cmd/vet/all: use x/tools/go/analysis/cmd/vet not cmd/vet

cmd/vet/all applies vet to all packages in the standard tree.
It is run for every configuration using this command:
  GO_BUILDER_NAME=misc-vetall go tool dist test
by the misc-vetall builder (see chart at build.golang.org).

Ideally we would switch to 'go vet', but it effectively does a partial
build. This means that its analysis has accurate type information, so
it reports slightly fewer spurious diagnostics. However, it is more
than twice as slow.

Instead, cmd/vet/all builds and runs
golang.org/x/tools/go/analysis/cmd/vet, which uses x/tools/go/packages
to load the entire std lib from source. It takes about 4min to run all
OS/ARCH pairs. An important consequence is that golang.org/x/tools
must be on your $GOPATH to run cmd/vet/all. The test has been
temporarily modified to warn and skip if this is not the case.

This is a preparatory step for switching to the new
cmd/vet based on vet-lite.

Whitelist changes:
- The two "deadcode" diagnostics removed from the whitelist were due
  to if-conditions that could now be proven false.
- The asmdecl warnings are now printed with the log.Printf prefix,
  so they are discarded by the parser and needn't be whitelisted.

Change-Id: I6486508b0de2cd947c897523af086a408cbaf4a8
Reviewed-on: https://go-review.googlesource.com/c/149097Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/cmd/vet/all/main.go

@@ -7,6 +7,9 @@
 // The vet/all command runs go vet on the standard library and commands.
 // It compares the output against a set of whitelists
 // maintained in the whitelist directory.
+//
+// This program attempts to build packages from golang.org/x/tools,
+// which must be in your GOPATH.
 package main
 
 import (
@@ -18,6 +21,7 @@ import (
 	"go/types"
 	"internal/testenv"
 	"io"
+	"io/ioutil"
 	"log"
 	"os"
 	"os/exec"
@@ -217,13 +221,40 @@ func (p platform) vet() {
 	w := make(whitelist)
 	w.load(p.os, p.arch)
 
-	// 'go tool vet .' is considerably faster than 'go vet ./...'
+	tmpdir, err := ioutil.TempDir("", "cmd-vet-all")
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer os.RemoveAll(tmpdir)
+
+	// Build the go/packages-based vet command from the x/tools
+	// repo. It is considerably faster than "go vet", which rebuilds
+	// the standard library.
+	vetTool := filepath.Join(tmpdir, "vet")
+	cmd := exec.Command(cmdGoPath, "build", "-o", vetTool, "golang.org/x/tools/go/analysis/cmd/vet")
+	cmd.Dir = filepath.Join(runtime.GOROOT(), "src")
+	cmd.Stderr = os.Stderr
+	cmd.Stdout = os.Stderr
+	if err := cmd.Run(); err != nil {
+		if _, err := build.Default.Import("golang.org/x/tools/go/analysis/cmd/vet", "", 0); err != nil {
+			fmt.Printf("skipping because golang.org/x/tools is not in GOPATH")
+			return
+		}
+		log.Fatal(err)
+	}
+
 	// TODO: The unsafeptr checks are disabled for now,
 	// because there are so many false positives,
 	// and no clear way to improve vet to eliminate large chunks of them.
 	// And having them in the whitelists will just cause annoyance
 	// and churn when working on the runtime.
-	cmd := exec.Command(cmdGoPath, "tool", "vet", "-unsafeptr=false", "-source", ".")
+	cmd = exec.Command(vetTool,
+		"-unsafeptr=0",
+		"-nilness=0", // expensive, uses SSA
+		"std",
+		"cmd/...",
+		"cmd/compile/internal/gc/testdata",
+	)
 	cmd.Dir = filepath.Join(runtime.GOROOT(), "src")
 	cmd.Env = append(os.Environ(), "GOOS="+p.os, "GOARCH="+p.arch, "CGO_ENABLED=0")
 	stderr, err := cmd.StderrPipe()
@@ -243,6 +274,9 @@ NextLine:
 		if strings.HasPrefix(line, "vet: ") {
 			// Typecheck failure: Malformed syntax or multiple packages or the like.
 			// This will yield nicer error messages elsewhere, so ignore them here.
+
+			// This includes warnings from asmdecl of the form:
+			//   "vet: foo.s:16: [amd64] cannot check cross-package assembly function"
 			continue
 		}
 
@@ -254,22 +288,48 @@ NextLine:
 			io.Copy(os.Stderr, stderr)
 			break
 		}
+		if strings.HasPrefix(line, "# ") {
+			// 'go vet' prefixes the output of each vet invocation by a comment:
+			//    # [package]
+			continue
+		}
 
-		fields := strings.SplitN(line, ":", 3)
+		// Parse line.
+		// Assume the part before the first ": "
+		// is the "file:line:col: " information.
+		// TODO(adonovan): parse vet -json output.
 		var file, lineno, msg string
-		switch len(fields) {
-		case 2:
-			// vet message with no line number
-			file, msg = fields[0], fields[1]
-		case 3:
-			file, lineno, msg = fields[0], fields[1], fields[2]
-		default:
+		if i := strings.Index(line, ": "); i >= 0 {
+			msg = line[i+len(": "):]
+
+			words := strings.Split(line[:i], ":")
+			switch len(words) {
+			case 3:
+				_ = words[2] // ignore column
+				fallthrough
+			case 2:
+				lineno = words[1]
+				fallthrough
+			case 1:
+				file = words[0]
+
+				// Make the file name relative to GOROOT/src.
+				if rel, err := filepath.Rel(cmd.Dir, file); err == nil {
+					file = rel
+				}
+			default:
+				// error: too many columns
+			}
+		}
+		if file == "" {
 			if !parseFailed {
 				parseFailed = true
 				fmt.Fprintf(os.Stderr, "failed to parse %s vet output:\n", p)
 			}
 			fmt.Fprintln(os.Stderr, line)
+			continue
 		}
+
 		msg = strings.TrimSpace(msg)
 
 		for _, ignore := range ignorePathPrefixes {

src/cmd/vet/all/whitelist/386.txt

 // 386-specific vet whitelist. See readme.txt for details.
 
-internal/bytealg/compare_386.s: [386] cannot check cross-package assembly function: cmpstring is in package runtime
-
 // startup code uses non-standard calling convention and intentionally
 // omits args.
 runtime/asm_386.s: [386] rt0_go: use of 4(SP) points beyond argument frame

src/cmd/vet/all/whitelist/all.txt

@@ -9,10 +9,6 @@ go/types/scope.go: method WriteTo(w io.Writer, n int, recurse bool) should have
 
 // False positives.
 
-// Nothing much to do about cross-package assembly. Unfortunate.
-internal/bytealg/equal_ARCHSUFF.s: [GOARCH] cannot check cross-package assembly function: memequal is in package runtime
-internal/bytealg/equal_ARCHSUFF.s: [GOARCH] cannot check cross-package assembly function: memequal_varlen is in package runtime
-
 // The write barrier is called directly by the compiler, so no Go def
 runtime/asm_ARCHSUFF.s: [GOARCH] gcWriteBarrier: function gcWriteBarrier missing Go declaration
 
@@ -22,8 +18,6 @@ encoding/json/decode_test.go: struct field m has json tag but is not exported
 encoding/json/decode_test.go: struct field m2 has json tag but is not exported
 encoding/json/decode_test.go: struct field s has json tag but is not exported
 encoding/json/tagkey_test.go: struct field tag `:"BadFormat"` not compatible with reflect.StructTag.Get: bad syntax for struct tag key
-runtime/testdata/testprog/deadlock.go: unreachable code
-runtime/testdata/testprog/deadlock.go: unreachable code
 
 // Compiler tests that make sure even vet-failing code adheres to the spec.
 cmd/compile/internal/gc/testdata/arithConst_test.go: a (64 bits) too small for shift of 4294967296
@@ -68,3 +62,7 @@ cmd/link/link_test.go: struct field tag "\n\tLondon. Michaelmas term lately over
 cmd/link/link_test.go: struct field tag "\n\tIt was grand to see how the wind awoke, and bent the trees, and drove the rain before it like a cloud of smoke; and to hear the solemn thunder, and to see the lightning; and while thinking with awe of the tremendous powers by which our little lives are encompassed, to consider how beneficent they are, and how upon the smallest flower and leaf there was already a freshness poured from all this seeming rage, which seemed to make creation new again." not compatible with reflect.StructTag.Get: bad syntax for struct tag key
 cmd/link/link_test.go: struct field tag "\n\tJarndyce and Jarndyce drones on. This scarecrow of a suit has, over the course of time, become so complicated, that no man alive knows what it means. The parties to it understand it least; but it has been observed that no two Chancery lawyers can talk about it for five minutes, without coming to a total disagreement as to all the premises. Innumerable children have been born into the cause; innumerable young people have married into it; innumerable old people have died out of it. Scores of persons have deliriously found themselves made parties in Jarndyce and Jarndyce, without knowing how or why; whole families have inherited legendary hatreds with the suit. The little plaintiff or defendant, who was promised a new rocking-horse when Jarndyce and Jarndyce should be settled, has grown up, possessed himself of a real horse, and trotted away into the other world. Fair wards of court have faded into mothers and grandmothers; a long procession of Chancellors has come in and gone out; the legion of bills in the suit have been transformed into mere bills of mortality; there are not three Jarndyces left upon the earth perhaps, since old Tom Jarndyce in despair blew his brains out at a coffee-house in Chancery Lane; but Jarndyce and Jarndyce still drags its dreary length before the Court, perennially hopeless." not compatible with reflect.StructTag.Get: bad syntax for struct tag key
 cmd/link/link_test.go: struct field tag "\n\tThe one great principle of the English law is, to make business for itself. There is no other principle distinctly, certainly, and consistently maintained through all its narrow turnings. Viewed by this light it becomes a coherent scheme, and not the monstrous maze the laity are apt to think it. Let them but once clearly perceive that its grand principle is to make business for itself at their expense, and surely they will cease to grumble." not compatible with reflect.StructTag.Get: bad syntax for struct tag key
+
+// Tests of Decode(nil) trigger legitimate diagnostics.
+encoding/gob/encoder_test.go: call of Decode passes non-pointer
+encoding/gob/encoder_test.go: call of Decode passes non-pointer

src/cmd/vet/all/whitelist/amd64.txt

@@ -2,9 +2,6 @@
 
 // False positives.
 
-// Nothing much to do about cross-package assembly. Unfortunate.
-internal/bytealg/compare_amd64.s: [amd64] cannot check cross-package assembly function: cmpstring is in package runtime
-
 // reflect trampolines intentionally omit arg size. Same for morestack.
 runtime/asm_amd64.s: [amd64] morestack: use of 8(SP) points beyond argument frame
 runtime/asm_amd64.s: [amd64] morestack: use of 16(SP) points beyond argument frame

src/cmd/vet/all/whitelist/arm.txt

 // arm-specific vet whitelist. See readme.txt for details.
 
-internal/bytealg/compare_arm.s: [arm] cannot check cross-package assembly function: cmpstring is in package runtime
-
 // Intentionally missing declarations.
 runtime/asm_arm.s: [arm] emptyfunc: function emptyfunc missing Go declaration
 runtime/asm_arm.s: [arm] armPublicationBarrier: function armPublicationBarrier missing Go declaration

src/cmd/vet/all/whitelist/arm64.txt

 // arm64-specific vet whitelist. See readme.txt for details.
 
-internal/bytealg/compare_arm64.s: [arm64] cannot check cross-package assembly function: cmpstring is in package runtime
-
 // Intentionally missing declarations.
 runtime/asm_arm64.s: [arm64] addmoduledata: function addmoduledata missing Go declaration
 runtime/duff_arm64.s: [arm64] duffzero: function duffzero missing Go declaration

src/cmd/vet/all/whitelist/mipsx.txt

 // mips/mipsle-specific vet whitelist. See readme.txt for details.
 
-internal/bytealg/compare_mipsx.s: [GOARCH] cannot check cross-package assembly function: cmpstring is in package runtime
-
 runtime/tls_mipsx.s: [GOARCH] save_g: function save_g missing Go declaration
 runtime/tls_mipsx.s: [GOARCH] load_g: function load_g missing Go declaration
 runtime/sys_linux_mipsx.s: [GOARCH] clone: 12(R29) should be mp+8(FP)

src/cmd/vet/all/whitelist/nacl_386.txt

 // nacl/386-specific vet whitelist. See readme.txt for details.
 
-runtime/sys_nacl_386.s: [386] cannot check cross-package assembly function: naclWrite is in package syscall
-runtime/sys_nacl_386.s: [386] cannot check cross-package assembly function: now is in package syscall
 runtime/sys_nacl_386.s: [386] nacl_clock_gettime: function nacl_clock_gettime missing Go declaration
 runtime/sys_nacl_386.s: [386] setldt: function setldt missing Go declaration
 runtime/sys_nacl_386.s: [386] sigtramp: use of 20(SP) points beyond argument frame

src/cmd/vet/all/whitelist/nacl_amd64p32.txt

 // nacl/amd64p32-specific vet whitelist. See readme.txt for details.
 
-internal/bytealg/compare_amd64p32.s: [amd64p32] cannot check cross-package assembly function: cmpstring is in package runtime
-
 // reflect trampolines intentionally omit arg size. Same for morestack.
 runtime/asm_amd64p32.s: [amd64p32] morestack: use of 8(SP) points beyond argument frame
 runtime/asm_amd64p32.s: [amd64p32] morestack: use of 16(SP) points beyond argument frame
@@ -13,8 +11,6 @@ runtime/sys_nacl_amd64p32.s: [amd64p32] sigtramp: unknown variable ctxt
 runtime/sys_nacl_amd64p32.s: [amd64p32] sigtramp: unknown variable ctxt
 runtime/sys_nacl_amd64p32.s: [amd64p32] sigtramp: unknown variable ctxt
 runtime/sys_nacl_amd64p32.s: [amd64p32] nacl_sysinfo: function nacl_sysinfo missing Go declaration
-runtime/sys_nacl_amd64p32.s: [amd64p32] cannot check cross-package assembly function: naclWrite is in package syscall
-runtime/sys_nacl_amd64p32.s: [amd64p32] cannot check cross-package assembly function: now is in package syscall
 runtime/sys_nacl_amd64p32.s: [amd64p32] nacl_clock_gettime: function nacl_clock_gettime missing Go declaration
 runtime/sys_nacl_amd64p32.s: [amd64p32] settls: function settls missing Go declaration
 

src/cmd/vet/all/whitelist/nacl_arm.txt

 // nacl/arm-specific vet whitelist. See readme.txt for details.
 
 runtime/asm_arm.s: [arm] sigreturn: function sigreturn missing Go declaration
-runtime/sys_nacl_arm.s: [arm] cannot check cross-package assembly function: naclWrite is in package syscall
-runtime/sys_nacl_arm.s: [arm] cannot check cross-package assembly function: now is in package syscall
 runtime/sys_nacl_arm.s: [arm] nacl_clock_gettime: function nacl_clock_gettime missing Go declaration
 runtime/sys_nacl_arm.s: [arm] nacl_sysinfo: function nacl_sysinfo missing Go declaration
 runtime/sys_nacl_arm.s: [arm] read_tls_fallback: function read_tls_fallback missing Go declaration

src/cmd/vet/all/whitelist/ppc64x.txt

 // ppc64-specific vet whitelist. See readme.txt for details.
 
-internal/bytealg/compare_ppc64x.s: [GOARCH] cannot check cross-package assembly function: cmpstring is in package runtime
-
 runtime/asm_ppc64x.s: [GOARCH] reginit: function reginit missing Go declaration
 runtime/asm_ppc64x.s: [GOARCH] goexit: use of 24(R1) points beyond argument frame
 runtime/asm_ppc64x.s: [GOARCH] addmoduledata: function addmoduledata missing Go declaration

src/cmd/vet/all/whitelist/s390x.txt

-internal/bytealg/compare_s390x.s: [s390x] cannot check cross-package assembly function: cmpstring is in package runtime
 runtime/asm_s390x.s: [s390x] addmoduledata: function addmoduledata missing Go declaration
 runtime/memclr_s390x.s: [s390x] memclr_s390x_exrl_xc: function memclr_s390x_exrl_xc missing Go declaration
 runtime/memmove_s390x.s: [s390x] memmove_s390x_exrl_mvc: function memmove_s390x_exrl_mvc missing Go declaration
 runtime/tls_s390x.s: [s390x] save_g: function save_g missing Go declaration
 runtime/tls_s390x.s: [s390x] load_g: function load_g missing Go declaration
-internal/cpu/cpu_s390x.s: [s390x] stfle: invalid MOVD of ret+0(FP); cpu.facilityList is 32-byte value
-internal/cpu/cpu_s390x.s: [s390x] kmQuery: invalid MOVD of ret+0(FP); cpu.queryResult is 16-byte value
-internal/cpu/cpu_s390x.s: [s390x] kmcQuery: invalid MOVD of ret+0(FP); cpu.queryResult is 16-byte value
-internal/cpu/cpu_s390x.s: [s390x] kmctrQuery: invalid MOVD of ret+0(FP); cpu.queryResult is 16-byte value
-internal/cpu/cpu_s390x.s: [s390x] kmaQuery: invalid MOVD of ret+0(FP); cpu.queryResult is 16-byte value
-internal/cpu/cpu_s390x.s: [s390x] kimdQuery: invalid MOVD of ret+0(FP); cpu.queryResult is 16-byte value
-internal/cpu/cpu_s390x.s: [s390x] klmdQuery: invalid MOVD of ret+0(FP); cpu.queryResult is 16-byte value
+internal/cpu/cpu_s390x.s: [s390x] stfle: invalid MOVD of ret+0(FP); internal/cpu.facilityList is 32-byte value
+internal/cpu/cpu_s390x.s: [s390x] kmQuery: invalid MOVD of ret+0(FP); internal/cpu.queryResult is 16-byte value
+internal/cpu/cpu_s390x.s: [s390x] kmcQuery: invalid MOVD of ret+0(FP); internal/cpu.queryResult is 16-byte value
+internal/cpu/cpu_s390x.s: [s390x] kmctrQuery: invalid MOVD of ret+0(FP); internal/cpu.queryResult is 16-byte value
+internal/cpu/cpu_s390x.s: [s390x] kmaQuery: invalid MOVD of ret+0(FP); internal/cpu.queryResult is 16-byte value
+internal/cpu/cpu_s390x.s: [s390x] kimdQuery: invalid MOVD of ret+0(FP); internal/cpu.queryResult is 16-byte value
+internal/cpu/cpu_s390x.s: [s390x] klmdQuery: invalid MOVD of ret+0(FP); internal/cpu.queryResult is 16-byte value

src/cmd/vet/all/whitelist/wasm.txt

@@ -2,9 +2,6 @@
 
 // False positives.
 
-// Nothing much to do about cross-package assembly. Unfortunate.
-internal/bytealg/compare_wasm.s: [wasm] cannot check cross-package assembly function: cmpstring is in package runtime
-
 // morestack intentionally omits arg size.
 runtime/asm_wasm.s: [wasm] morestack: use of 8(SP) points beyond argument frame
 runtime/asm_wasm.s: [wasm] morestack: use of 16(SP) points beyond argument frame

src/cmd/vet/all/whitelist/windows_386.txt

@@ -6,4 +6,3 @@ runtime/sys_windows_386.s: [386] setldt: function setldt missing Go declaration
 runtime/sys_windows_386.s: [386] callbackasm1+0: function callbackasm1+0 missing Go declaration
 runtime/sys_windows_386.s: [386] tstart: function tstart missing Go declaration
 runtime/sys_windows_386.s: [386] tstart_stdcall: RET without writing to 4-byte ret+4(FP)
-runtime/sys_windows_386.s: [386] cannot check cross-package assembly function: now is in package time

src/cmd/vet/all/whitelist/windows_amd64.txt

@@ -5,4 +5,3 @@ runtime/sys_windows_amd64.s: [amd64] ctrlhandler: RET without writing to 4-byte
 runtime/sys_windows_amd64.s: [amd64] callbackasm1: function callbackasm1 missing Go declaration
 runtime/sys_windows_amd64.s: [amd64] tstart_stdcall: RET without writing to 4-byte ret+8(FP)
 runtime/sys_windows_amd64.s: [amd64] settls: function settls missing Go declaration
-runtime/sys_windows_amd64.s: [amd64] cannot check cross-package assembly function: now is in package time