vlib: add a wasm module, implementing a pure V webassembly seralisation library (#17909)

examples/wasm_codegen/control_flow.v

@@ -0,0 +1,43 @@
+import wasm
+
+fn main() {
+	mut m := wasm.Module{}
+	mut bif := m.new_function('block_if', [.i32_t], [.i32_t])
+	{
+		loc := bif.new_local(.i32_t)
+
+		// loc = i32.const 10
+		bif.i32_const(10)
+		bif.local_set(loc)
+
+		blk := bif.c_block([], [])
+		{
+			// if argument[0], break
+			bif.local_get(0)
+			bif.c_br_if(blk)
+			// loc = i32.const 11
+			bif.i32_const(11)
+			bif.local_set(loc)
+		}
+		bif.c_end(blk)
+
+		// return loc
+		bif.local_get(loc)
+	}
+	m.commit(bif, true)
+	mut ifexpr := m.new_function('if_expr', [.i32_t], [.i64_t])
+	{
+		ifexpr.local_get(0)
+		ifexpr.c_if([], [.i64_t])
+		{
+			ifexpr.i64_const(5000)
+		}
+		ifexpr.c_else()
+		{
+			ifexpr.i64_const(-5000)
+		}
+		ifexpr.c_end_if()
+	}
+	m.commit(ifexpr, true)
+	print(m.compile().bytestr())
+}