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| author | Matthew Dempsky <mdempsky@google.com> | 2021-06-25 11:07:28 -0700 |
|---|---|---|
| committer | Matthew Dempsky <mdempsky@google.com> | 2021-06-28 23:31:13 +0000 |
| commit | 4bb0847b088eb3eb6122a18a87e1ca7756281dcc (patch) | |
| tree | 9baa7b329f0ec4cfdc2f80a833e14070794fe76c /src/cmd/compile/internal/typecheck | |
| parent | 1519271a939ad27da133318dc4bde7e6a41a35b5 (diff) | |
| download | go-4bb0847b088eb3eb6122a18a87e1ca7756281dcc.tar.gz go-4bb0847b088eb3eb6122a18a87e1ca7756281dcc.zip | |
cmd/compile,runtime: change unsafe.Slice((*T)(nil), 0) to return []T(nil)
This CL removes the unconditional OCHECKNIL check added in
walkUnsafeSlice by instead passing it as a pointer to
runtime.unsafeslice, and hiding the check behind a `len == 0` check.
While here, this CL also implements checkptr functionality for
unsafe.Slice and disallows use of unsafe.Slice with //go:notinheap
types.
Updates #46742.
Change-Id: I743a445ac124304a4d7322a7fe089c4a21b9a655
Reviewed-on: https://go-review.googlesource.com/c/go/+/331070
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Trust: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
Diffstat (limited to 'src/cmd/compile/internal/typecheck')
| -rw-r--r-- | src/cmd/compile/internal/typecheck/builtin.go | 5 | ||||
| -rw-r--r-- | src/cmd/compile/internal/typecheck/builtin/runtime.go | 5 | ||||
| -rw-r--r-- | src/cmd/compile/internal/typecheck/func.go | 7 |
3 files changed, 13 insertions, 4 deletions
diff --git a/src/cmd/compile/internal/typecheck/builtin.go b/src/cmd/compile/internal/typecheck/builtin.go index 67a894c7ed..833b17b414 100644 --- a/src/cmd/compile/internal/typecheck/builtin.go +++ b/src/cmd/compile/internal/typecheck/builtin.go @@ -138,6 +138,7 @@ var runtimeDecls = [...]struct { {"growslice", funcTag, 116}, {"unsafeslice", funcTag, 117}, {"unsafeslice64", funcTag, 118}, + {"unsafeslicecheckptr", funcTag, 118}, {"memmove", funcTag, 119}, {"memclrNoHeapPointers", funcTag, 120}, {"memclrHasPointers", funcTag, 120}, @@ -341,8 +342,8 @@ func runtimeTypes() []*types.Type { typs[114] = newSig(params(typs[1], typs[15], typs[15], typs[7]), params(typs[7])) typs[115] = types.NewSlice(typs[2]) typs[116] = newSig(params(typs[1], typs[115], typs[15]), params(typs[115])) - typs[117] = newSig(params(typs[1], typs[15]), nil) - typs[118] = newSig(params(typs[1], typs[22]), nil) + typs[117] = newSig(params(typs[1], typs[7], typs[15]), nil) + typs[118] = newSig(params(typs[1], typs[7], typs[22]), nil) typs[119] = newSig(params(typs[3], typs[3], typs[5]), nil) typs[120] = newSig(params(typs[7], typs[5]), nil) typs[121] = newSig(params(typs[3], typs[3], typs[5]), params(typs[6])) diff --git a/src/cmd/compile/internal/typecheck/builtin/runtime.go b/src/cmd/compile/internal/typecheck/builtin/runtime.go index ebeaeae79e..2b29ea3c08 100644 --- a/src/cmd/compile/internal/typecheck/builtin/runtime.go +++ b/src/cmd/compile/internal/typecheck/builtin/runtime.go @@ -183,8 +183,9 @@ func makeslice(typ *byte, len int, cap int) unsafe.Pointer func makeslice64(typ *byte, len int64, cap int64) unsafe.Pointer func makeslicecopy(typ *byte, tolen int, fromlen int, from unsafe.Pointer) unsafe.Pointer func growslice(typ *byte, old []any, cap int) (ary []any) -func unsafeslice(typ *byte, len int) -func unsafeslice64(typ *byte, len int64) +func unsafeslice(typ *byte, ptr unsafe.Pointer, len int) +func unsafeslice64(typ *byte, ptr unsafe.Pointer, len int64) +func unsafeslicecheckptr(typ *byte, ptr unsafe.Pointer, len int64) func memmove(to *any, frm *any, length uintptr) func memclrNoHeapPointers(ptr unsafe.Pointer, n uintptr) diff --git a/src/cmd/compile/internal/typecheck/func.go b/src/cmd/compile/internal/typecheck/func.go index a6dfbbf569..fbcc784627 100644 --- a/src/cmd/compile/internal/typecheck/func.go +++ b/src/cmd/compile/internal/typecheck/func.go @@ -1018,7 +1018,14 @@ func tcUnsafeSlice(n *ir.BinaryExpr) *ir.BinaryExpr { t := n.X.Type() if !t.IsPtr() { base.Errorf("first argument to unsafe.Slice must be pointer; have %L", t) + } else if t.Elem().NotInHeap() { + // TODO(mdempsky): This can be relaxed, but should only affect the + // Go runtime itself. End users should only see //go:notinheap + // types due to incomplete C structs in cgo, and those types don't + // have a meaningful size anyway. + base.Errorf("unsafe.Slice of incomplete (or unallocatable) type not allowed") } + if !checkunsafeslice(&n.Y) { n.SetType(nil) return n |