gcc/libgo/go/runtime/panic.go

91 lines
2.2 KiB
Go

// Copyright 2014 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
// Calling panic with one of the errors below will call errorString.Error
// which will call mallocgc to concatenate strings. That will fail if
// malloc is locked, causing a confusing error message. Throw a better
// error message instead.
func panicCheckMalloc(err error) {
gp := getg()
if gp != nil && gp.m != nil && gp.m.mallocing != 0 {
throw(string(err.(errorString)))
}
}
var indexError = error(errorString("index out of range"))
func panicindex() {
panicCheckMalloc(indexError)
panic(indexError)
}
var sliceError = error(errorString("slice bounds out of range"))
func panicslice() {
panicCheckMalloc(sliceError)
panic(sliceError)
}
var divideError = error(errorString("integer divide by zero"))
func panicdivide() {
panicCheckMalloc(divideError)
panic(divideError)
}
var overflowError = error(errorString("integer overflow"))
func panicoverflow() {
panicCheckMalloc(overflowError)
panic(overflowError)
}
var floatError = error(errorString("floating point error"))
func panicfloat() {
panicCheckMalloc(floatError)
panic(floatError)
}
var memoryError = error(errorString("invalid memory address or nil pointer dereference"))
func panicmem() {
panicCheckMalloc(memoryError)
panic(memoryError)
}
func throwreturn() {
throw("no return at end of a typed function - compiler is broken")
}
func throwinit() {
throw("recursive call during initialization - linker skew")
}
//go:nosplit
func canpanic(gp *g) bool {
// Note that g is m->gsignal, different from gp.
// Note also that g->m can change at preemption, so m can go stale
// if this function ever makes a function call.
_g_ := getg()
_m_ := _g_.m
// Is it okay for gp to panic instead of crashing the program?
// Yes, as long as it is running Go code, not runtime code,
// and not stuck in a system call.
if gp == nil || gp != _m_.curg {
return false
}
if _m_.locks-_m_.softfloat != 0 || _m_.mallocing != 0 || _m_.throwing != 0 || _m_.preemptoff != "" || _m_.dying != 0 {
return false
}
status := readgstatus(gp)
if status&^_Gscan != _Grunning || gp.syscallsp != 0 {
return false
}
return true
}