blob: 432c003b9ad90cb83d4aa3898d81a3e6d540f623 [file] [log] [blame]
// Copyright 2009 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 gc
import (
"cmd/compile/internal/base"
"cmd/compile/internal/ir"
"cmd/compile/internal/noder"
"cmd/compile/internal/objw"
"cmd/compile/internal/reflectdata"
"cmd/compile/internal/staticdata"
"cmd/compile/internal/typecheck"
"cmd/compile/internal/types"
"cmd/internal/archive"
"cmd/internal/bio"
"cmd/internal/obj"
"cmd/internal/objabi"
"encoding/json"
"fmt"
)
// These modes say which kind of object file to generate.
// The default use of the toolchain is to set both bits,
// generating a combined compiler+linker object, one that
// serves to describe the package to both the compiler and the linker.
// In fact the compiler and linker read nearly disjoint sections of
// that file, though, so in a distributed build setting it can be more
// efficient to split the output into two files, supplying the compiler
// object only to future compilations and the linker object only to
// future links.
//
// By default a combined object is written, but if -linkobj is specified
// on the command line then the default -o output is a compiler object
// and the -linkobj output is a linker object.
const (
modeCompilerObj = 1 << iota
modeLinkerObj
)
func dumpobj() {
if base.Flag.LinkObj == "" {
dumpobj1(base.Flag.LowerO, modeCompilerObj|modeLinkerObj)
return
}
dumpobj1(base.Flag.LowerO, modeCompilerObj)
dumpobj1(base.Flag.LinkObj, modeLinkerObj)
}
func dumpobj1(outfile string, mode int) {
bout, err := bio.Create(outfile)
if err != nil {
base.FlushErrors()
fmt.Printf("can't create %s: %v\n", outfile, err)
base.ErrorExit()
}
defer bout.Close()
bout.WriteString("!<arch>\n")
if mode&modeCompilerObj != 0 {
start := startArchiveEntry(bout)
dumpCompilerObj(bout)
finishArchiveEntry(bout, start, "__.PKGDEF")
}
if mode&modeLinkerObj != 0 {
start := startArchiveEntry(bout)
dumpLinkerObj(bout)
finishArchiveEntry(bout, start, "_go_.o")
}
}
func printObjHeader(bout *bio.Writer) {
bout.WriteString(objabi.HeaderString())
if base.Flag.BuildID != "" {
fmt.Fprintf(bout, "build id %q\n", base.Flag.BuildID)
}
if types.LocalPkg.Name == "main" {
fmt.Fprintf(bout, "main\n")
}
fmt.Fprintf(bout, "\n") // header ends with blank line
}
func startArchiveEntry(bout *bio.Writer) int64 {
var arhdr [archive.HeaderSize]byte
bout.Write(arhdr[:])
return bout.Offset()
}
func finishArchiveEntry(bout *bio.Writer, start int64, name string) {
bout.Flush()
size := bout.Offset() - start
if size&1 != 0 {
bout.WriteByte(0)
}
bout.MustSeek(start-archive.HeaderSize, 0)
var arhdr [archive.HeaderSize]byte
archive.FormatHeader(arhdr[:], name, size)
bout.Write(arhdr[:])
bout.Flush()
bout.MustSeek(start+size+(size&1), 0)
}
func dumpCompilerObj(bout *bio.Writer) {
printObjHeader(bout)
noder.WriteExports(bout)
}
func dumpdata() {
numExterns := len(typecheck.Target.Externs)
numDecls := len(typecheck.Target.Decls)
dumpglobls(typecheck.Target.Externs)
reflectdata.CollectPTabs()
numExports := len(typecheck.Target.Exports)
addsignats(typecheck.Target.Externs)
reflectdata.WriteRuntimeTypes()
reflectdata.WriteTabs()
numPTabs := reflectdata.CountPTabs()
reflectdata.WriteImportStrings()
reflectdata.WriteBasicTypes()
dumpembeds()
// Calls to WriteRuntimeTypes can generate functions,
// like method wrappers and hash and equality routines.
// Compile any generated functions, process any new resulting types, repeat.
// This can't loop forever, because there is no way to generate an infinite
// number of types in a finite amount of code.
// In the typical case, we loop 0 or 1 times.
// It was not until issue 24761 that we found any code that required a loop at all.
for {
for i := numDecls; i < len(typecheck.Target.Decls); i++ {
if n, ok := typecheck.Target.Decls[i].(*ir.Func); ok {
enqueueFunc(n)
}
}
numDecls = len(typecheck.Target.Decls)
compileFunctions()
reflectdata.WriteRuntimeTypes()
if numDecls == len(typecheck.Target.Decls) {
break
}
}
// Dump extra globals.
dumpglobls(typecheck.Target.Externs[numExterns:])
if reflectdata.ZeroSize > 0 {
zero := base.PkgLinksym("go.map", "zero", obj.ABI0)
objw.Global(zero, int32(reflectdata.ZeroSize), obj.DUPOK|obj.RODATA)
zero.Set(obj.AttrStatic, true)
}
staticdata.WriteFuncSyms()
addGCLocals()
if numExports != len(typecheck.Target.Exports) {
base.Fatalf("Target.Exports changed after compile functions loop")
}
newNumPTabs := reflectdata.CountPTabs()
if newNumPTabs != numPTabs {
base.Fatalf("ptabs changed after compile functions loop")
}
}
func dumpLinkerObj(bout *bio.Writer) {
printObjHeader(bout)
if len(typecheck.Target.CgoPragmas) != 0 {
// write empty export section; must be before cgo section
fmt.Fprintf(bout, "\n$$\n\n$$\n\n")
fmt.Fprintf(bout, "\n$$ // cgo\n")
if err := json.NewEncoder(bout).Encode(typecheck.Target.CgoPragmas); err != nil {
base.Fatalf("serializing pragcgobuf: %v", err)
}
fmt.Fprintf(bout, "\n$$\n\n")
}
fmt.Fprintf(bout, "\n!\n")
obj.WriteObjFile(base.Ctxt, bout)
}
func dumpGlobal(n *ir.Name) {
if n.Type() == nil {
base.Fatalf("external %v nil type\n", n)
}
if n.Class == ir.PFUNC {
return
}
if n.Sym().Pkg != types.LocalPkg {
return
}
types.CalcSize(n.Type())
ggloblnod(n)
base.Ctxt.DwarfGlobal(base.Ctxt.Pkgpath, types.TypeSymName(n.Type()), n.Linksym())
}
func dumpGlobalConst(n ir.Node) {
// only export typed constants
t := n.Type()
if t == nil {
return
}
if n.Sym().Pkg != types.LocalPkg {
return
}
// only export integer constants for now
if !t.IsInteger() {
return
}
v := n.Val()
if t.IsUntyped() {
// Export untyped integers as int (if they fit).
t = types.Types[types.TINT]
if ir.ConstOverflow(v, t) {
return
}
}
base.Ctxt.DwarfIntConst(base.Ctxt.Pkgpath, n.Sym().Name, types.TypeSymName(t), ir.IntVal(t, v))
}
func dumpglobls(externs []ir.Node) {
// add globals
for _, n := range externs {
switch n.Op() {
case ir.ONAME:
dumpGlobal(n.(*ir.Name))
case ir.OLITERAL:
dumpGlobalConst(n)
}
}
}
// addGCLocals adds gcargs, gclocals, gcregs, and stack object symbols to Ctxt.Data.
//
// This is done during the sequential phase after compilation, since
// global symbols can't be declared during parallel compilation.
func addGCLocals() {
for _, s := range base.Ctxt.Text {
fn := s.Func()
if fn == nil {
continue
}
for _, gcsym := range []*obj.LSym{fn.GCArgs, fn.GCLocals} {
if gcsym != nil && !gcsym.OnList() {
objw.Global(gcsym, int32(len(gcsym.P)), obj.RODATA|obj.DUPOK)
}
}
if x := fn.StackObjects; x != nil {
attr := int16(obj.RODATA)
objw.Global(x, int32(len(x.P)), attr)
x.Set(obj.AttrStatic, true)
}
if x := fn.OpenCodedDeferInfo; x != nil {
objw.Global(x, int32(len(x.P)), obj.RODATA|obj.DUPOK)
}
if x := fn.ArgInfo; x != nil {
objw.Global(x, int32(len(x.P)), obj.RODATA|obj.DUPOK)
x.Set(obj.AttrStatic, true)
}
}
}
func ggloblnod(nam *ir.Name) {
s := nam.Linksym()
s.Gotype = reflectdata.TypeLinksym(nam.Type())
flags := 0
if nam.Readonly() {
flags = obj.RODATA
}
if nam.Type() != nil && !nam.Type().HasPointers() {
flags |= obj.NOPTR
}
base.Ctxt.Globl(s, nam.Type().Size(), flags)
if nam.LibfuzzerExtraCounter() {
s.Type = objabi.SLIBFUZZER_EXTRA_COUNTER
}
if nam.Sym().Linkname != "" {
// Make sure linkname'd symbol is non-package. When a symbol is
// both imported and linkname'd, s.Pkg may not set to "_" in
// types.Sym.Linksym because LSym already exists. Set it here.
s.Pkg = "_"
}
}
func dumpembeds() {
for _, v := range typecheck.Target.Embeds {
staticdata.WriteEmbed(v)
}
}
func addsignats(dcls []ir.Node) {
// copy types from dcl list to signatset
for _, n := range dcls {
if n.Op() == ir.OTYPE {
reflectdata.NeedRuntimeType(n.Type())
}
}
}