Implement new syscall package.

Calls to library functions now use entersyscall and
exitsyscall as appropriate.  This is a first step toward
multiplexing goroutines onto threads.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@180345 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 159 insertions, 0 deletions

diff --git a/libgo/go/syscall/syscall_unix.go b/libgo/go/syscall/syscall_unix.go
new file mode 100644
index 000000000000..c734b2cf06aa
--- /dev/null
+++ b/libgo/go/syscall/syscall_unix.go
@@ -0,0 +1,159 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build darwin freebsd linux openbsd
+
+package syscall
+
+import (
+	"sync"
+	"unsafe"
+)
+
+var (
+	Stdin  = 0
+	Stdout = 1
+	Stderr = 2
+)
+
+func c_syscall32(trap int32, a1, a2, a3, a4, a5, a6 int32) int32 __asm__ ("syscall");
+func c_syscall64(trap int64, a1, a2, a3, a4, a5, a6 int64) int64 __asm__ ("syscall");
+
+// Do a system call.  We look at the size of uintptr to see how to pass
+// the arguments, so that we don't pass a 64-bit value when the function
+// expects a 32-bit one.
+func Syscall(trap, a1, a2, a3 uintptr) (r1, r2, err uintptr) {
+	entersyscall()
+	var r uintptr
+	if unsafe.Sizeof(r) == 4 {
+		r1 := c_syscall32(int32(trap), int32(a1), int32(a2), int32(a3), 0, 0, 0)
+		r = uintptr(r1)
+	} else {
+		r1 := c_syscall64(int64(trap), int64(a1), int64(a2), int64(a3), 0, 0, 0)
+		r = uintptr(r1)
+	}
+	errno := GetErrno()
+	exitsyscall()
+	return r, 0, uintptr(errno)
+}
+
+func Syscall6(trap, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2, err uintptr) {
+	entersyscall()
+	var r uintptr
+	if unsafe.Sizeof(r) == 4 {
+		r1 := c_syscall32(int32(trap), int32(a1), int32(a2), int32(a3),
+    			int32(a4), int32(a5), int32(a6))
+		r = uintptr(r1)
+	} else {
+		r1 := c_syscall64(int64(trap), int64(a1), int64(a2), int64(a3),
+			int64(a4), int64(a5), int64(a6))
+		r = uintptr(r1)
+	}
+	errno := GetErrno()
+	exitsyscall()
+	return r, 0, uintptr(errno)
+}
+
+func RawSyscall(trap, a1, a2, a3 uintptr) (r1, r2, err uintptr) {
+	var r uintptr
+	if unsafe.Sizeof(r) == 4 {
+		r1 := c_syscall32(int32(trap), int32(a1), int32(a2), int32(a3), 0, 0, 0)
+		r = uintptr(r1)
+	} else {
+		r1 := c_syscall64(int64(trap), int64(a1), int64(a2), int64(a3), 0, 0, 0)
+		r = uintptr(r1)
+	}
+	errno := GetErrno()
+	return r, 0, uintptr(errno)
+}
+
+func RawSyscall6(trap, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2, err uintptr) {
+	var r uintptr
+	if unsafe.Sizeof(r) == 4 {
+		r1 := c_syscall32(int32(trap), int32(a1), int32(a2), int32(a3),
+    			int32(a4), int32(a5), int32(a6))
+		r = uintptr(r1)
+	} else {
+		r1 := c_syscall64(int64(trap), int64(a1), int64(a2), int64(a3),
+			int64(a4), int64(a5), int64(a6))
+		r = uintptr(r1)
+	}
+	errno := GetErrno()
+	return r, 0, uintptr(errno)
+}
+
+// Mmap manager, for use by operating system-specific implementations.
+// Gccgo only has one implementation but we do this to correspond to gc.
+
+type mmapper struct {
+	sync.Mutex
+	active map[*byte][]byte // active mappings; key is last byte in mapping
+	mmap   func(addr, length uintptr, prot, flags, fd int, offset int64) (uintptr, int)
+	munmap func(addr uintptr, length uintptr) int
+}
+
+func (m *mmapper) Mmap(fd int, offset int64, length int, prot int, flags int) (data []byte, errno int) {
+	if length <= 0 {
+		return nil, EINVAL
+	}
+
+	// Map the requested memory.
+	addr, errno := m.mmap(0, uintptr(length), prot, flags, fd, offset)
+	if errno != 0 {
+		return nil, errno
+	}
+
+	// Slice memory layout
+	var sl = struct {
+		addr uintptr
+		len  int
+		cap  int
+	}{addr, length, length}
+
+	// Use unsafe to turn sl into a []byte.
+	b := *(*[]byte)(unsafe.Pointer(&sl))
+
+	// Register mapping in m and return it.
+	p := &b[cap(b)-1]
+	m.Lock()
+	defer m.Unlock()
+	m.active[p] = b
+	return b, 0
+}
+
+func (m *mmapper) Munmap(data []byte) (errno int) {
+	if len(data) == 0 || len(data) != cap(data) {
+		return EINVAL
+	}
+
+	// Find the base of the mapping.
+	p := &data[cap(data)-1]
+	m.Lock()
+	defer m.Unlock()
+	b := m.active[p]
+	if b == nil || &b[0] != &data[0] {
+		return EINVAL
+	}
+
+	// Unmap the memory and update m.
+	if errno := m.munmap(uintptr(unsafe.Pointer(&b[0])), uintptr(len(b))); errno != 0 {
+		return errno
+	}
+	m.active[p] = nil, false
+	return 0
+}
+
+var mapper = &mmapper{
+	active: make(map[*byte][]byte),
+	mmap:   mmap,
+	munmap: munmap,
+}
+
+func Mmap(fd int, offset int64, length int, prot int, flags int) (data []byte, errno int) {
+	return mapper.Mmap(fd, offset, length, prot, flags)
+}
+
+func Munmap(b []byte) (errno int) {
+	return mapper.Munmap(b)
+}