cgo: full supports cgo preambles and auto compile c files

cl/instr.go

@@ -121,6 +121,20 @@ func (p *context) cgoCheckPointer(b llssa.Builder, args []ssa.Value) {
 	// don't need to do anything
 }
 
+// func _cgo_runtime_cgocall(fn unsafe.Pointer, arg unsafe.Pointer) int
+func (p *context) cgoCgocall(b llssa.Builder, args []ssa.Value) (ret llssa.Expr) {
+	pfn := p.compileValue(b, args[0])
+	pfn.Type = p.prog.Pointer(p.fn.Type)
+	fn := b.Load(pfn)
+	p.cgoRet = b.Call(fn, p.cgoArgs...)
+	return p.cgoRet
+}
+
+// func _Cgo_use(v any)
+func (p *context) cgoUse(b llssa.Builder, args []ssa.Value) {
+	// don't need to do anything
+}
+
 // -----------------------------------------------------------------------------
 
 // func index(arr *T, idx int) T
@@ -302,13 +316,15 @@ var llgoInstrs = map[string]int{
 	"atomicUMax": int(llgoAtomicUMax),
 	"atomicUMin": int(llgoAtomicUMin),
 
-	"_Cfunc_CString":   llgoCgoCString,
-	"_Cfunc_CBytes":    llgoCgoCBytes,
-	"_Cfunc_GoString":  llgoCgoGoString,
-	"_Cfunc_GoStringN": llgoCgoGoStringN,
-	"_Cfunc_GoBytes":   llgoCgoGoBytes,
-	"_Cfunc__CMalloc":  llgoCgoCMalloc,
-	"_cgoCheckPointer": llgoCgoCheckPointer,
+	"_Cfunc_CString":       llgoCgoCString,
+	"_Cfunc_CBytes":        llgoCgoCBytes,
+	"_Cfunc_GoString":      llgoCgoGoString,
+	"_Cfunc_GoStringN":     llgoCgoGoStringN,
+	"_Cfunc_GoBytes":       llgoCgoGoBytes,
+	"_Cfunc__CMalloc":      llgoCgoCMalloc,
+	"_cgoCheckPointer":     llgoCgoCheckPointer,
+	"_cgo_runtime_cgocall": llgoCgoCgocall,
+	"_Cgo_use":             llgoCgoUse,
 }
 
 // funcOf returns a function by name and set ftype = goFunc, cFunc, etc.
@@ -450,6 +466,10 @@ func (p *context) call(b llssa.Builder, act llssa.DoAction, call *ssa.CallCommon
 			ret = p.cgoCMalloc(b, args)
 		case llgoCgoCheckPointer:
 			p.cgoCheckPointer(b, args)
+		case llgoCgoCgocall:
+			p.cgoCgocall(b, args)
+		case llgoCgoUse:
+			p.cgoUse(b, args)
 		case llgoAdvance:
 			ret = p.advance(b, args)
 		case llgoIndex: