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cmd/cgo: recognize unsafe.{StringData,SliceData}

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A simple call to unsafe.StringData can't contain any pointers.

When looking for field references, a call to unsafe.StringData or
unsafe.SliceData can be treated as a type conversion.

In order to make unsafe.SliceData useful, recognize slice expressions
when calling C functions.

Fixes #59954

Change-Id: I08a3ace7882073284c1d46a5210582a2521b0b4e
Reviewed-on: https://go-review.googlesource.com/c/go/+/493556
Run-TryBot: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
This commit is contained in:
Ian Lance Taylor 2023-05-08 12:45:42 -07:00 • committed by Gopher Robot
parent 2f1e643229
commit c7aa48eced
2 changed files with 124 additions and 4 deletions
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24
src/cmd/cgo/internal/testerrors/ptr_test.go
View file

@ -444,6 +444,28 @@ var ptrTests = []ptrTest{
body: `s := &S40{p: new(int)}; C.f40((*C.struct_S40i)(&s.a))`,
fail: false,
},
{
// Test that we handle unsafe.StringData.
name: "stringdata",
c: `void f41(void* p) {}`,
imports: []string{"unsafe"},
body: `s := struct { a [4]byte; p *int }{p: new(int)}; str := unsafe.String(&s.a[0], 4); C.f41(unsafe.Pointer(unsafe.StringData(str)))`,
fail: false,
},
{
name: "slicedata",
c: `void f42(void* p) {}`,
imports: []string{"unsafe"},
body: `s := []*byte{nil, new(byte)}; C.f42(unsafe.Pointer(unsafe.SliceData(s)))`,
fail: true,
},
{
name: "slicedata2",
c: `void f43(void* p) {}`,
imports: []string{"unsafe"},
body: `s := struct { a [4]byte; p *int }{p: new(int)}; C.f43(unsafe.Pointer(unsafe.SliceData(s.a[:])))`,
fail: false,
},
}
func TestPointerChecks(t *testing.T) {
@ -497,7 +519,7 @@ func buildPtrTests(t *testing.T, gopath string, cgocheck2 bool) (exe string) {
if err := os.MkdirAll(src, 0777); err != nil {
t.Fatal(err)
}
if err := os.WriteFile(filepath.Join(src, "go.mod"), []byte("module ptrtest"), 0666); err != nil {
if err := os.WriteFile(filepath.Join(src, "go.mod"), []byte("module ptrtest\ngo 1.20"), 0666); err != nil {
t.Fatal(err)
}