From e104ebfeabf575d9e33bb56decd6eceb40f041ce Mon Sep 17 00:00:00 2001 From: Ian Lance Taylor Date: Mon, 28 Jan 2019 12:31:55 -0800 Subject: [release-branch.go1.11] cmd/cgo: disable GCC 9 warnings triggered by cgo code GCC 9 has started emitting warnings when taking the address of a field in a packed struct may cause a misaligned pointer. We use packed structs in cgo to ensure that our field layout matches the C compiler's layout. Our pointers are always aligned, so disable the warning Updates #29962 Fixes #29967 Change-Id: I7e290a7cf694a2c2958529e340ebed9fcd62089c Reviewed-on: https://go-review.googlesource.com/c/159859 Run-TryBot: Ian Lance Taylor TryBot-Result: Gobot Gobot Reviewed-by: Bryan C. Mills (cherry picked from commit f2a416b90ac68596ea05b97cefa8c72e7416e98f) Reviewed-on: https://go-review.googlesource.com/c/160449 Run-TryBot: Brad Fitzpatrick Reviewed-by: Brad Fitzpatrick --- src/cmd/cgo/out.go | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/src/cmd/cgo/out.go b/src/cmd/cgo/out.go index 89598c96e8..bbed5d598f 100644 --- a/src/cmd/cgo/out.go +++ b/src/cmd/cgo/out.go @@ -740,6 +740,10 @@ func (p *Package) writeExports(fgo2, fm, fgcc, fgcch io.Writer) { fmt.Fprintf(fgcc, "#include \n") fmt.Fprintf(fgcc, "#include \"_cgo_export.h\"\n\n") + // We use packed structs, but they are always aligned. + fmt.Fprintf(fgcc, "#pragma GCC diagnostic ignored \"-Wpragmas\"\n") + fmt.Fprintf(fgcc, "#pragma GCC diagnostic ignored \"-Waddress-of-packed-member\"\n") + fmt.Fprintf(fgcc, "extern void crosscall2(void (*fn)(void *, int, __SIZE_TYPE__), void *, int, __SIZE_TYPE__);\n") fmt.Fprintf(fgcc, "extern __SIZE_TYPE__ _cgo_wait_runtime_init_done();\n") fmt.Fprintf(fgcc, "extern void _cgo_release_context(__SIZE_TYPE__);\n\n") @@ -1340,6 +1344,10 @@ __cgo_size_assert(double, 8) extern char* _cgo_topofstack(void); +/* We use packed structs, but they are always aligned. */ +#pragma GCC diagnostic ignored "-Wpragmas" +#pragma GCC diagnostic ignored "-Waddress-of-packed-member" + #include #include ` -- cgit v1.2.3-54-g00ecf