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| author | Ian Lance Taylor <iant@golang.org> | 2020-09-01 17:01:00 -0700 |
|---|---|---|
| committer | Ian Lance Taylor <iant@golang.org> | 2020-09-16 03:02:13 +0000 |
| commit | eaa97fbf20baffac713ed1b780f864a6fee54ab6 (patch) | |
| tree | 031393ccd793d62fa819ad97378fb281206e915b /misc | |
| parent | b6dbaef68fdbb3f14387e4c32a8890144220f54e (diff) | |
| download | go-eaa97fbf20baffac713ed1b780f864a6fee54ab6.tar.gz go-eaa97fbf20baffac713ed1b780f864a6fee54ab6.zip | |
cmd/cgo: don't translate bitfields into Go fields
The cgo tool would sometimes emit a bitfield at an offset that did not
correspond to the C offset, such as for the example in the new test.
Change-Id: I61b2ca10ee44a42f81c13ed12865f2060168fed5
Reviewed-on: https://go-review.googlesource.com/c/go/+/252378
Trust: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Diffstat (limited to 'misc')
| -rw-r--r-- | misc/cgo/testgodefs/testdata/bitfields.go | 31 | ||||
| -rw-r--r-- | misc/cgo/testgodefs/testdata/main.go | 28 | ||||
| -rw-r--r-- | misc/cgo/testgodefs/testgodefs_test.go | 1 |
3 files changed, 60 insertions, 0 deletions
diff --git a/misc/cgo/testgodefs/testdata/bitfields.go b/misc/cgo/testgodefs/testdata/bitfields.go new file mode 100644 index 0000000000..6a9724dcd1 --- /dev/null +++ b/misc/cgo/testgodefs/testdata/bitfields.go @@ -0,0 +1,31 @@ +// Copyright 2020 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. +// +// +build ignore + +package main + +// This file tests that we don't generate an incorrect field location +// for a bitfield that appears aligned. + +/* +struct bitfields { + unsigned int B1 : 5; + unsigned int B2 : 1; + unsigned int B3 : 1; + unsigned int B4 : 1; + unsigned int Short1 : 16; // misaligned on 8 bit boundary + unsigned int B5 : 1; + unsigned int B6 : 1; + unsigned int B7 : 1; + unsigned int B8 : 1; + unsigned int B9 : 1; + unsigned int B10 : 3; + unsigned int Short2 : 16; // alignment is OK + unsigned int Short3 : 16; // alignment is OK +}; +*/ +import "C" + +type bitfields C.struct_bitfields diff --git a/misc/cgo/testgodefs/testdata/main.go b/misc/cgo/testgodefs/testdata/main.go index 2e1ad3376a..4a3f6a701c 100644 --- a/misc/cgo/testgodefs/testdata/main.go +++ b/misc/cgo/testgodefs/testdata/main.go @@ -4,6 +4,12 @@ package main +import ( + "fmt" + "os" + "reflect" +) + // Test that the struct field in anonunion.go was promoted. var v1 T var v2 = v1.L @@ -23,4 +29,26 @@ var v7 = S{} var _ = issue38649{X: 0} func main() { + pass := true + + // The Go translation of bitfields should not have any of the + // bitfield types. The order in which bitfields are laid out + // in memory is implementation defined, so we can't easily + // know how a bitfield should correspond to a Go type, even if + // it appears to be aligned correctly. + bitfieldType := reflect.TypeOf(bitfields{}) + check := func(name string) { + _, ok := bitfieldType.FieldByName(name) + if ok { + fmt.Fprintf(os.Stderr, "found unexpected bitfields field %s\n", name) + pass = false + } + } + check("Short1") + check("Short2") + check("Short3") + + if !pass { + os.Exit(1) + } } diff --git a/misc/cgo/testgodefs/testgodefs_test.go b/misc/cgo/testgodefs/testgodefs_test.go index e4085f9ca8..4c2312c1c8 100644 --- a/misc/cgo/testgodefs/testgodefs_test.go +++ b/misc/cgo/testgodefs/testgodefs_test.go @@ -19,6 +19,7 @@ import ( // import "C" block. Add more tests here. var filePrefixes = []string{ "anonunion", + "bitfields", "issue8478", "fieldtypedef", "issue37479", |