From e9d2d6e08dcf6962aa7b2818389d9a6d451d7d14 Mon Sep 17 00:00:00 2001
From: Brian Norris <banorris@uci.edu>
Date: Thu, 4 Apr 2013 13:19:50 -0700
Subject: [PATCH] context: move Mac swapcontext() to separate compilation unit

We really don't want model_swapcontext() to ever be inlined on Mac OSX,
since this could potentially cause subtle getcontext()-related bugs to
resurface. Just make it a separate compilation unit (*.cc file).
---
 Makefile   |  3 ++-
 context.cc | 27 +++++++++++++++++++++++++++
 context.h  | 25 ++++++-------------------
 3 files changed, 35 insertions(+), 20 deletions(-)
 create mode 100644 context.cc

diff --git a/Makefile b/Makefile
index b653e769..5120cce8 100644
--- a/Makefile
+++ b/Makefile
@@ -3,7 +3,8 @@ include common.mk
 OBJECTS = libthreads.o schedule.o model.o threads.o librace.o action.o \
 	  nodestack.o clockvector.o main.o snapshot-interface.o cyclegraph.o \
 	  datarace.o impatomic.o cmodelint.o \
-	  snapshot.o malloc.o mymemory.o common.o mutex.o promise.o conditionvariable.o
+	  snapshot.o malloc.o mymemory.o common.o mutex.o promise.o conditionvariable.o \
+	  context.o
 
 CPPFLAGS += -Iinclude -I.
 LDFLAGS = -ldl -lrt -rdynamic
diff --git a/context.cc b/context.cc
new file mode 100644
index 00000000..b5ae0ba5
--- /dev/null
+++ b/context.cc
@@ -0,0 +1,27 @@
+#include "context.h"
+
+#ifdef MAC
+
+int model_swapcontext(ucontext_t *oucp, ucontext_t *ucp)
+{
+	/*
+	 * Mac OSX swapcontext() clobbers some registers, so use a hand-rolled
+	 * version with {get,set}context(). We can avoid the same problem
+	 * (where optimizations can break the following code) because we don't
+	 * statically link with the C library
+	 */
+
+	/* volatile, so that 'i' doesn't get promoted to a register */
+	volatile int i = 0;
+
+	getcontext(oucp);
+
+	if (i == 0) {
+		i = 1;
+		setcontext(ucp);
+	}
+
+	return 0;
+}
+
+#endif /* MAC */
diff --git a/context.h b/context.h
index 862cda5e..ea32d2f5 100644
--- a/context.h
+++ b/context.h
@@ -8,30 +8,17 @@
 
 #include <ucontext.h>
 
-static inline int model_swapcontext(ucontext_t *oucp, ucontext_t *ucp)
-{
 #ifdef MAC
-	/*
-	 * Mac OSX swapcontext() clobbers some registers, so use a hand-rolled
-	 * version with {get,set}context(). We can avoid the same problem
-	 * (where optimizations can break the following code) because we don't
-	 * statically link with the C library
-	 */
-
-	/* volatile, so that 'i' doesn't get promoted to a register */
-	volatile int i = 0;
 
-	getcontext(oucp);
+int model_swapcontext(ucontext_t *oucp, ucontext_t *ucp);
 
-	if (i == 0) {
-		i = 1;
-		setcontext(ucp);
-	}
+#else /* !MAC */
 
-	return 0;
-#else
+static inline int model_swapcontext(ucontext_t *oucp, ucontext_t *ucp)
+{
 	return swapcontext(oucp, ucp);
-#endif
 }
 
+#endif /* !MAC */
+
 #endif /* __CONTEXT_H__ */
-- 
2.34.1