGS@ \
     ###
 
diff --git a/ircd/Makefile.am b/ircd/Makefile.am
index a7c05154b..2444357c3 100644
--- a/ircd/Makefile.am
+++ b/ircd/Makefile.am
@@ -27,6 +27,7 @@ AM_CPPFLAGS = \
 	@SNAPPY_CPPFLAGS@ \
 	@LZ4_CPPFLAGS@ \
 	@Z_CPPFLAGS@ \
+	@MALLOC_CPPFLAGS@ \
 	-include ircd/ircd.pic.h \
 	@EXTRA_CPPFLAGS@ \
 	###
@@ -86,6 +87,7 @@ libircd_la_LDFLAGS = \
 	@SNAPPY_LDFLAGS@ \
 	@LZ4_LDFLAGS@ \
 	@Z_LDFLAGS@ \
+	@MALLOC_LDFLAGS@ \
 	###
 
 libircd_la_LIBADD = \
@@ -99,6 +101,7 @@ libircd_la_LIBADD = \
 	@SNAPPY_LIBS@ \
 	@LZ4_LIBS@ \
 	@Z_LIBS@ \
+	@MALLOC_LIBS@ \
 	@EXTRA_LIBS@ \
 	###