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runtime: refactor test for pushing sigpanic frame

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This logic is duplicated in all of the preparePanic functions. Pull it
out into one architecture-independent function.

Change-Id: I7ef4e78e3eda0b7be1a480fb5245fc7424fb2b4e
Reviewed-on: https://go-review.googlesource.com/91255
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This commit is contained in:
Austin Clements 2018-01-31 17:34:22 -05:00
parent b1679e4d03
commit 615d44c287
9 changed files with 49 additions and 102 deletions
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33
src/runtime/panic.go
View File

@ -786,3 +786,36 @@ func canpanic(gp *g) bool {
}
return true
}
// shouldPushSigpanic returns true if pc should be used as sigpanic's
// return PC (pushing a frame for the call). Otherwise, it should be
// left alone so that LR is used as sigpanic's return PC, effectively
// replacing the top-most frame with sigpanic. This is used by
// preparePanic.
func shouldPushSigpanic(gp *g, pc, lr uintptr) bool {
if pc == 0 {
// Probably a call to a nil func. The old LR is more
// useful in the stack trace. Not pushing the frame
// will make the trace look like a call to sigpanic
// instead. (Otherwise the trace will end at sigpanic
// and we won't get to see who faulted.)
return false
}
// If we don't recognize the PC as code, but we do recognize
// the link register as code, then this assumes the panic was
// caused by a call to non-code. In this case, we want to
// ignore this call to make unwinding show the context.
if findfunc(pc).valid() {
// This wasn't a bad call, so use PC as sigpanic's
// return PC.
return true
}
if findfunc(lr).valid() {
// This was a bad call, but the LR is good, so use the
// LR as sigpanic's return PC.
return false
}
// Neither the PC or LR is good. Hopefully pushing a frame
// will work.
return true
}

17
src/runtime/signal_386.go
View File

@ -56,21 +56,8 @@ func (c *sigctxt) preparePanic(sig uint32, gp *g) {
pc := uintptr(c.eip())
sp := uintptr(c.esp())
// If we don't recognize the PC as code
// but we do recognize the top pointer on the stack as code,
// then assume this was a call to non-code and treat like
// pc == 0, to make unwinding show the context.
if pc != 0 && !findfunc(pc).valid() && findfunc(*(*uintptr)(unsafe.Pointer(sp))).valid() {
pc = 0
}
// Only push runtime.sigpanic if pc != 0.
// If pc == 0, probably panicked because of a
// call to a nil func. Not pushing that onto sp will
// make the trace look like a call to runtime.sigpanic instead.
// (Otherwise the trace will end at runtime.sigpanic and we
// won't get to see who faulted.)
if pc != 0 {
if shouldPushSigpanic(gp, pc, *(*uintptr)(unsafe.Pointer(sp))) {
// Make it look like the faulting PC called sigpanic.
if sys.RegSize > sys.PtrSize {
sp -= sys.PtrSize
*(*uintptr)(unsafe.Pointer(sp)) = 0

17
src/runtime/signal_amd64x.go
View File

@ -67,21 +67,8 @@ func (c *sigctxt) preparePanic(sig uint32, gp *g) {
pc := uintptr(c.rip())
sp := uintptr(c.rsp())
// If we don't recognize the PC as code
// but we do recognize the top pointer on the stack as code,
// then assume this was a call to non-code and treat like
// pc == 0, to make unwinding show the context.
if pc != 0 && !findfunc(pc).valid() && findfunc(*(*uintptr)(unsafe.Pointer(sp))).valid() {
pc = 0
}
// Only push runtime.sigpanic if pc != 0.
// If pc == 0, probably panicked because of a
// call to a nil func. Not pushing that onto sp will
// make the trace look like a call to runtime.sigpanic instead.
// (Otherwise the trace will end at runtime.sigpanic and we
// won't get to see who faulted.)
if pc != 0 {
if shouldPushSigpanic(gp, pc, *(*uintptr)(unsafe.Pointer(sp))) {
// Make it look the like faulting PC called sigpanic.
if sys.RegSize > sys.PtrSize {
sp -= sys.PtrSize
*(*uintptr)(unsafe.Pointer(sp)) = 0

14
src/runtime/signal_arm.go
View File

@ -53,18 +53,8 @@ func (c *sigctxt) preparePanic(sig uint32, gp *g) {
pc := gp.sigpc
// If we don't recognize the PC as code
// but we do recognize the link register as code,
// then assume this was a call to non-code and treat like
// pc == 0, to make unwinding show the context.
if pc != 0 && !findfunc(pc).valid() && findfunc(uintptr(c.lr())).valid() {
pc = 0
}
// Don't bother saving PC if it's zero, which is
// probably a call to a nil func: the old link register
// is more useful in the stack trace.
if pc != 0 {
if shouldPushSigpanic(gp, pc, uintptr(c.lr())) {
// Make it look the like faulting PC called sigpanic.
c.set_lr(uint32(pc))
}

14
src/runtime/signal_arm64.go
View File

@ -69,18 +69,8 @@ func (c *sigctxt) preparePanic(sig uint32, gp *g) {
pc := gp.sigpc
// If we don't recognize the PC as code
// but we do recognize the link register as code,
// then assume this was a call to non-code and treat like
// pc == 0, to make unwinding show the context.
if pc != 0 && !findfunc(pc).valid() && findfunc(uintptr(c.lr())).valid() {
pc = 0
}
// Don't bother saving PC if it's zero, which is
// probably a call to a nil func: the old link register
// is more useful in the stack trace.
if pc != 0 {
if shouldPushSigpanic(gp, pc, uintptr(c.lr())) {
// Make it look the like faulting PC called sigpanic.
c.set_lr(uint64(pc))
}

14
src/runtime/signal_linux_s390x.go
View File

@ -99,18 +99,8 @@ func (c *sigctxt) preparePanic(sig uint32, gp *g) {
pc := uintptr(gp.sigpc)
// If we don't recognize the PC as code
// but we do recognize the link register as code,
// then assume this was a call to non-code and treat like
// pc == 0, to make unwinding show the context.
if pc != 0 && !findfunc(pc).valid() && findfunc(uintptr(c.link())).valid() {
pc = 0
}
// Don't bother saving PC if it's zero, which is
// probably a call to a nil func: the old link register
// is more useful in the stack trace.
if pc != 0 {
if shouldPushSigpanic(gp, pc, uintptr(c.link())) {
// Make it look the like faulting PC called sigpanic.
c.set_link(uint64(pc))
}

14
src/runtime/signal_mips64x.go
View File

@ -73,18 +73,8 @@ func (c *sigctxt) preparePanic(sig uint32, gp *g) {
pc := gp.sigpc
// If we don't recognize the PC as code
// but we do recognize the link register as code,
// then assume this was a call to non-code and treat like
// pc == 0, to make unwinding show the context.
if pc != 0 && !findfunc(pc).valid() && findfunc(uintptr(c.link())).valid() {
pc = 0
}
// Don't bother saving PC if it's zero, which is
// probably a call to a nil func: the old link register
// is more useful in the stack trace.
if pc != 0 {
if shouldPushSigpanic(gp, pc, uintptr(c.link())) {
// Make it look the like faulting PC called sigpanic.
c.set_link(uint64(pc))
}

14
src/runtime/signal_mipsx.go
View File

@ -70,18 +70,8 @@ func (c *sigctxt) preparePanic(sig uint32, gp *g) {
pc := gp.sigpc
// If we don't recognize the PC as code
// but we do recognize the link register as code,
// then assume this was a call to non-code and treat like
// pc == 0, to make unwinding show the context.
if pc != 0 && !findfunc(pc).valid() && findfunc(uintptr(c.link())).valid() {
pc = 0
}
// Don't bother saving PC if it's zero, which is
// probably a call to a nil func: the old link register
// is more useful in the stack trace.
if pc != 0 {
if shouldPushSigpanic(gp, pc, uintptr(c.link())) {
// Make it look the like faulting PC called sigpanic.
c.set_link(uint32(pc))
}

14
src/runtime/signal_ppc64x.go
View File

@ -74,18 +74,8 @@ func (c *sigctxt) preparePanic(sig uint32, gp *g) {
pc := gp.sigpc
// If we don't recognize the PC as code
// but we do recognize the link register as code,
// then assume this was a call to non-code and treat like
// pc == 0, to make unwinding show the context.
if pc != 0 && !findfunc(pc).valid() && findfunc(uintptr(c.link())).valid() {
pc = 0
}
// Don't bother saving PC if it's zero, which is
// probably a call to a nil func: the old link register
// is more useful in the stack trace.
if pc != 0 {
if shouldPushSigpanic(gp, pc, uintptr(c.link())) {
// Make it look the like faulting PC called sigpanic.
c.set_link(uint64(pc))
}