gotools/go/analysis/passes/cgocall/cgocall.go

const debug …

const Doc …

var Analyzer …

func run(pass *analysis.Pass) (interface{ … }

func checkCgo(fset *token.FileSet, f *ast.File, info *types.Info, reportf func(token.Pos, string, ...interface{ … }

// typeCheckCgoSourceFiles returns type-checked syntax trees for the raw
// cgo files of a package (those that import "C"). Such files are not
// Go, so there may be gaps in type information around C.f references.
//
// This checker was initially written in vet to inspect raw cgo source
// files using partial type information. However, Analyzers in the new
// analysis API are presented with the type-checked, "cooked" Go ASTs
// resulting from cgo-processing files, so we must choose between
// working with the cooked file generated by cgo (which was tried but
// proved fragile) or locating the raw cgo file (e.g. from //line
// directives) and working with that, as we now do.
//
// Specifically, we must type-check the raw cgo source files (or at
// least the subtrees needed for this analyzer) in an environment that
// simulates the rest of the already type-checked package.
//
// For example, for each raw cgo source file in the original package,
// such as this one:
//
//	package p
//	import "C"
//	import "fmt"
//	type T int
//	const k = 3
//	var x, y = fmt.Println()
//	func f() { ... }
//	func g() { ... C.malloc(k) ... }
//	func (T) f(int) string { ... }
//
// we synthesize a new ast.File, shown below, that dot-imports the
// original "cooked" package using a special name ("·this·"), so that all
// references to package members resolve correctly. (References to
// unexported names cause an "unexported" error, which we ignore.)
//
// To avoid shadowing names imported from the cooked package,
// package-level declarations in the new source file are modified so
// that they do not declare any names.
// (The cgocall analysis is concerned with uses, not declarations.)
// Specifically, type declarations are discarded;
// all names in each var and const declaration are blanked out;
// each method is turned into a regular function by turning
// the receiver into the first parameter;
// and all functions are renamed to "_".
//
//	package p
//	import . "·this·" // declares T, k, x, y, f, g, T.f
//	import "C"
//	import "fmt"
//	const _ = 3
//	var _, _ = fmt.Println()
//	func _() { ... }
//	func _() { ... C.malloc(k) ... }
//	func _(T, int) string { ... }
//
// In this way, the raw function bodies and const/var initializer
// expressions are preserved but refer to the "cooked" objects imported
// from "·this·", and none of the transformed package-level declarations
// actually declares anything. In the example above, the reference to k
// in the argument of the call to C.malloc resolves to "·this·".k, which
// has an accurate type.
//
// This approach could in principle be generalized to more complex
// analyses on raw cgo files. One could synthesize a "C" package so that
// C.f would resolve to "·this·"._C_func_f, for example. But we have
// limited ourselves here to preserving function bodies and initializer
// expressions since that is all that the cgocall analyzer needs.
func typeCheckCgoSourceFiles(fset *token.FileSet, pkg *types.Package, files []*ast.File, info *types.Info, sizes types.Sizes) ([]*ast.File, *types.Info, error) { … }

// cgoBaseType tries to look through type conversions involving
// unsafe.Pointer to find the real type. It converts:
//
//	unsafe.Pointer(x) => x
//	*(*unsafe.Pointer)(unsafe.Pointer(&x)) => x
func cgoBaseType(info *types.Info, arg ast.Expr) types.Type { … }

// typeOKForCgoCall reports whether the type of arg is OK to pass to a
// C function using cgo. This is not true for Go types with embedded
// pointers. m is used to avoid infinite recursion on recursive types.
func typeOKForCgoCall(t types.Type, m map[types.Type]bool) bool { … }

func isUnsafePointer(info *types.Info, e ast.Expr) bool { … }

type importerFunc …

func (f importerFunc) Import(path string) (*types.Package, error) { … }

// TODO(adonovan): make this a library function or method of Info.
func imported(info *types.Info, spec *ast.ImportSpec) *types.Package { … }