From: Matthew Dempsky Date: Fri, 26 Jun 2020 18:26:33 +0000 (-0700) Subject: cmd/cgo: prevent redeclaration of _Ctype_void when C.void is used X-Git-Tag: go1.15rc1~55 X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=a295d59d10d87ea882ddc8db6919a278b3a67d01;p=gostls13.git cmd/cgo: prevent redeclaration of _Ctype_void when C.void is used CL 230037 changed cmd/cgo to emit "type _Ctype_foo = bar" aliases for all C.foo types mentioned in the original Go source files. However, cmd/cgo already emits an appropriate type definition for _Ctype_void. So if a source file explicitly mentions C.void, this resulted in _Ctype_void being declared multiple times. This CL fixes the issue by suppressing the "type _Ctype_void = _Ctype_void" alias before printing it. This should be safe because _Ctype_void is the only type that's specially emitted in out.go at the moment. A somewhat better fix might be to fix how _Ctype_void is declared in the cmd/cgo "frontend", but this is a less invasive fix. Fixes #39877. Change-Id: Ief264b3847c8ef8df1478a6333647ff2cf09b63d Reviewed-on: https://go-review.googlesource.com/c/go/+/240180 Run-TryBot: Matthew Dempsky Reviewed-by: Ian Lance Taylor TryBot-Result: Gobot Gobot --- diff --git a/misc/cgo/test/test.go b/misc/cgo/test/test.go index b5009d43ce..8c69ad91ac 100644 --- a/misc/cgo/test/test.go +++ b/misc/cgo/test/test.go @@ -2200,3 +2200,7 @@ func test32579(t *testing.T) { // issue 38649 var issue38649 C.netbsd_gid = 42 + +// issue 39877 + +var issue39877 *C.void = nil diff --git a/src/cmd/cgo/out.go b/src/cmd/cgo/out.go index 6b40a255d5..6c221473e0 100644 --- a/src/cmd/cgo/out.go +++ b/src/cmd/cgo/out.go @@ -98,6 +98,11 @@ func (p *Package) writeDefs() { typedefNames := make([]string, 0, len(typedef)) for name := range typedef { + if name == "_Ctype_void" { + // We provide an appropriate declaration for + // _Ctype_void below (#39877). + continue + } typedefNames = append(typedefNames, name) } sort.Strings(typedefNames)