// 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:
if pkginfo.ObjectOf(n.Sel) == nil {
// TODO(adonovan): is this reachable?
return path, actionUnknown
}
// Descend to .Sel child.
path = append([]ast.Node{n.Sel}, path...)
continue
case *ast.Ident:
switch pkginfo.ObjectOf(n).(type) {
case *types.PkgName:
return path, actionPackage
case *types.Const:
return path, actionExpr
case *types.Label:
return path, actionStmt
case *types.TypeName:
return path, actionType
case *types.Var:
// For x in 'struct {x T}', return struct type, for now.
if _, ok := path[1].(*ast.Field); ok {
_ = path[2].(*ast.FieldList) // assertion
if _, ok := path[3].(*ast.StructType); ok {
return path[3:], actionType
}
}
return path, actionExpr
case *types.Func:
// For f in 'interface {f()}', return the interface type, for now.
if _, ok := path[1].(*ast.Field); ok {
_ = path[2].(*ast.FieldList) // assertion
if _, ok := path[3].(*ast.InterfaceType); ok {
return path[3:], actionType
}
}
return path, actionExpr
case *types.Builtin:
// For reference to built-in function, return enclosing call.
path = path[1:] // ascend to enclosing function call
continue
case *types.Nil:
return path, actionExpr
}
// No object.
switch path[1].(type) {
case *ast.SelectorExpr:
// Return enclosing selector expression.
return path[1:], actionExpr
case *ast.Field:
// TODO(adonovan): test this.
// e.g. all f in:
// struct { f, g int }
// interface { f() }
// func (f T) method(f, g int) (f, g bool)
//
// switch path[3].(type) {
// case *ast.FuncDecl:
// case *ast.StructType:
// case *ast.InterfaceType:
// }
//
// return path[1:], actionExpr
//
// Unclear what to do with these.
// Struct.Fields -- field
// Interface.Methods -- field
// FuncType.{Params.Results} -- actionExpr
// FuncDecl.Recv -- actionExpr
case *ast.File:
// 'package foo'
return path, actionPackage
case *ast.ImportSpec:
// TODO(adonovan): fix: why no package object? go/types bug?
return path[1:], actionPackage
default:
// e.g. blank identifier (go/types bug?)
// or y in "switch y := x.(type)" (go/types bug?)
// or code in a _test.go file that's not part of the package.
fmt.Printf("unknown reference %s in %T\n", n, path[1])
return path, actionUnknown
}
case *ast.StarExpr:
if pkginfo.IsType(n) {
return path, actionType
}
return path, actionExpr
case ast.Expr:
// All Expr but {BasicLit,Ident,StarExpr} are
// "true" expressions that evaluate to a value.
return path, actionExpr
}
// Ascend to parent.
path = path[1:]
}
return nil, actionUnknown // unreachable
}
// 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.
tr.info.Info = types.Info{
Types: make(map[ast.Expr]types.TypeAndValue),
Defs: make(map[*ast.Ident]types.Object),
Uses: make(map[*ast.Ident]types.Object),
Selections: make(map[*ast.SelectorExpr]*types.Selection),
}
mergeTypeInfo(&tr.info.Info, &template.Info)
// Compute set of imported objects required by after().
// TODO reject dot-imports in pattern
ast.Inspect(after, func(n ast.Node) bool {
if n, ok := n.(*ast.SelectorExpr); ok {
if _, ok := tr.info.Selections[n]; !ok {
// qualified ident
obj := tr.info.Uses[n.Sel]
tr.importedObjs[obj] = n
return false // prune
}
}
return true // recur
})
return tr, nil
}