cmd/cgo: use objdir consistently, create it as needed

Previously we added a slash to the end of objdir only after
processing input files. The effect was that the temporary gcc
output files were placed in /tmp, using objdir as a prefix.
Those output files were not removed by anything.

Now we consistently use objdir as a directory, not a prefix.
We only create it when needed; there is already a test for that in
cmd/go/testdata/script/build_cwd_newline.txt.

Change-Id: Ie66d9c04ecc3c0f5950fc1111c74e1d01c67304c
Reviewed-on: https://go-review.googlesource.com/c/go/+/740742
Auto-Submit: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Roland Shoemaker <roland@golang.org>
Reviewed-by: David Chase <drchase@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

diff --git a/src/cmd/cgo/gcc.go b/src/cmd/cgo/gcc.go
index 300ccae350b44db48fd862ab9447816b46e78123..b8b8d6baec65543f239ccacf88d4ec8919a80ebb 100644 (file)
--- a/src/cmd/cgo/gcc.go
+++ b/src/cmd/cgo/gcc.go
@@ -24,6 +24,7 @@ import (
        "math"
        "os"
        "os/exec"
+       "path/filepath"
        "slices"
        "strconv"
        "strings"
@@ -1795,7 +1796,7 @@ var n atomic.Int64
 
 func gccTmp() string {
        c := strconv.Itoa(int(n.Add(1)))
-       return *objDir + "_cgo_" + c + ".o"
+       return filepath.Join(outputDir(), "_cgo_"+c+".o")
 }
 
 // gccCmd returns the gcc command line to use for compiling

diff --git a/src/cmd/cgo/main.go b/src/cmd/cgo/main.go
index ba8e52a6e0232e03cbebe93645d49a5f42ecb5f8..452840a4cfbb1918c3275cb32f7f3fd01978053a 100644 (file)
--- a/src/cmd/cgo/main.go
+++ b/src/cmd/cgo/main.go
@@ -320,6 +320,10 @@ func main() {
                conf.Mode &^= printer.SourcePos
        }
 
+       if *objDir == "" {
+               *objDir = "_obj"
+       }
+
        args := flag.Args()
        if len(args) < 1 {
                usage()
@@ -446,14 +450,6 @@ func main() {
 
        cPrefix = fmt.Sprintf("_%x", h.Sum(nil)[0:6])
 
-       if *objDir == "" {
-               *objDir = "_obj"
-       }
-       // make sure that `objDir` directory exists, so that we can write
-       // all the output files there.
-       os.MkdirAll(*objDir, 0o700)
-       *objDir += string(filepath.Separator)
-
        for i, input := range goFiles {
                f := fs[i]
                p.Translate(f)

diff --git a/src/cmd/cgo/out.go b/src/cmd/cgo/out.go
index ac2ce8fd0dce3b30415cf4c2171c40763a1069f1..151000f5813c3d9ef0f6245c9ca7736f4b03b1f4 100644 (file)
--- a/src/cmd/cgo/out.go
+++ b/src/cmd/cgo/out.go
@@ -33,15 +33,15 @@ var (
 // writeDefs creates output files to be compiled by gc and gcc.
 func (p *Package) writeDefs() {
        var fgo2, fc io.Writer
-       f := creat(*objDir + "_cgo_gotypes.go")
+       f := creat("_cgo_gotypes.go")
        defer f.Close()
        fgo2 = f
        if *gccgo {
-               f := creat(*objDir + "_cgo_defun.c")
+               f := creat("_cgo_defun.c")
                defer f.Close()
                fc = f
        }
-       fm := creat(*objDir + "_cgo_main.c")
+       fm := creat("_cgo_main.c")
 
        var gccgoInit strings.Builder
 
@@ -50,7 +50,7 @@ func (p *Package) writeDefs() {
                        fmt.Fprintf(fgo2, "//go:cgo_ldflag %q\n", arg)
                }
        } else {
-               fflg := creat(*objDir + "_cgo_flags")
+               fflg := creat("_cgo_flags")
                for _, arg := range p.LdFlags {
                        fmt.Fprintf(fflg, "_CGO_LDFLAGS=%s\n", arg)
                }
@@ -242,8 +242,8 @@ func (p *Package) writeDefs() {
                }
        }
 
-       fgcc := creat(*objDir + "_cgo_export.c")
-       fgcch := creat(*objDir + "_cgo_export.h")
+       fgcc := creat("_cgo_export.c")
+       fgcch := creat("_cgo_export.h")
        if *gccgo {
                p.writeGccgoExports(fgo2, fm, fgcc, fgcch)
        } else {
@@ -263,8 +263,11 @@ func (p *Package) writeDefs() {
        }
 
        if *exportHeader != "" && len(p.ExpFunc) > 0 {
-               fexp := creat(*exportHeader)
-               fgcch, err := os.Open(*objDir + "_cgo_export.h")
+               fexp, err := os.Create(*exportHeader)
+               if err != nil {
+                       fatalf("%s", err)
+               }
+               fgcch, err := os.Open(filepath.Join(outputDir(), "_cgo_export.h"))
                if err != nil {
                        fatalf("%s", err)
                }
@@ -697,8 +700,8 @@ func (p *Package) writeOutput(f *File, srcfile string) {
        base := srcfile
        base = strings.TrimSuffix(base, ".go")
        base = filepath.Base(base)
-       fgo1 := creat(*objDir + base + ".cgo1.go")
-       fgcc := creat(*objDir + base + ".cgo2.c")
+       fgo1 := creat(base + ".cgo1.go")
+       fgcc := creat(base + ".cgo2.c")
 
        p.GoFiles = append(p.GoFiles, base+".cgo1.go")
        p.GccFiles = append(p.GccFiles, base+".cgo2.c")
@@ -1395,7 +1398,7 @@ func gccgoToSymbol(ppath string) string {
                                fatalf("unable to locate gccgo: %v", err)
                        }
                }
-               gccgoMangler, err = pkgpath.ToSymbolFunc(cmd, *objDir)
+               gccgoMangler, err = pkgpath.ToSymbolFunc(cmd, outputDir())
                if err != nil {
                        fatalf("%v", err)
                }

diff --git a/src/cmd/cgo/util.go b/src/cmd/cgo/util.go
index e83634ffb222a0cb2178a9f5776cd347694191fc..bf34d61e902dcaa931d60b2f0dde8d10c034b8e1 100644 (file)
--- a/src/cmd/cgo/util.go
+++ b/src/cmd/cgo/util.go
@@ -10,6 +10,7 @@ import (
        "go/token"
        "os"
        "os/exec"
+       "path/filepath"
        "slices"
 )
 
@@ -97,10 +98,17 @@ func error_(pos token.Pos, msg string, args ...any) {
        fmt.Fprintf(os.Stderr, "\n")
 }
 
+// create creates a file in the output directory.
 func creat(name string) *os.File {
-       f, err := os.Create(name)
+       f, err := os.Create(filepath.Join(outputDir(), name))
        if err != nil {
                fatalf("%s", err)
        }
        return f
 }
+
+// outputDir returns the output directory, making sure that it exists.
+func outputDir() string {
+       os.MkdirAll(*objDir, 0o700)
+       return *objDir
+}