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bee/vendor/github.com/derekparker/delve/pkg/proc/disasm.go
2018-10-13 21:45:53 +08:00

122 lines
3.4 KiB
Go

package proc
import "sort"
// AsmInstruction represents one assembly instruction.
type AsmInstruction struct {
Loc Location
DestLoc *Location
Bytes []byte
Breakpoint bool
AtPC bool
Inst *archInst
}
// AssemblyFlavour is the assembly syntax to display.
type AssemblyFlavour int
const (
// GNUFlavour will display GNU assembly syntax.
GNUFlavour = AssemblyFlavour(iota)
// IntelFlavour will display Intel assembly syntax.
IntelFlavour
// GoFlavour will display Go assembly syntax.
GoFlavour
)
// Disassemble disassembles target memory between startPC and endPC, marking
// the current instruction being executed in goroutine g.
// If currentGoroutine is set and thread is stopped at a CALL instruction Disassemble will evaluate the argument of the CALL instruction using the thread's registers
// Be aware that the Bytes field of each returned instruction is a slice of a larger array of size endPC - startPC
func Disassemble(dbp Process, g *G, startPC, endPC uint64) ([]AsmInstruction, error) {
if _, err := dbp.Valid(); err != nil {
return nil, err
}
if g == nil {
ct := dbp.CurrentThread()
regs, _ := ct.Registers(false)
return disassemble(ct, regs, dbp.Breakpoints(), dbp.BinInfo(), startPC, endPC, false)
}
var regs Registers
var mem MemoryReadWriter = dbp.CurrentThread()
if g.Thread != nil {
mem = g.Thread
regs, _ = g.Thread.Registers(false)
}
return disassemble(mem, regs, dbp.Breakpoints(), dbp.BinInfo(), startPC, endPC, false)
}
func disassemble(memrw MemoryReadWriter, regs Registers, breakpoints *BreakpointMap, bi *BinaryInfo, startPC, endPC uint64, singleInstr bool) ([]AsmInstruction, error) {
mem := make([]byte, int(endPC-startPC))
_, err := memrw.ReadMemory(mem, uintptr(startPC))
if err != nil {
return nil, err
}
r := make([]AsmInstruction, 0, len(mem)/15)
pc := startPC
var curpc uint64
if regs != nil {
curpc = regs.PC()
}
for len(mem) > 0 {
bp, atbp := breakpoints.M[pc]
if atbp {
for i := range bp.OriginalData {
mem[i] = bp.OriginalData[i]
}
}
file, line, fn := bi.PCToLine(pc)
loc := Location{PC: pc, File: file, Line: line, Fn: fn}
inst, err := asmDecode(mem, pc)
if err == nil {
atpc := (regs != nil) && (curpc == pc)
destloc := resolveCallArg(inst, atpc, regs, memrw, bi)
r = append(r, AsmInstruction{Loc: loc, DestLoc: destloc, Bytes: mem[:inst.Len], Breakpoint: atbp, AtPC: atpc, Inst: inst})
pc += uint64(inst.Size())
mem = mem[inst.Size():]
} else {
r = append(r, AsmInstruction{Loc: loc, Bytes: mem[:1], Breakpoint: atbp, Inst: nil})
pc++
mem = mem[1:]
}
if singleInstr {
break
}
}
return r, nil
}
// Looks up symbol (either functions or global variables) at address addr.
// Used by disassembly formatter.
func (bi *BinaryInfo) symLookup(addr uint64) (string, uint64) {
fn := bi.PCToFunc(addr)
if fn != nil {
if fn.Entry == addr {
// only report the function name if it's the exact address because it's
// easier to read the absolute address than function_name+offset.
return fn.Name, fn.Entry
}
return "", 0
}
i := sort.Search(len(bi.packageVars), func(i int) bool {
return bi.packageVars[i].addr >= addr
})
if i >= len(bi.packageVars) {
return "", 0
}
if bi.packageVars[i].addr > addr {
// report previous variable + offset if i-th variable starts after addr
i--
}
if i > 0 {
return bi.packageVars[i].name, bi.packageVars[i].addr
}
return "", 0
}