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Commit ac81c5c4 authored by Heschi Kreinick's avatar Heschi Kreinick
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cmd/compile/internal/ssa: refactor buildLocationLists 

Change the closures to methods on debugState, mostly just for aesthetic
reasons.

Change-Id: I5242807f7300efafc7efb4eb3bd305ac3ec8e826
Reviewed-on: https://go-review.googlesource.com/92403Reviewed-by: 's avatarDavid Chase <drchase@google.com>
parent e181852d
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Showing with 103 additions and 98 deletions
src/cmd/compile/internal/ssa/debug.go
View file @ ac81c5c4
......@@ -167,6 +167,7 @@ type debugState struct {
slots []*LocalSlot
vars []GCNode
varSlots [][]SlotID
lists [][]byte
// The user variable that each slot rolls up to, indexed by SlotID.
slotVars []VarID
......@@ -176,6 +177,7 @@ type debugState struct {
cache *Cache
registers []Register
stackOffset func(LocalSlot) int32
ctxt *obj.Link
// The names (slots) associated with each value, indexed by Value ID.
valueNames [][]SlotID
......@@ -184,6 +186,9 @@ type debugState struct {
currentState stateAtPC
liveCount []int
changedVars *sparseSet
// The pending location list entry for each user variable, indexed by VarID.
pendingEntries []pendingEntry
}
func (state *debugState) initializeCache() {
......@@ -251,6 +256,7 @@ func (state *debugState) initializeCache() {
}
freePieceIdx += len(slots)
}
state.pendingEntries = pe
}
func (state *debugState) allocBlock(b *Block) *BlockDebug {
......@@ -303,6 +309,7 @@ func BuildFuncDebug(ctxt *obj.Link, f *Func, loggingEnabled bool, stackOffset fu
cache: f.Cache,
registers: f.Config.registers,
stackOffset: stackOffset,
ctxt: ctxt,
}
// Recompose any decomposed variables, and record the names associated with each value.
......@@ -327,6 +334,8 @@ func BuildFuncDebug(ctxt *obj.Link, f *Func, loggingEnabled bool, stackOffset fu
// Fill in the var<->slot mappings.
state.varSlots = make([][]SlotID, len(state.vars))
state.slotVars = make([]VarID, len(state.slots))
state.lists = make([][]byte, len(state.vars))
for varID, n := range state.vars {
parts := varParts[n]
state.varSlots[varID] = parts
......@@ -347,13 +356,13 @@ func BuildFuncDebug(ctxt *obj.Link, f *Func, loggingEnabled bool, stackOffset fu
}
blockLocs := state.liveness()
lists := state.buildLocationLists(ctxt, blockLocs)
state.buildLocationLists(blockLocs)
return &FuncDebug{
Slots: state.slots,
VarSlots: state.varSlots,
Vars: state.vars,
LocationLists: lists,
LocationLists: state.lists,
}
}
......@@ -717,78 +726,59 @@ func firstReg(set RegisterSet) uint8 {
// The returned location lists are not fully complete. They are in terms of
// SSA values rather than PCs, and have no base address/end entries. They will
// be finished by PutLocationList.
func (state *debugState) buildLocationLists(Ctxt *obj.Link, blockLocs []*BlockDebug) [][]byte {
lists := make([][]byte, len(state.vars))
pendingEntries := state.cache.pendingEntries
// writePendingEntry writes out the pending entry for varID, if any,
// terminated at endBlock/Value.
writePendingEntry := func(varID VarID, endBlock, endValue ID) {
list := lists[varID]
pending := pendingEntries[varID]
if !pending.present {
return
}
func (state *debugState) buildLocationLists(blockLocs []*BlockDebug) {
// Run through the function in program text order, building up location
// lists as we go. The heavy lifting has mostly already been done.
for _, b := range state.f.Blocks {
state.mergePredecessors(b, blockLocs)
// Pack the start/end coordinates into the start/end addresses
// of the entry, for decoding by PutLocationList.
start, startOK := encodeValue(Ctxt, pending.startBlock, pending.startValue)
end, endOK := encodeValue(Ctxt, endBlock, endValue)
if !startOK || !endOK {
// If someone writes a function that uses >65K values,
// they get incomplete debug info on 32-bit platforms.
return
}
list = appendPtr(Ctxt, list, start)
list = appendPtr(Ctxt, list, end)
// Where to write the length of the location description once
// we know how big it is.
sizeIdx := len(list)
list = list[:len(list)+2]
phisPending := false
for _, v := range b.Values {
slots := state.valueNames[v.ID]
reg, _ := state.f.getHome(v.ID).(*Register)
changed := state.processValue(v, slots, reg)
if state.loggingEnabled {
var partStrs []string
for i, slot := range state.varSlots[varID] {
partStrs = append(partStrs, fmt.Sprintf("%v@%v", state.slots[slot], state.LocString(pending.pieces[i])))
if v.Op == OpPhi {
if changed {
phisPending = true
}
state.logf("Add entry for %v: \tb%vv%v-b%vv%v = \t%v\n", state.vars[varID], pending.startBlock, pending.startValue, endBlock, endValue, strings.Join(partStrs, " "))
continue
}
for i, slotID := range state.varSlots[varID] {
loc := pending.pieces[i]
slot := state.slots[slotID]
if !changed && !phisPending {
continue
}
if !loc.absent() {
if loc.onStack() {
if loc.stackOffsetValue() == 0 {
list = append(list, dwarf.DW_OP_call_frame_cfa)
} else {
list = append(list, dwarf.DW_OP_fbreg)
list = dwarf.AppendSleb128(list, int64(loc.stackOffsetValue()))
phisPending = false
for _, varID := range state.changedVars.contents() {
state.updateVar(VarID(varID), v, state.currentState.slots)
}
} else {
regnum := Ctxt.Arch.DWARFRegisters[state.registers[firstReg(loc.Registers)].ObjNum()]
if regnum < 32 {
list = append(list, dwarf.DW_OP_reg0+byte(regnum))
} else {
list = append(list, dwarf.DW_OP_regx)
list = dwarf.AppendUleb128(list, uint64(regnum))
state.changedVars.clear()
}
}
if state.loggingEnabled {
state.logf("location lists:\n")
}
if len(state.varSlots[varID]) > 1 {
list = append(list, dwarf.DW_OP_piece)
list = dwarf.AppendUleb128(list, uint64(slot.Type.Size()))
// Flush any leftover entries live at the end of the last block.
for varID := range state.lists {
state.writePendingEntry(VarID(varID), state.f.Blocks[len(state.f.Blocks)-1].ID, BlockEnd.ID)
list := state.lists[varID]
if len(list) == 0 {
continue
}
if state.loggingEnabled {
state.logf("\t%v : %q\n", state.vars[varID], hex.EncodeToString(state.lists[varID]))
}
Ctxt.Arch.ByteOrder.PutUint16(list[sizeIdx:], uint16(len(list)-sizeIdx-2))
lists[varID] = list
}
}
// updateVar updates the pending location list entry for varID to
// reflect the new locations in curLoc, caused by v.
updateVar := func(varID VarID, v *Value, curLoc []VarLoc) {
// updateVar updates the pending location list entry for varID to
// reflect the new locations in curLoc, caused by v.
func (state *debugState) updateVar(varID VarID, v *Value, curLoc []VarLoc) {
// Assemble the location list entry with whatever's live.
empty := true
for _, slotID := range state.varSlots[varID] {
......@@ -797,9 +787,9 @@ func (state *debugState) buildLocationLists(Ctxt *obj.Link, blockLocs []*BlockDe
break
}
}
pending := &pendingEntries[varID]
pending := &state.pendingEntries[varID]
if empty {
writePendingEntry(varID, v.Block.ID, v.ID)
state.writePendingEntry(varID, v.Block.ID, v.ID)
pending.clear()
return
}
......@@ -818,7 +808,7 @@ func (state *debugState) buildLocationLists(Ctxt *obj.Link, blockLocs []*BlockDe
}
}
writePendingEntry(varID, v.Block.ID, v.ID)
state.writePendingEntry(varID, v.Block.ID, v.ID)
pending.present = true
pending.startBlock = v.Block.ID
pending.startValue = v.ID
......@@ -827,56 +817,71 @@ func (state *debugState) buildLocationLists(Ctxt *obj.Link, blockLocs []*BlockDe
}
return
}
// Run through the function in program text order, building up location
// lists as we go. The heavy lifting has mostly already been done.
for _, b := range state.f.Blocks {
state.mergePredecessors(b, blockLocs)
phisPending := false
for _, v := range b.Values {
slots := state.valueNames[v.ID]
reg, _ := state.f.getHome(v.ID).(*Register)
changed := state.processValue(v, slots, reg)
}
if v.Op == OpPhi {
if changed {
phisPending = true
}
continue
// writePendingEntry writes out the pending entry for varID, if any,
// terminated at endBlock/Value.
func (state *debugState) writePendingEntry(varID VarID, endBlock, endValue ID) {
pending := state.pendingEntries[varID]
if !pending.present {
return
}
if !changed && !phisPending {
continue
// Pack the start/end coordinates into the start/end addresses
// of the entry, for decoding by PutLocationList.
start, startOK := encodeValue(state.ctxt, pending.startBlock, pending.startValue)
end, endOK := encodeValue(state.ctxt, endBlock, endValue)
if !startOK || !endOK {
// If someone writes a function that uses >65K values,
// they get incomplete debug info on 32-bit platforms.
return
}
list := state.lists[varID]
list = appendPtr(state.ctxt, list, start)
list = appendPtr(state.ctxt, list, end)
// Where to write the length of the location description once
// we know how big it is.
sizeIdx := len(list)
list = list[:len(list)+2]
phisPending = false
for _, varID := range state.changedVars.contents() {
updateVar(VarID(varID), v, state.currentState.slots)
if state.loggingEnabled {
var partStrs []string
for i, slot := range state.varSlots[varID] {
partStrs = append(partStrs, fmt.Sprintf("%v@%v", state.slots[slot], state.LocString(pending.pieces[i])))
}
state.changedVars.clear()
state.logf("Add entry for %v: \tb%vv%v-b%vv%v = \t%v\n", state.vars[varID], pending.startBlock, pending.startValue, endBlock, endValue, strings.Join(partStrs, " "))
}
}
for i, slotID := range state.varSlots[varID] {
loc := pending.pieces[i]
slot := state.slots[slotID]
if state.loggingEnabled {
state.logf("location lists:\n")
if !loc.absent() {
if loc.onStack() {
if loc.stackOffsetValue() == 0 {
list = append(list, dwarf.DW_OP_call_frame_cfa)
} else {
list = append(list, dwarf.DW_OP_fbreg)
list = dwarf.AppendSleb128(list, int64(loc.stackOffsetValue()))
}
} else {
regnum := state.ctxt.Arch.DWARFRegisters[state.registers[firstReg(loc.Registers)].ObjNum()]
if regnum < 32 {
list = append(list, dwarf.DW_OP_reg0+byte(regnum))
} else {
list = append(list, dwarf.DW_OP_regx)
list = dwarf.AppendUleb128(list, uint64(regnum))
}
}
// Flush any leftover entries live at the end of the last block.
for varID := range lists {
writePendingEntry(VarID(varID), state.f.Blocks[len(state.f.Blocks)-1].ID, BlockEnd.ID)
list := lists[varID]
if len(list) == 0 {
continue
}
if state.loggingEnabled {
state.logf("\t%v : %q\n", state.vars[varID], hex.EncodeToString(lists[varID]))
if len(state.varSlots[varID]) > 1 {
list = append(list, dwarf.DW_OP_piece)
list = dwarf.AppendUleb128(list, uint64(slot.Type.Size()))
}
}
return lists
state.ctxt.Arch.ByteOrder.PutUint16(list[sizeIdx:], uint16(len(list)-sizeIdx-2))
state.lists[varID] = list
}
// PutLocationList adds list (a location list in its intermediate representation) to listSym.
......
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