Commit d8c815d8 authored by David Chase's avatar David Chase

cmd/compile: note escape of parts of closured-capture vars

Missed a case for closure calls (OCALLFUNC && indirect) in
esc.go:esccall.

Cleanup to runtime code for windows to more thoroughly hide
a technical escape.  Also made code pickier about failing
to late non-optional kernel32.dll.

Fixes #14409.

Change-Id: Ie75486a2c8626c4583224e02e4872c2875f7bca5
Reviewed-on: https://go-review.googlesource.com/20102
Run-TryBot: David Chase <drchase@google.com>
Reviewed-by: default avatarBrad Fitzpatrick <bradfitz@golang.org>
parent eb876dd8
......@@ -1458,6 +1458,11 @@ func esccall(e *EscState, n *Node, up *Node) {
if haspointers(t.Type) {
escassignSinkNilWhy(e, n, src, "receiver in indirect call")
}
} else { // indirect and OCALLFUNC = could be captured variables, too. (#14409)
ll := e.nodeEscState(n).Escretval.Slice()
for _, llN := range ll {
escassignDereference(e, llN, fn, e.stepAssign(nil, llN, fn, "captured by called closure"))
}
}
return
}
......
......@@ -110,23 +110,28 @@ func asmstdcall(fn unsafe.Pointer)
var asmstdcallAddr unsafe.Pointer
func windowsFindfunc(name []byte, lib uintptr) stdFunction {
f := stdcall2(_GetProcAddress, lib, uintptr(unsafe.Pointer(&name[0])))
return stdFunction(unsafe.Pointer(f))
}
func loadOptionalSyscalls() {
var buf [50]byte // large enough for longest string
strtoptr := func(s string) uintptr {
buf[copy(buf[:], s)] = 0 // nil-terminated for OS
return uintptr(noescape(unsafe.Pointer(&buf[0])))
}
l := stdcall1(_LoadLibraryA, strtoptr("kernel32.dll"))
findfunc := func(name string) stdFunction {
f := stdcall2(_GetProcAddress, l, strtoptr(name))
return stdFunction(unsafe.Pointer(f))
}
if l != 0 {
_AddDllDirectory = findfunc("AddDllDirectory")
_AddVectoredContinueHandler = findfunc("AddVectoredContinueHandler")
_GetQueuedCompletionStatusEx = findfunc("GetQueuedCompletionStatusEx")
_LoadLibraryExW = findfunc("LoadLibraryExW")
var (
kernel32dll = []byte("kernel32.dll\000")
addVectoredContinueHandler = []byte("AddVectoredContinueHandler\000")
getQueuedCompletionStatusEx = []byte("GetQueuedCompletionStatusEx\000")
addDllDirectory = []byte("AddDllDirectory\000")
loadLibraryExW = []byte("LoadLibraryExW\000")
)
k32 := stdcall1(_LoadLibraryA, uintptr(unsafe.Pointer(&kernel32dll[0])))
if k32 == 0 {
throw("kernel32.dll not found")
}
_AddDllDirectory = windowsFindfunc(addDllDirectory, k32)
_AddVectoredContinueHandler = windowsFindfunc(addVectoredContinueHandler, k32)
_GetQueuedCompletionStatusEx = windowsFindfunc(getQueuedCompletionStatusEx, k32)
_LoadLibraryExW = windowsFindfunc(loadLibraryExW, k32)
}
//go:nosplit
......
......@@ -145,3 +145,29 @@ func ClosureCallArgs15() {
// BAD: p should not escape here
}(&p) // ERROR "&p escapes to heap" "\(func literal\)\(&p\) escapes to heap"
}
func ClosureLeak1(s string) string { // ERROR "ClosureLeak1 s does not escape"
t := s + "YYYY" // ERROR "escapes to heap"
return ClosureLeak1a(t) // ERROR "ClosureLeak1 ... argument does not escape"
}
// See #14409 -- returning part of captured var leaks it.
func ClosureLeak1a(a ...string) string { // ERROR "leaking param: a to result ~r1 level=1"
return func() string { // ERROR "ClosureLeak1a func literal does not escape"
return a[0]
}()
}
func ClosureLeak2(s string) string { // ERROR "ClosureLeak2 s does not escape"
t := s + "YYYY" // ERROR "escapes to heap"
c := ClosureLeak2a(t) // ERROR "ClosureLeak2 ... argument does not escape"
return c
}
func ClosureLeak2a(a ...string) string { // ERROR "leaking param: a to result ~r1 level=1"
return ClosureLeak2b(func() string { // ERROR "ClosureLeak2a func literal does not escape"
return a[0]
})
}
func ClosureLeak2b(f func() string) string { // ERROR "leaking param: f to result ~r1 level=1"
return f()
}
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