From 56a1fd0257864c54b80ff760c46f3463b6fd2f9c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Mart=C3=AD?= <mvdan@mvdan.cc>
Date: Mon, 25 May 2020 21:41:23 +0100
Subject: [PATCH 1/3] support -ldflags=-X=pkg.name=str with garbled names
Because the linker has access to all the build IDs, just like the
compiler, we can support this transparently. Add a test too.
Fixes #21.
---
main.go | 64 ++++++++++++++++++++++++++++++++----
testdata/scripts/ldflags.txt | 36 ++++++++++++++++++++
2 files changed, 94 insertions(+), 6 deletions(-)
create mode 100644 testdata/scripts/ldflags.txt
diff --git a/main.go b/main.go
index 53ae290..1d2ce03 100644
--- a/main.go
+++ b/main.go
@@ -112,8 +112,10 @@ func garbledImport(path string) (*types.Package, error) {
}
type packageInfo struct {
- buildID string
- imports map[string]importedPkg
+ buildID string // from -buildid
+
+ imports map[string]importedPkg // from -importcfg
+ firstImport string // first from -importcfg; the main package when linking
}
type importedPkg struct {
@@ -310,6 +312,7 @@ func transformCompile(args []string) ([]string, error) {
deferred = append(deferred, func() error {
return os.RemoveAll(tempDir)
})
+
// Add our temporary dir to the beginning of -trimpath, so that we don't
// leak temporary dirs. Needs to be at the beginning, since there may be
// shorter prefixes later in the list, such as $PWD if TMPDIR=$PWD/tmp.
@@ -354,6 +357,8 @@ func transformCompile(args []string) ([]string, error) {
func isPrivate(pkgPath string) bool {
if pkgPath == "main" {
// TODO: why don't we see the full package path for main packages?
+ // Hint: it seems like the real import path is at the top of
+ // -importcfg.
return true
}
return GlobsMatchPath(envGoPrivate, pkgPath)
@@ -396,6 +401,9 @@ func readBuildIDs(flags []string) error {
if err != nil {
return err
}
+ if len(buildInfo.imports) == 0 {
+ buildInfo.firstImport = importPath
+ }
buildInfo.imports[importPath] = importedPkg{
packagefile: objectPath,
buildID: fileID,
@@ -587,6 +595,39 @@ func transformLink(args []string) ([]string, error) {
// Nothing to transform; probably just ["-V=full"].
return args, nil
}
+
+ // Make sure -X works with garbled identifiers. To cover both garbled
+ // and non-garbled names, duplicate each flag with a garbled version.
+ if err := readBuildIDs(flags); err != nil {
+ return nil, err
+ }
+ flagValueIter(flags, "-X", func(val string) {
+ // val is in the form of "pkg.name=str"
+ i := strings.IndexByte(val, '=')
+ if i <= 0 {
+ return
+ }
+ name := val[:i]
+ str := val[i+1:]
+ j := strings.IndexByte(name, '.')
+ if j <= 0 {
+ return
+ }
+ pkg := name[:j]
+ name = name[j+1:]
+
+ pkgPath := pkg
+ if pkgPath == "main" {
+ // The main package is known under its import path in
+ // the import config map.
+ pkgPath = buildInfo.firstImport
+ }
+ if id := buildInfo.imports[pkgPath].buildID; id != "" {
+ name = hashWith(id, name)
+ flags = append(flags, fmt.Sprintf("-X=%s.%s=%s", pkg, name, str))
+ }
+ })
+
flags = append(flags, "-w", "-s")
return append(flags, paths...), nil
}
@@ -605,21 +646,32 @@ func splitFlagsFromFiles(args []string, ext string) (flags, paths []string) {
}
// flagValue retrieves the value of a flag such as "-foo", from strings in the
-// list of arguments like "-foo=bar" or "-foo" "bar".
+// list of arguments like "-foo=bar" or "-foo" "bar". If the flag is repeated,
+// the last value is returned.
func flagValue(flags []string, name string) string {
+ lastVal := ""
+ flagValueIter(flags, name, func(val string) {
+ lastVal = val
+ })
+ return lastVal
+}
+
+// flagValueIter retrieves all the values for a flag such as "-foo", like
+// flagValue. The difference is that it allows handling complex flags, such as
+// those whose values compose a list.
+func flagValueIter(flags []string, name string, fn func(string)) {
for i, arg := range flags {
if val := strings.TrimPrefix(arg, name+"="); val != arg {
// -name=value
- return val
+ fn(val)
}
if arg == name { // -name ...
if i+1 < len(flags) {
// -name value
- return flags[i+1]
+ fn(flags[i+1])
}
}
}
- return ""
}
func flagSetValue(flags []string, name, value string) []string {
diff --git a/testdata/scripts/ldflags.txt b/testdata/scripts/ldflags.txt
new file mode 100644
index 0000000..370ee2e
--- /dev/null
+++ b/testdata/scripts/ldflags.txt
@@ -0,0 +1,36 @@
+garble build -ldflags='-X=main.unexportedVersion=v1.0.0 -X=test/main/imported.ExportedVar=replaced'
+exec ./main
+cmp stdout main.stdout
+! binsubstr main$exe 'unexportedVersion'
+
+[short] stop # no need to verify this with -short
+
+exec go build -ldflags='-X=main.unexportedVersion=v1.0.0 -X=test/main/imported.ExportedVar=replaced'
+exec ./main
+cmp stdout main.stdout
+binsubstr main$exe 'unexportedVersion'
+
+-- go.mod --
+module test/main
+-- main.go --
+package main
+
+import (
+ "fmt"
+
+ "test/main/imported"
+)
+
+var unexportedVersion = "unknown"
+
+func main() {
+ fmt.Println("version:", unexportedVersion)
+ fmt.Println("var:", imported.ExportedVar)
+}
+-- imported/imported.go --
+package imported
+
+var ExportedVar = "original"
+-- main.stdout --
+version: v1.0.0
+var: replaced
From e4b58b14523cc20c2a9eba3c974bd50a0c0067a4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Mart=C3=AD?= <mvdan@mvdan.cc>
Date: Mon, 25 May 2020 22:07:41 +0100
Subject: [PATCH 2/3] reduce unnecessary std imports in tests
Since we have to recompile all dependencies, this reduces a substantial
amount of work, reducing 'go test -short' time from ~16s to ~12s on my
laptop.
---
testdata/scripts/asm.txt | 12 +++++-------
testdata/scripts/cgo.txt | 10 ++++------
testdata/scripts/ldflags.txt | 12 +++++-------
testdata/scripts/modinfo.txt | 23 ++++++++++++-----------
testdata/scripts/plugin.txt | 10 ++++------
5 files changed, 30 insertions(+), 37 deletions(-)
diff --git a/testdata/scripts/asm.txt b/testdata/scripts/asm.txt
index 65ee650..05b842b 100644
--- a/testdata/scripts/asm.txt
+++ b/testdata/scripts/asm.txt
@@ -1,13 +1,13 @@
garble build
exec ./main
-cmp stdout main.stdout
+cmp stderr main.stderr
binsubstr main$exe 'privateAdd' 'PublicAdd'
[short] stop # no need to verify this with -short
go build
exec ./main
-cmp stdout main.stdout
+cmp stderr main.stderr
-- go.mod --
module test/main
@@ -15,16 +15,14 @@ module test/main
package main
import (
- "fmt"
-
"test/main/imported"
)
func privateAdd(x, y int64) int64
func main() {
- fmt.Println(privateAdd(1, 2))
- fmt.Println(imported.PublicAdd(3, 4))
+ println(privateAdd(1, 2))
+ println(imported.PublicAdd(3, 4))
}
-- main.s --
TEXT ·privateAdd(SB),$0-24
@@ -44,6 +42,6 @@ TEXT ·PublicAdd(SB),$0-24
ADDQ BP, BX
MOVQ BX, ret+16(FP)
RET
--- main.stdout --
+-- main.stderr --
3
7
diff --git a/testdata/scripts/cgo.txt b/testdata/scripts/cgo.txt
index 2d41ea2..370a410 100644
--- a/testdata/scripts/cgo.txt
+++ b/testdata/scripts/cgo.txt
@@ -1,13 +1,13 @@
garble build
exec ./main
-cmp stdout main.stdout
+cmp stderr main.stderr
binsubstr main$exe 'privateAdd'
[short] stop # no need to verify this with -short
go build
exec ./main
-cmp stdout main.stdout
+cmp stderr main.stderr
-- go.mod --
module test/main
@@ -21,10 +21,8 @@ static int privateAdd(int a, int b) {
*/
import "C"
-import "fmt"
-
func main() {
- fmt.Println(C.privateAdd(C.int(1), C.int(2)))
+ println(C.privateAdd(C.int(1), C.int(2)))
}
--- main.stdout --
+-- main.stderr --
3
diff --git a/testdata/scripts/ldflags.txt b/testdata/scripts/ldflags.txt
index 370ee2e..170b3be 100644
--- a/testdata/scripts/ldflags.txt
+++ b/testdata/scripts/ldflags.txt
@@ -1,13 +1,13 @@
garble build -ldflags='-X=main.unexportedVersion=v1.0.0 -X=test/main/imported.ExportedVar=replaced'
exec ./main
-cmp stdout main.stdout
+cmp stderr main.stderr
! binsubstr main$exe 'unexportedVersion'
[short] stop # no need to verify this with -short
exec go build -ldflags='-X=main.unexportedVersion=v1.0.0 -X=test/main/imported.ExportedVar=replaced'
exec ./main
-cmp stdout main.stdout
+cmp stderr main.stderr
binsubstr main$exe 'unexportedVersion'
-- go.mod --
@@ -16,21 +16,19 @@ module test/main
package main
import (
- "fmt"
-
"test/main/imported"
)
var unexportedVersion = "unknown"
func main() {
- fmt.Println("version:", unexportedVersion)
- fmt.Println("var:", imported.ExportedVar)
+ println("version:", unexportedVersion)
+ println("var:", imported.ExportedVar)
}
-- imported/imported.go --
package imported
var ExportedVar = "original"
--- main.stdout --
+-- main.stderr --
version: v1.0.0
var: replaced
diff --git a/testdata/scripts/modinfo.txt b/testdata/scripts/modinfo.txt
index f99e963..91d58d4 100644
--- a/testdata/scripts/modinfo.txt
+++ b/testdata/scripts/modinfo.txt
@@ -1,13 +1,13 @@
garble build
exec ./main
-cmp stdout main.stdout
+cmp stderr main.stderr
! binsubstr main$exe '(devel)'
[short] stop # no need to verify this with -short
exec go build
exec ./main
-cmp stdout main.stdout-orig
+cmp stderr main.stderr-orig
binsubstr main$exe '(devel)'
-- go.mod --
@@ -15,15 +15,16 @@ module test/main
-- main.go --
package main
-import (
- "fmt"
- "runtime/debug"
-)
+import "runtime/debug"
func main() {
- fmt.Println(debug.ReadBuildInfo())
+ if info, ok := debug.ReadBuildInfo(); ok {
+ println("version", info.Main.Version)
+ } else {
+ println("no version")
+ }
}
--- main.stdout-orig --
-&{test/main {test/main (devel) <nil>} []} true
--- main.stdout --
-<nil> false
+-- main.stderr-orig --
+version (devel)
+-- main.stderr --
+no version
diff --git a/testdata/scripts/plugin.txt b/testdata/scripts/plugin.txt
index 9d31966..4bf782d 100644
--- a/testdata/scripts/plugin.txt
+++ b/testdata/scripts/plugin.txt
@@ -7,7 +7,7 @@ binsubstr plugin.so 'PublicVar' 'PublicFunc'
# Note that we need -trimpath; see the caveat section in the README.
go build -trimpath
exec ./main
-cmp stdout main.stdout
+cmp stderr main.stderr
binsubstr main$exe 'PublicVar' 'PublicFunc'
! binsubstr plugin.so 'privateFunc'
@@ -17,18 +17,16 @@ go build -buildmode=plugin ./plugin
binsubstr plugin.so 'PublicVar' 'PublicFunc' 'privateFunc'
go build
exec ./main
-cmp stdout main.stdout
+cmp stderr main.stderr
-- go.mod --
module test/main
-- plugin/main.go --
package main
-import "fmt"
-
var PublicVar int
-func privateFunc(n int) { fmt.Printf("Hello, number %d\n", n) }
+func privateFunc(n int) { println("Hello, number", n) }
func PublicFunc() { privateFunc(PublicVar) }
-- main.go --
@@ -52,5 +50,5 @@ func main() {
*v.(*int) = 7
f.(func())()
}
--- main.stdout --
+-- main.stderr --
Hello, number 7
From e8074d46652afc869678aa71c1b999198245e1b0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Mart=C3=AD?= <mvdan@mvdan.cc>
Date: Mon, 25 May 2020 22:27:09 +0100
Subject: [PATCH 3/3] support building ad-hoc plugin packages
That is, plugin packages by source file names, not by package path.
Fixes #19.
---
main.go | 8 ++++----
testdata/scripts/plugin.txt | 12 +++++++++++-
2 files changed, 15 insertions(+), 5 deletions(-)
diff --git a/main.go b/main.go
index 1d2ce03..5e9f950 100644
--- a/main.go
+++ b/main.go
@@ -355,10 +355,10 @@ func transformCompile(args []string) ([]string, error) {
// To allow using garble without GOPRIVATE for standalone main packages, it will
// default to not matching standard library packages.
func isPrivate(pkgPath string) bool {
- if pkgPath == "main" {
- // TODO: why don't we see the full package path for main packages?
- // Hint: it seems like the real import path is at the top of
- // -importcfg.
+ if pkgPath == "main" || strings.HasPrefix(pkgPath, "plugin/unnamed") {
+ // TODO: why don't we see the full package path for main
+ // packages? The linker has it at the top of -importcfg, but not
+ // the compiler.
return true
}
return GlobsMatchPath(envGoPrivate, pkgPath)
diff --git a/testdata/scripts/plugin.txt b/testdata/scripts/plugin.txt
index 4bf782d..9271f48 100644
--- a/testdata/scripts/plugin.txt
+++ b/testdata/scripts/plugin.txt
@@ -13,6 +13,10 @@ binsubstr main$exe 'PublicVar' 'PublicFunc'
[short] stop # no need to verify this with -short
+# This used to fail, since in this case the package path for the ad-hoc plugin
+# package isn't "main", but "plugin/unnamed-*".
+garble build -buildmode=plugin plugin/main.go
+
go build -buildmode=plugin ./plugin
binsubstr plugin.so 'PublicVar' 'PublicFunc' 'privateFunc'
go build
@@ -24,11 +28,17 @@ module test/main
-- plugin/main.go --
package main
-var PublicVar int
+import "test/main/plugin/lib"
+
+var PublicVar int = lib.ImportedFunc()
func privateFunc(n int) { println("Hello, number", n) }
func PublicFunc() { privateFunc(PublicVar) }
+-- plugin/lib/lib.go --
+package lib
+
+func ImportedFunc() int { return 4 }
-- main.go --
package main