Merge from trunk revision aa8f4242efc99f24de73c59d53996f28db28c13f.

3 files changed, 25 insertions, 7 deletions

diff --git a/libgo/go/runtime/ffi.go b/libgo/go/runtime/ffi.go
index cd8479e..86ce5b8 100644
--- a/libgo/go/runtime/ffi.go
+++ b/libgo/go/runtime/ffi.go
@@ -4,6 +4,7 @@
 
 // Only build this file if libffi is supported.
 
+//go:build libffi
 // +build libffi
 
 package runtime
@@ -221,9 +222,6 @@ func stringToFFI() *__ffi_type {
 // structToFFI returns an ffi_type for a Go struct type.
 func structToFFI(typ *structtype) *__ffi_type {
 	c := len(typ.fields)
-	if c == 0 {
-		return emptyStructToFFI()
-	}
 	if typ.typ.kind&kindDirectIface != 0 {
 		return ffi_type_pointer()
 	}
@@ -231,6 +229,7 @@ func structToFFI(typ *structtype) *__ffi_type {
 	fields := make([]*__ffi_type, 0, c+1)
 	checkPad := false
 	lastzero := false
+	sawnonzero := false
 	for i, v := range typ.fields {
 		// Skip zero-sized fields; they confuse libffi,
 		// and there is no value to pass in any case.
@@ -239,10 +238,13 @@ func structToFFI(typ *structtype) *__ffi_type {
 		// next field.
 		if v.typ.size == 0 {
 			checkPad = true
-			lastzero = true
+			if v.name == nil || *v.name != "_" {
+				lastzero = true
+			}
 			continue
 		}
 		lastzero = false
+		sawnonzero = true
 
 		if checkPad {
 			off := uintptr(0)
@@ -263,6 +265,10 @@ func structToFFI(typ *structtype) *__ffi_type {
 		fields = append(fields, typeToFFI(v.typ))
 	}
 
+	if !sawnonzero {
+		return emptyStructToFFI()
+	}
+
 	if lastzero {
 		// The compiler adds one byte padding to non-empty struct ending
 		// with a zero-sized field (types.cc:get_backend_struct_fields).
diff --git a/libgo/go/runtime/mem_gccgo.go b/libgo/go/runtime/mem_gccgo.go
index fa3389d..1e84f4f 100644
--- a/libgo/go/runtime/mem_gccgo.go
+++ b/libgo/go/runtime/mem_gccgo.go
@@ -15,7 +15,7 @@ import (
 //go:linkname sysFree
 
 //extern mmap
-func sysMmap(addr unsafe.Pointer, n uintptr, prot, flags, fd int32, off uintptr) unsafe.Pointer
+func sysMmap(addr unsafe.Pointer, n uintptr, prot, flags, fd int32, off _libgo_off_t_type) unsafe.Pointer
 
 //extern munmap
 func munmap(addr unsafe.Pointer, length uintptr) int32
@@ -38,7 +38,7 @@ func init() {
 }
 
 func mmap(addr unsafe.Pointer, n uintptr, prot, flags, fd int32, off uintptr) (unsafe.Pointer, int) {
-	p := sysMmap(addr, n, prot, flags, fd, off)
+	p := sysMmap(addr, n, prot, flags, fd, _libgo_off_t_type(off))
 	if uintptr(p) == _MAP_FAILED {
 		return nil, errno()
 	}
@@ -47,6 +47,7 @@ func mmap(addr unsafe.Pointer, n uintptr, prot, flags, fd int32, off uintptr) (u
 
 // Don't split the stack as this method may be invoked without a valid G, which
 // prevents us from allocating more stack.
+//
 //go:nosplit
 func sysAlloc(n uintptr, sysStat *sysMemStat) unsafe.Pointer {
 	p, err := mmap(nil, n, _PROT_READ|_PROT_WRITE, _MAP_ANON|_MAP_PRIVATE, mmapFD, 0)
@@ -165,6 +166,7 @@ func sysHugePage(v unsafe.Pointer, n uintptr) {
 
 // Don't split the stack as this function may be invoked without a valid G,
 // which prevents us from allocating more stack.
+//
 //go:nosplit
 func sysFree(v unsafe.Pointer, n uintptr, sysStat *sysMemStat) {
 	sysStat.add(-int64(n))
diff --git a/libgo/go/runtime/os_linux.go b/libgo/go/runtime/os_linux.go
index 96fb178..2b2d827 100644
--- a/libgo/go/runtime/os_linux.go
+++ b/libgo/go/runtime/os_linux.go
@@ -22,6 +22,12 @@ type mOS struct {
 	profileTimerValid uint32
 }
 
+// setSigeventTID is written in C to set the sigev_notify_thread_id
+// field of a sigevent struct.
+//
+//go:noescape
+func setSigeventTID(*_sigevent, int32)
+
 func getProcID() uint64 {
 	return uint64(gettid())
 }
@@ -52,9 +58,12 @@ const (
 )
 
 // Atomically,
+//
 //	if(*addr == val) sleep
+//
 // Might be woken up spuriously; that's allowed.
 // Don't sleep longer than ns; ns < 0 means forever.
+//
 //go:nosplit
 func futexsleep(addr *uint32, val uint32, ns int64) {
 	// Some Linux kernels have a bug where futex of
@@ -73,6 +82,7 @@ func futexsleep(addr *uint32, val uint32, ns int64) {
 }
 
 // If any procs are sleeping on addr, wake up at most cnt.
+//
 //go:nosplit
 func futexwakeup(addr *uint32, cnt uint32) {
 	ret := futex(unsafe.Pointer(addr), _FUTEX_WAKE_PRIVATE, cnt, nil, nil, 0)
@@ -365,7 +375,7 @@ func setThreadCPUProfiler(hz int32) {
 	var sevp _sigevent
 	sevp.sigev_notify = _SIGEV_THREAD_ID
 	sevp.sigev_signo = _SIGPROF
-	*((*int32)(unsafe.Pointer(&sevp._sigev_un))) = int32(mp.procid)
+	setSigeventTID(&sevp, int32(mp.procid))
 	ret := timer_create(_CLOCK_THREAD_CPUTIME_ID, &sevp, &timerid)
 	if ret != 0 {
 		// If we cannot create a timer for this M, leave profileTimerValid false