feat:llgo.Asm

test:asm test with `nop`

cl/_testrt/asm/in.go

@@ -0,0 +1,10 @@
+package main
+
+import _ "unsafe"
+
+//go:linkname asm llgo.asm
+func asm(instruction string)
+
+func main() {
+	asm("nop")
+}

cl/_testrt/asm/out.ll

@@ -0,0 +1,23 @@
+; ModuleID = 'github.com/goplus/llgo/cl/_testrt/asm'
+source_filename = "github.com/goplus/llgo/cl/_testrt/asm"
+
+@"github.com/goplus/llgo/cl/_testrt/asm.init$guard" = global i1 false, align 1
+
+define void @"github.com/goplus/llgo/cl/_testrt/asm.init"() {
+_llgo_0:
+  %0 = load i1, ptr @"github.com/goplus/llgo/cl/_testrt/asm.init$guard", align 1
+  br i1 %0, label %_llgo_2, label %_llgo_1
+
+_llgo_1:                                          ; preds = %_llgo_0
+  store i1 true, ptr @"github.com/goplus/llgo/cl/_testrt/asm.init$guard", align 1
+  br label %_llgo_2
+
+_llgo_2:                                          ; preds = %_llgo_1, %_llgo_0
+  ret void
+}
+
+define void @"github.com/goplus/llgo/cl/_testrt/asm.main"() {
+_llgo_0:
+  call void asm sideeffect "nop", ""()
+  ret void
+}