[dev.regabi] cmd/compile: group known symbols, packages, names [generated]

[dev.regabi] cmd/compile: group known symbols, packages, names [generated]

There are a handful of pre-computed magic symbols known by
package gc, and we need a place to store them.

If we keep them together, the need for type *ir.Name means that
package ir is the lowest package in the import hierarchy that they
can go in. And package ir needs gopkg for methodSymSuffix
(in a later CL), so they can't go any higher either, at least not all together.
So package ir it is.

Rather than dump them all into the top-level package ir
namespace, however, we introduce global structs, Syms, Pkgs, and Names,
and make the known symbols, packages, and names fields of those.

[git-generate]
cd src/cmd/compile/internal/gc

rf '
	add go.go:$ \
		// Names holds known names. \
		var Names struct{} \
		\
		// Syms holds known symbols. \
		var Syms struct {} \
		\
		// Pkgs holds known packages. \
		var Pkgs struct {} \

	mv staticuint64s Names.Staticuint64s
	mv zerobase Names.Zerobase

	mv assertE2I Syms.AssertE2I
	mv assertE2I2 Syms.AssertE2I2
	mv assertI2I Syms.AssertI2I
	mv assertI2I2 Syms.AssertI2I2
	mv deferproc Syms.Deferproc
	mv deferprocStack Syms.DeferprocStack
	mv Deferreturn Syms.Deferreturn
	mv Duffcopy Syms.Duffcopy
	mv Duffzero Syms.Duffzero
	mv gcWriteBarrier Syms.GCWriteBarrier
	mv goschedguarded Syms.Goschedguarded
	mv growslice Syms.Growslice
	mv msanread Syms.Msanread
	mv msanwrite Syms.Msanwrite
	mv msanmove Syms.Msanmove
	mv newobject Syms.Newobject
	mv newproc Syms.Newproc
	mv panicdivide Syms.Panicdivide
	mv panicshift Syms.Panicshift
	mv panicdottypeE Syms.PanicdottypeE
	mv panicdottypeI Syms.PanicdottypeI
	mv panicnildottype Syms.Panicnildottype
	mv panicoverflow Syms.Panicoverflow
	mv raceread Syms.Raceread
	mv racereadrange Syms.Racereadrange
	mv racewrite Syms.Racewrite
	mv racewriterange Syms.Racewriterange
	mv SigPanic Syms.SigPanic
	mv typedmemclr Syms.Typedmemclr
	mv typedmemmove Syms.Typedmemmove
	mv Udiv Syms.Udiv
	mv writeBarrier Syms.WriteBarrier
	mv zerobaseSym Syms.Zerobase
	mv arm64HasATOMICS Syms.ARM64HasATOMICS
	mv armHasVFPv4 Syms.ARMHasVFPv4
	mv x86HasFMA Syms.X86HasFMA
	mv x86HasPOPCNT Syms.X86HasPOPCNT
	mv x86HasSSE41 Syms.X86HasSSE41
	mv WasmDiv Syms.WasmDiv
	mv WasmMove Syms.WasmMove
	mv WasmZero Syms.WasmZero
	mv WasmTruncS Syms.WasmTruncS
	mv WasmTruncU Syms.WasmTruncU

	mv gopkg Pkgs.Go
	mv itabpkg Pkgs.Itab
	mv itablinkpkg Pkgs.Itablink
	mv mappkg Pkgs.Map
	mv msanpkg Pkgs.Msan
	mv racepkg Pkgs.Race
	mv Runtimepkg Pkgs.Runtime
	mv trackpkg Pkgs.Track
	mv unsafepkg Pkgs.Unsafe

	mv Names Syms Pkgs symtab.go
	mv symtab.go cmd/compile/internal/ir
'

Change-Id: Ic143862148569a3bcde8e70b26d75421aa2d00f3
Reviewed-on: https://go-review.googlesource.com/c/go/+/279235
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>