fix Issue 17352 - Internal error: ddmd/backend/elfobj.c 1739 on dupli…

…cate definition

src/ddmd/backend/elfobj.c

@@ -1736,12 +1736,16 @@ STATIC void setup_comdat(Symbol *s)
         const char *p = cpp_mangle(s);
         // Create a section for the comdat symbol with the SHF_GROUP bit set
         s->Sseg = ElfObj::getsegment(".text.", p, SHT_PROGBITS, SHF_ALLOC|SHF_EXECINSTR|SHF_GROUP, align);
-        /* Workaround https://issues.dlang.org/show_bug.cgi?id=17339, there was
-         * a previous instance with the same mangling.  Leave the section group
-         * empty and reuse the existing one. */
-        const bool issue17339 = MAP_SEG2SECIDX(s->Sseg) < groupsecidx;
+        /* If that text section already existed, we've hit one of the few occurences of different
+         * symbols with identical mangling. This should not happen, but as a workaround we leave the
+         * just created section group empty and reuse the existing one.  Also see
+         * https://issues.dlang.org/show_bug.cgi?id=17352,
+         * https://issues.dlang.org/show_bug.cgi?id=14831, and
+         * https://issues.dlang.org/show_bug.cgi?id=17339.
+        */
+        const bool collidingSection = MAP_SEG2SECIDX(s->Sseg) < groupsecidx;
         // add to section group
-        if (!issue17339)
+        if (!collidingSection)
             SegData[groupseg]->SDbuf->write32(MAP_SEG2SECIDX(s->Sseg));
 
         // Create a weak symbol for the comdat
@@ -1757,7 +1761,7 @@ STATIC void setup_comdat(Symbol *s)
 
         if (s->Salignment > align)
             SegData[s->Sseg]->SDalignment = s->Salignment;
-        if (issue17339)
+        if (collidingSection)
         {
             // existing section symbol and associated group
             assert(SegData[s->Sseg]->SDsym);

test/compilable/test17352.d

@@ -0,0 +1,18 @@
+// https://issues.dlang.org/show_bug.cgi?id=17352
+void bug(Args...)()
+{
+}
+
+void test(bool coin)
+{
+    if (coin)
+    {
+        string foobar;
+        bug!foobar();
+    }
+    else
+    {
+        string foobar;
+        bug!foobar();
+    }
+}