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cgo: can look up C identifier kind (type or value) and type
gmp.go:197:4: type mpz_t C type mpz_t gmp.go:205:2: call mpz_init C value func(mpz_ptr) void gmp.go:206:2: call mpz_set C value func(mpz_ptr, mpz_srcptr) void gmp.go:221:2: call mpz_init C value func(mpz_ptr) void gmp.go:227:7: call size_t C type size_t gmp.go:228:2: call mpz_export C value func(*void, *size_t, int, size_t, int, size_t, mpz_srcptr) *void gmp.go:235:13: call mpz_sizeinbase C value func(mpz_srcptr, int) size_t gmp.go:241:2: call mpz_set C value func(mpz_ptr, mpz_srcptr) void gmp.go:252:3: call mpz_import C value func(mpz_ptr, size_t, int, size_t, int, size_t, *const void) void gmp.go:261:2: call mpz_set_si C value func(mpz_ptr, long int) void gmp.go:273:5: call mpz_set_str C value func(mpz_ptr, *const char, int) int gmp.go:282:9: call mpz_get_str C value func(*char, int, mpz_srcptr) *char gmp.go:287:3: call mpz_clear C value func(mpz_ptr) void gmp.go:302:2: call mpz_add C value func(mpz_ptr, mpz_srcptr, mpz_srcptr) void gmp.go:311:2: call mpz_sub C value func(mpz_ptr, mpz_srcptr, mpz_srcptr) void gmp.go:320:2: call mpz_mul C value func(mpz_ptr, mpz_srcptr, mpz_srcptr) void gmp.go:329:2: call mpz_tdiv_q C value func(mpz_ptr, mpz_srcptr, mpz_srcptr) void gmp.go:339:2: call mpz_tdiv_r C value func(mpz_ptr, mpz_srcptr, mpz_srcptr) void gmp.go:348:2: call mpz_mul_2exp C value func(mpz_ptr, mpz_srcptr, long unsigned int) void gmp.go:356:2: call mpz_div_2exp C value func(mpz_ptr, mpz_srcptr, long unsigned int) void gmp.go:367:3: call mpz_pow_ui C value func(mpz_ptr, mpz_srcptr, long unsigned int) void gmp.go:369:3: call mpz_powm C value func(mpz_ptr, mpz_srcptr, mpz_srcptr, mpz_srcptr) void gmp.go:378:2: call mpz_neg C value func(mpz_ptr, mpz_srcptr) void gmp.go:386:2: call mpz_abs C value func(mpz_ptr, mpz_srcptr) void gmp.go:404:9: call mpz_cmp C value func(mpz_srcptr, mpz_srcptr) int gmp.go:413:2: call mpz_tdiv_qr C value func(mpz_ptr, mpz_ptr, mpz_srcptr, mpz_srcptr) void gmp.go:426:2: call mpz_gcdext C value func(mpz_ptr, mpz_ptr, mpz_ptr, mpz_srcptr, mpz_srcptr) void R=r DELTA=938 (628 added, 308 deleted, 2 changed) OCL=34733 CL=34791
This commit is contained in:
Russ Cox
parent
92f773dc77
commit
6a2602de91
7 changed files with 638 additions and 310 deletions
203
src/cmd/cgo/gcc.go
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203
src/cmd/cgo/gcc.go
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@ -0,0 +1,203 @@
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// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Annotate Crefs in Prog with C types by parsing gcc debug output.
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package main
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import (
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"debug/dwarf";
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"debug/elf";
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"debug/macho";
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"fmt";
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"os";
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"strconv";
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"strings";
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)
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func (p *Prog) loadDebugInfo() {
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// Construct a slice of unique names from p.Crefs.
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m := make(map[string]int);
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for _, c := range p.Crefs {
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m[c.Name] = -1;
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}
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names := make([]string, 0, len(m));
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for name, _ := range m {
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i := len(names);
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names = names[0:i+1];
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names[i] = name;
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m[name] = i;
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}
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// Coerce gcc into telling us whether each name is
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// a type, a value, or undeclared. We compile a function
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// containing the line:
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// name;
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// If name is a type, gcc will print:
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// x.c:2: warning: useless type name in empty declaration
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// If name is a value, gcc will print
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// x.c:2: warning: statement with no effect
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// If name is undeclared, gcc will print
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// x.c:2: error: 'name' undeclared (first use in this function)
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// A line number directive causes the line number to
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// correspond to the index in the names array.
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var b strings.Buffer;
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b.WriteString(p.Preamble);
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b.WriteString("void f(void) {\n");
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b.WriteString("#line 0 \"cgo-test\"\n");
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for _, n := range names {
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b.WriteString(n);
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b.WriteString(";\n");
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}
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b.WriteString("}\n");
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kind := make(map[string]string);
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_, stderr := gccDebug(b.Bytes());
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if stderr == "" {
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fatal("gcc produced no output");
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}
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for _, line := range strings.Split(stderr, "\n", 0) {
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if len(line) < 9 || line[0:9] != "cgo-test:" {
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continue;
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}
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line = line[9:len(line)];
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colon := strings.Index(line, ":");
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if colon < 0 {
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continue;
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}
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i, err := strconv.Atoi(line[0:colon]);
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if err != nil {
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continue;
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}
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what := "";
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switch {
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default:
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continue;
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case strings.Index(line, "warning: useless type name in empty declaration") >= 0:
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what = "type";
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case strings.Index(line, "warning: statement with no effect") >= 0:
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what = "value";
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case strings.Index(line, "undeclared") >= 0:
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what = "error";
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}
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if old, ok := kind[names[i]]; ok && old != what {
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error(noPos, "inconsistent gcc output about C.%s", names[i]);
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}
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kind[names[i]] = what;
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}
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for _, n := range names {
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if _, ok := kind[n]; !ok {
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error(noPos, "could not determine kind of name for C.%s", n);
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}
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}
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// Extract the types from the DWARF section of an object
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// from a well-formed C program. Gcc only generates DWARF info
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// for symbols in the object file, so it is not enough to print the
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// preamble and hope the symbols we care about will be there.
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// Instead, emit
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// typeof(names[i]) *__cgo__i;
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// for each entry in names and then dereference the type we
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// learn for __cgo__i.
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b.Reset();
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b.WriteString(p.Preamble);
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for i, n := range names {
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fmt.Fprintf(&b, "typeof(%s) *__cgo__%d;\n", n, i);
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}
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d, stderr := gccDebug(b.Bytes());
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if d == nil {
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fatal("gcc failed:\n%s\non input:\n%s", stderr, b.Bytes());
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}
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// Scan DWARF info for top-level TagVariable entries with AttrName __cgo__i.
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types := make([]dwarf.Type, len(names));
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r := d.Reader();
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for {
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e, err := r.Next();
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if err != nil {
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fatal("reading DWARF entry: %s", err);
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}
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if e == nil {
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break;
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}
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if e.Tag != dwarf.TagVariable {
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goto Continue;
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}
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name, _ := e.Val(dwarf.AttrName).(string);
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typOff, _ := e.Val(dwarf.AttrType).(dwarf.Offset);
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if name == "" || typOff == 0 {
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fatal("malformed DWARF TagVariable entry");
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}
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if !strings.HasPrefix(name, "__cgo__") {
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goto Continue;
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}
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typ, err := d.Type(typOff);
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if err != nil {
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fatal("loading DWARF type: %s", err);
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}
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t, ok := typ.(*dwarf.PtrType);
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if !ok || t == nil {
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fatal("internal error: %s has non-pointer type", name);
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}
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i, err := strconv.Atoi(name[7:len(name)]);
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if err != nil {
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fatal("malformed __cgo__ name: %s", name);
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}
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types[i] = t.Type;
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Continue:
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if e.Tag != dwarf.TagCompileUnit {
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r.SkipChildren();
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}
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}
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// Apply types to Crefs.
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for _, c := range p.Crefs {
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i := m[c.Name];
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c.TypeName = kind[c.Name] == "type";
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c.DebugType = types[i];
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}
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}
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// gccDebug runs gcc -gdwarf-2 over the C program stdin and
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// returns the corresponding DWARF data and any messages
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// printed to standard error.
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func gccDebug(stdin []byte) (*dwarf.Data, string) {
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machine := "-m32";
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if os.Getenv("GOARCH") == "amd64" {
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machine = "-m64";
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}
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tmp := "_cgo_.o";
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_, stderr, ok := run(stdin, []string{
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"gcc",
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machine,
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"-Wall", // many warnings
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"-Werror", // warnings are errors
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"-o"+tmp, // write object to tmp
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"-gdwarf-2", // generate DWARF v2 debugging symbols
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"-c", // do not link
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"-xc", // input language is C
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"-", // read input from standard input
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});
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if !ok {
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return nil, string(stderr);
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}
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// Try to parse f as ELF and Mach-O and hope one works.
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var f interface{DWARF() (*dwarf.Data, os.Error)};
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var err os.Error;
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if f, err = elf.Open(tmp); err != nil {
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if f, err = macho.Open(tmp); err != nil {
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fatal("cannot parse gcc output %s as ELF or Mach-O object", tmp);
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}
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}
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d, err := f.DWARF();
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if err != nil {
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fatal("cannot load DWARF debug information from %s: %s", tmp, err);
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}
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return d, "";
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}
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