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mirror of https://github.com/golang/go synced 2024-11-21 14:54:40 -07:00

cgo: new cgo

Very few changes here: the subtle ones are in Make.pkg.

Note that incredibly (and importantly) there are
no changes necessary to the test programs in misc/cgo.

R=iant
CC=golang-dev
https://golang.org/cl/3504041
This commit is contained in:
Russ Cox 2010-12-08 13:56:51 -05:00
parent f5690004c2
commit 14d677ecba
4 changed files with 105 additions and 52 deletions

View File

@ -36,12 +36,9 @@ INSTALLFILES+=$(pkgdir)/$(TARG).a
# The rest of the cgo rules are below, but these variable updates
# must be done here so they apply to the main rules.
ifdef CGOFILES
CGOTARG=cgo_$(subst /,_,$(TARG))
GOFILES+=$(patsubst %.go,%.cgo1.go,$(CGOFILES))
GOFILES+=_cgo_gotypes.go
OFILES+=_cgo_defun.$O
GOFILES+=$(patsubst %.go,%.cgo1.go,$(CGOFILES)) _cgo_gotypes.go
GCC_OFILES=$(patsubst %.go,%.cgo2.o,$(CGOFILES))
INSTALLFILES+=$(pkgdir)/$(CGOTARG).so
OFILES+=_cgo_defun.$O _cgo_import.$O $(GCC_OFILES)
endif
PREREQ+=$(patsubst %,%.make,$(DEPS))
@ -50,7 +47,9 @@ coverage:
gotest
6cov -g $(shell pwd) $O.out | grep -v '_test\.go:'
CLEANFILES+=*.cgo1.go *.cgo2.c _cgo_defun.c _cgo_gotypes.go _cgo_export.* *.so _obj _test _testmain.go *.exe
CLEANFILES+=*.cgo1.go *.cgo2.c _cgo_defun.c _cgo_gotypes.go _cgo_export.*
CLEANFILES+=_cgo_.c _cgo_import.c _cgo_main.c
CLEANFILES+=*.so _obj _test _testmain.go *.exe
test:
gotest
@ -122,18 +121,34 @@ _cgo_gotypes.go _cgo_export.c _cgo_export.h: _cgo_defun.c
%.cgo1.go %.cgo2.c: _cgo_defun.c
@true
# Compile rules for gcc source files.
%.cgo2.o: %.cgo2.c
$(HOST_CC) $(_CGO_CFLAGS_$(GOARCH)) -fPIC -O2 -o $@ -c $(CGO_CFLAGS) $*.cgo2.c
$(HOST_CC) $(_CGO_CFLAGS_$(GOARCH)) -g -fPIC -O2 -o $@ -c $(CGO_CFLAGS) $*.cgo2.c
_cgo_export.o: _cgo_export.c _cgo_export.h
$(HOST_CC) $(_CGO_CFLAGS_$(GOARCH)) -fPIC -O2 -o $@ -c $(CGO_CFLAGS) _cgo_export.c
$(HOST_CC) $(_CGO_CFLAGS_$(GOARCH)) -g -fPIC -O2 -o $@ -c $(CGO_CFLAGS) _cgo_export.c
# To find out which symbols are needed from external libraries
# and which libraries are needed, we build a simple a.out that
# links all the objects we just created and then use cgo -dynimport
# to inspect it. That is, we make gcc tell us which dynamic symbols
# and libraries are involved, instead of duplicating gcc's logic ourselves.
_cgo_main.c:
echo 'int main() { return 0; }' >$@
_cgo_main.o: _cgo_main.c
$(HOST_CC) $(_CGO_CFLAGS_$(GOARCH)) -g -fPIC -O2 -o $@ -c $(CGO_CFLAGS) _cgo_main.c
_cgo1_.o: _cgo_main.o $(GCC_OFILES)
$(HOST_CC) $(_CGO_CFLAGS_$(GOARCH)) -g -fPIC -O2 -o $@ $^ $(CGO_LDFLAGS)
_cgo_import.c: _cgo1_.o
cgo -dynimport _cgo1_.o >_$@ && mv -f _$@ $@
# The rules above added x.cgo1.go and _cgo_gotypes.go to $(GOFILES),
# added _cgo_defun.$O to $OFILES, and added the installed copy of
# package_x.so (built from x.cgo2.c) to $(INSTALLFILES).
RUNTIME_CFLAGS=-I"$(GOROOT)/src/pkg/runtime"
# Have to run gcc with the right size argument on hybrid 32/64 machines.
_CGO_CFLAGS_386=-m32
_CGO_CFLAGS_amd64=-m64
@ -142,24 +157,13 @@ _CGO_LDFLAGS_linux=-shared -lpthread -lm
_CGO_LDFLAGS_darwin=-dynamiclib -Wl,-undefined,dynamic_lookup
_CGO_LDFLAGS_windows=-shared -lm -mthreads
# Compile x.cgo4.c with gcc to make package_x.so.
# Have to compile the runtime header.
RUNTIME_CFLAGS=-I"$(GOROOT)/src/pkg/runtime"
# Compile _cgo_defun.c with 6c; needs access to the runtime headers.
_cgo_defun.$O: _cgo_defun.c
$(CC) $(CFLAGS) $(RUNTIME_CFLAGS) _cgo_defun.c
$(CGOTARG).so: $(GCC_OFILES) $(CGO_DEPS)
$(HOST_CC) $(_CGO_CFLAGS_$(GOARCH)) -o $@ $(GCC_OFILES) $(CGO_LDFLAGS) $(_CGO_LDFLAGS_$(GOOS))
$(pkgdir)/$(CGOTARG).so: $(CGOTARG).so
@test -d $(QUOTED_GOROOT)/pkg && mkdir -p $(pkgdir)
rm -f "$@"
cp $(CGOTARG).so "$@"
ifneq ($(CGOFILES),)
testpackage: $(CGOTARG).so
endif
# Generic build rules.
# These come last so that the rules above can override them
# for more specific file names.

View File

@ -31,6 +31,8 @@ type Package struct {
Typedef map[string]ast.Expr // accumulated Typedef from Files
ExpFunc []*ExpFunc // accumulated ExpFunc from Files
Decl []ast.Decl
GoFiles []string // list of Go files
GccFiles []string // list of gcc output files
}
// A File collects information about a single Go input file.
@ -105,9 +107,31 @@ var ptrSizeMap = map[string]int64{
var fset = token.NewFileSet()
var dynobj = flag.String("dynimport", "", "if non-empty, print dynamic import data for that file")
func main() {
flag.Usage = usage
flag.Parse()
if *dynobj != "" {
// cgo -dynimport is essentially a separate helper command
// built into the cgo binary. It scans a gcc-produced executable
// and dumps information about the imported symbols and the
// imported libraries. The Make.pkg rules for cgo prepare an
// appropriate executable and then use its import information
// instead of needing to make the linkers duplicate all the
// specialized knowledge gcc has about where to look for imported
// symbols and which ones to use.
syms, imports := dynimport(*dynobj)
for _, sym := range syms {
fmt.Printf("#pragma dynimport %s %s %q\n", sym, sym, "")
}
for _, p := range imports {
fmt.Printf("#pragma dynimport %s %s %q\n", "_", "_", p)
}
return
}
args := flag.Args()
if len(args) < 1 {
usage()
@ -209,19 +233,6 @@ func (p *Package) Record(f *File) {
}
}
if len(f.ExpFunc) > 0 {
n := len(p.ExpFunc)
ef := make([]*ExpFunc, n+len(f.ExpFunc))
copy(ef, p.ExpFunc)
copy(ef[n:], f.ExpFunc)
p.ExpFunc = ef
}
if len(f.AST.Decls) > 0 {
n := len(p.Decl)
d := make([]ast.Decl, n+len(f.AST.Decls))
copy(d, p.Decl)
copy(d[n:], f.AST.Decls)
p.Decl = d
}
p.ExpFunc = append(p.ExpFunc, f.ExpFunc...)
p.Decl = append(p.Decl, f.AST.Decls...)
}

View File

@ -6,6 +6,8 @@ package main
import (
"bytes"
"debug/elf"
"debug/macho"
"fmt"
"go/ast"
"go/printer"
@ -36,6 +38,7 @@ func (p *Package) writeDefs() {
fmt.Fprintf(fgo2, "package %s\n\n", p.PackageName)
fmt.Fprintf(fgo2, "import \"unsafe\"\n\n")
fmt.Fprintf(fgo2, "import \"os\"\n\n")
fmt.Fprintf(fgo2, "import _ \"runtime/cgo\"\n\n")
fmt.Fprintf(fgo2, "type _ unsafe.Pointer\n\n")
fmt.Fprintf(fgo2, "func _Cerrno(dst *os.Error, x int) { *dst = os.Errno(x) }\n")
@ -46,13 +49,19 @@ func (p *Package) writeDefs() {
}
fmt.Fprintf(fgo2, "type _Ctype_void [0]byte\n")
fmt.Fprintf(fc, cProlog, soprefix, soprefix, soprefix, soprefix, soprefix)
fmt.Fprintf(fc, cProlog)
var cVars []string
for _, n := range p.Name {
if n.Kind != "var" {
continue
}
fmt.Fprintf(fc, "#pragma dynimport ·%s %s \"%s%s.so\"\n", n.Mangle, n.C, soprefix, sopath)
cVars = append(cVars, n.C)
fmt.Fprintf(fc, "extern byte *%s;\n", n.C)
fmt.Fprintf(fc, "void *·%s = &%s;\n", n.Mangle, n.C)
fmt.Fprintf(fc, "\n")
fmt.Fprintf(fgo2, "var %s ", n.Mangle)
printer.Fprint(fgo2, fset, &ast.StarExpr{X: n.Type.Go})
fmt.Fprintf(fgo2, "\n")
@ -78,6 +87,42 @@ func (p *Package) writeDefs() {
fc.Close()
}
func dynimport(obj string) (syms, imports []string) {
var f interface {
ImportedLibraries() ([]string, os.Error)
ImportedSymbols() ([]string, os.Error)
}
var isMacho bool
var err1, err2 os.Error
if f, err1 = elf.Open(obj); err1 != nil {
if f, err2 = macho.Open(obj); err2 != nil {
fatal("cannot parse %s as ELF (%v) or Mach-O (%v)", obj, err1, err2)
}
isMacho = true
}
var err os.Error
syms, err = f.ImportedSymbols()
if err != nil {
fatal("cannot load dynamic symbols: %v", err)
}
if isMacho {
// remove leading _ that OS X insists on
for i, s := range syms {
if len(s) >= 2 && s[0] == '_' {
syms[i] = s[1:]
}
}
}
imports, err = f.ImportedLibraries()
if err != nil {
fatal("cannot load dynamic imports: %v", err)
}
return
}
// Construct a gcc struct matching the 6c argument frame.
// Assumes that in gcc, char is 1 byte, short 2 bytes, int 4 bytes, long long 8 bytes.
// These assumptions are checked by the gccProlog.
@ -167,9 +212,7 @@ func (p *Package) writeDefsFunc(fc, fgo2 *os.File, n *Name, soprefix, sopath str
_, argSize = p.structType(n)
// C wrapper calls into gcc, passing a pointer to the argument frame.
// Also emit #pragma to get a pointer to the gcc wrapper.
fmt.Fprintf(fc, "#pragma dynimport _cgo%s _cgo%s \"%s%s.so\"\n", n.Mangle, n.Mangle, soprefix, sopath)
fmt.Fprintf(fc, "void (*_cgo%s)(void*);\n", n.Mangle)
fmt.Fprintf(fc, "void _cgo%s(void*);\n", n.Mangle)
fmt.Fprintf(fc, "\n")
fmt.Fprintf(fc, "void\n")
fmt.Fprintf(fc, "·%s(struct{uint8 x[%d];}p)\n", n.Mangle, argSize)
@ -212,6 +255,9 @@ func (p *Package) writeOutput(f *File, srcfile string) {
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")
// Write Go output: Go input with rewrites of C.xxx to _C_xxx.
fmt.Fprintf(fgo1, "// Created by cgo - DO NOT EDIT\n")
fmt.Fprintf(fgo1, "//line %s:1\n", srcfile)
@ -592,12 +638,6 @@ const cProlog = `
#include "runtime.h"
#include "cgocall.h"
#pragma dynimport initcgo initcgo "%slibcgo.so"
#pragma dynimport libcgo_thread_start libcgo_thread_start "%slibcgo.so"
#pragma dynimport libcgo_set_scheduler libcgo_set_scheduler "%slibcgo.so"
#pragma dynimport _cgo_malloc _cgo_malloc "%slibcgo.so"
#pragma dynimport _cgo_free _cgo_free "%slibcgo.so"
void ·_Cerrno(void*, int32);
void

View File

@ -45,9 +45,8 @@ func run(stdin []byte, argv []string) (stdout, stderr []byte, ok bool) {
w0.Close()
c <- true
}()
var xstdout []byte // TODO(rsc): delete after 6g can take address of out parameter
go func() {
xstdout, _ = ioutil.ReadAll(r1)
stdout, _ = ioutil.ReadAll(r1)
r1.Close()
c <- true
}()
@ -55,7 +54,6 @@ func run(stdin []byte, argv []string) (stdout, stderr []byte, ok bool) {
r2.Close()
<-c
<-c
stdout = xstdout
w, err := os.Wait(pid, 0)
if err != nil {