cmd/trace: make binary argument optional

1.7 traces embed symbol info and we now generate symbolized pprof profiles,
so we don't need the binary. Make binary argument optional as 1.5 traces
still need it.

Change-Id: I65eb13e3d20ec765acf85c42d42a8d7aae09854c
Reviewed-on: https://go-review.googlesource.com/22410
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
Reviewed-by: Austin Clements <austin@google.com>

diff --git a/src/cmd/go/test.go b/src/cmd/go/test.go
index 5c21de5d9ba558696ea3edffd20b738a6840f0e3..02abcbe23a07f063fe761465728b5baa63655962 100644 (file)
--- a/src/cmd/go/test.go
+++ b/src/cmd/go/test.go
@@ -233,7 +233,6 @@ const testFlag2 = `
 
        -trace trace.out
            Write an execution trace to the specified file before exiting.
-           Writes test binary as -c would.
 
        -v
            Verbose output: log all tests as they are run. Also print all

diff --git a/src/cmd/go/testflag.go b/src/cmd/go/testflag.go
index 873df1ffc36ce7434f2022fb35bfa6d4e1371e3c..a65ed1f3840293c4df906664b50121cd4a98357e 100644 (file)
--- a/src/cmd/go/testflag.go
+++ b/src/cmd/go/testflag.go
@@ -149,9 +149,11 @@ func testFlags(args []string) (packageNames, passToTest []string) {
                                testBench = true
                        case "timeout":
                                testTimeout = value
-                       case "blockprofile", "cpuprofile", "memprofile", "trace":
+                       case "blockprofile", "cpuprofile", "memprofile":
                                testProfile = true
                                testNeedBinary = true
+                       case "trace":
+                               testProfile = true
                        case "coverpkg":
                                testCover = true
                                if value == "" {

diff --git a/src/cmd/trace/main.go b/src/cmd/trace/main.go
index cfd222e132afe899ac87124cace7e59e531a602f..2735bf13ea23e99d816c239c438c0317f38cf774 100644 (file)
--- a/src/cmd/trace/main.go
+++ b/src/cmd/trace/main.go
@@ -14,7 +14,7 @@ Example usage:
 Generate a trace file with 'go test':
        go test -trace trace.out pkg
 View the trace in a web browser:
-       go tool trace pkg.test trace.out
+       go tool trace trace.out
 */
 package main
 
@@ -37,7 +37,9 @@ Given a trace file produced by 'go test':
        go test -trace=trace.out pkg
 
 Open a web browser displaying trace:
-       go tool trace [flags] pkg.test trace.out
+       go tool trace [flags] [pkg.test] trace.out
+[pkg.test] argument is required for traces produced by Go 1.6 and below.
+Go 1.7 does not require the binary argument.
 
 Flags:
        -http=addr: HTTP service address (e.g., ':6060')
@@ -58,12 +60,17 @@ func main() {
        }
        flag.Parse()
 
-       // Usage information when no arguments.
-       if flag.NArg() != 2 {
+       // Go 1.7 traces embed symbol info and does not require the binary.
+       // But we optionally accept binary as first arg for Go 1.5 traces.
+       switch flag.NArg() {
+       case 1:
+               traceFile = flag.Arg(0)
+       case 2:
+               programBinary = flag.Arg(0)
+               traceFile = flag.Arg(1)
+       default:
                flag.Usage()
        }
-       programBinary = flag.Arg(0)
-       traceFile = flag.Arg(1)
 
        ln, err := net.Listen("tcp", *httpFlag)
        if err != nil {
@@ -91,7 +98,7 @@ var loader struct {
 
 func parseEvents() ([]*trace.Event, error) {
        loader.once.Do(func() {
-               tracef, err := os.Open(flag.Arg(1))
+               tracef, err := os.Open(traceFile)
                if err != nil {
                        loader.err = fmt.Errorf("failed to open trace file: %v", err)
                        return