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Diffstat (limited to '')
| -rw-r--r-- | src/runtime/pprof/proto.go | 762 |
1 files changed, 762 insertions, 0 deletions
diff --git a/src/runtime/pprof/proto.go b/src/runtime/pprof/proto.go new file mode 100644 index 0000000..5214374 --- /dev/null +++ b/src/runtime/pprof/proto.go @@ -0,0 +1,762 @@ +// Copyright 2016 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 pprof + +import ( + "bytes" + "compress/gzip" + "fmt" + "internal/abi" + "io" + "runtime" + "strconv" + "strings" + "time" + "unsafe" +) + +// lostProfileEvent is the function to which lost profiling +// events are attributed. +// (The name shows up in the pprof graphs.) +func lostProfileEvent() { lostProfileEvent() } + +// A profileBuilder writes a profile incrementally from a +// stream of profile samples delivered by the runtime. +type profileBuilder struct { + start time.Time + end time.Time + havePeriod bool + period int64 + m profMap + + // encoding state + w io.Writer + zw *gzip.Writer + pb protobuf + strings []string + stringMap map[string]int + locs map[uintptr]locInfo // list of locInfo starting with the given PC. + funcs map[string]int // Package path-qualified function name to Function.ID + mem []memMap + deck pcDeck +} + +type memMap struct { + // initialized as reading mapping + start uintptr // Address at which the binary (or DLL) is loaded into memory. + end uintptr // The limit of the address range occupied by this mapping. + offset uint64 // Offset in the binary that corresponds to the first mapped address. + file string // The object this entry is loaded from. + buildID string // A string that uniquely identifies a particular program version with high probability. + + funcs symbolizeFlag + fake bool // map entry was faked; /proc/self/maps wasn't available +} + +// symbolizeFlag keeps track of symbolization result. +// +// 0 : no symbol lookup was performed +// 1<<0 (lookupTried) : symbol lookup was performed +// 1<<1 (lookupFailed): symbol lookup was performed but failed +type symbolizeFlag uint8 + +const ( + lookupTried symbolizeFlag = 1 << iota + lookupFailed symbolizeFlag = 1 << iota +) + +const ( + // message Profile + tagProfile_SampleType = 1 // repeated ValueType + tagProfile_Sample = 2 // repeated Sample + tagProfile_Mapping = 3 // repeated Mapping + tagProfile_Location = 4 // repeated Location + tagProfile_Function = 5 // repeated Function + tagProfile_StringTable = 6 // repeated string + tagProfile_DropFrames = 7 // int64 (string table index) + tagProfile_KeepFrames = 8 // int64 (string table index) + tagProfile_TimeNanos = 9 // int64 + tagProfile_DurationNanos = 10 // int64 + tagProfile_PeriodType = 11 // ValueType (really optional string???) + tagProfile_Period = 12 // int64 + tagProfile_Comment = 13 // repeated int64 + tagProfile_DefaultSampleType = 14 // int64 + + // message ValueType + tagValueType_Type = 1 // int64 (string table index) + tagValueType_Unit = 2 // int64 (string table index) + + // message Sample + tagSample_Location = 1 // repeated uint64 + tagSample_Value = 2 // repeated int64 + tagSample_Label = 3 // repeated Label + + // message Label + tagLabel_Key = 1 // int64 (string table index) + tagLabel_Str = 2 // int64 (string table index) + tagLabel_Num = 3 // int64 + + // message Mapping + tagMapping_ID = 1 // uint64 + tagMapping_Start = 2 // uint64 + tagMapping_Limit = 3 // uint64 + tagMapping_Offset = 4 // uint64 + tagMapping_Filename = 5 // int64 (string table index) + tagMapping_BuildID = 6 // int64 (string table index) + tagMapping_HasFunctions = 7 // bool + tagMapping_HasFilenames = 8 // bool + tagMapping_HasLineNumbers = 9 // bool + tagMapping_HasInlineFrames = 10 // bool + + // message Location + tagLocation_ID = 1 // uint64 + tagLocation_MappingID = 2 // uint64 + tagLocation_Address = 3 // uint64 + tagLocation_Line = 4 // repeated Line + + // message Line + tagLine_FunctionID = 1 // uint64 + tagLine_Line = 2 // int64 + + // message Function + tagFunction_ID = 1 // uint64 + tagFunction_Name = 2 // int64 (string table index) + tagFunction_SystemName = 3 // int64 (string table index) + tagFunction_Filename = 4 // int64 (string table index) + tagFunction_StartLine = 5 // int64 +) + +// stringIndex adds s to the string table if not already present +// and returns the index of s in the string table. +func (b *profileBuilder) stringIndex(s string) int64 { + id, ok := b.stringMap[s] + if !ok { + id = len(b.strings) + b.strings = append(b.strings, s) + b.stringMap[s] = id + } + return int64(id) +} + +func (b *profileBuilder) flush() { + const dataFlush = 4096 + if b.pb.nest == 0 && len(b.pb.data) > dataFlush { + b.zw.Write(b.pb.data) + b.pb.data = b.pb.data[:0] + } +} + +// pbValueType encodes a ValueType message to b.pb. +func (b *profileBuilder) pbValueType(tag int, typ, unit string) { + start := b.pb.startMessage() + b.pb.int64(tagValueType_Type, b.stringIndex(typ)) + b.pb.int64(tagValueType_Unit, b.stringIndex(unit)) + b.pb.endMessage(tag, start) +} + +// pbSample encodes a Sample message to b.pb. +func (b *profileBuilder) pbSample(values []int64, locs []uint64, labels func()) { + start := b.pb.startMessage() + b.pb.int64s(tagSample_Value, values) + b.pb.uint64s(tagSample_Location, locs) + if labels != nil { + labels() + } + b.pb.endMessage(tagProfile_Sample, start) + b.flush() +} + +// pbLabel encodes a Label message to b.pb. +func (b *profileBuilder) pbLabel(tag int, key, str string, num int64) { + start := b.pb.startMessage() + b.pb.int64Opt(tagLabel_Key, b.stringIndex(key)) + b.pb.int64Opt(tagLabel_Str, b.stringIndex(str)) + b.pb.int64Opt(tagLabel_Num, num) + b.pb.endMessage(tag, start) +} + +// pbLine encodes a Line message to b.pb. +func (b *profileBuilder) pbLine(tag int, funcID uint64, line int64) { + start := b.pb.startMessage() + b.pb.uint64Opt(tagLine_FunctionID, funcID) + b.pb.int64Opt(tagLine_Line, line) + b.pb.endMessage(tag, start) +} + +// pbMapping encodes a Mapping message to b.pb. +func (b *profileBuilder) pbMapping(tag int, id, base, limit, offset uint64, file, buildID string, hasFuncs bool) { + start := b.pb.startMessage() + b.pb.uint64Opt(tagMapping_ID, id) + b.pb.uint64Opt(tagMapping_Start, base) + b.pb.uint64Opt(tagMapping_Limit, limit) + b.pb.uint64Opt(tagMapping_Offset, offset) + b.pb.int64Opt(tagMapping_Filename, b.stringIndex(file)) + b.pb.int64Opt(tagMapping_BuildID, b.stringIndex(buildID)) + // TODO: we set HasFunctions if all symbols from samples were symbolized (hasFuncs). + // Decide what to do about HasInlineFrames and HasLineNumbers. + // Also, another approach to handle the mapping entry with + // incomplete symbolization results is to duplicate the mapping + // entry (but with different Has* fields values) and use + // different entries for symbolized locations and unsymbolized locations. + if hasFuncs { + b.pb.bool(tagMapping_HasFunctions, true) + } + b.pb.endMessage(tag, start) +} + +func allFrames(addr uintptr) ([]runtime.Frame, symbolizeFlag) { + // Expand this one address using CallersFrames so we can cache + // each expansion. In general, CallersFrames takes a whole + // stack, but in this case we know there will be no skips in + // the stack and we have return PCs anyway. + frames := runtime.CallersFrames([]uintptr{addr}) + frame, more := frames.Next() + if frame.Function == "runtime.goexit" { + // Short-circuit if we see runtime.goexit so the loop + // below doesn't allocate a useless empty location. + return nil, 0 + } + + symbolizeResult := lookupTried + if frame.PC == 0 || frame.Function == "" || frame.File == "" || frame.Line == 0 { + symbolizeResult |= lookupFailed + } + + if frame.PC == 0 { + // If we failed to resolve the frame, at least make up + // a reasonable call PC. This mostly happens in tests. + frame.PC = addr - 1 + } + ret := []runtime.Frame{frame} + for frame.Function != "runtime.goexit" && more { + frame, more = frames.Next() + ret = append(ret, frame) + } + return ret, symbolizeResult +} + +type locInfo struct { + // location id assigned by the profileBuilder + id uint64 + + // sequence of PCs, including the fake PCs returned by the traceback + // to represent inlined functions + // https://github.com/golang/go/blob/d6f2f833c93a41ec1c68e49804b8387a06b131c5/src/runtime/traceback.go#L347-L368 + pcs []uintptr + + // firstPCFrames and firstPCSymbolizeResult hold the results of the + // allFrames call for the first (leaf-most) PC this locInfo represents + firstPCFrames []runtime.Frame + firstPCSymbolizeResult symbolizeFlag +} + +// newProfileBuilder returns a new profileBuilder. +// CPU profiling data obtained from the runtime can be added +// by calling b.addCPUData, and then the eventual profile +// can be obtained by calling b.finish. +func newProfileBuilder(w io.Writer) *profileBuilder { + zw, _ := gzip.NewWriterLevel(w, gzip.BestSpeed) + b := &profileBuilder{ + w: w, + zw: zw, + start: time.Now(), + strings: []string{""}, + stringMap: map[string]int{"": 0}, + locs: map[uintptr]locInfo{}, + funcs: map[string]int{}, + } + b.readMapping() + return b +} + +// addCPUData adds the CPU profiling data to the profile. +// +// The data must be a whole number of records, as delivered by the runtime. +// len(tags) must be equal to the number of records in data. +func (b *profileBuilder) addCPUData(data []uint64, tags []unsafe.Pointer) error { + if !b.havePeriod { + // first record is period + if len(data) < 3 { + return fmt.Errorf("truncated profile") + } + if data[0] != 3 || data[2] == 0 { + return fmt.Errorf("malformed profile") + } + // data[2] is sampling rate in Hz. Convert to sampling + // period in nanoseconds. + b.period = 1e9 / int64(data[2]) + b.havePeriod = true + data = data[3:] + // Consume tag slot. Note that there isn't a meaningful tag + // value for this record. + tags = tags[1:] + } + + // Parse CPU samples from the profile. + // Each sample is 3+n uint64s: + // data[0] = 3+n + // data[1] = time stamp (ignored) + // data[2] = count + // data[3:3+n] = stack + // If the count is 0 and the stack has length 1, + // that's an overflow record inserted by the runtime + // to indicate that stack[0] samples were lost. + // Otherwise the count is usually 1, + // but in a few special cases like lost non-Go samples + // there can be larger counts. + // Because many samples with the same stack arrive, + // we want to deduplicate immediately, which we do + // using the b.m profMap. + for len(data) > 0 { + if len(data) < 3 || data[0] > uint64(len(data)) { + return fmt.Errorf("truncated profile") + } + if data[0] < 3 || tags != nil && len(tags) < 1 { + return fmt.Errorf("malformed profile") + } + if len(tags) < 1 { + return fmt.Errorf("mismatched profile records and tags") + } + count := data[2] + stk := data[3:data[0]] + data = data[data[0]:] + tag := tags[0] + tags = tags[1:] + + if count == 0 && len(stk) == 1 { + // overflow record + count = uint64(stk[0]) + stk = []uint64{ + // gentraceback guarantees that PCs in the + // stack can be unconditionally decremented and + // still be valid, so we must do the same. + uint64(abi.FuncPCABIInternal(lostProfileEvent) + 1), + } + } + b.m.lookup(stk, tag).count += int64(count) + } + + if len(tags) != 0 { + return fmt.Errorf("mismatched profile records and tags") + } + return nil +} + +// build completes and returns the constructed profile. +func (b *profileBuilder) build() { + b.end = time.Now() + + b.pb.int64Opt(tagProfile_TimeNanos, b.start.UnixNano()) + if b.havePeriod { // must be CPU profile + b.pbValueType(tagProfile_SampleType, "samples", "count") + b.pbValueType(tagProfile_SampleType, "cpu", "nanoseconds") + b.pb.int64Opt(tagProfile_DurationNanos, b.end.Sub(b.start).Nanoseconds()) + b.pbValueType(tagProfile_PeriodType, "cpu", "nanoseconds") + b.pb.int64Opt(tagProfile_Period, b.period) + } + + values := []int64{0, 0} + var locs []uint64 + + for e := b.m.all; e != nil; e = e.nextAll { + values[0] = e.count + values[1] = e.count * b.period + + var labels func() + if e.tag != nil { + labels = func() { + for k, v := range *(*labelMap)(e.tag) { + b.pbLabel(tagSample_Label, k, v, 0) + } + } + } + + locs = b.appendLocsForStack(locs[:0], e.stk) + + b.pbSample(values, locs, labels) + } + + for i, m := range b.mem { + hasFunctions := m.funcs == lookupTried // lookupTried but not lookupFailed + b.pbMapping(tagProfile_Mapping, uint64(i+1), uint64(m.start), uint64(m.end), m.offset, m.file, m.buildID, hasFunctions) + } + + // TODO: Anything for tagProfile_DropFrames? + // TODO: Anything for tagProfile_KeepFrames? + + b.pb.strings(tagProfile_StringTable, b.strings) + b.zw.Write(b.pb.data) + b.zw.Close() +} + +// appendLocsForStack appends the location IDs for the given stack trace to the given +// location ID slice, locs. The addresses in the stack are return PCs or 1 + the PC of +// an inline marker as the runtime traceback function returns. +// +// It may return an empty slice even if locs is non-empty, for example if locs consists +// solely of runtime.goexit. We still count these empty stacks in profiles in order to +// get the right cumulative sample count. +// +// It may emit to b.pb, so there must be no message encoding in progress. +func (b *profileBuilder) appendLocsForStack(locs []uint64, stk []uintptr) (newLocs []uint64) { + b.deck.reset() + + // The last frame might be truncated. Recover lost inline frames. + stk = runtime_expandFinalInlineFrame(stk) + + for len(stk) > 0 { + addr := stk[0] + if l, ok := b.locs[addr]; ok { + // When generating code for an inlined function, the compiler adds + // NOP instructions to the outermost function as a placeholder for + // each layer of inlining. When the runtime generates tracebacks for + // stacks that include inlined functions, it uses the addresses of + // those NOPs as "fake" PCs on the stack as if they were regular + // function call sites. But if a profiling signal arrives while the + // CPU is executing one of those NOPs, its PC will show up as a leaf + // in the profile with its own Location entry. So, always check + // whether addr is a "fake" PC in the context of the current call + // stack by trying to add it to the inlining deck before assuming + // that the deck is complete. + if len(b.deck.pcs) > 0 { + if added := b.deck.tryAdd(addr, l.firstPCFrames, l.firstPCSymbolizeResult); added { + stk = stk[1:] + continue + } + } + + // first record the location if there is any pending accumulated info. + if id := b.emitLocation(); id > 0 { + locs = append(locs, id) + } + + // then, record the cached location. + locs = append(locs, l.id) + + // Skip the matching pcs. + // + // Even if stk was truncated due to the stack depth + // limit, expandFinalInlineFrame above has already + // fixed the truncation, ensuring it is long enough. + stk = stk[len(l.pcs):] + continue + } + + frames, symbolizeResult := allFrames(addr) + if len(frames) == 0 { // runtime.goexit. + if id := b.emitLocation(); id > 0 { + locs = append(locs, id) + } + stk = stk[1:] + continue + } + + if added := b.deck.tryAdd(addr, frames, symbolizeResult); added { + stk = stk[1:] + continue + } + // add failed because this addr is not inlined with the + // existing PCs in the deck. Flush the deck and retry handling + // this pc. + if id := b.emitLocation(); id > 0 { + locs = append(locs, id) + } + + // check cache again - previous emitLocation added a new entry + if l, ok := b.locs[addr]; ok { + locs = append(locs, l.id) + stk = stk[len(l.pcs):] // skip the matching pcs. + } else { + b.deck.tryAdd(addr, frames, symbolizeResult) // must succeed. + stk = stk[1:] + } + } + if id := b.emitLocation(); id > 0 { // emit remaining location. + locs = append(locs, id) + } + return locs +} + +// Here's an example of how Go 1.17 writes out inlined functions, compiled for +// linux/amd64. The disassembly of main.main shows two levels of inlining: main +// calls b, b calls a, a does some work. +// +// inline.go:9 0x4553ec 90 NOPL // func main() { b(v) } +// inline.go:6 0x4553ed 90 NOPL // func b(v *int) { a(v) } +// inline.go:5 0x4553ee 48c7002a000000 MOVQ $0x2a, 0(AX) // func a(v *int) { *v = 42 } +// +// If a profiling signal arrives while executing the MOVQ at 0x4553ee (for line +// 5), the runtime will report the stack as the MOVQ frame being called by the +// NOPL at 0x4553ed (for line 6) being called by the NOPL at 0x4553ec (for line +// 9). +// +// The role of pcDeck is to collapse those three frames back into a single +// location at 0x4553ee, with file/line/function symbolization info representing +// the three layers of calls. It does that via sequential calls to pcDeck.tryAdd +// starting with the leaf-most address. The fourth call to pcDeck.tryAdd will be +// for the caller of main.main. Because main.main was not inlined in its caller, +// the deck will reject the addition, and the fourth PC on the stack will get +// its own location. + +// pcDeck is a helper to detect a sequence of inlined functions from +// a stack trace returned by the runtime. +// +// The stack traces returned by runtime's trackback functions are fully +// expanded (at least for Go functions) and include the fake pcs representing +// inlined functions. The profile proto expects the inlined functions to be +// encoded in one Location message. +// https://github.com/google/pprof/blob/5e965273ee43930341d897407202dd5e10e952cb/proto/profile.proto#L177-L184 +// +// Runtime does not directly expose whether a frame is for an inlined function +// and looking up debug info is not ideal, so we use a heuristic to filter +// the fake pcs and restore the inlined and entry functions. Inlined functions +// have the following properties: +// +// Frame's Func is nil (note: also true for non-Go functions), and +// Frame's Entry matches its entry function frame's Entry (note: could also be true for recursive calls and non-Go functions), and +// Frame's Name does not match its entry function frame's name (note: inlined functions cannot be directly recursive). +// +// As reading and processing the pcs in a stack trace one by one (from leaf to the root), +// we use pcDeck to temporarily hold the observed pcs and their expanded frames +// until we observe the entry function frame. +type pcDeck struct { + pcs []uintptr + frames []runtime.Frame + symbolizeResult symbolizeFlag + + // firstPCFrames indicates the number of frames associated with the first + // (leaf-most) PC in the deck + firstPCFrames int + // firstPCSymbolizeResult holds the results of the allFrames call for the + // first (leaf-most) PC in the deck + firstPCSymbolizeResult symbolizeFlag +} + +func (d *pcDeck) reset() { + d.pcs = d.pcs[:0] + d.frames = d.frames[:0] + d.symbolizeResult = 0 + d.firstPCFrames = 0 + d.firstPCSymbolizeResult = 0 +} + +// tryAdd tries to add the pc and Frames expanded from it (most likely one, +// since the stack trace is already fully expanded) and the symbolizeResult +// to the deck. If it fails the caller needs to flush the deck and retry. +func (d *pcDeck) tryAdd(pc uintptr, frames []runtime.Frame, symbolizeResult symbolizeFlag) (success bool) { + if existing := len(d.frames); existing > 0 { + // 'd.frames' are all expanded from one 'pc' and represent all + // inlined functions so we check only the last one. + newFrame := frames[0] + last := d.frames[existing-1] + if last.Func != nil { // the last frame can't be inlined. Flush. + return false + } + if last.Entry == 0 || newFrame.Entry == 0 { // Possibly not a Go function. Don't try to merge. + return false + } + + if last.Entry != newFrame.Entry { // newFrame is for a different function. + return false + } + if runtime_FrameSymbolName(&last) == runtime_FrameSymbolName(&newFrame) { // maybe recursion. + return false + } + } + d.pcs = append(d.pcs, pc) + d.frames = append(d.frames, frames...) + d.symbolizeResult |= symbolizeResult + if len(d.pcs) == 1 { + d.firstPCFrames = len(d.frames) + d.firstPCSymbolizeResult = symbolizeResult + } + return true +} + +// emitLocation emits the new location and function information recorded in the deck +// and returns the location ID encoded in the profile protobuf. +// It emits to b.pb, so there must be no message encoding in progress. +// It resets the deck. +func (b *profileBuilder) emitLocation() uint64 { + if len(b.deck.pcs) == 0 { + return 0 + } + defer b.deck.reset() + + addr := b.deck.pcs[0] + firstFrame := b.deck.frames[0] + + // We can't write out functions while in the middle of the + // Location message, so record new functions we encounter and + // write them out after the Location. + type newFunc struct { + id uint64 + name, file string + startLine int64 + } + newFuncs := make([]newFunc, 0, 8) + + id := uint64(len(b.locs)) + 1 + b.locs[addr] = locInfo{ + id: id, + pcs: append([]uintptr{}, b.deck.pcs...), + firstPCSymbolizeResult: b.deck.firstPCSymbolizeResult, + firstPCFrames: append([]runtime.Frame{}, b.deck.frames[:b.deck.firstPCFrames]...), + } + + start := b.pb.startMessage() + b.pb.uint64Opt(tagLocation_ID, id) + b.pb.uint64Opt(tagLocation_Address, uint64(firstFrame.PC)) + for _, frame := range b.deck.frames { + // Write out each line in frame expansion. + funcName := runtime_FrameSymbolName(&frame) + funcID := uint64(b.funcs[funcName]) + if funcID == 0 { + funcID = uint64(len(b.funcs)) + 1 + b.funcs[funcName] = int(funcID) + newFuncs = append(newFuncs, newFunc{ + id: funcID, + name: funcName, + file: frame.File, + startLine: int64(runtime_FrameStartLine(&frame)), + }) + } + b.pbLine(tagLocation_Line, funcID, int64(frame.Line)) + } + for i := range b.mem { + if b.mem[i].start <= addr && addr < b.mem[i].end || b.mem[i].fake { + b.pb.uint64Opt(tagLocation_MappingID, uint64(i+1)) + + m := b.mem[i] + m.funcs |= b.deck.symbolizeResult + b.mem[i] = m + break + } + } + b.pb.endMessage(tagProfile_Location, start) + + // Write out functions we found during frame expansion. + for _, fn := range newFuncs { + start := b.pb.startMessage() + b.pb.uint64Opt(tagFunction_ID, fn.id) + b.pb.int64Opt(tagFunction_Name, b.stringIndex(fn.name)) + b.pb.int64Opt(tagFunction_SystemName, b.stringIndex(fn.name)) + b.pb.int64Opt(tagFunction_Filename, b.stringIndex(fn.file)) + b.pb.int64Opt(tagFunction_StartLine, fn.startLine) + b.pb.endMessage(tagProfile_Function, start) + } + + b.flush() + return id +} + +var space = []byte(" ") +var newline = []byte("\n") + +func parseProcSelfMaps(data []byte, addMapping func(lo, hi, offset uint64, file, buildID string)) { + // $ cat /proc/self/maps + // 00400000-0040b000 r-xp 00000000 fc:01 787766 /bin/cat + // 0060a000-0060b000 r--p 0000a000 fc:01 787766 /bin/cat + // 0060b000-0060c000 rw-p 0000b000 fc:01 787766 /bin/cat + // 014ab000-014cc000 rw-p 00000000 00:00 0 [heap] + // 7f7d76af8000-7f7d7797c000 r--p 00000000 fc:01 1318064 /usr/lib/locale/locale-archive + // 7f7d7797c000-7f7d77b36000 r-xp 00000000 fc:01 1180226 /lib/x86_64-linux-gnu/libc-2.19.so + // 7f7d77b36000-7f7d77d36000 ---p 001ba000 fc:01 1180226 /lib/x86_64-linux-gnu/libc-2.19.so + // 7f7d77d36000-7f7d77d3a000 r--p 001ba000 fc:01 1180226 /lib/x86_64-linux-gnu/libc-2.19.so + // 7f7d77d3a000-7f7d77d3c000 rw-p 001be000 fc:01 1180226 /lib/x86_64-linux-gnu/libc-2.19.so + // 7f7d77d3c000-7f7d77d41000 rw-p 00000000 00:00 0 + // 7f7d77d41000-7f7d77d64000 r-xp 00000000 fc:01 1180217 /lib/x86_64-linux-gnu/ld-2.19.so + // 7f7d77f3f000-7f7d77f42000 rw-p 00000000 00:00 0 + // 7f7d77f61000-7f7d77f63000 rw-p 00000000 00:00 0 + // 7f7d77f63000-7f7d77f64000 r--p 00022000 fc:01 1180217 /lib/x86_64-linux-gnu/ld-2.19.so + // 7f7d77f64000-7f7d77f65000 rw-p 00023000 fc:01 1180217 /lib/x86_64-linux-gnu/ld-2.19.so + // 7f7d77f65000-7f7d77f66000 rw-p 00000000 00:00 0 + // 7ffc342a2000-7ffc342c3000 rw-p 00000000 00:00 0 [stack] + // 7ffc34343000-7ffc34345000 r-xp 00000000 00:00 0 [vdso] + // ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0 [vsyscall] + + var line []byte + // next removes and returns the next field in the line. + // It also removes from line any spaces following the field. + next := func() []byte { + var f []byte + f, line, _ = bytes.Cut(line, space) + line = bytes.TrimLeft(line, " ") + return f + } + + for len(data) > 0 { + line, data, _ = bytes.Cut(data, newline) + addr := next() + loStr, hiStr, ok := strings.Cut(string(addr), "-") + if !ok { + continue + } + lo, err := strconv.ParseUint(loStr, 16, 64) + if err != nil { + continue + } + hi, err := strconv.ParseUint(hiStr, 16, 64) + if err != nil { + continue + } + perm := next() + if len(perm) < 4 || perm[2] != 'x' { + // Only interested in executable mappings. + continue + } + offset, err := strconv.ParseUint(string(next()), 16, 64) + if err != nil { + continue + } + next() // dev + inode := next() // inode + if line == nil { + continue + } + file := string(line) + + // Trim deleted file marker. + deletedStr := " (deleted)" + deletedLen := len(deletedStr) + if len(file) >= deletedLen && file[len(file)-deletedLen:] == deletedStr { + file = file[:len(file)-deletedLen] + } + + if len(inode) == 1 && inode[0] == '0' && file == "" { + // Huge-page text mappings list the initial fragment of + // mapped but unpopulated memory as being inode 0. + // Don't report that part. + // But [vdso] and [vsyscall] are inode 0, so let non-empty file names through. + continue + } + + // TODO: pprof's remapMappingIDs makes one adjustment: + // 1. If there is an /anon_hugepage mapping first and it is + // consecutive to a next mapping, drop the /anon_hugepage. + // There's no indication why this is needed. + // Let's try not doing this and see what breaks. + // If we do need it, it would go here, before we + // enter the mappings into b.mem in the first place. + + buildID, _ := elfBuildID(file) + addMapping(lo, hi, offset, file, buildID) + } +} + +func (b *profileBuilder) addMapping(lo, hi, offset uint64, file, buildID string) { + b.addMappingEntry(lo, hi, offset, file, buildID, false) +} + +func (b *profileBuilder) addMappingEntry(lo, hi, offset uint64, file, buildID string, fake bool) { + b.mem = append(b.mem, memMap{ + start: uintptr(lo), + end: uintptr(hi), + offset: offset, + file: file, + buildID: buildID, + fake: fake, + }) +} |