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pkg/proc: remove callFrameRegs from stackIterator

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Since it's just a scratchpad to calculate the new set of registers it
makes more sense to have it as a local variable in Next and
advanceRegs.
This commit is contained in:
aarzilli 2017-11-17 19:29:24 +01:00 committed by Derek Parker
parent f4e2000fc8
commit 8d34bb5bb4
1 changed files with 10 additions and 11 deletions
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21
pkg/proc/stack.go
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@ -100,9 +100,8 @@ type stackIterator struct {
stackBarrierPC uint64
stkbar []savedLR
// regs is the register set for the next frame, callFrameRegs is the
// register set for the call frame of the next frame.
regs, callFrameRegs op.DwarfRegisters
// regs is the register set for the current frame
regs op.DwarfRegisters
}
type savedLR struct {
@ -138,7 +137,7 @@ func (it *stackIterator) Next() bool {
if it.err != nil || it.atend {
return false
}
ret, retaddr := it.advanceRegs()
callFrameRegs, ret, retaddr := it.advanceRegs()
it.frame = it.newStackframe(ret, retaddr)
if it.frame.Ret <= 0 {
@ -160,7 +159,7 @@ func (it *stackIterator) Next() bool {
it.top = false
it.pc = it.frame.Ret
it.regs = it.callFrameRegs
it.regs = callFrameRegs
return true
}
@ -221,7 +220,7 @@ func (it *stackIterator) stacktrace(depth int) ([]Stackframe, error) {
// advanceRegs calculates it.callFrameRegs using it.regs and the frame
// descriptor entry for the current stack frame.
// it.regs.CallFrameCFA is updated.
func (it *stackIterator) advanceRegs() (ret uint64, retaddr uint64) {
func (it *stackIterator) advanceRegs() (callFrameRegs op.DwarfRegisters, ret uint64, retaddr uint64) {
fde, err := it.bi.frameEntries.FDEForPC(it.pc)
var framectx *frame.FrameContext
if _, nofde := err.(*frame.NoFDEForPCError); nofde {
@ -233,11 +232,11 @@ func (it *stackIterator) advanceRegs() (ret uint64, retaddr uint64) {
cfareg, err := it.executeFrameRegRule(0, framectx.CFA, 0)
if cfareg == nil {
it.err = fmt.Errorf("CFA becomes undefined at PC %#x", it.pc)
return 0, 0
return op.DwarfRegisters{}, 0, 0
}
it.regs.CFA = int64(cfareg.Uint64Val)
it.callFrameRegs = op.DwarfRegisters{ByteOrder: it.regs.ByteOrder, PCRegNum: it.regs.PCRegNum, SPRegNum: it.regs.SPRegNum}
callFrameRegs = op.DwarfRegisters{ByteOrder: it.regs.ByteOrder, PCRegNum: it.regs.PCRegNum, SPRegNum: it.regs.SPRegNum}
// According to the standard the compiler should be responsible for emitting
// rules for the RSP register so that it can then be used to calculate CFA,
@ -246,11 +245,11 @@ func (it *stackIterator) advanceRegs() (ret uint64, retaddr uint64) {
// implicit.
// See also the comment in dwarf2_frame_default_init in
// $GDB_SOURCE/dwarf2-frame.c
it.callFrameRegs.AddReg(uint64(amd64DwarfSPRegNum), cfareg)
callFrameRegs.AddReg(uint64(amd64DwarfSPRegNum), cfareg)
for i, regRule := range framectx.Regs {
reg, err := it.executeFrameRegRule(i, regRule, it.regs.CFA)
it.callFrameRegs.AddReg(i, reg)
callFrameRegs.AddReg(i, reg)
if i == framectx.RetAddrReg {
if reg == nil {
if err == nil {
@ -264,7 +263,7 @@ func (it *stackIterator) advanceRegs() (ret uint64, retaddr uint64) {
}
}
return ret, retaddr
return callFrameRegs, ret, retaddr
}
func (it *stackIterator) executeFrameRegRule(regnum uint64, rule frame.DWRule, cfa int64) (*op.DwarfRegister, error) {