llvm: implement translation of global variables.

_examples/misc/native_test.wa

@@ -33,13 +33,18 @@ fn main {
   test_struct1(13, 1, 0)
   test_struct1(2, 1, 0)
 
-  test_pointer()
-
   test_convert0()
   test_convert1()
   test_convert2()
   test_convert3()
 
+  test_global_consts()
+  test_global_variables_0()
+  test_global_variables_1()
+
+  test_pointer(1)
+  test_pointer(-1)
+
   bye()
 }
 
@@ -166,23 +171,6 @@ fn test_struct1(a int, b int, c int) {
   }
 }
 
-fn test_pointer() {
-  p := new_int()
-  println(*p)
-  set_int(p)
-  println(*p)
-}
-
-fn new_int() *i32 {
-  var i i32
-  i = 42
-  return &i
-}
-
-fn set_int(p *i32) {
-  *p = 13
-}
-
 fn convert_i32_to_i16(a i32) i16 {
   return i16(a)
 }
@@ -251,3 +239,57 @@ fn test_convert3() {
 fn test_print(a i16, b u16, c i8, d u8, e f32) {
   println(a, ", ", b, ", ", c, ", ", d, ", ", e/2)
 }
+
+const gbegin = 10
+const gend = 20
+
+fn test_global_consts() {
+  for i := gbegin; i < gend; i++ {
+    println(i, " - ", gbegin, " = ", i - gbegin)
+  }
+}
+
+type ty0 struct {
+  v0 int
+  v1 float64
+}
+var gv0 ty0 = ty0{5555, 3.1415926}
+var gv1 [4]int = [4]int{81, 82, 17, 76}
+
+fn test_global_variables_0() {
+  println("gv0: {", gv0.v0, ", ", gv0.v1, "}")
+  println("gv1: {", gv1[0], ", ", gv1[1], ", ", gv1[2], ", ", gv1[3], "}")
+}
+
+fn test_global_variables_1() {
+  gv0.v0 = 8888
+  gv0.v1 = 2.71828
+  gv1[0] += 2
+  gv1[1] += 3
+  gv1[2] += 4
+  gv1[3] += 5
+  println("gv0: {", gv0.v0, ", ", gv0.v1, "}")
+  println("gv1: {", gv1[0], ", ", gv1[1], ", ", gv1[2], ", ", gv1[3], "}")
+}
+
+var gint0 int = 100
+var gint1 int = 200
+
+fn get_int_addr(a int) *int {
+  if a > 0 {
+    return &gint0
+  } else {
+    return &gint1
+  }
+}
+
+fn set_int(a *int) {
+  *a += 10
+}
+
+fn test_pointer(a int) {
+  println(gint0, ", ", gint1)
+  p := get_int_addr(a)
+  set_int(p)
+  println(gint0, ", ", gint1)
+}

internal/backends/compiler_llvm/compile.go

@@ -71,12 +71,21 @@ func (p *Compiler) compilePackage() error {
 		}
 	}
 
+	// Emit all global variables.
+	for _, gv := range gs {
+		p.output.WriteString("@")
+		p.output.WriteString(getNormalName(gv.Name()))
+		p.output.WriteString(" = global ")
+		tys := getTypeStr(gv.Type(), p.target)
+		p.output.WriteString(tys[0:(len(tys) - 1)])
+		p.output.WriteString(" zeroinitializer\n")
+	}
+	if len(gs) > 0 {
+		p.output.WriteString("\n")
+	}
+
 	// Generate LLVM-IR for each global function.
 	for _, v := range fns {
-		// TODO: Support the builtin function 'init'.
-		if v.Name() == "init" {
-			continue
-		}
 		if err := p.compileFunction(v); err != nil {
 			return err
 		}

internal/backends/compiler_llvm/compile_function.go

@@ -46,6 +46,13 @@ func (p *Compiler) compileFunction(fn *ssa.Function) error {
 	}
 	p.output.WriteString(") {\n")
 
+	// Initialize all global variables at the beginning of the main function.
+	if fn.Name() == "main" {
+		p.output.WriteString("__basic_block_init:\n")
+		p.output.WriteString("  call void @init()\n")
+		p.output.WriteString("  br label %__basic_block_0\n\n")
+	}
+
 	// Translate Go SSA intermediate instructions.
 	for i, b := range fn.Blocks {
 		p.output.WriteString(fmt.Sprintf("__basic_block_%d:\n", i))

internal/backends/compiler_llvm/utils.go

@@ -262,7 +262,16 @@ func getValueStr(val ssa.Value) string {
 	case *ssa.Parameter:
 		return "%" + val.Name()
 
+	case *ssa.Global:
+		return "@" + getNormalName(val.Name())
+
 	default:
 		return "%" + val.Name()
 	}
 }
+
+func getNormalName(name string) string {
+	name = strings.ReplaceAll(name, ".", "__")
+	name = strings.ReplaceAll(name, "$", "___")
+	return name
+}