From e94544cf012535da6b3c9e735bc4026e2db1c99c Mon Sep 17 00:00:00 2001 From: Matthew Dempsky Date: Wed, 19 Aug 2020 21:39:12 -0700 Subject: cmd/compile: fix checkptr handling of &^ checkptr has code to recognize &^ expressions, but it didn't take into account that "p &^ x" gets rewritten to "p & ^x" during walk, which resulted in false positive diagnostics. This CL changes walkexpr to mark OANDNOT expressions with Implicit when they're rewritten to OAND, so that walkCheckPtrArithmetic can still recognize them later. It would be slightly more idiomatic to instead mark the OBITNOT expression as Implicit (as it's a compiler-generated Node), but the OBITNOT expression might get constant folded. It's not worth the extra complexity/subtlety of relying on n.Right.Orig, so we set Implicit on the OAND node instead. To atone for this transgression, I add documentation for nodeImplicit. Fixes #40917. Change-Id: I386304171ad299c530e151e5924f179e9a5fd5b8 Reviewed-on: https://go-review.googlesource.com/c/go/+/249477 Run-TryBot: Matthew Dempsky TryBot-Result: Gobot Gobot Reviewed-by: Keith Randall Reviewed-by: Cuong Manh Le --- src/runtime/testdata/testprog/checkptr.go | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'src/runtime/testdata') diff --git a/src/runtime/testdata/testprog/checkptr.go b/src/runtime/testdata/testprog/checkptr.go index 45e6fb1aa5..e0a2794f4c 100644 --- a/src/runtime/testdata/testprog/checkptr.go +++ b/src/runtime/testdata/testprog/checkptr.go @@ -10,6 +10,7 @@ func init() { register("CheckPtrAlignmentNoPtr", CheckPtrAlignmentNoPtr) register("CheckPtrAlignmentPtr", CheckPtrAlignmentPtr) register("CheckPtrArithmetic", CheckPtrArithmetic) + register("CheckPtrArithmetic2", CheckPtrArithmetic2) register("CheckPtrSize", CheckPtrSize) register("CheckPtrSmall", CheckPtrSmall) } @@ -32,6 +33,13 @@ func CheckPtrArithmetic() { sink2 = (*int)(unsafe.Pointer(i)) } +func CheckPtrArithmetic2() { + var x [2]int64 + p := unsafe.Pointer(&x[1]) + var one uintptr = 1 + sink2 = unsafe.Pointer(uintptr(p) & ^one) +} + func CheckPtrSize() { p := new(int64) sink2 = p -- cgit v1.3