281f3920dd
TestStacktraceGoroutine failed intermittently on freebsd/amd64/go1.20. This happens because of two windows, in the scheduler (right after parking a goroutine and just before resuming a parked goroutine) where a thread is associated with a goroutine but running in the system stack and there is no systemstack_switch frame to connect the two stacks.
471 lines
15 KiB
Go
471 lines
15 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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"io"
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"math"
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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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"github.com/go-delve/delve/pkg/dwarf/regnum"
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)
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var amd64BreakInstruction = []byte{0xCC}
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// AMD64Arch returns an initialized AMD64
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// struct.
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func AMD64Arch(goos string) *Arch {
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return &Arch{
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Name: "amd64",
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ptrSize: 8,
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maxInstructionLength: 15,
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breakpointInstruction: amd64BreakInstruction,
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breakInstrMovesPC: true,
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derefTLS: goos == "windows",
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prologues: prologuesAMD64,
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fixFrameUnwindContext: amd64FixFrameUnwindContext,
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switchStack: amd64SwitchStack,
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regSize: amd64RegSize,
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RegistersToDwarfRegisters: amd64RegistersToDwarfRegisters,
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addrAndStackRegsToDwarfRegisters: amd64AddrAndStackRegsToDwarfRegisters,
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DwarfRegisterToString: amd64DwarfRegisterToString,
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inhibitStepInto: func(*BinaryInfo, uint64) bool { return false },
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asmDecode: amd64AsmDecode,
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PCRegNum: regnum.AMD64_Rip,
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SPRegNum: regnum.AMD64_Rsp,
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BPRegNum: regnum.AMD64_Rbp,
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ContextRegNum: regnum.AMD64_Rdx,
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asmRegisters: amd64AsmRegisters,
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RegisterNameToDwarf: nameToDwarfFunc(regnum.AMD64NameToDwarf),
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RegnumToString: regnum.AMD64ToName,
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debugCallMinStackSize: 256,
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maxRegArgBytes: 9*8 + 15*8,
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}
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}
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func amd64FixFrameUnwindContext(fctxt *frame.FrameContext, pc uint64, bi *BinaryInfo) *frame.FrameContext {
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a := bi.Arch
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if a.sigreturnfn == nil {
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a.sigreturnfn = bi.lookupOneFunc("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: regnum.AMD64_Rip,
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Regs: map[uint64]frame.DWRule{
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regnum.AMD64_Rip: {
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Rule: frame.RuleOffset,
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Offset: int64(-a.PtrSize()),
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},
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regnum.AMD64_Rbp: {
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Rule: frame.RuleOffset,
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Offset: int64(-2 * a.PtrSize()),
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},
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regnum.AMD64_Rsp: {
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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: regnum.AMD64_Rbp,
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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.lookupOneFunc("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 bi.GOOS {
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case "windows":
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rule.Offset += crosscall2SPOffsetWindowsAMD64
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default:
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rule.Offset += crosscall2SPOffset
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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[regnum.AMD64_Rbp].Rule == frame.RuleUndefined {
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fctxt.Regs[regnum.AMD64_Rbp] = frame.DWRule{
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Rule: frame.RuleFramePointer,
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Reg: regnum.AMD64_Rbp,
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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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// cgocallSPOffsetSaveSlot is the offset from systemstack.SP where
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// (goroutine.SP - StackHi) is saved in runtime.asmcgocall after the stack
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// switch happens.
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const amd64cgocallSPOffsetSaveSlot = 0x28
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func amd64SwitchStack(it *stackIterator, _ *op.DwarfRegisters) bool {
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if it.frame.Current.Fn == nil {
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if it.systemstack && it.g != nil && it.top {
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it.switchToGoroutineStack()
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return true
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}
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return false
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}
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switch it.frame.Current.Fn.Name {
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case "runtime.asmcgocall":
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if it.top || !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, uint64(it.regs.SP()+amd64cgocallSPOffsetSaveSlot), int64(it.bi.Arch.PtrSize())) // reads "offset of SP from StackHi" from where runtime.asmcgocall saved it
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oldsp := it.regs.SP()
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it.regs.Reg(it.regs.SPRegNum).Uint64Val = 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 it.regs.SP() == oldsp {
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return false
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}
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it.systemstack = false
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// advances to the next frame in the call stack
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addrret := uint64(int64(it.regs.SP()) + int64(it.bi.Arch.PtrSize()))
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it.frame.Ret, _ = readUintRaw(it.mem, addrret, int64(it.bi.Arch.PtrSize()))
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it.pc = it.frame.Ret
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it.top = false
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return true
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case "runtime.cgocallback_gofunc", "runtime.cgocallback":
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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_amd64.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.top || 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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it.regs.Reg(it.regs.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, uint64(it.regs.SP()), int64(it.bi.Arch.PtrSize()))
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it.top = false
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callFrameRegs, ret, retaddr := it.advanceRegs()
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frameOnSystemStack := it.newStackframe(ret, retaddr)
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it.pc = frameOnSystemStack.Ret
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it.regs = callFrameRegs
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it.systemstack = true
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return true
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case "runtime.goexit", "runtime.rt0_go":
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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 "runtime.mcall":
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if it.systemstack && it.g != nil {
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it.switchToGoroutineStack()
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return true
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}
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it.atend = true
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return true
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case "runtime.mstart":
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// Calls to runtime.systemstack will switch to the systemstack then:
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// 1. alter the goroutine stack so that it looks like systemstack_switch
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// was called
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// 2. alter the system stack so that it looks like the bottom-most frame
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// belongs to runtime.mstart
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// If we find a runtime.mstart frame on the system stack of a goroutine
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// parked on runtime.systemstack_switch we assume runtime.systemstack was
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// called and continue tracing from the parked position.
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if it.top || !it.systemstack || it.g == nil {
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return false
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}
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if fn := it.bi.PCToFunc(it.g.PC); fn == nil || fn.Name != "runtime.systemstack_switch" {
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return false
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}
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it.switchToGoroutineStack()
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return true
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case "runtime.newstack", "runtime.systemstack":
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if it.systemstack && it.g != nil {
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it.switchToGoroutineStack()
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return true
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}
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return false
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default:
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return false
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}
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}
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// amd64RegSize returns the size (in bytes) of register regnum.
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// The mapping between hardware registers and DWARF registers is specified
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// in the System V ABI AMD64 Architecture Processor Supplement page 57,
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// figure 3.36
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// https://www.uclibc.org/docs/psABI-x86_64.pdf
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func amd64RegSize(rn uint64) int {
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// XMM registers
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if rn > regnum.AMD64_Rip && rn <= 32 {
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return 16
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}
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// x87 registers
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if rn >= 33 && rn <= 40 {
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return 10
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}
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return 8
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}
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func amd64RegistersToDwarfRegisters(staticBase uint64, regs Registers) *op.DwarfRegisters {
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dregs := initDwarfRegistersFromSlice(int(regnum.AMD64MaxRegNum()), regs, regnum.AMD64NameToDwarf)
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dr := op.NewDwarfRegisters(staticBase, dregs, binary.LittleEndian, regnum.AMD64_Rip, regnum.AMD64_Rsp, regnum.AMD64_Rbp, 0)
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dr.SetLoadMoreCallback(loadMoreDwarfRegistersFromSliceFunc(dr, regs, regnum.AMD64NameToDwarf))
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return dr
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}
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func initDwarfRegistersFromSlice(maxRegs int, regs Registers, nameToDwarf map[string]int) []*op.DwarfRegister {
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dregs := make([]*op.DwarfRegister, maxRegs+1)
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regslice, _ := regs.Slice(false)
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for _, reg := range regslice {
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if dwarfReg, ok := nameToDwarf[strings.ToLower(reg.Name)]; ok {
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dregs[dwarfReg] = reg.Reg
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}
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}
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return dregs
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}
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func loadMoreDwarfRegistersFromSliceFunc(dr *op.DwarfRegisters, regs Registers, nameToDwarf map[string]int) func() {
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return func() {
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regslice, err := regs.Slice(true)
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dr.FloatLoadError = err
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for _, reg := range regslice {
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name := strings.ToLower(reg.Name)
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if dwarfReg, ok := nameToDwarf[name]; ok {
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dr.AddReg(uint64(dwarfReg), reg.Reg)
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} else if reg.Reg.Bytes != nil && (strings.HasPrefix(name, "ymm") || strings.HasPrefix(name, "zmm")) {
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xmmIdx, ok := nameToDwarf["x"+name[1:]]
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if !ok {
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continue
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}
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xmmReg := dr.Reg(uint64(xmmIdx))
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if xmmReg == nil || xmmReg.Bytes == nil {
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continue
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}
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nb := make([]byte, 0, len(xmmReg.Bytes)+len(reg.Reg.Bytes))
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nb = append(nb, xmmReg.Bytes...)
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nb = append(nb, reg.Reg.Bytes...)
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xmmReg.Bytes = nb
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}
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}
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}
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}
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func amd64AddrAndStackRegsToDwarfRegisters(staticBase, pc, sp, bp, lr uint64) op.DwarfRegisters {
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dregs := make([]*op.DwarfRegister, regnum.AMD64_Rip+1)
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dregs[regnum.AMD64_Rip] = op.DwarfRegisterFromUint64(pc)
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dregs[regnum.AMD64_Rsp] = op.DwarfRegisterFromUint64(sp)
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dregs[regnum.AMD64_Rbp] = op.DwarfRegisterFromUint64(bp)
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return *op.NewDwarfRegisters(staticBase, dregs, binary.LittleEndian, regnum.AMD64_Rip, regnum.AMD64_Rsp, regnum.AMD64_Rbp, 0)
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}
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func amd64DwarfRegisterToString(i int, reg *op.DwarfRegister) (name string, floatingPoint bool, repr string) {
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name = regnum.AMD64ToName(uint64(i))
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if reg == nil {
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return name, false, ""
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}
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switch n := strings.ToLower(name); n {
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case "rflags":
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return name, false, eflagsDescription.Describe(reg.Uint64Val, 64)
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case "cw", "sw", "tw", "fop":
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return name, true, fmt.Sprintf("%#04x", reg.Uint64Val)
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case "mxcsr_mask":
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return name, true, fmt.Sprintf("%#08x", reg.Uint64Val)
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case "mxcsr":
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return name, true, mxcsrDescription.Describe(reg.Uint64Val, 32)
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default:
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if reg.Bytes != nil && strings.HasPrefix(n, "xmm") {
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return name, true, formatSSEReg(name, reg.Bytes)
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} else if reg.Bytes != nil && strings.HasPrefix(n, "st(") {
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return name, true, formatX87Reg(reg.Bytes)
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} else if reg.Bytes == nil || (reg.Bytes != nil && len(reg.Bytes) <= 8) {
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return name, false, fmt.Sprintf("%#016x", reg.Uint64Val)
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} else {
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return name, false, fmt.Sprintf("%#x", reg.Bytes)
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}
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}
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}
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func formatSSEReg(name string, reg []byte) string {
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out := new(bytes.Buffer)
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formatSSERegInternal(reg, out)
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if len(reg) < 32 {
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return out.String()
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}
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fmt.Fprintf(out, "\n\t[%sh] ", "Y"+name[1:])
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formatSSERegInternal(reg[16:], out)
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if len(reg) < 64 {
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return out.String()
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}
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fmt.Fprintf(out, "\n\t[%shl] ", "Z"+name[1:])
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formatSSERegInternal(reg[32:], out)
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fmt.Fprintf(out, "\n\t[%shh] ", "Z"+name[1:])
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formatSSERegInternal(reg[48:], out)
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return out.String()
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}
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func formatSSERegInternal(xmm []byte, out *bytes.Buffer) {
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buf := bytes.NewReader(xmm)
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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, io.SeekStart)
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var v2 [2]float64
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for i := range v2 {
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binary.Read(buf, binary.LittleEndian, &v2[i])
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}
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fmt.Fprintf(out, "\tv2_float={ %g %g }", v2[0], v2[1])
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buf.Seek(0, io.SeekStart)
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var v4 [4]float32
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for i := range v4 {
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binary.Read(buf, binary.LittleEndian, &v4[i])
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}
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fmt.Fprintf(out, "\tv4_float={ %g %g %g %g }", v4[0], v4[1], v4[2], v4[3])
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}
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func formatX87Reg(b []byte) string {
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if len(b) < 10 {
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return fmt.Sprintf("%#x", b)
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}
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mantissa := binary.LittleEndian.Uint64(b[:8])
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exponent := uint16(binary.LittleEndian.Uint16(b[8:]))
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var f float64
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fset := false
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const (
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_SIGNBIT = 1 << 15
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_EXP_BIAS = (1 << 14) - 1 // 2^(n-1) - 1 = 16383
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_SPECIALEXP = (1 << 15) - 1 // all bits set
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_HIGHBIT = 1 << 63
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_QUIETBIT = 1 << 62
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)
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sign := 1.0
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if exponent&_SIGNBIT != 0 {
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sign = -1.0
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}
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exponent &= ^uint16(_SIGNBIT)
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NaN := math.NaN()
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Inf := math.Inf(+1)
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switch exponent {
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case 0:
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switch {
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case mantissa == 0:
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f = sign * 0.0
|
|
fset = true
|
|
case mantissa&_HIGHBIT != 0:
|
|
f = NaN
|
|
fset = true
|
|
}
|
|
case _SPECIALEXP:
|
|
switch {
|
|
case mantissa&_HIGHBIT == 0:
|
|
f = sign * Inf
|
|
fset = true
|
|
default:
|
|
f = NaN // signaling NaN
|
|
fset = true
|
|
}
|
|
default:
|
|
if mantissa&_HIGHBIT == 0 {
|
|
f = NaN
|
|
fset = true
|
|
}
|
|
}
|
|
|
|
if !fset {
|
|
significand := float64(mantissa) / (1 << 63)
|
|
f = sign * math.Ldexp(significand, int(exponent-_EXP_BIAS))
|
|
}
|
|
|
|
var buf bytes.Buffer
|
|
binary.Write(&buf, binary.LittleEndian, exponent)
|
|
binary.Write(&buf, binary.LittleEndian, mantissa)
|
|
|
|
return fmt.Sprintf("%#04x%016x\t%g", exponent, mantissa, f)
|
|
}
|