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[dev.regabi] cmd/compile: move more PAUTOHEAP to SSA construction

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This CL moves almost all PAUTOHEAP handling code to SSA construction.
Instead of changing Names to PAUTOHEAP, escape analysis now only sets
n.Esc() to ir.EscHeap, and SSA handles creating the "&x"
pseudo-variables and associating them via Heapaddr.

This CL also gets rid of n.Stackcopy, which was used to distinguish
the heap copy of a parameter used within a function from the stack
copy used in the function calling convention. In practice, this is
always obvious from context: liveness and function prologue/epilogue
want to know about the stack copies, and everywhere else wants the
heap copy.

Hopefully moving all parameter/result handling into SSA helps with
making the register ABI stuff easier.

Also, the only remaining uses of PAUTOHEAP are now for closure
variables, so I intend to rename it to PCLOSUREVAR or get rid of those
altogether too. But this CL is already big and scary enough.

Change-Id: Ief5ef6205041b9d0ee445314310c0c5a98187e77
Reviewed-on: https://go-review.googlesource.com/c/go/+/283233
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Trust: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: David Chase <drchase@google.com>
This commit is contained in:
Matthew Dempsky 2021-01-11 22:58:23 -08:00
parent 4476300425
commit f97983249a
12 changed files with 192 additions and 424 deletions
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16
src/cmd/compile/internal/dwarfgen/dwarf.go
View file

@ -186,19 +186,11 @@ func createDwarfVars(fnsym *obj.LSym, complexOK bool, fn *ir.Func, apDecls []*ir
isReturnValue := (n.Class == ir.PPARAMOUT)
if n.Class == ir.PPARAM || n.Class == ir.PPARAMOUT {
abbrev = dwarf.DW_ABRV_PARAM_LOCLIST
} else if n.Class == ir.PAUTOHEAP {
// If dcl in question has been promoted to heap, do a bit
// of extra work to recover original class (auto or param);
// see issue 30908. This insures that we get the proper
// signature in the abstract function DIE, but leaves a
// misleading location for the param (we want pointer-to-heap
// and not stack).
}
if n.Esc() == ir.EscHeap {
// The variable in question has been promoted to the heap.
// Its address is in n.Heapaddr.
// TODO(thanm): generate a better location expression
stackcopy := n.Stackcopy
if stackcopy != nil && (stackcopy.Class == ir.PPARAM || stackcopy.Class == ir.PPARAMOUT) {
abbrev = dwarf.DW_ABRV_PARAM_LOCLIST
isReturnValue = (stackcopy.Class == ir.PPARAMOUT)
}
}
inlIndex := 0
if base.Flag.GenDwarfInl > 1 {