print-c-backtrace-on-memlog.patch

--- perl-5.26.2-orig-util.c	2018-09-20 18:00:03.455252440 +0100
+++ perl-5.26.2-edited-util.c	2018-09-20 18:03:31.026429614 +0100
@@ -4814,7 +4814,7 @@
 /* -DPERL_MEM_LOG_SPRINTF_BUF_SIZE=X: size of a (stack-allocated) buffer
  * the Perl_mem_log_...() will use (either via sprintf or snprintf).
  */
-#define PERL_MEM_LOG_SPRINTF_BUF_SIZE 128
+#define PERL_MEM_LOG_SPRINTF_BUF_SIZE 256
 
 /* -DPERL_MEM_LOG_FD=N: the file descriptor the Perl_mem_log_...()
  * writes to.  In the default logger, this is settable at runtime.
@@ -4920,6 +4920,24 @@
 		len = 0;
 	    }
 	    PERL_UNUSED_RESULT(PerlLIO_write(fd, buf, len));
+            if(strchr(pmlenv,'c') && (mlt == MLT_NEW_SV)) {
+		Perl_c_backtrace *bt = Perl_get_c_backtrace(aTHX_ 3, 3);
+		Perl_c_backtrace_frame *frame;
+		int i;
+		for (i = 0, frame = bt->frame_info;
+			i < bt->header.frame_count;
+			i++, frame++) {
+		    len = my_snprintf(buf, sizeof(buf),
+			    "  frame[%d]: %p %s at %s +0x%lx\n",
+			    i,
+			    frame->addr,
+			    frame->symbol_name_size && frame->symbol_name_offset ? (char *)bt + frame->symbol_name_offset : "-",
+			    frame->object_name_size && frame->object_name_offset ? (char *)bt + frame->object_name_offset : "?",
+			    frame->addr - frame->object_base_addr);
+		    PerlLIO_write(fd, buf, len);
+		}
+		Perl_free_c_backtrace(aTHX_ bt);
+	    }
 	}
     }
 }