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cgo2: refactor for readability #3771

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cgo2: refactor for readability #3771

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133 changes: 76 additions & 57 deletions go/tools/builders/cgo2.go
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Original file line number Diff line number Diff line change
Expand Up @@ -23,22 +23,41 @@ package main
import (
"bytes"
"fmt"
"io/ioutil"
"io"
"os"
"path/filepath"
"strings"
)

// cgo2 processes a set of mixed source files with cgo.
func cgo2(goenv *env, goSrcs, cgoSrcs, cSrcs, cxxSrcs, objcSrcs, objcxxSrcs, sSrcs, hSrcs []string, packagePath, packageName string, cc string, cppFlags, cFlags, cxxFlags, objcFlags, objcxxFlags, ldFlags []string, cgoExportHPath string) (srcDir string, allGoSrcs, cObjs []string, err error) {
type sourceFiles struct {
goSrcs, cgo []string
c, cxx []string
objc, objcxx []string
s, h []string
}

type ccToolchain struct {
cc string
cppFlags, cFlags, cxxFlags, objcFlags, objcxxFlags, ldFlags []string
}

type cgoOption struct {
packagePath, packageName string
cgoExportHPath string
source *sourceFiles
ccToolchain *ccToolchain
}

// cgo processes a set of mixed source files with cgo.
func cgo(goenv *env, opt *cgoOption) (srcDir string, allGoSrcs, cObjs []string, err error) {
// Report an error if the C/C++ toolchain wasn't configured.
if cc == "" {
err := cgoError(cgoSrcs[:])
err = append(err, cSrcs...)
err = append(err, cxxSrcs...)
err = append(err, objcSrcs...)
err = append(err, objcxxSrcs...)
err = append(err, sSrcs...)
if opt.ccToolchain.cc == "" {
err := cgoError(opt.source.cgo[:])
err = append(err, opt.source.c...)
err = append(err, opt.source.cxx...)
err = append(err, opt.source.objc...)
err = append(err, opt.source.objcxx...)
err = append(err, opt.source.s...)
return "", nil, nil, err
}

Expand All @@ -48,8 +67,8 @@ func cgo2(goenv *env, goSrcs, cgoSrcs, cSrcs, cxxSrcs, objcSrcs, objcxxSrcs, sSr
// TODO(jayconrod): this doesn't write CGO_LDFLAGS into the archive. We
// might miss dependencies like -lstdc++ if they aren't referenced in
// some other way.
if len(cgoSrcs) == 0 {
cObjs, err = compileCSources(goenv, cSrcs, cxxSrcs, objcSrcs, objcxxSrcs, sSrcs, hSrcs, cc, cppFlags, cFlags, cxxFlags, objcFlags, objcxxFlags)
if len(opt.source.cgo) == 0 {
cObjs, err = compileCSources(goenv, opt.source, opt.ccToolchain)
return ".", nil, cObjs, err
}

Expand All @@ -63,7 +82,7 @@ func cgo2(goenv *env, goSrcs, cgoSrcs, cSrcs, cxxSrcs, objcSrcs, objcxxSrcs, sSr
// scanners might want to include or exclude these sources we need to ensure
// that a fragment of the path is stable and human friendly enough to be
// referenced in nogo configuration.
workDir = filepath.Join(workDir, "cgo", packagePath)
workDir = filepath.Join(workDir, "cgo", opt.packagePath)
if err := os.MkdirAll(workDir, 0700); err != nil {
return "", nil, nil, err
}
Expand All @@ -72,9 +91,9 @@ func cgo2(goenv *env, goSrcs, cgoSrcs, cSrcs, cxxSrcs, objcSrcs, objcxxSrcs, sSr
// and set CGO_LDFLAGS. These flags get written as special comments into cgo
// generated sources. The compiler encodes those flags in the compiled .a
// file, and the linker passes them on to the external linker.
haveCxx := len(cxxSrcs)+len(objcxxSrcs) > 0
haveCxx := len(opt.source.cxx)+len(opt.source.objcxx) > 0
if !haveCxx {
for _, f := range ldFlags {
for _, f := range opt.ccToolchain.ldFlags {
if strings.HasSuffix(f, ".a") {
// These flags come from cdeps options. Assume C++.
haveCxx = true
Expand All @@ -84,9 +103,9 @@ func cgo2(goenv *env, goSrcs, cgoSrcs, cSrcs, cxxSrcs, objcSrcs, objcxxSrcs, sSr
}
var combinedLdFlags []string
if haveCxx {
combinedLdFlags = append(combinedLdFlags, ldFlags...)
combinedLdFlags = append(combinedLdFlags, opt.ccToolchain.ldFlags...)
} else {
for _, f := range ldFlags {
for _, f := range opt.ccToolchain.ldFlags {
if f != "-lc++" && f != "-lstdc++" {
combinedLdFlags = append(combinedLdFlags, f)
}
Expand All @@ -97,35 +116,35 @@ func cgo2(goenv *env, goSrcs, cgoSrcs, cSrcs, cxxSrcs, objcSrcs, objcxxSrcs, sSr

// If cgo sources are in different directories, gather them into a temporary
// directory so we can use -srcdir.
srcDir = filepath.Dir(cgoSrcs[0])
srcDir = filepath.Dir(opt.source.cgo[0])
srcsInSingleDir := true
for _, src := range cgoSrcs[1:] {
for _, src := range opt.source.cgo[1:] {
if filepath.Dir(src) != srcDir {
srcsInSingleDir = false
break
}
}

if srcsInSingleDir {
for i := range cgoSrcs {
cgoSrcs[i] = filepath.Base(cgoSrcs[i])
for i := range opt.source.cgo {
opt.source.cgo[i] = filepath.Base(opt.source.cgo[i])
}
} else {
srcDir = filepath.Join(workDir, "cgosrcs")
if err := os.Mkdir(srcDir, 0777); err != nil {
return "", nil, nil, err
}
copiedSrcs, err := gatherSrcs(srcDir, cgoSrcs)
copiedSrcs, err := gatherSrcs(srcDir, opt.source.cgo)
if err != nil {
return "", nil, nil, err
}
cgoSrcs = copiedSrcs
opt.source.cgo = copiedSrcs
}

// Generate Go and C code.
hdrDirs := map[string]bool{}
var hdrIncludes []string
for _, hdr := range hSrcs {
for _, hdr := range opt.source.h {
hdrDir := filepath.Dir(hdr)
if !hdrDirs[hdrDir] {
hdrDirs[hdrDir] = true
Expand All @@ -140,28 +159,28 @@ func cgo2(goenv *env, goSrcs, cgoSrcs, cSrcs, cxxSrcs, objcSrcs, objcxxSrcs, sSr
}
// Trim the execroot from the //line comments emitted by cgo.
args := goenv.goTool("cgo", "-srcdir", srcDir, "-objdir", workDir, "-trimpath", execRoot)
if packagePath != "" {
args = append(args, "-importpath", packagePath)
if opt.packagePath != "" {
args = append(args, "-importpath", opt.packagePath)
}
args = append(args, "--")
args = append(args, cppFlags...)
args = append(args, opt.ccToolchain.cppFlags...)
args = append(args, hdrIncludes...)
args = append(args, cFlags...)
args = append(args, cgoSrcs...)
args = append(args, opt.ccToolchain.cFlags...)
args = append(args, opt.source.cgo...)
if err := goenv.runCommand(args); err != nil {
return "", nil, nil, err
}

if cgoExportHPath != "" {
if err := copyFile(filepath.Join(workDir, "_cgo_export.h"), cgoExportHPath); err != nil {
if opt.cgoExportHPath != "" {
if err := copyFile(filepath.Join(workDir, "_cgo_export.h"), opt.cgoExportHPath); err != nil {
return "", nil, nil, err
}
}
genGoSrcs := make([]string, 1+len(cgoSrcs))
genGoSrcs := make([]string, 1+len(opt.source.cgo))
genGoSrcs[0] = filepath.Join(workDir, "_cgo_gotypes.go")
genCSrcs := make([]string, 1+len(cgoSrcs))
genCSrcs := make([]string, 1+len(opt.source.cgo))
genCSrcs[0] = filepath.Join(workDir, "_cgo_export.c")
for i, src := range cgoSrcs {
for i, src := range opt.source.cgo {
stem := strings.TrimSuffix(filepath.Base(src), ".go")
genGoSrcs[i+1] = filepath.Join(workDir, stem+".cgo1.go")
genCSrcs[i+1] = filepath.Join(workDir, stem+".cgo2.c")
Expand All @@ -170,32 +189,32 @@ func cgo2(goenv *env, goSrcs, cgoSrcs, cSrcs, cxxSrcs, objcSrcs, objcxxSrcs, sSr

// Compile C, C++, Objective-C/C++, and assembly code.
defaultCFlags := defaultCFlags(workDir)
combinedCFlags := combineFlags(cppFlags, hdrIncludes, cFlags, defaultCFlags)
combinedCFlags := combineFlags(opt.ccToolchain.cppFlags, hdrIncludes, opt.ccToolchain.cFlags, defaultCFlags)
for _, lang := range []struct{ srcs, flags []string }{
{genCSrcs, combinedCFlags},
{cSrcs, combinedCFlags},
{cxxSrcs, combineFlags(cppFlags, hdrIncludes, cxxFlags, defaultCFlags)},
{objcSrcs, combineFlags(cppFlags, hdrIncludes, objcFlags, defaultCFlags)},
{objcxxSrcs, combineFlags(cppFlags, hdrIncludes, objcxxFlags, defaultCFlags)},
{sSrcs, nil},
{opt.source.c, combinedCFlags},
{opt.source.cxx, combineFlags(opt.ccToolchain.cppFlags, hdrIncludes, opt.ccToolchain.cxxFlags, defaultCFlags)},
{opt.source.objc, combineFlags(opt.ccToolchain.cppFlags, hdrIncludes, opt.ccToolchain.objcFlags, defaultCFlags)},
{opt.source.objcxx, combineFlags(opt.ccToolchain.cppFlags, hdrIncludes, opt.ccToolchain.objcxxFlags, defaultCFlags)},
{opt.source.s, nil},
} {
for _, src := range lang.srcs {
obj := filepath.Join(workDir, fmt.Sprintf("_x%d.o", len(cObjs)))
cObjs = append(cObjs, obj)
if err := cCompile(goenv, src, cc, lang.flags, obj); err != nil {
if err := cCompile(goenv, src, opt.ccToolchain.cc, lang.flags, obj); err != nil {
return "", nil, nil, err
}
}
}

mainObj := filepath.Join(workDir, "_cgo_main.o")
if err := cCompile(goenv, cgoMainC, cc, combinedCFlags, mainObj); err != nil {
if err := cCompile(goenv, cgoMainC, opt.ccToolchain.cc, combinedCFlags, mainObj); err != nil {
return "", nil, nil, err
}

// Link cgo binary and use the symbols to generate _cgo_import.go.
mainBin := filepath.Join(workDir, "_cgo_.o") // .o is a lie; it's an executable
args = append([]string{cc, "-o", mainBin, mainObj}, cObjs...)
args = append([]string{opt.ccToolchain.cc, "-o", mainBin, mainObj}, cObjs...)
args = append(args, combinedLdFlags...)
var originalErrBuf bytes.Buffer
if err := goenv.runCommandToFile(os.Stdout, &originalErrBuf, args); err != nil {
Expand All @@ -222,7 +241,7 @@ func cgo2(goenv *env, goSrcs, cgoSrcs, cSrcs, cxxSrcs, objcSrcs, objcxxSrcs, sSr
// the failure of the original command.
if err2 := goenv.runCommandToFile(
os.Stdout,
ioutil.Discard,
io.Discard,
append(args, allowUnresolvedSymbolsLdFlag),
); err2 != nil {
os.Stderr.Write(relativizePaths(originalErrBuf.Bytes()))
Expand All @@ -233,24 +252,24 @@ func cgo2(goenv *env, goSrcs, cgoSrcs, cSrcs, cxxSrcs, objcSrcs, objcxxSrcs, sSr
}

cgoImportsGo := filepath.Join(workDir, "_cgo_imports.go")
args = goenv.goTool("cgo", "-dynpackage", packageName, "-dynimport", mainBin, "-dynout", cgoImportsGo)
args = goenv.goTool("cgo", "-dynpackage", opt.packageName, "-dynimport", mainBin, "-dynout", cgoImportsGo)
if err := goenv.runCommand(args); err != nil {
return "", nil, nil, err
}
genGoSrcs = append(genGoSrcs, cgoImportsGo)

// Copy regular Go source files into the work directory so that we can
// use -trimpath=workDir.
goBases, err := gatherSrcs(workDir, goSrcs)
goBases, err := gatherSrcs(workDir, opt.source.goSrcs)
if err != nil {
return "", nil, nil, err
}

allGoSrcs = make([]string, len(goSrcs)+len(genGoSrcs))
for i := range goSrcs {
allGoSrcs = make([]string, len(opt.source.goSrcs)+len(genGoSrcs))
for i := range opt.source.goSrcs {
allGoSrcs[i] = filepath.Join(workDir, goBases[i])
}
copy(allGoSrcs[len(goSrcs):], genGoSrcs)
copy(allGoSrcs[len(opt.source.goSrcs):], genGoSrcs)
return workDir, allGoSrcs, cObjs, nil
}

Expand All @@ -259,7 +278,7 @@ func cgo2(goenv *env, goSrcs, cgoSrcs, cSrcs, cxxSrcs, objcSrcs, objcxxSrcs, sSr
// It does not run cgo. This is used for packages with "cgo = True" but
// without any .go files that import "C". The Go command forbids this,
// but we have historically allowed it.
func compileCSources(goenv *env, cSrcs, cxxSrcs, objcSrcs, objcxxSrcs, sSrcs, hSrcs []string, cc string, cppFlags, cFlags, cxxFlags, objcFlags, objcxxFlags []string) (cObjs []string, err error) {
func compileCSources(goenv *env, source *sourceFiles, ccToolchain *ccToolchain) (cObjs []string, err error) {
workDir, cleanup, err := goenv.workDir()
if err != nil {
return nil, err
Expand All @@ -268,7 +287,7 @@ func compileCSources(goenv *env, cSrcs, cxxSrcs, objcSrcs, objcxxSrcs, sSrcs, hS

hdrDirs := map[string]bool{}
var hdrIncludes []string
for _, hdr := range hSrcs {
for _, hdr := range source.h {
hdrDir := filepath.Dir(hdr)
if !hdrDirs[hdrDir] {
hdrDirs[hdrDir] = true
Expand All @@ -278,16 +297,16 @@ func compileCSources(goenv *env, cSrcs, cxxSrcs, objcSrcs, objcxxSrcs, sSrcs, hS

defaultCFlags := defaultCFlags(workDir)
for _, lang := range []struct{ srcs, flags []string }{
{cSrcs, combineFlags(cppFlags, hdrIncludes, cFlags, defaultCFlags)},
{cxxSrcs, combineFlags(cppFlags, hdrIncludes, cxxFlags, defaultCFlags)},
{objcSrcs, combineFlags(cppFlags, hdrIncludes, objcFlags, defaultCFlags)},
{objcxxSrcs, combineFlags(cppFlags, hdrIncludes, objcxxFlags, defaultCFlags)},
{sSrcs, nil},
{source.c, combineFlags(ccToolchain.cppFlags, hdrIncludes, ccToolchain.cFlags, defaultCFlags)},
{source.cxx, combineFlags(ccToolchain.cppFlags, hdrIncludes, ccToolchain.cxxFlags, defaultCFlags)},
{source.objc, combineFlags(ccToolchain.cppFlags, hdrIncludes, ccToolchain.objcFlags, defaultCFlags)},
{source.objcxx, combineFlags(ccToolchain.cppFlags, hdrIncludes, ccToolchain.objcxxFlags, defaultCFlags)},
{source.s, nil},
} {
for _, src := range lang.srcs {
obj := filepath.Join(workDir, fmt.Sprintf("_x%d.o", len(cObjs)))
cObjs = append(cObjs, obj)
if err := cCompile(goenv, src, cc, lang.flags, obj); err != nil {
if err := cCompile(goenv, src, ccToolchain.cc, lang.flags, obj); err != nil {
return nil, err
}
}
Expand Down
29 changes: 26 additions & 3 deletions go/tools/builders/compilepkg.go
View file
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Original file line number Diff line number Diff line change
Expand Up @@ -22,7 +22,6 @@ import (
"errors"
"flag"
"fmt"
"io/ioutil"
"os"
"os/exec"
"path"
Expand Down Expand Up @@ -339,15 +338,39 @@ func compileArchive(
// If the package uses Cgo, compile .s and .S files with cgo2, not the Go assembler.
// Otherwise: the .s/.S files will be compiled with the Go assembler later
var srcDir string
srcDir, goSrcs, objFiles, err = cgo2(goenv, goSrcs, cgoSrcs, cSrcs, cxxSrcs, objcSrcs, objcxxSrcs, sSrcs, hSrcs, packagePath, packageName, cc, cppFlags, cFlags, cxxFlags, objcFlags, objcxxFlags, ldFlags, cgoExportHPath)
cgoOpt := &cgoOption{
packageName: packageName,
packagePath: packagePath,
cgoExportHPath: cgoExportHPath,
source: &sourceFiles{
goSrcs: goSrcs,
cgo: cgoSrcs,
c: cSrcs,
cxx: cxxSrcs,
objc: objcSrcs,
objcxx: objcxxSrcs,
s: sSrcs,
h: hSrcs,
},
ccToolchain: &ccToolchain{
cc: cc,
cppFlags: cppFlags,
cFlags: cFlags,
cxxFlags: cxxFlags,
objcFlags: objcFlags,
objcxxFlags: objcxxFlags,
ldFlags: ldFlags,
},
}
srcDir, goSrcs, objFiles, err = cgo(goenv, cgoOpt)
if err != nil {
return err
}

gcFlags = append(gcFlags, createTrimPath(gcFlags, srcDir))
} else {
if cgoExportHPath != "" {
if err := ioutil.WriteFile(cgoExportHPath, nil, 0o666); err != nil {
if err := os.WriteFile(cgoExportHPath, nil, 0o666); err != nil {
return err
}
}
Expand Down