qbit/go
1
0
Fork 0
mirror of https://github.com/golang/go synced 2024-11-19 00:44:40 -07:00
Code Releases Activity

cmd/compile: update object file format for DWARF file table

Browse Source 
In CL 188317, we generate the debug_lines in the compiler, and created a
new symbol to hold the line table. Here we modify the object file format
to output the file table.

Change-Id: Ibee192e80b86ff6af36467a0b1c26ee747dfee37
Reviewed-on: https://go-review.googlesource.com/c/go/+/191167
Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This commit is contained in:
Jeremy Faller 2019-08-22 12:18:28 -04:00
parent efb9739203
commit 21bf37b5a2
6 changed files with 49 additions and 53 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

25
src/cmd/internal/goobj/read.go
View File

@ -129,13 +129,14 @@ type InlinedCall struct {
// A Package is a parsed Go object file or archive defining a Go package.
type Package struct {
ImportPath string // import path denoting this package
Imports []string // packages imported by this package
SymRefs []SymID // list of symbol names and versions referred to by this pack
Syms []*Sym // symbols defined by this package
MaxVersion int64 // maximum Version in any SymID in Syms
Arch string // architecture
Native []*NativeReader // native object data (e.g. ELF)
ImportPath string // import path denoting this package
Imports []string // packages imported by this package
SymRefs []SymID // list of symbol names and versions referred to by this pack
Syms []*Sym // symbols defined by this package
MaxVersion int64 // maximum Version in any SymID in Syms
Arch string // architecture
Native []*NativeReader // native object data (e.g. ELF)
DWARFFileList []string // List of files for the DWARF .debug_lines section
}
type NativeReader struct {
@ -502,7 +503,7 @@ func (r *objReader) parseObject(prefix []byte) error {
// TODO: extract OS + build ID if/when we need it
r.readFull(r.tmp[:8])
if !bytes.Equal(r.tmp[:8], []byte("\x00go112ld")) {
if !bytes.Equal(r.tmp[:8], []byte("\x00go114ld")) {
return r.error(errCorruptObject)
}
@ -520,6 +521,12 @@ func (r *objReader) parseObject(prefix []byte) error {
r.p.Imports = append(r.p.Imports, s)
}
// Read filenames for dwarf info.
count := r.readInt()
for i := int64(0); i < count; i++ {
r.p.DWARFFileList = append(r.p.DWARFFileList, r.readString())
}
r.p.SymRefs = []SymID{{"", 0}}
for {
if b := r.readByte(); b != 0xfe {
@ -619,7 +626,7 @@ func (r *objReader) parseObject(prefix []byte) error {
}
r.readFull(r.tmp[:7])
if !bytes.Equal(r.tmp[:7], []byte("go112ld")) {
if !bytes.Equal(r.tmp[:7], []byte("go114ld")) {
return r.error(errCorruptObject)
}

12
src/cmd/internal/obj/dwarf.go
View File

@ -235,15 +235,3 @@ func putpclcdelta(linkctxt *Link, dctxt dwCtxt, s *LSym, deltaPC uint64, deltaLC
// Output the special opcode.
dctxt.AddUint8(s, uint8(opcode))
}
// createDebugLinesFileTable creates a new symbol holding the list of files
// in our package.
func (ctxt *Link) createDebugLinesFileTable() {
dctxt := dwCtxt{ctxt}
fileLUT := ctxt.PosTable.DebugLinesFileTable()
s := ctxt.dwarfFileTableSymbol()
for _, file := range fileLUT {
dctxt.AddString(s, file)
}
}

28
src/cmd/internal/obj/objfile.go
View File

@ -86,7 +86,7 @@ func WriteObjFile(ctxt *Link, b *bufio.Writer, pkgpath string) {
w := newObjWriter(ctxt, b, pkgpath)
// Magic header
w.wr.WriteString("\x00go112ld")
w.wr.WriteString("\x00go114ld")
// Version
w.wr.WriteByte(1)
@ -97,6 +97,13 @@ func WriteObjFile(ctxt *Link, b *bufio.Writer, pkgpath string) {
}
w.writeString("")
// DWARF File Table
fileTable := ctxt.PosTable.DebugLinesFileTable()
w.writeInt(int64(len(fileTable)))
for _, str := range fileTable {
w.writeString(str)
}
// Symbol references
for _, s := range ctxt.Text {
w.writeRefs(s)
@ -161,7 +168,7 @@ func WriteObjFile(ctxt *Link, b *bufio.Writer, pkgpath string) {
}
// Magic footer
w.wr.WriteString("\xffgo112ld")
w.wr.WriteString("\xffgo114ld")
}
// Symbols are prefixed so their content doesn't get confused with the magic footer.
@ -641,23 +648,6 @@ func (ctxt *Link) DwarfIntConst(myimportpath, name, typename string, val int64)
dwarf.PutIntConst(dwCtxt{ctxt}, s, ctxt.Lookup(dwarf.InfoPrefix+typename), myimportpath+"."+name, val)
}
// dwarfFileTableSymbol creates (or finds) the symbol for holding the line table for this package.
//
// The symbol WILL NOT be unique at the per package/archive level. For example,
// when writing a package archive, we'll write this symbol for the Go code, and
// one for each assembly file in the package. As such, we can't treat this
// symbol the same when we read in the object files in the linker. This symbol
// won't make it to the symbol table, and compilation units will keep track of
// it.
// TODO: Actually save this to the object file, and read it back in the linker.
func (ctxt *Link) dwarfFileTableSymbol() *LSym {
s := ctxt.LookupInit(dwarf.DebugLinesPrefix+".package", func(s *LSym) {
s.Type = objabi.SDWARFLINES
//ctxt.Data = append(ctxt.Data, s)
})
return s
}
func (ctxt *Link) DwarfAbstractFunc(curfn interface{}, s *LSym, myimportpath string) {
absfn := ctxt.DwFixups.AbsFuncDwarfSym(s)
if absfn.Size != 0 {

6
src/cmd/internal/objabi/doc.go
View File

@ -22,10 +22,12 @@
//
// The file format is:
//
// - magic header: "\x00go112ld"
// - magic header: "\x00go114ld"
// - byte 1 - version number
// - sequence of strings giving dependencies (imported packages)
// - empty string (marks end of sequence)
// - number of entries in the following sequence
// - sequence of filename strings to generate debug information
// - sequence of symbol references used by the defined symbols
// - byte 0xff (marks end of sequence)
// - sequence of integer lengths:
@ -38,7 +40,7 @@
// - data, the content of the defined symbols
// - sequence of defined symbols
// - byte 0xff (marks end of sequence)
// - magic footer: "\xffgo112ld"
// - magic footer: "\xffgo114ld"
//
// All integers are stored in a zigzag varint format.
// See golang.org/s/go12symtab for a definition.

12
src/cmd/link/internal/objfile/objfile.go
View File

@ -27,8 +27,8 @@ import (
)
const (
startmagic = "\x00go112ld"
endmagic = "\xffgo112ld"
startmagic = "\x00go114ld"
endmagic = "\xffgo114ld"
)
var emptyPkg = []byte(`"".`)
@ -136,6 +136,14 @@ func (r *objReader) loadObjFile() {
r.lib.ImportStrings = append(r.lib.ImportStrings, lib)
}
// DWARF strings
count := r.readInt()
r.unit.DWARFFileTable = make([]string, count)
for i := 0; i < count; i++ {
// TODO: This should probably be a call to mkROString.
r.unit.DWARFFileTable[i] = r.readString()
}
// Symbol references
r.refs = []*sym.Symbol{nil} // zeroth ref is nil
for {

19
src/cmd/link/internal/sym/compilation_unit.go
View File

@ -10,13 +10,14 @@ import "cmd/internal/dwarf"
// debug-related data. We create a CompilationUnit per Object file in a
// library (so, one for all the Go code, one for each assembly file, etc.).
type CompilationUnit struct {
Pkg string // The package name, eg ("fmt", or "runtime")
Lib *Library // Our library
Consts *Symbol // Package constants DIEs
PCs []dwarf.Range // PC ranges, relative to Textp[0]
DWInfo *dwarf.DWDie // CU root DIE
FuncDIEs []*Symbol // Function DIE subtrees
AbsFnDIEs []*Symbol // Abstract function DIE subtrees
RangeSyms []*Symbol // Symbols for debug_range
Textp []*Symbol // Text symbols in this CU
Pkg string // The package name, eg ("fmt", or "runtime")
Lib *Library // Our library
Consts *Symbol // Package constants DIEs
PCs []dwarf.Range // PC ranges, relative to Textp[0]
DWInfo *dwarf.DWDie // CU root DIE
FuncDIEs []*Symbol // Function DIE subtrees
AbsFnDIEs []*Symbol // Abstract function DIE subtrees
RangeSyms []*Symbol // Symbols for debug_range
Textp []*Symbol // Text symbols in this CU
DWARFFileTable []string // The file table used to generate the .debug_lines
}