Austin Clements <******@****.***> 1683216807 -0400

stdout a\.go
[compiler:gc] stdout -count=3 $GOCACHE
[compiler:gccgo] stdout -count=2 $GOCACHE

-- go.mod --
module example

go 1.16

-- swig/a.go --
package swig

    println(C.INT_MAX)
}

-- cgo/pkg_notcgo.go --
//go:build !cgo
// +build !cgo

package cgopkg

func F() {
    println(0)
}

-- swig/pkg.go --
package swigpkg

The second is the SWIG program, which is a general tool for
interfacing between languages. For information on SWIG see
http://swig.org/. When running go build, any file with a .swig
extension will be passed to SWIG. Any file with a .swigcxx extension
will be passed to SWIG with the -c++ option.

When either cgo or SWIG is used, go build will pass any .c, .m, .s, .S
or .sx files to the C compiler, and any .cc, .cpp, .cxx files to the C++

	case ".h", ".hh", ".hpp", ".hxx":
		return &p.HFiles
	case ".f", ".F", ".for", ".f90":
		return &p.FFiles
	case ".s", ".S", ".sx":
		return &p.SFiles
	case ".swig":
		return &p.SwigFiles
	case ".swigcxx":
		return &p.SwigCXXFiles
	case ".syso":
		return &p.SysoFiles
	}
	return nil
}

var errNoModules = errors.New("not using modules")

func findImportComment(data []byte) (s string, line int) {

        FFiles            []string   // .f, .F, .for and .f90 Fortran source files
        SFiles            []string   // .s source files
        SwigFiles         []string   // .swig files
        SwigCXXFiles      []string   // .swigcxx files
        SysoFiles         []string   // .syso object files to add to archive
        TestGoFiles       []string   // _test.go files in package
        XTestGoFiles      []string   // _test.go files outside package

	FFiles            []string // .f, .F, .for and .f90 Fortran source files
	SFiles            []string // .s source files
	SwigFiles         []string // .swig files
	SwigCXXFiles      []string // .swigcxx files
	SysoFiles         []string // .syso system object files to add to archive

	// Cgo directives
	CgoCFLAGS    []string // Cgo CFLAGS directives
	CgoCPPFLAGS  []string // Cgo CPPFLAGS directives

//	    FFiles            []string   // .f, .F, .for and .f90 Fortran source files
//	    SFiles            []string   // .s source files
//	    SwigFiles         []string   // .swig files
//	    SwigCXXFiles      []string   // .swigcxx files
//	    SysoFiles         []string   // .syso object files to add to archive
//	    TestGoFiles       []string   // _test.go files in package
//	    XTestGoFiles      []string   // _test.go files outside package
//

			}
			if ba, ok := a.Actor.(*buildActor); ok && ba.covMetaFileName != "" {
				b.cacheObjdirFile(a, cache.Default(), ba.covMetaFileName)
			}
		}
	}

	// Run SWIG on each .swig and .swigcxx file.
	// Each run will generate two files, a .go file and a .c or .cxx file.
	// The .go file will use import "C" and is to be processed by cgo.
	// For -cover test or build runs, this needs to happen after the cover

	SFiles            []string `json:",omitempty"` // .s source files
	SwigFiles         []string `json:",omitempty"` // .swig files
	SwigCXXFiles      []string `json:",omitempty"` // .swigcxx files
	SysoFiles         []string `json:",omitempty"` // .syso system object files added to package

	// Embedded files
	EmbedPatterns []string `json:",omitempty"` // //go:embed patterns