gotools/go/internal/cgo/cgo.go

// ProcessFiles invokes the cgo preprocessor on bp.CgoFiles, parses
// the output and returns the resulting ASTs.
func ProcessFiles(bp *build.Package, fset *token.FileSet, DisplayPath func(path string) string, mode parser.Mode) ([]*ast.File, error) { … }

var cgoRe …

// Run invokes the cgo preprocessor on bp.CgoFiles and returns two
// lists of files: the resulting processed files (in temporary
// directory tmpdir) and the corresponding names of the unprocessed files.
//
// Run is adapted from (*builder).cgo in
// $GOROOT/src/cmd/go/build.go, but these features are unsupported:
// Objective C, CGOPKGPATH, CGO_FLAGS.
//
// If useabs is set to true, absolute paths of the bp.CgoFiles will be passed in
// to the cgo preprocessor. This in turn will set the // line comments
// referring to those files to use absolute paths. This is needed for
// go/packages using the legacy go list support so it is able to find
// the original files.
func Run(bp *build.Package, pkgdir, tmpdir string, useabs bool) (files, displayFiles []string, err error) { … }

// Return the flags to use when invoking the C or C++ compilers, or cgo.
func cflags(p *build.Package, def bool) (cppflags, cflags, cxxflags, ldflags []string) { … }

// envList returns the value of the given environment variable broken
// into fields, using the default value when the variable is empty.
func envList(key, def string) []string { … }

// stringList's arguments should be a sequence of string or []string values.
// stringList flattens them into a single []string.
func stringList(args ...interface{ … }