qbit/go
1
0
Fork 0
mirror of https://github.com/golang/go synced 2024-11-26 05:07:59 -07:00
Code Releases Activity

[dev.typeparams] cmd/compile: simplify openDeferSave

Browse Source 
Now it is only used to save the deferred the function (closure),
which must be a function type. Simplify the code.

Change-Id: Id4b8f2760fbf39a95883df2327f97378e7edab88
Reviewed-on: https://go-review.googlesource.com/c/go/+/326060
Trust: Cherry Mui <cherryyz@google.com>
Run-TryBot: Cherry Mui <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
This commit is contained in:
Cherry Mui 2021-06-08 16:55:36 -04:00
parent 74b0b2772a
commit c0a86c10f1
1 changed files with 33 additions and 43 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

76
src/cmd/compile/internal/ssagen/ssa.go
View File

@ -4672,7 +4672,7 @@ func (s *state) openDeferRecord(n *ir.CallExpr) {
// runtime panic code to use. But in the defer exit code, we will
// call the function directly if it is a static function.
closureVal := s.expr(fn)
closure := s.openDeferSave(nil, fn.Type(), closureVal)
closure := s.openDeferSave(fn.Type(), closureVal)
opendefer.closureNode = closure.Aux.(*ir.Name)
if !(fn.Op() == ir.ONAME && fn.(*ir.Name).Class == ir.PFUNC) {
opendefer.closure = closure
@ -4690,57 +4690,47 @@ func (s *state) openDeferRecord(n *ir.CallExpr) {
// openDeferSave generates SSA nodes to store a value (with type t) for an
// open-coded defer at an explicit autotmp location on the stack, so it can be
// reloaded and used for the appropriate call on exit. If type t is SSAable, then
// val must be non-nil (and n should be nil) and val is the value to be stored. If
// type t is non-SSAable, then n must be non-nil (and val should be nil) and n is
// evaluated (via s.addr() below) to get the value that is to be stored. The
// function returns an SSA value representing a pointer to the autotmp location.
func (s *state) openDeferSave(n ir.Node, t *types.Type, val *ssa.Value) *ssa.Value {
canSSA := TypeOK(t)
var pos src.XPos
if canSSA {
pos = val.Pos
} else {
pos = n.Pos()
// reloaded and used for the appropriate call on exit. Type t must be a function type
// (therefore SSAable). val is the value to be stored. The function returns an SSA
// value representing a pointer to the autotmp location.
func (s *state) openDeferSave(t *types.Type, val *ssa.Value) *ssa.Value {
if !TypeOK(t) {
s.Fatalf("openDeferSave of non-SSA-able type %v val=%v", t, val)
}
argTemp := typecheck.TempAt(pos.WithNotStmt(), s.curfn, t)
argTemp.SetOpenDeferSlot(true)
var addrArgTemp *ssa.Value
// Use OpVarLive to make sure stack slots for the args, etc. are not
// removed by dead-store elimination
if !t.HasPointers() {
s.Fatalf("openDeferSave of pointerless type %v val=%v", t, val)
}
pos := val.Pos
temp := typecheck.TempAt(pos.WithNotStmt(), s.curfn, t)
temp.SetOpenDeferSlot(true)
var addrTemp *ssa.Value
// Use OpVarLive to make sure stack slot for the closure is not removed by
// dead-store elimination
if s.curBlock.ID != s.f.Entry.ID {
// Force the argtmp storing this defer function/receiver/arg to be
// declared in the entry block, so that it will be live for the
// defer exit code (which will actually access it only if the
// associated defer call has been activated).
s.defvars[s.f.Entry.ID][memVar] = s.f.Entry.NewValue1A(src.NoXPos, ssa.OpVarDef, types.TypeMem, argTemp, s.defvars[s.f.Entry.ID][memVar])
s.defvars[s.f.Entry.ID][memVar] = s.f.Entry.NewValue1A(src.NoXPos, ssa.OpVarLive, types.TypeMem, argTemp, s.defvars[s.f.Entry.ID][memVar])
addrArgTemp = s.f.Entry.NewValue2A(src.NoXPos, ssa.OpLocalAddr, types.NewPtr(argTemp.Type()), argTemp, s.sp, s.defvars[s.f.Entry.ID][memVar])
// Force the tmp storing this defer function to be declared in the entry
// block, so that it will be live for the defer exit code (which will
// actually access it only if the associated defer call has been activated).
s.defvars[s.f.Entry.ID][memVar] = s.f.Entry.NewValue1A(src.NoXPos, ssa.OpVarDef, types.TypeMem, temp, s.defvars[s.f.Entry.ID][memVar])
s.defvars[s.f.Entry.ID][memVar] = s.f.Entry.NewValue1A(src.NoXPos, ssa.OpVarLive, types.TypeMem, temp, s.defvars[s.f.Entry.ID][memVar])
addrTemp = s.f.Entry.NewValue2A(src.NoXPos, ssa.OpLocalAddr, types.NewPtr(temp.Type()), temp, s.sp, s.defvars[s.f.Entry.ID][memVar])
} else {
// Special case if we're still in the entry block. We can't use
// the above code, since s.defvars[s.f.Entry.ID] isn't defined
// until we end the entry block with s.endBlock().
s.vars[memVar] = s.newValue1Apos(ssa.OpVarDef, types.TypeMem, argTemp, s.mem(), false)
s.vars[memVar] = s.newValue1Apos(ssa.OpVarLive, types.TypeMem, argTemp, s.mem(), false)
addrArgTemp = s.newValue2Apos(ssa.OpLocalAddr, types.NewPtr(argTemp.Type()), argTemp, s.sp, s.mem(), false)
}
if t.HasPointers() {
// Since we may use this argTemp during exit depending on the
// deferBits, we must define it unconditionally on entry.
// Therefore, we must make sure it is zeroed out in the entry
// block if it contains pointers, else GC may wrongly follow an
// uninitialized pointer value.
argTemp.SetNeedzero(true)
}
if !canSSA {
a := s.addr(n)
s.move(t, addrArgTemp, a)
return addrArgTemp
s.vars[memVar] = s.newValue1Apos(ssa.OpVarDef, types.TypeMem, temp, s.mem(), false)
s.vars[memVar] = s.newValue1Apos(ssa.OpVarLive, types.TypeMem, temp, s.mem(), false)
addrTemp = s.newValue2Apos(ssa.OpLocalAddr, types.NewPtr(temp.Type()), temp, s.sp, s.mem(), false)
}
// Since we may use this temp during exit depending on the
// deferBits, we must define it unconditionally on entry.
// Therefore, we must make sure it is zeroed out in the entry
// block if it contains pointers, else GC may wrongly follow an
// uninitialized pointer value.
temp.SetNeedzero(true)
// We are storing to the stack, hence we can avoid the full checks in
// storeType() (no write barrier) and do a simple store().
s.store(t, addrArgTemp, val)
return addrArgTemp
s.store(t, addrTemp, val)
return addrTemp
}
// openDeferExit generates SSA for processing all the open coded defers at exit.