build: require old Go to build new Go (and convert cmd/dist to Go)

This CL introduces the bootstrap requirement that in order to
build the current release (or development version) of Go, you
need an older Go release (1.4 or newer) already installed.
This requirement is the whole point of this CL.

To enforce the requirement, convert cmd/dist from C to Go.

With this bootstrapping out of the way, we can move on to
replacing other, larger C programs like the Go compiler,
the assemblers, and the linker.

See golang.org/s/go15bootstrap for details.

Change-Id: I53fd08ddacf3df9fae94fe2c986dba427ee4a21d
Reviewed-on: https://go-review.googlesource.com/2470
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Rob Pike <r@golang.org>

1 files changed, 49 insertions, 0 deletions

diff --git a/src/cmd/dist/sys_windows.go b/src/cmd/dist/sys_windows.go
new file mode 100644
index 0000000000..c6867fb895
--- /dev/null
+++ b/src/cmd/dist/sys_windows.go
@@ -0,0 +1,49 @@
+// Copyright 2015 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.
+
+package main
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+var (
+	modkernel32       = syscall.NewLazyDLL("kernel32.dll")
+	procGetSystemInfo = syscall.NewProc("GetSystemInfo")
+)
+
+// see http://msdn.microsoft.com/en-us/library/windows/desktop/ms724958(v=vs.85).aspx
+type systeminfo struct {
+	wProcessorArchitecture      uint16
+	wReserved                   uint16
+	dwPageSize                  uint32
+	lpMinimumApplicationAddress uintptr
+	lpMaximumApplicationAddress uintptr
+	dwActiveProcessorMask       uintptr
+	dwNumberOfProcessors        uint32
+	dwProcessorType             uint32
+	dwAllocationGranularity     uint32
+	wProcessorLevel             uint16
+	wProcessorRevision          uint16
+}
+
+const (
+	PROCESSOR_ARCHITECTURE_AMD64 = 9
+	PROCESSOR_ARCHITECTURE_INTEL = 0
+)
+
+var sysinfo systeminfo
+
+func sysinit() {
+	syscall.Syscall(procGetSystemInfo.Addr(), 1, uintptr(unsafe.Pointer(&sysinfo)), 0, 0)
+	switch sysinfo.wProcessorArchitecture {
+	case PROCESSOR_ARCHITECTURE_AMD64:
+		gohostarch = "amd64"
+	case PROCESSOR_ARCHITECTURE_INTEL:
+		gohostarch = "386"
+	default:
+		fatal("unknown processor architecture")
+	}
+}