ruleguard/quasigo: pass args via ValueStack (#377)

It makes it easier to implement quasigo funcs call
later on, so Go->quasigo and quasigo->quasigo can use
the same calling convention.

Note that args can be bound once (until env.Stack.Reset),
which is useful in plugins-like context when you pass
the same argument list to all user functions.

Author: quasilyte

ruleguard/filters.go

@@ -186,7 +186,7 @@ func makeCustomVarFilter(src, varname string, fn *quasigo.Func) filterFunc {
 		// We should probably catch the panic here, print trace and return "false"
 		// from the filter (or even propagate that panic to let it crash).
 		params.varname = varname
-		result := quasigo.Call(params.env, fn, params)
+		result := quasigo.Call(params.env, fn)
 		if result.Value().(bool) {
 			return filterSuccess
 		}

ruleguard/quasigo/compile.go

@@ -54,7 +54,9 @@ type compiler struct {
 	locals           map[string]int
 	constantsPool    map[interface{}]int
 	intConstantsPool map[int]int
-	params           map[string]int
+
+	params    map[string]int
+	intParams map[string]int
 
 	code         []byte
 	constants    []interface{}
@@ -89,20 +91,31 @@ func (cl *compiler) compileFunc(fn *ast.FuncDecl) *Func {
 		panic(cl.errorUnsupportedType(fn.Name, cl.retType, "function result"))
 	}
 
-	dbg := funcDebugInfo{
-		paramNames: make([]string, cl.fnType.Params().Len()),
-	}
-
 	cl.params = make(map[string]int, cl.fnType.Params().Len())
+	cl.intParams = make(map[string]int, cl.fnType.Params().Len())
 	for i := 0; i < cl.fnType.Params().Len(); i++ {
 		p := cl.fnType.Params().At(i)
 		paramName := p.Name()
 		paramType := p.Type()
-		cl.params[paramName] = i
-		dbg.paramNames[i] = paramName
 		if !cl.isSupportedType(paramType) {
 			panic(cl.errorUnsupportedType(fn.Name, paramType, paramName+" param"))
 		}
+		if typeIsInt(paramType) {
+			cl.intParams[paramName] = len(cl.intParams)
+		} else {
+			cl.params[paramName] = len(cl.params)
+		}
+	}
+
+	dbg := funcDebugInfo{
+		paramNames:    make([]string, len(cl.params)),
+		intParamNames: make([]string, len(cl.intParams)),
+	}
+	for paramName, i := range cl.params {
+		dbg.paramNames[i] = paramName
+	}
+	for paramName, i := range cl.intParams {
+		dbg.intParamNames[i] = paramName
 	}
 
 	cl.compileStmt(fn.Body)
@@ -298,10 +311,20 @@ func (cl *compiler) compileAssignStmt(assign *ast.AssignStmt) {
 	}
 }
 
+func (cl *compiler) isParamName(varname string) bool {
+	if _, ok := cl.params[varname]; ok {
+		return true
+	}
+	if _, ok := cl.intParams[varname]; ok {
+		return true
+	}
+	return false
+}
+
 func (cl *compiler) getLocal(v ast.Expr, varname string) int {
 	id, ok := cl.locals[varname]
 	if !ok {
-		if _, ok := cl.params[varname]; ok {
+		if cl.isParamName(varname) {
 			panic(cl.errorf(v, "can't assign to %s, params are readonly", varname))
 		}
 		panic(cl.errorf(v, "%s is not a writeable local variable", varname))
@@ -645,7 +668,11 @@ func (cl *compiler) compileIdent(ident *ast.Ident) {
 		return
 	}
 	if paramIndex, ok := cl.params[ident.String()]; ok {
-		cl.emit8(pickOp(typeIsInt(tv.Type), opPushIntParam, opPushParam), paramIndex)
+		cl.emit8(opPushParam, paramIndex)
+		return
+	}
+	if paramIndex, ok := cl.intParams[ident.String()]; ok {
+		cl.emit8(opPushIntParam, paramIndex)
 		return
 	}
 	if localIndex, ok := cl.locals[ident.String()]; ok {

ruleguard/quasigo/compile_test.go

@@ -25,7 +25,7 @@ func TestCompile(t *testing.T) {
 		},
 
 		`return b`: {
-			`  PushParam 2 # b`,
+			`  PushParam 1 # b`,
 			`  ReturnTop`,
 		},
 
@@ -55,7 +55,7 @@ func TestCompile(t *testing.T) {
 			`  EqInt`,
 			`  Dup`,
 			`  JumpFalse 8 # L0`,
-			`  PushParam 1 # s`,
+			`  PushParam 0 # s`,
 			`  PushConst 0 # value="foo"`,
 			`  EqString`,
 			`L0:`,
@@ -81,7 +81,7 @@ func TestCompile(t *testing.T) {
 		},
 
 		`if b { return 1 }; return 0`: {
-			`  PushParam 2 # b`,
+			`  PushParam 1 # b`,
 			`  JumpFalse 6 # L0`,
 			`  PushIntConst 0 # value=1`,
 			`  ReturnIntTop`,
@@ -91,7 +91,7 @@ func TestCompile(t *testing.T) {
 		},
 
 		`if b { return 1 } else { return 0 }`: {
-			`  PushParam 2 # b`,
+			`  PushParam 1 # b`,
 			`  JumpFalse 6 # L0`,
 			`  PushIntConst 0 # value=1`,
 			`  ReturnIntTop`,
@@ -103,7 +103,7 @@ func TestCompile(t *testing.T) {
 		`x := 0; if b { x = 5 } else { x = 50 }; return x`: {
 			`  PushIntConst 0 # value=0`,
 			`  SetIntLocal 0 # x`,
-			`  PushParam 2 # b`,
+			`  PushParam 1 # b`,
 			`  JumpFalse 10 # L0`,
 			`  PushIntConst 1 # value=5`,
 			`  SetIntLocal 0 # x`,
@@ -124,7 +124,7 @@ func TestCompile(t *testing.T) {
 			`  PushConst 0 # value="a"`,
 			`  ReturnTop`,
 			`L0:`,
-			`  PushParam 2 # b`,
+			`  PushParam 1 # b`,
 			`  JumpFalse 6 # L1`,
 			`  PushConst 1 # value="b"`,
 			`  ReturnTop`,
@@ -134,58 +134,58 @@ func TestCompile(t *testing.T) {
 		},
 
 		`return eface == nil`: {
-			`  PushParam 3 # eface`,
+			`  PushParam 2 # eface`,
 			`  IsNil`,
 			`  ReturnTop`,
 		},
 
 		`return nil == eface`: {
-			`  PushParam 3 # eface`,
+			`  PushParam 2 # eface`,
 			`  IsNil`,
 			`  ReturnTop`,
 		},
 
 		`return eface != nil`: {
-			`  PushParam 3 # eface`,
+			`  PushParam 2 # eface`,
 			`  IsNotNil`,
 			`  ReturnTop`,
 		},
 
 		`return nil != eface`: {
-			`  PushParam 3 # eface`,
+			`  PushParam 2 # eface`,
 			`  IsNotNil`,
 			`  ReturnTop`,
 		},
 
 		`return s[:]`: {
-			`  PushParam 1 # s`,
+			`  PushParam 0 # s`,
 			`  ReturnTop`,
 		},
 
 		`return s[1:]`: {
-			`  PushParam 1 # s`,
+			`  PushParam 0 # s`,
 			`  PushIntConst 0 # value=1`,
 			`  StringSliceFrom`,
 			`  ReturnTop`,
 		},
 
 		`return s[:1]`: {
-			`  PushParam 1 # s`,
+			`  PushParam 0 # s`,
 			`  PushIntConst 0 # value=1`,
 			`  StringSliceTo`,
 			`  ReturnTop`,
 		},
 
 		`return s[1:2]`: {
-			`  PushParam 1 # s`,
+			`  PushParam 0 # s`,
 			`  PushIntConst 0 # value=1`,
 			`  PushIntConst 1 # value=2`,
 			`  StringSlice`,
 			`  ReturnTop`,
 		},
 
 		`return len(s) >= 0`: {
-			`  PushParam 1 # s`,
+			`  PushParam 0 # s`,
 			`  StringLen`,
 			`  PushIntConst 0 # value=0`,
 			`  GtEqInt`,

ruleguard/quasigo/debug_info.go

@@ -5,8 +5,9 @@ type debugInfo struct {
 }
 
 type funcDebugInfo struct {
-	paramNames []string
-	localNames []string
+	paramNames    []string
+	intParamNames []string
+	localNames    []string
 }
 
 func newDebugInfo() *debugInfo {

ruleguard/quasigo/disasm.go

@@ -39,10 +39,14 @@ func disasm(env *Env, fn *Func) string {
 			id := decode16(code, pc+1)
 			arg = id
 			comment = env.nativeFuncs[id].name
-		case opPushParam, opPushIntParam:
+		case opPushParam:
 			index := int(code[pc+1])
 			arg = index
 			comment = dbg.paramNames[index]
+		case opPushIntParam:
+			index := int(code[pc+1])
+			arg = index
+			comment = dbg.intParamNames[index]
 		case opSetLocal, opSetIntLocal, opPushLocal, opPushIntLocal, opIncLocal, opDecLocal:
 			index := int(code[pc+1])
 			arg = index

ruleguard/quasigo/eval.go

@@ -38,22 +38,22 @@ func (s *ValueStack) dup() { s.objects = append(s.objects, s.objects[len(s.objec
 // Identical to s.Pop() without using the result.
 func (s *ValueStack) discard() { s.objects = s.objects[:len(s.objects)-1] }
 
-func eval(env *EvalEnv, fn *Func, args []interface{}) CallResult {
+func eval(env *EvalEnv, fn *Func, top, intTop int) CallResult {
 	pc := 0
 	code := fn.code
-	stack := env.stack
+	stack := &env.Stack
 	var locals [maxFuncLocals]interface{}
 	var intLocals [maxFuncLocals]int
 
 	for {
 		switch op := opcode(code[pc]); op {
 		case opPushParam:
-			index := code[pc+1]
-			stack.Push(args[index])
+			index := int(code[pc+1])
+			stack.Push(stack.objects[top+index])
 			pc += 2
 		case opPushIntParam:
-			index := code[pc+1]
-			stack.PushInt(args[index].(int))
+			index := int(code[pc+1])
+			stack.PushInt(stack.ints[intTop+index])
 			pc += 2
 
 		case opPushLocal: