[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://golang.org/cl/168500044

1 files changed, 46 insertions, 0 deletions

diff --git a/src/runtime/signal_linux_amd64.go b/src/runtime/signal_linux_amd64.go
new file mode 100644
index 0000000000..d94b191024
--- /dev/null
+++ b/src/runtime/signal_linux_amd64.go
@@ -0,0 +1,46 @@
+// 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 (*sigcontext)(unsafe.Pointer(&(*ucontext)(c.ctxt).uc_mcontext))
+}
+func (c *sigctxt) rax() uint64     { return c.regs().rax }
+func (c *sigctxt) rbx() uint64     { return c.regs().rbx }
+func (c *sigctxt) rcx() uint64     { return c.regs().rcx }
+func (c *sigctxt) rdx() uint64     { return c.regs().rdx }
+func (c *sigctxt) rdi() uint64     { return c.regs().rdi }
+func (c *sigctxt) rsi() uint64     { return c.regs().rsi }
+func (c *sigctxt) rbp() uint64     { return c.regs().rbp }
+func (c *sigctxt) rsp() uint64     { return c.regs().rsp }
+func (c *sigctxt) r8() uint64      { return c.regs().r8 }
+func (c *sigctxt) r9() uint64      { return c.regs().r9 }
+func (c *sigctxt) r10() uint64     { return c.regs().r10 }
+func (c *sigctxt) r11() uint64     { return c.regs().r11 }
+func (c *sigctxt) r12() uint64     { return c.regs().r12 }
+func (c *sigctxt) r13() uint64     { return c.regs().r13 }
+func (c *sigctxt) r14() uint64     { return c.regs().r14 }
+func (c *sigctxt) r15() uint64     { return c.regs().r15 }
+func (c *sigctxt) rip() uint64     { return c.regs().rip }
+func (c *sigctxt) rflags() uint64  { return c.regs().eflags }
+func (c *sigctxt) cs() uint64      { return uint64(c.regs().cs) }
+func (c *sigctxt) fs() uint64      { return uint64(c.regs().fs) }
+func (c *sigctxt) gs() uint64      { return uint64(c.regs().gs) }
+func (c *sigctxt) sigcode() uint64 { return uint64(c.info.si_code) }
+func (c *sigctxt) sigaddr() uint64 { return uint64(*(*uintptr)(add(unsafe.Pointer(c.info), 2*ptrSize))) }
+
+func (c *sigctxt) set_rip(x uint64)     { c.regs().rip = x }
+func (c *sigctxt) set_rsp(x uint64)     { c.regs().rsp = x }
+func (c *sigctxt) set_sigcode(x uint64) { c.info.si_code = int32(x) }
+func (c *sigctxt) set_sigaddr(x uint64) {
+	*(*uintptr)(add(unsafe.Pointer(c.info), 2*ptrSize)) = uintptr(x)
+}