Revert "cmd/compile: enable Asan check for global variables"

This reverts CL 401775.

Reason for revert: broke build.

Change-Id: I4f6f2edff1e4afcf31cd90e26dacf303979eb10c
Reviewed-on: https://go-review.googlesource.com/c/go/+/403981
Reviewed-by: Daniel Martí <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>
Auto-Submit: Bryan Mills <[email protected]>
Run-TryBot: Bryan Mills <[email protected]>
Reviewed-by: Keith Randall <[email protected]>
Reviewed-by: Keith Randall <[email protected]>

Author: Bryan Mills

misc/cgo/testsanitizers/asan_test.go

@@ -22,14 +22,6 @@ func TestASAN(t *testing.T) {
 	if !aSanSupported(goos, goarch) {
 		t.Skipf("skipping on %s/%s; -asan option is not supported.", goos, goarch)
 	}
-	// The current implementation is only compatible with the ASan library from version
-	// v7 to v9 (See the description in src/runtime/asan/asan.go). Therefore, using the
-	// -asan option must use a compatible version of ASan library, which requires that
-	// the gcc version is not less than 7 and the clang version is not less than 9,
-	// otherwise a segmentation fault will occur.
-	if !compilerRequiredAsanVersion() {
-		t.Skipf("skipping: too old version of compiler")
-	}
 
 	t.Parallel()
 	requireOvercommit(t)

misc/cgo/testsanitizers/cc_test.go

@@ -184,16 +184,17 @@ func compilerVersion() (version, error) {
 			var match [][]byte
 			if bytes.HasPrefix(out, []byte("gcc")) {
 				compiler.name = "gcc"
-				cmd, err := cc("-v")
+
+				cmd, err := cc("-dumpversion")
 				if err != nil {
 					return err
 				}
-				out, err := cmd.CombinedOutput()
+				out, err := cmd.Output()
 				if err != nil {
-					// gcc, but does not support gcc's "-v" flag?!
+					// gcc, but does not support gcc's "-dumpversion" flag?!
 					return err
 				}
-				gccRE := regexp.MustCompile(`gcc version (\d+)\.(\d+)`)
+				gccRE := regexp.MustCompile(`(\d+)\.(\d+)`)
 				match = gccRE.FindSubmatch(out)
 			} else {
 				clangRE := regexp.MustCompile(`clang version (\d+)\.(\d+)`)
@@ -234,22 +235,6 @@ func compilerSupportsLocation() bool {
 	}
 }
 
-// compilerRequiredAsanVersion reports whether the compiler is the version required by Asan.
-func compilerRequiredAsanVersion() bool {
-	compiler, err := compilerVersion()
-	if err != nil {
-		return false
-	}
-	switch compiler.name {
-	case "gcc":
-		return compiler.major >= 7
-	case "clang":
-		return compiler.major >= 9
-	default:
-		return false
-	}
-}
-
 type compilerCheck struct {
 	once sync.Once
 	err  error

src/cmd/compile/internal/base/base.go

@@ -70,7 +70,6 @@ var NoInstrumentPkgs = []string{
 	"runtime/msan",
 	"runtime/asan",
 	"internal/cpu",
-	"buildcfg",
 }
 
 // Don't insert racefuncenter/racefuncexit into the following packages.

src/cmd/compile/internal/gc/obj.go

@@ -9,7 +9,6 @@ import (
 	"cmd/compile/internal/ir"
 	"cmd/compile/internal/noder"
 	"cmd/compile/internal/objw"
-	"cmd/compile/internal/pkginit"
 	"cmd/compile/internal/reflectdata"
 	"cmd/compile/internal/staticdata"
 	"cmd/compile/internal/typecheck"
@@ -111,6 +110,7 @@ func dumpCompilerObj(bout *bio.Writer) {
 func dumpdata() {
 	numExterns := len(typecheck.Target.Externs)
 	numDecls := len(typecheck.Target.Decls)
+
 	dumpglobls(typecheck.Target.Externs)
 	reflectdata.CollectPTabs()
 	numExports := len(typecheck.Target.Exports)
@@ -287,20 +287,7 @@ func ggloblnod(nam *ir.Name) {
 	if nam.Type() != nil && !nam.Type().HasPointers() {
 		flags |= obj.NOPTR
 	}
-	size := nam.Type().Size()
-	linkname := nam.Sym().Linkname
-	name := nam.Sym().Name
-
-	// We've skipped linkname'd globals's instrument, so we can skip them here as well.
-	if base.Flag.ASan && linkname == "" && pkginit.InstrumentGlobalsMap[name] != nil {
-		// Write the new size of instrumented global variables that have
-		// trailing redzones into object file.
-		rzSize := pkginit.GetRedzoneSizeForGlobal(size)
-		sizeWithRZ := rzSize + size
-		base.Ctxt.Globl(s, sizeWithRZ, flags)
-	} else {
-		base.Ctxt.Globl(s, size, flags)
-	}
+	base.Ctxt.Globl(s, nam.Type().Size(), flags)
 	if nam.LibfuzzerExtraCounter() {
 		s.Type = objabi.SLIBFUZZER_EXTRA_COUNTER
 	}

src/cmd/compile/internal/noder/noder.go

@@ -442,7 +442,7 @@ func parseGoEmbed(args string) ([]string, error) {
 // the name, normally "pkg.init", is altered to "pkg.init.0".
 var renameinitgen int
 
-func Renameinit() *types.Sym {
+func renameinit() *types.Sym {
 	s := typecheck.LookupNum("init.", renameinitgen)
 	renameinitgen++
 	return s

src/cmd/compile/internal/noder/object.go

@@ -104,7 +104,7 @@ func (g *irgen) obj(obj types2.Object) *ir.Name {
 		var typ *types.Type
 		if recv := sig.Recv(); recv == nil {
 			if obj.Name() == "init" {
-				sym = Renameinit()
+				sym = renameinit()
 			} else {
 				sym = g.sym(obj)
 			}

src/cmd/compile/internal/noder/reader.go

@@ -645,7 +645,7 @@ func (pr *pkgReader) objIdx(idx int, implicits, explicits []*types.Type) ir.Node
 
 	case pkgbits.ObjFunc:
 		if sym.Name == "init" {
-			sym = Renameinit()
+			sym = renameinit()
 		}
 		name := do(ir.ONAME, true)
 		setType(name, r.signature(sym.Pkg, nil))

src/cmd/compile/internal/pkginit/init.go

@@ -7,7 +7,6 @@ package pkginit
 import (
 	"cmd/compile/internal/base"
 	"cmd/compile/internal/ir"
-	"cmd/compile/internal/noder"
 	"cmd/compile/internal/objw"
 	"cmd/compile/internal/staticinit"
 	"cmd/compile/internal/typecheck"
@@ -84,58 +83,6 @@ func Task() *ir.Name {
 		}
 		deps = append(deps, n.(*ir.Name).Linksym())
 	}
-	if base.Flag.ASan {
-		// Make an initialization function to call runtime.asanregisterglobals to register an
-		// array of instrumented global variables when -asan is enabled. An instrumented global
-		// variable is described by a structure.
-		// See the _asan_global structure declared in src/runtime/asan/asan.go.
-		//
-		// func init {
-		// 		var globals []_asan_global {...}
-		// 		asanregisterglobals(&globals[0], len(globals))
-		// }
-		for _, n := range typecheck.Target.Externs {
-			if canInstrumentGlobal(n) {
-				name := n.Sym().Name
-				InstrumentGlobalsMap[name] = n
-				InstrumentGlobalsSlice = append(InstrumentGlobalsSlice, n)
-			}
-		}
-		ni := len(InstrumentGlobalsMap)
-		if ni != 0 {
-			// Make an init._ function.
-			base.Pos = base.AutogeneratedPos
-			typecheck.DeclContext = ir.PEXTERN
-			name := noder.Renameinit()
-			fnInit := typecheck.DeclFunc(name, ir.NewFuncType(base.Pos, nil, nil, nil))
-
-			// Get an array of intrumented global variables.
-			globals := instrumentGlobals(fnInit)
-
-			// Call runtime.asanregisterglobals function to poison redzones.
-			// runtime.asanregisterglobals(unsafe.Pointer(&globals[0]), ni)
-			asanf := typecheck.NewName(ir.Pkgs.Runtime.Lookup("asanregisterglobals"))
-			ir.MarkFunc(asanf)
-			asanf.SetType(types.NewSignature(types.NoPkg, nil, nil, []*types.Field{
-				types.NewField(base.Pos, nil, types.Types[types.TUNSAFEPTR]),
-				types.NewField(base.Pos, nil, types.Types[types.TUINTPTR]),
-			}, nil))
-			asancall := ir.NewCallExpr(base.Pos, ir.OCALL, asanf, nil)
-			asancall.Args.Append(typecheck.ConvNop(typecheck.NodAddr(
-				ir.NewIndexExpr(base.Pos, globals, ir.NewInt(0))), types.Types[types.TUNSAFEPTR]))
-			asancall.Args.Append(typecheck.ConvNop(ir.NewInt(int64(ni)), types.Types[types.TUINTPTR]))
-
-			fnInit.Body.Append(asancall)
-			typecheck.FinishFuncBody()
-			typecheck.Func(fnInit)
-			ir.CurFunc = fnInit
-			typecheck.Stmts(fnInit.Body)
-			ir.CurFunc = nil
-
-			typecheck.Target.Decls = append(typecheck.Target.Decls, fnInit)
-			typecheck.Target.Inits = append(typecheck.Target.Inits, fnInit)
-		}
-	}
 
 	// Record user init functions.
 	for _, fn := range typecheck.Target.Inits {