5b4f4a81b1
The stacktrace code occasionally needs the value of g.m.g0.sched.sp to switch stacks. Since this is only needed rarely and calling parseG is relatively expensive we should delay doing it until we know it will be needed. Benchmark before: BenchmarkConditionalBreakpoints-4 1 17326345671 ns/op Benchmark after: BenchmarkConditionalBreakpoints-4 1 15649407130 ns/op Reduces conditional breakpoint latency from 1.7ms to 1.56ms. Updates #1549
454 lines
14 KiB
Go
454 lines
14 KiB
Go
package proc
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import (
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"bytes"
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"encoding/binary"
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"fmt"
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"os"
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"strings"
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"github.com/go-delve/delve/pkg/dwarf/frame"
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"github.com/go-delve/delve/pkg/dwarf/op"
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"golang.org/x/arch/arm64/arm64asm"
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)
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// ARM64 represents the ARM64 CPU architecture.
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type ARM64 struct {
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gStructOffset uint64
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goos string
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// crosscall2fn is the DIE of crosscall2, a function used by the go runtime
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// to call C functions. This function in go 1.9 (and previous versions) had
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// a bad frame descriptor which needs to be fixed to generate good stack
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// traces.
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crosscall2fn *Function
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// sigreturnfn is the DIE of runtime.sigreturn, the return trampoline for
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// the signal handler. See comment in FixFrameUnwindContext for a
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// description of why this is needed.
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sigreturnfn *Function
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}
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const (
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arm64DwarfIPRegNum uint64 = 32
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arm64DwarfSPRegNum uint64 = 31
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arm64DwarfLRRegNum uint64 = 30
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arm64DwarfBPRegNum uint64 = 29
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)
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var arm64BreakInstruction = []byte{0x0, 0x0, 0x20, 0xd4}
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// ARM64Arch returns an initialized ARM64
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// struct.
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func ARM64Arch(goos string) *ARM64 {
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return &ARM64{
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goos: goos,
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}
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}
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// PtrSize returns the size of a pointer
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// on this architecture.
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func (a *ARM64) PtrSize() int {
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return 8
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}
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// MaxInstructionLength returns the maximum lenght of an instruction.
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func (a *ARM64) MaxInstructionLength() int {
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return 4
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}
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// BreakpointInstruction returns the Breakpoint
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// instruction for this architecture.
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func (a *ARM64) BreakpointInstruction() []byte {
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return arm64BreakInstruction
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}
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// BreakInstrMovesPC returns whether the
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// breakpoint instruction will change the value
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// of PC after being executed
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func (a *ARM64) BreakInstrMovesPC() bool {
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return false
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}
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// BreakpointSize returns the size of the
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// breakpoint instruction on this architecture.
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func (a *ARM64) BreakpointSize() int {
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return len(arm64BreakInstruction)
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}
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// Always return false for now.
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func (a *ARM64) DerefTLS() bool {
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return false
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}
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// FixFrameUnwindContext adds default architecture rules to fctxt or returns
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// the default frame unwind context if fctxt is nil.
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func (a *ARM64) FixFrameUnwindContext(fctxt *frame.FrameContext, pc uint64, bi *BinaryInfo) *frame.FrameContext {
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if a.sigreturnfn == nil {
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a.sigreturnfn = bi.LookupFunc["runtime.sigreturn"]
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}
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if fctxt == nil || (a.sigreturnfn != nil && pc >= a.sigreturnfn.Entry && pc < a.sigreturnfn.End) {
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// When there's no frame descriptor entry use BP (the frame pointer) instead
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// - return register is [bp + a.PtrSize()] (i.e. [cfa-a.PtrSize()])
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// - cfa is bp + a.PtrSize()*2
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// - bp is [bp] (i.e. [cfa-a.PtrSize()*2])
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// - sp is cfa
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// When the signal handler runs it will move the execution to the signal
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// handling stack (installed using the sigaltstack system call).
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// This isn't a proper stack switch: the pointer to g in TLS will still
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// refer to whatever g was executing on that thread before the signal was
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// received.
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// Since go did not execute a stack switch the previous value of sp, pc
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// and bp is not saved inside g.sched, as it normally would.
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// The only way to recover is to either read sp/pc from the signal context
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// parameter (the ucontext_t* parameter) or to unconditionally follow the
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// frame pointer when we get to runtime.sigreturn (which is what we do
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// here).
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return &frame.FrameContext{
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RetAddrReg: arm64DwarfIPRegNum,
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Regs: map[uint64]frame.DWRule{
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arm64DwarfIPRegNum: frame.DWRule{
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Rule: frame.RuleOffset,
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Offset: int64(-a.PtrSize()),
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},
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arm64DwarfBPRegNum: frame.DWRule{
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Rule: frame.RuleOffset,
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Offset: int64(-2 * a.PtrSize()),
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},
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arm64DwarfSPRegNum: frame.DWRule{
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Rule: frame.RuleValOffset,
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Offset: 0,
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},
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},
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CFA: frame.DWRule{
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Rule: frame.RuleCFA,
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Reg: arm64DwarfBPRegNum,
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Offset: int64(2 * a.PtrSize()),
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},
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}
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}
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if a.crosscall2fn == nil {
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a.crosscall2fn = bi.LookupFunc["crosscall2"]
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}
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if a.crosscall2fn != nil && pc >= a.crosscall2fn.Entry && pc < a.crosscall2fn.End {
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rule := fctxt.CFA
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if rule.Offset == crosscall2SPOffsetBad {
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switch a.goos {
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case "windows":
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rule.Offset += crosscall2SPOffsetWindows
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default:
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rule.Offset += crosscall2SPOffsetNonWindows
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}
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}
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fctxt.CFA = rule
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}
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// We assume that RBP is the frame pointer and we want to keep it updated,
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// so that we can use it to unwind the stack even when we encounter frames
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// without descriptor entries.
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// If there isn't a rule already we emit one.
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if fctxt.Regs[arm64DwarfBPRegNum].Rule == frame.RuleUndefined {
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fctxt.Regs[arm64DwarfBPRegNum] = frame.DWRule{
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Rule: frame.RuleFramePointer,
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Reg: arm64DwarfBPRegNum,
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Offset: 0,
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}
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}
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if fctxt.Regs[arm64DwarfLRRegNum].Rule == frame.RuleUndefined {
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fctxt.Regs[arm64DwarfLRRegNum] = frame.DWRule{
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Rule: frame.RuleFramePointer,
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Reg: arm64DwarfLRRegNum,
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Offset: 0,
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}
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}
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return fctxt
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}
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const arm64cgocallSPOffsetSaveSlot = 0x8
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const prevG0schedSPOffsetSaveSlot = 0x10
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const spAlign = 16
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func (a *ARM64) SwitchStack(it *stackIterator, callFrameRegs *op.DwarfRegisters) bool {
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if it.frame.Current.Fn != nil {
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switch it.frame.Current.Fn.Name {
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case "runtime.asmcgocall", "runtime.cgocallback_gofunc", "runtime.sigpanic":
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//do nothing
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case "runtime.goexit", "runtime.rt0_go", "runtime.mcall":
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// Look for "top of stack" functions.
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it.atend = true
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return true
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case "crosscall2":
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//The offsets get from runtime/cgo/asm_arm64.s:10
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newsp, _ := readUintRaw(it.mem, uintptr(it.regs.SP()+8*24), int64(it.bi.Arch.PtrSize()))
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newbp, _ := readUintRaw(it.mem, uintptr(it.regs.SP()+8*14), int64(it.bi.Arch.PtrSize()))
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newlr, _ := readUintRaw(it.mem, uintptr(it.regs.SP()+8*15), int64(it.bi.Arch.PtrSize()))
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if it.regs.Reg(it.regs.BPRegNum) != nil {
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it.regs.Reg(it.regs.BPRegNum).Uint64Val = uint64(newbp)
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} else {
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reg, _ := it.readRegisterAt(it.regs.BPRegNum, it.regs.SP()+8*14)
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it.regs.AddReg(it.regs.BPRegNum, reg)
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}
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it.regs.Reg(it.regs.LRRegNum).Uint64Val = uint64(newlr)
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it.regs.Reg(it.regs.SPRegNum).Uint64Val = uint64(newsp)
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it.pc = newlr
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return true
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default:
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if it.systemstack && it.top && it.g != nil && strings.HasPrefix(it.frame.Current.Fn.Name, "runtime.") && it.frame.Current.Fn.Name != "runtime.fatalthrow" {
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// The runtime switches to the system stack in multiple places.
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// This usually happens through a call to runtime.systemstack but there
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// are functions that switch to the system stack manually (for example
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// runtime.morestack).
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// Since we are only interested in printing the system stack for cgo
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// calls we switch directly to the goroutine stack if we detect that the
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// function at the top of the stack is a runtime function.
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it.switchToGoroutineStack()
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return true
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}
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}
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}
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_, _, fn := it.bi.PCToLine(it.frame.Ret)
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if fn == nil {
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return false
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}
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switch fn.Name {
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case "runtime.asmcgocall":
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if !it.systemstack {
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return false
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}
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// This function is called by a goroutine to execute a C function and
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// switches from the goroutine stack to the system stack.
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// Since we are unwinding the stack from callee to caller we have to switch
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// from the system stack to the goroutine stack.
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off, _ := readIntRaw(it.mem, uintptr(callFrameRegs.SP()+arm64cgocallSPOffsetSaveSlot), int64(it.bi.Arch.PtrSize()))
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oldsp := callFrameRegs.SP()
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newsp := uint64(int64(it.stackhi) - off)
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// runtime.asmcgocall can also be called from inside the system stack,
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// in that case no stack switch actually happens
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if newsp == oldsp {
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return false
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}
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it.systemstack = false
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callFrameRegs.Reg(callFrameRegs.SPRegNum).Uint64Val = uint64(int64(newsp))
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return false
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case "runtime.cgocallback_gofunc":
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// For a detailed description of how this works read the long comment at
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// the start of $GOROOT/src/runtime/cgocall.go and the source code of
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// runtime.cgocallback_gofunc in $GOROOT/src/runtime/asm_arm64.s
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//
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// When a C functions calls back into go it will eventually call into
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// runtime.cgocallback_gofunc which is the function that does the stack
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// switch from the system stack back into the goroutine stack
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// Since we are going backwards on the stack here we see the transition
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// as goroutine stack -> system stack.
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if it.systemstack {
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return false
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}
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it.loadG0SchedSP()
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if it.g0_sched_sp <= 0 {
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return false
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}
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// entering the system stack
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callFrameRegs.Reg(callFrameRegs.SPRegNum).Uint64Val = it.g0_sched_sp
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// reads the previous value of g0.sched.sp that runtime.cgocallback_gofunc saved on the stack
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it.g0_sched_sp, _ = readUintRaw(it.mem, uintptr(callFrameRegs.SP()+prevG0schedSPOffsetSaveSlot), int64(it.bi.Arch.PtrSize()))
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it.systemstack = true
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return false
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}
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return false
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}
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func (a *ARM64) RegSize(regnum uint64) int {
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// fp registers
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if regnum >= 64 && regnum <= 95 {
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return 16
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}
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return 8 // general registers
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}
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// The mapping between hardware registers and DWARF registers is specified
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// in the DWARF for the ARM® Architecture page 7,
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// Table 1
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// http://infocenter.arm.com/help/topic/com.arm.doc.ihi0040b/IHI0040B_aadwarf.pdf
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var arm64DwarfToHardware = map[int]arm64asm.Reg{
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0: arm64asm.X0,
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1: arm64asm.X1,
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2: arm64asm.X2,
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3: arm64asm.X3,
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4: arm64asm.X4,
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5: arm64asm.X5,
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6: arm64asm.X6,
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7: arm64asm.X7,
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8: arm64asm.X8,
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9: arm64asm.X9,
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10: arm64asm.X10,
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11: arm64asm.X11,
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12: arm64asm.X12,
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13: arm64asm.X13,
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14: arm64asm.X14,
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15: arm64asm.X15,
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16: arm64asm.X16,
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17: arm64asm.X17,
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18: arm64asm.X18,
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19: arm64asm.X19,
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20: arm64asm.X20,
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21: arm64asm.X21,
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22: arm64asm.X22,
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23: arm64asm.X23,
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24: arm64asm.X24,
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25: arm64asm.X25,
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26: arm64asm.X26,
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27: arm64asm.X27,
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28: arm64asm.X28,
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29: arm64asm.X29,
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30: arm64asm.X30,
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31: arm64asm.SP,
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64: arm64asm.V0,
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65: arm64asm.V1,
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66: arm64asm.V2,
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67: arm64asm.V3,
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68: arm64asm.V4,
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69: arm64asm.V5,
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70: arm64asm.V6,
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71: arm64asm.V7,
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72: arm64asm.V8,
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73: arm64asm.V9,
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74: arm64asm.V10,
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75: arm64asm.V11,
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76: arm64asm.V12,
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77: arm64asm.V13,
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78: arm64asm.V14,
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79: arm64asm.V15,
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80: arm64asm.V16,
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81: arm64asm.V17,
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82: arm64asm.V18,
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83: arm64asm.V19,
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84: arm64asm.V20,
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85: arm64asm.V21,
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86: arm64asm.V22,
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87: arm64asm.V23,
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88: arm64asm.V24,
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89: arm64asm.V25,
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90: arm64asm.V26,
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91: arm64asm.V27,
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92: arm64asm.V28,
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93: arm64asm.V29,
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94: arm64asm.V30,
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95: arm64asm.V31,
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}
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func maxArm64DwarfRegister() int {
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max := int(arm64DwarfIPRegNum)
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for i := range arm64DwarfToHardware {
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if i > max {
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max = i
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}
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}
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return max
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}
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// RegistersToDwarfRegisters converts hardware registers to the format used
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// by the DWARF expression interpreter.
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func (a *ARM64) RegistersToDwarfRegisters(staticBase uint64, regs Registers) op.DwarfRegisters {
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dregs := make([]*op.DwarfRegister, maxArm64DwarfRegister()+1)
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dregs[arm64DwarfIPRegNum] = op.DwarfRegisterFromUint64(regs.PC())
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dregs[arm64DwarfSPRegNum] = op.DwarfRegisterFromUint64(regs.SP())
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dregs[arm64DwarfBPRegNum] = op.DwarfRegisterFromUint64(regs.BP())
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if lr, err := regs.Get(int(arm64asm.X30)); err != nil {
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dregs[arm64DwarfLRRegNum] = op.DwarfRegisterFromUint64(lr)
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}
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for dwarfReg, asmReg := range arm64DwarfToHardware {
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v, err := regs.Get(int(asmReg))
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if err == nil {
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dregs[dwarfReg] = op.DwarfRegisterFromUint64(v)
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}
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}
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return op.DwarfRegisters{
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StaticBase: staticBase,
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Regs: dregs,
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ByteOrder: binary.LittleEndian,
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PCRegNum: arm64DwarfIPRegNum,
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SPRegNum: arm64DwarfSPRegNum,
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BPRegNum: arm64DwarfBPRegNum,
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LRRegNum: arm64DwarfLRRegNum,
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}
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}
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// AddrAndStackRegsToDwarfRegisters returns DWARF registers from the passed in
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// PC, SP, and BP registers in the format used by the DWARF expression interpreter.
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func (a *ARM64) AddrAndStackRegsToDwarfRegisters(staticBase, pc, sp, bp, lr uint64) op.DwarfRegisters {
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dregs := make([]*op.DwarfRegister, arm64DwarfIPRegNum+1)
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dregs[arm64DwarfIPRegNum] = op.DwarfRegisterFromUint64(pc)
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dregs[arm64DwarfSPRegNum] = op.DwarfRegisterFromUint64(sp)
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dregs[arm64DwarfBPRegNum] = op.DwarfRegisterFromUint64(bp)
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dregs[arm64DwarfLRRegNum] = op.DwarfRegisterFromUint64(lr)
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return op.DwarfRegisters{
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StaticBase: staticBase,
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Regs: dregs,
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ByteOrder: binary.LittleEndian,
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PCRegNum: arm64DwarfIPRegNum,
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SPRegNum: arm64DwarfSPRegNum,
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BPRegNum: arm64DwarfBPRegNum,
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LRRegNum: arm64DwarfLRRegNum,
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}
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}
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func (a *ARM64) DwarfRegisterToString(name string, reg *op.DwarfRegister) string {
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if reg.Bytes != nil && (name[0] == 'v' || name[0] == 'V') {
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buf := bytes.NewReader(reg.Bytes)
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var out bytes.Buffer
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var vi [16]uint8
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for i := range vi {
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binary.Read(buf, binary.LittleEndian, &vi[i])
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}
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fmt.Fprintf(&out, "0x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x", vi[15], vi[14], vi[13], vi[12], vi[11], vi[10], vi[9], vi[8], vi[7], vi[6], vi[5], vi[4], vi[3], vi[2], vi[1], vi[0])
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fmt.Fprintf(&out, "\tv2_int={ %02x%02x%02x%02x%02x%02x%02x%02x %02x%02x%02x%02x%02x%02x%02x%02x }", vi[7], vi[6], vi[5], vi[4], vi[3], vi[2], vi[1], vi[0], vi[15], vi[14], vi[13], vi[12], vi[11], vi[10], vi[9], vi[8])
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fmt.Fprintf(&out, "\tv4_int={ %02x%02x%02x%02x %02x%02x%02x%02x %02x%02x%02x%02x %02x%02x%02x%02x }", vi[3], vi[2], vi[1], vi[0], vi[7], vi[6], vi[5], vi[4], vi[11], vi[10], vi[9], vi[8], vi[15], vi[14], vi[13], vi[12])
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fmt.Fprintf(&out, "\tv8_int={ %02x%02x %02x%02x %02x%02x %02x%02x %02x%02x %02x%02x %02x%02x %02x%02x }", vi[1], vi[0], vi[3], vi[2], vi[5], vi[4], vi[7], vi[6], vi[9], vi[8], vi[11], vi[10], vi[13], vi[12], vi[15], vi[14])
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fmt.Fprintf(&out, "\tv16_int={ %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x }", vi[0], vi[1], vi[2], vi[3], vi[4], vi[5], vi[6], vi[7], vi[8], vi[9], vi[10], vi[11], vi[12], vi[13], vi[14], vi[15])
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buf.Seek(0, os.SEEK_SET)
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var v2 [2]float64
|
|
for i := range v2 {
|
|
binary.Read(buf, binary.LittleEndian, &v2[i])
|
|
}
|
|
fmt.Fprintf(&out, "\tv2_float={ %g %g }", v2[0], v2[1])
|
|
|
|
buf.Seek(0, os.SEEK_SET)
|
|
var v4 [4]float32
|
|
for i := range v4 {
|
|
binary.Read(buf, binary.LittleEndian, &v4[i])
|
|
}
|
|
fmt.Fprintf(&out, "\tv4_float={ %g %g %g %g }", v4[0], v4[1], v4[2], v4[3])
|
|
|
|
return out.String()
|
|
} else if reg.Bytes == nil || (reg.Bytes != nil && len(reg.Bytes) < 16) {
|
|
return fmt.Sprintf("%#016x", reg.Uint64Val)
|
|
}
|
|
return fmt.Sprintf("%#x", reg.Bytes)
|
|
}
|