Documentation
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Overview ¶
Package heapsnapshot holds the normalized in-memory model produced by parsing a runtime/debug.WriteHeapDump output.
The model is intentionally agnostic of how it was obtained. Higher-level phases convert it into a process graph or compute per-goroutine reachability. Phase 3 only fills it in.
Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type DataSegment ¶
type DataSegment struct {
Kind string
Addr uint64
Size uint64
Fields []Field
PointerAddrs []uint64
PointerSlots []uint64
}
DataSegment is one `data` or `bss` record.
PointerAddrs and PointerSlots are parallel slices: PointerAddrs[i] is the decoded pointer value and PointerSlots[i] is the virtual address of the slot (Addr + field offset) that holds it. PointerSlots is populated by the parser; consumers must range over PointerAddrs and guard with i < len(PointerSlots) in case a future parser omits it.
type DumpParams ¶
type DumpParams struct {
BigEndian bool
PtrSize int
HeapStart uint64
HeapEnd uint64
GOARCH string
BuildVersion string
NumCPU uint64
}
DumpParams matches the `params` record at the start of every heap dump.
type Field ¶
Field describes a single typed slot inside an object, stack frame, or data/bss segment.
type FieldKind ¶
type FieldKind uint64
FieldKind matches the kind tag used inside the heap dump field lists.
type Finalizer ¶
type Finalizer struct {
ObjectAddr uint64
FuncVal uint64
FuncPC uint64
TypeAddr uint64
PtrTypeAddr uint64
}
Finalizer is one `finalizer` record.
type Goroutine ¶
type Goroutine struct {
Addr uint64
StackTop uint64
ID uint64
GoPC uint64
Status uint64
IsSystem bool
IsBackground bool
WaitSince uint64
WaitReason string
Context uint64
M uint64
Defer uint64
Panic uint64
Frames []StackFrame
}
Goroutine is one goroutine record. Frames are filled in as the parser reads `stack frame` records following the goroutine record.
type HeapSnapshot ¶
type HeapSnapshot struct {
Header string
Params DumpParams
Types map[uint64]TypeInfo
Itabs map[uint64]Itab
Objects []Object
Goroutines []Goroutine
Globals []Root
Data []DataSegment
BSS []DataSegment
Finalizers []Finalizer
QueuedFinalizers []QueuedFinalizer
OSThreads []OSThread
MemStats map[string]uint64
Stats ParseStats
Warnings []string
}
HeapSnapshot is the normalized model of a single heap dump.
type Object ¶
type Object struct {
Addr uint64
Size uint64
// Contents is empty unless Options.KeepObjectContents was set on the
// parser. PointerAddrs already carries every direct pointer that was
// decoded out of contents.
Contents []byte
Fields []Field
PointerAddrs []uint64
}
Object is one heap-allocated object discovered by the runtime.
type ParseStats ¶
type ParseStats struct {
ObjectCount int
ObjectBytes uint64
ObjectPointers int
TypeCount int
ItabCount int
GoroutineCount int
StackFrameCount int
StackPointers int
OtherRootCount int
DataCount int
DataPointers int
BSSCount int
BSSPointers int
GlobalRootCount int
FinalizerCount int
QueuedFinalizers int
OSThreadCount int
DeferCount int
PanicCount int
MemProfCount int
AllocSampleCount int
UnknownRecords int
// Iface/eface fields decoded by the parser. The data word of each
// interface field is emitted as a candidate pointer; the graph resolver
// drops any value that does not map to a known heap object.
// For current Go runtime versions (1.24+) these counts are always zero
// because the dump writer only emits fieldKindPtr from GC bitmaps.
InterfaceFieldsDecoded int
EfaceFieldsDecoded int
}
ParseStats holds counters useful for summary output.
type QueuedFinalizer ¶
type QueuedFinalizer struct {
ObjectAddr uint64
FuncVal uint64
FuncPC uint64
TypeAddr uint64
PtrTypeAddr uint64
}
QueuedFinalizer is one `queued finalizer` record. The runtime emits the same fields as Finalizer but the meaning is "already queued for run".
type Root ¶
Root represents a single root pointer attribution. The address is the slot that holds the pointer; PointerAddr is the decoded pointer value.
type StackFrame ¶
type StackFrame struct {
SP uint64
Depth uint64
ChildSP uint64
EntryPC uint64
CurrentPC uint64
ContinuePC uint64
FuncName string
Size uint64
Fields []Field
PointerAddrs []uint64
PointerSlots []uint64
}
StackFrame is one frame within a goroutine's stack.
PointerAddrs holds the decoded pointer values; PointerSlots holds the stack slot address (SP + field offset) where each pointer was read. The two slices are parallel and have equal length when the parser recorded slot addresses; consumers should range over PointerAddrs and only read PointerSlots[i] if i is in bounds, in case a future parser stops emitting slots for some frames.
Source Files