runtime: MakeMap

ssa/expr.go

@@ -35,6 +35,8 @@ type Expr struct {
 	Type
 }
 
+var Nil Expr // Zero value is a nil Expr
+
 // IsNil checks if the expression is nil or not.
 func (v Expr) IsNil() bool {
 	return v.Type == nil
@@ -477,6 +479,31 @@ func (b Builder) Slice(x, low, high, max Expr) (ret Expr) {
 
 // -----------------------------------------------------------------------------
 
+// The MakeMap instruction creates a new hash-table-based map object
+// and yields a value of kind map.
+//
+// t is a (possibly named) *types.Map.
+//
+// Pos() returns the ast.CallExpr.Lparen, if created by make(map), or
+// the ast.CompositeLit.Lbrack if created by a literal.
+//
+// Example printed form:
+//
+//	t1 = make map[string]int t0
+//	t1 = make StringIntMap t0
+func (b Builder) MakeMap(t Type, nReserve Expr) (ret Expr) {
+	if debugInstr {
+		log.Printf("MakeMap %v, %v\n", t, nReserve.impl)
+	}
+	pkg := b.fn.pkg
+	ret.Type = t
+	ret.impl = b.InlineCall(pkg.rtFunc("MakeSmallMap")).impl
+	// TODO(xsw): nReserve
+	return
+}
+
+// -----------------------------------------------------------------------------
+
 // The Alloc instruction reserves space for a variable of the given type,
 // zero-initializes it, and yields its address.
 //

ssa/package.go

@@ -117,6 +117,7 @@ type aProgram struct {
 	rtStringTy llvm.Type
 	rtIfaceTy  llvm.Type
 	rtSliceTy  llvm.Type
+	rtMapTy    llvm.Type
 
 	anyTy     Type
 	voidTy    Type
@@ -184,6 +185,13 @@ func (p Program) rtIface() llvm.Type {
 	return p.rtIfaceTy
 }
 
+func (p Program) rtMap() llvm.Type {
+	if p.rtMapTy.IsNil() {
+		p.rtMapTy = p.rtType("Map").ll
+	}
+	return p.rtMapTy
+}
+
 func (p Program) rtSlice() llvm.Type {
 	if p.rtSliceTy.IsNil() {
 		p.rtSliceTy = p.rtType("Slice").ll

ssa/stmt_builder.go

@@ -126,4 +126,20 @@ func (b Builder) If(cond Expr, thenb, elseb BasicBlock) {
 	b.impl.CreateCondBr(cond.impl, thenb.impl, elseb.impl)
 }
 
+// The MapUpdate instruction updates the association of Map[Key] to
+// Value.
+//
+// Pos() returns the ast.KeyValueExpr.Colon or ast.IndexExpr.Lbrack,
+// if explicit in the source.
+//
+// Example printed form:
+//
+//	t0[t1] = t2
+func (b Builder) MapUpdate(m, k, v Expr) {
+	if debugInstr {
+		log.Printf("MapUpdate %v[%v] = %v\n", m.impl, k.impl, v.impl)
+	}
+	panic("todo")
+}
+
 // -----------------------------------------------------------------------------

ssa/type.go

@@ -256,6 +256,7 @@ func (p Program) toLLVMType(typ types.Type) Type {
 	case *types.Slice:
 		return &aType{p.rtSlice(), typ, vkInvalid}
 	case *types.Map:
+		return &aType{p.rtMap(), typ, vkInvalid}
 	case *types.Struct:
 		return p.toLLVMStruct(t)
 	case *types.Named: