libphobos: Fix segfault in runtime caused by unexpected GC of TLS data.

libphobos/ChangeLog:

2019-04-25  Iain Buclaw  <ibuclaw@gdcproject.org>

	PR d/90250
	* libdruntime/gcc/sections/elf_shared.d (initTLSRanges): Populate
	_tlsRanges in every startup thread.
	* testsuite/libphobos.thread/thread.exp: Load libphobos-dg.exp.
	* testsuite/libphobos.thread/tlsgc_sections.d: New test.

From-SVN: r270576

libphobos/ChangeLog

+2019-04-25  Iain Buclaw  <ibuclaw@gdcproject.org>
+
+	PR d/90250
+	* libdruntime/gcc/sections/elf_shared.d (initTLSRanges): Populate
+	_tlsRanges in every startup thread.
+	* testsuite/libphobos.thread/thread.exp: Load libphobos-dg.exp.
+	* testsuite/libphobos.thread/tlsgc_sections.d: New test.
+
 2019-04-25  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>
 
 	* m4/druntime/cpu.m4 (DRUNTIME_CPU_SOURCES): Quote brackets.

libphobos/libdruntime/gcc/sections/elf_shared.d

@@ -308,7 +308,13 @@ else
      */
     Array!(void[])* initTLSRanges() nothrow @nogc
     {
-        return &_tlsRanges();
+        auto rngs = &_tlsRanges();
+        if (rngs.empty)
+        {
+            foreach (ref pdso; _loadedDSOs)
+                rngs.insertBack(pdso.tlsRange());
+        }
+        return rngs;
     }
 
     void finiTLSRanges(Array!(void[])* rngs) nothrow @nogc

libphobos/testsuite/libphobos.thread/thread.exp

@@ -14,6 +14,8 @@
 # along with GCC; see the file COPYING3.  If not see
 # <http://www.gnu.org/licenses/>.
 
+load_lib libphobos-dg.exp
+
 # Initialize dg.
 dg-init
 

libphobos/testsuite/libphobos.thread/tlsgc_sections.d

+final class Class
+{
+    // This gets triggered although the instance always stays referenced.
+    ~this()
+    {
+        import core.stdc.stdlib;
+        abort();
+    }
+}
+
+Class obj;
+
+static this()
+{
+    obj = new Class;
+}
+
+static ~this()
+{
+    // Free without destruction to avoid triggering abort()
+    import core.memory;
+    GC.free(cast(void*)obj);
+}
+
+void doit()
+{
+    foreach (i; 0 .. 10_000)
+        new ubyte[](100_000);
+}
+
+void main()
+{
+    import core.thread;
+    auto t = new Thread(&doit);
+    t.start();
+
+    // This triggers the GC that frees the still referenced Class instance.
+    doit();
+}