[dev.regabi] cmd/compile: clean up debug flag (-d) handling [generated]

The debug table is not as haphazard as flags, but there are still
a few mismatches between command-line names and variable names.
This CL moves them all into a consistent home (var Debug, like var Flag).

Code updated automatically using the rf command below.
A followup CL will make a few manual cleanups, leaving this CL
completely automated and easier to regenerate during merge
conflicts.

[git-generate]
cd src/cmd/compile/internal/gc
rf '
	add main.go var Debug struct{}
	mv Debug_append Debug.Append
	mv Debug_checkptr Debug.Checkptr
	mv Debug_closure Debug.Closure
	mv Debug_compilelater Debug.CompileLater
	mv disable_checknil Debug.DisableNil
	mv debug_dclstack Debug.DclStack
	mv Debug_gcprog Debug.GCProg
	mv Debug_libfuzzer Debug.Libfuzzer
	mv Debug_checknil Debug.Nil
	mv Debug_panic Debug.Panic
	mv Debug_slice Debug.Slice
	mv Debug_typeassert Debug.TypeAssert
	mv Debug_wb Debug.WB
	mv Debug_export Debug.Export
	mv Debug_pctab Debug.PCTab
	mv Debug_locationlist Debug.LocationLists
	mv Debug_typecheckinl Debug.TypecheckInl
	mv Debug_gendwarfinl Debug.DwarfInl
	mv Debug_softfloat Debug.SoftFloat
	mv Debug_defer Debug.Defer
	mv Debug_dumpptrs Debug.DumpPtrs

	mv flag.go:/parse.-d/-1,/unknown.debug/+2 parseDebug

	mv debugtab Debug parseDebug \
		debugHelpHeader debugHelpFooter \
		debug.go

	# Remove //go:generate line copied from main.go
	rm debug.go:/go:generate/-+
'

Change-Id: I625761ca5659be4052f7161a83baa00df75cca91
Reviewed-on: https://go-review.googlesource.com/c/go/+/272246
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

29 files changed, 226 insertions, 213 deletions

diff --git a/src/cmd/compile/internal/amd64/ssa.go b/src/cmd/compile/internal/amd64/ssa.go
index 5ff05a0edd..1f2d626721 100644
--- a/src/cmd/compile/internal/amd64/ssa.go
+++ b/src/cmd/compile/internal/amd64/ssa.go
@@ -1164,7 +1164,7 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 		if logopt.Enabled() {
 			logopt.LogOpt(v.Pos, "nilcheck", "genssa", v.Block.Func.Name)
 		}
-		if gc.Debug_checknil != 0 && v.Pos.Line() > 1 { // v.Pos.Line()==1 in generated wrappers
+		if gc.Debug.Nil != 0 && v.Pos.Line() > 1 { // v.Pos.Line()==1 in generated wrappers
 			gc.Warnl(v.Pos, "generated nil check")
 		}
 	case ssa.OpAMD64MOVBatomicload, ssa.OpAMD64MOVLatomicload, ssa.OpAMD64MOVQatomicload:
diff --git a/src/cmd/compile/internal/arm/ssa.go b/src/cmd/compile/internal/arm/ssa.go
index 765a771546..82a5172ec7 100644
--- a/src/cmd/compile/internal/arm/ssa.go
+++ b/src/cmd/compile/internal/arm/ssa.go
@@ -741,7 +741,7 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 		if logopt.Enabled() {
 			logopt.LogOpt(v.Pos, "nilcheck", "genssa", v.Block.Func.Name)
 		}
-		if gc.Debug_checknil != 0 && v.Pos.Line() > 1 { // v.Pos.Line()==1 in generated wrappers
+		if gc.Debug.Nil != 0 && v.Pos.Line() > 1 { // v.Pos.Line()==1 in generated wrappers
 			gc.Warnl(v.Pos, "generated nil check")
 		}
 	case ssa.OpARMLoweredZero:
diff --git a/src/cmd/compile/internal/arm64/ssa.go b/src/cmd/compile/internal/arm64/ssa.go
index 22b28a9308..dcbd8f9474 100644
--- a/src/cmd/compile/internal/arm64/ssa.go
+++ b/src/cmd/compile/internal/arm64/ssa.go
@@ -1038,7 +1038,7 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 		if logopt.Enabled() {
 			logopt.LogOpt(v.Pos, "nilcheck", "genssa", v.Block.Func.Name)
 		}
-		if gc.Debug_checknil != 0 && v.Pos.Line() > 1 { // v.Line==1 in generated wrappers
+		if gc.Debug.Nil != 0 && v.Pos.Line() > 1 { // v.Line==1 in generated wrappers
 			gc.Warnl(v.Pos, "generated nil check")
 		}
 	case ssa.OpARM64Equal,
diff --git a/src/cmd/compile/internal/gc/alg.go b/src/cmd/compile/internal/gc/alg.go
index c1d8de6bad..87b905ed59 100644
--- a/src/cmd/compile/internal/gc/alg.go
+++ b/src/cmd/compile/internal/gc/alg.go
@@ -387,7 +387,7 @@ func genhash(t *types.Type) *obj.LSym {
 	typecheckslice(fn.Nbody.Slice(), ctxStmt)
 	Curfn = nil
 
-	if debug_dclstack != 0 {
+	if Debug.DclStack != 0 {
 		testdclstack()
 	}
 
@@ -766,7 +766,7 @@ func geneq(t *types.Type) *obj.LSym {
 	typecheckslice(fn.Nbody.Slice(), ctxStmt)
 	Curfn = nil
 
-	if debug_dclstack != 0 {
+	if Debug.DclStack != 0 {
 		testdclstack()
 	}
 
diff --git a/src/cmd/compile/internal/gc/closure.go b/src/cmd/compile/internal/gc/closure.go
index f850cbe280..c25a446999 100644
--- a/src/cmd/compile/internal/gc/closure.go
+++ b/src/cmd/compile/internal/gc/closure.go
@@ -337,7 +337,7 @@ func hasemptycvars(clo *Node) bool {
 // closuredebugruntimecheck applies boilerplate checks for debug flags
 // and compiling runtime
 func closuredebugruntimecheck(clo *Node) {
-	if Debug_closure > 0 {
+	if Debug.Closure > 0 {
 		if clo.Esc == EscHeap {
 			Warnl(clo.Pos, "heap closure, captured vars = %v", clo.Func.ClosureVars)
 		} else {
@@ -386,7 +386,7 @@ func walkclosure(clo *Node, init *Nodes) *Node {
 
 	// If no closure vars, don't bother wrapping.
 	if hasemptycvars(clo) {
-		if Debug_closure > 0 {
+		if Debug.Closure > 0 {
 			Warnl(clo.Pos, "closure converted to global")
 		}
 		return fn.Nname
diff --git a/src/cmd/compile/internal/gc/debug.go b/src/cmd/compile/internal/gc/debug.go
new file mode 100644
index 0000000000..f6be3d57b0
--- /dev/null
+++ b/src/cmd/compile/internal/gc/debug.go
@@ -0,0 +1,167 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package gc
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"strconv"
+	"strings"
+
+	"cmd/compile/internal/ssa"
+	"cmd/internal/objabi"
+)
+
+// Debug arguments.
+// These can be specified with the -d flag, as in "-d nil"
+// to set the debug_checknil variable.
+// Multiple options can be comma-separated.
+// Each option accepts an optional argument, as in "gcprog=2"
+var debugtab = []struct {
+	name string
+	help string
+	val  interface{} // must be *int or *string
+}{
+	{"append", "print information about append compilation", &Debug.Append},
+	{"checkptr", "instrument unsafe pointer conversions", &Debug.Checkptr},
+	{"closure", "print information about closure compilation", &Debug.Closure},
+	{"compilelater", "compile functions as late as possible", &Debug.CompileLater},
+	{"disablenil", "disable nil checks", &Debug.DisableNil},
+	{"dclstack", "run internal dclstack check", &Debug.DclStack},
+	{"dumpptrs", "show Node pointer values in Dump/dumplist output", &Debug.DumpPtrs},
+	{"gcprog", "print dump of GC programs", &Debug.GCProg},
+	{"libfuzzer", "coverage instrumentation for libfuzzer", &Debug.Libfuzzer},
+	{"nil", "print information about nil checks", &Debug.Nil},
+	{"panic", "do not hide any compiler panic", &Debug.Panic},
+	{"slice", "print information about slice compilation", &Debug.Slice},
+	{"typeassert", "print information about type assertion inlining", &Debug.TypeAssert},
+	{"wb", "print information about write barriers", &Debug.WB},
+	{"export", "print export data", &Debug.Export},
+	{"pctab", "print named pc-value table", &Debug.PCTab},
+	{"locationlists", "print information about DWARF location list creation", &Debug.LocationLists},
+	{"typecheckinl", "eager typechecking of inline function bodies", &Debug.TypecheckInl},
+	{"dwarfinl", "print information about DWARF inlined function creation", &Debug.DwarfInl},
+	{"softfloat", "force compiler to emit soft-float code", &Debug.SoftFloat},
+	{"defer", "print information about defer compilation", &Debug.Defer},
+	{"fieldtrack", "enable fieldtracking", &objabi.Fieldtrack_enabled},
+}
+
+var Debug struct {
+	Append        int
+	Checkptr      int
+	Closure       int
+	CompileLater  int
+	DisableNil    int
+	DclStack      int
+	GCProg        int
+	Libfuzzer     int
+	Nil           int
+	Panic         int
+	Slice         int
+	TypeAssert    int
+	WB            int
+	Export        int
+	PCTab         string
+	LocationLists int
+	TypecheckInl  int
+	DwarfInl      int
+	SoftFloat     int
+	Defer         int
+	DumpPtrs      int
+}
+
+func parseDebug() {
+	// parse -d argument
+	if Flag.LowerD != "" {
+	Split:
+		for _, name := range strings.Split(Flag.LowerD, ",") {
+			if name == "" {
+				continue
+			}
+			// display help about the -d option itself and quit
+			if name == "help" {
+				fmt.Print(debugHelpHeader)
+				maxLen := len("ssa/help")
+				for _, t := range debugtab {
+					if len(t.name) > maxLen {
+						maxLen = len(t.name)
+					}
+				}
+				for _, t := range debugtab {
+					fmt.Printf("\t%-*s\t%s\n", maxLen, t.name, t.help)
+				}
+				// ssa options have their own help
+				fmt.Printf("\t%-*s\t%s\n", maxLen, "ssa/help", "print help about SSA debugging")
+				fmt.Print(debugHelpFooter)
+				os.Exit(0)
+			}
+			val, valstring, haveInt := 1, "", true
+			if i := strings.IndexAny(name, "=:"); i >= 0 {
+				var err error
+				name, valstring = name[:i], name[i+1:]
+				val, err = strconv.Atoi(valstring)
+				if err != nil {
+					val, haveInt = 1, false
+				}
+			}
+			for _, t := range debugtab {
+				if t.name != name {
+					continue
+				}
+				switch vp := t.val.(type) {
+				case nil:
+					// Ignore
+				case *string:
+					*vp = valstring
+				case *int:
+					if !haveInt {
+						log.Fatalf("invalid debug value %v", name)
+					}
+					*vp = val
+				default:
+					panic("bad debugtab type")
+				}
+				continue Split
+			}
+			// special case for ssa for now
+			if strings.HasPrefix(name, "ssa/") {
+				// expect form ssa/phase/flag
+				// e.g. -d=ssa/generic_cse/time
+				// _ in phase name also matches space
+				phase := name[4:]
+				flag := "debug" // default flag is debug
+				if i := strings.Index(phase, "/"); i >= 0 {
+					flag = phase[i+1:]
+					phase = phase[:i]
+				}
+				err := ssa.PhaseOption(phase, flag, val, valstring)
+				if err != "" {
+					log.Fatalf(err)
+				}
+				continue Split
+			}
+			log.Fatalf("unknown debug key -d %s\n", name)
+		}
+	}
+}
+
+const debugHelpHeader = `usage: -d arg[,arg]* and arg is <key>[=<value>]
+
+<key> is one of:
+
+`
+
+const debugHelpFooter = `
+<value> is key-specific.
+
+Key "checkptr" supports values:
+	"0": instrumentation disabled
+	"1": conversions involving unsafe.Pointer are instrumented
+	"2": conversions to unsafe.Pointer force heap allocation
+
+Key "pctab" supports values:
+	"pctospadj", "pctofile", "pctoline", "pctoinline", "pctopcdata"
+`
diff --git a/src/cmd/compile/internal/gc/dwinl.go b/src/cmd/compile/internal/gc/dwinl.go
index 48d78f6cd7..edde7a4cc5 100644
--- a/src/cmd/compile/internal/gc/dwinl.go
+++ b/src/cmd/compile/internal/gc/dwinl.go
@@ -26,7 +26,7 @@ type varPos struct {
 func assembleInlines(fnsym *obj.LSym, dwVars []*dwarf.Var) dwarf.InlCalls {
 	var inlcalls dwarf.InlCalls
 
-	if Debug_gendwarfinl != 0 {
+	if Debug.DwarfInl != 0 {
 		Ctxt.Logf("assembling DWARF inlined routine info for %v\n", fnsym.Name)
 	}
 
@@ -181,7 +181,7 @@ func assembleInlines(fnsym *obj.LSym, dwVars []*dwarf.Var) dwarf.InlCalls {
 	}
 
 	// Debugging
-	if Debug_gendwarfinl != 0 {
+	if Debug.DwarfInl != 0 {
 		dumpInlCalls(inlcalls)
 		dumpInlVars(dwVars)
 	}
@@ -210,7 +210,7 @@ func genAbstractFunc(fn *obj.LSym) {
 		Ctxt.Diag("failed to locate precursor fn for %v", fn)
 		return
 	}
-	if Debug_gendwarfinl != 0 {
+	if Debug.DwarfInl != 0 {
 		Ctxt.Logf("DwarfAbstractFunc(%v)\n", fn.Name)
 	}
 	Ctxt.DwarfAbstractFunc(ifn, fn, Ctxt.Pkgpath)
diff --git a/src/cmd/compile/internal/gc/export.go b/src/cmd/compile/internal/gc/export.go
index edd2703238..48f77fa182 100644
--- a/src/cmd/compile/internal/gc/export.go
+++ b/src/cmd/compile/internal/gc/export.go
@@ -12,13 +12,9 @@ import (
 	"go/constant"
 )
 
-var (
-	Debug_export int // if set, print debugging information about export data
-)
-
 func exportf(bout *bio.Writer, format string, args ...interface{}) {
 	fmt.Fprintf(bout, format, args...)
-	if Debug_export != 0 {
+	if Debug.Export != 0 {
 		fmt.Printf(format, args...)
 	}
 }
@@ -71,7 +67,7 @@ func dumpexport(bout *bio.Writer) {
 	size := bout.Offset() - off
 	exportf(bout, "\n$$\n")
 
-	if Debug_export != 0 {
+	if Debug.Export != 0 {
 		fmt.Printf("BenchmarkExportSize:%s 1 %d bytes\n", Ctxt.Pkgpath, size)
 	}
 }
diff --git a/src/cmd/compile/internal/gc/flag.go b/src/cmd/compile/internal/gc/flag.go
index 090287ef62..06b0a88ba3 100644
--- a/src/cmd/compile/internal/gc/flag.go
+++ b/src/cmd/compile/internal/gc/flag.go
@@ -13,10 +13,9 @@ import (
 	"os"
 	"reflect"
 	"runtime"
-	"strconv"
+
 	"strings"
 
-	"cmd/compile/internal/ssa"
 	"cmd/internal/objabi"
 	"cmd/internal/sys"
 )
@@ -209,7 +208,7 @@ func ParseFlags() {
 	}
 	if Flag.Race || Flag.MSan {
 		// -race and -msan imply -d=checkptr for now.
-		Debug_checkptr = 1
+		Debug.Checkptr = 1
 	}
 
 	if Flag.CompilingRuntime && Flag.N != 0 {
@@ -222,89 +221,18 @@ func ParseFlags() {
 		log.Fatalf("cannot use concurrent backend compilation with provided flags; invoked as %v", os.Args)
 	}
 
-	// parse -d argument
-	if Flag.LowerD != "" {
-	Split:
-		for _, name := range strings.Split(Flag.LowerD, ",") {
-			if name == "" {
-				continue
-			}
-			// display help about the -d option itself and quit
-			if name == "help" {
-				fmt.Print(debugHelpHeader)
-				maxLen := len("ssa/help")
-				for _, t := range debugtab {
-					if len(t.name) > maxLen {
-						maxLen = len(t.name)
-					}
-				}
-				for _, t := range debugtab {
-					fmt.Printf("\t%-*s\t%s\n", maxLen, t.name, t.help)
-				}
-				// ssa options have their own help
-				fmt.Printf("\t%-*s\t%s\n", maxLen, "ssa/help", "print help about SSA debugging")
-				fmt.Print(debugHelpFooter)
-				os.Exit(0)
-			}
-			val, valstring, haveInt := 1, "", true
-			if i := strings.IndexAny(name, "=:"); i >= 0 {
-				var err error
-				name, valstring = name[:i], name[i+1:]
-				val, err = strconv.Atoi(valstring)
-				if err != nil {
-					val, haveInt = 1, false
-				}
-			}
-			for _, t := range debugtab {
-				if t.name != name {
-					continue
-				}
-				switch vp := t.val.(type) {
-				case nil:
-					// Ignore
-				case *string:
-					*vp = valstring
-				case *int:
-					if !haveInt {
-						log.Fatalf("invalid debug value %v", name)
-					}
-					*vp = val
-				default:
-					panic("bad debugtab type")
-				}
-				continue Split
-			}
-			// special case for ssa for now
-			if strings.HasPrefix(name, "ssa/") {
-				// expect form ssa/phase/flag
-				// e.g. -d=ssa/generic_cse/time
-				// _ in phase name also matches space
-				phase := name[4:]
-				flag := "debug" // default flag is debug
-				if i := strings.Index(phase, "/"); i >= 0 {
-					flag = phase[i+1:]
-					phase = phase[:i]
-				}
-				err := ssa.PhaseOption(phase, flag, val, valstring)
-				if err != "" {
-					log.Fatalf(err)
-				}
-				continue Split
-			}
-			log.Fatalf("unknown debug key -d %s\n", name)
-		}
-	}
+	parseDebug()
 
 	if Flag.CompilingRuntime {
 		// Runtime can't use -d=checkptr, at least not yet.
-		Debug_checkptr = 0
+		Debug.Checkptr = 0
 
 		// Fuzzing the runtime isn't interesting either.
-		Debug_libfuzzer = 0
+		Debug.Libfuzzer = 0
 	}
 
 	// set via a -d flag
-	Ctxt.Debugpcln = Debug_pctab
+	Ctxt.Debugpcln = Debug.PCTab
 }
 
 // registerFlags adds flag registrations for all the fields in Flag.
diff --git a/src/cmd/compile/internal/gc/fmt.go b/src/cmd/compile/internal/gc/fmt.go
index f995d2e2ec..51e139e319 100644
--- a/src/cmd/compile/internal/gc/fmt.go
+++ b/src/cmd/compile/internal/gc/fmt.go
@@ -339,14 +339,14 @@ func (n *Node) jconv(s fmt.State, flag FmtFlag) {
 	short := flag&FmtShort != 0
 
 	// Useful to see which nodes in an AST printout are actually identical
-	if Debug_dumpptrs != 0 {
+	if Debug.DumpPtrs != 0 {
 		fmt.Fprintf(s, " p(%p)", n)
 	}
 	if !short && n.Name != nil && n.Name.Vargen != 0 {
 		fmt.Fprintf(s, " g(%d)", n.Name.Vargen)
 	}
 
-	if Debug_dumpptrs != 0 && !short && n.Name != nil && n.Name.Defn != nil {
+	if Debug.DumpPtrs != 0 && !short && n.Name != nil && n.Name.Defn != nil {
 		// Useful to see where Defn is set and what node it points to
 		fmt.Fprintf(s, " defn(%p)", n.Name.Defn)
 	}
diff --git a/src/cmd/compile/internal/gc/go.go b/src/cmd/compile/internal/gc/go.go
index 6cab03d726..947dae476b 100644
--- a/src/cmd/compile/internal/gc/go.go
+++ b/src/cmd/compile/internal/gc/go.go
@@ -101,9 +101,6 @@ var pragcgobuf [][]string
 
 var decldepth int32
 
-var Debug_checknil int
-var Debug_typeassert int
-
 var localpkg *types.Pkg // package being compiled
 
 var inimport bool // set during import
@@ -189,8 +186,6 @@ var Ctxt *obj.Link
 
 var nodfp *Node
 
-var disable_checknil int
-
 var autogeneratedPos src.XPos
 
 // interface to back end
diff --git a/src/cmd/compile/internal/gc/inl.go b/src/cmd/compile/internal/gc/inl.go
index 50091e9c11..fc467dd95a 100644
--- a/src/cmd/compile/internal/gc/inl.go
+++ b/src/cmd/compile/internal/gc/inl.go
@@ -86,7 +86,7 @@ func typecheckinl(fn *Node) {
 		return // typecheckinl on local function
 	}
 
-	if Flag.LowerM > 2 || Debug_export != 0 {
+	if Flag.LowerM > 2 || Debug.Export != 0 {
 		fmt.Printf("typecheck import [%v] %L { %#v }\n", fn.Sym, fn, asNodes(fn.Func.Inl.Body))
 	}
 
@@ -144,7 +144,7 @@ func caninl(fn *Node) {
 	}
 
 	// If marked "go:nocheckptr" and -d checkptr compilation, don't inline.
-	if Debug_checkptr != 0 && fn.Func.Pragma&NoCheckPtr != 0 {
+	if Debug.Checkptr != 0 && fn.Func.Pragma&NoCheckPtr != 0 {
 		reason = "marked go:nocheckptr"
 		return
 	}
@@ -595,7 +595,7 @@ func inlnode(n *Node, maxCost int32, inlMap map[*Node]bool) *Node {
 	case OCALLMETH:
 		// Prevent inlining some reflect.Value methods when using checkptr,
 		// even when package reflect was compiled without it (#35073).
-		if s := n.Left.Sym; Debug_checkptr != 0 && isReflectPkg(s.Pkg) && (s.Name == "Value.UnsafeAddr" || s.Name == "Value.Pointer") {
+		if s := n.Left.Sym; Debug.Checkptr != 0 && isReflectPkg(s.Pkg) && (s.Name == "Value.UnsafeAddr" || s.Name == "Value.Pointer") {
 			return n
 		}
 	}
@@ -931,7 +931,7 @@ func mkinlcall(n, fn *Node, maxCost int32, inlMap map[*Node]bool) *Node {
 	defer func() {
 		inlMap[fn] = false
 	}()
-	if Debug_typecheckinl == 0 {
+	if Debug.TypecheckInl == 0 {
 		typecheckinl(fn)
 	}
 
diff --git a/src/cmd/compile/internal/gc/main.go b/src/cmd/compile/internal/gc/main.go
index 9cf988bca8..0d41f81a52 100644
--- a/src/cmd/compile/internal/gc/main.go
+++ b/src/cmd/compile/internal/gc/main.go
@@ -34,79 +34,8 @@ import (
 	"strings"
 )
 
-var (
-	Debug_append       int
-	Debug_checkptr     int
-	Debug_closure      int
-	Debug_compilelater int
-	debug_dclstack     int
-	Debug_dumpptrs     int
-	Debug_libfuzzer    int
-	Debug_panic        int
-	Debug_slice        int
-	Debug_wb           int
-	Debug_pctab        string
-	Debug_locationlist int
-	Debug_typecheckinl int
-	Debug_gendwarfinl  int
-	Debug_softfloat    int
-	Debug_defer        int
-)
-
-// Debug arguments.
-// These can be specified with the -d flag, as in "-d nil"
-// to set the debug_checknil variable.
-// Multiple options can be comma-separated.
-// Each option accepts an optional argument, as in "gcprog=2"
-var debugtab = []struct {
-	name string
-	help string
-	val  interface{} // must be *int or *string
-}{
-	{"append", "print information about append compilation", &Debug_append},
-	{"checkptr", "instrument unsafe pointer conversions", &Debug_checkptr},
-	{"closure", "print information about closure compilation", &Debug_closure},
-	{"compilelater", "compile functions as late as possible", &Debug_compilelater},
-	{"disablenil", "disable nil checks", &disable_checknil},
-	{"dclstack", "run internal dclstack check", &debug_dclstack},
-	{"dumpptrs", "show Node pointer values in Dump/dumplist output", &Debug_dumpptrs},
-	{"gcprog", "print dump of GC programs", &Debug_gcprog},
-	{"libfuzzer", "coverage instrumentation for libfuzzer", &Debug_libfuzzer},
-	{"nil", "print information about nil checks", &Debug_checknil},
-	{"panic", "do not hide any compiler panic", &Debug_panic},
-	{"slice", "print information about slice compilation", &Debug_slice},
-	{"typeassert", "print information about type assertion inlining", &Debug_typeassert},
-	{"wb", "print information about write barriers", &Debug_wb},
-	{"export", "print export data", &Debug_export},
-	{"pctab", "print named pc-value table", &Debug_pctab},
-	{"locationlists", "print information about DWARF location list creation", &Debug_locationlist},
-	{"typecheckinl", "eager typechecking of inline function bodies", &Debug_typecheckinl},
-	{"dwarfinl", "print information about DWARF inlined function creation", &Debug_gendwarfinl},
-	{"softfloat", "force compiler to emit soft-float code", &Debug_softfloat},
-	{"defer", "print information about defer compilation", &Debug_defer},
-	{"fieldtrack", "enable fieldtracking", &objabi.Fieldtrack_enabled},
-}
-
-const debugHelpHeader = `usage: -d arg[,arg]* and arg is <key>[=<value>]
-
-<key> is one of:
-
-`
-
-const debugHelpFooter = `
-<value> is key-specific.
-
-Key "checkptr" supports values:
-	"0": instrumentation disabled
-	"1": conversions involving unsafe.Pointer are instrumented
-	"2": conversions to unsafe.Pointer force heap allocation
-
-Key "pctab" supports values:
-	"pctospadj", "pctofile", "pctoline", "pctoinline", "pctopcdata"
-`
-
 func hidePanic() {
-	if Debug_panic == 0 && Errors() > 0 {
+	if Debug.Panic == 0 && Errors() > 0 {
 		// If we've already complained about things
 		// in the program, don't bother complaining
 		// about a panic too; let the user clean up
@@ -243,9 +172,9 @@ func Main(archInit func(*Arch)) {
 		instrumenting = true
 	}
 	if Flag.Dwarf {
-		dwarf.EnableLogging(Debug_gendwarfinl != 0)
+		dwarf.EnableLogging(Debug.DwarfInl != 0)
 	}
-	if Debug_softfloat != 0 {
+	if Debug.SoftFloat != 0 {
 		thearch.SoftFloat = true
 	}
 
@@ -396,7 +325,7 @@ func Main(archInit func(*Arch)) {
 
 	// Phase 5: Inlining
 	timings.Start("fe", "inlining")
-	if Debug_typecheckinl != 0 {
+	if Debug.TypecheckInl != 0 {
 		// Typecheck imported function bodies if Debug.l > 1,
 		// otherwise lazily when used or re-exported.
 		for _, n := range importlist {
@@ -501,7 +430,7 @@ func Main(archInit func(*Arch)) {
 	// DWARF inlining gen so as to avoid problems with generated
 	// method wrappers.
 	if Ctxt.DwFixups != nil {
-		Ctxt.DwFixups.Finalize(Ctxt.Pkgpath, Debug_gendwarfinl != 0)
+		Ctxt.DwFixups.Finalize(Ctxt.Pkgpath, Debug.DwarfInl != 0)
 		Ctxt.DwFixups = nil
 		Flag.GenDwarfInl = 0
 	}
@@ -944,7 +873,7 @@ func importfile(f constant.Value) *types.Pkg {
 		return nil
 
 	case 'B':
-		if Debug_export != 0 {
+		if Debug.Export != 0 {
 			fmt.Printf("importing %s (%s)\n", path_, file)
 		}
 		imp.ReadByte() // skip \n after $$B
diff --git a/src/cmd/compile/internal/gc/order.go b/src/cmd/compile/internal/gc/order.go
index ee0c8f2711..90c08b1b75 100644
--- a/src/cmd/compile/internal/gc/order.go
+++ b/src/cmd/compile/internal/gc/order.go
@@ -384,7 +384,7 @@ func orderMakeSliceCopy(s []*Node) {
 
 // edge inserts coverage instrumentation for libfuzzer.
 func (o *Order) edge() {
-	if Debug_libfuzzer == 0 {
+	if Debug.Libfuzzer == 0 {
 		return
 	}
 
@@ -998,7 +998,7 @@ func (o *Order) stmt(n *Node) {
 	// For now just clean all the temporaries at the end.
 	// In practice that's fine.
 	case OSWITCH:
-		if Debug_libfuzzer != 0 && !hasDefaultCase(n) {
+		if Debug.Libfuzzer != 0 && !hasDefaultCase(n) {
 			// Add empty "default:" case for instrumentation.
 			n.List.Append(nod(OCASE, nil, nil))
 		}
diff --git a/src/cmd/compile/internal/gc/pgen.go b/src/cmd/compile/internal/gc/pgen.go
index fe13a161bd..19a24a3235 100644
--- a/src/cmd/compile/internal/gc/pgen.go
+++ b/src/cmd/compile/internal/gc/pgen.go
@@ -291,7 +291,7 @@ func compilenow(fn *Node) bool {
 	if fn.IsMethod() && isInlinableButNotInlined(fn) {
 		return false
 	}
-	return Flag.LowerC == 1 && Debug_compilelater == 0
+	return Flag.LowerC == 1 && Debug.CompileLater == 0
 }
 
 // isInlinableButNotInlined returns true if 'fn' was marked as an
diff --git a/src/cmd/compile/internal/gc/print.go b/src/cmd/compile/internal/gc/print.go
index 6b5f670812..345f433fe4 100644
--- a/src/cmd/compile/internal/gc/print.go
+++ b/src/cmd/compile/internal/gc/print.go
@@ -208,7 +208,7 @@ func Fatalf(format string, args ...interface{}) {
 func FatalfAt(pos src.XPos, format string, args ...interface{}) {
 	flusherrors()
 
-	if Debug_panic != 0 || numErrors == 0 {
+	if Debug.Panic != 0 || numErrors == 0 {
 		fmt.Printf("%v: internal compiler error: ", linestr(pos))
 		fmt.Printf(format, args...)
 		fmt.Printf("\n")
diff --git a/src/cmd/compile/internal/gc/reflect.go b/src/cmd/compile/internal/gc/reflect.go
index 674a3bf3fb..11ccc15a25 100644
--- a/src/cmd/compile/internal/gc/reflect.go
+++ b/src/cmd/compile/internal/gc/reflect.go
@@ -1787,13 +1787,11 @@ type GCProg struct {
 	w      gcprog.Writer
 }
 
-var Debug_gcprog int // set by -d gcprog
-
 func (p *GCProg) init(lsym *obj.LSym) {
 	p.lsym = lsym
 	p.symoff = 4 // first 4 bytes hold program length
 	p.w.Init(p.writeByte)
-	if Debug_gcprog > 0 {
+	if Debug.GCProg > 0 {
 		fmt.Fprintf(os.Stderr, "compile: start GCProg for %v\n", lsym)
 		p.w.Debug(os.Stderr)
 	}
@@ -1807,7 +1805,7 @@ func (p *GCProg) end() {
 	p.w.End()
 	duint32(p.lsym, 0, uint32(p.symoff-4))
 	ggloblsym(p.lsym, int32(p.symoff), obj.DUPOK|obj.RODATA|obj.LOCAL)
-	if Debug_gcprog > 0 {
+	if Debug.GCProg > 0 {
 		fmt.Fprintf(os.Stderr, "compile: end GCProg for %v\n", p.lsym)
 	}
 }
diff --git a/src/cmd/compile/internal/gc/sinit.go b/src/cmd/compile/internal/gc/sinit.go
index 741e0ef9a3..1f89baa3c0 100644
--- a/src/cmd/compile/internal/gc/sinit.go
+++ b/src/cmd/compile/internal/gc/sinit.go
@@ -256,7 +256,7 @@ func (s *InitSchedule) staticassign(l *Node, r *Node) bool {
 
 	case OCLOSURE:
 		if hasemptycvars(r) {
-			if Debug_closure > 0 {
+			if Debug.Closure > 0 {
 				Warnl(r.Pos, "closure converted to global")
 			}
 			// Closures with no captured variables are globals,
diff --git a/src/cmd/compile/internal/gc/ssa.go b/src/cmd/compile/internal/gc/ssa.go
index 260df2f54f..f06f08e6ab 100644
--- a/src/cmd/compile/internal/gc/ssa.go
+++ b/src/cmd/compile/internal/gc/ssa.go
@@ -1102,7 +1102,7 @@ func (s *state) stmt(n *Node) {
 			}
 		}
 	case ODEFER:
-		if Debug_defer > 0 {
+		if Debug.Defer > 0 {
 			var defertype string
 			if s.hasOpenDefers {
 				defertype = "open-coded"
@@ -1232,12 +1232,12 @@ func (s *state) stmt(n *Node) {
 				// so there will be no write barriers,
 				// so there's no need to attempt to prevent them.
 				if s.canSSA(n.Left) {
-					if Debug_append > 0 { // replicating old diagnostic message
+					if Debug.Append > 0 { // replicating old diagnostic message
 						Warnl(n.Pos, "append: len-only update (in local slice)")
 					}
 					break
 				}
-				if Debug_append > 0 {
+				if Debug.Append > 0 {
 					Warnl(n.Pos, "append: len-only update")
 				}
 				s.append(rhs, true)
@@ -5026,7 +5026,7 @@ func (s *state) exprPtr(n *Node, bounded bool, lineno src.XPos) *ssa.Value {
 // Used only for automatically inserted nil checks,
 // not for user code like 'x != nil'.
 func (s *state) nilCheck(ptr *ssa.Value) {
-	if disable_checknil != 0 || s.curfn.Func.NilCheckDisabled() {
+	if Debug.DisableNil != 0 || s.curfn.Func.NilCheckDisabled() {
 		return
 	}
 	s.newValue2(ssa.OpNilCheck, types.TypeVoid, ptr, s.mem())
@@ -5837,7 +5837,7 @@ func (s *state) dottype(n *Node, commaok bool) (res, resok *ssa.Value) {
 		if n.Type.IsEmptyInterface() {
 			// Converting to an empty interface.
 			// Input could be an empty or nonempty interface.
-			if Debug_typeassert > 0 {
+			if Debug.TypeAssert > 0 {
 				Warnl(n.Pos, "type assertion inlined")
 			}
 
@@ -5904,7 +5904,7 @@ func (s *state) dottype(n *Node, commaok bool) (res, resok *ssa.Value) {
 			return
 		}
 		// converting to a nonempty interface needs a runtime call.
-		if Debug_typeassert > 0 {
+		if Debug.TypeAssert > 0 {
 			Warnl(n.Pos, "type assertion not inlined")
 		}
 		if n.Left.Type.IsEmptyInterface() {
@@ -5921,14 +5921,14 @@ func (s *state) dottype(n *Node, commaok bool) (res, resok *ssa.Value) {
 		return s.rtcall(assertI2I, true, []*types.Type{n.Type}, target, iface)[0], nil
 	}
 
-	if Debug_typeassert > 0 {
+	if Debug.TypeAssert > 0 {
 		Warnl(n.Pos, "type assertion inlined")
 	}
 
 	// Converting to a concrete type.
 	direct := isdirectiface(n.Type)
 	itab := s.newValue1(ssa.OpITab, byteptr, iface) // type word of interface
-	if Debug_typeassert > 0 {
+	if Debug.TypeAssert > 0 {
 		Warnl(n.Pos, "type assertion inlined")
 	}
 	var targetITab *ssa.Value
@@ -6474,7 +6474,7 @@ func genssa(f *ssa.Func, pp *Progs) {
 	}
 
 	if Ctxt.Flag_locationlists {
-		e.curfn.Func.DebugInfo = ssa.BuildFuncDebug(Ctxt, f, Debug_locationlist > 1, stackOffset)
+		e.curfn.Func.DebugInfo = ssa.BuildFuncDebug(Ctxt, f, Debug.LocationLists > 1, stackOffset)
 		bstart := s.bstart
 		// Note that at this moment, Prog.Pc is a sequence number; it's
 		// not a real PC until after assembly, so this mapping has to
@@ -7113,7 +7113,7 @@ func (e *ssafn) Warnl(pos src.XPos, fmt_ string, args ...interface{}) {
 }
 
 func (e *ssafn) Debug_checknil() bool {
-	return Debug_checknil != 0
+	return Debug.Nil != 0
 }
 
 func (e *ssafn) UseWriteBarrier() bool {
diff --git a/src/cmd/compile/internal/gc/subr.go b/src/cmd/compile/internal/gc/subr.go
index 32312e9545..989d10a561 100644
--- a/src/cmd/compile/internal/gc/subr.go
+++ b/src/cmd/compile/internal/gc/subr.go
@@ -1412,7 +1412,7 @@ func genwrapper(rcvr *types.Type, method *types.Field, newnam *types.Sym) {
 	}
 
 	funcbody()
-	if debug_dclstack != 0 {
+	if Debug.DclStack != 0 {
 		testdclstack()
 	}
 
diff --git a/src/cmd/compile/internal/gc/syntax.go b/src/cmd/compile/internal/gc/syntax.go
index 75a7ae2c7a..f771a7184e 100644
--- a/src/cmd/compile/internal/gc/syntax.go
+++ b/src/cmd/compile/internal/gc/syntax.go
@@ -764,7 +764,7 @@ func (f *Func) SetInstrumentBody(b bool)           { f.flags.set(funcInstrumentB
 func (f *Func) SetOpenCodedDeferDisallowed(b bool) { f.flags.set(funcOpenCodedDeferDisallowed, b) }
 
 func (f *Func) setWBPos(pos src.XPos) {
-	if Debug_wb != 0 {
+	if Debug.WB != 0 {
 		Warnl(pos, "write barrier")
 	}
 	if !f.WBPos.IsKnown() {
diff --git a/src/cmd/compile/internal/gc/walk.go b/src/cmd/compile/internal/gc/walk.go
index c2d8411a59..de2733909e 100644
--- a/src/cmd/compile/internal/gc/walk.go
+++ b/src/cmd/compile/internal/gc/walk.go
@@ -1685,7 +1685,7 @@ func reduceSlice(n *Node) *Node {
 	n.SetSliceBounds(low, high, max)
 	if (n.Op == OSLICE || n.Op == OSLICESTR) && low == nil && high == nil {
 		// Reduce x[:] to x.
-		if Debug_slice > 0 {
+		if Debug.Slice > 0 {
 			Warn("slice: omit slice operation")
 		}
 		return n.Left
@@ -3262,7 +3262,7 @@ func walkcompare(n *Node, init *Nodes) *Node {
 
 	switch t.Etype {
 	default:
-		if Debug_libfuzzer != 0 && t.IsInteger() {
+		if Debug.Libfuzzer != 0 && t.IsInteger() {
 			n.Left = cheapexpr(n.Left, init)
 			n.Right = cheapexpr(n.Right, init)
 
@@ -4087,5 +4087,5 @@ func walkCheckPtrArithmetic(n *Node, init *Nodes) *Node {
 // function fn at a given level. See debugHelpFooter for defined
 // levels.
 func checkPtr(fn *Node, level int) bool {
-	return Debug_checkptr >= level && fn.Func.Pragma&NoCheckPtr == 0
+	return Debug.Checkptr >= level && fn.Func.Pragma&NoCheckPtr == 0
 }
diff --git a/src/cmd/compile/internal/mips/ssa.go b/src/cmd/compile/internal/mips/ssa.go
index 9d11c6bf53..1d2e2c79e6 100644
--- a/src/cmd/compile/internal/mips/ssa.go
+++ b/src/cmd/compile/internal/mips/ssa.go
@@ -766,7 +766,7 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 		if logopt.Enabled() {
 			logopt.LogOpt(v.Pos, "nilcheck", "genssa", v.Block.Func.Name)
 		}
-		if gc.Debug_checknil != 0 && v.Pos.Line() > 1 { // v.Pos.Line()==1 in generated wrappers
+		if gc.Debug.Nil != 0 && v.Pos.Line() > 1 { // v.Pos.Line()==1 in generated wrappers
 			gc.Warnl(v.Pos, "generated nil check")
 		}
 	case ssa.OpMIPSFPFlagTrue,
diff --git a/src/cmd/compile/internal/mips64/ssa.go b/src/cmd/compile/internal/mips64/ssa.go
index 2727c4d8a8..067b8158c9 100644
--- a/src/cmd/compile/internal/mips64/ssa.go
+++ b/src/cmd/compile/internal/mips64/ssa.go
@@ -724,7 +724,7 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 		if logopt.Enabled() {
 			logopt.LogOpt(v.Pos, "nilcheck", "genssa", v.Block.Func.Name)
 		}
-		if gc.Debug_checknil != 0 && v.Pos.Line() > 1 { // v.Pos.Line()==1 in generated wrappers
+		if gc.Debug.Nil != 0 && v.Pos.Line() > 1 { // v.Pos.Line()==1 in generated wrappers
 			gc.Warnl(v.Pos, "generated nil check")
 		}
 	case ssa.OpMIPS64FPFlagTrue,
diff --git a/src/cmd/compile/internal/ppc64/ssa.go b/src/cmd/compile/internal/ppc64/ssa.go
index 3e20c44a4c..f0e7c41923 100644
--- a/src/cmd/compile/internal/ppc64/ssa.go
+++ b/src/cmd/compile/internal/ppc64/ssa.go
@@ -1852,7 +1852,7 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 		if logopt.Enabled() {
 			logopt.LogOpt(v.Pos, "nilcheck", "genssa", v.Block.Func.Name)
 		}
-		if gc.Debug_checknil != 0 && v.Pos.Line() > 1 { // v.Pos.Line()==1 in generated wrappers
+		if gc.Debug.Nil != 0 && v.Pos.Line() > 1 { // v.Pos.Line()==1 in generated wrappers
 			gc.Warnl(v.Pos, "generated nil check")
 		}
 
diff --git a/src/cmd/compile/internal/riscv64/ssa.go b/src/cmd/compile/internal/riscv64/ssa.go
index 0beb5b4bd1..d49927ee04 100644
--- a/src/cmd/compile/internal/riscv64/ssa.go
+++ b/src/cmd/compile/internal/riscv64/ssa.go
@@ -586,7 +586,7 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 		gc.AddAux(&p.From, v)
 		p.To.Type = obj.TYPE_REG
 		p.To.Reg = riscv.REG_ZERO
-		if gc.Debug_checknil != 0 && v.Pos.Line() > 1 { // v.Pos == 1 in generated wrappers
+		if gc.Debug.Nil != 0 && v.Pos.Line() > 1 { // v.Pos == 1 in generated wrappers
 			gc.Warnl(v.Pos, "generated nil check")
 		}
 
diff --git a/src/cmd/compile/internal/s390x/ssa.go b/src/cmd/compile/internal/s390x/ssa.go
index 8037357131..cb13f8d3c0 100644
--- a/src/cmd/compile/internal/s390x/ssa.go
+++ b/src/cmd/compile/internal/s390x/ssa.go
@@ -642,7 +642,7 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 		if logopt.Enabled() {
 			logopt.LogOpt(v.Pos, "nilcheck", "genssa", v.Block.Func.Name)
 		}
-		if gc.Debug_checknil != 0 && v.Pos.Line() > 1 { // v.Pos.Line()==1 in generated wrappers
+		if gc.Debug.Nil != 0 && v.Pos.Line() > 1 { // v.Pos.Line()==1 in generated wrappers
 			gc.Warnl(v.Pos, "generated nil check")
 		}
 	case ssa.OpS390XMVC:
diff --git a/src/cmd/compile/internal/wasm/ssa.go b/src/cmd/compile/internal/wasm/ssa.go
index a36fbca4e0..3f05515b9a 100644
--- a/src/cmd/compile/internal/wasm/ssa.go
+++ b/src/cmd/compile/internal/wasm/ssa.go
@@ -165,7 +165,7 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 		if logopt.Enabled() {
 			logopt.LogOpt(v.Pos, "nilcheck", "genssa", v.Block.Func.Name)
 		}
-		if gc.Debug_checknil != 0 && v.Pos.Line() > 1 { // v.Pos.Line()==1 in generated wrappers
+		if gc.Debug.Nil != 0 && v.Pos.Line() > 1 { // v.Pos.Line()==1 in generated wrappers
 			gc.Warnl(v.Pos, "generated nil check")
 		}
 
diff --git a/src/cmd/compile/internal/x86/ssa.go b/src/cmd/compile/internal/x86/ssa.go
index fbf76d0c5e..65d7e75a53 100644
--- a/src/cmd/compile/internal/x86/ssa.go
+++ b/src/cmd/compile/internal/x86/ssa.go
@@ -850,7 +850,7 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 		if logopt.Enabled() {
 			logopt.LogOpt(v.Pos, "nilcheck", "genssa", v.Block.Func.Name)
 		}
-		if gc.Debug_checknil != 0 && v.Pos.Line() > 1 { // v.Pos.Line()==1 in generated wrappers
+		if gc.Debug.Nil != 0 && v.Pos.Line() > 1 { // v.Pos.Line()==1 in generated wrappers
 			gc.Warnl(v.Pos, "generated nil check")
 		}
 	case ssa.OpClobber: