cgo working on linux/386

R=r
DELTA=70  (47 added, 4 deleted, 19 changed)
OCL=35167
CL=35171

misc/cgo/gmp/Makefile

@@ -10,6 +10,12 @@ CGOFILES=\
 
 CGO_LDFLAGS=-lgmp
 
+# To add flags necessary for locating the library or its include files,
+# set CGO_CFLAGS or CGO_LDFLAGS.  For example, to use an
+# alternate installation of the library:
+#	CGO_CFLAGS=-I/home/rsc/gmp32/include
+#	CGO_LDFLAGS+=-L/home/rsc/gmp32/lib
+
 # Can have plain GOFILES too, but this example doesn't.
 
 include $(GOROOT)/src/Make.pkg

src/Make.pkg

@@ -93,18 +93,21 @@ RUNTIME_CFLAGS=-I$(GOROOT)/src/pkg/runtime $(RUNTIME_CFLAGS_$(GOARCH))
 %.cgo3.$O: %.cgo3.c
 	$(CC) $(CFLAGS) $(RUNTIME_CFLAGS) $*.cgo3.c
 
+# Have to run gcc with the right size argument on hybrid 32/64 machines.
+_CGO_CFLAGS_386=-m32
+_CGO_CFLAGS_amd64=-m64
+
 # Compile x.cgo4.c with gcc to make package_x.so.
 %.cgo4.o: %.cgo4.c
-	gcc -fPIC -O2 -o $@ -c $(CGO_CFLAGS) $*.cgo4.c
+	gcc $(_CGO_CFLAGS_$(GOARCH)) -fPIC -O2 -o $@ -c $(CGO_CFLAGS) $*.cgo4.c
 
 $(elem)_%.so: %.cgo4.o
-	gcc -shared -o $@ $*.cgo4.o $(CGO_LDFLAGS)
+	gcc $(_CGO_CFLAGS_$(GOARCH)) -shared -o $@ $*.cgo4.o $(CGO_LDFLAGS)
 
 $(pkgdir)/$(dir)/$(elem)_%.so: $(elem)_%.so
 	@test -d $(GOROOT)/pkg && mkdir -p $(pkgdir)/$(dir)
 	cp $(elem)_$*.so $@
 
-
 # Generic build rules.
 # These come last so that the rules above can override them
 # for more specific file names.

src/cmd/8c/swt.c

@@ -231,6 +231,17 @@ outcode(void)
 	Binit(&b, f, OWRITE);
 
 	Bprint(&b, "%s\n", thestring);
+	if(ndynld > 0) {
+		int i;
+
+		Bprint(&b, "\n");
+		Bprint(&b, "$$  // exports\n\n");
+		Bprint(&b, "$$  // local types\n\n");
+		Bprint(&b, "$$  // dynld\n", thestring);
+		for(i=0; i<ndynld; i++)
+			Bprint(&b, "dynld %s %s %s\n", dynld[i].local, dynld[i].remote, dynld[i].path);
+		Bprint(&b, "$$\n\n");
+	}
 	Bprint(&b, "!\n");
 
 	outhist(&b);

src/cmd/8l/asm.c

@@ -333,7 +333,7 @@ doelf(void)
 		s = lookup(".dynsym", 0);
 		s->type = SDATA;
 		s->reachable = 1;
-		s->value += ELF64SYMSIZE;
+		s->value += ELF32SYMSIZE;
 
 		/* dynamic string table */
 		s = lookup(".dynstr", 0);
@@ -368,21 +368,20 @@ doelf(void)
 				if(!s->reachable || (s->type != SDATA && s->type != SBSS) || s->dynldname == nil)
 					continue;
 
-				d = lookup(".rela", 0);
+				d = lookup(".rel", 0);
 				addaddr(d, s);
-				adduint64(d, ELF64_R_INFO(nsym, R_X86_64_64));
-				adduint64(d, 0);
+				adduint32(d, ELF32_R_INFO(nsym, R_386_32));
 				nsym++;
 
 				d = lookup(".dynsym", 0);
 				adduint32(d, addstring(lookup(".dynstr", 0), s->dynldname));
+				adduint32(d, 0);	/* value */
+				adduint32(d, 0);	/* size of object */
 				t = STB_GLOBAL << 4;
 				t |= STT_OBJECT;	// works for func too, empirically
 				adduint8(d, t);
 				adduint8(d, 0);	/* reserved */
 				adduint16(d, SHN_UNDEF);	/* section where symbol is defined */
-				adduint64(d, 0);	/* value */
-				adduint64(d, 0);	/* size of object */
 
 				if(needlib(s->dynldlib))
 					elfwritedynent(dynamic, DT_NEEDED, addstring(dynstr, s->dynldlib));

src/cmd/cgo/ast.go

@@ -35,6 +35,7 @@ type Prog struct {
 	Typedef map[string]ast.Expr;
 	Vardef map[string]*Type;
 	Funcdef map[string]*FuncType;
+	PtrSize int64;
 }
 
 // A Type collects information about a type in both the C and Go worlds.

src/cmd/cgo/gcc.go

@@ -20,7 +20,7 @@ import (
 	"strings";
 )
 
-func (p *Prog) loadDebugInfo(ptrSize int64) {
+func (p *Prog) loadDebugInfo() {
 	// Construct a slice of unique names from p.Crefs.
 	m := make(map[string]int);
 	for _, c := range p.Crefs {
@@ -57,7 +57,7 @@ func (p *Prog) loadDebugInfo(ptrSize int64) {
 	b.WriteString("}\n");
 
 	kind := make(map[string]string);
-	_, stderr := gccDebug(b.Bytes());
+	_, stderr := p.gccDebug(b.Bytes());
 	if stderr == "" {
 		fatal("gcc produced no output");
 	}
@@ -109,7 +109,7 @@ func (p *Prog) loadDebugInfo(ptrSize int64) {
 	for i, n := range names {
 		fmt.Fprintf(&b, "typeof(%s) *__cgo__%d;\n", n, i);
 	}
-	d, stderr := gccDebug(b.Bytes());
+	d, stderr := p.gccDebug(b.Bytes());
 	if d == nil {
 		fatal("gcc failed:\n%s\non input:\n%s", stderr, b.Bytes());
 	}
@@ -158,7 +158,7 @@ func (p *Prog) loadDebugInfo(ptrSize int64) {
 
 	// Record types and typedef information in Crefs.
 	var conv typeConv;
-	conv.Init(ptrSize);
+	conv.Init(p.PtrSize);
 	for _, c := range p.Crefs {
 		i := m[c.Name];
 		c.TypeName = kind[c.Name] == "type";
@@ -175,9 +175,9 @@ func (p *Prog) loadDebugInfo(ptrSize int64) {
 // gccDebug runs gcc -gdwarf-2 over the C program stdin and
 // returns the corresponding DWARF data and any messages
 // printed to standard error.
-func gccDebug(stdin []byte) (*dwarf.Data, string) {
+func (p *Prog) gccDebug(stdin []byte) (*dwarf.Data, string) {
 	machine := "-m32";
-	if os.Getenv("GOARCH") == "amd64" {
+	if p.PtrSize == 8 {
 		machine = "-m64";
 	}
 

src/cmd/cgo/main.go

@@ -22,20 +22,34 @@ func usage() {
 	flag.PrintDefaults();
 }
 
-const ptrSize = 8	// TODO
+var ptrSizeMap = map[string]int64 {
+	"386": 4,
+	"amd64": 8,
+	"arm": 4
+}
 
 func main() {
 	flag.Usage = usage;
 	flag.Parse();
 
+	arch := os.Getenv("GOARCH");
+	if arch == "" {
+		fatal("$GOARCH is not set");
+	}
+	ptrSize, ok := ptrSizeMap[arch];
+	if !ok {
+		fatal("unknown architecture %s", arch);
+	}
+
 	args := flag.Args();
 	if len(args) != 1 {
 		usage();
 		os.Exit(2);
 	}
 	p := openProg(args[0]);
+	p.PtrSize = ptrSize;
 	p.Preamble = p.Preamble + "\n" + builtinProlog;
-	p.loadDebugInfo(ptrSize);
+	p.loadDebugInfo();
 	p.Vardef = make(map[string]*Type);
 	p.Funcdef = make(map[string]*FuncType);
 

src/cmd/cgo/out.go

@@ -100,8 +100,8 @@ func (p *Prog) writeOutput(srcfile string) {
 			structType += fmt.Sprintf("\t\t%s p%d;\n", t.C, i);
 			off += t.Size;
 		}
-		if off%ptrSize != 0 {
-			pad := ptrSize - off%ptrSize;
+		if off%p.PtrSize != 0 {
+			pad := p.PtrSize - off%p.PtrSize;
 			structType += fmt.Sprintf("\t\tchar __pad%d[%d];\n", npad, pad);
 			off += pad;
 			npad++;
@@ -116,8 +116,8 @@ func (p *Prog) writeOutput(srcfile string) {
 			structType += fmt.Sprintf("\t\t%s r;\n", t.C);
 			off += t.Size;
 		}
-		if off%ptrSize != 0 {
-			pad := ptrSize - off%ptrSize;
+		if off%p.PtrSize != 0 {
+			pad := p.PtrSize - off%p.PtrSize;
 			structType += fmt.Sprintf("\t\tchar __pad%d[%d];\n", npad, pad);
 			off += pad;
 			npad++;

src/libcgo/Makefile

@@ -4,15 +4,17 @@
 
 # not linked into build for now
 
+CFLAGS_386=-m32
+
 TARG=libcgo.so
 
 all: libcgo.so
 
 cgocall.o: cgocall.c
-	gcc -O2 -fPIC -o cgocall.o -c cgocall.c
+	gcc $(CFLAGS_$(GOARCH)) -O2 -fPIC -o cgocall.o -c cgocall.c
 
 libcgo.so: cgocall.o
-	gcc -shared -o libcgo.so cgocall.o -lpthread -lm
+	gcc $(CFLAGS_$(GOARCH)) -shared -o libcgo.so cgocall.o -lpthread -lm
 
 install: $(GOROOT)/pkg/$(GOOS)_$(GOARCH)/libcgo.so
 

src/pkg/runtime/linux/386/rt0.s

@@ -5,4 +5,11 @@
 // Darwin and Linux use the same linkage to main
 
 TEXT	_rt0_386_linux(SB),7,$0
+	MOVL	initcgo(SB), AX
+	TESTL	AX, AX
+	JZ	2(PC)
+	CALL	AX
+
 	JMP	_rt0_386(SB)
+
+GLOBL initcgo(SB), $4