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[dev.regabi] cmd/compile: use LinksymOffsetExpr in walkConvInterface

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This CL updates walkConvInterface to use LinksymOffsetExpr for
referencing runtime.staticuint64s and runtime.zerobase.

Passes toolstash -cmp (surprisingly).

Change-Id: Iad7e30371f89c8a5e176b5ddbc53faf57012ba0d
Reviewed-on: https://go-review.googlesource.com/c/go/+/284229
Trust: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
This commit is contained in:
Matthew Dempsky 2021-01-17 01:13:34 -08:00
parent 87845d14f9
commit 99a5db11ac
4 changed files with 14 additions and 19 deletions
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7
src/cmd/compile/internal/ir/expr.go
View File

@ -477,6 +477,13 @@ func NewLinksymOffsetExpr(pos src.XPos, lsym *obj.LSym, offset int64, typ *types
return n
}
// NewLinksymExpr is NewLinksymOffsetExpr, but with offset fixed at 0.
func NewLinksymExpr(pos src.XPos, lsym *obj.LSym, typ *types.Type) *LinksymOffsetExpr {
return NewLinksymOffsetExpr(pos, lsym, 0, typ)
}
// NewNameOffsetExpr is NewLinksymOffsetExpr, but taking a *Name
// representing a global variable instead of an *obj.LSym directly.
func NewNameOffsetExpr(pos src.XPos, name *Name, offset int64, typ *types.Type) *LinksymOffsetExpr {
if name == nil || IsBlank(name) || !(name.Op() == ONAME && name.Class == PEXTERN) {
base.FatalfAt(pos, "cannot take offset of nil, blank name or non-global variable: %v", name)

7
src/cmd/compile/internal/ir/symtab.go
View File

@ -9,12 +9,6 @@ import (
"cmd/internal/obj"
)
// Names holds known names.
var Names struct {
Staticuint64s *Name
Zerobase *Name
}
// Syms holds known symbols.
var Syms struct {
AssertE2I *obj.LSym
@ -46,6 +40,7 @@ var Syms struct {
Racewriterange *obj.LSym
// Wasm
SigPanic *obj.LSym
Staticuint64s *obj.LSym
Typedmemclr *obj.LSym
Typedmemmove *obj.LSym
Udiv *obj.LSym

1
src/cmd/compile/internal/ssagen/ssa.go
View File

@ -124,6 +124,7 @@ func InitConfig() {
ir.Syms.X86HasFMA = typecheck.LookupRuntimeVar("x86HasFMA") // bool
ir.Syms.ARMHasVFPv4 = typecheck.LookupRuntimeVar("armHasVFPv4") // bool
ir.Syms.ARM64HasATOMICS = typecheck.LookupRuntimeVar("arm64HasATOMICS") // bool
ir.Syms.Staticuint64s = typecheck.LookupRuntimeVar("staticuint64s")
ir.Syms.Typedmemclr = typecheck.LookupRuntimeFunc("typedmemclr")
ir.Syms.Typedmemmove = typecheck.LookupRuntimeFunc("typedmemmove")
ir.Syms.Udiv = typecheck.LookupRuntimeVar("udiv") // asm func with special ABI

18
src/cmd/compile/internal/walk/convert.go
View File

@ -66,17 +66,6 @@ func walkConvInterface(n *ir.ConvExpr, init *ir.Nodes) ir.Node {
return l
}
if ir.Names.Staticuint64s == nil {
ir.Names.Staticuint64s = typecheck.NewName(ir.Pkgs.Runtime.Lookup("staticuint64s"))
ir.Names.Staticuint64s.Class = ir.PEXTERN
// The actual type is [256]uint64, but we use [256*8]uint8 so we can address
// individual bytes.
ir.Names.Staticuint64s.SetType(types.NewArray(types.Types[types.TUINT8], 256*8))
ir.Names.Zerobase = typecheck.NewName(ir.Pkgs.Runtime.Lookup("zerobase"))
ir.Names.Zerobase.Class = ir.PEXTERN
ir.Names.Zerobase.SetType(types.Types[types.TUINTPTR])
}
// Optimize convT2{E,I} for many cases in which T is not pointer-shaped,
// by using an existing addressable value identical to n.Left
// or creating one on the stack.
@ -85,7 +74,7 @@ func walkConvInterface(n *ir.ConvExpr, init *ir.Nodes) ir.Node {
case fromType.Size() == 0:
// n.Left is zero-sized. Use zerobase.
cheapExpr(n.X, init) // Evaluate n.Left for side-effects. See issue 19246.
value = ir.Names.Zerobase
value = ir.NewLinksymExpr(base.Pos, ir.Syms.Zerobase, types.Types[types.TUINTPTR])
case fromType.IsBoolean() || (fromType.Size() == 1 && fromType.IsInteger()):
// n.Left is a bool/byte. Use staticuint64s[n.Left * 8] on little-endian
// and staticuint64s[n.Left * 8 + 7] on big-endian.
@ -95,7 +84,10 @@ func walkConvInterface(n *ir.ConvExpr, init *ir.Nodes) ir.Node {
if ssagen.Arch.LinkArch.ByteOrder == binary.BigEndian {
index = ir.NewBinaryExpr(base.Pos, ir.OADD, index, ir.NewInt(7))
}
xe := ir.NewIndexExpr(base.Pos, ir.Names.Staticuint64s, index)
// The actual type is [256]uint64, but we use [256*8]uint8 so we can address
// individual bytes.
staticuint64s := ir.NewLinksymExpr(base.Pos, ir.Syms.Staticuint64s, types.NewArray(types.Types[types.TUINT8], 256*8))
xe := ir.NewIndexExpr(base.Pos, staticuint64s, index)
xe.SetBounded(true)
value = xe
case n.X.Op() == ir.ONAME && n.X.(*ir.Name).Class == ir.PEXTERN && n.X.(*ir.Name).Readonly():