cl: support llgo.cstr

cl/_testdata/cstr/in.go

@@ -0,0 +1,13 @@
+package main
+
+import _ "unsafe"
+
+//go:linkname cstr llgo.cstr
+func cstr(string) *int8
+
+//go:linkname printf C.printf
+func printf(format *int8, __llgo_va_list ...any)
+
+func main() {
+	printf(cstr("Hello, world\n"))
+}

cl/_testdata/cstr/out.ll

@@ -0,0 +1,26 @@
+; ModuleID = 'main'
+source_filename = "main"
+
+@"main.init$guard" = global ptr null
+
+define void @main.init() {
+_llgo_0:
+  %0 = load i1, ptr @"main.init$guard", align 1
+  br i1 %0, label %_llgo_2, label %_llgo_1
+
+_llgo_1:                                          ; preds = %_llgo_0
+  store i1 true, ptr @"main.init$guard", align 1
+  br label %_llgo_2
+
+_llgo_2:                                          ; preds = %_llgo_1, %_llgo_0
+  ret void
+}
+
+define void @main() {
+_llgo_0:
+  call void @main.init()
+  call void (ptr, ...) @printf([14 x i8] c"Hello, world\0A\00")
+  ret void
+}
+
+declare void @printf(ptr, ...)