74c98bc961
Support for position independent executables (PIE) on the native linux backend, the gdbserver backend on linux and the core backend. Also implemented in the windows native backend, but it can't be tested because go doesn't support PIE on windows yet.
307 lines
8.5 KiB
Go
307 lines
8.5 KiB
Go
package proc
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import (
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"encoding/binary"
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"github.com/derekparker/delve/pkg/dwarf/frame"
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"github.com/derekparker/delve/pkg/dwarf/op"
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"golang.org/x/arch/x86/x86asm"
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)
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// Arch defines an interface for representing a
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// CPU architecture.
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type Arch interface {
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PtrSize() int
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BreakpointInstruction() []byte
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BreakpointSize() int
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DerefTLS() bool
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FixFrameUnwindContext(fctxt *frame.FrameContext, pc uint64, bi *BinaryInfo) *frame.FrameContext
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RegSize(uint64) int
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RegistersToDwarfRegisters(regs Registers, staticBase uint64) op.DwarfRegisters
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GoroutineToDwarfRegisters(*G) op.DwarfRegisters
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}
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// AMD64 represents the AMD64 CPU architecture.
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type AMD64 struct {
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ptrSize int
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breakInstruction []byte
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breakInstructionLen int
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gStructOffset uint64
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hardwareBreakpointUsage []bool
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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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amd64DwarfIPRegNum uint64 = 16
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amd64DwarfSPRegNum uint64 = 7
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amd64DwarfBPRegNum uint64 = 6
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)
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// AMD64Arch returns an initialized AMD64
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// struct.
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func AMD64Arch(goos string) *AMD64 {
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var breakInstr = []byte{0xCC}
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return &AMD64{
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ptrSize: 8,
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breakInstruction: breakInstr,
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breakInstructionLen: len(breakInstr),
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hardwareBreakpointUsage: make([]bool, 4),
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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 *AMD64) PtrSize() int {
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return a.ptrSize
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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 *AMD64) BreakpointInstruction() []byte {
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return a.breakInstruction
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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 *AMD64) BreakpointSize() int {
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return a.breakInstructionLen
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}
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// DerefTLS returns true if the value of regs.TLS()+GStructOffset() is a
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// pointer to the G struct
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func (a *AMD64) DerefTLS() bool {
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return a.goos == "windows"
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}
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const (
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crosscall2SPOffsetBad = 0x8
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crosscall2SPOffsetWindows = 0x118
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crosscall2SPOffsetNonWindows = 0x58
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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 *AMD64) 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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//if true {
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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: amd64DwarfIPRegNum,
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Regs: map[uint64]frame.DWRule{
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amd64DwarfIPRegNum: 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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amd64DwarfBPRegNum: 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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amd64DwarfSPRegNum: 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: amd64DwarfBPRegNum,
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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[amd64DwarfBPRegNum].Rule == frame.RuleUndefined {
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fctxt.Regs[amd64DwarfBPRegNum] = frame.DWRule{
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Rule: frame.RuleFramePointer,
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Reg: amd64DwarfBPRegNum,
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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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// RegSize 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 (a *AMD64) RegSize(regnum uint64) int {
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// XMM registers
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if regnum > amd64DwarfIPRegNum && regnum <= 32 {
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return 16
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}
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// x87 registers
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if regnum >= 33 && regnum <= 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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// 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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var asm64DwarfToHardware = map[int]x86asm.Reg{
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0: x86asm.RAX,
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1: x86asm.RDX,
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2: x86asm.RCX,
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3: x86asm.RBX,
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4: x86asm.RSI,
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5: x86asm.RDI,
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8: x86asm.R8,
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9: x86asm.R9,
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10: x86asm.R10,
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11: x86asm.R11,
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12: x86asm.R12,
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13: x86asm.R13,
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14: x86asm.R14,
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15: x86asm.R15,
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}
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var amd64DwarfToName = map[int]string{
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17: "XMM0",
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18: "XMM1",
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19: "XMM2",
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20: "XMM3",
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21: "XMM4",
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22: "XMM5",
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23: "XMM6",
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24: "XMM7",
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25: "XMM8",
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26: "XMM9",
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27: "XMM10",
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28: "XMM11",
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29: "XMM12",
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30: "XMM13",
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31: "XMM14",
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32: "XMM15",
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33: "ST(0)",
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34: "ST(1)",
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35: "ST(2)",
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36: "ST(3)",
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37: "ST(4)",
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38: "ST(5)",
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39: "ST(6)",
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40: "ST(7)",
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49: "Eflags",
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50: "Es",
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51: "Cs",
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52: "Ss",
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53: "Ds",
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54: "Fs",
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55: "Gs",
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58: "Fs_base",
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59: "Gs_base",
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64: "MXCSR",
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65: "CW",
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66: "SW",
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}
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func maxAmd64DwarfRegister() int {
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max := int(amd64DwarfIPRegNum)
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for i := range asm64DwarfToHardware {
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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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for i := range amd64DwarfToName {
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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 *AMD64) RegistersToDwarfRegisters(regs Registers, staticBase uint64) op.DwarfRegisters {
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dregs := make([]*op.DwarfRegister, maxAmd64DwarfRegister()+1)
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dregs[amd64DwarfIPRegNum] = op.DwarfRegisterFromUint64(regs.PC())
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dregs[amd64DwarfSPRegNum] = op.DwarfRegisterFromUint64(regs.SP())
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dregs[amd64DwarfBPRegNum] = op.DwarfRegisterFromUint64(regs.BP())
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for dwarfReg, asmReg := range asm64DwarfToHardware {
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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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for _, reg := range regs.Slice() {
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for dwarfReg, regName := range amd64DwarfToName {
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if regName == reg.Name {
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dregs[dwarfReg] = op.DwarfRegisterFromBytes(reg.Bytes)
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}
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}
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}
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return op.DwarfRegisters{StaticBase: staticBase, Regs: dregs, ByteOrder: binary.LittleEndian, PCRegNum: amd64DwarfIPRegNum, SPRegNum: amd64DwarfSPRegNum, BPRegNum: amd64DwarfBPRegNum}
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}
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// GoroutineToDwarfRegisters extract the saved DWARF registers from a parked
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// goroutine in the format used by the DWARF expression interpreter.
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func (a *AMD64) GoroutineToDwarfRegisters(g *G) op.DwarfRegisters {
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dregs := make([]*op.DwarfRegister, amd64DwarfIPRegNum+1)
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dregs[amd64DwarfIPRegNum] = op.DwarfRegisterFromUint64(g.PC)
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dregs[amd64DwarfSPRegNum] = op.DwarfRegisterFromUint64(g.SP)
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dregs[amd64DwarfBPRegNum] = op.DwarfRegisterFromUint64(g.BP)
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return op.DwarfRegisters{StaticBase: g.variable.bi.staticBase, Regs: dregs, ByteOrder: binary.LittleEndian, PCRegNum: amd64DwarfIPRegNum, SPRegNum: amd64DwarfSPRegNum, BPRegNum: amd64DwarfBPRegNum}
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}
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