printer: shorten text size when argsize is zero

printer/goasm_test.go

@@ -0,0 +1,63 @@
+package printer_test
+
+import (
+	"testing"
+
+	"github.com/mmcloughlin/avo/build"
+	"github.com/mmcloughlin/avo/printer"
+	"github.com/mmcloughlin/avo/reg"
+)
+
+func TestBasic(t *testing.T) {
+	ctx := build.NewContext()
+	ctx.Function("add")
+	ctx.SignatureExpr("func(x, y uint64) uint64")
+	x := ctx.Load(ctx.Param("x"), reg.RAX)
+	y := ctx.Load(ctx.Param("y"), reg.R9)
+	ctx.ADDQ(x, y)
+	ctx.Store(y, ctx.ReturnIndex(0))
+	ctx.RET()
+
+	AssertPrintsLines(t, ctx, printer.NewGoAsm, []string{
+		"// Code generated by avo. DO NOT EDIT.",
+		"",
+		"#include \"textflag.h\"",
+		"",
+		"// func add(x uint64, y uint64) uint64",
+		"TEXT ·add(SB), 0, $0-24",
+		"\tMOVQ\tx(FP), AX",
+		"\tMOVQ\ty+8(FP), R9",
+		"\tADDQ\tAX, R9",
+		"\tMOVQ\tR9, ret+16(FP)",
+		"\tRET",
+		"",
+	})
+}
+
+func TestTextSize(t *testing.T) {
+	ctx := build.NewContext()
+
+	ctx.Function("noargs")
+	ctx.SignatureExpr("func()")
+	ctx.AllocLocal(16)
+	ctx.RET()
+
+	ctx.Function("withargs")
+	ctx.SignatureExpr("func(x, y uint64) uint64")
+	ctx.RET()
+
+	AssertPrintsLines(t, ctx, printer.NewGoAsm, []string{
+		"// Code generated by avo. DO NOT EDIT.",
+		"",
+		"#include \"textflag.h\"",
+		"",
+		"// func noargs()",
+		"TEXT ·noargs(SB), 0, $16", // expect only the frame size
+		"\tRET",
+		"",
+		"// func withargs(x uint64, y uint64) uint64",
+		"TEXT ·withargs(SB), 0, $0-24", // expect both frame size and argument size
+		"\tRET",
+		"",
+	})
+}