delve/pkg/dwarf/frame/entries.go
aarzilli f4e2000fc8 proc: refactor stack.go to use DWARF registers
Instead of only tracking a few cherrypicked registers in stack.go track
all DWARF registers.

This is needed for cgo code and for the locationlists emitted by go in
1.10:
* The debug_frame sections emitted by C compilers can not be used
  without tracking all registers
* the loclists emitted by go1.10 need all registers of a frame to be
  interpreted.
2017-11-17 10:17:24 -08:00

87 lines
2.0 KiB
Go

package frame
import (
"encoding/binary"
"fmt"
"sort"
)
// Represents a Common Information Entry in
// the Dwarf .debug_frame section.
type CommonInformationEntry struct {
Length uint32
CIE_id uint32
Version uint8
Augmentation string
CodeAlignmentFactor uint64
DataAlignmentFactor int64
ReturnAddressRegister uint64
InitialInstructions []byte
}
// Represents a Frame Descriptor Entry in the
// Dwarf .debug_frame section.
type FrameDescriptionEntry struct {
Length uint32
CIE *CommonInformationEntry
Instructions []byte
begin, end uint64
order binary.ByteOrder
}
// Returns whether or not the given address is within the
// bounds of this frame.
func (fde *FrameDescriptionEntry) Cover(addr uint64) bool {
return (addr - fde.begin) < fde.end
}
// Address of first location for this frame.
func (fde *FrameDescriptionEntry) Begin() uint64 {
return fde.begin
}
// Address of last location for this frame.
func (fde *FrameDescriptionEntry) End() uint64 {
return fde.begin + fde.end
}
// Set up frame for the given PC.
func (fde *FrameDescriptionEntry) EstablishFrame(pc uint64) *FrameContext {
return executeDwarfProgramUntilPC(fde, pc)
}
type FrameDescriptionEntries []*FrameDescriptionEntry
func NewFrameIndex() FrameDescriptionEntries {
return make(FrameDescriptionEntries, 0, 1000)
}
type NoFDEForPCError struct {
PC uint64
}
func (err *NoFDEForPCError) Error() string {
return fmt.Sprintf("could not find FDE for PC %#v", err.PC)
}
// Returns the Frame Description Entry for the given PC.
func (fdes FrameDescriptionEntries) FDEForPC(pc uint64) (*FrameDescriptionEntry, error) {
idx := sort.Search(len(fdes), func(i int) bool {
if fdes[i].Cover(pc) {
return true
}
if fdes[i].LessThan(pc) {
return false
}
return true
})
if idx == len(fdes) {
return nil, &NoFDEForPCError{pc}
}
return fdes[idx], nil
}
func (frame *FrameDescriptionEntry) LessThan(pc uint64) bool {
return frame.End() <= pc
}