cmd/go: move runtime/debug.modinfo to runtime.modinfo
It is easier to ensure that the symbol is always present
if we move it to package runtime. Avoids init-time work.
Also moves it next to buildVersion, the other similar symbol.
Setting up for "go version <binary>".
For #31624.
Change-Id: I943724469ce6992153e701257eb6f12da88c8e4e
Reviewed-on: https://go-review.googlesource.com/c/go/+/173341
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
diff --git a/src/cmd/go/internal/modload/build.go b/src/cmd/go/internal/modload/build.go
index 25303ce..a41b176 100644
--- a/src/cmd/go/internal/modload/build.go
+++ b/src/cmd/go/internal/modload/build.go
@@ -247,21 +247,15 @@
}
func ModInfoProg(info string) []byte {
- // Inject a variable with the debug information as runtime/debug.modinfo,
+ // Inject a variable with the debug information as runtime.modinfo,
// but compile it in package main so that it is specific to the binary.
- //
// The variable must be a literal so that it will have the correct value
// before the initializer for package main runs.
//
- // We also want the value to be present even if runtime/debug.modinfo is
- // otherwise unused in the rest of the program. Reading it in an init function
- // suffices for now.
-
+ // The runtime startup code refers to the variable, which keeps it live in all binaries.
return []byte(fmt.Sprintf(`package main
import _ "unsafe"
-//go:linkname __debug_modinfo__ runtime/debug.modinfo
+//go:linkname __debug_modinfo__ runtime.modinfo
var __debug_modinfo__ = %q
-var keepalive_modinfo = __debug_modinfo__
-func init() { keepalive_modinfo = __debug_modinfo__ }
`, string(infoStart)+info+string(infoEnd)))
}
diff --git a/src/runtime/debug.go b/src/runtime/debug.go
index 06bf0fa..af5c3a1 100644
--- a/src/runtime/debug.go
+++ b/src/runtime/debug.go
@@ -57,3 +57,8 @@
func NumGoroutine() int {
return int(gcount())
}
+
+//go:linkname debug_modinfo runtime/debug.modinfo
+func debug_modinfo() string {
+ return modinfo
+}
diff --git a/src/runtime/debug/mod.go b/src/runtime/debug/mod.go
index 2c5aa27..e3b929a 100644
--- a/src/runtime/debug/mod.go
+++ b/src/runtime/debug/mod.go
@@ -8,14 +8,14 @@
"strings"
)
-// set using cmd/go/internal/modload.ModInfoProg
-var modinfo string
+// exported from runtime
+func modinfo() string
// ReadBuildInfo returns the build information embedded
// in the running binary. The information is available only
// in binaries built with module support.
func ReadBuildInfo() (info *BuildInfo, ok bool) {
- return readBuildInfo(modinfo)
+ return readBuildInfo(modinfo())
}
// BuildInfo represents the build information read from
diff --git a/src/runtime/proc.go b/src/runtime/proc.go
index 57ad17d..e94de3a 100644
--- a/src/runtime/proc.go
+++ b/src/runtime/proc.go
@@ -13,6 +13,9 @@
var buildVersion = sys.TheVersion
+// set using cmd/go/internal/modload.ModInfoProg
+var modinfo string
+
// Goroutine scheduler
// The scheduler's job is to distribute ready-to-run goroutines over worker threads.
//
@@ -577,6 +580,11 @@
// to ensure runtime·buildVersion is kept in the resulting binary.
buildVersion = "unknown"
}
+ if len(modinfo) == 1 {
+ // Condition should never trigger. This code just serves
+ // to ensure runtime·modinfo is kept in the resulting binary.
+ modinfo = ""
+ }
}
func dumpgstatus(gp *g) {
