diff options
Diffstat (limited to 'src/cmd/link/internal/ld/dwarf.go')
| -rw-r--r-- | src/cmd/link/internal/ld/dwarf.go | 111 |
1 files changed, 76 insertions, 35 deletions
diff --git a/src/cmd/link/internal/ld/dwarf.go b/src/cmd/link/internal/ld/dwarf.go index d1f2ac583d..2ab9a55e96 100644 --- a/src/cmd/link/internal/ld/dwarf.go +++ b/src/cmd/link/internal/ld/dwarf.go @@ -23,6 +23,7 @@ import ( "cmd/link/internal/sym" "fmt" "log" + "path" "runtime" "sort" "strings" @@ -1173,13 +1174,81 @@ func expandFile(fname string) string { return expandGoroot(fname) } -// writelines collects up and chai,ns together the symbols needed to +// writeDirFileTables emits the portion of the DWARF line table +// prologue containing the include directories and file names, +// described in section 6.2.4 of the DWARF 4 standard. It walks the +// filepaths for the unit to discover any common directories, which +// are emitted to the directory table first, then the file table is +// emitted after that. +func (d *dwctxt) writeDirFileTables(unit *sym.CompilationUnit, lsu *loader.SymbolBuilder) { + type fileDir struct { + base string + dir int + } + dirNums := make(map[string]int) + dirs := []string{""} + files := []fileDir{} + + // Preprocess files to collect directories. This assumes that the + // file table is already de-duped. + for i, name := range unit.FileTable { + name := expandFile(name) + if len(name) == 0 { + // Can't have empty filenames, and having a unique + // filename is quite useful for debugging. + name = fmt.Sprintf("<missing>_%d", i) + } + // Note the use of "path" here and not "filepath". The compiler + // hard-codes to use "/" in DWARF paths (even for Windows), so we + // want to maintain that here. + file := path.Base(name) + dir := path.Dir(name) + dirIdx, ok := dirNums[dir] + if !ok && dir != "." { + dirIdx = len(dirNums) + 1 + dirNums[dir] = dirIdx + dirs = append(dirs, dir) + } + files = append(files, fileDir{base: file, dir: dirIdx}) + + // We can't use something that may be dead-code + // eliminated from a binary here. proc.go contains + // main and the scheduler, so it's not going anywhere. + if i := strings.Index(name, "runtime/proc.go"); i >= 0 { + d.dwmu.Lock() + if gdbscript == "" { + k := strings.Index(name, "runtime/proc.go") + gdbscript = name[:k] + "runtime/runtime-gdb.py" + } + d.dwmu.Unlock() + } + } + + // Emit directory section. This is a series of nul terminated + // strings, followed by a single zero byte. + lsDwsym := dwSym(lsu.Sym()) + for k := 1; k < len(dirs); k++ { + d.AddString(lsDwsym, dirs[k]) + } + lsu.AddUint8(0) // terminator + + // Emit file section. + for k := 0; k < len(files); k++ { + d.AddString(lsDwsym, files[k].base) + dwarf.Uleb128put(d, lsDwsym, int64(files[k].dir)) + lsu.AddUint8(0) // mtime + lsu.AddUint8(0) // length + } + lsu.AddUint8(0) // terminator +} + +// writelines collects up and chains together the symbols needed to // form the DWARF line table for the specified compilation unit, // returning a list of symbols. The returned list will include an -// initial symbol containing the line table header and prolog (with +// initial symbol containing the line table header and prologue (with // file table), then a series of compiler-emitted line table symbols // (one per live function), and finally an epilog symbol containing an -// end-of-sequence operator. The prolog and epilog symbols are passed +// end-of-sequence operator. The prologue and epilog symbols are passed // in (having been created earlier); here we add content to them. func (d *dwctxt) writelines(unit *sym.CompilationUnit, lineProlog loader.Sym) []loader.Sym { is_stmt := uint8(1) // initially = recommended default_is_stmt = 1, tracks is_stmt toggles. @@ -1220,39 +1289,11 @@ func (d *dwctxt) writelines(unit *sym.CompilationUnit, lineProlog loader.Sym) [] lsu.AddUint8(0) // standard_opcode_lengths[8] lsu.AddUint8(1) // standard_opcode_lengths[9] lsu.AddUint8(0) // standard_opcode_lengths[10] - lsu.AddUint8(0) // include_directories (empty) - - // Copy over the file table. - fileNums := make(map[string]int) - for i, name := range unit.FileTable { - name := expandFile(name) - if len(name) == 0 { - // Can't have empty filenames, and having a unique - // filename is quite useful for debugging. - name = fmt.Sprintf("<missing>_%d", i) - } - fileNums[name] = i + 1 - d.AddString(lsDwsym, name) - lsu.AddUint8(0) - lsu.AddUint8(0) - lsu.AddUint8(0) - // We can't use something that may be dead-code - // eliminated from a binary here. proc.go contains - // main and the scheduler, so it's not going anywhere. - if i := strings.Index(name, "runtime/proc.go"); i >= 0 { - d.dwmu.Lock() - if gdbscript == "" { - k := strings.Index(name, "runtime/proc.go") - gdbscript = name[:k] + "runtime/runtime-gdb.py" - } - d.dwmu.Unlock() - } - } + // Call helper to emit dir and file sections. + d.writeDirFileTables(unit, lsu) - // 4 zeros: the string termination + 3 fields. - lsu.AddUint8(0) - // terminate file_names. + // capture length at end of file names. headerend = lsu.Size() unitlen := lsu.Size() - unitstart @@ -1421,7 +1462,7 @@ func (d *dwctxt) writeframes(fs loader.Sym) dwarfSecInfo { deltaBuf = dwarf.AppendUleb128(deltaBuf, uint64(thearch.Dwarfreglr)) } - for pcsp.Init(fpcsp); !pcsp.Done; pcsp.Next() { + for pcsp.Init(d.linkctxt.loader.Data(fpcsp)); !pcsp.Done; pcsp.Next() { nextpc := pcsp.NextPC // pciterinit goes up to the end of the function, |