diff --git a/.gitmodules b/.gitmodules
index 9f18be11e..e8f7ee3c2 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -5,3 +5,12 @@
 [submodule "cxxopts"]
 	path = libs/cxxopts
 	url = https://github.com/jarro2783/cxxopts
+[submodule "slang"]
+	path = libs/slang
+	url = https://github.com/MikePopoloski/slang
+[submodule "fmt"]
+	path = libs/fmt
+	url = https://github.com/fmtlib/fmt
+[submodule "yosys-slang"]
+	path = frontends/slang/lib
+	url = https://github.com/povik/yosys-slang
diff --git a/frontends/slang/lib b/frontends/slang/lib
new file mode 160000
index 000000000..325153096
--- /dev/null
+++ b/frontends/slang/lib
@@ -0,0 +1 @@
+Subproject commit 3251530961e0e8a8054098c9bb8376474958944a
diff --git a/libs/fmt b/libs/fmt
new file mode 160000
index 000000000..553ec11ec
--- /dev/null
+++ b/libs/fmt
@@ -0,0 +1 @@
+Subproject commit 553ec11ec06fbe0beebfbb45f9dc3c9eabd83d28
diff --git a/libs/slang b/libs/slang
new file mode 160000
index 000000000..f04e81565
--- /dev/null
+++ b/libs/slang
@@ -0,0 +1 @@
+Subproject commit f04e81565793c768b747a8fd058f3e7aeceee1b5