cmd/cgo: add AIX operating system

This commit adds AIX operating system to cmd/cgo package for ppc64
architecture.

It doesn't fully adapt cgo tool to AIX. But it allows to use
go tool cgo -godefs which is really usefull for others packages.

Update: #25893

Change-Id: I38e289cf0122d143ba100986d08229b51b03ddfc
Reviewed-on: https://go-review.googlesource.com/c/138731
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

src/cmd/cgo/gcc.go

@@ -9,6 +9,7 @@ package main
 
 import (
 	"bytes"
+	"cmd/internal/xcoff"
 	"debug/dwarf"
 	"debug/elf"
 	"debug/macho"
@@ -1395,6 +1396,9 @@ func (p *Package) gccCmd() []string {
 
 	c = append(c, p.GccOptions...)
 	c = append(c, p.gccMachine()...)
+	if goos == "aix" {
+		c = append(c, "-maix64")
+	}
 	c = append(c, "-") //read input from standard input
 	return c
 }
@@ -1681,7 +1685,77 @@ func (p *Package) gccDebug(stdin []byte, nnames int) (d *dwarf.Data, ints []int6
 		return d, ints, floats, strs
 	}
 
-	fatalf("cannot parse gcc output %s as ELF, Mach-O, PE object", gccTmp())
+	if f, err := xcoff.Open(gccTmp()); err == nil {
+		defer f.Close()
+		d, err := f.DWARF()
+		if err != nil {
+			fatalf("cannot load DWARF output from %s: %v", gccTmp(), err)
+		}
+		bo := binary.BigEndian
+		for _, s := range f.Symbols {
+			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:]
+							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:]))
+							}
+						}
+					}
+				}
+			default:
+				if n := indexOfDebugStr(s.Name); n != -1 {
+					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:]
+								strdata[n] = string(data)
+							}
+						}
+					}
+					break
+				}
+				if n := indexOfDebugStrlen(s.Name); n != -1 {
+					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:]
+								strlen := bo.Uint64(data[:8])
+								if strlen > (1<<(uint(p.IntSize*8)-1) - 1) { // greater than MaxInt?
+									fatalf("string literal too big")
+								}
+								strlens[n] = int(strlen)
+							}
+						}
+					}
+					break
+				}
+			}
+		}
+
+		buildStrings()
+		return d, ints, floats, strs
+	}
+	fatalf("cannot parse gcc output %s as ELF, Mach-O, PE, XCOFF object", gccTmp())
 	panic("not reached")
 }
 

src/cmd/cgo/out.go

@@ -6,6 +6,7 @@ package main
 
 import (
 	"bytes"
+	"cmd/internal/xcoff"
 	"debug/elf"
 	"debug/macho"
 	"debug/pe"
@@ -312,7 +313,25 @@ func dynimport(obj string) {
 		return
 	}
 
-	fatalf("cannot parse %s as ELF, Mach-O or PE", obj)
+	if f, err := xcoff.Open(obj); err == nil {
+		sym, err := f.ImportedSymbols()
+		if err != nil {
+			fatalf("cannot load imported symbols from XCOFF file %s: %v", obj, err)
+		}
+		for _, s := range sym {
+			fmt.Fprintf(stdout, "//go:cgo_import_dynamic %s %s %q\n", s.Name, s.Name, s.Library)
+		}
+		lib, err := f.ImportedLibraries()
+		if err != nil {
+			fatalf("cannot load imported libraries from XCOFF file %s: %v", obj, err)
+		}
+		for _, l := range lib {
+			fmt.Fprintf(stdout, "//go:cgo_import_dynamic _ _ %q\n", l)
+		}
+		return
+	}
+
+	fatalf("cannot parse %s as ELF, Mach-O, PE or XCOFF", obj)
 }
 
 // Construct a gcc struct matching the gc argument frame.