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runtime: consolidate stkframe and its methods into stkframe.go
The stkframe struct and its methods are strewn across different source files. Since they actually have a pretty coherent theme at this point, migrate it all into a new file, stkframe.go. There are no code changes in this CL. For #54466, albeit rather indirectly. Change-Id: Ibe53fc4b1106d131005e1c9d491be838a8f14211 Reviewed-on: https://go-review.googlesource.com/c/go/+/424516 Reviewed-by: Michael Pratt <mpratt@google.com> Reviewed-by: Cherry Mui <cherryyz@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> Run-TryBot: Austin Clements <austin@google.com> Auto-Submit: Austin Clements <austin@google.com>
This commit is contained in:
Austin Clements
Gopher Robot
parent
b91e373729
commit
35026f3732
@ -985,55 +985,6 @@ type _panic struct {
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goexit bool
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}
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// A stkframe holds information about a single physical stack frame.
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type stkframe struct {
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// fn is the function being run in this frame. If there is
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// inlining, this is the outermost function.
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fn funcInfo
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// pc is the program counter within fn.
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//
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// The meaning of this is subtle:
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//
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// - Typically, this frame performed a regular function call
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// and this is the return PC (just after the CALL
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// instruction). In this case, pc-1 reflects the CALL
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// instruction itself and is the correct source of symbolic
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// information.
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//
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// - If this frame "called" sigpanic, then pc is the
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// instruction that panicked, and pc is the correct address
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// to use for symbolic information.
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//
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// - If this is the innermost frame, then PC is where
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// execution will continue, but it may not be the
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// instruction following a CALL. This may be from
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// cooperative preemption, in which case this is the
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// instruction after the call to morestack. Or this may be
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// from a signal or an un-started goroutine, in which case
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// PC could be any instruction, including the first
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// instruction in a function. Conventionally, we use pc-1
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// for symbolic information, unless pc == fn.entry(), in
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// which case we use pc.
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pc uintptr
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// continpc is the PC where execution will continue in fn, or
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// 0 if execution will not continue in this frame.
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//
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// This is usually the same as pc, unless this frame "called"
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// sigpanic, in which case it's either the address of
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// deferreturn or 0 if this frame will never execute again.
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//
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// This is the PC to use to look up GC liveness for this frame.
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continpc uintptr
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lr uintptr // program counter at caller aka link register
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sp uintptr // stack pointer at pc
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fp uintptr // stack pointer at caller aka frame pointer
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varp uintptr // top of local variables
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argp uintptr // pointer to function arguments
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}
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// ancestorInfo records details of where a goroutine was started.
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type ancestorInfo struct {
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pcs []uintptr // pcs from the stack of this goroutine
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@ -1247,142 +1247,6 @@ func freeStackSpans() {
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unlock(&stackLarge.lock)
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}
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// getStackMap returns the locals and arguments live pointer maps, and
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// stack object list for frame.
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func (frame *stkframe) getStackMap(cache *pcvalueCache, debug bool) (locals, args bitvector, objs []stackObjectRecord) {
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targetpc := frame.continpc
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if targetpc == 0 {
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// Frame is dead. Return empty bitvectors.
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return
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}
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f := frame.fn
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pcdata := int32(-1)
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if targetpc != f.entry() {
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// Back up to the CALL. If we're at the function entry
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// point, we want to use the entry map (-1), even if
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// the first instruction of the function changes the
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// stack map.
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targetpc--
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pcdata = pcdatavalue(f, _PCDATA_StackMapIndex, targetpc, cache)
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}
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if pcdata == -1 {
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// We do not have a valid pcdata value but there might be a
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// stackmap for this function. It is likely that we are looking
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// at the function prologue, assume so and hope for the best.
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pcdata = 0
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}
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// Local variables.
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size := frame.varp - frame.sp
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var minsize uintptr
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switch goarch.ArchFamily {
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case goarch.ARM64:
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minsize = sys.StackAlign
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default:
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minsize = sys.MinFrameSize
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}
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if size > minsize {
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stackid := pcdata
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stkmap := (*stackmap)(funcdata(f, _FUNCDATA_LocalsPointerMaps))
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if stkmap == nil || stkmap.n <= 0 {
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print("runtime: frame ", funcname(f), " untyped locals ", hex(frame.varp-size), "+", hex(size), "\n")
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throw("missing stackmap")
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}
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// If nbit == 0, there's no work to do.
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if stkmap.nbit > 0 {
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if stackid < 0 || stackid >= stkmap.n {
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// don't know where we are
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print("runtime: pcdata is ", stackid, " and ", stkmap.n, " locals stack map entries for ", funcname(f), " (targetpc=", hex(targetpc), ")\n")
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throw("bad symbol table")
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}
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locals = stackmapdata(stkmap, stackid)
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if stackDebug >= 3 && debug {
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print(" locals ", stackid, "/", stkmap.n, " ", locals.n, " words ", locals.bytedata, "\n")
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}
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} else if stackDebug >= 3 && debug {
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print(" no locals to adjust\n")
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}
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}
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// Arguments. First fetch frame size and special-case argument maps.
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var isReflect bool
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args, isReflect = frame.argMapInternal()
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if args.n > 0 && args.bytedata == nil {
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// Non-empty argument frame, but not a special map.
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// Fetch the argument map at pcdata.
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stackmap := (*stackmap)(funcdata(f, _FUNCDATA_ArgsPointerMaps))
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if stackmap == nil || stackmap.n <= 0 {
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print("runtime: frame ", funcname(f), " untyped args ", hex(frame.argp), "+", hex(args.n*goarch.PtrSize), "\n")
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throw("missing stackmap")
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}
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if pcdata < 0 || pcdata >= stackmap.n {
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// don't know where we are
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print("runtime: pcdata is ", pcdata, " and ", stackmap.n, " args stack map entries for ", funcname(f), " (targetpc=", hex(targetpc), ")\n")
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throw("bad symbol table")
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}
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if stackmap.nbit == 0 {
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args.n = 0
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} else {
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args = stackmapdata(stackmap, pcdata)
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}
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}
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// stack objects.
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if (GOARCH == "amd64" || GOARCH == "arm64" || GOARCH == "ppc64" || GOARCH == "ppc64le" || GOARCH == "riscv64") &&
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unsafe.Sizeof(abi.RegArgs{}) > 0 && isReflect {
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// For reflect.makeFuncStub and reflect.methodValueCall,
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// we need to fake the stack object record.
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// These frames contain an internal/abi.RegArgs at a hard-coded offset.
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// This offset matches the assembly code on amd64 and arm64.
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objs = methodValueCallFrameObjs[:]
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} else {
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p := funcdata(f, _FUNCDATA_StackObjects)
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if p != nil {
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n := *(*uintptr)(p)
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p = add(p, goarch.PtrSize)
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r0 := (*stackObjectRecord)(noescape(p))
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objs = unsafe.Slice(r0, int(n))
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// Note: the noescape above is needed to keep
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// getStackMap from "leaking param content:
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// frame". That leak propagates up to getgcmask, then
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// GCMask, then verifyGCInfo, which converts the stack
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// gcinfo tests into heap gcinfo tests :(
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}
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}
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return
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}
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var methodValueCallFrameObjs [1]stackObjectRecord // initialized in stackobjectinit
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func stkobjinit() {
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var abiRegArgsEface any = abi.RegArgs{}
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abiRegArgsType := efaceOf(&abiRegArgsEface)._type
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if abiRegArgsType.kind&kindGCProg != 0 {
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throw("abiRegArgsType needs GC Prog, update methodValueCallFrameObjs")
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}
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// Set methodValueCallFrameObjs[0].gcdataoff so that
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// stackObjectRecord.gcdata() will work correctly with it.
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ptr := uintptr(unsafe.Pointer(&methodValueCallFrameObjs[0]))
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var mod *moduledata
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for datap := &firstmoduledata; datap != nil; datap = datap.next {
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if datap.gofunc <= ptr && ptr < datap.end {
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mod = datap
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break
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}
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}
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if mod == nil {
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throw("methodValueCallFrameObjs is not in a module")
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}
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methodValueCallFrameObjs[0] = stackObjectRecord{
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off: -int32(alignUp(abiRegArgsType.size, 8)), // It's always the highest address local.
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size: int32(abiRegArgsType.size),
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_ptrdata: int32(abiRegArgsType.ptrdata),
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gcdataoff: uint32(uintptr(unsafe.Pointer(abiRegArgsType.gcdata)) - mod.rodata),
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}
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}
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// A stackObjectRecord is generated by the compiler for each stack object in a stack frame.
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// This record must match the generator code in cmd/compile/internal/liveness/plive.go:emitStackObjects.
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type stackObjectRecord struct {
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288
src/runtime/stkframe.go
Normal file
288
src/runtime/stkframe.go
Normal file
@ -0,0 +1,288 @@
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// Copyright 2022 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package runtime
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import (
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"internal/abi"
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"internal/goarch"
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"runtime/internal/sys"
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"unsafe"
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)
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// A stkframe holds information about a single physical stack frame.
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type stkframe struct {
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// fn is the function being run in this frame. If there is
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// inlining, this is the outermost function.
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fn funcInfo
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// pc is the program counter within fn.
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//
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// The meaning of this is subtle:
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//
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// - Typically, this frame performed a regular function call
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// and this is the return PC (just after the CALL
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// instruction). In this case, pc-1 reflects the CALL
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// instruction itself and is the correct source of symbolic
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// information.
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//
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// - If this frame "called" sigpanic, then pc is the
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// instruction that panicked, and pc is the correct address
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// to use for symbolic information.
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//
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// - If this is the innermost frame, then PC is where
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// execution will continue, but it may not be the
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// instruction following a CALL. This may be from
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// cooperative preemption, in which case this is the
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// instruction after the call to morestack. Or this may be
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// from a signal or an un-started goroutine, in which case
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// PC could be any instruction, including the first
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// instruction in a function. Conventionally, we use pc-1
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// for symbolic information, unless pc == fn.entry(), in
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// which case we use pc.
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pc uintptr
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// continpc is the PC where execution will continue in fn, or
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// 0 if execution will not continue in this frame.
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//
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// This is usually the same as pc, unless this frame "called"
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// sigpanic, in which case it's either the address of
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// deferreturn or 0 if this frame will never execute again.
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//
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// This is the PC to use to look up GC liveness for this frame.
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continpc uintptr
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lr uintptr // program counter at caller aka link register
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sp uintptr // stack pointer at pc
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fp uintptr // stack pointer at caller aka frame pointer
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varp uintptr // top of local variables
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argp uintptr // pointer to function arguments
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}
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// reflectMethodValue is a partial duplicate of reflect.makeFuncImpl
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// and reflect.methodValue.
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type reflectMethodValue struct {
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fn uintptr
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stack *bitvector // ptrmap for both args and results
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argLen uintptr // just args
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}
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// argBytes returns the argument frame size for a call to frame.fn.
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func (frame *stkframe) argBytes() uintptr {
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if frame.fn.args != _ArgsSizeUnknown {
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return uintptr(frame.fn.args)
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}
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// This is an uncommon and complicated case. Fall back to fully
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// fetching the argument map to compute its size.
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argMap, _ := frame.argMapInternal()
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return uintptr(argMap.n) * goarch.PtrSize
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}
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// argMapInternal is used internally by stkframe to fetch special
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// argument maps.
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//
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// argMap.n is always populated with the size of the argument map.
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//
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// argMap.bytedata is only populated for dynamic argument maps (used
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// by reflect). If the caller requires the argument map, it should use
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// this if non-nil, and otherwise fetch the argument map using the
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// current PC.
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//
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// hasReflectStackObj indicates that this frame also has a reflect
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// function stack object, which the caller must synthesize.
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func (frame *stkframe) argMapInternal() (argMap bitvector, hasReflectStackObj bool) {
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f := frame.fn
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argMap.n = f.args / goarch.PtrSize
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if f.args == _ArgsSizeUnknown {
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// Extract argument bitmaps for reflect stubs from the calls they made to reflect.
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switch funcname(f) {
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case "reflect.makeFuncStub", "reflect.methodValueCall":
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// These take a *reflect.methodValue as their
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// context register and immediately save it to 0(SP).
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// Get the methodValue from 0(SP).
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arg0 := frame.sp + sys.MinFrameSize
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minSP := frame.fp
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if !usesLR {
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// The CALL itself pushes a word.
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// Undo that adjustment.
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minSP -= goarch.PtrSize
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}
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if arg0 >= minSP {
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// The function hasn't started yet.
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// This only happens if f was the
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// start function of a new goroutine
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// that hasn't run yet *and* f takes
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// no arguments and has no results
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// (otherwise it will get wrapped in a
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// closure). In this case, we can't
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// reach into its locals because it
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// doesn't have locals yet, but we
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// also know its argument map is
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// empty.
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if frame.pc != f.entry() {
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print("runtime: confused by ", funcname(f), ": no frame (sp=", hex(frame.sp), " fp=", hex(frame.fp), ") at entry+", hex(frame.pc-f.entry()), "\n")
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throw("reflect mismatch")
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}
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return bitvector{}, false // No locals, so also no stack objects
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}
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hasReflectStackObj = true
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mv := *(**reflectMethodValue)(unsafe.Pointer(arg0))
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// Figure out whether the return values are valid.
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// Reflect will update this value after it copies
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// in the return values.
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retValid := *(*bool)(unsafe.Pointer(arg0 + 4*goarch.PtrSize))
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if mv.fn != f.entry() {
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print("runtime: confused by ", funcname(f), "\n")
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throw("reflect mismatch")
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}
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argMap = *mv.stack
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if !retValid {
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// argMap.n includes the results, but
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// those aren't valid, so drop them.
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n := int32((uintptr(mv.argLen) &^ (goarch.PtrSize - 1)) / goarch.PtrSize)
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if n < argMap.n {
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argMap.n = n
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}
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}
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}
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}
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return
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}
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// getStackMap returns the locals and arguments live pointer maps, and
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// stack object list for frame.
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func (frame *stkframe) getStackMap(cache *pcvalueCache, debug bool) (locals, args bitvector, objs []stackObjectRecord) {
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targetpc := frame.continpc
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if targetpc == 0 {
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// Frame is dead. Return empty bitvectors.
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return
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}
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f := frame.fn
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pcdata := int32(-1)
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if targetpc != f.entry() {
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// Back up to the CALL. If we're at the function entry
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// point, we want to use the entry map (-1), even if
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// the first instruction of the function changes the
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// stack map.
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targetpc--
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pcdata = pcdatavalue(f, _PCDATA_StackMapIndex, targetpc, cache)
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}
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if pcdata == -1 {
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// We do not have a valid pcdata value but there might be a
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// stackmap for this function. It is likely that we are looking
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// at the function prologue, assume so and hope for the best.
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pcdata = 0
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}
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// Local variables.
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size := frame.varp - frame.sp
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var minsize uintptr
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switch goarch.ArchFamily {
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case goarch.ARM64:
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minsize = sys.StackAlign
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default:
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minsize = sys.MinFrameSize
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}
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if size > minsize {
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stackid := pcdata
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stkmap := (*stackmap)(funcdata(f, _FUNCDATA_LocalsPointerMaps))
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if stkmap == nil || stkmap.n <= 0 {
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print("runtime: frame ", funcname(f), " untyped locals ", hex(frame.varp-size), "+", hex(size), "\n")
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throw("missing stackmap")
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}
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// If nbit == 0, there's no work to do.
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if stkmap.nbit > 0 {
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if stackid < 0 || stackid >= stkmap.n {
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// don't know where we are
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print("runtime: pcdata is ", stackid, " and ", stkmap.n, " locals stack map entries for ", funcname(f), " (targetpc=", hex(targetpc), ")\n")
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throw("bad symbol table")
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}
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locals = stackmapdata(stkmap, stackid)
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if stackDebug >= 3 && debug {
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print(" locals ", stackid, "/", stkmap.n, " ", locals.n, " words ", locals.bytedata, "\n")
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}
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} else if stackDebug >= 3 && debug {
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print(" no locals to adjust\n")
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}
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}
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// Arguments. First fetch frame size and special-case argument maps.
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var isReflect bool
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args, isReflect = frame.argMapInternal()
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if args.n > 0 && args.bytedata == nil {
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// Non-empty argument frame, but not a special map.
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// Fetch the argument map at pcdata.
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stackmap := (*stackmap)(funcdata(f, _FUNCDATA_ArgsPointerMaps))
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if stackmap == nil || stackmap.n <= 0 {
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print("runtime: frame ", funcname(f), " untyped args ", hex(frame.argp), "+", hex(args.n*goarch.PtrSize), "\n")
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throw("missing stackmap")
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}
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if pcdata < 0 || pcdata >= stackmap.n {
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// don't know where we are
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print("runtime: pcdata is ", pcdata, " and ", stackmap.n, " args stack map entries for ", funcname(f), " (targetpc=", hex(targetpc), ")\n")
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throw("bad symbol table")
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}
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if stackmap.nbit == 0 {
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args.n = 0
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} else {
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args = stackmapdata(stackmap, pcdata)
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||||
}
|
||||
}
|
||||
|
||||
// stack objects.
|
||||
if (GOARCH == "amd64" || GOARCH == "arm64" || GOARCH == "ppc64" || GOARCH == "ppc64le" || GOARCH == "riscv64") &&
|
||||
unsafe.Sizeof(abi.RegArgs{}) > 0 && isReflect {
|
||||
// For reflect.makeFuncStub and reflect.methodValueCall,
|
||||
// we need to fake the stack object record.
|
||||
// These frames contain an internal/abi.RegArgs at a hard-coded offset.
|
||||
// This offset matches the assembly code on amd64 and arm64.
|
||||
objs = methodValueCallFrameObjs[:]
|
||||
} else {
|
||||
p := funcdata(f, _FUNCDATA_StackObjects)
|
||||
if p != nil {
|
||||
n := *(*uintptr)(p)
|
||||
p = add(p, goarch.PtrSize)
|
||||
r0 := (*stackObjectRecord)(noescape(p))
|
||||
objs = unsafe.Slice(r0, int(n))
|
||||
// Note: the noescape above is needed to keep
|
||||
// getStackMap from "leaking param content:
|
||||
// frame". That leak propagates up to getgcmask, then
|
||||
// GCMask, then verifyGCInfo, which converts the stack
|
||||
// gcinfo tests into heap gcinfo tests :(
|
||||
}
|
||||
}
|
||||
|
||||
return
|
||||
}
|
||||
|
||||
var methodValueCallFrameObjs [1]stackObjectRecord // initialized in stackobjectinit
|
||||
|
||||
func stkobjinit() {
|
||||
var abiRegArgsEface any = abi.RegArgs{}
|
||||
abiRegArgsType := efaceOf(&abiRegArgsEface)._type
|
||||
if abiRegArgsType.kind&kindGCProg != 0 {
|
||||
throw("abiRegArgsType needs GC Prog, update methodValueCallFrameObjs")
|
||||
}
|
||||
// Set methodValueCallFrameObjs[0].gcdataoff so that
|
||||
// stackObjectRecord.gcdata() will work correctly with it.
|
||||
ptr := uintptr(unsafe.Pointer(&methodValueCallFrameObjs[0]))
|
||||
var mod *moduledata
|
||||
for datap := &firstmoduledata; datap != nil; datap = datap.next {
|
||||
if datap.gofunc <= ptr && ptr < datap.end {
|
||||
mod = datap
|
||||
break
|
||||
}
|
||||
}
|
||||
if mod == nil {
|
||||
throw("methodValueCallFrameObjs is not in a module")
|
||||
}
|
||||
methodValueCallFrameObjs[0] = stackObjectRecord{
|
||||
off: -int32(alignUp(abiRegArgsType.size, 8)), // It's always the highest address local.
|
||||
size: int32(abiRegArgsType.size),
|
||||
_ptrdata: int32(abiRegArgsType.ptrdata),
|
||||
gcdataoff: uint32(uintptr(unsafe.Pointer(abiRegArgsType.gcdata)) - mod.rodata),
|
||||
}
|
||||
}
|
||||
@ -648,97 +648,6 @@ printloop:
|
||||
}
|
||||
}
|
||||
|
||||
// reflectMethodValue is a partial duplicate of reflect.makeFuncImpl
|
||||
// and reflect.methodValue.
|
||||
type reflectMethodValue struct {
|
||||
fn uintptr
|
||||
stack *bitvector // ptrmap for both args and results
|
||||
argLen uintptr // just args
|
||||
}
|
||||
|
||||
// argBytes returns the argument frame size for a call to frame.fn.
|
||||
func (frame *stkframe) argBytes() uintptr {
|
||||
if frame.fn.args != _ArgsSizeUnknown {
|
||||
return uintptr(frame.fn.args)
|
||||
}
|
||||
// This is an uncommon and complicated case. Fall back to fully
|
||||
// fetching the argument map to compute its size.
|
||||
argMap, _ := frame.argMapInternal()
|
||||
return uintptr(argMap.n) * goarch.PtrSize
|
||||
}
|
||||
|
||||
// argMapInternal is used internally by stkframe to fetch special
|
||||
// argument maps.
|
||||
//
|
||||
// argMap.n is always populated with the size of the argument map.
|
||||
//
|
||||
// argMap.bytedata is only populated for dynamic argument maps (used
|
||||
// by reflect). If the caller requires the argument map, it should use
|
||||
// this if non-nil, and otherwise fetch the argument map using the
|
||||
// current PC.
|
||||
//
|
||||
// hasReflectStackObj indicates that this frame also has a reflect
|
||||
// function stack object, which the caller must synthesize.
|
||||
func (frame *stkframe) argMapInternal() (argMap bitvector, hasReflectStackObj bool) {
|
||||
f := frame.fn
|
||||
argMap.n = f.args / goarch.PtrSize
|
||||
if f.args == _ArgsSizeUnknown {
|
||||
// Extract argument bitmaps for reflect stubs from the calls they made to reflect.
|
||||
switch funcname(f) {
|
||||
case "reflect.makeFuncStub", "reflect.methodValueCall":
|
||||
// These take a *reflect.methodValue as their
|
||||
// context register and immediately save it to 0(SP).
|
||||
// Get the methodValue from 0(SP).
|
||||
arg0 := frame.sp + sys.MinFrameSize
|
||||
|
||||
minSP := frame.fp
|
||||
if !usesLR {
|
||||
// The CALL itself pushes a word.
|
||||
// Undo that adjustment.
|
||||
minSP -= goarch.PtrSize
|
||||
}
|
||||
if arg0 >= minSP {
|
||||
// The function hasn't started yet.
|
||||
// This only happens if f was the
|
||||
// start function of a new goroutine
|
||||
// that hasn't run yet *and* f takes
|
||||
// no arguments and has no results
|
||||
// (otherwise it will get wrapped in a
|
||||
// closure). In this case, we can't
|
||||
// reach into its locals because it
|
||||
// doesn't have locals yet, but we
|
||||
// also know its argument map is
|
||||
// empty.
|
||||
if frame.pc != f.entry() {
|
||||
print("runtime: confused by ", funcname(f), ": no frame (sp=", hex(frame.sp), " fp=", hex(frame.fp), ") at entry+", hex(frame.pc-f.entry()), "\n")
|
||||
throw("reflect mismatch")
|
||||
}
|
||||
return bitvector{}, false // No locals, so also no stack objects
|
||||
}
|
||||
hasReflectStackObj = true
|
||||
mv := *(**reflectMethodValue)(unsafe.Pointer(arg0))
|
||||
// Figure out whether the return values are valid.
|
||||
// Reflect will update this value after it copies
|
||||
// in the return values.
|
||||
retValid := *(*bool)(unsafe.Pointer(arg0 + 4*goarch.PtrSize))
|
||||
if mv.fn != f.entry() {
|
||||
print("runtime: confused by ", funcname(f), "\n")
|
||||
throw("reflect mismatch")
|
||||
}
|
||||
argMap = *mv.stack
|
||||
if !retValid {
|
||||
// argMap.n includes the results, but
|
||||
// those aren't valid, so drop them.
|
||||
n := int32((uintptr(mv.argLen) &^ (goarch.PtrSize - 1)) / goarch.PtrSize)
|
||||
if n < argMap.n {
|
||||
argMap.n = n
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
return
|
||||
}
|
||||
|
||||
// tracebackCgoContext handles tracing back a cgo context value, from
|
||||
// the context argument to setCgoTraceback, for the gentraceback
|
||||
// function. It returns the new value of n.
|
||||
|
||||
Loading…
Reference in New Issue
Block a user