cmd: move experiment flags into objabi.Experiment

This moves all remaining GOEXPERIMENT flags into the objabi.Experiment
struct, drops the "_enabled" from their name, and makes them all bool
typed.

We also drop DebugFlags.Fieldtrack because the previous CL shifted the
one test that used it to use GOEXPERIMENT instead.

Change-Id: I3406fe62b1c300bb4caeaffa6ca5ce56a70497fe
Reviewed-on: https://go-review.googlesource.com/c/go/+/302389
Trust: Austin Clements <austin@google.com>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

13 files changed, 29 insertions, 34 deletions

diff --git a/src/cmd/compile/internal/base/debug.go b/src/cmd/compile/internal/base/debug.go
index b9fa3d882e..7590dc1bfa 100644
--- a/src/cmd/compile/internal/base/debug.go
+++ b/src/cmd/compile/internal/base/debug.go
@@ -13,14 +13,10 @@ import (
 	"reflect"
 	"strconv"
 	"strings"
-
-	"cmd/internal/objabi"
 )
 
 // Debug holds the parsed debugging configuration values.
-var Debug = DebugFlags{
-	Fieldtrack: &objabi.Fieldtrack_enabled,
-}
+var Debug DebugFlags
 
 // DebugFlags defines the debugging configuration values (see var Debug).
 // Each struct field is a different value, named for the lower-case of the field name.
@@ -38,7 +34,6 @@ type DebugFlags struct {
 	DumpPtrs             int    `help:"show Node pointers values in dump output"`
 	DwarfInl             int    `help:"print information about DWARF inlined function creation"`
 	Export               int    `help:"print export data"`
-	Fieldtrack           *int   `help:"enable field tracking"`
 	GCProg               int    `help:"print dump of GC programs"`
 	InlFuncsWithClosures int    `help:"allow functions with closures to be inlined"`
 	Libfuzzer            int    `help:"enable coverage instrumentation for libfuzzer"`
@@ -86,8 +81,6 @@ func init() {
 			panic(fmt.Sprintf("base.Debug.%s has invalid type %v (must be int or string)", f.Name, f.Type))
 		case *int, *string:
 			// ok
-		case **int:
-			ptr = *ptr.(**int) // record the *int itself
 		}
 		debugTab = append(debugTab, debugField{name, help, ptr})
 	}
diff --git a/src/cmd/compile/internal/base/flag.go b/src/cmd/compile/internal/base/flag.go
index 959fededa9..751ab1b5c7 100644
--- a/src/cmd/compile/internal/base/flag.go
+++ b/src/cmd/compile/internal/base/flag.go
@@ -339,7 +339,7 @@ func concurrentBackendAllowed() bool {
 		return false
 	}
 	// TODO: Test and delete this condition.
-	if objabi.Fieldtrack_enabled != 0 {
+	if objabi.Experiment.FieldTrack {
 		return false
 	}
 	// TODO: fix races and enable the following flags
diff --git a/src/cmd/compile/internal/dwarfgen/dwarf.go b/src/cmd/compile/internal/dwarfgen/dwarf.go
index 53752097ed..7b5863bbc6 100644
--- a/src/cmd/compile/internal/dwarfgen/dwarf.go
+++ b/src/cmd/compile/internal/dwarfgen/dwarf.go
@@ -278,7 +278,7 @@ func createSimpleVar(fnsym *obj.LSym, n *ir.Name) *dwarf.Var {
 		if base.Ctxt.FixedFrameSize() == 0 {
 			offs -= int64(types.PtrSize)
 		}
-		if objabi.Framepointer_enabled {
+		if objabi.FramePointerEnabled {
 			offs -= int64(types.PtrSize)
 		}
 
diff --git a/src/cmd/compile/internal/noder/lex.go b/src/cmd/compile/internal/noder/lex.go
index 36cfb9bc23..60b724d154 100644
--- a/src/cmd/compile/internal/noder/lex.go
+++ b/src/cmd/compile/internal/noder/lex.go
@@ -44,7 +44,7 @@ func pragmaFlag(verb string) ir.PragmaFlag {
 	case "go:build":
 		return ir.GoBuildPragma
 	case "go:nointerface":
-		if objabi.Fieldtrack_enabled != 0 {
+		if objabi.Experiment.FieldTrack {
 			return ir.Nointerface
 		}
 	case "go:noescape":
diff --git a/src/cmd/compile/internal/ssa/compile.go b/src/cmd/compile/internal/ssa/compile.go
index c267274366..b1bcd4566e 100644
--- a/src/cmd/compile/internal/ssa/compile.go
+++ b/src/cmd/compile/internal/ssa/compile.go
@@ -454,7 +454,7 @@ var passes = [...]pass{
 	{name: "dse", fn: dse},
 	{name: "writebarrier", fn: writebarrier, required: true}, // expand write barrier ops
 	{name: "insert resched checks", fn: insertLoopReschedChecks,
-		disabled: objabi.Preemptibleloops_enabled == 0}, // insert resched checks in loops.
+		disabled: !objabi.Experiment.PreemptibleLoops}, // insert resched checks in loops.
 	{name: "lower", fn: lower, required: true},
 	{name: "addressing modes", fn: addressingModes, required: false},
 	{name: "lowered deadcode for cse", fn: deadcode}, // deadcode immediately before CSE avoids CSE making dead values live again
diff --git a/src/cmd/compile/internal/ssa/regalloc.go b/src/cmd/compile/internal/ssa/regalloc.go
index 18908681df..42df8387e4 100644
--- a/src/cmd/compile/internal/ssa/regalloc.go
+++ b/src/cmd/compile/internal/ssa/regalloc.go
@@ -594,7 +594,7 @@ func (s *regAllocState) init(f *Func) {
 	if s.f.Config.hasGReg {
 		s.allocatable &^= 1 << s.GReg
 	}
-	if objabi.Framepointer_enabled && s.f.Config.FPReg >= 0 {
+	if objabi.FramePointerEnabled && s.f.Config.FPReg >= 0 {
 		s.allocatable &^= 1 << uint(s.f.Config.FPReg)
 	}
 	if s.f.Config.LinkReg != -1 {
diff --git a/src/cmd/compile/internal/ssagen/pgen.go b/src/cmd/compile/internal/ssagen/pgen.go
index 0088f10fa8..0cb506fb74 100644
--- a/src/cmd/compile/internal/ssagen/pgen.go
+++ b/src/cmd/compile/internal/ssagen/pgen.go
@@ -202,7 +202,7 @@ func StackOffset(slot ssa.LocalSlot) int32 {
 		if base.Ctxt.FixedFrameSize() == 0 {
 			off -= int64(types.PtrSize)
 		}
-		if objabi.Framepointer_enabled {
+		if objabi.FramePointerEnabled {
 			off -= int64(types.PtrSize)
 		}
 	}
@@ -215,7 +215,7 @@ func fieldtrack(fnsym *obj.LSym, tracked map[*obj.LSym]struct{}) {
 	if fnsym == nil {
 		return
 	}
-	if objabi.Fieldtrack_enabled == 0 || len(tracked) == 0 {
+	if !objabi.Experiment.FieldTrack || len(tracked) == 0 {
 		return
 	}
 
diff --git a/src/cmd/compile/internal/walk/expr.go b/src/cmd/compile/internal/walk/expr.go
index 1d90029298..4cc5b65d3e 100644
--- a/src/cmd/compile/internal/walk/expr.go
+++ b/src/cmd/compile/internal/walk/expr.go
@@ -931,7 +931,7 @@ func usemethod(n *ir.CallExpr) {
 }
 
 func usefield(n *ir.SelectorExpr) {
-	if objabi.Fieldtrack_enabled == 0 {
+	if !objabi.Experiment.FieldTrack {
 		return
 	}
 
diff --git a/src/cmd/go/internal/work/gc.go b/src/cmd/go/internal/work/gc.go
index 0fb6156c5a..95fffeabd6 100644
--- a/src/cmd/go/internal/work/gc.go
+++ b/src/cmd/go/internal/work/gc.go
@@ -223,7 +223,7 @@ CheckFlags:
 	}
 
 	// TODO: Test and delete these conditions.
-	if objabi.Fieldtrack_enabled != 0 || objabi.Preemptibleloops_enabled != 0 {
+	if objabi.Experiment.FieldTrack || objabi.Experiment.PreemptibleLoops {
 		canDashC = false
 	}
 
diff --git a/src/cmd/internal/objabi/util.go b/src/cmd/internal/objabi/util.go
index 548e9d0a30..9fbe6490e0 100644
--- a/src/cmd/internal/objabi/util.go
+++ b/src/cmd/internal/objabi/util.go
@@ -174,8 +174,14 @@ func init() {
 	GOEXPERIMENT = expList()
 }
 
+// FramePointerEnabled enables the use of platform conventions for
+// saving frame pointers.
+//
+// This used to be an experiment, but now it's always enabled on
+// platforms that support it.
+//
 // Note: must agree with runtime.framepointer_enabled.
-var Framepointer_enabled = GOARCH == "amd64" || GOARCH == "arm64"
+var FramePointerEnabled = GOARCH == "amd64" || GOARCH == "arm64"
 
 func addexp(s string) {
 	// Could do general integer parsing here, but the runtime.haveexperiment doesn't yet.
@@ -203,18 +209,14 @@ func addexp(s string) {
 	os.Exit(2)
 }
 
-var (
-	Fieldtrack_enabled        int
-	Preemptibleloops_enabled  int
-	Staticlockranking_enabled int
-)
-
 // Experiment contains flags for GOEXPERIMENTs.
-//
-// TODO(austin): Move the package-level experiment flags into this.
-var Experiment ExpFlags
+var Experiment = ExpFlags{}
 
 type ExpFlags struct {
+	FieldTrack        bool
+	PreemptibleLoops  bool
+	StaticLockRanking bool
+
 	// regabi is split into several sub-experiments that can be
 	// enabled individually. GOEXPERIMENT=regabi implies the
 	// subset that are currently "working". Not all combinations work.
@@ -250,9 +252,9 @@ var exper = []struct {
 	name string
 	val  interface{} // Must be *int or *bool
 }{
-	{"fieldtrack", &Fieldtrack_enabled},
-	{"preemptibleloops", &Preemptibleloops_enabled},
-	{"staticlockranking", &Staticlockranking_enabled},
+	{"fieldtrack", &Experiment.FieldTrack},
+	{"preemptibleloops", &Experiment.PreemptibleLoops},
+	{"staticlockranking", &Experiment.StaticLockRanking},
 	{"regabi", &Experiment.regabi},
 	{"regabiwrappers", &Experiment.RegabiWrappers},
 	{"regabig", &Experiment.RegabiG},
diff --git a/src/cmd/link/internal/ld/deadcode.go b/src/cmd/link/internal/ld/deadcode.go
index a52652566b..33468b429c 100644
--- a/src/cmd/link/internal/ld/deadcode.go
+++ b/src/cmd/link/internal/ld/deadcode.go
@@ -32,7 +32,7 @@ type deadcodePass struct {
 func (d *deadcodePass) init() {
 	d.ldr.InitReachable()
 	d.ifaceMethod = make(map[methodsig]bool)
-	if objabi.Fieldtrack_enabled != 0 {
+	if objabi.Experiment.FieldTrack {
 		d.ldr.Reachparent = make([]loader.Sym, d.ldr.NSym())
 	}
 	d.dynlink = d.ctxt.DynlinkingGo()
@@ -255,7 +255,7 @@ func (d *deadcodePass) mark(symIdx, parent loader.Sym) {
 	if symIdx != 0 && !d.ldr.AttrReachable(symIdx) {
 		d.wq.push(symIdx)
 		d.ldr.SetAttrReachable(symIdx, true)
-		if objabi.Fieldtrack_enabled != 0 && d.ldr.Reachparent[symIdx] == 0 {
+		if objabi.Experiment.FieldTrack && d.ldr.Reachparent[symIdx] == 0 {
 			d.ldr.Reachparent[symIdx] = parent
 		}
 		if *flagDumpDep {
diff --git a/src/cmd/link/internal/ld/main.go b/src/cmd/link/internal/ld/main.go
index 3c5355df9c..78df50ee2d 100644
--- a/src/cmd/link/internal/ld/main.go
+++ b/src/cmd/link/internal/ld/main.go
@@ -251,7 +251,7 @@ func Main(arch *sys.Arch, theArch Arch) {
 
 	bench.Start("dostrdata")
 	ctxt.dostrdata()
-	if objabi.Fieldtrack_enabled != 0 {
+	if objabi.Experiment.FieldTrack {
 		bench.Start("fieldtrack")
 		fieldtrack(ctxt.Arch, ctxt.loader)
 	}
diff --git a/src/runtime/runtime2.go b/src/runtime/runtime2.go
index f5318e6f11..e5f948ec86 100644
--- a/src/runtime/runtime2.go
+++ b/src/runtime/runtime2.go
@@ -1105,5 +1105,5 @@ var (
 	isarchive bool // -buildmode=c-archive
 )
 
-// Must agree with cmd/internal/objabi.Framepointer_enabled.
+// Must agree with cmd/internal/objabi.Experiment.FramePointer.
 const framepointer_enabled = GOARCH == "amd64" || GOARCH == "arm64"