github.com/liujq9674git/golang-src-1.7@v0.0.0-20230517174348-17f6ec47f3f8/src/runtime/signal_darwin_arm.go (about)

     1  // Copyright 2014 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package runtime
     6  
     7  import "unsafe"
     8  
     9  type sigctxt struct {
    10  	info *siginfo
    11  	ctxt unsafe.Pointer
    12  }
    13  
    14  func (c *sigctxt) regs() *regs32   { return &(*ucontext)(c.ctxt).uc_mcontext.ss }
    15  func (c *sigctxt) r0() uint32      { return c.regs().r[0] }
    16  func (c *sigctxt) r1() uint32      { return c.regs().r[1] }
    17  func (c *sigctxt) r2() uint32      { return c.regs().r[2] }
    18  func (c *sigctxt) r3() uint32      { return c.regs().r[3] }
    19  func (c *sigctxt) r4() uint32      { return c.regs().r[4] }
    20  func (c *sigctxt) r5() uint32      { return c.regs().r[5] }
    21  func (c *sigctxt) r6() uint32      { return c.regs().r[6] }
    22  func (c *sigctxt) r7() uint32      { return c.regs().r[7] }
    23  func (c *sigctxt) r8() uint32      { return c.regs().r[8] }
    24  func (c *sigctxt) r9() uint32      { return c.regs().r[9] }
    25  func (c *sigctxt) r10() uint32     { return c.regs().r[10] }
    26  func (c *sigctxt) fp() uint32      { return c.regs().r[11] }
    27  func (c *sigctxt) ip() uint32      { return c.regs().r[12] }
    28  func (c *sigctxt) sp() uint32      { return c.regs().sp }
    29  func (c *sigctxt) lr() uint32      { return c.regs().lr }
    30  func (c *sigctxt) pc() uint32      { return c.regs().pc }
    31  func (c *sigctxt) cpsr() uint32    { return c.regs().cpsr }
    32  func (c *sigctxt) fault() uint32   { return c.info.si_addr }
    33  func (c *sigctxt) sigcode() uint32 { return uint32(c.info.si_code) }
    34  func (c *sigctxt) trap() uint32    { return 0 }
    35  func (c *sigctxt) error() uint32   { return 0 }
    36  func (c *sigctxt) oldmask() uint32 { return 0 }
    37  
    38  func (c *sigctxt) set_pc(x uint32)  { c.regs().pc = x }
    39  func (c *sigctxt) set_sp(x uint32)  { c.regs().sp = x }
    40  func (c *sigctxt) set_lr(x uint32)  { c.regs().lr = x }
    41  func (c *sigctxt) set_r10(x uint32) { c.regs().r[10] = x }
    42  
    43  func (c *sigctxt) set_sigcode(x uint32) { c.info.si_code = int32(x) }
    44  func (c *sigctxt) set_sigaddr(x uint32) { c.info.si_addr = x }
    45  
    46  func (c *sigctxt) fixsigcode(sig uint32) {
    47  	switch sig {
    48  	case _SIGTRAP:
    49  		// OS X sets c.sigcode() == TRAP_BRKPT unconditionally for all SIGTRAPs,
    50  		// leaving no way to distinguish a breakpoint-induced SIGTRAP
    51  		// from an asynchronous signal SIGTRAP.
    52  		// They all look breakpoint-induced by default.
    53  		// Try looking at the code to see if it's a breakpoint.
    54  		// The assumption is that we're very unlikely to get an
    55  		// asynchronous SIGTRAP at just the moment that the
    56  		// PC started to point at unmapped memory.
    57  		pc := uintptr(c.pc())
    58  		// OS X will leave the pc just after the instruction.
    59  		code := (*uint32)(unsafe.Pointer(pc - 4))
    60  		if *code != 0xe7f001f0 {
    61  			// SIGTRAP on something other than breakpoint.
    62  			c.set_sigcode(_SI_USER)
    63  		}
    64  	}
    65  }