From 840fad13ecd974efebe4fa25d4e444df5ec8041d Mon Sep 17 00:00:00 2001 From: Matthew Dempsky Date: Thu, 7 Dec 2017 23:04:50 -0800 Subject: [PATCH] cmd/compile: fix unsafe.Pointer liveness for Syscall-like functions The package unsafe docs say it's safe to convert an unsafe.Pointer to uintptr in the argument list to an assembly function, but it was erroneously only detecting normal pointers converted to unsafe.Pointer and then to intptr. Fixes #23051. Change-Id: Id1be19f6d8f26f2d17ba815191717d2f4f899732 Reviewed-on: https://go-review.googlesource.com/82817 Run-TryBot: Matthew Dempsky TryBot-Result: Gobot Gobot Reviewed-by: Ian Lance Taylor --- src/cmd/compile/internal/gc/order.go | 4 ++-- test/live_syscall.go | 12 ++++++++++++ 2 files changed, 14 insertions(+), 2 deletions(-) diff --git a/src/cmd/compile/internal/gc/order.go b/src/cmd/compile/internal/gc/order.go index de89adf0e0..4b24be893a 100644 --- a/src/cmd/compile/internal/gc/order.go +++ b/src/cmd/compile/internal/gc/order.go @@ -395,11 +395,11 @@ func ordercall(n *Node, order *Order) { // by copying it into a temp and marking that temp // still alive when we pop the temp stack. xp := n.List.Addr(i) - for (*xp).Op == OCONVNOP && !(*xp).Type.IsPtr() { + for (*xp).Op == OCONVNOP && !(*xp).Type.IsUnsafePtr() { xp = &(*xp).Left } x := *xp - if x.Type.IsPtr() { + if x.Type.IsUnsafePtr() { x = ordercopyexpr(x, x.Type, order, 0) x.Name.SetKeepalive(true) *xp = x diff --git a/test/live_syscall.go b/test/live_syscall.go index f693e9357a..6d954653cc 100644 --- a/test/live_syscall.go +++ b/test/live_syscall.go @@ -26,3 +26,15 @@ func h() { var v int syscall.Syscall(0, 1, uintptr(unsafe.Pointer(&v)), 2) // ERROR "live at call to Syscall: .?autotmp" "h &v does not escape" } + +func i() { + var t int + p := unsafe.Pointer(&t) // ERROR "i &t does not escape" + f(uintptr(p)) // ERROR "live at call to f: .?autotmp" +} + +func j() { + var v int + p := unsafe.Pointer(&v) // ERROR "j &v does not escape" + syscall.Syscall(0, 1, uintptr(p), 2) // ERROR "live at call to Syscall: .?autotmp" +} -- 2.50.0