cmd/cgo: remove obsolete -cdefs flag

Now that there's no 6c compiler anymore, there's no need for cgo to
generate C headers that are compatible with it.

Fixes #9528

Change-Id: I43f53869719eb9a6065f1b39f66f060e604cbee0
Reviewed-on: https://go-review.googlesource.com/2482Reviewed-by: Ian Lance Taylor <iant@golang.org>

misc/cgo/testcdefs/cdefstest.c

-// Copyright 2013 The Go Authors.  All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-#include "runtime.h"
-#include "cdefstest.h"
-
-struct CdefsTest test;
-struct PackedTest packed;

misc/cgo/testcdefs/cdefstest.go

-// Copyright 2013 The Go Authors.  All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-//
-// +build ignore
-
-package cgotest
-
-/*
-// This file tests a bug found in the cgo -cdefs tool that incorrectly
-// translated Go pointer arrays generated by the cgo godefs tool back into C
-// pointer arrays.
-//
-// The comments below show how the type is translated from gcc-style C into Go
-// and back into C for both the buggy version and the correct version
-
-struct cdefsTest {
-	// This was already being handled correctly
-	// Correct: -> Array [20]int8 -> int8 array[20]
-	char array1[20];
-
-	// Buggy:   -> Array [20][20]int8 -> [20]int8 array[20]
-	// Correct: -> Array [20][20]int8 -> int8 array[20][20]
-	char array2[20][20];
-
-	// Buggy:   -> Array [20]*int8 -> *int8 array[20]
-	// Correct: -> Array [20]*int8 -> int8 *array[20]
-	char *array3[20];
-
-	// Buggy:   -> Array [20][20]*int8 -> [20]*int8 array[20]
-	// Correct: -> Array [20]**int8 -> int8 *array[20][20]
-	char *array4[20][20];
-
-	// Buggy:   -> Array [20][20]**int8 -> [20]**int8 array[20]
-	// Correct: -> Array [20][20]**int8 -> int8 **array[20][20]
-	char **array5[20][20];
-};
-
-// Test that packed structures can be translated to C correctly too.
-// See issue 8477.
-
-struct packedTest {
-	char first;
-	int second;
-	long long third;
-} __attribute__((packed));
-
-// Test that conflicting type definitions don't cause problems with cgo.
-// See issue 8477.
-
-typedef struct timespec {
-	double bogus;
-} pid_t;
-
-*/
-import "C"
-
-type CdefsTest C.struct_cdefsTest
-
-//type PackedTest C.struct_packedTest

misc/cgo/testcdefs/main.c

-// Copyright 2013 The Go Authors.  All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-#include "runtime.h"
-#include "cdefstest.h"
-
-void runtime·printf(int8*, ...);
-
-// From cdefstest.go.
-typedef struct CdefsOrig CdefsOrig;
-struct CdefsOrig {
-	int8 array1[20];
-	int8 array2[20][20];
-	int8 *array3[20];
-	int8 *array4[20][20];
-	int8 **array5[20][20];
-};
-
-// Packed structs are no longer supported for -cdefs.
-/*
-typedef struct PackedOrig PackedOrig;
-#pragma pack on
-struct PackedOrig {
-	int8 first;
-	int32 second;
-	int64 third;
-};
-#pragma pack off
-*/
-
-void
-main·test(int32 ret)
-{
-	CdefsOrig o;
-	CdefsTest t;
-	// PackedOrig po;
-	// PackedTest pt;
-	
-	ret = 0;
-	if(sizeof(t.array1) != sizeof(o.array1) || offsetof(CdefsTest, array1[0]) != offsetof(CdefsOrig, array1[0])) {
-		runtime·printf("array1: size, offset = %d, %d, want %d, %d\n", sizeof(t.array1), offsetof(CdefsTest, array1[0]), sizeof(o.array1), offsetof(CdefsOrig, array1[0]));
-		ret = 1;
-	}
-	if(sizeof(t.array2) != sizeof(o.array2) || offsetof(CdefsTest, array2[0][0]) != offsetof(CdefsOrig, array2[0][0])) {
-		runtime·printf("array2: size, offset = %d, %d, want %d, %d\n", sizeof(t.array2), offsetof(CdefsTest, array2[0][0]), sizeof(o.array2), offsetof(CdefsOrig, array2[0][0]));
-		ret = 1;
-	}
-	if(sizeof(t.array3) != sizeof(o.array3) || offsetof(CdefsTest, array3[0]) != offsetof(CdefsOrig, array3[0])) {
-		runtime·printf("array3: size, offset = %d, %d, want %d, %d\n", sizeof(t.array3), offsetof(CdefsTest, array3[0]), sizeof(o.array3), offsetof(CdefsOrig, array3[0]));
-		ret = 1;
-	}
-	if(sizeof(t.array4) != sizeof(o.array4) || offsetof(CdefsTest, array4[0][0]) != offsetof(CdefsOrig, array4[0][0])) {
-		runtime·printf("array4: size, offset = %d, %d, want %d, %d\n", sizeof(t.array4), offsetof(CdefsTest, array4[0][0]), sizeof(o.array4), offsetof(CdefsOrig, array4[0][0]));
-		ret = 1;
-	}
-	if(sizeof(t.array5) != sizeof(o.array5) || offsetof(CdefsTest, array5[0][0]) != offsetof(CdefsOrig, array5[0][0])) {
-		runtime·printf("array5: size, offset = %d, %d, want %d, %d\n", sizeof(t.array5), offsetof(CdefsTest, array5[0][0]), sizeof(o.array5), offsetof(CdefsOrig, array5[0][0]));
-		ret = 1;
-	}
-/*
-	if(sizeof(pt.first) != sizeof(po.first) || offsetof(PackedTest, first) != offsetof(PackedOrig, first)) {
-		runtime·printf("first: size, offset = %d, %d, want %d, %d\n", sizeof(pt.first), offsetof(PackedTest, first), sizeof(po.first), offsetof(PackedOrig, first));
-		ret = 1;
-	}
-	if(sizeof(pt.second) != sizeof(po.second) || offsetof(PackedTest, second) != offsetof(PackedOrig, second)) {
-		runtime·printf("second: size, offset = %d, %d, want %d, %d\n", sizeof(pt.second), offsetof(PackedTest, second), sizeof(po.second), offsetof(PackedOrig, second));
-		ret = 1;
-	}
-	if(sizeof(pt.third) != sizeof(po.third) || offsetof(PackedTest, third) != offsetof(PackedOrig, third)) {
-		runtime·printf("third: size, offset = %d, %d, want %d, %d\n", sizeof(pt.third), offsetof(PackedTest, third), sizeof(po.third), offsetof(PackedOrig, third));
-		ret = 1;
-	}
-*/
-	FLUSH(&ret); // flush return value
-}

misc/cgo/testcdefs/main.go

-// Copyright 2013 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package main
-
-import "os"
-
-func test() int32 // in main.c
-
-func main() {
-	os.Exit(int(test()))
-}

misc/cgo/testcdefs/test.bash

-# Copyright 2013 The Go Authors. All rights reserved.
-# Use of this source code is governed by a BSD-style
-# license that can be found in the LICENSE file.
-
-# Just add issue file prefixes to this list if more issues come up
-FILE_PREFIXES="cdefstest"
-
-for FP in $FILE_PREFIXES
-do 
-  go tool cgo -cdefs ${FP}.go > ${FP}.h
-done
-
-go build . && ./testcdefs
-EXIT=$?
-rm -rf _obj testcdefs *.h
-exit $EXIT

src/cmd/cgo/doc.go

@@ -237,10 +237,6 @@ The following options are available when running cgo directly:
 		Write out input file in Go syntax replacing C package
 		names with real values. Used to generate files in the
 		syscall package when bootstrapping a new target.
-	-cdefs
-		Like -godefs, but write file in C syntax.
-		Used to generate files in the runtime package when
-		bootstrapping a new target.
 	-objdir directory
 		Put all generated files in directory.
 	-gccgo

src/cmd/cgo/gcc.go

@@ -582,7 +582,7 @@ func (p *Package) mangleName(n *Name) {
 
 // rewriteRef rewrites all the C.xxx references in f.AST to refer to the
 // Go equivalents, now that we have figured out the meaning of all
-// the xxx.  In *godefs or *cdefs mode, rewriteRef replaces the names
+// the xxx.  In *godefs mode, rewriteRef replaces the names
 // with full definitions instead of mangled names.
 func (p *Package) rewriteRef(f *File) {
 	// Keep a list of all the functions, to remove the ones
@@ -688,7 +688,7 @@ func (p *Package) rewriteRef(f *File) {
 				error_(r.Pos(), "must call C.%s", fixGo(r.Name.Go))
 			}
 		}
-		if *godefs || *cdefs {
+		if *godefs {
 			// Substitute definition for mangled type name.
 			if id, ok := expr.(*ast.Ident); ok {
 				if t := typedef[id.Name]; t != nil {
@@ -992,8 +992,8 @@ func (c *typeConv) Init(ptrSize, intSize int64) {
 	c.goVoid = c.Ident("_Ctype_void")
 
 	// Normally cgo translates void* to unsafe.Pointer,
-	// but for historical reasons -cdefs and -godefs use *byte instead.
-	if *cdefs || *godefs {
+	// but for historical reasons -godefs uses *byte instead.
+	if *godefs {
 		c.goVoidPtr = &ast.StarExpr{X: c.byte}
 	} else {
 		c.goVoidPtr = c.Ident("unsafe.Pointer")
@@ -1334,8 +1334,8 @@ func (c *typeConv) Type(dtype dwarf.Type, pos token.Pos) *Type {
 		// If sub.Go.Name is "_Ctype_struct_foo" or "_Ctype_union_foo" or "_Ctype_class_foo",
 		// use that as the Go form for this typedef too, so that the typedef will be interchangeable
 		// with the base type.
-		// In -godefs and -cdefs mode, do this for all typedefs.
-		if isStructUnionClass(sub.Go) || *godefs || *cdefs {
+		// In -godefs mode, do this for all typedefs.
+		if isStructUnionClass(sub.Go) || *godefs {
 			t.Go = sub.Go
 
 			if isStructUnionClass(sub.Go) {
@@ -1397,7 +1397,7 @@ func (c *typeConv) Type(dtype dwarf.Type, pos token.Pos) *Type {
 			name := c.Ident("_Ctype_" + s)
 			tt := *t
 			typedef[name.Name] = &tt
-			if !*godefs && !*cdefs {
+			if !*godefs {
 				t.Go = name
 			}
 		}
@@ -1573,7 +1573,7 @@ func (c *typeConv) Struct(dt *dwarf.StructType, pos token.Pos) (expr *ast.Struct
 		used[f.Name] = true
 	}
 
-	if !*godefs && !*cdefs {
+	if !*godefs {
 		for cid, goid := range ident {
 			if token.Lookup(goid).IsKeyword() {
 				// Avoid keyword
@@ -1600,12 +1600,12 @@ func (c *typeConv) Struct(dt *dwarf.StructType, pos token.Pos) (expr *ast.Struct
 		name := f.Name
 		ft := f.Type
 
-		// In godefs or cdefs mode, if this field is a C11
+		// In godefs mode, if this field is a C11
 		// anonymous union then treat the first field in the
 		// union as the field in the struct.  This handles
 		// cases like the glibc <sys/resource.h> file; see
 		// issue 6677.
-		if *godefs || *cdefs {
+		if *godefs {
 			if st, ok := f.Type.(*dwarf.StructType); ok && name == "" && st.Kind == "union" && len(st.Field) > 0 && !used[st.Field[0].Name] {
 				name = st.Field[0].Name
 				ident[name] = name
@@ -1635,14 +1635,12 @@ func (c *typeConv) Struct(dt *dwarf.StructType, pos token.Pos) (expr *ast.Struct
 			talign = size
 		}
 
-		if talign > 0 && f.ByteOffset%talign != 0 && !*cdefs {
+		if talign > 0 && f.ByteOffset%talign != 0 {
 			// Drop misaligned fields, the same way we drop integer bit fields.
 			// The goal is to make available what can be made available.
 			// Otherwise one bad and unneeded field in an otherwise okay struct
 			// makes the whole program not compile. Much of the time these
 			// structs are in system headers that cannot be corrected.
-			// Exception: In -cdefs mode, we use #pragma pack, so misaligned
-			// fields should still work.
 			continue
 		}
 		n := len(fld)
@@ -1672,7 +1670,7 @@ func (c *typeConv) Struct(dt *dwarf.StructType, pos token.Pos) (expr *ast.Struct
 	buf.WriteString("}")
 	csyntax = buf.String()
 
-	if *godefs || *cdefs {
+	if *godefs {
 		godefsFields(fld)
 	}
 	expr = &ast.StructType{Fields: &ast.FieldList{List: fld}}
@@ -1707,9 +1705,7 @@ func godefsFields(fld []*ast.Field) {
 				n.Name = "Pad_cgo_" + strconv.Itoa(npad)
 				npad++
 			}
-			if !*cdefs {
-				n.Name = upper(n.Name)
-			}
+			n.Name = upper(n.Name)
 		}
 	}
 }
@@ -1721,9 +1717,6 @@ func godefsFields(fld []*ast.Field) {
 // package syscall's data structures, we drop a common prefix
 // (so sec, usec, which will get turned into Sec, Usec for exporting).
 func fieldPrefix(fld []*ast.Field) string {
-	if *cdefs {
-		return ""
-	}
 	prefix := ""
 	for _, f := range fld {
 		for _, n := range f.Names {

src/cmd/cgo/godefs.go

@@ -114,173 +114,6 @@ func (p *Package) godefs(f *File, srcfile string) string {
 	return buf.String()
 }
 
-// cdefs returns the output for -cdefs mode.
-// The easiest way to do this is to translate the godefs Go to C.
-func (p *Package) cdefs(f *File, srcfile string) string {
-	godefsOutput := p.godefs(f, srcfile)
-
-	lines := strings.Split(godefsOutput, "\n")
-	lines[0] = "// Created by cgo -cdefs - DO NOT EDIT"
-
-	for i, line := range lines {
-		lines[i] = strings.TrimSpace(line)
-	}
-
-	var out bytes.Buffer
-	printf := func(format string, args ...interface{}) { fmt.Fprintf(&out, format, args...) }
-
-	didTypedef := false
-	for i := 0; i < len(lines); i++ {
-		line := lines[i]
-
-		// Delete
-		//	package x
-		if strings.HasPrefix(line, "package ") {
-			continue
-		}
-
-		// Convert
-		//	const (
-		//		A = 1
-		//		B = 2
-		//	)
-		//
-		// to
-		//
-		//	enum {
-		//		A = 1,
-		//		B = 2,
-		//	};
-		if line == "const (" {
-			printf("enum {\n")
-			for i++; i < len(lines) && lines[i] != ")"; i++ {
-				line = lines[i]
-				if line != "" {
-					printf("\t%s,", line)
-				}
-				printf("\n")
-			}
-			printf("};\n")
-			continue
-		}
-
-		// Convert
-		//	const A = 1
-		// to
-		//	enum { A = 1 };
-		if strings.HasPrefix(line, "const ") {
-			printf("enum { %s };\n", line[len("const "):])
-			continue
-		}
-
-		// On first type definition, typedef all the structs
-		// in case there are dependencies between them.
-		if !didTypedef && strings.HasPrefix(line, "type ") {
-			didTypedef = true
-			for _, line := range lines {
-				line = strings.TrimSpace(line)
-				if strings.HasPrefix(line, "type ") && strings.HasSuffix(line, " struct {") {
-					s := strings.TrimSuffix(strings.TrimPrefix(line, "type "), " struct {")
-					printf("typedef struct %s %s;\n", s, s)
-				}
-			}
-			printf("\n")
-			printf("#pragma pack on\n")
-			printf("\n")
-		}
-
-		// Convert
-		//	type T struct {
-		//		X int64
-		//		Y *int32
-		//		Z [4]byte
-		//	}
-		//
-		// to
-		//
-		//	struct T {
-		//		int64 X;
-		//		int32 *Y;
-		//		byte Z[4];
-		//	}
-		if strings.HasPrefix(line, "type ") && strings.HasSuffix(line, " struct {") {
-			if len(lines) > i+1 && lines[i+1] == "}" {
-				// do not output empty struct
-				i++
-				continue
-			}
-			s := line[len("type ") : len(line)-len(" struct {")]
-			printf("struct %s {\n", s)
-			for i++; i < len(lines) && lines[i] != "}"; i++ {
-				line := lines[i]
-				if line != "" {
-					f := strings.Fields(line)
-					if len(f) != 2 {
-						fmt.Fprintf(os.Stderr, "cgo: cannot parse struct field: %s\n", line)
-						nerrors++
-						continue
-					}
-					printf("\t%s;", cdecl(f[0], f[1]))
-				}
-				printf("\n")
-			}
-			printf("};\n")
-			continue
-		}
-
-		// Convert
-		//	type T int
-		// to
-		//	typedef int T;
-		if strings.HasPrefix(line, "type ") {
-			f := strings.Fields(line[len("type "):])
-			if len(f) != 2 {
-				fmt.Fprintf(os.Stderr, "cgo: cannot parse type definition: %s\n", line)
-				nerrors++
-				continue
-			}
-			printf("typedef\t%s;\n", cdecl(f[0], f[1]))
-			continue
-		}
-
-		printf("%s\n", line)
-	}
-
-	if didTypedef {
-		printf("\n")
-		printf("#pragma pack off\n")
-	}
-
-	return out.String()
-}
-
-// cdecl returns the C declaration for the given Go name and type.
-// It only handles the specific cases necessary for converting godefs output.
-func cdecl(name, typ string) string {
-	// X *[0]byte -> X *void
-	if strings.HasPrefix(typ, "*[0]") {
-		typ = "*void"
-	}
-	// X [4]byte -> X[4] byte
-	for strings.HasPrefix(typ, "[") {
-		i := strings.Index(typ, "]") + 1
-		name = name + typ[:i]
-		typ = typ[i:]
-	}
-	// X *byte -> *X byte
-	for strings.HasPrefix(typ, "*") {
-		name = "*" + name
-		typ = typ[1:]
-	}
-	// X T -> T X
-	// Handle the special case: 'unsafe.Pointer' is 'void *'
-	if typ == "unsafe.Pointer" {
-		typ = "void"
-		name = "*" + name
-	}
-	return typ + "\t" + name
-}
-
 var gofmtBuf bytes.Buffer
 
 // gofmt returns the gofmt-formatted string for an AST node.

src/cmd/cgo/main.go

@@ -155,10 +155,9 @@ var dynpackage = flag.String("dynpackage", "main", "set Go package for -dynimpor
 var dynlinker = flag.Bool("dynlinker", false, "record dynamic linker information in -dynimport mode")
 
 // These flags are for bootstrapping a new Go implementation,
-// to generate Go and C headers that match the data layout and
+// to generate Go types that match the data layout and
 // constant values used in the host's C libraries and system calls.
 var godefs = flag.Bool("godefs", false, "for bootstrap: write Go definitions for C file to standard output")
-var cdefs = flag.Bool("cdefs", false, "for bootstrap: write C definitions for C file to standard output")
 var objDir = flag.String("objdir", "", "object directory")
 
 var gccgo = flag.Bool("gccgo", false, "generate files for use with gccgo")
@@ -185,12 +184,7 @@ func main() {
 		return
 	}
 
-	if *godefs && *cdefs {
-		fmt.Fprintf(os.Stderr, "cgo: cannot use -cdefs and -godefs together\n")
-		os.Exit(2)
-	}
-
-	if *godefs || *cdefs {
+	if *godefs {
 		// Generating definitions pulled from header files,
 		// to be checked into Go repositories.
 		// Line numbers are just noise.
@@ -282,14 +276,12 @@ func main() {
 		p.Record(f)
 		if *godefs {
 			os.Stdout.WriteString(p.godefs(f, input))
-		} else if *cdefs {
-			os.Stdout.WriteString(p.cdefs(f, input))
 		} else {
 			p.writeOutput(f, input)
 		}
 	}
 
-	if !*godefs && !*cdefs {
+	if !*godefs {
 		p.writeDefs()
 	}
 	if nerrors > 0 {

src/run.bash

@@ -181,17 +181,6 @@ linux-linux-amd64-1 | freebsd-freebsd-amd64-1 | darwin-darwin-amd64-1)
 	fi
 esac
 
-# This tests cgo -cdefs. That mode is not supported,
-# so it's okay if it doesn't work on some systems.
-# In particular, it works badly with clang on OS X.
-# It doesn't work at all now that we disallow C code
-# outside runtime. Once runtime has no C code it won't
-# even be necessary.
-# [ "$CGO_ENABLED" != 1 ] || [ "$GOOS" == darwin ] ||
-# (xcd ../misc/cgo/testcdefs
-# ./test.bash || exit 1
-# ) || exit $?
-
 [ "$CGO_ENABLED" != 1 ] || [ "$GOOS" == darwin ] ||
 (xcd ../misc/cgo/testgodefs
 ./test.bash || exit 1