libgo patch committed: NetBSD fix

libgo patch committed: NetBSD fix

[Ian Lance Taylor]

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This patch from Shenghou Ma fixes gccgo on libgo by not losing the TLS
pointer.  This works around what I would describe as a bug in the NetBSD
libc.  Bootstrapped on x86_64-unknown-linux-gnu, not that that proves
much.  Committed to mainline.

Ian


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diff -r df61836f495f libgo/runtime/proc.c
--- a/libgo/runtime/proc.c	Mon Nov 05 09:36:01 2012 -0800
+++ b/libgo/runtime/proc.c	Mon Nov 05 09:37:21 2012 -0800
@@ -82,7 +82,7 @@
 {
 }
 
-# else
+#else
 
 # if defined(__x86_64__) && defined(__sun__)
 
@@ -110,6 +110,28 @@
 	c->uc_mcontext.gregs[REG_FSBASE] = fs;
 }
 
+# elif defined(__NetBSD__)
+
+// NetBSD has a bug: setcontext clobbers tlsbase, we need to save
+// and restore it ourselves.
+
+static __thread __greg_t tlsbase;
+
+static inline void
+initcontext(void)
+{
+	ucontext_t c;
+
+	getcontext(&c);
+	tlsbase = c.uc_mcontext._mc_tlsbase;
+}
+
+static inline void
+fixcontext(ucontext_t* c)
+{
+	c->uc_mcontext._mc_tlsbase = tlsbase;
+}
+
 # else
 
 #  error unknown case for SETCONTEXT_CLOBBERS_TLS