[dev.cc] runtime: convert signal handlers from C to Go

This code overused macros and could not be
converted automatically. Instead a new sigctxt
type had to be defined for each os/arch combination,
with a common (implicit) interface used by the
arch-specific signal handler code.

[This CL is part of the removal of C code from package runtime.
See golang.org/s/dev.cc for an overview.]

LGTM=r
R=r
CC=austin, dvyukov, golang-codereviews, iant, khr
https://codereview.appspot.com/168500044

1 files changed, 36 insertions, 0 deletions

diff --git a/src/runtime/signal_linux_386.go b/src/runtime/signal_linux_386.go
new file mode 100644
index 000000000..41eae80ea
--- /dev/null
+++ b/src/runtime/signal_linux_386.go
@@ -0,0 +1,36 @@
+// Copyright 2013 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 runtime
+
+import "unsafe"
+
+type sigctxt struct {
+	info *siginfo
+	ctxt unsafe.Pointer
+}
+
+func (c *sigctxt) regs() *sigcontext { return &(*ucontext)(c.ctxt).uc_mcontext }
+func (c *sigctxt) eax() uint32       { return c.regs().eax }
+func (c *sigctxt) ebx() uint32       { return c.regs().ebx }
+func (c *sigctxt) ecx() uint32       { return c.regs().ecx }
+func (c *sigctxt) edx() uint32       { return c.regs().edx }
+func (c *sigctxt) edi() uint32       { return c.regs().edi }
+func (c *sigctxt) esi() uint32       { return c.regs().esi }
+func (c *sigctxt) ebp() uint32       { return c.regs().ebp }
+func (c *sigctxt) esp() uint32       { return c.regs().esp }
+func (c *sigctxt) eip() uint32       { return c.regs().eip }
+func (c *sigctxt) eflags() uint32    { return c.regs().eflags }
+func (c *sigctxt) cs() uint32        { return uint32(c.regs().cs) }
+func (c *sigctxt) fs() uint32        { return uint32(c.regs().fs) }
+func (c *sigctxt) gs() uint32        { return uint32(c.regs().gs) }
+func (c *sigctxt) sigcode() uint32   { return uint32(c.info.si_code) }
+func (c *sigctxt) sigaddr() uint32   { return uint32(*(*uintptr)(add(unsafe.Pointer(c.info), 2*ptrSize))) }
+
+func (c *sigctxt) set_eip(x uint32)     { c.regs().eip = x }
+func (c *sigctxt) set_esp(x uint32)     { c.regs().esp = x }
+func (c *sigctxt) set_sigcode(x uint32) { c.info.si_code = int32(x) }
+func (c *sigctxt) set_sigaddr(x uint32) {
+	*(*uintptr)(add(unsafe.Pointer(c.info), 2*ptrSize)) = uintptr(x)
+}