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path: root/src/cmd/internal/dwarf/dwarf.go
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Diffstat (limited to 'src/cmd/internal/dwarf/dwarf.go')
-rw-r--r--src/cmd/internal/dwarf/dwarf.go130
1 files changed, 95 insertions, 35 deletions
diff --git a/src/cmd/internal/dwarf/dwarf.go b/src/cmd/internal/dwarf/dwarf.go
index b58052beb3..2b034257a6 100644
--- a/src/cmd/internal/dwarf/dwarf.go
+++ b/src/cmd/internal/dwarf/dwarf.go
@@ -15,6 +15,9 @@ import (
// InfoPrefix is the prefix for all the symbols containing DWARF info entries.
const InfoPrefix = "go.info."
+// RangePrefix is the prefix for all the symbols containing DWARF location lists.
+const LocPrefix = "go.loc."
+
// RangePrefix is the prefix for all the symbols containing DWARF range lists.
const RangePrefix = "go.range."
@@ -23,13 +26,31 @@ type Sym interface {
Len() int64
}
+// A Location represents a variable's location at a particular PC range.
+// It becomes a location list entry in the DWARF.
+type Location struct {
+ StartPC, EndPC int64
+ Pieces []Piece
+}
+
+// A Piece represents the location of a particular part of a variable.
+// It becomes part of a location list entry (a DW_OP_piece) in the DWARF.
+type Piece struct {
+ Length int64
+ StackOffset int32
+ RegNum int16
+ Missing bool
+ OnStack bool // if true, RegNum is unset.
+}
+
// A Var represents a local variable or a function parameter.
type Var struct {
- Name string
- Abbrev int // Either DW_ABRV_AUTO or DW_ABRV_PARAM
- StackOffset int32
- Scope int32
- Type Sym
+ Name string
+ Abbrev int // Either DW_ABRV_AUTO or DW_ABRV_PARAM
+ StackOffset int32
+ LocationList []Location
+ Scope int32
+ Type Sym
}
// A Scope represents a lexical scope. All variables declared within a
@@ -205,7 +226,7 @@ const (
)
// Index into the abbrevs table below.
-// Keep in sync with ispubname() and ispubtype() below.
+// Keep in sync with ispubname() and ispubtype() in ld/dwarf.go.
// ispubtype considers >= NULLTYPE public
const (
DW_ABRV_NULL = iota
@@ -709,31 +730,30 @@ func HasChildren(die *DWDie) bool {
// PutFunc writes a DIE for a function to s.
// It also writes child DIEs for each variable in vars.
-func PutFunc(ctxt Context, s, ranges Sym, name string, external bool, startPC Sym, size int64, scopes []Scope) error {
- Uleb128put(ctxt, s, DW_ABRV_FUNCTION)
- putattr(ctxt, s, DW_ABRV_FUNCTION, DW_FORM_string, DW_CLS_STRING, int64(len(name)), name)
- putattr(ctxt, s, DW_ABRV_FUNCTION, DW_FORM_addr, DW_CLS_ADDRESS, 0, startPC)
- putattr(ctxt, s, DW_ABRV_FUNCTION, DW_FORM_addr, DW_CLS_ADDRESS, size, startPC)
- putattr(ctxt, s, DW_ABRV_FUNCTION, DW_FORM_block1, DW_CLS_BLOCK, 1, []byte{DW_OP_call_frame_cfa})
+func PutFunc(ctxt Context, info, loc, ranges Sym, name string, external bool, startPC Sym, size int64, scopes []Scope) error {
+ Uleb128put(ctxt, info, DW_ABRV_FUNCTION)
+ putattr(ctxt, info, DW_ABRV_FUNCTION, DW_FORM_string, DW_CLS_STRING, int64(len(name)), name)
+ putattr(ctxt, info, DW_ABRV_FUNCTION, DW_FORM_addr, DW_CLS_ADDRESS, 0, startPC)
+ putattr(ctxt, info, DW_ABRV_FUNCTION, DW_FORM_addr, DW_CLS_ADDRESS, size, startPC)
+ putattr(ctxt, info, DW_ABRV_FUNCTION, DW_FORM_block1, DW_CLS_BLOCK, 1, []byte{DW_OP_call_frame_cfa})
var ev int64
if external {
ev = 1
}
- putattr(ctxt, s, DW_ABRV_FUNCTION, DW_FORM_flag, DW_CLS_FLAG, ev, 0)
+ putattr(ctxt, info, DW_ABRV_FUNCTION, DW_FORM_flag, DW_CLS_FLAG, ev, 0)
if len(scopes) > 0 {
var encbuf [20]byte
- if putscope(ctxt, s, ranges, startPC, 0, scopes, encbuf[:0]) < int32(len(scopes)) {
+ if putscope(ctxt, info, loc, ranges, startPC, 0, scopes, encbuf[:0]) < int32(len(scopes)) {
return errors.New("multiple toplevel scopes")
}
}
-
- Uleb128put(ctxt, s, 0)
+ Uleb128put(ctxt, info, 0)
return nil
}
-func putscope(ctxt Context, s, ranges Sym, startPC Sym, curscope int32, scopes []Scope, encbuf []byte) int32 {
+func putscope(ctxt Context, info, loc, ranges, startPC Sym, curscope int32, scopes []Scope, encbuf []byte) int32 {
for _, v := range scopes[curscope].Vars {
- putvar(ctxt, s, v, encbuf)
+ putvar(ctxt, info, loc, v, startPC, encbuf)
}
this := curscope
curscope++
@@ -744,12 +764,12 @@ func putscope(ctxt Context, s, ranges Sym, startPC Sym, curscope int32, scopes [
}
if len(scope.Ranges) == 1 {
- Uleb128put(ctxt, s, DW_ABRV_LEXICAL_BLOCK_SIMPLE)
- putattr(ctxt, s, DW_ABRV_LEXICAL_BLOCK_SIMPLE, DW_FORM_addr, DW_CLS_ADDRESS, scope.Ranges[0].Start, startPC)
- putattr(ctxt, s, DW_ABRV_LEXICAL_BLOCK_SIMPLE, DW_FORM_addr, DW_CLS_ADDRESS, scope.Ranges[0].End, startPC)
+ Uleb128put(ctxt, info, DW_ABRV_LEXICAL_BLOCK_SIMPLE)
+ putattr(ctxt, info, DW_ABRV_LEXICAL_BLOCK_SIMPLE, DW_FORM_addr, DW_CLS_ADDRESS, scope.Ranges[0].Start, startPC)
+ putattr(ctxt, info, DW_ABRV_LEXICAL_BLOCK_SIMPLE, DW_FORM_addr, DW_CLS_ADDRESS, scope.Ranges[0].End, startPC)
} else {
- Uleb128put(ctxt, s, DW_ABRV_LEXICAL_BLOCK_RANGES)
- putattr(ctxt, s, DW_ABRV_LEXICAL_BLOCK_RANGES, DW_FORM_sec_offset, DW_CLS_PTR, ranges.Len(), ranges)
+ Uleb128put(ctxt, info, DW_ABRV_LEXICAL_BLOCK_RANGES)
+ putattr(ctxt, info, DW_ABRV_LEXICAL_BLOCK_RANGES, DW_FORM_sec_offset, DW_CLS_PTR, ranges.Len(), ranges)
ctxt.AddAddress(ranges, nil, -1)
ctxt.AddAddress(ranges, startPC, 0)
@@ -761,26 +781,66 @@ func putscope(ctxt Context, s, ranges Sym, startPC Sym, curscope int32, scopes [
ctxt.AddAddress(ranges, nil, 0)
}
- curscope = putscope(ctxt, s, ranges, startPC, curscope, scopes, encbuf)
+ curscope = putscope(ctxt, info, loc, ranges, startPC, curscope, scopes, encbuf)
- Uleb128put(ctxt, s, 0)
+ Uleb128put(ctxt, info, 0)
}
return curscope
}
-func putvar(ctxt Context, s Sym, v *Var, encbuf []byte) {
+func putvar(ctxt Context, info, loc Sym, v *Var, startPC Sym, encbuf []byte) {
n := v.Name
- Uleb128put(ctxt, s, int64(v.Abbrev))
- putattr(ctxt, s, v.Abbrev, DW_FORM_string, DW_CLS_STRING, int64(len(n)), n)
- loc := append(encbuf[:0], DW_OP_call_frame_cfa)
- if v.StackOffset != 0 {
- loc = append(loc, DW_OP_consts)
- loc = AppendSleb128(loc, int64(v.StackOffset))
- loc = append(loc, DW_OP_plus)
+ Uleb128put(ctxt, info, int64(v.Abbrev))
+ putattr(ctxt, info, v.Abbrev, DW_FORM_string, DW_CLS_STRING, int64(len(n)), n)
+ if v.Abbrev == DW_ABRV_AUTO_LOCLIST || v.Abbrev == DW_ABRV_PARAM_LOCLIST {
+ putattr(ctxt, info, v.Abbrev, DW_FORM_sec_offset, DW_CLS_PTR, int64(loc.Len()), loc)
+ addLocList(ctxt, loc, startPC, v, encbuf)
+ } else {
+ loc := append(encbuf[:0], DW_OP_call_frame_cfa)
+ if v.StackOffset != 0 {
+ loc = append(loc, DW_OP_consts)
+ loc = AppendSleb128(loc, int64(v.StackOffset))
+ loc = append(loc, DW_OP_plus)
+ }
+ putattr(ctxt, info, v.Abbrev, DW_FORM_block1, DW_CLS_BLOCK, int64(len(loc)), loc)
+ }
+ putattr(ctxt, info, v.Abbrev, DW_FORM_ref_addr, DW_CLS_REFERENCE, 0, v.Type)
+}
+
+func addLocList(ctxt Context, listSym, startPC Sym, v *Var, encbuf []byte) {
+ // Base address entry: max ptr followed by the base address.
+ ctxt.AddInt(listSym, ctxt.PtrSize(), ^0)
+ ctxt.AddAddress(listSym, startPC, 0)
+ for _, entry := range v.LocationList {
+ ctxt.AddInt(listSym, ctxt.PtrSize(), entry.StartPC)
+ ctxt.AddInt(listSym, ctxt.PtrSize(), entry.EndPC)
+ locBuf := encbuf[:0]
+ for _, piece := range entry.Pieces {
+ if !piece.Missing {
+ if piece.OnStack {
+ locBuf = append(locBuf, DW_OP_fbreg)
+ locBuf = AppendSleb128(locBuf, int64(piece.StackOffset))
+ } else {
+ if piece.RegNum < 32 {
+ locBuf = append(locBuf, DW_OP_reg0+byte(piece.RegNum))
+ } else {
+ locBuf = append(locBuf, DW_OP_regx)
+ locBuf = AppendUleb128(locBuf, uint64(piece.RegNum))
+ }
+ }
+ }
+ if len(entry.Pieces) > 1 {
+ locBuf = append(locBuf, DW_OP_piece)
+ locBuf = AppendUleb128(locBuf, uint64(piece.Length))
+ }
+ }
+ ctxt.AddInt(listSym, 2, int64(len(locBuf)))
+ ctxt.AddBytes(listSym, locBuf)
}
- putattr(ctxt, s, v.Abbrev, DW_FORM_block1, DW_CLS_BLOCK, int64(len(loc)), loc)
- putattr(ctxt, s, v.Abbrev, DW_FORM_ref_addr, DW_CLS_REFERENCE, 0, v.Type)
+ // End list
+ ctxt.AddInt(listSym, ctxt.PtrSize(), 0)
+ ctxt.AddInt(listSym, ctxt.PtrSize(), 0)
}
// VarsByOffset attaches the methods of sort.Interface to []*Var,
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