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cmd/cgo: support floating point #define macros

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Current code doesn't support floating point #define macros.
This CL compiles floats to a object file and retrive values from it.
That approach is the same work as we've already done for integers.

Updates #18720

Change-Id: I88b7ab174d0f73bda975cf90c5aeb797961fe034
Reviewed-on: https://go-review.googlesource.com/35511
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This commit is contained in:
Hiroshi Ioka 2017-01-20 08:34:18 +09:00 • committed by Ian Lance Taylor
parent 735fe51a4b
commit 89ff0b1b6b
4 changed files with 163 additions and 65 deletions
Download patch file Download diff file Expand all files Collapse all files

202
src/cmd/cgo/gcc.go
View file

@ -20,6 +20,7 @@ import (
"go/ast"
"go/parser"
"go/token"
"math"
"os"
"strconv"
"strings"
@ -241,26 +242,26 @@ func (p *Package) guessKinds(f *File) []*Name {
// If we've already found this name as a #define
// and we can translate it as a constant value, do so.
if n.Define != "" {
isConst := false
if _, err := strconv.Atoi(n.Define); err == nil {
isConst = true
} else if n.Define[0] == '"' || n.Define[0] == '\'' {
if _, err := parser.ParseExpr(n.Define); err == nil {
isConst = true
}
}
if isConst {
n.Kind = "const"
if i, err := strconv.ParseInt(n.Define, 0, 64); err == nil {
n.Kind = "iconst"
// Turn decimal into hex, just for consistency
// with enum-derived constants. Otherwise
// in the cgo -godefs output half the constants
// are in hex and half are in whatever the #define used.
i, err := strconv.ParseInt(n.Define, 0, 64)
if err == nil {
n.Const = fmt.Sprintf("%#x", i)
} else {
n.Const = fmt.Sprintf("%#x", i)
} else if n.Define[0] == '\'' {
if _, err := parser.ParseExpr(n.Define); err == nil {
n.Kind = "iconst"
n.Const = n.Define
}
} else if n.Define[0] == '"' {
if _, err := parser.ParseExpr(n.Define); err == nil {
n.Kind = "sconst"
n.Const = n.Define
}
}
if n.IsConst() {
continue
}
@ -298,14 +299,18 @@ func (p *Package) guessKinds(f *File) []*Name {
// void __cgo_f_xxx_1(void) { __typeof__(name) *__cgo_undefined__; }
// #line xxx "not-type"
// void __cgo_f_xxx_2(void) { name *__cgo_undefined__; }
// #line xxx "not-const"
// #line xxx "not-int-const"
// void __cgo_f_xxx_3(void) { enum { __cgo_undefined__ = (name)*1 }; }
// #line xxx "not-num-const"
// void __cgo_f_xxx_4(void) { static const double x = (name); }
// #line xxx "not-str-lit"
// void __cgo_f_xxx_5(void) { static const char x[] = (name); }
//
// If we see an error at not-declared:xxx, the corresponding name is not declared.
// If we see an error at not-type:xxx, the corresponding name is a type.
// If we see an error at not-const:xxx, the corresponding name is not an integer constant.
// If we see no errors, we assume the name is an expression but not a constant
// (so a variable or a function).
// If we see an error at not-int-const:xxx, the corresponding name is not an integer constant.
// If we see an error at not-num-const:xxx, the corresponding name is not a number constant.
// If we see an error at not-str-lit:xxx, the corresponding name is not a string literal.
//
// The specific input forms are chosen so that they are valid C syntax regardless of
// whether name denotes a type or an expression.
@ -319,8 +324,14 @@ func (p *Package) guessKinds(f *File) []*Name {
"void __cgo_f_%d_1(void) { __typeof__(%s) *__cgo_undefined__; }\n"+
"#line %d \"not-type\"\n"+
"void __cgo_f_%d_2(void) { %s *__cgo_undefined__; }\n"+
"#line %d \"not-const\"\n"+
"void __cgo_f_%d_3(void) { enum { __cgo__undefined__ = (%s)*1 }; }\n",
"#line %d \"not-int-const\"\n"+
"void __cgo_f_%d_3(void) { enum { __cgo_undefined__ = (%s)*1 }; }\n"+
"#line %d \"not-num-const\"\n"+
"void __cgo_f_%d_4(void) { static const double x = (%s); }\n"+
"#line %d \"not-str-lit\"\n"+
"void __cgo_f_%d_5(void) { static const char s[] = (%s); }\n",
i+1, i+1, n.C,
i+1, i+1, n.C,
i+1, i+1, n.C,
i+1, i+1, n.C,
i+1, i+1, n.C)
@ -337,7 +348,9 @@ func (p *Package) guessKinds(f *File) []*Name {
sniff := make([]int, len(names))
const (
notType = 1 << iota
notConst
notIntConst
notNumConst
notStrLiteral
notDeclared
)
for _, line := range strings.Split(stderr, "\n") {
@ -376,8 +389,12 @@ func (p *Package) guessKinds(f *File) []*Name {
sniff[i] |= notDeclared
case "not-type":
sniff[i] |= notType
case "not-const":
sniff[i] |= notConst
case "not-int-const":
sniff[i] |= notIntConst
case "not-num-const":
sniff[i] |= notNumConst
case "not-str-lit":
sniff[i] |= notStrLiteral
}
}
@ -389,11 +406,15 @@ func (p *Package) guessKinds(f *File) []*Name {
switch sniff[i] {
default:
error_(token.NoPos, "could not determine kind of name for C.%s", fixGo(n.Go))
case notType:
n.Kind = "const"
case notConst:
case notStrLiteral | notType:
n.Kind = "iconst"
case notIntConst | notStrLiteral | notType:
n.Kind = "fconst"
case notIntConst | notNumConst | notType:
n.Kind = "sconst"
case notIntConst | notNumConst | notStrLiteral:
n.Kind = "type"
case notConst | notType:
case notIntConst | notNumConst | notStrLiteral | notType:
n.Kind = "not-type"
}
}
@ -431,7 +452,7 @@ func (p *Package) loadDWARF(f *File, names []*Name) {
b.WriteString("#line 1 \"cgo-dwarf-inference\"\n")
for i, n := range names {
fmt.Fprintf(&b, "__typeof__(%s) *__cgo__%d;\n", n.C, i)
if n.Kind == "const" {
if n.Kind == "iconst" {
fmt.Fprintf(&b, "enum { __cgo_enum__%d = %s };\n", i, n.C)
}
}
@ -440,9 +461,9 @@ func (p *Package) loadDWARF(f *File, names []*Name) {
// names and values in its DWARF debug output. In case we're
// using such a gcc, create a data block initialized with the values.
// We can read them out of the object file.
fmt.Fprintf(&b, "long long __cgodebug_data[] = {\n")
fmt.Fprintf(&b, "long long __cgodebug_ints[] = {\n")
for _, n := range names {
if n.Kind == "const" {
if n.Kind == "iconst" {
fmt.Fprintf(&b, "\t%s,\n", n.C)
} else {
fmt.Fprintf(&b, "\t0,\n")
@ -456,11 +477,19 @@ func (p *Package) loadDWARF(f *File, names []*Name) {
fmt.Fprintf(&b, "\t1\n")
fmt.Fprintf(&b, "};\n")
d, bo, debugData := p.gccDebug(b.Bytes())
enumVal := make([]int64, len(debugData)/8)
for i := range enumVal {
enumVal[i] = int64(bo.Uint64(debugData[i*8:]))
// do the same work for floats.
fmt.Fprintf(&b, "double __cgodebug_floats[] = {\n")
for _, n := range names {
if n.Kind == "fconst" {
fmt.Fprintf(&b, "\t%s,\n", n.C)
} else {
fmt.Fprintf(&b, "\t0,\n")
}
}
fmt.Fprintf(&b, "\t1\n")
fmt.Fprintf(&b, "};\n")
d, ints, floats := p.gccDebug(b.Bytes())
// Scan DWARF info for top-level TagVariable entries with AttrName __cgo__i.
types := make([]dwarf.Type, len(names))
@ -563,15 +592,22 @@ func (p *Package) loadDWARF(f *File, names []*Name) {
n.Type = conv.Type(types[i], pos)
if enums[i] != 0 && n.Type.EnumValues != nil {
k := fmt.Sprintf("__cgo_enum__%d", i)
n.Kind = "const"
n.Kind = "iconst"
n.Const = fmt.Sprintf("%#x", n.Type.EnumValues[k])
// Remove injected enum to ensure the value will deep-compare
// equally in future loads of the same constant.
delete(n.Type.EnumValues, k)
}
// Prefer debug data over DWARF debug output, if we have it.
if n.Kind == "const" && i < len(enumVal) {
n.Const = fmt.Sprintf("%#x", enumVal[i])
switch n.Kind {
case "iconst":
if i < len(ints) {
n.Const = fmt.Sprintf("%#x", ints[i])
}
case "fconst":
if i < len(floats) {
n.Const = fmt.Sprintf("%f", floats[i])
}
}
}
conv.FinishType(pos)
@ -1050,7 +1086,7 @@ func (p *Package) rewriteRef(f *File) {
// are trying to do a ,err call. Also check that
// functions are only used in calls.
for _, r := range f.Ref {
if r.Name.Kind == "const" && r.Name.Const == "" {
if r.Name.IsConst() && r.Name.Const == "" {
error_(r.Pos(), "unable to find value of constant C.%s", fixGo(r.Name.Go))
}
var expr ast.Expr = ast.NewIdent(r.Name.Mangle) // default
@ -1258,12 +1294,16 @@ func (p *Package) gccCmd() []string {
// gccDebug runs gcc -gdwarf-2 over the C program stdin and
// returns the corresponding DWARF data and, if present, debug data block.
func (p *Package) gccDebug(stdin []byte) (*dwarf.Data, binary.ByteOrder, []byte) {
func (p *Package) gccDebug(stdin []byte) (d *dwarf.Data, ints []int64, floats []float64) {
runGcc(stdin, p.gccCmd())
isDebugData := func(s string) bool {
isDebugInts := func(s string) bool {
// Some systems use leading _ to denote non-assembly symbols.
return s == "__cgodebug_data" || s == "___cgodebug_data"
return s == "__cgodebug_ints" || s == "___cgodebug_ints"
}
isDebugFloats := func(s string) bool {
// Some systems use leading _ to denote non-assembly symbols.
return s == "__cgodebug_floats" || s == "___cgodebug_floats"
}
if f, err := macho.Open(gccTmp()); err == nil {
@ -1272,24 +1312,43 @@ func (p *Package) gccDebug(stdin []byte) (*dwarf.Data, binary.ByteOrder, []byte)
if err != nil {
fatalf("cannot load DWARF output from %s: %v", gccTmp(), err)
}
var data []byte
bo := f.ByteOrder
if f.Symtab != nil {
for i := range f.Symtab.Syms {
s := &f.Symtab.Syms[i]
if isDebugData(s.Name) {
switch {
case isDebugInts(s.Name):
// Found it. Now find data section.
if i := int(s.Sect) - 1; 0 <= i && i < len(f.Sections) {
sect := f.Sections[i]
if sect.Addr <= s.Value && s.Value < sect.Addr+sect.Size {
if sdat, err := sect.Data(); err == nil {
data = sdat[s.Value-sect.Addr:]
data := sdat[s.Value-sect.Addr:]
ints = make([]int64, len(data)/8)
for i := range ints {
ints[i] = int64(bo.Uint64(data[i*8:]))
}
}
}
}
case isDebugFloats(s.Name):
// Found it. Now find data section.
if i := int(s.Sect) - 1; 0 <= i && i < len(f.Sections) {
sect := f.Sections[i]
if sect.Addr <= s.Value && s.Value < sect.Addr+sect.Size {
if sdat, err := sect.Data(); err == nil {
data := sdat[s.Value-sect.Addr:]
floats = make([]float64, len(data)/8)
for i := range floats {
floats[i] = math.Float64frombits(bo.Uint64(data[i*8:]))
}
}
}
}
}
}
}
return d, f.ByteOrder, data
return d, ints, floats
}
if f, err := elf.Open(gccTmp()); err == nil {
@ -1298,25 +1357,44 @@ func (p *Package) gccDebug(stdin []byte) (*dwarf.Data, binary.ByteOrder, []byte)
if err != nil {
fatalf("cannot load DWARF output from %s: %v", gccTmp(), err)
}
var data []byte
bo := f.ByteOrder
symtab, err := f.Symbols()
if err == nil {
for i := range symtab {
s := &symtab[i]
if isDebugData(s.Name) {
switch {
case isDebugInts(s.Name):
// Found it. Now find data section.
if i := int(s.Section); 0 <= i && i < len(f.Sections) {
sect := f.Sections[i]
if sect.Addr <= s.Value && s.Value < sect.Addr+sect.Size {
if sdat, err := sect.Data(); err == nil {
data = sdat[s.Value-sect.Addr:]
data := sdat[s.Value-sect.Addr:]
ints = make([]int64, len(data)/8)
for i := range ints {
ints[i] = int64(bo.Uint64(data[i*8:]))
}
}
}
}
case isDebugFloats(s.Name):
// Found it. Now find data section.
if i := int(s.Section); 0 <= i && i < len(f.Sections) {
sect := f.Sections[i]
if sect.Addr <= s.Value && s.Value < sect.Addr+sect.Size {
if sdat, err := sect.Data(); err == nil {
data := sdat[s.Value-sect.Addr:]
floats = make([]float64, len(data)/8)
for i := range floats {
floats[i] = math.Float64frombits(bo.Uint64(data[i*8:]))
}
}
}
}
}
}
}
return d, f.ByteOrder, data
return d, ints, floats
}
if f, err := pe.Open(gccTmp()); err == nil {
@ -1325,20 +1403,38 @@ func (p *Package) gccDebug(stdin []byte) (*dwarf.Data, binary.ByteOrder, []byte)
if err != nil {
fatalf("cannot load DWARF output from %s: %v", gccTmp(), err)
}
var data []byte
bo := binary.LittleEndian
for _, s := range f.Symbols {
if isDebugData(s.Name) {
switch {
case isDebugInts(s.Name):
if i := int(s.SectionNumber) - 1; 0 <= i && i < len(f.Sections) {
sect := f.Sections[i]
if s.Value < sect.Size {
if sdat, err := sect.Data(); err == nil {
data = sdat[s.Value:]
data := sdat[s.Value:]
ints = make([]int64, len(data)/8)
for i := range ints {
ints[i] = int64(bo.Uint64(data[i*8:]))
}
}
}
}
case isDebugFloats(s.Name):
if i := int(s.SectionNumber) - 1; 0 <= i && i < len(f.Sections) {
sect := f.Sections[i]
if s.Value < sect.Size {
if sdat, err := sect.Data(); err == nil {
data := sdat[s.Value:]
floats = make([]float64, len(data)/8)
for i := range floats {
floats[i] = math.Float64frombits(bo.Uint64(data[i*8:]))
}
}
}
}
}
}
return d, binary.LittleEndian, data
return d, ints, floats
}
fatalf("cannot parse gcc output %s as ELF, Mach-O, PE object", gccTmp())