Merge pull request #1711 from nspcc-dev/compiler/inline

Allow to inline internal wrappers in compiler

pkg/compiler/analysis.go

@@ -55,14 +55,14 @@ func (c *codegen) traverseGlobals() (int, int, int) {
 				switch n := node.(type) {
 				case *ast.FuncDecl:
 					if isInitFunc(n) {
-						c, _ := countLocals(n)
+						num, _ := c.countLocals(n)
-						if c > initLocals {
+						if num > initLocals {
-							initLocals = c
+							initLocals = num
 						}
 					} else if isDeployFunc(n) {
-						c, _ := countLocals(n)
+						num, _ := c.countLocals(n)
-						if c > deployLocals {
+						if num > deployLocals {
-							deployLocals = c
+							deployLocals = num
 						}
 					}
 					return !hasDefer
@@ -175,10 +175,16 @@ func (f funcUsage) funcUsed(name string) bool {
 }
 
 // lastStmtIsReturn checks if last statement of the declaration was return statement..
-func lastStmtIsReturn(decl *ast.FuncDecl) (b bool) {
+func lastStmtIsReturn(body *ast.BlockStmt) (b bool) {
-	if l := len(decl.Body.List); l != 0 {
+	if l := len(body.List); l != 0 {
-		_, ok := decl.Body.List[l-1].(*ast.ReturnStmt)
+		switch inner := body.List[l-1].(type) {
-		return ok
+		case *ast.BlockStmt:
+			return lastStmtIsReturn(inner)
+		case *ast.ReturnStmt:
+			return true
+		default:
+			return false
+		}
 	}
 	return false
 }
@@ -298,3 +304,11 @@ func canConvert(s string) bool {
 	}
 	return true
 }
+
+// canInline returns true if function is to be inlined.
+// Currently there is a static list of function which are inlined,
+// this may change in future.
+func canInline(s string) bool {
+	return isNativeHelpersPath(s) ||
+		strings.HasPrefix(s, "github.com/nspcc-dev/neo-go/pkg/compiler/testdata/inline")
+}

pkg/compiler/codegen.go

@@ -31,6 +31,8 @@ type codegen struct {
 
 	// Type information.
 	typeInfo *types.Info
+	// pkgInfoInline is stack of type information for packages containing inline functions.
+	pkgInfoInline []*loader.PackageInfo
 
 	// A mapping of func identifiers with their scope.
 	funcs map[string]*funcScope
@@ -192,20 +194,21 @@ func (c *codegen) emitStoreStructField(i int) {
 
 // getVarIndex returns variable type and position in corresponding slot,
 // according to current scope.
-func (c *codegen) getVarIndex(pkg string, name string) (varType, int) {
+func (c *codegen) getVarIndex(pkg string, name string) *varInfo {
 	if pkg == "" {
 		if c.scope != nil {
-			vt, val := c.scope.vars.getVarIndex(name)
+			vi := c.scope.vars.getVarInfo(name)
-			if val >= 0 {
+			if vi != nil {
-				return vt, val
+				return vi
 			}
 		}
 	}
 	if i, ok := c.globals[c.getIdentName(pkg, name)]; ok {
-		return varGlobal, i
+		return &varInfo{refType: varGlobal, index: i}
 	}
 
-	return varLocal, c.scope.newVariable(varLocal, name)
+	c.scope.newVariable(varLocal, name)
+	return c.scope.vars.getVarInfo(name)
 }
 
 func getBaseOpcode(t varType) (opcode.Opcode, opcode.Opcode) {
@@ -223,8 +226,15 @@ func getBaseOpcode(t varType) (opcode.Opcode, opcode.Opcode) {
 
 // emitLoadVar loads specified variable to the evaluation stack.
 func (c *codegen) emitLoadVar(pkg string, name string) {
-	t, i := c.getVarIndex(pkg, name)
+	vi := c.getVarIndex(pkg, name)
-	c.emitLoadByIndex(t, i)
+	if vi.tv.Value != nil {
+		c.emitLoadConst(vi.tv)
+		return
+	} else if vi.index == unspecifiedVarIndex {
+		emit.Opcodes(c.prog.BinWriter, opcode.PUSHNULL)
+		return
+	}
+	c.emitLoadByIndex(vi.refType, vi.index)
 }
 
 // emitLoadByIndex loads specified variable type with index i.
@@ -243,8 +253,8 @@ func (c *codegen) emitStoreVar(pkg string, name string) {
 		emit.Opcodes(c.prog.BinWriter, opcode.DROP)
 		return
 	}
-	t, i := c.getVarIndex(pkg, name)
+	vi := c.getVarIndex(pkg, name)
-	c.emitStoreByIndex(t, i)
+	c.emitStoreByIndex(vi.refType, vi.index)
 }
 
 // emitLoadByIndex stores top value in the specified variable type with index i.
@@ -320,7 +330,7 @@ func (c *codegen) convertInitFuncs(f *ast.File, pkg *types.Package, seenBefore b
 		case *ast.FuncDecl:
 			if isInitFunc(n) {
 				if seenBefore {
-					cnt, _ := countLocals(n)
+					cnt, _ := c.countLocals(n)
 					c.clearSlots(cnt)
 					seenBefore = true
 				}
@@ -352,7 +362,7 @@ func (c *codegen) convertDeployFuncs() {
 			case *ast.FuncDecl:
 				if isDeployFunc(n) {
 					if seenBefore {
-						cnt, _ := countLocals(n)
+						cnt, _ := c.countLocals(n)
 						c.clearSlots(cnt)
 					}
 					c.convertFuncDecl(f, n, pkg)
@@ -398,7 +408,7 @@ func (c *codegen) convertFuncDecl(file ast.Node, decl *ast.FuncDecl, pkg *types.
 	// All globals copied into the scope of the function need to be added
 	// to the stack size of the function.
 	if !isInit && !isDeploy {
-		sizeLoc := f.countLocals()
+		sizeLoc := c.countLocalsWithDefer(f)
 		if sizeLoc > 255 {
 			c.prog.Err = errors.New("maximum of 255 local variables is allowed")
 		}
@@ -440,7 +450,7 @@ func (c *codegen) convertFuncDecl(file ast.Node, decl *ast.FuncDecl, pkg *types.
 	// If we have reached the end of the function without encountering `return` statement,
 	// we should clean alt.stack manually.
 	// This can be the case with void and named-return functions.
-	if !isInit && !isDeploy && !lastStmtIsReturn(decl) {
+	if !isInit && !isDeploy && !lastStmtIsReturn(decl.Body) {
 		c.saveSequencePoint(decl.Body)
 		emit.Opcodes(c.prog.BinWriter, opcode.RET)
 	}
@@ -623,7 +633,9 @@ func (c *codegen) Visit(node ast.Node) ast.Visitor {
 		c.processDefers()
 
 		c.saveSequencePoint(n)
+		if len(c.pkgInfoInline) == 0 {
 			emit.Opcodes(c.prog.BinWriter, opcode.RET)
+		}
 		return nil
 
 	case *ast.IfStmt:
@@ -800,7 +812,12 @@ func (c *codegen) Visit(node ast.Node) ast.Visitor {
 
 		switch fun := n.Fun.(type) {
 		case *ast.Ident:
-			f, ok = c.funcs[c.getIdentName("", fun.Name)]
+			var pkgName string
+			if len(c.pkgInfoInline) != 0 {
+				pkgName = c.pkgInfoInline[len(c.pkgInfoInline)-1].Pkg.Path()
+			}
+			f, ok = c.funcs[c.getIdentName(pkgName, fun.Name)]
+
 			isBuiltin = isGoBuiltin(fun.Name)
 			if !ok && !isBuiltin {
 				name = fun.Name
@@ -809,6 +826,10 @@ func (c *codegen) Visit(node ast.Node) ast.Visitor {
 			if fun.Obj != nil && fun.Obj.Kind == ast.Var {
 				isFunc = true
 			}
+			if ok && canInline(f.pkg.Path()) {
+				c.inlineCall(f, n)
+				return nil
+			}
 		case *ast.SelectorExpr:
 			// If this is a method call we need to walk the AST to load the struct locally.
 			// Otherwise this is a function call from a imported package and we can call it
@@ -824,6 +845,10 @@ func (c *codegen) Visit(node ast.Node) ast.Visitor {
 			if ok {
 				f.selector = fun.X.(*ast.Ident)
 				isBuiltin = isCustomBuiltin(f)
+				if canInline(f.pkg.Path()) {
+					c.inlineCall(f, n)
+					return nil
+				}
 			} else {
 				typ := c.typeOf(fun)
 				if _, ok := typ.(*types.Signature); ok {
@@ -867,10 +892,7 @@ func (c *codegen) Visit(node ast.Node) ast.Visitor {
 			typ, ok := c.typeOf(n.Fun).(*types.Signature)
 			if ok && typ.Variadic() && !n.Ellipsis.IsValid() {
 				// pack variadic args into an array only if last argument is not of form `...`
-				varSize := len(n.Args) - typ.Params().Len() + 1
+				varSize := c.packVarArgs(n, typ)
-				c.emitReverse(varSize)
-				emit.Int(c.prog.BinWriter, int64(varSize))
-				emit.Opcodes(c.prog.BinWriter, opcode.PACK)
 				numArgs -= varSize - 1
 			}
 			c.emitReverse(numArgs)
@@ -1207,6 +1229,16 @@ func (c *codegen) Visit(node ast.Node) ast.Visitor {
 	return c
 }
 
+// packVarArgs packs variadic arguments into an array
+// and returns amount of arguments packed.
+func (c *codegen) packVarArgs(n *ast.CallExpr, typ *types.Signature) int {
+	varSize := len(n.Args) - typ.Params().Len() + 1
+	c.emitReverse(varSize)
+	emit.Int(c.prog.BinWriter, int64(varSize))
+	emit.Opcodes(c.prog.BinWriter, opcode.PACK)
+	return varSize
+}
+
 // processDefers emits code for `defer` statements.
 // TRY-related opcodes handle exception as follows:
 // 1. CATCH block is executed only if exception has occurred.
@@ -1919,7 +1951,7 @@ func (c *codegen) compile(info *buildInfo, pkg *loader.PackageInfo) error {
 				// of bytecode space.
 				name := c.getFuncNameFromDecl(pkg.Path(), n)
 				if !isInitFunc(n) && !isDeployFunc(n) && funUsage.funcUsed(name) &&
-					(!isInteropPath(pkg.Path()) || isNativeHelpersPath(pkg.Path())) {
+					(!isInteropPath(pkg.Path()) && !canInline(pkg.Path())) {
 					c.convertFuncDecl(f, n, pkg)
 				}
 			}
@@ -1970,7 +2002,8 @@ func (c *codegen) resolveFuncDecls(f *ast.File, pkg *types.Package) {
 	for _, decl := range f.Decls {
 		switch n := decl.(type) {
 		case *ast.FuncDecl:
-			c.newFunc(n)
+			fs := c.newFunc(n)
+			fs.file = f
 		}
 	}
 }

pkg/compiler/func_scope.go

@@ -22,6 +22,8 @@ type funcScope struct {
 	// Package where the function is defined.
 	pkg *types.Package
 
+	file *ast.File
+
 	// Program label of the scope
 	label uint16
 
@@ -100,11 +102,47 @@ func (c *funcScope) analyzeVoidCalls(node ast.Node) bool {
 	return true
 }
 
-func countLocals(decl *ast.FuncDecl) (int, bool) {
+func (c *codegen) countLocals(decl *ast.FuncDecl) (int, bool) {
+	return c.countLocalsInline(decl, nil, nil)
+}
+
+func (c *codegen) countLocalsInline(decl *ast.FuncDecl, pkg *types.Package, f *funcScope) (int, bool) {
+	oldMap := c.importMap
+	if pkg != nil {
+		c.fillImportMap(f.file, pkg)
+	}
+
 	size := 0
 	hasDefer := false
 	ast.Inspect(decl, func(n ast.Node) bool {
 		switch n := n.(type) {
+		case *ast.CallExpr:
+			var name string
+			switch fun := n.Fun.(type) {
+			case *ast.Ident:
+				var pkgName string
+				if pkg != nil {
+					pkgName = pkg.Path()
+				}
+				name = c.getIdentName(pkgName, fun.Name)
+			case *ast.SelectorExpr:
+				name, _ = c.getFuncNameFromSelector(fun)
+			default:
+				return false
+			}
+			if inner, ok := c.funcs[name]; ok && canInline(name) {
+				for i := range n.Args {
+					switch n.Args[i].(type) {
+					case *ast.Ident:
+					case *ast.BasicLit:
+					default:
+						size++
+					}
+				}
+				innerSz, _ := c.countLocalsInline(inner.decl, inner.pkg, inner)
+				size += innerSz
+			}
+			return false
 		case *ast.FuncType:
 			num := n.Results.NumFields()
 			if num != 0 && len(n.Results.List[0].Names) != 0 {
@@ -117,7 +155,11 @@ func countLocals(decl *ast.FuncDecl) (int, bool) {
 		case *ast.DeferStmt:
 			hasDefer = true
 			return false
-		case *ast.ReturnStmt, *ast.IfStmt:
+		case *ast.ReturnStmt:
+			if pkg == nil {
+				size++
+			}
+		case *ast.IfStmt:
 			size++
 		// This handles the inline GenDecl like "var x = 2"
 		case *ast.ValueSpec:
@@ -134,13 +176,16 @@ func countLocals(decl *ast.FuncDecl) (int, bool) {
 		}
 		return true
 	})
+	if pkg != nil {
+		c.importMap = oldMap
+	}
 	return size, hasDefer
 }
 
-func (c *funcScope) countLocals() int {
+func (c *codegen) countLocalsWithDefer(f *funcScope) int {
-	size, hasDefer := countLocals(c.decl)
+	size, hasDefer := c.countLocals(f.decl)
 	if hasDefer {
-		c.finallyProcessedIndex = size
+		f.finallyProcessedIndex = size
 		size++
 	}
 	return size
@@ -154,12 +199,6 @@ func (c *funcScope) countArgs() int {
 	return n
 }
 
-func (c *funcScope) stackSize() int64 {
-	size := c.countLocals()
-	numArgs := c.countArgs()
-	return int64(size + numArgs)
-}
-
 // newVariable creates a new local variable or argument in the scope of the function.
 func (c *funcScope) newVariable(t varType, name string) int {
 	return c.vars.newVariable(t, name)

pkg/compiler/inline.go

@@ -0,0 +1,94 @@
+package compiler
+
+import (
+	"go/ast"
+	"go/types"
+
+	"github.com/nspcc-dev/neo-go/pkg/vm/emit"
+	"github.com/nspcc-dev/neo-go/pkg/vm/opcode"
+)
+
+// inlineCall inlines call of n for function represented by f.
+// Call `f(a,b)` for definition `func f(x,y int)` is translated to block:
+// {
+//    x := a
+//    y := b
+//    <inline body of f directly>
+// }
+func (c *codegen) inlineCall(f *funcScope, n *ast.CallExpr) {
+	pkg := c.buildInfo.program.Package(f.pkg.Path())
+	sig := c.typeOf(n.Fun).(*types.Signature)
+
+	// Arguments need to be walked with the current scope,
+	// while stored in the new.
+	oldScope := c.scope.vars.locals
+	c.scope.vars.newScope()
+	newScope := c.scope.vars.locals
+	defer c.scope.vars.dropScope()
+
+	hasVarArgs := !n.Ellipsis.IsValid()
+	needPack := sig.Variadic() && hasVarArgs
+	for i := range n.Args {
+		c.scope.vars.locals = oldScope
+		// true if normal arg or var arg is `slice...`
+		needStore := i < sig.Params().Len()-1 || !sig.Variadic() || !hasVarArgs
+		if !needStore {
+			break
+		}
+		name := sig.Params().At(i).Name()
+		if tv := c.typeAndValueOf(n.Args[i]); tv.Value != nil {
+			c.scope.vars.locals = newScope
+			c.scope.vars.addAlias(name, varLocal, unspecifiedVarIndex, tv)
+			continue
+		}
+		if arg, ok := n.Args[i].(*ast.Ident); ok {
+			// When function argument is variable or const, we may avoid
+			// introducing additional variables for parameters.
+			// This is done by providing additional alias to variable.
+			if vi := c.scope.vars.getVarInfo(arg.Name); vi != nil {
+				c.scope.vars.locals = newScope
+				c.scope.vars.addAlias(name, vi.refType, vi.index, vi.tv)
+				continue
+			} else if arg.Name == "nil" {
+				c.scope.vars.locals = newScope
+				c.scope.vars.addAlias(name, varLocal, unspecifiedVarIndex, types.TypeAndValue{})
+				continue
+			} else if index, ok := c.globals[c.getIdentName("", arg.Name)]; ok {
+				c.scope.vars.locals = newScope
+				c.scope.vars.addAlias(name, varGlobal, index, types.TypeAndValue{})
+				continue
+			}
+		}
+		ast.Walk(c, n.Args[i])
+		c.scope.vars.locals = newScope
+		c.scope.newLocal(name)
+		c.emitStoreVar("", name)
+	}
+
+	if needPack {
+		// traverse variadic args and pack them
+		// if they are provided directly i.e. without `...`
+		c.scope.vars.locals = oldScope
+		for i := sig.Params().Len() - 1; i < len(n.Args); i++ {
+			ast.Walk(c, n.Args[i])
+		}
+		c.scope.vars.locals = newScope
+		c.packVarArgs(n, sig)
+		name := sig.Params().At(sig.Params().Len() - 1).Name()
+		c.scope.newLocal(name)
+		c.emitStoreVar("", name)
+	}
+
+	c.pkgInfoInline = append(c.pkgInfoInline, pkg)
+	oldMap := c.importMap
+	c.fillImportMap(f.file, pkg.Pkg)
+	ast.Inspect(f.decl, c.scope.analyzeVoidCalls)
+	ast.Walk(c, f.decl.Body)
+	if c.scope.voidCalls[n] {
+		for i := 0; i < f.decl.Type.Results.NumFields(); i++ {
+			emit.Opcodes(c.prog.BinWriter, opcode.DROP)
+		}
+	}
+	c.importMap = oldMap
+	c.pkgInfoInline = c.pkgInfoInline[:len(c.pkgInfoInline)-1]
+}

pkg/compiler/inline_test.go

@@ -0,0 +1,163 @@
+package compiler_test
+
+import (
+	"fmt"
+	"math/big"
+	"strings"
+	"testing"
+
+	"github.com/nspcc-dev/neo-go/pkg/compiler"
+	"github.com/nspcc-dev/neo-go/pkg/vm/opcode"
+	"github.com/stretchr/testify/require"
+)
+
+func checkCallCount(t *testing.T, src string, expectedCall, expectedInitSlot int) {
+	v := vmAndCompile(t, src)
+	ctx := v.Context()
+	actualCall := 0
+	actualInitSlot := 0
+
+	for op, _, err := ctx.Next(); ; op, _, err = ctx.Next() {
+		require.NoError(t, err)
+		switch op {
+		case opcode.CALL, opcode.CALLL:
+			actualCall++
+		case opcode.INITSLOT:
+			actualInitSlot++
+		}
+		if ctx.IP() == ctx.LenInstr() {
+			break
+		}
+	}
+	require.Equal(t, expectedCall, actualCall)
+	require.Equal(t, expectedInitSlot, actualInitSlot)
+}
+
+func TestInline(t *testing.T) {
+	srcTmpl := `package foo
+	import "github.com/nspcc-dev/neo-go/pkg/compiler/testdata/inline"
+	// local alias
+	func sum(a, b int) int {
+		return 42
+	}
+	var Num = 1
+	func Main() int {
+		%s
+	}`
+	t.Run("no return", func(t *testing.T) {
+		src := fmt.Sprintf(srcTmpl, `inline.NoArgsNoReturn()
+			return 1`)
+		checkCallCount(t, src, 0, 1)
+		eval(t, src, big.NewInt(1))
+	})
+	t.Run("has return, dropped", func(t *testing.T) {
+		src := fmt.Sprintf(srcTmpl, `inline.NoArgsReturn1()
+			return 2`)
+		checkCallCount(t, src, 0, 1)
+		eval(t, src, big.NewInt(2))
+	})
+	t.Run("drop twice", func(t *testing.T) {
+		src := fmt.Sprintf(srcTmpl, `inline.DropInsideInline()
+			return 42`)
+		checkCallCount(t, src, 0, 1)
+		eval(t, src, big.NewInt(42))
+	})
+	t.Run("no args return 1", func(t *testing.T) {
+		src := fmt.Sprintf(srcTmpl, `return inline.NoArgsReturn1()`)
+		checkCallCount(t, src, 0, 1)
+		eval(t, src, big.NewInt(1))
+	})
+	t.Run("sum", func(t *testing.T) {
+		src := fmt.Sprintf(srcTmpl, `return inline.Sum(1, 2)`)
+		checkCallCount(t, src, 0, 1)
+		eval(t, src, big.NewInt(3))
+	})
+	t.Run("sum squared (nested inline)", func(t *testing.T) {
+		src := fmt.Sprintf(srcTmpl, `return inline.SumSquared(1, 2)`)
+		checkCallCount(t, src, 0, 1)
+		eval(t, src, big.NewInt(9))
+	})
+	t.Run("inline function in inline function parameter", func(t *testing.T) {
+		src := fmt.Sprintf(srcTmpl, `return inline.Sum(inline.SumSquared(1, 2), inline.Sum(3, 4))`)
+		checkCallCount(t, src, 0, 1)
+		eval(t, src, big.NewInt(9+3+4))
+	})
+	t.Run("global name clash", func(t *testing.T) {
+		src := fmt.Sprintf(srcTmpl, `return inline.GetSumSameName()`)
+		checkCallCount(t, src, 0, 1)
+		eval(t, src, big.NewInt(42))
+	})
+	t.Run("local name clash", func(t *testing.T) {
+		src := fmt.Sprintf(srcTmpl, `return inline.Sum(inline.SumSquared(1, 2), sum(3, 4))`)
+		checkCallCount(t, src, 1, 2)
+		eval(t, src, big.NewInt(51))
+	})
+	t.Run("var args, empty", func(t *testing.T) {
+		src := fmt.Sprintf(srcTmpl, `return inline.VarSum(11)`)
+		checkCallCount(t, src, 0, 1)
+		eval(t, src, big.NewInt(11))
+	})
+	t.Run("var args, direct", func(t *testing.T) {
+		src := fmt.Sprintf(srcTmpl, `return inline.VarSum(11, 14, 17)`)
+		checkCallCount(t, src, 0, 1)
+		eval(t, src, big.NewInt(42))
+	})
+	t.Run("var args, array", func(t *testing.T) {
+		src := fmt.Sprintf(srcTmpl, `arr := []int{14, 17} 
+			return inline.VarSum(11, arr...)`)
+		checkCallCount(t, src, 0, 1)
+		eval(t, src, big.NewInt(42))
+	})
+	t.Run("globals", func(t *testing.T) {
+		src := fmt.Sprintf(srcTmpl, `return inline.Concat(Num)`)
+		checkCallCount(t, src, 0, 1)
+		eval(t, src, big.NewInt(221))
+	})
+}
+
+func TestInlineConversion(t *testing.T) {
+	src1 := `package foo
+	import "github.com/nspcc-dev/neo-go/pkg/compiler/testdata/inline"
+	var _ = inline.A
+	func Main() int {
+		a := 2
+		return inline.SumSquared(1, a)
+	}`
+	b1, err := compiler.Compile("foo.go", strings.NewReader(src1))
+	require.NoError(t, err)
+
+	src2 := `package foo
+	import "github.com/nspcc-dev/neo-go/pkg/compiler/testdata/inline"
+	var _ = inline.A
+	func Main() int {
+		a := 2
+		{
+			return (1 + a) * (1 + a)
+		}
+	}`
+	b2, err := compiler.Compile("foo.go", strings.NewReader(src2))
+	require.NoError(t, err)
+	require.Equal(t, b2, b1)
+}
+
+func TestInlineConversionQualified(t *testing.T) {
+	src1 := `package foo
+	import "github.com/nspcc-dev/neo-go/pkg/compiler/testdata/inline"
+	var A = 1
+	func Main() int {
+		return inline.Concat(A)
+	}`
+	b1, err := compiler.Compile("foo.go", strings.NewReader(src1))
+	require.NoError(t, err)
+
+	src2 := `package foo
+	import "github.com/nspcc-dev/neo-go/pkg/compiler/testdata/inline"
+	import "github.com/nspcc-dev/neo-go/pkg/compiler/testdata/inline/b"
+	var A = 1
+	func Main() int {
+		return A * 100 + b.A * 10 + inline.A
+	}`
+	b2, err := compiler.Compile("foo.go", strings.NewReader(src2))
+	require.NoError(t, err)
+	require.Equal(t, b2, b1)
+}

pkg/compiler/testdata/inline/a/a.go

@@ -0,0 +1,7 @@
+package a
+
+var A = 29
+
+func GetA() int {
+	return A
+}

pkg/compiler/testdata/inline/b/b.go

@@ -0,0 +1,7 @@
+package b
+
+var A = 12
+
+func GetA() int {
+	return A
+}

pkg/compiler/testdata/inline/inline.go

@@ -0,0 +1,44 @@
+package inline
+
+import (
+	"github.com/nspcc-dev/neo-go/pkg/compiler/testdata/inline/a"
+	"github.com/nspcc-dev/neo-go/pkg/compiler/testdata/inline/b"
+)
+
+func NoArgsNoReturn() {}
+func NoArgsReturn1() int {
+	return 1
+}
+func Sum(a, b int) int {
+	return a + b
+}
+func sum(x, y int) int {
+	return x + y
+}
+func SumSquared(a, b int) int {
+	return sum(a, b) * (a + b)
+}
+
+var A = 1
+
+func GetSumSameName() int {
+	return a.GetA() + b.GetA() + A
+}
+
+func DropInsideInline() int {
+	sum(1, 2)
+	sum(3, 4)
+	return 7
+}
+
+func VarSum(a int, b ...int) int {
+	sum := a
+	for i := range b {
+		sum += b[i]
+	}
+	return sum
+}
+
+func Concat(n int) int {
+	return n*100 + b.A*10 + A
+}

pkg/compiler/types.go

@@ -8,6 +8,11 @@ import (
 )
 
 func (c *codegen) typeAndValueOf(e ast.Expr) types.TypeAndValue {
+	for i := len(c.pkgInfoInline) - 1; i >= 0; i-- {
+		if tv, ok := c.pkgInfoInline[i].Types[e]; ok {
+			return tv
+		}
+	}
 	return c.typeInfo.Types[e]
 }
 

pkg/compiler/vars.go

@@ -1,12 +1,24 @@
 package compiler
 
+import (
+	"go/types"
+)
+
 type varScope struct {
 	localsCnt int
 	argCnt    int
 	arguments map[string]int
-	locals    []map[string]int
+	locals    []map[string]varInfo
 }
 
+type varInfo struct {
+	refType varType
+	index   int
+	tv      types.TypeAndValue
+}
+
+const unspecifiedVarIndex = -1
+
 func newVarScope() varScope {
 	return varScope{
 		arguments: make(map[string]int),
@@ -14,23 +26,34 @@ func newVarScope() varScope {
 }
 
 func (c *varScope) newScope() {
-	c.locals = append(c.locals, map[string]int{})
+	c.locals = append(c.locals, map[string]varInfo{})
 }
 
 func (c *varScope) dropScope() {
 	c.locals = c.locals[:len(c.locals)-1]
 }
 
-func (c *varScope) getVarIndex(name string) (varType, int) {
+func (c *varScope) addAlias(name string, vt varType, index int, tv types.TypeAndValue) {
+	c.locals[len(c.locals)-1][name] = varInfo{
+		refType: vt,
+		index:   index,
+		tv:      tv,
+	}
+}
+
+func (c *varScope) getVarInfo(name string) *varInfo {
 	for i := len(c.locals) - 1; i >= 0; i-- {
-		if i, ok := c.locals[i][name]; ok {
+		if vi, ok := c.locals[i][name]; ok {
-			return varLocal, i
+			return &vi
 		}
 	}
 	if i, ok := c.arguments[name]; ok {
-		return varArgument, i
+		return &varInfo{
+			refType: varArgument,
+			index:   i,
 		}
-	return 0, -1
+	}
+	return nil
 }
 
 // newVariable creates a new local variable or argument in the scope of the function.
@@ -56,7 +79,10 @@ func (c *varScope) newVariable(t varType, name string) int {
 func (c *varScope) newLocal(name string) int {
 	idx := len(c.locals) - 1
 	m := c.locals[idx]
-	m[name] = c.localsCnt
+	m[name] = varInfo{
+		refType: varLocal,
+		index:   c.localsCnt,
+	}
 	c.localsCnt++
 	c.locals[idx] = m
 	return c.localsCnt - 1