From 425253e2cd64e23585f557bfa82789a5208d06e1 Mon Sep 17 00:00:00 2001
From: David Goldblatt <davidgoldblatt@fb.com>
Date: Fri, 21 Apr 2017 13:47:49 -0700
Subject: [PATCH] Enable -Wundef, when supported.

This can catch bugs in which one header defines a numeric constant, and another
uses it without including the defining header. Undefined preprocessor symbols
expand to '0', so that this will compile fine, silently doing the math wrong.
---
 configure.ac                                          |  5 ++++-
 include/jemalloc/internal/jemalloc_internal_defs.h.in |  3 +++
 include/jemalloc/internal/jemalloc_preamble.h.in      |  1 +
 src/jemalloc.c                                        | 10 +---------
 src/nstime.c                                          |  6 +++---
 5 files changed, 12 insertions(+), 13 deletions(-)

diff --git a/configure.ac b/configure.ac
index 73450b4c..0a717255 100644
--- a/configure.ac
+++ b/configure.ac
@@ -241,6 +241,7 @@ if test "x$GCC" = "xyes" ; then
   JE_CFLAGS_ADD([-Wall])
   JE_CFLAGS_ADD([-Wshorten-64-to-32])
   JE_CFLAGS_ADD([-Wsign-compare])
+  JE_CFLAGS_ADD([-Wundef])
   JE_CFLAGS_ADD([-pipe])
   JE_CFLAGS_ADD([-g3])
 elif test "x$je_cv_msvc" = "xyes" ; then
@@ -824,7 +825,9 @@ else
   JEMALLOC_PREFIX="je_"
 fi]
 )
-if test "x$JEMALLOC_PREFIX" != "x" ; then
+if test "x$JEMALLOC_PREFIX" = "x" ; then
+  AC_DEFINE([JEMALLOC_IS_MALLOC])
+else
   JEMALLOC_CPREFIX=`echo ${JEMALLOC_PREFIX} | tr "a-z" "A-Z"`
   AC_DEFINE_UNQUOTED([JEMALLOC_PREFIX], ["$JEMALLOC_PREFIX"])
   AC_DEFINE_UNQUOTED([JEMALLOC_CPREFIX], ["$JEMALLOC_CPREFIX"])
diff --git a/include/jemalloc/internal/jemalloc_internal_defs.h.in b/include/jemalloc/internal/jemalloc_internal_defs.h.in
index 44896ae2..1bec2c93 100644
--- a/include/jemalloc/internal/jemalloc_internal_defs.h.in
+++ b/include/jemalloc/internal/jemalloc_internal_defs.h.in
@@ -312,4 +312,7 @@
 /* config.malloc_conf options string. */
 #undef JEMALLOC_CONFIG_MALLOC_CONF
 
+/* If defined, jemalloc takes the malloc/free/etc. symbol names. */
+#undef JEMALLOC_IS_MALLOC
+
 #endif /* JEMALLOC_INTERNAL_DEFS_H_ */
diff --git a/include/jemalloc/internal/jemalloc_preamble.h.in b/include/jemalloc/internal/jemalloc_preamble.h.in
index dc21cf49..79827fc4 100644
--- a/include/jemalloc/internal/jemalloc_preamble.h.in
+++ b/include/jemalloc/internal/jemalloc_preamble.h.in
@@ -10,6 +10,7 @@
 
 #define JEMALLOC_NO_DEMANGLE
 #ifdef JEMALLOC_JET
+#  undef JEMALLOC_IS_MALLOC
 #  define JEMALLOC_N(n) jet_##n
 #  include "jemalloc/internal/public_namespace.h"
 #  define JEMALLOC_NO_RENAME
diff --git a/src/jemalloc.c b/src/jemalloc.c
index 27a9fd7b..de858e36 100644
--- a/src/jemalloc.c
+++ b/src/jemalloc.c
@@ -2285,15 +2285,7 @@ je_valloc(size_t size) {
 }
 #endif
 
-/*
- * is_malloc(je_malloc) is some macro magic to detect if jemalloc_defs.h has
- * #define je_malloc malloc
- */
-#define malloc_is_malloc 1
-#define is_malloc_(a) malloc_is_ ## a
-#define is_malloc(a) is_malloc_(a)
-
-#if ((is_malloc(je_malloc) == 1) && defined(JEMALLOC_GLIBC_MALLOC_HOOK))
+#if defined(JEMALLOC_IS_MALLOC) && defined(JEMALLOC_GLIBC_MALLOC_HOOK)
 /*
  * glibc provides the RTLD_DEEPBIND flag for dlopen which can make it possible
  * to inconsistently reference libc's malloc(3)-compatible functions
diff --git a/src/nstime.c b/src/nstime.c
index 9f5d192d..20c00422 100644
--- a/src/nstime.c
+++ b/src/nstime.c
@@ -96,7 +96,7 @@ nstime_get(nstime_t *time) {
 
 	nstime_init(time, ticks_100ns * 100);
 }
-#elif JEMALLOC_HAVE_CLOCK_MONOTONIC_COARSE
+#elif defined(JEMALLOC_HAVE_CLOCK_MONOTONIC_COARSE)
 #  define NSTIME_MONOTONIC true
 static void
 nstime_get(nstime_t *time) {
@@ -105,7 +105,7 @@ nstime_get(nstime_t *time) {
 	clock_gettime(CLOCK_MONOTONIC_COARSE, &ts);
 	nstime_init2(time, ts.tv_sec, ts.tv_nsec);
 }
-#elif JEMALLOC_HAVE_CLOCK_MONOTONIC
+#elif defined(JEMALLOC_HAVE_CLOCK_MONOTONIC)
 #  define NSTIME_MONOTONIC true
 static void
 nstime_get(nstime_t *time) {
@@ -114,7 +114,7 @@ nstime_get(nstime_t *time) {
 	clock_gettime(CLOCK_MONOTONIC, &ts);
 	nstime_init2(time, ts.tv_sec, ts.tv_nsec);
 }
-#elif JEMALLOC_HAVE_MACH_ABSOLUTE_TIME
+#elif defined(JEMALLOC_HAVE_MACH_ABSOLUTE_TIME)
 #  define NSTIME_MONOTONIC true
 static void
 nstime_get(nstime_t *time) {