diff options
Diffstat (limited to 'src/cmd/compile/internal/noder/decoder.go')
| -rw-r--r-- | src/cmd/compile/internal/noder/decoder.go | 100 |
1 files changed, 79 insertions, 21 deletions
diff --git a/src/cmd/compile/internal/noder/decoder.go b/src/cmd/compile/internal/noder/decoder.go index 023388875c..3dc61c6a69 100644 --- a/src/cmd/compile/internal/noder/decoder.go +++ b/src/cmd/compile/internal/noder/decoder.go @@ -13,6 +13,7 @@ import ( "go/token" "math/big" "os" + "runtime" "strings" "cmd/compile/internal/base" @@ -131,17 +132,82 @@ func (r *decoder) checkErr(err error) { } } -func (r *decoder) sync(m syncMarker) { - if debug { - pos, err0 := r.data.Seek(0, os.SEEK_CUR) - x, err := r.data.ReadByte() - r.checkErr(err) - if x != byte(m) { - // TODO(mdempsky): Revisit this error message, and make it more - // useful (e.g., include r.p.pkgPath). - base.Fatalf("data sync error: found %v at %v (%v) in (%v:%v), but expected %v", syncMarker(x), pos, err0, r.k, r.idx, m) - } +func (r *decoder) rawUvarint() uint64 { + x, err := binary.ReadUvarint(&r.data) + r.checkErr(err) + return x +} + +func (r *decoder) rawVarint() int64 { + ux := r.rawUvarint() + + // Zig-zag decode. + x := int64(ux >> 1) + if ux&1 != 0 { + x = ^x + } + return x +} + +func (r *decoder) rawReloc(k reloc, idx int) int { + e := r.relocs[idx] + assert(e.kind == k) + return e.idx +} + +func (r *decoder) sync(mWant syncMarker) { + if !enableSync { + return + } + + pos, _ := r.data.Seek(0, os.SEEK_CUR) // TODO(mdempsky): io.SeekCurrent after #44505 is resolved + mHave := syncMarker(r.rawUvarint()) + writerPCs := make([]int, r.rawUvarint()) + for i := range writerPCs { + writerPCs[i] = int(r.rawUvarint()) + } + + if mHave == mWant { + return + } + + // There's some tension here between printing: + // + // (1) full file paths that tools can recognize (e.g., so emacs + // hyperlinks the "file:line" text for easy navigation), or + // + // (2) short file paths that are easier for humans to read (e.g., by + // omitting redundant or irrelevant details, so it's easier to + // focus on the useful bits that remain). + // + // The current formatting favors the former, as it seems more + // helpful in practice. But perhaps the formatting could be improved + // to better address both concerns. For example, use relative file + // paths if they would be shorter, or rewrite file paths to contain + // "$GOROOT" (like objabi.AbsFile does) if tools can be taught how + // to reliably expand that again. + + fmt.Printf("export data desync: package %q, section %v, index %v, offset %v\n", r.common.pkgPath, r.k, r.idx, pos) + + fmt.Printf("\nfound %v, written at:\n", mHave) + if len(writerPCs) == 0 { + fmt.Printf("\t[stack trace unavailable; recompile package %q with -d=syncframes]\n", r.common.pkgPath) } + for _, pc := range writerPCs { + fmt.Printf("\t%s\n", r.common.stringIdx(r.rawReloc(relocString, pc))) + } + + fmt.Printf("\nexpected %v, reading at:\n", mWant) + var readerPCs [32]uintptr // TODO(mdempsky): Dynamically size? + n := runtime.Callers(2, readerPCs[:]) + for _, pc := range fmtFrames(readerPCs[:n]...) { + fmt.Printf("\t%s\n", pc) + } + + // We already printed a stack trace for the reader, so now we can + // simply exit. Printing a second one with panic or base.Fatalf + // would just be noise. + os.Exit(1) } func (r *decoder) bool() bool { @@ -154,16 +220,12 @@ func (r *decoder) bool() bool { func (r *decoder) int64() int64 { r.sync(syncInt64) - x, err := binary.ReadVarint(&r.data) - r.checkErr(err) - return x + return r.rawVarint() } func (r *decoder) uint64() uint64 { r.sync(syncUint64) - x, err := binary.ReadUvarint(&r.data) - r.checkErr(err) - return x + return r.rawUvarint() } func (r *decoder) len() int { x := r.uint64(); v := int(x); assert(uint64(v) == x); return v } @@ -177,11 +239,7 @@ func (r *decoder) code(mark syncMarker) int { func (r *decoder) reloc(k reloc) int { r.sync(syncUseReloc) - idx := r.len() - - e := r.relocs[idx] - assert(e.kind == k) - return e.idx + return r.rawReloc(k, r.len()) } func (r *decoder) string() string { |