// Sets multiLine to true if the function body spans multiple lines.
func (p *printer) funcBody(b *ast.BlockStmt, headerSize int, isLit bool, multiLine *bool) {
	if b == nil {
		return
	}

	p.nesting++
	defer func() {
		p.nesting--
	}()

	if p.isOneLineFunc(b, headerSize) {
		sep := vtab
		if isLit {
			sep = blank
		}
		p.print(sep, b.Pos(), token.LBRACE)
		if len(b.List) > 0 {
			p.print(blank)
			for i, s := range b.List {
				if i > 0 {
					p.print(token.SEMICOLON, blank)
				}
				p.stmt(s, i == len(b.List)-1, ignoreMultiLine)
			}
			p.print(blank)
		}
		p.print(b.Rbrace, token.RBRACE)
		return
	}

	p.print(blank)
	p.block(b, 1)
	*multiLine = true
}

func rewriteFnWithRecovers(body *ast.BlockStmt, fnType *ast.FuncType) (wrapped *ast.FuncLit) {
	// The formatting of the channel declaration is ugly, but it's presented this way here to show how it will look in the actual output.
	// As far as I know, I would need to set the token.Pos values for the left and right braces of the struct and interface type literals
	// in order to get them on one line, but I don't think I can do that without computing all of the other token.Pos values for everything
	// else I generate.
	// TODO: These identifiers will probably conflict if there is a nested function that also has unnamed outputs. Should probably make a better gensym.
	outputDecls, outputs := inputsOrOutputs(fnType.Results, idents.result)
	if len(outputs) > 0 {
		body.List = astPrintf(`%s = func() (%s) {%s}()`, outputs, fnType.Results, body.List)
	}
	body.List = astPrintf(`
		{{%s}}
		_r := make(chan chan interface {
		})
		recovers, panicChan := godebug.EnterFuncWithRecovers(_r, func(ctx *godebug.Context) {
			%s
		})
		for recoverChan := range recovers {
			recoverChan <- recover()
		}
		if panicVal, ok := <-panicChan; ok {
			panic(panicVal)
		}
		{{return %s}}`, outputDecls, body.List, outputs)
	body.Rbrace = token.NoPos // without this I was getting extra whitespace at the end of the function
	return wrapped
}

// labels checks correct label use in body.
func (check *Checker) labels(body *ast.BlockStmt) {
	// set of all labels in this body
	all := NewScope(nil, body.Pos(), body.End(), "label")

	fwdJumps := check.blockBranches(all, nil, nil, body.List)

	// If there are any forward jumps left, no label was found for
	// the corresponding goto statements. Either those labels were
	// never defined, or they are inside blocks and not reachable
	// for the respective gotos.
	for _, jmp := range fwdJumps {
		var msg string
		name := jmp.Label.Name
		if alt := all.Lookup(name); alt != nil {
			msg = "goto %s jumps into block"
			alt.(*Label).used = true // avoid another error
		} else {
			msg = "label %s not declared"
		}
		check.errorf(jmp.Label.Pos(), msg, name)
	}

	// spec: "It is illegal to define a label that is never used."
	for _, obj := range all.elems {
		if lbl := obj.(*Label); !lbl.used {
			check.softErrorf(lbl.pos, "label %s declared but not used", lbl.name)
		}
	}
}

func (p *parser) parseBlock(n *parse.Node, scope *ast.Scope) *ast.BlockStmt {
	block := ast.BlockStmt{
		Lbrace: token.Pos(n.Child(0).Pos()),
		Rbrace: token.Pos(n.LastChild().Pos()),
	}
	eachListItem(stmt, n.Child(1), func(item *parse.Node) {
		block.List = append(block.List, p.parseStmt(item))
	})
	return &block
}

func (c *compiler) createBlockMetadata(stmt *ast.BlockStmt) llvm.DebugDescriptor {
	uniqueId++
	file := c.fileset.File(stmt.Pos())
	fd := llvm.FileDescriptor(file.Name())
	return &llvm.BlockDescriptor{
		File:    &fd,
		Line:    uint32(file.Line(stmt.Pos())),
		Context: c.currentDebugContext(),
		Id:      uniqueId,
	}
}

// block prints an *ast.BlockStmt; it always spans at least two lines.
func (p *printer) block(s *ast.BlockStmt, indent int, moveComments bool) {
	if moveComments {
		p.print(p.beforeComment(s.Pos()))
	} else {
		p.print(s.Pos())
	}
	p.print(token.LBRACE)
	p.stmtList(s.List, indent)
	p.linebreak(s.Rbrace.Line, 1, maxStmtNewlines, ignore, true)
	p.print(s.Rbrace, token.RBRACE)
}

// lastComment returns the last comment inside the provided block.
func lastComment(b *ast.BlockStmt, c []*ast.CommentGroup) (i int, last *ast.CommentGroup) {
	pos, end := b.Pos(), b.End()
	for j, cg := range c {
		if cg.Pos() < pos {
			continue
		}
		if cg.End() > end {
			break
		}
		i, last = j, cg
	}
	return
}

func (v *visitor) finalizeLoop(pos token.Pos, body *ast.BlockStmt) {
	if body == nil {
		return
	}
	line := pos2line(pos)
	if len(v.newIdents) == 0 {
		call := newCall(idents.godebug, "Line", ast.NewIdent(idents.ctx), ast.NewIdent(v.scopeVar), newInt(line))
		body.List = append(body.List, &ast.ExprStmt{X: call})
	} else {
		body.List = append([]ast.Stmt{
			astPrintf(`godebug.Line(ctx, scope, %s)`, strconv.Itoa(line))[0],
			newDeclareCall(idents.scope, v.newIdents),
		}, body.List...)
	}
}

func (lp *linePrinter) trimBlock(stmt *ast.BlockStmt) *ast.BlockStmt {
	if !lp.trim(stmt) {
		return lp.emptyBlock(stmt)
	}
	stmt.Rbrace = stmt.Lbrace
	return stmt
}

// New returns a new control-flow graph for the specified function body,
// which must be non-nil.
//
// The CFG builder calls mayReturn to determine whether a given function
// call may return.  For example, calls to panic, os.Exit, and log.Fatal
// do not return, so the builder can remove infeasible graph edges
// following such calls.  The builder calls mayReturn only for a
// CallExpr beneath an ExprStmt.
func New(body *ast.BlockStmt, mayReturn func(*ast.CallExpr) bool) *CFG {
	b := builder{
		mayReturn: mayReturn,
		cfg:       new(CFG),
	}
	b.current = b.newBlock("entry")
	b.stmt(body)

	// Does control fall off the end of the function's body?
	// Make implicit return explicit.
	if b.current != nil && !b.current.unreachable {
		b.add(&ast.ReturnStmt{
			Return: body.End() - 1,
		})
	}

	return b.cfg
}

func (check *Checker) funcBody(decl *declInfo, name string, sig *Signature, body *ast.BlockStmt) {
	if trace {
		if name == "" {
			name = "<function literal>"
		}
		fmt.Printf("--- %s: %s {\n", name, sig)
		defer fmt.Println("--- <end>")
	}

	// set function scope extent
	sig.scope.pos = body.Pos()
	sig.scope.end = body.End()

	// save/restore current context and setup function context
	// (and use 0 indentation at function start)
	defer func(ctxt context, indent int) {
		check.context = ctxt
		check.indent = indent
	}(check.context, check.indent)
	check.context = context{
		decl:  decl,
		scope: sig.scope,
		sig:   sig,
	}
	check.indent = 0

	check.stmtList(0, body.List)

	if check.hasLabel {
		check.labels(body)
	}

	if sig.results.Len() > 0 && !check.isTerminating(body, "") {
		check.error(body.Rbrace, "missing return")
	}

	// spec: "Implementation restriction: A compiler may make it illegal to
	// declare a variable inside a function body if the variable is never used."
	// (One could check each scope after use, but that distributes this check
	// over several places because CloseScope is not always called explicitly.)
	check.usage(sig.scope)
}

// filterBlocks keeps the statements that are need to calculate MappedCells.
func filterBlock(blk *ast.BlockStmt, filterIDs map[string]bool,
	imports map[string]string) (*ast.BlockStmt, []dictKey) {

	dicts := dictionaries(blk, imports)

	usedDks := make(map[dictKey]bool)
	filtered := make([]ast.Stmt, 0, len(blk.List))
	for i := len(blk.List) - 1; i >= 0; i-- {
		switch s := blk.List[i].(type) {
		// TODO(soheil): Support switches.
		case *ast.SwitchStmt:
		// TODO(soheil): Add support for ifs.
		case *ast.IfStmt:
		default:
			// TODO(soheil): It's actually more complicated that. What about
			// functional calls, what about multiple return values, ...?
			dks, yes := accessesDict(s, dicts)
			if yes {
				for _, dk := range dks {
					filterIDs[dk.k] = true
					usedDks[dk] = true
				}
				continue
			}

			dirty := false
			rIDs, wIDs := ids(s)
			for _, id := range wIDs {
				if filterIDs[id] {
					dirty = true
					break
				}
			}

			if !dirty {
				continue
			}

			for _, id := range rIDs {
				filterIDs[id] = true
			}

			filtered = append([]ast.Stmt{s}, filtered...)
		}
	}

	blk.List = filtered

	keys := make([]dictKey, 0, len(usedDks))
	for dk, _ := range usedDks {
		keys = append(keys, dk)
	}
	return blk, keys
}

// bodySize is like nodeSize but it is specialized for *ast.BlockStmt's.
func (p *printer) bodySize(b *ast.BlockStmt, maxSize int) int {
	pos1 := b.Pos()
	pos2 := b.Rbrace
	if pos1.IsValid() && pos2.IsValid() && p.lineFor(pos1) != p.lineFor(pos2) {
		// opening and closing brace are on different lines - don't make it a one-liner
		return maxSize + 1
	}
	if len(b.List) > 5 || p.commentBefore(p.posFor(pos2)) {
		// too many statements or there is a comment inside - don't make it a one-liner
		return maxSize + 1
	}
	// otherwise, estimate body size
	bodySize := 0
	for i, s := range b.List {
		if i > 0 {
			bodySize += 2 // space for a semicolon and blank
		}
		bodySize += p.nodeSize(s, maxSize)
	}
	return bodySize
}

/*
 * Given a test func named TestDoesSomethingNeat, rewrites it as
 * It("does something neat", func() { __test_body_here__ }) and adds it
 * to the Describe's list of statements
 */
func rewriteTestFuncAsItStatement(testFunc *ast.FuncDecl, rootNode *ast.File, describe *ast.CallExpr) {
	var funcIndex int = -1
	for index, child := range rootNode.Decls {
		if child == testFunc {
			funcIndex = index
			break
		}
	}

	if funcIndex < 0 {
		panic(fmt.Sprintf("Assert failed: Error finding index for test node %s\n", testFunc.Name.Name))
	}

	var block *ast.BlockStmt = blockStatementFromDescribe(describe)
	block.List = append(block.List, createItStatementForTestFunc(testFunc))
	replaceTestingTsWithGinkgoT(block, namedTestingTArg(testFunc))

	// remove the old test func from the root node's declarations
	rootNode.Decls = append(rootNode.Decls[:funcIndex], rootNode.Decls[funcIndex+1:]...)
	return
}

func (p *printer) isOneLineFunc(b *ast.BlockStmt, headerSize int) bool {
	pos1 := b.Pos()
	pos2 := b.Rbrace
	if pos1.IsValid() && pos2.IsValid() && pos1.Line != pos2.Line {
		// opening and closing brace are on different lines - don't make it a one-liner
		return false
	}
	if len(b.List) > 5 || p.commentBefore(pos2) {
		// too many statements or there is a comment inside - don't make it a one-liner
		return false
	}
	// otherwise, estimate body size
	const maxSize = 100
	bodySize := 0
	for i, s := range b.List {
		if i > 0 {
			bodySize += 2 // space for a semicolon and blank
		}
		bodySize += p.nodeSize(s, maxSize)
	}
	return headerSize+bodySize <= maxSize
}

func (c *compiler) VisitBlockStmt(stmt *ast.BlockStmt, createNewBlock bool) {
	c.pushDebugContext(c.createBlockMetadata(stmt))
	defer c.popDebugContext()
	c.setDebugLine(stmt.Pos())

	// This is a little awkward, but it makes dealing with branching easier.
	// A free-standing block statement (i.e. one not attached to a control
	// statement) will splice in a new block.
	var doneBlock llvm.BasicBlock
	if createNewBlock {
		currBlock := c.builder.GetInsertBlock()
		doneBlock = llvm.InsertBasicBlock(currBlock, "")
		doneBlock.MoveAfter(currBlock)
		newBlock := llvm.InsertBasicBlock(doneBlock, "")
		c.builder.CreateBr(newBlock)
		c.builder.SetInsertPointAtEnd(newBlock)
	}

	// Visit each statement in the block. When we have a terminator,
	// ignore everything until we get to a labeled statement.
	for _, stmt := range stmt.List {
		currBlock := c.builder.GetInsertBlock()
		in := currBlock.LastInstruction()
		if in.IsNil() || in.IsATerminatorInst().IsNil() {
			c.VisitStmt(stmt)
		} else if _, ok := stmt.(*ast.LabeledStmt); ok {
			// FIXME we might end up with a labeled statement
			// with no predecessors, due to dead code elimination.
			c.VisitStmt(stmt)
		}
	}

	if createNewBlock {
		c.maybeImplicitBranch(doneBlock)
		c.builder.SetInsertPointAtEnd(doneBlock)
	}
}

// Sets multiLine to true if the function body spans multiple lines.
func (p *printer) funcBody(b *ast.BlockStmt, isLit bool, multiLine *bool) {
	if b == nil {
		return
	}

	if (oneLineFuncDecls || isLit) && p.isOneLiner(b) {
		sep := vtab
		if isLit {
			sep = blank
		}
		if len(b.List) > 0 {
			p.print(sep, b.Pos(), token.LBRACE, blank)
			p.stmt(b.List[0], ignoreMultiLine)
			p.print(blank, b.Rbrace, token.RBRACE)
		} else {
			p.print(sep, b.Pos(), token.LBRACE, b.Rbrace, token.RBRACE)
		}
		return
	}

	p.print(blank)
	p.block(b, 1)
	*multiLine = true
}

func rewriteStructLiteralAsIdentifierAtTopOfBlock(newFile *ast.File, literalToReplace *ast.CompositeLit, name string) {
	var (
		foundStmtNode           ast.Stmt
		blocksSeen              []*ast.BlockStmt
		stmtsSeen               []ast.Stmt
		deleteOriginalStatement bool
		newAssignStmtToken      = token.DEFINE
	)

	ast.Inspect(newFile, func(node ast.Node) bool {
		switch node := node.(type) {
		case *ast.BlockStmt:
			if foundStmtNode == nil {
				blocksSeen = append(blocksSeen, node)
			}

		case ast.Stmt:
			stmtsSeen = append(stmtsSeen, node)
		}
		return true
	})

	var block *ast.BlockStmt
	var insertionIndex int

	for i := len(blocksSeen) - 1; i >= 0; i-- {
		b := blocksSeen[i]
		for j, stmt := range b.List {
			ast.Inspect(stmt, func(parentNode ast.Node) bool {
				switch parentNode := parentNode.(type) {
				case *ast.CompositeLit:
					if parentNode == literalToReplace {
						block = b
						insertionIndex = j
						return false
					}
				}
				return true
			})
		}
	}

	for i := len(stmtsSeen) - 1; i >= 0; i-- {
		s := stmtsSeen[i]
		ast.Inspect(s, func(node ast.Node) bool {
			switch node := node.(type) {
			case *ast.CompositeLit:
				if node == literalToReplace {
					foundStmtNode = s
					return false
				}
			}
			return true
		})
	}

	switch foundStmtNode := foundStmtNode.(type) {
	case *ast.AssignStmt:
		expr := foundStmtNode.Rhs[0]
		if expr == literalToReplace {
			deleteOriginalStatement = true

			switch ident := foundStmtNode.Lhs[0].(type) {
			case *ast.Ident:
				name = ident.Name
			}

			if foundStmtNode.Tok == token.ASSIGN {
				newAssignStmtToken = token.ASSIGN
			}
		}
	}

	lhsExpr := []ast.Expr{ast.NewIdent(name)}
	rhsExpr := []ast.Expr{&ast.CompositeLit{Type: literalToReplace.Type}}

	block.List = insert(block.List, insertionIndex, ast.AssignStmt{
		Lhs: lhsExpr,
		Rhs: rhsExpr,
		Tok: newAssignStmtToken,
	})
	insertionIndex++

	for _, elt := range literalToReplace.Elts {
		keyVal := elt.(*ast.KeyValueExpr)
		fieldName := keyVal.Key.(*ast.Ident)

		selector := &ast.SelectorExpr{
			X:   ast.NewIdent(name),
			Sel: ast.NewIdent(fieldName.Name),
		}
		innerLhs := []ast.Expr{selector}
		innerRhs := []ast.Expr{keyVal.Value}

		block.List = insert(block.List, insertionIndex, ast.AssignStmt{
			Lhs: innerLhs,
			Rhs: innerRhs,
			Tok: token.ASSIGN,
		})

//.........这里部分代码省略.........

// playExample synthesizes a new *ast.File based on the provided
// file with the provided function body as the body of main.
func playExample(file *ast.File, body *ast.BlockStmt) *ast.File {
	if !strings.HasSuffix(file.Name.Name, "_test") {
		// We don't support examples that are part of the
		// greater package (yet).
		return nil
	}

	// Find top-level declarations in the file.
	topDecls := make(map[*ast.Object]bool)
	for _, decl := range file.Decls {
		switch d := decl.(type) {
		case *ast.FuncDecl:
			topDecls[d.Name.Obj] = true
		case *ast.GenDecl:
			for _, spec := range d.Specs {
				switch s := spec.(type) {
				case *ast.TypeSpec:
					topDecls[s.Name.Obj] = true
				case *ast.ValueSpec:
					for _, id := range s.Names {
						topDecls[id.Obj] = true
					}
				}
			}
		}
	}

	// Find unresolved identifiers and uses of top-level declarations.
	unresolved := make(map[string]bool)
	usesTopDecl := false
	var inspectFunc func(ast.Node) bool
	inspectFunc = func(n ast.Node) bool {
		// For selector expressions, only inspect the left hand side.
		// (For an expression like fmt.Println, only add "fmt" to the
		// set of unresolved names, not "Println".)
		if e, ok := n.(*ast.SelectorExpr); ok {
			ast.Inspect(e.X, inspectFunc)
			return false
		}
		// For key value expressions, only inspect the value
		// as the key should be resolved by the type of the
		// composite literal.
		if e, ok := n.(*ast.KeyValueExpr); ok {
			ast.Inspect(e.Value, inspectFunc)
			return false
		}
		if id, ok := n.(*ast.Ident); ok {
			if id.Obj == nil {
				unresolved[id.Name] = true
			} else if topDecls[id.Obj] {
				usesTopDecl = true
			}
		}
		return true
	}
	ast.Inspect(body, inspectFunc)
	if usesTopDecl {
		// We don't support examples that are not self-contained (yet).
		return nil
	}

	// Remove predeclared identifiers from unresolved list.
	for n := range unresolved {
		if predeclaredTypes[n] || predeclaredConstants[n] || predeclaredFuncs[n] {
			delete(unresolved, n)
		}
	}

	// Use unresolved identifiers to determine the imports used by this
	// example. The heuristic assumes package names match base import
	// paths for imports w/o renames (should be good enough most of the time).
	namedImports := make(map[string]string) // [name]path
	var blankImports []ast.Spec             // _ imports
	for _, s := range file.Imports {
		p, err := strconv.Unquote(s.Path.Value)
		if err != nil {
			continue
		}
		n := path.Base(p)
		if s.Name != nil {
			n = s.Name.Name
			switch n {
			case "_":
				blankImports = append(blankImports, s)
				continue
			case ".":
				// We can't resolve dot imports (yet).
				return nil
			}
		}
		if unresolved[n] {
			namedImports[n] = p
			delete(unresolved, n)
		}
	}

	// If there are other unresolved identifiers, give up because this
	// synthesized file is not going to build.
//.........这里部分代码省略.........

// buildFunction takes a function Value, a list of parameters, and a body,
// and generates code for the function.
func (c *compiler) buildFunction(f *LLVMValue, context, params, results *types.Tuple, body *ast.BlockStmt) {
	if currblock := c.builder.GetInsertBlock(); !currblock.IsNil() {
		defer c.builder.SetInsertPointAtEnd(currblock)
	}
	llvm_fn := llvm.ConstExtractValue(f.LLVMValue(), []uint32{0})
	entry := llvm.AddBasicBlock(llvm_fn, "entry")
	c.builder.SetInsertPointAtEnd(entry)

	// For closures, context is the captured context values.
	var paramoffset int
	if context != nil {
		paramoffset++

		// Store the existing values. We're going to temporarily
		// replace the values with offsets into the context param.
		oldvalues := make([]*LLVMValue, context.Len())
		for i := range oldvalues {
			v := context.At(i)
			oldvalues[i] = c.objectdata[v].Value
		}
		defer func() {
			for i := range oldvalues {
				v := context.At(i)
				c.objectdata[v].Value = oldvalues[i]
			}
		}()

		// The context parameter is a pointer to a struct
		// whose elements are pointers to captured values.
		arg0 := llvm_fn.Param(0)
		for i := range oldvalues {
			v := context.At(i)
			argptr := c.builder.CreateStructGEP(arg0, i, "")
			argptr = c.builder.CreateLoad(argptr, "")
			ptrtyp := oldvalues[i].pointer.Type()
			newvalue := c.NewValue(argptr, ptrtyp)
			c.objectdata[v].Value = newvalue.makePointee()
		}
	}

	// Bind receiver, arguments and return values to their
	// identifiers/objects. We'll store each parameter on the stack so
	// they're addressable.
	nparams := int(params.Len())
	for i := 0; i < nparams; i++ {
		v := params.At(i)
		name := v.Name()
		if !isBlank(name) {
			value := llvm_fn.Param(i + paramoffset)
			c.newArgStackVar(i+1, f, v, value, name)
		}
	}

	funcstate := &function{LLVMValue: f, results: results}
	c.functions.push(funcstate)
	hasdefer := hasDefer(funcstate, body)

	// Allocate space on the stack for named results.
	for i := 0; i < results.Len(); i++ {
		v := results.At(i)
		name := v.Name()
		allocstack := !isBlank(name)
		if !allocstack && hasdefer {
			c.objectdata[v] = &ObjectData{}
			allocstack = true
		}
		if allocstack {
			typ := v.Type()
			llvmtyp := c.types.ToLLVM(typ)
			c.newStackVar(f, v, llvm.ConstNull(llvmtyp), name)
		}
	}

	// Create the function body.
	if hasdefer {
		c.makeDeferBlock(funcstate, body)
	}
	c.VisitBlockStmt(body, false)
	c.functions.pop()

	c.setDebugLine(body.End())

	// If the last instruction in the function is not a terminator, then
	// we either have unreachable code or a missing optional return statement
	// (the latter case is allowable only for functions without results).
	//
	// Use GetInsertBlock rather than LastBasicBlock, since the
	// last basic block might actually be a "defer" block.
	last := c.builder.GetInsertBlock()
	if in := last.LastInstruction(); in.IsNil() || in.IsATerminatorInst().IsNil() {
		c.builder.SetInsertPointAtEnd(last)
		if results.Len() == 0 {
			if funcstate.deferblock.IsNil() {
				c.builder.CreateRetVoid()
			} else {
				c.builder.CreateBr(funcstate.deferblock)
			}
		} else {
//.........这里部分代码省略.........