Golang loader.PackageInfo类代码示例

// processAnnotations takes an *ssa.Package and a
// *importer.PackageInfo, and processes all of the
// llgo source annotations attached to each top-level
// function and global variable.
func (c *compiler) processAnnotations(u *unit, pkginfo *loader.PackageInfo) {
	members := make(map[types.Object]*LLVMValue, len(u.globals))
	for k, v := range u.globals {
		members[k.(ssa.Member).Object()] = v
	}
	applyAttributes := func(attrs []Attribute, idents ...*ast.Ident) {
		if len(attrs) == 0 {
			return
		}
		for _, ident := range idents {
			if v := members[pkginfo.ObjectOf(ident)]; v != nil {
				for _, attr := range attrs {
					attr.Apply(v)
				}
			}
		}
	}
	for _, f := range pkginfo.Files {
		for _, decl := range f.Decls {
			switch decl := decl.(type) {
			case *ast.FuncDecl:
				attrs := parseAttributes(decl.Doc)
				applyAttributes(attrs, decl.Name)
			case *ast.GenDecl:
				if decl.Tok != token.VAR {
					continue
				}
				for _, spec := range decl.Specs {
					varspec := spec.(*ast.ValueSpec)
					attrs := parseAttributes(decl.Doc)
					applyAttributes(attrs, varspec.Names...)
				}
			}
		}
	}
}

// findInterestingNode classifies the syntax node denoted by path as one of:
//    - an expression, part of an expression or a reference to a constant
//      or variable;
//    - a type, part of a type, or a reference to a named type;
//    - a statement, part of a statement, or a label referring to a statement;
//    - part of a package declaration or import spec.
//    - none of the above.
// and returns the most "interesting" associated node, which may be
// the same node, an ancestor or a descendent.
//
func findInterestingNode(pkginfo *loader.PackageInfo, path []ast.Node) ([]ast.Node, action) {
	// TODO(adonovan): integrate with go/types/stdlib_test.go and
	// apply this to every AST node we can find to make sure it
	// doesn't crash.

	// TODO(adonovan): audit for ParenExpr safety, esp. since we
	// traverse up and down.

	// TODO(adonovan): if the users selects the "." in
	// "fmt.Fprintf()", they'll get an ambiguous selection error;
	// we won't even reach here.  Can we do better?

	// TODO(adonovan): describing a field within 'type T struct {...}'
	// describes the (anonymous) struct type and concludes "no methods".
	// We should ascend to the enclosing type decl, if any.

	for len(path) > 0 {
		switch n := path[0].(type) {
		case *ast.GenDecl:
			if len(n.Specs) == 1 {
				// Descend to sole {Import,Type,Value}Spec child.
				path = append([]ast.Node{n.Specs[0]}, path...)
				continue
			}
			return path, actionUnknown // uninteresting

		case *ast.FuncDecl:
			// Descend to function name.
			path = append([]ast.Node{n.Name}, path...)
			continue

		case *ast.ImportSpec:
			return path, actionPackage

		case *ast.ValueSpec:
			if len(n.Names) == 1 {
				// Descend to sole Ident child.
				path = append([]ast.Node{n.Names[0]}, path...)
				continue
			}
			return path, actionUnknown // uninteresting

		case *ast.TypeSpec:
			// Descend to type name.
			path = append([]ast.Node{n.Name}, path...)
			continue

		case ast.Stmt:
			return path, actionStmt

		case *ast.ArrayType,
			*ast.StructType,
			*ast.FuncType,
			*ast.InterfaceType,
			*ast.MapType,
			*ast.ChanType:
			return path, actionType

		case *ast.Comment, *ast.CommentGroup, *ast.File, *ast.KeyValueExpr, *ast.CommClause:
			return path, actionUnknown // uninteresting

		case *ast.Ellipsis:
			// Continue to enclosing node.
			// e.g. [...]T in ArrayType
			//      f(x...) in CallExpr
			//      f(x...T) in FuncType

		case *ast.Field:
			// TODO(adonovan): this needs more thought,
			// since fields can be so many things.
			if len(n.Names) == 1 {
				// Descend to sole Ident child.
				path = append([]ast.Node{n.Names[0]}, path...)
				continue
			}
			// Zero names (e.g. anon field in struct)
			// or multiple field or param names:
			// continue to enclosing field list.

		case *ast.FieldList:
			// Continue to enclosing node:
			// {Struct,Func,Interface}Type or FuncDecl.

		case *ast.BasicLit:
			if _, ok := path[1].(*ast.ImportSpec); ok {
				return path[1:], actionPackage
			}
			return path, actionExpr

		case *ast.SelectorExpr:
//.........这里部分代码省略.........

// NewTransformer returns a transformer based on the specified template,
// a package containing "before" and "after" functions as described
// in the package documentation.
//
func NewTransformer(fset *token.FileSet, template *loader.PackageInfo, verbose bool) (*Transformer, error) {
	// Check the template.
	beforeSig := funcSig(template.Pkg, "before")
	if beforeSig == nil {
		return nil, fmt.Errorf("no 'before' func found in template")
	}
	afterSig := funcSig(template.Pkg, "after")
	if afterSig == nil {
		return nil, fmt.Errorf("no 'after' func found in template")
	}

	// TODO(adonovan): should we also check the names of the params match?
	if !types.Identical(afterSig, beforeSig) {
		return nil, fmt.Errorf("before %s and after %s functions have different signatures",
			beforeSig, afterSig)
	}

	templateFile := template.Files[0]
	for _, imp := range templateFile.Imports {
		if imp.Name != nil && imp.Name.Name == "." {
			// Dot imports are currently forbidden.  We
			// make the simplifying assumption that all
			// imports are regular, without local renames.
			//TODO document
			return nil, fmt.Errorf("dot-import (of %s) in template", imp.Path.Value)
		}
	}
	var beforeDecl, afterDecl *ast.FuncDecl
	for _, decl := range templateFile.Decls {
		if decl, ok := decl.(*ast.FuncDecl); ok {
			switch decl.Name.Name {
			case "before":
				beforeDecl = decl
			case "after":
				afterDecl = decl
			}
		}
	}

	before, err := soleExpr(beforeDecl)
	if err != nil {
		return nil, fmt.Errorf("before: %s", err)
	}
	after, err := soleExpr(afterDecl)
	if err != nil {
		return nil, fmt.Errorf("after: %s", err)
	}

	wildcards := make(map[*types.Var]bool)
	for i := 0; i < beforeSig.Params().Len(); i++ {
		wildcards[beforeSig.Params().At(i)] = true
	}

	// checkExprTypes returns an error if Tb (type of before()) is not
	// safe to replace with Ta (type of after()).
	//
	// Only superficial checks are performed, and they may result in both
	// false positives and negatives.
	//
	// Ideally, we would only require that the replacement be assignable
	// to the context of a specific pattern occurrence, but the type
	// checker doesn't record that information and it's complex to deduce.
	// A Go type cannot capture all the constraints of a given expression
	// context, which may include the size, constness, signedness,
	// namedness or constructor of its type, and even the specific value
	// of the replacement.  (Consider the rule that array literal keys
	// must be unique.)  So we cannot hope to prove the safety of a
	// transformation in general.
	Tb := template.TypeOf(before)
	Ta := template.TypeOf(after)
	if types.AssignableTo(Tb, Ta) {
		// safe: replacement is assignable to pattern.
	} else if tuple, ok := Tb.(*types.Tuple); ok && tuple.Len() == 0 {
		// safe: pattern has void type (must appear in an ExprStmt).
	} else {
		return nil, fmt.Errorf("%s is not a safe replacement for %s", Ta, Tb)
	}

	tr := &Transformer{
		fset:           fset,
		verbose:        verbose,
		wildcards:      wildcards,
		allowWildcards: true,
		seenInfos:      make(map[*types.Info]bool),
		importedObjs:   make(map[types.Object]*ast.SelectorExpr),
		before:         before,
		after:          after,
	}

	// Combine type info from the template and input packages, and
	// type info for the synthesized ASTs too.  This saves us
	// having to book-keep where each ast.Node originated as we
	// construct the resulting hybrid AST.
	//
	// TODO(adonovan): move type utility methods of PackageInfo to
	// types.Info, or at least into go/types.typeutil.
//.........这里部分代码省略.........