From b841fbd417873fda16fbf42d5c6a52cccef384dc Mon Sep 17 00:00:00 2001
From: ian <ian@138bc75d-0d04-0410-961f-82ee72b054a4>
Date: Fri, 12 Feb 2016 22:10:09 +0000
Subject:     runtime: For c-archive/c-shared, install signal handlers
 synchronously.

    This is a port of https://golang.org/cl/18150 to the gccgo runtime.

    The previous behaviour of installing the signal handlers in a separate
    thread meant that Go initialization raced with non-Go initialization if
    the non-Go initialization also wanted to install signal handlers.  Make
    installing signal handlers synchronous so that the process-wide behavior
    is predictable.

    Reviewed-on: https://go-review.googlesource.com/19494


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@233393 138bc75d-0d04-0410-961f-82ee72b054a4
---
 gcc/go/gofrontend/MERGE     |  2 +-
 libgo/runtime/go-libmain.c  |  6 ++++--
 libgo/runtime/proc.c        |  2 +-
 libgo/runtime/runtime.h     |  2 +-
 libgo/runtime/signal_unix.c | 10 +++++++++-
 5 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/gcc/go/gofrontend/MERGE b/gcc/go/gofrontend/MERGE
index fee516838cb..228dfc1360a 100644
--- a/gcc/go/gofrontend/MERGE
+++ b/gcc/go/gofrontend/MERGE
@@ -1,4 +1,4 @@
-28a9dfbc3cda0bf7fd4f3fb1506c547f6cdf41a5
+22278c6e8ce3982b09111183bc6addf0184bef1f
 
 The first line of this file holds the git revision number of the last
 merge done from the gofrontend repository.
diff --git a/libgo/runtime/go-libmain.c b/libgo/runtime/go-libmain.c
index f578aab43b7..6884f3a5f56 100644
--- a/libgo/runtime/go-libmain.c
+++ b/libgo/runtime/go-libmain.c
@@ -59,6 +59,10 @@ initfn (int argc, char **argv, char** env __attribute__ ((unused)))
   struct args *a;
   pthread_t tid;
 
+  runtime_isarchive = true;
+
+  runtime_initsig(true);
+
   a = (struct args *) malloc (sizeof *a);
   if (a == NULL)
     die ("malloc", errno);
@@ -88,8 +92,6 @@ gostart (void *arg)
 {
   struct args *a = (struct args *) arg;
 
-  runtime_isarchive = true;
-
   if (runtime_isstarted)
     return NULL;
   runtime_isstarted = true;
diff --git a/libgo/runtime/proc.c b/libgo/runtime/proc.c
index cd926b4ea62..9ba199b8cae 100644
--- a/libgo/runtime/proc.c
+++ b/libgo/runtime/proc.c
@@ -1093,7 +1093,7 @@ runtime_mstart(void* mp)
 			runtime_newextram();
 			runtime_needextram = 0;
 		}
-		runtime_initsig();
+		runtime_initsig(false);
 	}
 	
 	if(m->mstartfn)
diff --git a/libgo/runtime/runtime.h b/libgo/runtime/runtime.h
index 34143e9a256..73c46e9117f 100644
--- a/libgo/runtime/runtime.h
+++ b/libgo/runtime/runtime.h
@@ -550,7 +550,7 @@ void*	runtime_mal(uintptr);
 String	runtime_gostring(const byte*);
 String	runtime_gostringnocopy(const byte*);
 void	runtime_schedinit(void);
-void	runtime_initsig(void);
+void	runtime_initsig(bool);
 void	runtime_sigenable(uint32 sig);
 void	runtime_sigdisable(uint32 sig);
 void	runtime_sigignore(uint32 sig);
diff --git a/libgo/runtime/signal_unix.c b/libgo/runtime/signal_unix.c
index 20289335f8d..5bee0d2a706 100644
--- a/libgo/runtime/signal_unix.c
+++ b/libgo/runtime/signal_unix.c
@@ -13,11 +13,16 @@
 extern SigTab runtime_sigtab[];
 
 void
-runtime_initsig(void)
+runtime_initsig(bool preinit)
 {
 	int32 i;
 	SigTab *t;
 
+	// For c-archive/c-shared this is called by go-libmain.c with
+	// preinit == true.
+	if(runtime_isarchive && !preinit)
+		return;
+
 	// First call: basic setup.
 	for(i = 0; runtime_sigtab[i].sig != -1; i++) {
 		t = &runtime_sigtab[i];
@@ -37,6 +42,9 @@ runtime_initsig(void)
 			}
 		}
 
+		if(runtime_isarchive && (t->flags&SigPanic) == 0)
+			continue;
+
 		t->flags |= SigHandling;
 		runtime_setsig(i, runtime_sighandler, true);
 	}
-- 
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